Mbueno

I recently dynoed (dynojet) my full bolt on A4 ls1 and i got really low numbers on it.... I made 268 rwhp for some reason when i was dynoing 290rwhp stock..... The tuner said that since my air to fuel ratio was very lean, it was causing me to dyno so much less.... When he was dynoing it was reading about a 15.5 AFR.... So i was wondering, does this really rob all the power? I have always read that full bolt on A4 ls1's make around 330-340 rwhp.

I'm at 4,000 elevation and run 13.5s (stock ls1's runs high 14s).... Humidity for the day it was dynoed was 20% and the temperature was 60 degrees...

So does running that lean really hurt horsepower by that much? He told me that by tuning it, it would help out alot.... I also have a predator tune on it right now so i don't know if that is affecting anything..... But a 15.5 AFR from what i have understood is bad.... He told me it should be around 13.0

outkast6991

iTrader: (34)

Ditch the predator tune. 15.5 is way to lean for wot

Mike@Diablosport

iTrader: (2)

What bolt ons exactly?

I have lots of customers running our canned tune on bolt on LS1s and they are nowhere near 15:1, including my 99 Z28 with Mac mid lengths, LS6 intake, LS6 cam, lid, etc.

Mbueno

The bolt ons are slp air lid, smooth bellows, ls6 intake, ftra, longtubes with ORY pipe, lm1, kn air filter.... thats probably all that would effect the AFR..... I'm going to restore the orignal backup and see if that'll make a difference....

flame

iTrader: (13)

Make sure your MAF is clean

Mbueno

Ill clean it.... hopefully thatll help... idk why its dynoing so low....

Old Geezer

iTrader: (3)

And, the fuel psi is, when doing the pull[s]??

Mbueno

I'm going to check the fuel pressure today.... I wasn't paying attention to that part, mostly the running lean condition.... Im sure it's alright, the tuner would have pointed it out... but you never know, especially around were i live where its hard to find any good tuners.

RevGTO

iTrader: (12)

I have had a lean condition at WOT above 4500 rpm. Finally got it on a dyno with a fuel pressure gauge and it my fuel pressure dropped off radically at that point, creating the lean condition. The dyno also show low hp numbers for the same reason.

Mbueno

Oh okay thanks for the input. Then I'm definitely going to check the fuel pressure at WOT.... and how were you able to fix this revgto? I'm guessing the dyno is suppose to show the fuel pressure? I'm new to this tuning so please bare with me lol.

Old Geezer

iTrader: (3)

"I'm guessing the dyno is suppose to show the fuel pressure?"

One would think so, given the results of the pull[s] made...
Way too many "tuners" are doing just that, "tuning". No t/s, should issues arise, nor suggestions as to what the problems may be.
Dyno run/LEAN/ thanks for the $500. When you get it fixed, bring it back, and we'll be most happy to take another $500.

Mbueno

Ah okay, see that's the problem with the shops around here.... but he probably still has my file on the pulls though... ill go by next time to check it out. He told me he was able to adjust everything when he does the tune. I also have a open cutout as well but even when it was closed it was still reading a bad afr. He told me to go get the exhuast leaks fixed and to also make an o2 bung right in the the y pipe, that way no exhaust leaks would affect anything and he would be able to do a tune on it that'll fix everything.... I'm going to do a cam swap and stall in a couple of months so I am going to ask if I would get a discount on the tune if I go back.... for now ill change the plugs and clean the maf. Ill probably go back within the next week and have them tune it. I only payed 80 for three pulls so it wasn't too bad. Since he has already acquired the license on ls1 cars he will charge me $350 for the full tune and fixing everything. Other shops around here want to charge me the cost to get ls1's license's for their hp tuners and the tune.....

Slowhawk

iTrader: (12)

You can't blame the dyno's you just ran your car on for anything.

You just need to do some work like clean the maf and check fuel pressure. Then you should work on the tune. Pretty normal thing for these cars.

We've tuned over 1k cars. I garrenty no 2 cars have the same tune. So,correct tuning will definitely benefit your car.

Mirko76

You can't blame the dyno's you just ran your car on for anything.

Mbueno

Checked the fuel pressure today and it was a solid 60 thoughout all the rpms..... I cleaned the maf sensor as well and it was pretty dirty.... so hopefully it was just the maf sensor then..... could a loss of compression be the problem?

Mbueno

Sorry for double posting.... I think I may have found the problem.... I feel so stupid now haha.... so last night I sold my catalytic convertors that were laying around for about 9 months..... but when I was looking at the pictures of them this morning I realized something.... the front o2's are not the ones connected in the longtubes I have lol.... I checked under the car and the ones that are connected are the rear o2's..... and the front o2s connectors is just dangling there. Wow I feel so stupid right now as I ran the car about 9 months like that. Now that I may have found the problem... which o2 sensors do you recommend?

97camaroguy

iTrader: (5)

^ lol this ******* guy!
Glad you figured out the problem.
I use these O2 sensors: GM #19178930 AC-Delco AFS75

casias

iTrader: (1)

I think I would find a different tuner next time. That should have been an easy spot by someone who is supposed to make your car run better.

bayer-z28

iTrader: (14)

Glad you got it squared away.... Now take a ride up to TSP and have them tune it. It's a ride from ELP, but still worth it. They tuned mine in 2008.

Mbueno

Okay thanks... and yeah its like a 5 hour drive around there.... worth it a lot.... I might take a couple buddies up there if we plan to go. Work is being a b**** right now though lol. Going to do a compression test just to make sure everythings working properly; while I'm fixing and checking everything now.