High IAT's vs. PERFORMANCE

[SC2150]

Matt,have you followed our RX Spuer Chiller thread and the results on a Mammoth KB application?
http://www.camaro5.com/forums/showth...=99515&page=13

[old motorhead]

How much boost used and hp made on these runs. Unless I'm reading the graphs wrong, IAT's at the start of the run were 45 over ambient and ended up over 65 above ambient. Is that right or am I reading it wrong?

[M6HuggerSS]

Originally Posted by Matt@KB

AIR TEMPERATURE TESTING

Over the last 6 months there have been considerable discussions regarding air and water temperatures of supercharger kits. Comparisons are okay if they are accurate. If not they are just more misinformation circulating on the web.
And, it is not our intent to compare the design and efficiency of any kit or the individual mechanical components that influence air discharge temp. These are the supercharger, inlet tract, intercooler, heat exchanger, pump etc. Optimizing these parts lower the air discharge temps. resulting in greater HP and reduced detonation potential. “Hot air” under-hood inlets increase temps and hurt HP while adding an external real cool air kit does the opposite. One would have to be living in a village to not be aware of these basics.
Instead, we hope to point out the testing procedure and criteria we use at Kenne Bell to accurately compare the charge and coolant temps when dyno testing. Disregard any of the following 12 parameters and accuracy is compromised resulting in bogus comparison data. As you will see, it’s easy to skew the data with even the same car, kit, day, ambient and boost.
If any meaningful or accurate data is to be derived from comparing the air discharge temps of supercharger kits on a vehicle, it must be a controlled test with specific test parameters that ELIMINATE THE VARIABLES.
All the below will, and do, affect temperature when tested on a chassis dyno. One “kit” may wrongly appear superior or inferior on the same vehicle because of the simple temp or boost reading error or failure to note a cool air kit upgrade or open vs closed hood change to one kit and not the other.

VARIABLES THAT AFFECT COMPARISON TESTING
1) UNDER-HOOD TEMP (HOOD UP VS DOWN)
2) AMBIENT TEMP.
3) ACTUAL BOOST (1 PSI OF BOOST= 10*-15* SC air discharge temps.)
4) RPM, LENGTH OF RUN + GEAR RATIO
5) STARTING AIR TEMP
6) STARTING INTERCOOLER FLUID TEMP.
7) WATER VS. COOLANT RATIO
8) SUPERCHARGER TEMP.
9) INLET RESTRICTION
10) IDLE-RUN-AFTER RUN
11) WHERE THE ACTUAL CHARGE TEMP MEASUREMENT IS TAKEN
12) IMPROPER CIRCULATION (AIR TO WATER)

