Dynoed my car this afternoon, surprised by the results and quite happy. I bought the car used and it came with a 1.1 bar tune, EVOMS air box, and a stock exhaust. I recently installed a AE Performance 3" race exhaust with no cats, x-pipe and mufflers. Sounds amazing and today's dyno results were impressive.

Couple of questions, the power seems quite good for a 1.1 bar tune on pump, I had though the turbos were stock K16's but now I'm not sure. They look like other K16's I've seen how different are the x50 turbos externally? Easy to tell the difference?

The other issue that arrived with the exhaust change is, quite often, but not always when going full throttle the car with stumble through about 1000 rpms or so and then clear up. Seeing the mixture from the dyno it's quite rich and I'm wondering if perhaps my ignition coils/plugs are not able to fire the mixture leading to this stumble. Seems to happen mostly at ~4k rpms. Never did it during the dyno pulls today though.

I did try disconnecting the battery over night to reset the PCM.

 

I don't think you've got stock K16s on there.

 

that stumble might be due to aging coil packs/spark plugs if you haven't changed them already.

 

if the car is stuttering between 4 and 5k then its your plugs and or coils.. usually plugs..
car is running low 10s afrs... thats way to rich... you should be around 11.7 to 12.2...
something is up.... I would get a durametric reader on it to check for codes...
I would also, when changing plugs do a boost leak test from the turbos up to 20 psi...
its like going to the doctor for a blood test...
markski

 

I have not changed the plugs since I have had the car. Was going to see if the local dealer has any 997 coils and put them in as well.

Bosch FR6LDC is what I was going to get, maybe gap them a bit less ~.032

I have a durametric, no codes all though sometimes it trips the rear o2 but I dont think that effects anything.

I agree on the mixture, car always ran flawless with the stock exhaust, wondering how much the catless 3" system is effecting it. Probably a decent amount of power in getting the mixture in line as well.

 

Hey good dyno numbers,,I think you might have K24s,X-50...Look under your front hood on the sticker options to see..

 

did you change the exhaust after you bought the car? if the tune doesn't have the cat bypass set up then that could be the reason why your running so rich... and that would explain why the OEM exhaust wasn't giving you issues...
we use denso plugs... not OEM

 

Perfect example of what happens when you SAE correct a turbo car at high elevation. Subtract 10% from your numbers and you'll be in the ballpark for true SAE conditions, right where a flashed K-16 + exhaust car should be on a dynojet.

 

Yes just installed the exhaust, same tune as it had, of which I dont know what shop originally installed it.

I think what I want is to have someone pull my tune (if thats possible) and modify it to run leaner. Based on durametric logs?

Going to try new plugs tomorrow, but I think it may be too rich.

 

so your issue is probably due to no cats... o2s are freaking out...
either run cats or you need a new tune... I knew something is up when I looked at your afrs... they slammed pig rich and that was the sign...
no tuner is going to do it.. I would not at least...
Mind you different tuners code differently .. some with o2s on. some without etc...
its more complicated then just pulling your tune and making a few adjustments...
you would need a new tune...
markski

 

You still made good HP/TQ for being that rich,,and the curve is good also,,IMO.......Just a stupid thought here,,, One time with my old muscle car that I had dynoed,the sniffer was bad and the AFR were showing rich also...Did you use a sniffer in both tail pipes??.......

 

Not sure why the rear o2's would freakout. Thought they were just there for obd-ii. The precat o2's are what the pcm uses no? Confused as others have said other then cel catless should be handled ok on a tune.

Pretty sure the dyno afr was accurate we dynoed a billet k16 right after and it seemed good and in the 11.5's

I suppose a durametric log would show the afr accurately?

 

You are going to have to explain this one. My understanding is a dynojet compensates for altitude. It's part of the Winpep software.

 

Basic: Does the exhaust rattle when the engine is cold and the car has sat overnight? I as well am running the same exhaust.

 

Very similar to my K24 runs years ago before going with Tials.

I had stock inter-coolers, exhaust and waste-gate upgrades and off the4 shelf GIAC K24 tune (pump gas) which really help in building and maintain boost IMO. You can see the difference in mid-range and top end power with the wategate springs.

From what I know, the dip is a 996 trait and it's the knock sensors pulling timing. It would very easy to see what's happening if you have logs.