All gasses expand when heated up, meaning that their molecules spread out and thus fewer molecules occupy the same amount of space. Thus, hot air has less oxygen and cold air has more. Today we’re going to talk about how important air density is and how you can maximize your power production by paying close attention to charge temps. We’re also going to look at how air density varies when under boost and when at atmospheric pressures and how temperature can actually cancel out boost – if it’s not controlled!

The more tightly packed the air (the colder it is), the more oxygen we can cram into the cylinder to create power. This is similar to the idea of forced induction (turbo/supercharging), by compressing air we can also force more molecules into the engine with each stroke. However, in naturally aspirated engines, one of our only tricks to cram air into the cylinders is by breathing in the coldest air possible.

So the eternal battle over “short ram” versus “cold air” intake systems usually revolves around intake temperature. Short ram intakes for most vehicles place the conic air filter under the hood and thus are subjected to higher than ambient temperatures whereas cold air intakes take in roughly ambient temperature air.

Factory intake systems vary, but most of them are of the “cold air” variety in that they draw air from an area that is typically close to or at the temperature of the air around the car. Some heating of the intake charge does occur, especially at small throttle angles. However, especially at wide open throttle, the intake charge is moving so fast and the temperature differential between the air and the surfaces it’s in contact with so small, there’s VERY little temperature rise in the intake charge.

Now, understand that if you’re driving around town at part throttle and then snap the throttle open, the intake air it initially pulls in will be slightly warmer than atmospheric (usually about 10 degrees warmer in a stock or CAI type setup). Are their gains to be had by keeping underhood temps down? It’s good to do in general (if nothing else to protect components from hot exhaust headers), but don’t expect any miracles and except in the case where you’ve added a huge heat source (like say, a big turbo) I wouldn’t be too concerned with this.

Getting the coldest air we can get though, is definitely important and below I’m going to show you why.

Using the chart below then, we can see that at 30 degrees air has a density of 0.081 lb/ft^3 and at 60 degrees it has a density of 0.076 lb/ft^3. That’s roughly a 6% difference in the amount of actual air being ingested and thus we can see that even a small hike in intake temperatures can make a pretty big difference in power output experienced in the real world. When intake temperatures are higher (perhaps due to lower speeds/higher radiator loads/heat soak/whatever), the differences are much more dramatic.

The old rule of thumb is that for every 10 degree hike in intake temperature, there’s roughly a 1% loss in power production. This is a really rough rule that in practice can vary quite a bit, but it gives you an idea of the importance of intake temperature.

Below is a charge of air density at differing temperatures as well as at atmospheric pressure (NA) and for comparison, at a very low boost pressure. Notice how much more density you get with a good turbo or supercharger setup.

Before mod

I have received numerous requests for a DIY on my snorkel mod that I detailed in the intelligent modification series from the IS300 community.

It is based on my measurements of restriction in the stock intake system, it does two things: reduces restriction imposed by factory snorkel/airbox, increases the availability of pressurized (higher than atmospheric pressure) air at speed. In effect, it adds additional “ram air” on the highway.

No exposed conic filter, even in this hardcore Ferrari.

Using a sealed airbox is ideal in any car that will be going through gears frequently (street car, road racing car). The reason is that even if it doesn’t produce the highest hp, which sometimes it does, is that transient response is better with an airbox than with an open element air filter. When the throttle closes between shifts for example, the air that was quickly rushing in hits a wall and is forced back down the intake system. In a sealed system, the air actually bounces back and helps ram more air in when the throttle is re-opened. In a open air filter system, the air is lost to the atmosphere and thus power just after a shift is harmed. There are other reasons, but the best “proof” of this is that even the hardcore no-creature comfort exotic cars like the Ferrari Enzo DO NOT use open element air filters, but still – air boxes.

The factory air box generates more and more air pressure as the car speeds up, by replacing the airbox with a “open element” conic filter, you lose that benefit completely. Just pointing the snorkel at it just supplies it with the outside air, not the pressure.

That said, this modification reduced restriction more than the popular “JoeZ” intake and is probably akin to the infamous “Area 51″ intake but it costs about $20 to do, less if you already have the hose to do it. As a bonus, it’s almost impossible to detect, it adds very little if any noise AND you get to use power tools…

Please read these before doing this (or any air intake) modification on your IS300:

• Intelligent Modification: Measuring Intake Restriction (Part I)
• Intelligent Modification: Measuring The Intake Restriction on Project Lexus (Part II)
• Intelligent Modification: Doing Some Intake Mods on Project Lexus (Part III)
• More Bad News for “Drop-In Air Filters”
• Yet another nail in the coffin for “drop-in” filters…
• MAF vs Differential Pressure for Intake Testing

Hint: One hint that the IS300′s snorkel is a tad undersized is the size of the GS300′s snorkel. The original 2JZ-GE kidney snorkel was much bigger, but due to packaging reasons the IS300′s is a smaller version. The GS300′s 2JZ-GE also makes slightly more power (probably due to slightly different intake, header, and exhaust).

