Power loss at top end!!!

[2g2ner86]

First off this is what I have done to my car. 3" Thermal r&d catback, 3" punishment racing downpipe, ssautochrome header and o2 housing, fmic, greddy type-s bov, dual stage boost contorller, 255 walbro fuel pump. I just gasket matched the intake and exhaust ports on the head. I got on it for the first time in a while and the boost spooled up around 2500 rpm and pulled great untill about 3800 rpm. I was literally sitting in the car with it floored saying to myself "well this is boring" after 3800 rpm the car just doesn't seem to pull at all and this is in every gear but first. Any suggestions? Thank you... And I have search for those of you that like to say people don't search.

 

[pboglio]

Air/fuel/timing/compression.

Do a boost leak check.
Do a compression test.
Log ignition timing.
Log A/F ratios.

You will then find your answer.

 

[2g2ner86]

How do I log ignition timing and a/f ratios? I have a a/f ratio gauge. Sorry, I'm new to most of this.

 

[HazyViewz]

How do I log ignition timing and a/f ratios? I have a a/f ratio gauge. Sorry, I'm new to most of this.

You need to have a data logger ie: DSMLink or EMS.

Also if your cheap and dont intend on getting those, your ecu should be reflashable and you can use EvoScan i think to log some stuff. I never used anything but dsmlink so i could be wrong. But even with evoscan you have to have the obd2 adapter w/ io port then if you dont have the io you need io to usb.

EDIT: What kind of A/F gauge do you have? If its narrow band its next to useless. Not completely but with out a wideband its useless. So if you dont have the engine management or wideband you need to get on those.

 

[2g2ner86]

I don't have a wideband a/f gauge

 

[HazyViewz]

I don't have a wideband a/f gauge

Your going to need to get a wideband ( you can get a used for like 150 or so ) new at 200 on sale (various vendors here). An finally some kind of engine management. If you ever intend to add more go fast parts you might as well spring for DSMLink. (you need a laptop with that just fyi)


EDIT: Check your compression and do a boost leak test first before you start panicking about spending 200 on a Wideband and 600 some on DSMlink. It could be a boost leak.

 

[2g2ner86]

Boost leak tested and had one really small leak. I fixed it and the problem is still there. I'm goin to do a compression test next. I was also going to get the dsmlink but it was my understanding that you needed to have the EPROM ecu to connect it to. And I have a laptop so that's not a problem. And evenif I get the dsmlink, how is that going to help my problem, doesn't that just say to send more or less fuel to the motor?

 

[HazyViewz]

With DSMLink you can monitor everything and modify anything. Fuel,Timing Ect.

If you know how to tune, or know a buddy who is good at it, and get it tuned and your still having this issue then the next step is to open up the engine.

 

[pboglio]

You can get a baseline idea of a/f using the stock narrow band 02 and a cheap logger. If you have a grossly lean or rich situation that would even affect power, this will pick it up. The logger also would tell you what your ignition timing values are. Being a 2g, I'd bet the house the timing is the problem.

The logger is going to probably pick up the problem if it isn't a boost leak, or it might be an exhaust leak. Running seafoam treatment thru the motor is a good way of picking up exhaust leaks since it smokes so bad.

 

[turboboy4]

What turbo are you running? If you are running a t25 it falls on its face in higher rpm

 

[2g2ner86]

Yep. Running the t25 at 12psi. But honestly have had this problem before.

 

[2g2ner86]

Well I found out the problem. When I put the new timing belt on, the timing was retarded by two teeth. So I fixed that and now it's better. I'm still going to take everyones advice! Thanks everyone for your help!!

 

[HazyViewz]

Good stuff, good find. Let us know if and when you get the wideband and DSMLink

 

[2g2ner86]

Was looking into the dsmlink. Untill I drove home from work and spun a bearing =\