1a) FILTER TEMP- The ONLY measurement to use for “engine in” air temp. calculations. Other temp readings under, above or around the dyno or car are wrong. The engine draws air from the filter. Nowhere else matters. Keep in mind this temp. alters HP at 1% per 10* of variation. Also, cooler ambient air makes more boost.
1b) UNDER-HOOD TEMPS (HOOD UP VS DOWN)- Why do dyno operators insist on testing with the hood “up?” That isn’t the way the cars are driven. CLOSE THE HOOD- unless you want false air data. Under-hood temps. reach 200* vs 70* or ambient outside air. If the filter (inlet source) is located under the hood, then the dyno run should be conducted the same way- hood closed. Why is that so difficult to grasp for so many? What are they afraid of? Yes, the hot under-hood air will reduce HP, increase the detonation threshold, lower boost, alter supercharger efficiency and elevate engine and exhaust temps. Not good, but it is what it is- hotter air.
It’s why everyone uses scoops and not mini sized grill cracks to supply the 750-1500 cu.ft. of cool air flow required by the engine. And why the Camaro utilizes an air scoop in the grill. They are looking for cool outside air for their filter box.
Fact: Very little cool air finds it’s way through those little 50 CFM grill openings. Yes, some outside air mixes with all that hot air from the radiator, engine, headers etc. but it is all ingested via the filter into your engine.
Finally, under-hood shrouds and seals do virtually nothing. Once eliminated, this common but huge test misstep (we’ve seen up to 55 HP and 100* with hood “up” vs. “down”) the rest is common sense testing and the air and water data will support meaningful accurate results. All Kenne Bell kits mount the filter outside the engine bay where temps are cooler and consistent at any vehicle position or speed. The dyno fan will simulate vehicle high speed and under-hood air flow.
So, no exceptions. Locate the ambient temp sensor at the filter whether it be under-hood (hood down) or behind the front bumper. Begin test at the same temp or data is junk.
2) AMBIENT TEMP- Cool outside the engine bay air is what also cools the fluid in the heat exchanger. Cooler air= cooler water= cooler supercharger air into the intercooler= cooler air charge to engine= more boost= higher HP. So, ambient air temp should be the same as it influences all the other components. 20* higher ambient raises intercooler air and water temps. It does matter.
3) ACTUAL BOOST- Boost makes HP, but it produces heat. There’s no free ride. Twin Screw positive displacement, and centrifugal superchargers generate approximately 10* of charge temp per PSI. Starting run design temps are approx. 10* per PSI + Inlet temp. Example: 90* ambient + 90* (9 PSI) = min air charge temp 180* before intercooler. Roots style are higher. Be sure “actual” boost is the same. Don’t just assume all 9 PSI kits develop exactly the same boost. The intercooler system (air to water or air to air) is typically 50-75% efficient depending on numerous kit design variables. To accurately compare kits, boost cannot vary.
4) RPM, LENGTH OF RUN & GEAR RATIO- The higher the RPM, read end or trans. gears the longer the dyno run and the greater the final temp. Everything heats up with time until there is stabilization. Use the same vehicle to insure accuracy.
5) STARTING INTERCOOLER WATER TEMP- If the intercooler water ( it cools the air) is 20* hotter at the “start” of the run, the “finish” will be hotter. Start temps must be identical for accurate comparisons.
6) STARTING INLET AIR TEMP- Same here. Obviously, a hotter filter at the beginning of a run results in higher supercharger discharge temps. A 30-50* variance is common. Start test at same filter air temp. or the tests are useless. NOTE: Under-hood filters are difficult to test because engine bay temps increase (heat soak) with time when idling. Open the hood and let cooler dyno room external air blow in and the test are skewed.
7) WATER VS. COOLANT- Since no liquid cools better than water, 100% water is best. 50/50 is not as efficient in cooling. 90/10 is better. Try placing ice cubes in a pot of coolant. Ice 32* and coolant 50* between the ice cubes. Engine coolant “resists” lower temperatures and freezing. Run the same mix when testing if your goal is an accurate comparison.
8) SUPERCHARGER TEMP (HEAT SOAKING)- Obviously, heat soaked components can heat the air passing through them. For example: We use a thermal laser gun to quickly measure supercharger case temp. If the supercharger is covered (never on our design priority list) with a manifold, intercooler or plastic engine cover, it obviously runs hotter. Then there’s the heat transfer from the engine. However, for test comparisons, the temps. of the supercharger and other metal or plastic pieces in a particular kit “are what they are.”
9) INLET RESTRICTION- NEVER compare 2 kits with inlet tracts ( filter, meter, tubing, throttle body etc.) that vary in restriction/efficiency. If one inlet is larger and enjoys less restriction to air flow to the supercharger, then the supercharger is not required to work as hard. Like sucking coke through a straw vs. a straw half pinched off. The upside of a larger inlet tract is the supercharger uses less HP to suck in the air and subsequently runs cooler AND develops more boost. Supercharging efficiency, boost and inlet temps will all be better but DIFFERENT.
10) IDLE/RUN-AFTER RUN- Idle temp. will be highest before a run. Let it cool to the test temp. and make the run in the same gear, car, boost, trans. and RPM. Check the data at the same peak RPM as everything heats up after getting off the throttle.
11) WHERE THE ACTUAL CHARGE TEMP MEASUREMENTS IS TAKEN- This is probably the most important part of the measurement process. Equally important is the sensor being used is properly calibrated. Different air temp sensors can be calibrated differently and if the person testing is not aware of this, all data will be useless. Transfer functions are different for some push in type sensors vs screw in type and vs shielded/unshielded sensors. The most accurate and fastest response air temperature sensors are the unshielded type. Never compare shielded sensors against unshielded.
Given that the a) sensor types are the same (unshielded) and b) the transfer functions are correct, then c) placement of the sensor is critical. Let’s make sure we are not using a sensor that is located upstream of the supercharger on one system and then downstream on the other. Believe it or not this mistake has been made before. Whenever temperature readings are only a few degrees above ambient under boost, always suspect the sensor is either a) located upstream (before) the supercharger as is the case in many applications if a new sensor has not been relocated from the factory location to the discharge side of the intercooler, or b) sensor is incorrectly calibrated or c) sensor is of the shielded type. Ever wonder why there are sensor “relocation kits?” was it the wrong location?
12) IMPROPER CIRCULATION (AIR TO WATER)- Always compare systems that have proper water circulation. A common error when seeing high discharge air temps is not to insure there is adequate flow in the system. In any new installation it is very easy to have air pockets that hinder/stop circulation of the liquid (cooling media). Even the best designed system can produce high charge temperatures if proper purging of the intercooler system has not been performed. Blockage of airflow to the heat exchanger from debris, bumper cover, etc. can also have a drastic effect. There has to be sufficient airflow across the heat exchanger to drop the charge temperature.