What you need for your TU Snorkel Mod

• - 2-2.25″ flexible plastic tubing (I used a shop vac hose from Home Depot, $19.99 for way more than I needed). If you can find something flexible with no ridges (smooth inside) that would be BETTER.
• Zip tie (to mount hose to grille)
• Correct size hole saw (2-2.25″)
• 10mm socket, extension, ratchet, pliers to remove hose clamps on vacuum hoses.
• Cost is between Free and $20-25, maybe a little more if you need to buy a hole saw.

As a note, the only reason I didn’t use a bigger pipe for the snorkel is there’s no room. There’s no room to install a snorkel anywhere else (under, beside, etc) due to the way the engine bay is built. If you used a terrible filtering, horribly flowing HKS you could fit a better snorkel, but the tradeoffs would be too high. Use a factory air filter for BEST results, period.

Step 1: Get the airbox out

To remove the airbox, just remove the visible 10mm bolts that hold the air box down. If

Remove air box by removing 10mm bolts and losening hose clamp with screw driver.

you have a JoeZ intake or similar, make sure you remove your strut tower bar before doing any of this or you’ll scratch it like I did mine. The JoeZ -does- reduce restriction, so I kept mine but this snorkel mod does more in my testing.

Use a screw driver to loosen the clamps on the intake, carefully lift the air box and disconnect the solenoid and vacuum hoses on the driver side of the airbox (on the bottom).

Step 2: Fit the hose

Fits tightly (slightly crimped) between headlight and radiator support

I believe the shopvac hose I used was 2″ throughout and 2.25″ or 2.5″ even at the box. I chose to put the big end going into the box. Route it through the hole as shown beside the passenger side headlight. It will be “crimped” a bit. While that’s not ideal, my testing still shows that the net result is a good one. I ran mine down and zip tied it to the lower grille area. I used a black zip tie so it’d blend in. To attach, poke 2 or 3 SMALL holes in the plastic pipe and use those holes to attach the zip tie.

It'll fit, I promise.

Bonus: If you happen to have a velocity stack laying around or something like that, you might want to attach one here. You can make your own “flared” entry by forcing a piece of straight plastic pipe or something over a bowl or flower pot. I tested mine with a blunt entry and do not know if the velocity stack would help or make no difference.

Use hole saw to cut hole in box

Step 3: Cut the hole out

Figure out which size hole saw will allow a nice tight fit into the hole and cut the airbox as shown. The EXACT location isn’t that important, but you want it to be straight on. I basically test fit the airbox after putting my piece of shop-vac hose through the area beside the headlight and marked where it would hit.

Step 4: Reinstall

That’s pretty much all there is to it. Cut the hose down to size of course. If you have a gap around the sides of the hose, I suggest using a cut up beer koozie (neoprene sleeve) to wrap around and create a tight seal. I don’t recommend using silicone or anything like that as anytime you want to remove the airbox you’d have to redo the silicone. A fairly tight fit is good enough, it doesn’t have to be water tight or anything like that.

Step 5: PROFIT!

For $20 you just did more for your IS300 than other intake systems available for the car. The additional “ram air” will also help some with your highway mileage by reducing pumping losses. Pumping losses are basically losses caused by running your engine with the throttle only slightly open. The engine has to work very hard to pull air around the throttle and thus efficiency is lost. No worries about hydrolock, even if the secondary snorkel becomes completely submerged, the primary snorkel will provide more than enough air flow to keep the secondary from sucking up water.

You may (just like the factory system) note some water drops get in the box after a car wash or heavy rain, but that’s no big deal and it happens in the OEM configuration as well.

If you find a good source of a piece of tubing that is smooth and fits, please post a comment of where to get it. Also, if you do any actual testing and get a “better” design, please also comment on that so everyone can see that. I myself will probably not do much more with this project but I’m happy to pass along information.

Don't waste your time with "drop-in" filters

I’ve been saying it for years, but “drop-in” air filters such as those marketed by multiple major names are unfortunately, mostly a sham.

I have yet to see a single vehicle where when I measured pressure drop across the filter that a drop-in filter made a measurable improvement. Pressure drop by the way is NOT a measurement of flow, but rather an indirect measurement of flow (by measuring how much air pressure has been lost from one point in a pipe system to another), one which especially in the case of filters is more accurate than a flow bench.

We’ve already talked about the poor filtering of these “aftermarket high flow filters” here, but let’s explore flow again.

Anyhow, I came across a great article written by Mance Etheredge. I tried to find a way to contact him to give him props for his work but I’ll have to settle for a shout out here.

