allmotor_2000

Okay folks, here's a tip for my fellow CL-enthusiasts.

As you all know intake air temperature greatly affects engine performance. Around a 3-5 degree increase in the charge temp effectively reduces air density by about 1%. This means the ECU puts out less fuel per declining O2 content. A very easy way to
gain a few ponies on your motor is to do the following:

(1) Buy 4 extra TB gaskets (its around $1.00 / gasket)
(2) Remove the throttle-body
(3) Re-route the throttle-body coolant hoses so that they DON'T pass through the throttle-body
(4) Replace the TB with a total of 5 gaskets (most likely the original gasket won't break)

This will drop your IAT by about 35 degrees under most circumstances... under WOT the throttle-body generally runs a tad cooler.

If you have a CAI, performance gains will be even better.

I don't have dyno-proof, but it works... if you want to take my word on it!

Zapata

What's the down side??

Nashua_Night_Hawk

A mod that might works for the people in the south... we risk a lot of problems here in the north... Another mod, is water wetter and low temp thermo.

allmotor_2000

Your idle-air-control might act a little wierd... no check lights or anything like that. You probably won't have that 1500 RPM idle during warm-up.

Zapata

I'll pass Thanks for the tip!

allmotor_2000

This won't have any risk as its not like it doesn't allow it to heat up at all... just lowering it a tad bit!

This will just complement the water-wetter and low-temp thermostat/fan-switch.

Zapata

Yeah might be a "summer" mod. With temps going into the teens during the fall and winter I need all the heat i can get.

SilverKnight

Where to get the TB gaskets?

mattg

how do you re-route the TB coolant hose?

KavexTrax

i need a primer on internal combustion engine theory

Lost all of that knowledge since shop class in junior high.

allmotor_2000

Instead of running the coolant hoses THROUGH the TB...you bypass them using a $1.00 fitting (just couple the two together).

The TB gaskets can be purchased from acuraonlineautoparts or any other wholesale OEM parts distributor.

Juker008

How bout this. Reprograming the ECU to think that the ambient air temp is around 40oF all the time.

But let me ask u this. What is the perfect air/fuel ratio to achieve proper combustion and engine efficency? At idle I believe the car's ratio is 14.8 . So what would happen if the car were to generate a ratio of 15 all the time even in VTEC?

My dyno claimed that during VTEC the ratio was around 13.8 , I would guess that seems alittle RICH. What do u think?






Juker008

allmotor_2000

Fooling the ECU to think intake air-temp is colder is going to do you more harm than good because the intake air-temp need to be cooler for the extra fuel to do anything!!

scalbert

There are a couple of problem here.

First off there would not be a 35 degree drop in IAT readings. There is not enough surface area for the fast moving air to pick up that much heat. I have had my TB coolant lines bypassed for some time (no part is needed, just use the existing hoses and clamps) and have monitored the IAT value; it shows little to no difference. Maybe after sitting at idle for some time there might be a few degrees difference but at cruise and WOT situation, the rate of airflow does not allow for heat transfer through a flat surface like the TB.

Right now and before, during cruise and WOT situations, my IAT is at or near ambient. That is as good as it will get.

Secondly, even if there were a temperature delta, this would be minimal and at most 5 - 10 degree after having sat still at idle for some time. This would amount to maybe 1 - 2 HP max.

Now with that said, re-routing the TB coolant lines wouldn't hurt. It would not give anything appreciable but might slow heat soak while in the staging lanes. But when driving it will make no difference at all.

scalbert

For the ideal burn efficiency to reduce emissions, 14.7:1 is the stoichimetric ratio. This is the ratio for lowest emissions output for gasoline. However, it is not the ideal ratio for power.

Best power is achevied in the 12.5:1 to 13.0:1 range. I would guess that our cars would make the best power closer to the 13.0:1 range. So your 13.8:1 was a bit leaner than one might want for the best power.

scalbert

There would be more to this than that. We use a speed density system to determine load. Basically since the intake manifold is a fixed volume then by knowing the temperature and pressure you can calculate air density. This, along with other signals is used to determine engine load. Finally it would then determine the amount of fuel to inject.

By fooling the ECU into thinking the temperature was cooler than it is would cause the car to run richer which would most likely hurt power.

allmotor_2000

With 5 gaskets or some thicker material for a gasket that doesn't transfer heat as much would help make the TB run cooler. Agreed that just re-routing the coolant hoses wouldn't make much of a difference!

scalbert

The TB is only about 2 inches long; with airflow velocities of about 6 feet per second at WOT that leaves little time for heat transfer from the TB.

Keeping the TB cooler is good but IMO, only helps with heat soak when stopped. When at WOT there is little to no heat transfered to the air via the TB. The flow rates are too hight for the little surface area presented to the airflow.

allmotor_2000

How about the intake manifold then? Bigger job I suppose!

Juker008

Oppps. Sry I just checked the dyno chart and saw that in VTEC I was at 12.0 .

Is the only way to find out if leaning out the engine will produce more power, is to do it on a dyno?







Juker008

scalbert

Reliably, yes. You could purchase a wide band O2 monitoring system and make runs at a track. But the launch, traction and or weather conditions will also influence the results.