In conclusion, what we often think is the same is the same but it’s different.
If analyzing supercharger kits by the same or competing manufacturers, it is important to refer to the above 12 test variables and make the necessary adjustments to guarantee boost temperatures, run length, inlet, restriction, temps measurement location is identical- and the hood is CLOSED, like you drive the car .
There’s a saying on the Kenne Bell dyno that an OEM engineer left us- “One of the real dangers in running a test is you are bound to get data”.
We hope the information is helpful.

Matt, that is some great info on proper testing!
thanks for sharing...

with that info, maybe you could answer my question about the effects of HIGH IAT's.
i know my chart was elementry but maybe you can shed some light on the issues or lack there of when the IAT's start to rise...
i know you guys are sitting on boxes and boxes of test results.
maybe crack one of them open for us?

[mikepage0007]

Originally Posted by old motorhead

How much boost used and hp made on these runs. Unless I'm reading the graphs wrong, IAT's at the start of the run were 45 over ambient and ended up over 65 above ambient. Is that right or am I reading it wrong?

good question, and would be interested to know how long cool down period between 2nd run...i do run my first run approx 45 degrees overambient , which puts me @ 140, and hit around 185-200iat in the 1/4.problem is car will not be at 140 for the next run unless it sits for an hour..totally heatsoaked..i have never seen a kb make a dyno run under 150f

[Supercharged SS]

Even being heatsoaked my IAT's seem to cap out around 90 degrees celcius. About 15 degrees celcius less with the ice cooler in the stagging lane for 45 minutes.

[JANNETTYRACING]

Originally Posted by Supercharged SS

Even being heatsoaked my IAT's seem to cap out around 90 degrees celcius. About 15 degrees celcius less with the ice cooler in the stagging lane for 45 minutes.

Yes but this is 17 psi boost not 9 psi boost.

[mikepage0007]

Originally Posted by Supercharged SS

Even being heatsoaked my IAT's seem to cap out around 90 degrees celcius. About 15 degrees celcius less with the ice cooler in the stagging lane for 45 minutes.

which is around 194, only tuners get to use celcius..conversion guide for us rookies...http://www.wbuf.noaa.gov/tempfc.htm 167 with the ice...thats a 27 degree diff..not to bad..and which is it, jamie...18psi like under your build or 17 like ted said...lets get them stories straight

[Caliman93230]

I have not logged the temps on my whipple but I make multiple runs and after riding the whipple is still warm to the touch. There is very little jeat soak.

[mikepage0007]

Originally Posted by Caliman93230

I have not logged the temps on my whipple but I make multiple runs and after riding the whipple is still warm to the touch. There is very little jeat soak.

unforunately your air thru the manifold is what really needs to be read with a gauge ..no touch feely gauge..

[Matt@KB]

Jim Bell here. I checked out the thread. All good stuff. I believe Ford looked at the concept a few years ago. They thought it worked. Whether it be the chiller or ice water - or water injection, the cooler air will reduce the detonation threshold and permit higher boost levels, more spark and leaner (optimum) air fuel ratios.

We've done testing on air to air, air to water and ice water but never freon. Looks like a good approach. One test that really worked on our 7 second air to water Buick V6 Regal in 1995 was Syltherm, a hi-tech heat transfer fluid produced by DOW. I had encased my huge air to air intercooler core in liquid tanks/boxes containing the Syltherm. I called it the Sub Zero Intercooler. The stuff was incredible as a heat transfer fluid. It was rated at -100 degrees F, but the flash-point was only 145 degrees F. The problem was it was so cold it cracked the intercooler tanks and there was frost build up on the lines to the rear trunk reservoir. Understandably, that made our driver nervous about the condensation under the tires. Not good. But it worked. Still the only non-NOS 276" Buick single turbo to run 7's. Some of our Mammoth 2.8 and 3.6 Camaro racers are using ice water. Freon may be a better alternative.

Testing - I would not look for any substantial HP increases from the cooler air charge alone. The gains will come from the engine being able to handle the additional boost and spark with the same octane and not from the cooler air itself. Just like alcohol/water injection systems.

Good luck on the Freon.

Give me a call sometime and we'll talk.

Originally Posted by SC2150

Matt,have you followed our RX Spuer Chiller thread and the results on a Mammoth KB application?
http://www.camaro5.com/forums/showth...=99515&page=13

[Matt@KB]

Ted, you are correct. When purchasing - or testing - a SC kit there are issues - and misconceptions that should be cleared up. Here's one of them.