Mance measured the air flow (on a flow bench rather than my more DIY method) of several drop-in air filters for a 12v Audi. I recommend you read his article to see the full low-down on the “high flow” filter vs the factory vs the factory replacements.

http://12v.org/audi/afcompare/

Note that the tested K&N flowed nearly the same as the factory Audi filter, but all the other “cheapo” filters flowed worse to significantly worse. The Purolator “oem replacement” filter in the test actually flowed 110cfm LESS than the factory filter, all the rest of them were worse than factory. I -have- seen instances where cheapo air filters created more pressure drop than factory (and ironically, many “aftermarket performance” filters too).

Bear in mind these numbers are pure “flow”… nothing more, nothing less. They don’t address or speak to any pressure differentials once mounted in the airbox.

So yep, even though the K&N’s *slight* itty bitty flow (“4″ cfm – almost within the margin of error) increase seems to suggest there might be something there, as seen in my own hands-on testing – there isn’t. I can assure you that other brands are the same, and often worse. K&N is actually the better one of the group since the closest aftermarket “oem replacement” filter is a full 50cfm lower than the actual OEM filter.

Nothing wrong with K&N as a company, and while yes they are fine reusable filters, you won’t find an easy “drop-in” horsepower gain with them. OEM filters are usually very inexpensive and they’re of known quality.

Is the horse dead yet?

Better to focus on ways to reduce pressure drop in other places in the system than with a filter replacement regardless of the brand or product claims. For example, by fitting a different snorkel or smoothing out the intake arm for example.

See my article on “Intelligent Modification” for more information on pressure drop and how to go about those kinds of more meaningful modifications.

Maxlux (right), Phillips OSRAM/Lexus OEM (left)

OEM and even aftermarket HID replacement bulbs are expensive, but I found a set of bulbs so cheap it’s almost unbelievable.

The other night the passenger side bulb on project Lexus turned a nice shade of purple. The next time I turned on the lights, the passenger bulb was dead.

I priced the OEM bulbs at about $90 each bulb! ouch! $180 to replace bulbs? There are full HID conversion kits for less. Aftermarket bulbs varied around $40-80, each bulb, still in the $80-160 range for a pair.

I wanted to keep the standard 4300k temperature rating as I don’t care for the “blue” or “purple” lights and my understanding is that the closer to sunlight (around 4300-4500k) you are the better your actual visibility. 6000k and beyond actually have less visibility than the typical OEM color which is around 4300k. The number has nothing to do with how bright it is, everything to do with the color.

Anyway, I found a “generic” bulb on Amazon from Maxlux that I thought I’d give a shot. It was $36.99 for a PAIR which is so stinkin’ cheap that even if they sucked, it was worth a try at least. Maxlux seems to offer other HID bulb sizes too (D4R, D2S,=, etc) as well as some kits which I can’t say anything about as I’ve never used them. None the less, worth looking into if you’re looking for HID bulbs.

The bulbs are slightly shorter than the factory bulbs and the base is slightly different but fitment was perfect. I replaced the passenger side bulb first and drove around with one factory and one Maxlux bulb for about a week. There was no significant color difference and if anything the new bulb was brighter (probably more due to being new than anything) and closer to white than the factory one (also probably due to age).

Today I replaced the driver’s side bulb because I like to have a matched pair and the driver bulb is likely to burn out soon anyway.

TIP: I saved the driver’s side bulb as I like to keep a spare bulb for “mission critical” lights in the trunk in case I need it and I’m unable to get to a store for some reason (which has happened before).

I’ll update this page in a while if I come across any premature burnout issues, but everything so far seems great. For nearly $140 less than factory replacements, if you’re replacing your factory HID bulbs (D2R or D2C), you should take a look at these. Even if they last half as long, they’re still significantly cheaper and I highly doubt they will. There are almost 4 sets of these before you buy a set of OEM bulbs, food for thought.

Note For IS300 Owners Only: There is no need to remove the bumper to change low beam bulbs. Just twist off the cover and work carefully. It’s tight, but even with large hands you should be able to do it in 5-10 minutes per side, easily. Wear nitrile or latex gloves.

A subscriber, John Marlow, recently submitted a question that I thought I’d take a few moments this week to talk about. I also saw a similar question out on one of the forums that had linked to an article here so I figured it was worth talking about.

“Why not just measure intake restriction using an OBDII tool to read MAF (Mass Air Flow Sensor) values (on cars equipped with a MAF) and determine if flow is better that way?” — John Marlow, Topeka, KS

Digital Differential Pressure Meter

Thanks John for your question!

This is actually really good thinking and using the MAF to see if a modification helped or not would be better than the “butt dyno”, but I still lean on the differential pressure meter for some reasons I’ll discuss in this article.

As long time readers know, I like to use a differential pressure meter (or vacuum gauge, or digital manometer) to measure restriction in the intake system to guide modifications to that system. I like to use this rather than the MAF sensor because with a differential pressure meter, I can take measurements at different points in the system while the MAF only allows an overall figure. If I want to know if a particular bend is restrictive or if the resonator box is causing the problem, I can use the DPM (differential pressure meter) to measure the pressure drop across those parts individually and figure out which is the culprit of my flow loss.

