airborne

Hey, if you install a new IC (going from stock to M2 large) do you need immediate tuning done? I mean will driving with the same map hurt anything? basically i'm thinking about installing the IC myself and driving it to be tuned. any harm in that?
thanks

cewrx7r1

iTrader: (2)

If you are running the same boost after the install as before, think about what the large IC will do.

In cold weather the air charge temp will be about the same. If you ever felt the stock outlet pipe and the new outlet pipe in cold weather, there isn't much difference. Cold weather power is the same. Why? The IC can not cool the charge colder than the ambient air temp. The air is already cold that the under hood temps are very low and same applies to the intake charge. The increased cooling capacity of the larger IC is not fully utilized when the air charge is already cold. Ever look at pictures of the size of WW2 aircraft ICs. For the engine size compared to ours, they are small. That is because where they operate (high altitudes) the air temps are way below freezing and a large IC is not needed. Same applies here.


The difference will be during hot weather when the larger IC's increased efficiency will work. This colder intake charge will allow more power to be made over the smaller IC due to the more condensed air, but still less power than in winter


Lets talk about fuel now. With our ecus which have poor air temperature control over fuel regulation, boost has more affect over fuel delivery. If the fuel is already set up for safe AFRs for winter, then they usually will be richer in summer. If I have an AFR of 11.0 in cold winter, for the same boost in hot summer it will be lower (richer) because the density of the air charge will be less which means less oxygen, but I have the same fuel delivery.

This extra fuel does have an advantage sometimes. If the IC does not keep the air charge cool enough, it becomes too hot and this can lead to detonation. The extra fuel helps to cool the charge and make it less explosive. That is why our small stock IC engines run so rich. It is a safety factor. A large IC gives an increased safety factor by cooling more and needing less fuel thus more power.

So now to your answer. You only need more fuel if you were running lean in the first place because you really have not changed the overall breathing capacity of the engine. You have only changed the charge density. Intakes, DP, MP, cat-backs, and porting are the changes that really affect breathing capacity.

Let the discussions and counter points begin!

KZ1

No, say it is 50F outside and you have small stock-mount. then your intake temps are at say 40C, or say it is 80F outside, and you haev huge FMIC so intake temps still 40C. no tunnign needed. It just amkes the car think it is colder outside (obviously not, but you get the point)

pressure drops, boost pressure that is diffent ballgame. You may have some tweaking to do there, but not any rocket science.

airborne

ahhhh...i understand says grasshopper.
thanks cewrx7r1 and kz1!

forcefed1

I come from the world of MAS air tuning. trying to thing in speed density takes a min. one question. where is the IAT sensor installed? after the intercooler?

now on to the way I understand this tuning thing.

ANY CHANGE IN THE VOLUMETRIC EFFICENCY REQUIRES CALIBRATION

In the case of the intercooler. The VE of the engine does not change much, not enough to bump you to a new map if in fact you are tuned well for the current map before the intercooler installation. What it will do is make the car run the way it would on a colder day on warmer days.

Also, changing the boost only requires you to change the maps in the high boost areas where you have not tuned before. after tuning there though no further change is needed.
But if you remove the CAT and restrictive muffler. and port the engine, you are now going to have a new VE for teh engine that your current maps will not operate within. Not for long.

Im not saying waht I have stated here is correct. Im asking if I understand it correctly.
Im assuming the IAT sensor is in the manifold after the intercooler

KZ1

map sensor is in intake sensor. however, the maps for PFC are set to cover high boost already. 17psi or something. so you shouldn;t have to do anything.

but yes, creating a more volatile and quicker burning mixture within the chamber requires that timing be retarded, etc. even with the correct a/f ratio

adax

iTrader: (2)

This weekend I added my CWR intercooler (from stock IC) to the following mods I had been running with: intake, street port, downpipe, midpipe, catback. Previously, I was running 11 PSI which the PFC held steady to redline. The IC is the only thing I changed affecting airflow into or out-of the engine. Now, I have 12 PSI which creeps uncontrollably in anything higher than 3rd gear and 6K RPM when using the previous boost settings.

This tells me that the IC does more than affect intake temps. As forcefed 1 stated, it would appear that it changed the VE of the engine: at the same MAP, airflow has been increased as indirectly proven by the inability of previous boost settings to control boost. This would mean that the maps may need to be changed to achieve the previous AFR.

Yes, the intake temp sensor is in the intake manifold, where it gets heat soaked.

Alan

Scott Olsen

The reason that adding an intercooler increases the VE is because of pressure drop. The intercooler you added most likely has less pressure drop than stock. This means that the turbos don't have to work as hard to produce the same amount of boost at the manifold. When your turbos aren't working as hard, they are restricting the exhaust less, therefore increasing the VE.

adax

iTrader: (2)

Wasn't that what I said?

Can't read A/F from the commander.

Alan

airborne

Sorry to resurrect a dead thread but wanted to say thanks again to the informed advice here. Since I asked this question way back when, I got a small pettit IC and had the car tuned by Steve Kan. Now, finally, I'm upgrading to the ASP large intercooler. I was searching for what tuning may need to be done and found this old thread.

Looking back what I get out of it is: you don't *need* to retune after upgrading your IC but you may be able to optimize the tuning for more power. Since the power fc is controlling boost and accounting for intake temp, the variables a new IC changes seem to be covered.