I totally disagree with your explanation 1. The number of oxygen molecules is NOT reduced as IAT temps increase. You are at the wrong end of the supercharger for that theory to be valid. That's a big common misconception in the industry. Our extensive testing of GM, Ford, Dodge and Mazda with various publications clearly proves it. Here's an example that may help you better understand what really occurs.

Heating or cooling the air AFTER the supercharger with the HE or IC does not and cannot increase or decrease molecules as you claim. The increase must instead originate at the intake (filter) side of the kit and not the discharge side of the supercharger.

Try this example: Supercharger rotates and discharges 2.8L of air into a jar and you seal it up. The jar can be heated in an oven or chilled in a freezer. I can assume that no "new" oxygen molecules will magically enter or exit the jar. Therefore, there is no possible way to increase HP by these new oxygen molecules you mention mixing with more fuel and making more HP. There are none. Now dump the jar into the intercooler. Where can the the new molecules come from? There are none.

Another big example is with same boost on intercooled and non intercooled kits. HP will be the same. Hard to believe? This one may create some discussion. Here too, there are NO new O2 molecules. Just a supercharger pumping a fixed CFM of air - and O2 molecules - into an engine. The SC doesn't know there's an intercooler. No new O2 - no increase in HP (there is one exception but it isn't related to molecules). Now cool the inlet temp into the SC with cooler denser air, which DOES contain more oxygen molecules, and we all know the results of the cooler ambient - more HP. Approx. 1% per 10 degrees.

That is why KB is so hung up on a big inlet system like our 4.5" Mammoth that supplies the SC with ONLY unrestricted cool external dense air (with more O2 molecules). No, hot underhood air does equate to higher oxygen molecule count. And it's why Tuners should never test with the hood open if your goal is meaningful real world test conditions.

Hope this helps.

Originally Posted by JANNETTYRACING

It is way more complicated than this due to all the different combinations of Boost, compression, octane etc.

A simple explanation is this;

As Air Temp rises 4 things happen;

1) Air Density or number of oxygen molecules is reduced, the result you can't burn as much fuel so therefor you make less power.

2) The timing advance needed to complete the burn is LESS, hotter Air/Fuel mixture burns quicker.

3) The chance of the Air fuel mixture Pre igniting goes up exponentially, this means the air fuel will either ignite on its own or burn too quickly causing Detonation.

4) Pre ignition or Detonation occurs and Knock sensors pick this up and try to control it by removing timing lead.

Ted.

[JANNETTYRACING]

Originally Posted by Matt@KB

Ted, you are correct. When purchasing - or testing - a SC kit there are issues - and misconceptions that should be cleared up. Here's one of them.

I totally disagree with your explanation 1. The number of oxygen molecules is NOT reduced as IAT temps increase. You are at the wrong end of the supercharger for that theory to be valid. That's a big common misconception in the industry. Our extensive testing of GM, Ford, Dodge and Mazda with various publications clearly proves it. Here's an example that may help you better understand what really occurs.

Heating or cooling the air AFTER the supercharger with the HE or IC does not and cannot increase or decrease molecules as you claim. The increase must instead originate at the intake (filter) side of the kit and not the discharge side of the supercharger.

Try this example: Supercharger rotates and discharges 2.8L of air into a jar and you seal it up. The jar can be heated in an oven or chilled in a freezer. I can assume that no "new" oxygen molecules will magically enter or exit the jar. Therefore, there is no possible way to increase HP by these new oxygen molecules you mention mixing with more fuel and making more HP. There are none. Now dump the jar into the intercooler. Where can the the new molecules come from? There are none.

Another big example is with same boost on intercooled and non intercooled kits. HP will be the same. Hard to believe? This one may create some discussion. Here too, there are NO new O2 molecules. Just a supercharger pumping a fixed CFM of air - and O2 molecules - into an engine. The SC doesn't know there's an intercooler. No new O2 - no increase in HP (there is one exception but it isn't related to molecules). Now cool the inlet temp into the SC with cooler denser air, which DOES contain more oxygen molecules, and we all know the results of the cooler ambient - more HP. Approx. 1% per 10 degrees.

That is why KB is so hung up on a big inlet system like our 4.5" Mammoth that supplies the SC with ONLY unrestricted cool external dense air (with more O2 molecules). No, hot underhood air does equate to higher oxygen molecule count. And it's why Tuners should never test with the hood open if your goal is meaningful real world test conditions.

Hope this helps.