The MAF measures a few different things while differential pressure only measures pressure drop which makes MAF readings less repeatable which is important for “scientific” modification. MAF readings are also much harder to measure on a OBDI (pre-1996) car.

So let’s unpack some of these points a little bit to make more sense of them.

The MAF (Mass Air Flow Sensor) literally measures how much air is flowing through the intake system and into the engine. It measures the MASS of the air, not the volume. The volume of air going into the engine is almost always the same, its mass (or how much actual air is in that space) changes with air temperature, pressure and humidity.

On the surface that seems like a great way to compare two different intake setups.

However, the mass air flow sensor measures the total amount of air by sensing the amount of air, velocity, temperature and even humidity all at one time. In other words, the MAF is a very good indicator of exactly how much air flow is going through the pipe. However, in different locations at different times, the exact same intake system would produce different values. Changing other engine components downstream (in the engine, header, etc) could also alter MAF readings somewhat.

Two sets of back to back readings from a MAF generally follow a similar line and you could try to average the data plots and use a best-fit line and all of that to compare two MAF graphs, but it’s an enormous pain and it may still give deceptive results, especially with the relatively small changes in air flow that intake mods yield.

Just because one intake gives you better MAF values on a few runs doesn’t necessarily mean it’s better – unless they MAF values are drastically different and the tests were done as closely together as possible.

“Geeky” Project Idea

You could possibly use a MAF under lab conditions as a very inexpensive “flow bench.” I may build one at a later date if I have the parts laying around. If you can control temperature, conditions and atmospheric pressure of the air flowing through the MAF, it’d be an awesome way to measure flow for really cheap given a 12v power supply and the right fixtures. I know a few small but VERY successful Formula teams that use a “flow bench” using a differential pressure meter on their cylinder heads and so on. They use a heavy duty shop vac, a custom built plenum then mount the cylinder head to a seal on the top of the plenum. They use the differential pressure meter to see how much pressure drop they have at different valve lifts. Very slick.

The MAF only allows us to see the birds eye view of air flow. In other words, we can’t use the MAF to figure out where in the factory intake system the restriction is hanging out. The power of using a differential pressure meter correctly is that you can actually locate exactly what’s causing the restriction. Using the MAF method, you could only make random modifications and see if they worked. Using the DPM method you can make targeted changes which saves time (and probably money).

The Ferrari Enzo has no "creature comforts", but still uses enclosed air boxes..NOT exposed conic air filters.

In my experience, modified factory systems generally produce better results than aftermarket systems that completely scrap the box. They are certainly cheaper, quieter, cleaner (both visually and in terms of engine wear), and in almost all cases they out perform the aftermarket system when done correctly – in the real world, not always on the dyno. If you listened to the TU Premium Interview with John Grudynski, the fastest car isn’t necessarily the most powerful, it’s the one with the power AND good transient response which the second is where boxed systems shine and why I suspect you’ll never see even the most hardcore Ferrari  or Lamborghini with an exposed air filter like most aftermarket systems.

I use the differential pressure method because it allows me to get repeatable results on which places in the system are “clogging up the pipes.”

Differential pressure, rather than MAF readings, measure what’s known as pressure drop. Pressure drop has nothing to do with the actual amount of air flow, per se. It’s related but that’s not what it’s measuring. Instead, for our purposes anyway, it’s simply a measurement of restriction. Pressure drop is caused anytime there is a restriction to flow whether that be a sharp bend, an obstruction, excessively rough surface, excessive length or a really crazy phenomenon known as turbulent flow.

Laminar flow is straight and clean flow.

There are two types of air flow, Laminar flow and Turbulent flow. Laminar flow is very predictable flow and most air flows this way. Turbulent flow is an area of deep research and there is actually a very significant prize available in the academic world (I believe $1M) for anyone who can even give a somewhat decent theory of turbulent flow that can be used to model flow in these situations. Turbulent flow is how air behaves when it’s moving really, really fast.

When air becomes turbulent there is typically a lot of pressure drop that can be seen according to my favorite physicist.  Therefore, differential pressure readings can account for or even expose turbulent flow should it become and issue.

Turbulent flow is much more chaotic and hard to model

Pressure drop is an indication that air flow is going down but it’s not a direct measurement of air flow.It’s also a very sensitive measurement if you’re using a small unit like inches or centimeters of water.

Obviously, measuring MAF voltages on an OBDI car can be done, but you need expensive equipment to do that accurately and so on older cars, the MAF reading thing is completely out.

Finally, while measuring a MAF reading on an OBDII car is easy with an OBDII reader with datalogging capabilities, the results require much more analysis and care to be useful.

In short, I still recommend the differential pressure meter as a tool in your tool box. It is universally applicable so you can use this “modding tool” on any vehicle and in addition to measuring intake restriction it can be used for measuring aerodynamic pressures and determining the best place to put intake ducts and cooling vents for brakes, passengers, etc.

