htvette

iTrader: (1)

I just recently dyno tune after h/c, UD pulley and ls6 intake and got 412rwhp/360tq with afr 13. This is tune on a dynojet with EFI live, 28 degree timing. Base dyno with just LT was 330rwhp/320tq. These are PRC ls6 2.5 stg heads, TSP V2 cam (232/234). The car runs great but all this work and I gained 80hp and only 40tq (that's with pulley and ls6 intake). Please look at the graphs and tell me what is wrong. Thanks.

htvette

iTrader: (1)

BTW, this is on a 99 C5 cpe, 6sp

pdd

iTrader: (3)

what head gaskits? are the heads milled? what gears? vettes will dyno lower than fbody beacause of the IRS with everything else the same, but not that much

htvette

iTrader: (1)

I used new stock head gaskets. The heads are not milled and came with double valve springs. I have 4.10 gears.

eamador11

with stock 3.42 gears youd be 422 +/- gears causes the dyno to misread actual hp to the wheels.

Tq curve looks good for the street. did you do 30lb injectors?

if the car runs strong, thats all that matters. peak dyno numbers is just a guage to show you how much power you car can put down at 6800rpm.

ls1muscle

iTrader: (16)

What's the rest of the exhaust after the long tubes?

GuitsBoy

iTrader: (4)

The problem with not going back to the same dyno, is that no two read the same. From what I understand some of the new dynojets are reading lower numbers than older ones. Almost as bad as mustang dynos. Theres one by me that wont let me break 415 on. A few stock LS1s failed to get past ~280. Just one possibility.

htvette

iTrader: (1)

I used some cheap high flow cats and B&B catback exhaust. The baseline run was from another dynojet. What is the preferred timing for tuning?

GuitsBoy

iTrader: (4)

It varies a little depending on your setup, but lots of poeple run 28*, myself included. You have to see what she likes on the rollers.

htvette

iTrader: (1)

I spoke to TSP and they said this h/c setup usually nets a minimum of 380tq.

WS6TransAm01

iTrader: (13)

28degrees might be too much timing. These are not old school motors, very efficient combustion chambers like those on the LSx motors do not require high timing advance. But then again, it would only show up in crap times at the track, on the dyno it's supposed to show higher HP. The torque numbers are unusually low though.

Honestly I would not worry about it. I would go to the track. If you trap 115MPH something is wrong. But if you see a 120MPH or so then you're alright.

GuitsBoy

iTrader: (4)

What are you looking for us to tell you? The graph dosnt look like its peaking early or late, so the cam was likely installed correctly. Theyre good parts. Your AFR seems good and your timing is adequate. Try another dyno.

erikthegoalie

iTrader: (29)

a few things to consider here my friend, all is NOT lost!!! DO NOT think twice that you wasted your time...

Heads are heads, cams are cams, they WILL wake up your engine...sometimes howeverm unlocking that power is the trick...

First of all, like previously stated....

-4.10's rob HP and Tq
-IRS " " " "
-Dynos differ
-Cats, even though they are hi flo will cut HP as a lot of people who add performance parts !CATS (MOST not all)
-How free flowing is that cat back..remember, youve got A LOT more flow now..maybe its time to change that up a bit, let those headers do what they are designed to do...
-TUNE TUNE TUNE....I dont know who did your tune, but keep tweaking it...try different things like timing and all...see what it likes...you never know..
-And remeber, its the seat of your pants feeling of H/C that you worked hard for!

(this was all stated above, just wanted to lift spirits!)

htvette

iTrader: (1)

I will try another dyno. Seems strange that another dyno will give high results.
I was expecting and told by TSP that this setup will get 430.

GuitsBoy

iTrader: (4)

Like I was saying earlier, theres a dyno near my house thats about 20 HP lower than the dyno at vette doctors a few towns over. Both dynojets. Everyone lovingly refers to it as the heartbreak dyno. Its not uncommon.

htvette

iTrader: (1)

I will take out the cats and replace the fuel filter since it's over 60k old.

Pewterme

The torque numbers look low to me. I've got stock heads and injectors with no ud pulley and the 4:10 gears with a smaller cam. Not having the knowledge these fella's on here do, my only question would be if the cam was degreed. I originally made 356 rwtq before degreeing and then went to 382 afterwards.

htvette

iTrader: (1)

I did not degreed the cam. That's a noticeable difference. I will have it dyno tomorrow on the same baseline dyno before h/c to get a comparison.

ls1muscle

iTrader: (16)

Get rid of the cats and get a cutout, your numbers will change.

TOS98SS

iTrader: (2)

I think 80RWHP is pretty good for a h/c swap . You are only off 18 Hp from what TSP told you and you can't expect exact quotes . I would be happy with that and as other said try another dyno if you want a higher #