Hey all,

My friend has a 03 EVO, and just put an HKS downpipe on. Now it pulls nice and hard at 17 PSI, but when he cranks up the boost to 24, its "cuts-out" He used to boost to this before the DP no prob. Now with the DP he says its like it doesnt fire or get fuel for a second, then keeps going.

His other friend has the same car, gfot the same DP, and it does the SAME EXACT thing! Any suggestions?

 

From what I know the stock ecu will cut fuel at certain psi's of boost. If your friend is not using some kind of fuel management component perhaps this is the problem. With the new dp he's also probably flowing more air and perhaps runing more lean....

my .02
randy

 

I see what you are saying, but...

1.) he was able to boost 24 before the DP.
2.) He has an AFC, even tried turning up the fuel.
3.) This is the EXACT same thing that happened to his buddies EVO

 

I agree with nine4surfah, it sounds like fuel cut. You are pushing 1.65 bar with the stock ecu/fuel pump/injectors. You should definitely turn the peak boost down and look into remapping the ecu and uprating the fuel system if you want to boost that high.

You should run a quick search over at the MLR on fuel cut. They have been dealing with it for years and there are heaps of good tips on how to stop it.

 

if anyone has any more info on what is happening please post it as I am looking into purchasing the hks downpipe

 

ok.. i will tell him to look into that (he isnt a big computer guy, asks me to do this stuff for him)

The thing i dont understand is why he was able to boost 24 before the DP? Is he just reachin the high boost so much faster that teh ECU has a fit and it shuts it down?

 

The engine will flow more air with larger aftermarket exhaust pieces and intakes. The amount of airflow is one factor that goes into the factory ecu's determination of when to apply a fuel cut.

 

24 is WAY too much boost for pump gas. The down pipe allows for even MORE airflow. The Fuel cut is the cars LAST ditch effort to save the engine.

runs 20PSI, 21 MAX, that is it, he will make more power because I bet he is detonating so bad, which is why you get the cut along with no more fuel.

 

24 psi on a stock fuel system? what?

 

Has anyone actually logged injector duty cycles with various boost/afr levels. Noticed everyone is putting in larger injectors snd bigger fuel pumps. Any proof that the stock system sucks?

 

I dont think the stock system sucks. It just that when you increase boost, You will definitely need more fueling. Your evo 8s injectors are large enough and any increased boost on the stock turbo. The previous evo 5s and 6s needed larger injectors though.

 

Changy is right, the stock system certainly does not suck. I know that Claudius did a lot of research on fueling and duty cycle for his Evo6, he would be one guy to ask. Wish he still hung around here

 

::holds envelope with repair bill inside up to his head like Johnny Carson::

Parents bought him car, he watched fast&furious, bought MBC and cranked up the boost to "magically" make his car more powerful.

Typical 4G63 teenage owner that will blow up his engine at least once a year.

 

1.) he worked his *** off to climb up from the sales floor, to finance, to finance manager of a large car dealership. He puts in on average 9 hour days, while some end up being 12+

2.) He hates F&F as much as I do

3.) He was told my a performance shop that his car could do 24 with no problems. Needless to say he will never return to that shop again. (EDIT: That is if it IS NOT true that u can pull 24 on stock fuel system)

4.) He is closer to 30 than he is to a teenager.

5.) He has had many turbo project cars, this is the first time he purchased a OEM turbo'ed car. None of them have ever blown.

I dont think jay leno will be calling you any time soon to bring back any carson skits


To everyeone else, thanks for the responses. He is trying to track down a dyno with AWD capabilites to see what AFR he is running

 

Relax, chief. It's just funny reading your post acting like the DP is the reason there's something wrong with the car but oh yeah he has it cranked to 24psi. That's a triple spit-take.