You Are correct on Item 1, I had not thought it through when I posted, I was just thinking air density in general and not once trapped in the supercharger manifold.

Respectfully Agree.

Ted.

[HumanWiki]

Originally Posted by Matt@KB

Ted, you are correct. When purchasing - or testing - a SC kit there are issues - and misconceptions that should be cleared up. Here's one of them.

I totally disagree with your explanation 1. The number of oxygen molecules is NOT reduced as IAT temps increase. You are at the wrong end of the supercharger for that theory to be valid. That's a big common misconception in the industry. Our extensive testing of GM, Ford, Dodge and Mazda with various publications clearly proves it. Here's an example that may help you better understand what really occurs.

Heating or cooling the air AFTER the supercharger with the HE or IC does not and cannot increase or decrease molecules as you claim. The increase must instead originate at the intake (filter) side of the kit and not the discharge side of the supercharger.

Try this example: Supercharger rotates and discharges 2.8L of air into a jar and you seal it up. The jar can be heated in an oven or chilled in a freezer. I can assume that no "new" oxygen molecules will magically enter or exit the jar. Therefore, there is no possible way to increase HP by these new oxygen molecules you mention mixing with more fuel and making more HP. There are none. Now dump the jar into the intercooler. Where can the the new molecules come from? There are none.

Another big example is with same boost on intercooled and non intercooled kits. HP will be the same. Hard to believe? This one may create some discussion. Here too, there are NO new O2 molecules. Just a supercharger pumping a fixed CFM of air - and O2 molecules - into an engine. The SC doesn't know there's an intercooler. No new O2 - no increase in HP (there is one exception but it isn't related to molecules). Now cool the inlet temp into the SC with cooler denser air, which DOES contain more oxygen molecules, and we all know the results of the cooler ambient - more HP. Approx. 1% per 10 degrees.

That is why KB is so hung up on a big inlet system like our 4.5" Mammoth that supplies the SC with ONLY unrestricted cool external dense air (with more O2 molecules). No, hot underhood air does equate to higher oxygen molecule count. And it's why Tuners should never test with the hood open if your goal is meaningful real world test conditions.

Hope this helps.

I'm curious how all that relates to places selling the larger H/Es for setups like yours, Maggie, etc.. If the amount of molecules remains unchanged after the S/C and the act of compressing the air is leading to an increase in temperature, would it then not be more worthwhile to simply try to cool the intake charge before the S/C as much as possible? That way, you have more molecules going in to the S/C at a lower temp to begin with and at a certain boost rating would still only be allowed to heat to a certain temperature? Assuming the boost amount and heat soak from engine hasn't changed and you've lowered the intake temps and increased the number of molecules, shouldn't that be just as effective, if not more?

For example, utilizing a thermoelectric cooler in the intake box or track to cool down the incoming air and allow for more of it to pass through the filter and maf? -- I have the CAI inc. sealed box that's insulated and mostly only allows air to pull from behind the headlight -- would it be worth something like a strong Peltier unit in there or inline in a tube before the box to help cool off the incoming charge? Or, maybe an A/C chilled radiator inside the track and a system set up for allowing the condensation to escape before entering the MAF?

I just see things like expensive aftermarket H/Es being created for the PD guys and from what you're saying, it sounds like it's more important for the intake charge than the compressed charge.

[JANNETTYRACING]

Originally Posted by HumanWiki

I'm curious how all that relates to places selling the larger H/Es for setups like yours, Maggie, etc.. If the amount of molecules remains unchanged after the S/C and the act of compressing the air is leading to an increase in temperature, would it then not be more worthwhile to simply try to cool the intake charge before the S/C as much as possible? That way, you have more molecules going in to the S/C at a lower temp to begin with and at a certain boost rating would still only be allowed to heat to a certain temperature? Assuming the boost amount and heat soak from engine hasn't changed and you've lowered the intake temps and increased the number of molecules, shouldn't that be just as effective, if not more?

For example, utilizing a thermoelectric cooler in the intake box or track to cool down the incoming air and allow for more of it to pass through the filter and maf? -- I have the CAI inc. sealed box that's insulated and mostly only allows air to pull from behind the headlight -- would it be worth something like a strong Peltier unit in there or inline in a tube before the box to help cool off the incoming charge? Or, maybe an A/C chilled radiator inside the track and a system set up for allowing the condensation to escape before entering the MAF?

I just see things like expensive aftermarket H/Es being created for the PD guys and from what you're saying, it sounds like it's more important for the intake charge than the compressed charge.

Oxygen molecules aside, Heated air entering the intake port increases the Burn speed and can also lead to Preignition.

This is the whole purpose of reducing IAT.