Another way would be to use the wide band system and an accurate acceleration system such as the Vericom 3000; but now you are in the hole about $3500 total for both the wide band and the Vericom. That $3500 can buy quite a few pulls on the rollers...

http://www.vericomcomputers.com/Products.htm

scalbert

You would need to disable the EGR system as that would pump more heat into the manifold. A phenolic gasket could be made for the manifold to injector base mating. That would help isolate the manifold from heat transfer from the heads. But I doubt much, if anything would be gained.

xenon7

scalbert,
I assume at this point adding an extra gasket or 2 under the
IMRC plate (sim to the TB mod allmotor was thinking) would yeild little to no HP increase by slightly raising volumetric capacity in the plenum.

scalbert

That is what my IMRC plate hoped to acheive but was unsuccesful:

xenon7

I Know man, I followed that whole thing- still looks damn good
from the pics!

I guess I was thinking more of what half of that alum plate thickness or even a 1/4 thickness in height would yeild.

very little I assume.

scalbert

I had thought about taking my plate to a mill and cutting it down in half; then re-test. But I lost interest after the first failure.

The problem with a larger gasket is that you lose to seal at the top then. A center channel would need to be used similar to what I did with that wall down the middle.

xenon7

I pulled my cover plate not to long ago to get a better view of the labrinth and I see your point in terms of sealing.

Milling that nice piece of alum might be key, but I understand the lack of intrest.

Any thoughts on increasing the distance on each of the 2 alum intake runners?

Tom2

No, not really. Using the proper resistor in the IAT connector lead will "fool" the ECU into thinking the temperature is cooler than it is and the ECU will respond by advancing the timing, which will result in more HP.

This is an old trick that Mustang owners have used for years now to advance their timing with a DIS system.

scalbert

The Mustangs use a MAF, hot wire anemometer or karmann vortex shedding device, either way they use a single sensor to directly measure mass air flow. The IAT was used to help determine timing and could be altered and gets more timing without affecting fueling.

We do NOT have a MAF, our load calculation is 95% based on the MAP and IAT; Speed Density. Alter the IAT and the perceived load will be changed. A 20% FS change in IAT value could result in a 5% - 10% in the fuel supply. Any possible gain from two to three degrees more timing would be offset by the overly rich condition.

Yes, the IAT will influence timing. But it appears that our ECU uses the ECT more for base ignition timing than the IAT. The IAT is primarily used for load calculation and subsequently fuel supply.

What works on other vehicles may not apply to others. The systems have to operate similar enough and use the same technologies for alterations to be applicable. In this case the two vehicles use significantly different load determination technologies.

I was curious about whether or not we could fool the ECU into thinking it was cooler. When I was on the dyno last December I tried out a box I made. This box had two potentiometers, one adjusted the IAT signal to the ECU and the other adjusted the MAP. Without adjusting the MAP signal and dropping the IAT reading thirty degrees the fuel trim adjusted about 2.5% - 3%. I then used the other pot to bring it back.

On the dyno I was never able to gain power. The best I could achieve was a loss of a couple HP; the worst was a loss of 25 HP. So no, our cars do not benefit from a simple IAT modification as the fueling is too dependant on it. Had I taken the time to thoroughly tune the MAP signal against the IAT then there might have been a little to gain. But in no way would a resistor in line with the IAT signal give any noticeable power; it could possibly lose power.

moomaster_99

Get a thicker(?) head gasket and raise the compression on the sucker!!!

scalbert

That would lower the CR. By using a thinner gasket or milling down the heads will raise the CR.

allmotor_2000

You mean get a THINNER head gasket and raise the compression....

moomaster_99

That's what i meant...

Juker008

Tom2,

That is exactly what I was thinking, that by tricking the ECU into thinking that it was cooler outside, that the timing would advance.




Scalbert,

Now u stated that by tricking the ECU into thinking that it were cooler outside than it really is, would make the car run richer. But wouldn't it also advance the timing to account for the additional fuel being delivered? If so could a VAFC be able to cut the additional fuel that wants to be sent but still keep the engine timing advanced?



moomaster_99,

don't i mean a "thinner" gasket?








Juker008

scalbert

Yes, it would advance the timing. I saw about 1 - 1.5 degrees more timing with the IAT readings adjusted by about 30 degrees F. This would amount to a few HP increase. But the fuel trim also started adjusting negatively (meaning that the car was seeing a rich condition).

What you get here is kind of a double strike against the potentials. With advanced timing come lower EGTs which is fine with the same A/F ratio. Now add more fuel to it and the burn would most likely get cooler; as you get to 12.0:1 and lower, power starts dropping off quicker than timing can give it back.

Things would be different if we did not use a speed density system; but that is what we have to work with. Yes, a VAFC could be used to correct for this and do well. But now you have to install a $300 device and tune it to gain about 5 - 7 HP between the lower seen temps and the tuned fuel curve.

I would love to see a simple solution, there just isn't one. I tried but that also did not work out. It would be nice if someone was reprogramming our ECUs and giving all the timing the engine can handle; but to date that has not occurred.

At this point I could care less about more timing, my supercharger is on the way...

allmotor_2000

Steve... you need LESS timing

By the way... let me know what the Comptech FPR sets the base-line fuel-pressure to... and what spring they have inside that thing. I got the universal one so it comes with two extra springs.

Thanks

scalbert

Gotcha, will do...

Wires

It'll be the same as the TB. Air is a good insulator. At WOT, there would be no change in performance by cooling the intake. If you ice it to make a drastic temp. drop, then maybe, but not 30 degrees.