Here are a few descriptions from websites/manufacturers selling these, notice the trend of extremely vague language:

The SPOON Low Temp Thermostat S2000 Integra Civic will increase the vehicles cooling ability (false) by changing the operation temperature from 90C (stock)[194] to as low as 80C [176F]. This in turn will give your Honda a chance to be free of overheating (false). For best results, it is recommended that the Thermostat be used in conjunction with a low temperature Thermo Switch.

The SARD Low Temperature Thermostat – SST12 Mazda is a drop-in direct replacement for your OEM unit. The Sard unit will lower the temperature at which the cool water can mix with the warmer temperatures inside the engine (true). This will lead to a motor than can now run much more efficiently (false).

The FEEL’S Low Temperature Thermostat Civic FD2 will provide better, more reliable and faster cooling for your FD2 (false). By lowering the opening temperature to 68 degrees, and full open at 82 degrees there is a smooth transition in cooling (???), and you engine will be cooled optimally faster (?).

The MUGEN Low Temp Thermostat NSX S2000 will increase the vehicle cooling ability (still false) by allowing the circulation of the chilled water earlier than the OEM unit would allow it to (that part, true). Stock thermostats are intended for normal driving conditions and aren’t made for those intending to give their car a work-out (false).

Reading these make you believe that a low temp thermostat are a good idea for those “pushing their car harder” and that they somehow improve cooling performance. There are other descriptions that also seem to indicate that they lower engine/intake temps to make more power. All rubbish.

The Function of the Thermostat & Cooling System Basics

The biggest misunderstanding about thermostats is that people believe they make the engine run cooler. They don’t necessarily do that. The cooling system and load on the engine determines how hot the engine gets, the thermostat fully open will still be the mercy of the coolant system’s ability to remove heat.

Most engines run slightly above the thermostat’s minimum opening temperature under normal loads. Under high loads, they will run at or above the thermostat’s fully open temperature – in other words, under hard driving, the thermostat’s opening temperature is completely irrelevant.

The thermostat can only determine when the cooling system is allowed to start cooling the engine. It sets a floor, not a ceiling on engine temperatures. The thermostat basically behaves like the hot and cold knobs in your shower, if the water is too hot, it turns the cold on a little more and if the water is to cold, it turns up the hot water.By regulating the flow through the cooling system it speeds up and slows down the flow of coolant into and out of the engine block.

In liquid cooling systems, the ability to cool is determined by a number of factors, but the basic keys are the surface area of the radiator (how big/how many small fins), the air flow through the radiator (fans on/off, speed of car), and how quickly or slowly the cooling fluid goes through the radiator. If the coolant spends a small amount of time in the radiator, it loses less heat. If it spends a lot of time there, it loses far more heat. Therefore you don’t want the flow to be too high as the cooling system’s ability to cool the engine will be reduced, not increased.

The thermostat is there primarily to help the engine warm up in the morning. As we discussed in a previous article, the engine is designed to operate at it’s operating temperature. Most engine wear occurs when the engine is cold, once it’s warmed up there is very little wear in a healthy engine. Thus, we definitely want to run a thermostat to allow the engine to warm up as quickly as possible until it reaches our desired and designed operating temperature.

If the engine is below operating temperature, the bearings, rings, and other components are expanded in size and therefore they rub against the other metals in the engine more than they would at operating temperature. No good.

So if we don’t run a thermostat at all, it takes a lot of constant load to get the engine properly warmed up and to keep it up to temperature on cold days. We also in some circumstances may experience overheating if flow through the system is too high as the coolant has to spend a certain amount of time in the radiator to actually cool down.

Some race teams do choose not to run a thermostat, but they are the minority. They usually run at least a restriction plate in place of the thermostat to slow down flow and allow some warm up to occur.  The reason that they may not run one at all is usually to remove a point of failure in endurance type races. In other words, if the thermostat fails and sticks closed, it could cause a pit stop or end the race. By removing it, they tolerate possible engine wear since they know they’ll be at high loads throughout the race. Their cooling system is usually tuned to compensate for the lack of a thermostat as well.

Running the factory thermostat will on the other hand ensure that the engine comes up to the designed minimum temperature very quickly. Until the engine is up to temperature, there is no cooling occurring. The factory thermostat will not however change how the engine runs under load because the thermostat will be fully open when under load. It effectively isn’t there under load.

What they’re used for

So what then would a low temperature thermostat accomplish? Not much.

Around town and in the pits, you warm up faster than no thermostat at all, but you will take a while to warm up from 160 to 180 for example. You will get there however, especially on warm days, the only difference is you’re trying to cool the car off as it’s trying to warm up. As a mater of fact, if you sit there at idle, the temp will go up until the radiator fans kick on since radiators are poor cooling devices without air flow. In other words, sitting still, the thermostat opening temperature doesn’t matter much at all.

