Larger intercooler = running lean?

[m4drx]

i am running apexi now but i was running stock with this setup before. i have induction etc also as you have seen in my for sale thread. (you reaady to swap )

give me a call if you get any problems with your leak and other issues mate i have been there believe me.

[Jim_rx7]

ah, thought I recognised your name! ... lol.

I\'ll get the IC on tomorrow and will let you know with the induction kit as to how it fits.

[Jim_rx7]

I\'ve been speaking to some chaps over in the US about this and this is what was said.....

Larger intercooler generally does increase boost levels unless you have an adjustable boost controller to re-adjust it. The bigger flow paths cause lower restriction.

Also, the lower intake temps do increase the amount of oxygen reaching the engine. Although this isn\'t normally a problem for the stock ecu if your boost is tuned down to 10psi.


and....

Yes. If you boost above 11psi, I would install a boost controller (manual or electrical) even though you intend to buy a PFC later. The reason why is because the PFC\'s boost control is far inferior to a separate unit. If you\'re adding flow mods one at a time, it\'s reasonable to simply use your boost gauge for a before/after and stop when you go over 10psi. Usually the boost doesn\'t go up until you after install a couple of mods.

The whole thing about temps, sensors, and crap comes down to real-world practicality - someone went to the trouble of measuring AFRs and found that as long as you keep your boost at 10psi, your afrs stay safe on a stock ECU.

You can pretty much install any flow mods you want and set your boost at 10psi with an adjustable boost controller - with one exception. The exception is a fully decatted exhaust, which will often cause boost creep. Boost creep is beyond the ability of a boost controller, and if you read the FAQ or just google you can learn more about it. As long as you leave a cat in the exhaust, you have very little risk of seeing boost creep.

Dave

[Carl]

Hi Jim,
I just wish to point out a couple of things.
In aggreement with the USA adding a better intercooler does mean that the engine will run lean,as more air VOLUME will get into the engine by lower intake temps which increases the volume.The stock ECU will not see any need however to add more fuel,as it runs a fixed amount of fuel based on seeing Manifold air pressure(Map sensor) revs,throttle position, and to an extent air temps,water temps.Once over a certain threshold,the stock ECU just does not put more fuel in,stock boost with stock ancillaries is safe,maybe two mods such as decat and induction can be run and be still just ok,but no more.
As for the Apexi not being good at controlling boost,this is rubbish,they just like a boost controller work in the same way,and just like a boost controller need some time to setup properly.They have the same adjustments as a seperate boost controller,only on single turbo\'s do you need a stand alone controller.
The big advantage with the Apexi is that you can also change just about every other parameter needed to make more power too.
On stock fueling with your mods and decent mapping you should be able to make around 330 flywheel hp,which is75hp over stock!
You just cannot do that safely with a stock ECU and boost controller,just put the money for the boost controller towards the Apexi ECU,they are only around £360.00,which is incredibly good value for money.
Regards
Carl

[strange_days_uk]

you heard the man Jim !!!

[Jim_rx7]

Hi Jim,
I just wish to point out a couple of things.
In aggreement with the USA adding a better intercooler does mean that the engine will run lean,as more air VOLUME will get into the engine by lower intake temps which increases the volume.The stock ECU will not see any need however to add more fuel,as it runs a fixed amount of fuel based on seeing Manifold air pressure(Map sensor) revs,throttle position, and to an extent air temps,water temps.Once over a certain threshold,the stock ECU just does not put more fuel in,stock boost with stock ancillaries is safe,maybe two mods such as decat and induction can be run and be still just ok,but no more.
As for the Apexi not being good at controlling boost,this is rubbish,they just like a boost controller work in the same way,and just like a boost controller need some time to setup properly.They have the same adjustments as a seperate boost controller,only on single turbo\'s do you need a stand alone controller.
The big advantage with the Apexi is that you can also change just about every other parameter needed to make more power too.
On stock fueling with your mods and decent mapping you should be able to make around 330 flywheel hp,which is75hp over stock!
You just cannot do that safely with a stock ECU and boost controller,just put the money for the boost controller towards the Apexi ECU,they are only around £360.00,which is incredibly good value for money.
Regards
Carl

Carl, I tried to PM you, but your inbox is full!