blk00ss

iTrader: (66)

Ok I am having a problem with a newly installed motor. Just recently got everything buttoned up on my LS2 404, and have put almost 800 miles on it. Guess I'll give the run down on the set-up. Patriot stage III heads, Pat G cam(253/257 .622/.621 111+2), FAST 92/92, Kooks 1 7/8"-2" headers, through a 4" mufflex cat back, racetronix 255 fuel pump and hotwire kit, 42lb green top injectors, ASP UD pulley,. All this is through a 6 speed, Moser 9" with 4.11's. I have not had the car on a dyno, but has been fully tuned on a wideband, and the AFR is 12.8-13.0.

Well the problem is this...the car drives and pulls fine, but the power just isnt there. Best time I have got out of it is a 7.7x&93mph. Thats what the damn car use to run when it was cam only. Last time the car was together with this same motor, it would go consistent 7.40's and even dip into the 30's. And at 98mph. The car is BARELY outrunning cam only camaro's and GTO's. The car is throwing a p0108 code, which I believe is a MAP sensor low or high voltage. Also the O2's werent reading like they were supposed to so I jsut swapped them out. Havent swapped the MAP sensor yet. But could I dont see me picking up 5mph from swapping that sensor out. Also the car has a bad stumble/hesitation at 1300 rpms when you try to accelerate.

I know this is a lot to read through, but I am at my wits end with this car...I know the car should be a little more powerful than it was last time, but its just not there...any help would be GREATLY appreciated. thanks!

redhotSS

iTrader: (1)

what compression are you at? maybe a slipping clutch? id get it on a dyno if it was mine

blk00ss

iTrader: (66)

I jsut havent had time to get on a dyno. Compression is right at 11-1. Maybe 10.8-1. And the clutch is not slipping. Last time it was together it only had Pacesetter headers, a smaller cam. The only thing I did different this time was using LS3 5 layer gaskets instead of the cometics that were on it last. So that might lower my compression by like .1 or .2. That shouldnt be enough to lose 5mph.

redhotSS

iTrader: (1)

that sucks man, i dont have any other ideas.

za355tx

iTrader: (108)

Best thing to do is get it to a dyno and let someone who really knows what they're doing tune it. I've known some guys pick up more than 50 rwhp just having someone else tune there car. Lloyd Elliott's old car (97 Trans am) made like 375 rwhp when he first got it going. That was with a dyno tune by the way. That car after Bryan Herter gave it a base tune made 414 rwhp, then Lloyd had Bryan Herter dyno tune it and it made 436 rwhp through a stalled auto with an 8.8 inch rear. It's all about tuning man.

blk00ss

iTrader: (66)

This is the same tuner I have always used. Last time he got the motor making 505 to the wheels. Through patriot heads! I don't believe anyone else could have made much more than that.

tripblackls1

iTrader: (11)

so you put a bigger cam in without getting it retuned???

that alone can impair your performance dramatically

get a tune and see what it does

Hamrdown

iTrader: (25)

If you had fully read the op he said it was tuned on wideband to get the air fuel ratio set. Not every car is dyno tuned. Although in this case I would suggest getting it on the dyno and running a scan tool to find the problem.

blk00ss

iTrader: (66)

Yes if you would have read the whole post you would see that it has been on the wideband on three different ocasions. I am trying to get a dyno appointment, but people around here dont like business obviously.

tripblackls1

iTrader: (11)

a tune on a wideband doesn't mean crap just because your afr is in the right area does not mean your car is been tuned for its potential
because there is a lot more parameters to a tune then just its afr

and no not every car is dyno tuned but if you have more mods then just bolt ons (ie cam etc....) then its really not smart to not have it on a dyno

to op try to figure you map code out(a problem with a map sensor with mess with a lot of things)
and get that thing on a dyno

ARCTIC '00

Thank you for explaining that to him.

O.P., get the darn car on a dyno and let a good tuner work his/her magic.

losiguy

iTrader: (7)

You are down on a lot of power without a full dyno tune by someone who knows what they are doing. If tuning was as easy as setting the AFR to be "close enough" dynotunes would cost $20 and anyone could do it.


Pay some good money for a reputable tuner to dyno tune the car and I'm willing to bet it will pick up a lot. FYI I would of aimed more towards 11.5:1 if you have 93 octane around you.

bjamick

iTrader: (31)

I know the tuner, he also tuned my car. He knows what he's doing, he's built a many cars that are just plain nasty. He can dyno tune any car, its just he can do a driveability tune right there on the street along with the WOT tune. He does it all using a wideband.

Make sure and check that all your plug wires are completely plugged in. I have one that keeps popping off a lil and causing the car to feel weak. I am still running the stockers though . Ya the 93mph is good for I guess 430rwhp or around there. Which is weak for a 404ci H/C motor. that car should be around 500rw with your setup. Maybe its just something a simply tune up may fix. How is your fuel pressure, maybe the pump is weak?

Have you changed fuel filter lately? What about your injectors, they are prob new anyways though? What about cleaning your MAF? If all else fails take it to Walkers dyno and get Marcus to look over the tune again while its on there.