Once you’re moving, on the highway, with a 160 degree thermostat on a cooler day you could be cruising at 160-180 degrees (opening temp->designed operating temp). This is possible because the load on the engine is low and the outside temps are low. Therefore, the thermostat opening temp maters somewhat here. If you’re coasting down a mountain, it will be a certainty that your coolant will reach the thermostat minimum if you coast long enough.

The problem with a low temp thermostat then for regular driving is that there are times when the car will be running at a temperature lower than it’s design intended. The result is increased wear on the engine’s internals. It’s essentially the same as if you assembled the engine with clearances tighter than designed for because you didn’t follow the directions or your tools were not calibrated properly.

As for the intake temperature argument, while cooling the intake manifold down could be useful, there are a few problems with the argument. The first is that very little heat is transferred from the intake manifold to the intake charge, period. The intake charge is moving very fast and there is a LOT of air flowing through. The surface area of the intake system is very small and the temperature differential in real terms is not that high. There is already very little heat being added to the intake charge by the intake system regardless of what some ads claim. If the new thermostat DID bring the temps of the intake manifold down 20 degrees, the actual change in intake temps would be negligible to 0 on the road.

Regardless, it would take literally a second or two before temps would be regulated by the cooling system, not the thermostat anyway since under load the engine is going to run well above the thermostat fully open mark anyway.

Remember that the thermostat is fully open pretty much any time the engine is under full load because the coolant temperatures spike pretty quickly.

In a race car, the floor (opening temp) of the thermostat is completely irrelevant unless you are running a very efficient and large radiator. Once you’re out on the track for half a lap or so, your coolant temps are going to be in the 200 range anyway so the thermostat is fully open regardless.

You can use a low temp as a “band-aid” at the track sometimes. For example, if you know that your coolant temps are hitting the opening temp of your current thermostat at points the track and you’re experiencing mild overheating, you might be able to patch this up by using a lower temp thermostat, especially if you’re willing to run your radiator fans manually to help.

Why? Because during low load parts of the track you allow the coolant system to cool off more which means it will cope with higher load sections a bit better and may chase of mild overheating problems. This is acceptable on a race track as a temporary solution as wear is usually an acceptable compromise to get through the race. However, the right solution is to upgrade the radiator or check for possible malfunctioning sections of the cooling system. It is also more acceptable here because load is high during a race. On the street, even on hard drives, it’s usually reasonably low.

Conclusion

So if you want to test this, the best thing to do is get an OBDII scanner and go out in an OBDII car and monitor the ECT sensor and watch how coolant temps regulate and spike as load changes.

The bottom line however is that in a street car, you’re increasing wear and getting no benefit. In a race car, it’s a band-aid but not one that you should plan to rely on.

If you’re having overheating problems, check the cooling system thoroughly and if all is well, upgrade the radiator, fans or even the water pump — not the thermostat. If your coolant gauge never goes above normal then your cooling system is adequate for your use of the car.

If you’re chasing more power, this isn’t a place to look. Any power gain would be circumstantial (ie, only under certain conditions), incredibly negligible, and at the risk of accelerated wear on your expensive engine internals (especially in street cars).

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MP3 Recording and PDF Transcript of Interview available to TU Premium Members

John has been designing and building race headers for many major racing series and organizations such as SCCA, USAC, Trans-Am, World SportsCars, Dirt Track and NHRA Drag racing for nearly 30 years. He is easily one of the foremost experts on the “black art” of Header design and has an incredible reputation in motorsport and in the aftermarket.

John has also developed some seriously impressive aftermarket headers for cars such as the Honda Integra Type-R (which gained almost 20hp over factory), the Eclipse V6, the RSX Type-S and many more.

John also earns the distinction of being recognized as one of the Tuner University Certified Experts and the first to receive the honor. This honor is one given only to companies and individuals who have earned their stripes and demonstrated unique abilities and innovations in motorsport, OEM, and aftermarket parts/services.

During the interview, John shared his story about how he came to be in the “header” business and along the way he demonstrated his intense passion for creating only the best exhaust systems.

As we spoke, John talked about the importance of understanding that the fastest car is the one that gets around the track (or down the strip) the fastest. He pointed out that while the dyno and other tools give us valuable information that ultimately it’s the track that tells us what the fastest combination of parts is. In one example, he explained how one of his race teams went to the track and tested several setups and when the dyno results were in, the fastest setup was actually the one that put down “average” even unexciting dyno numbers compared to the other setups in the test.

