I am working on learning all of the ECU tuning stuff and so far so good. I recently change d out my Tomei 02 and DP (2.5 inch) for an Invidia02 and Helix DP, so now the whole post turbo stream is 3 inch.

I noticed right after the install that the car felt flat at WOT. I didn't think too much of it, because many years ago my WRX did the same thing until it got tuned. I got a big exhaust it actually got slower and pockey and then I got it tuned and it whipped into shape.

I figured the same thing is likely on the EVO. Not only did I go bigger, but I also changed the stock cat with a test pipe, so the thing can breath real easy.

At part throttle it pulls great, but as soon as it clicks into WOT the car goes flat ad weird. Is this expected? Does anyone have any experience with this behavior can tell me what the next most appropriate step is? I have Ecuflash, a JDMMAP sensor, and have logged a bit.

Is it logical to reason that the opening of the exhaust has messed with the stock tune of the car that it runs crappy at WOT? Or is this a sign of another problem.

Thanks for any help/comments.

M

 

possibly but I can't imagine by too much..You may be hitting about 10-15 higher load value and depending on whats in those higher cells for fuel and timing may cause you to hit knock or run a bit less timing resulting in less hp or a flat feel.

 

So far the ECU, or its maps are completely stock 9MR. I haven't changed anything yet. The learning curve requires patience, which is tough for me, but a good exercise.

It definitely ran stronger with the cat and the smaller exhaust (which seems weird), and I was trying to theorize how opening up the breathing on the exhaust end could make the ecu think something is wrong at WOT. Part throttle still pulls great.

Thanks for any input.

M

 

you'll never know without a datalogger..Great investment.

 

YUp, I am using evoscan and a laptop. Seems to work great, but I don't know exactly what I am looking for, or at least the reason it seems flat isn't jumping out at me with some graph or curve or drop in values. At least not yet.

Are you saying that you might expect to see timing being pulled, which I don't. Its only butt dyno that notices the flatness.

m

 

Does it feel like you are hitting a brick wall right when you get to pk tq? My guess is your hitting fuel cut. A tune will take care of that

 

hmmm, kind of. brick wall in the sense that its pulling and pulling through part throttle and then at WOT its just loud, but the pulling stopped. Almost like you popped out of gear, but without the mechanical part.

I should be able to see fuel cut in evoscan, correct? WOuld that be a duty cycle of 100% or close, and then to nothing?

 

Open your rom in ecuflash. Look at the boost limit table. Then look at a log. Look at the load in the logs and compare it to the boost limit.

 

I have done some tuning, basically to get the knock to 0 or 1s by pulling some timing.

The boost limit table has all 319s in it. Not sure if this is a remnant of the JDM map install or not. The load numbers in the logs seem to go higher than what I was expecting from my reading. Sometimes to 301 as a spike. Then other times at the expected 220 at WOT.

This is the pull with the burp in it, which I can't figure out. You can see the TPS dip down. My foot was burried.



Here is a pull showing the load and the boost limit table.





Any help or comments appreciated.

M

 

Clutch slipping?????

 

Aha, I didn't want to give it away, but yes it sometimes feels like that. Logic points to that, but some logic contradicts.

Before I changed the 02 housing and DP, no clutch slip (or none of that weird behavior). And, before I went to the JDM MAP setup no clutch slipping. The first WOT pulls with the new invidia 02 housing and DP gave me this weird sensation like huge timing being pulled. So I logged, but timing was as expected, then I logged the TPS. (cause I also had some weird issues at a smog check with the throttle, where it wouldnt' stay at 2500 RPM no matter what). I adjusted the throttle cable to allow for proper throttle control, then I saw the dip in the logs. weird. I was thinking its all the changes I had been making, but the behavior was clutchy.

I kept hoping for a ECU or other change to be the cause of the weirdness. I can also do the clutch test (handbrake and let out in first to stall, works as expected everytime).

have you seen that TPS behavior from clutch slipping cars, and why would the TPS do that? Also it doesn't log that dip all the time, but the sensation is pretty consistent.

Thanks for any input.
M

 

The INVIDIA O2 housing is garbage. Its been dynotested to subpar results against the ported and coated stock unit and Megan Racing tubular O2 housing that sells for $99.

You have made a poor choice swapping out the Tomei.

Sorry to break it to you.

 

If your rpm is climbing rapidly but your speed isn't then I would guess that it's your clutch slipping.

 

Some people says that when you're buying the Tomei Expreme setup, you're just paying for the name, but I guess you prove them wrong.

 

aaahhhrrrggg,
I tried to cross reference the choices before my purchase thoroughly, but at some point you have to actually do something besides thinking and thinking. So I got the invidia, because retailers told me it was the 'biggest' and or the best strength (because its cast). What they didn't tell me was how much of a PITA it would be to install. I removed the entire turbo to install the 02 housing, because of the lack of access to the nuts and bolts.

I felt that the power was down from the 2.5 tomei setup compared to the 3in invidia and helix setup, but thought it just needed to be tuned to handle the higher flow. Is that not a logical conclusion?

The tomei DP is only a 2.5 unit, so that 02 and DP need to go as a pair because of the flanges. (doesn't use the spring setup of the stock 02.

Butt dyno told me the car was down on power after the install, but I thought tuning would reap the gains.

M