Strange dyno results - what's wrong??

[badboy]

Went for a new tune today. After porting the eaton, adding big SCT MAF, BAP and 6# lower with 3.1 upper, my power and torque went down!!???

With 2.8 upper, stock lower and stock eaton I was at 440 RWHP and 470 RWT. I thought for sure I would be around 500/500 with these new mods.

The A/F kept going lean above 5000 RPM in spite of tuner's efforts. Are the stock injectors the problem?? Stock injectors should be good for 500 hp, right? I'm running the BAP at 20% but we got the same results at different settings. We added timing but backed off when we got detonation at higher rpms.

Overall disappointing. Any ideas?

 

[badboy]

Another bit of data: The (Hilton)boost gauge pegs out at 16 psi really quick. Could I be seriously over spinning the eaton?

 

[combatstang]

sounds like its in the tune.

 

[AmazonTuning]

normally Id say when it goes lean up top like that you are pegging the MAF but since you have the SCTMAF but stock injectors ID say you need at least 55# on there..

 

[projekZERO]

probably the tune. or possibly the person doing the dyno wasnt getting in it.

last time i got my car dynoed i caught the guy taking it easy. he said he was all the way in it but i said look dude i was watching my boost gauge and it barely hit 10 psi.

needless to say the rest of the runs were alot higher and i watched my boost gauge hit 13 on all of them. not to mention i picked up 40hp, freakin liar.

drive your own car on the dyno if at all possible.

 

[combatstang]

drive your own car on the dyno if at all possible.

or go to a chevy shop to have your car run. They have nothing to gain if you dyno low.

 

[o3SnakeBite]

What were your numbers after the port and 6lb lower? I dont see where you posted it?

 

[badboy]

After the port, etc. we got about 430hp and 460tq. Lower than before. I'm thinking maybe the tune? Or what I don't know.

 

[707RIDAH]

.

Went for a new tune today. After porting the eaton, adding big SCT MAF, BAP and 6# lower with 3.1 upper, my power and torque went down!!???

With 2.8 upper, stock lower and stock eaton I was at 440 RWHP and 470 RWT. I thought for sure I would be around 500/500 with these new mods.

The A/F kept going lean above 5000 RPM in spite of tuner's efforts. Are the stock injectors the problem?? Stock injectors should be good for 500 hp, right? I'm running the BAP at 20% but we got the same results at different settings. We added timing but backed off when we got detonation at higher rpms.

Overall disappointing. Any ideas?

who did your tune?

 

[sambandit]

Dont fret man, it's in the tune. I have witnessed on the dyno, personally, a car pick up almost 50 hp from a tune. The first tune wasn't bad either, the A/F was nearly identical to the second tune, but the second tune made almost 50 more hp than the 1st. Get the tuned ironed out and you'll be OK!

 

[svtcobra0304]

strange indeed.

 

[badboy]

Another odd thing: I'm not sure how the BAP is supposed to work but when I increase the BAP setting, the whole A/F curve moves down (to the richer side) across the rpm range. But it still tails up above 5000 rpm, even with the higher BAP settings. Can anyone explain this to me?

 

[SA SNAKE]

Keep us posted on how you fix this problem. Good luck.

 

[predator]

normally Id say when it goes lean up top like that you are pegging the MAF but since you have the SCTMAF but stock injectors ID say you need at least 55# on there..

I would have to agree. I watched a car tuned recently that had the same symptoms you are describing. It was not getting enough fuel. Needed more injector.

 

[fast1]

probably the tune. or possibly the person doing the dyno wasnt getting in it.

last time i got my car dynoed i caught the guy taking it easy. he said he was all the way in it but i said look dude i was watching my boost gauge and it barely hit 10 psi.

needless to say the rest of the runs were alot higher and i watched my boost gauge hit 13 on all of them. not to mention i picked up 40hp, freakin liar.

drive your own car on the dyno if at all possible.

Why would the guy be taking it easy on the car?

 

[projekZERO]

Why would the guy be taking it easy on the car?

i have no idea, but i didnt pay $125 to get half ass results

 

[combatstang]

Why would the guy be taking it easy on the car?

To screw you on dyno time or cost for another tune. Go with RWTD and never look back.

 

[BuffDigits]

Ive just recently been in the same boat. Lots of mods, all good stuff, no power.
Its not injectors, maf, or the parts. It can be clogged cats, bad o2 sensor, bad tank of gas (more water in gas then normal), or the inevitable, crappy tune.

Been there seen that, you wont believe the improvement with the right tune.

 

[CobraBob]

I can attest to what you can gain or lose with a tune. At one point with a bad SCT tune I lost between 40-45 rwhp. It was super rich. I went back to my Diablo chip and gained it back. So work on the tune. And it certainly wouldn't be a bad idea to upgrade your injectors.

 

[Rwick7]

$125 for a dyno tune???

I think the tuner may be the problem.

Find a reputable SCT tuner in your area and get it fixed.