The interview went on for a little over an hour, but here are just a few of the other incredible nuggets of wisdom John revealed:

• Non-sequential vs sequential pairing of cylinders in header design and how you can use this technology from Formula Atlantic cars to uncover hidden power
• When to use a “4-1, 6-1, 8-1  collector” vs a “Tri-Y” 4-2-1, 6-2-1, etc, style collector
• Why a bigger exhaust may produce more power on the dyno, but not always a faster car
• An incredible and EASY trick that almost anyone can use (especially on newer cars) to improve the flow of their factory catalytic converter and often achieve the same gains as an aftermarket header while remaining completely legal and “eco-friendly”
• Why the key to a faster car is transient response, not necessarily horsepower.
• How John’s favorite “anti-reversion” chamber technology works and how these unique chambers add power and improve transient response.
• 2 very valuable recommendations for aftermarket “high flow” catalytic converts that don’t fail every 10,000-15,000 miles. Hint: one of them is used to legalize exotic cars imported to the United States and has been used on cars such as the McLaren F1.
• Lessons from the incredibly competitive Formula Ford racing series that you can apply to your car, regardless of the manufacturer
• The simple but very counter-intuitive tweak to the collector of your header that can create HUGE power gains for you. Almost no aftermarket header utilizes this trick but it’s been an exploited trick in F1 for decades.
• How to best size your exhaust system for the street
• Exactly how John was able to extract 20 horsepower from the already highly developed Integra Type-R engine almost on his first try. Where he started and what created the majority of the gains.
• Why you shouldn’t run an open header, but how you can still get maximum power
• and a LOT more.

The full 1 hour and 12 minute audio recording of this interview (in John’s own words, recorded live) as well as the FULL 25 Page written transcript of the interview are some of the many benefits available to Tuner University PREMIUM members

If you’re already a PREMIUM member, please login here to download the interview.

Maybe you’ve wondered how removing 100lbs will affect your car in terms of how much horsepower you’d have to gain to accomplish the same thing.

These questions are wise to ask because they can be used to make significantly better modification choices and frankly it can be fun to “simulate” different modification scenarios.

For example, if I could buy a carbon fiber hood that weighs 20lbs less than factory, it’d be nice to be able to view that weight loss in terms of horsepower. In other words, how many horsepower would I need to gain in order to accomplish the same thing as losing 20lbs? (Hint: it’s pathetically little)

What if I wanted to determine if a dual exhaust system is worth while? How much more power would I have to make to offset the extra 20lbs? (in a 3500lb car with 215 hp, not even 1.25hp, so probably do-able)

Can someone on the forum claiming to feel a 1-2hp gain on their butt dyno really do so? Well, using this formula you’d see that they’d have to be able to feel the difference between having groceries in the car vs not having groceries in the car to “feel” that supposed gain.

What about if I wanted to see how much weight I’d have to lose to compete with the same car with 50 extra horsepower?

All of these kinds of questions can be answered with the simple math in today’s article.

Weight to Power

You’ve probably heard power-to-weight more than weight to power, they’re the same thing but one has nicer numbers and a better visual representation so I’ll be using weight to power for this discussion.

Weight to power is one way to get a general idea of acceleration performance. For example, if I have a 3500 lb car with 215 horsepower, I simply divide 3500 by 215 to get a weight to power ratio of 16.28 lbs per horsepower. The same car with 250 hp would have a weight to power ratio of 14 lbs per horsepower.

To give you a really over simplified visual, imagine that each “horsepower” is a horse. The fewer pounds the horse has to drag with it, the easier it is for it to run.

The Bugatti Veyron with 987 bhp and a curb weight of 4,162 lb has only 4.12 lbs/hp and thus is significantly faster than our example car.

Great, that’s all very simple. So how is this useful beyond comparing vehicles to one another?

Well, let’s go back to the 3500 lb car with 215 horsepower example. Let’s say I want to know how losing 100lbs would translate into horsepower gained, because let’s face it, most of us think in terms of horsepower gains.

So we take 3500 lbs (the original weight) and divide by 215 to get 16.28 again (rounding for simplicity, you’ll want to use the full number to get accurate results).

We take 3400 lbs (the new weight) and divide by 215 to get 15.81 lbs/hp. That is better of course, but what would that mean in terms of horsepower? Well, we do some simple Algebra to see what horsepower we’d have to have with the original weight to get the same weight-to-power. Stick with me as this is really cool/useful:

3500 / x = 15.81 (Non-geek translation: original weight divided by some unknown horsepower would give us the same power-to-weight ratio as 3400 / 215). Solve for X (which I have done for you below)

“Weight loss” to “Horsepower” Formula

Old weight (3500) / New Power-to-Weight Ratio (15.81) = 221.38 hp

So that means that by taking 100lbs out of the 3500lb car, we would have had to gain ~ 6.38 hp (221.38-215, (the new-original horsepower) to accomplish the same thing WITHOUT taking out the 100lbs. Thus in this situation, 100lbs is roughly the same as if we had done something to gain 6.38hp. So to some extent, this means that something like an intake that adds +6hp would FEEL kind of like losing 100lbs (or a very skinny passenger) in this particular vehicle. In another car with different weight and power numbers, this figure would be different but calculated in the same way.

