I just got back from the dyno shop. Here are the results.
1st Pull- 274.4 HP, 314.4 torque
2nd Pull- 274.2 HP, 313 torque
3rd Pull- 274.4 HP, 314.4 torque
I am going to try to include links to the dyno graphs. The car is having some type of problem that I need some opinions on. The graph falls off and gets sort of choppy around 5200 on two of the pulls and I need to figure out why. The car just hasn't been feeling right here lately. The power is fine, but it seems to have some type of hesitation at times. I have a fairly new opti and the car only has 63,000 miles.
My only mods are: Moroso CAI, gutted cat and a flowmaster. It is an M6 car. Any help is appreciated.

http://www.villagephotos.com/viewpub...sp?id_=5489550
http://www.villagephotos.com/viewpub...sp?id_=5489585
http://www.villagephotos.com/viewpub...sp?id_=5489617
http://www.villagephotos.com/viewpub...sp?id_=5489659
The last link show the A/F ratio. It started out around 14.2 or so and ended up around 13.1 by the end.

 

nice numbers, considering the flowmaster and no headers.

 

Your car is running too lean. You should be approaching 13:1 from the richer side. I think you should address that first. It might be the cause, a lean mixture is hard to fire.....

 

Your #'s are pretty close to mine with almost the same mods. I have a little more hp but you have more torque. Did you notice a difference with the gutted cats?

 

Yes, the car is running lean. I thought about this, but I am not sure if it would cause the dyno graph to look this way. I am not sure how the car has gotten lean since I haven't really done any mods yet and I haven't had any tuning done. The car has some hesitation sometimes in the 2000-3000 rpm range. Sometimes it even feels like a miss, but I don't think it has a miss since the numbers it put down are fairly good. Anyone else have any ideas why the graphs look this way? The 2nd graph looks pretty good, but the other two don't look that great to me in the high rpm range.
Also, drewstealth- I don't remember getting much power gain from gutting the cat, but it has been done for several years so its really hard to recall for sure.

 

Plugs and wires if you haven't done it already...

 

If u can afford it, have a shop make you a straight pipe for $50 instead of gutting

 

May want to check your O2 sensors as I was having a close problem after header install.

 

I was just thinking that maybe you should get your car scanned to see if your seeing some knock. I know with the mods you have you shouldn't have any false knock, but i was with the mods i have. So i put some 100 octane in it to see if it was real or false and it was false knock. So installed a lt4 km. Maybe that is whats happening to you and its pulling timing. Just something to look into.

 

Your car has an ignition problem, or false knock. (again, ignition) That is indicated by the zig-zags in power on the graph. It isn't really that lean, especially considering the zig-zagging starts where it actually goes to 13, which is normal.

doodad, the PCM ignores the o2s at WOT.

 

Gotcha Ion thanks for the info. It was his later post about the lower rpm that caught my attention considering my recent problems. Speaking of which, did you get my email this week?

 

madwolf- thanks for the info. I was suspecting an ignition or electrical problem. I guess that I need to get in scanned and then go from there. Hopefully it won't be an opti because I just put this one on within the last 20,000 miles, but I can't see what else it would be. I changed the plugs/wires within the last 6 months. You can actually "feel" the car surge or 'miss' when driving it sometimes. Its not really missing, but it feels like that....like its cutting out I guess would be a good term to use. The surging happens more under light load(easy acceleration) than it does when going at WOT and is most noticable in the 2000-3000 rpm range.
EDIT: I don't know if "surge" was the proper word for me to use here.....maybe a hesitation is more accurate.

 

This might be dumb, but could MAF sensors cause a little lean condition? Since the air crossing the sensors isn't sensed as well, the car would think it's getting less air, so it gives it less fuel, hence a lean condition?

All I know is after I wiped off my MAF sensors with Electrical parts cleaner and a Q-tip the first time (very carefully), at about 55,000 miles, the car ran extremely smooth. I couldn't believe the difference. It also seemed to run a little richer after that.

Dan

 

i didnt know front o2s are ignored at WOT... (how does it set a/f if front o2s are ignored?)

get a lt4 KN... u might have false knock...

 

It doesn't set an A/F at wot. It uses the last known set of BLM's to determine a baseline and goes to the Power Enrichment tables where it adds/pulls fuel based on the settings.

I don't think it uses the MAF in PE mode either.