“Weight Gain” to “Power Loss” Formula

You can also use this same method to determine how adding weight is hurting you in terms of theoretical power loss. So if I add 50lbs of stereo equipment to the same car, it’s

Old Weight (3500) / New Weight-to-Power Ratio (16.74) = 209.08 hp

So that 50lbs of equipment is LIKE losing a little under 6 hp as those horses will now be dedicated to hauling that 50lbs.

This will give you a new way to think about weight and power. You can also go the other way and see how power gained changes the car in theoretical terms of weight, though I find this less useful. To do that, you say a 3500 lb car with 215 horsepower has a 16.28 lb/hp power-to-weight, and let’s say we gained 50hp to get up to 265 hp. That’s a power-to-weight of 13.2 lbs/hp. Now it’s simple Algebra again to figure out how much weight I’d have to lose off the car to make up the same amount of power:

In formula form:

New Power to Weight (13.2) * 215 (old horsepower) = Theoretical Weight (2838).

So 50 horsepower in this particular vehicle would be roughly the same as shaving off 662 lbs. As you can see from this math, this is why losing weight is rarely as useful as gaining horsepower, or at least, horsepower gain is significantly more practical and cost effective than weight loss in a production car.

Of course, this is also if we only take into consideration the acceleration effects of weight and power. In road racing or in a daily driver, weight loss is more useful than in drag racing. Of course, regardless of our goals, the least amount of weight necessary is best.

Hope this helps!

The HKS air filter (foam) flowed -slightly- better, but by slightly better, I mean less than 0.1 inches of water better which is so little that it literally makes no difference at all. The K&N was a similar story to the aFe.

I don’t care what your butt dyno says because frankly, it’s the most deceptive thing on the planet and you can’t feel a 1-2hp difference… no matter how good you are.

But there’s worse news for the drop-in filter crowd. Unfortunately, as expected, they also filter a lot worse than the factory paper air filter. Over time, that means more wear on your engine. Enough to matter? Maybe not, though some foam filters are pretty awful and I can only imagine how bad those cheap eBay conic filters are.

The bottom line is, don’t bother wasting money on a drop-in… the “every little bit counts” mentality will only result in wasted money and decreased reliability here. While there may be anecdotal evidence that these filters add power on a dyno, that’s all it is…anecdotal evidence. 1-5 horsepower is well within the margin of error on a dyno. In other words, it’s easy to have two runs back to back with a 1-5 horsepower difference…

Invest your money instead in a differential pressure meter and do the testing described in the “Intelligent Modifications” article, your money will go a lot further that way. I use factory air filters in my cars and I recommend you do the same.

Check the link for more information about the filter filtration test:

http://www.bobistheoilguy.com/air-filter-filtration-test/

Credit to Brian Turner, staff contributor for the Mesothelioma Cancer Alliance.

People love working with tuner cars because they get to bring something extraordinary and beautiful out of an ordinary car. However, beautiful and impressive as tuner cars are, they don’t come without drawbacks. When working with tuner cars, care need to be taken due to the harmful chemicals that you could potentially come into contact with, such as asbestos. Asbestos has been popular for use in auto industries and even though it has been regulated, many cars nowadays still have asbestos. Exposure to asbestos can cause mesothelioma, an aggressive and deadly form of lung cancer with a high fatality rate.

The parts of cars that have regular contact with asbestos are brake pads, hood liners, gaskets, valve rings, valve stem packing, and clutch assemblies. If you are working with a tuner car and are replacing any one of the above, care should be taken so you don’t accidentally come into contact with asbestos. Cars that were manufactured before 2003 most likely have car parts that use asbestos or parts that have come into contact with asbestos.

Another harmful chemical that is commonly found in tuner cars is lead. It’s used as an additive in plastics for automobiles and contact with lead can cause brain damage as well as damage to the kidneys and nervous system. Studies have shown that lead has an impact on the human’s reproductive health so if you are planning on bearing children, be sure to take good care in avoiding contact with plastics containing lead, if possible. The plastics in a car usually have bromine, a dangerous chemical that has been linked to many health problems.

Bromine is used in plastics to make them more fire resistant and improve the fire safety of the automobile. Another harmful chemical plastics in cars contain are Chlorine; used to make polyvinyl chloride. The polyvinyl chloride releases phthalates, a dangerous chemical compound that has been directly linked to infertility, premature babies, thyroids, kidneys, among other serious medical conditions.

By working with tuner cars, you might be coming into direct contact with these dangerous chemical compounds and care should be taken to minimize your contact at all, if possible. Awareness and prevention is the best way in ensuring your medical health when you work with car parts that could potentially harbor dangerous chemical compounds.

Want to contribute an article to Tuner University? Contact Me and tell me what you’d like to share. I do not take advertorials or promotional materials. However, if you have something valuable you’d like to share with my audience, let me know and we’ll see if it’s a good fit for TU.