Dutchesscamaro

iTrader: (1)

I currently have an APS TT on a C6 MM6.
The car had 4.10s prior to TT install.
All the ingredients are there for power.
spark is at ~16*
AFR at WOT is ~11.8
Manifold boost runs 6.5 basically flat from 2800 rpm
But he RWHP runs basically flat at around 400RWHP on a Dynodynamics.
What gives?

Engine is healthy
Compression test is ~205 # +/- 1%
Leakdown is 2%-3% all cylinders

IS 4.10s the issue?

Any suggestions?

Bob

HUNTER02SS

iTrader: (24)

I am not 100% sure that is all of your problem, but the gear's are not helping you at all!! I think you should have at least no higher than a 3.42! I have 3.23 and love them! The gear's are a good place to start.

echo3313

iTrader: (3)

those numbers make no sense but i agree with chris by saying those gears are no help...get some 3.42's

mahhddgtp

I have a hard time believing you're only making 400rwhp with 6.5psi on an LS2 motor.... Is the dyno messed up or something? Geez.

But yeah.. Those gears have got to go.

3.23
3.42
3.55's may not even be enough... I think it would be a tossup between 3.42s and 3.23s

Dutchesscamaro

iTrader: (1)

All you guys above; thanks for your responses.

On various boards I am getting mixed opinions. Some say that 4.10s will have no effect. I am leaning toward them having an effect on my problem.

thanks


Bob

Nmbr1GMfan

iTrader: (1)

Valvesprings... Although a higher numerical gear ratio will yield a lower dyno number it will be a mirror of another gear. Post your graph, if you see power level off and flatline, its springs.

mahhddgtp

4.10's definitely have an effect on the street.
I don't know what mind I was in earlier... I neglected to even think about valvesprings.

88blackgt

may not be THE issue, but it will certainly help it spool down low

chance575

should still be making more than that without valvesprings, i'm well over that mark with the stockers

HUNTER02SS

iTrader: (24)

I am just going to throw this out there! It is probably not what is wrong ,but did the tuner turn off the torque managment on you car?? I have heard that it will pull timing out when the car is under excessive torque. Like I said,probably not the problem you are having,might not have anything to do with it.Never hurt's to ask.

Dutchesscamaro

iTrader: (1)

Hunter
Thanks.

Torque management is off, timing was slowly raised until knock.

No resolution yet.

Bob

JL ws-6

iTrader: (50)

I'd put good $ that it's valvesprings. The gears aren't gonna do poo as far as what it makes for power or what it doesn't make... you have an issue in the tuning/engine dpeartment.

detroit_903

iTrader: (8)

I'm making over 400rwhp at 7psi with a stock lt1 engine and single rearmount turbo. Those dyno numbers were with 4:10 gears also on the mustang dyno. Over the summer I went with a 350 gear ratio and it made a huge difference -it allows the turbo to spool up and run into boost longer -

Dutchesscamaro

iTrader: (1)

t t t

Nmbr1GMfan

iTrader: (1)

Get off the computer and change the valvesprings.

Dutchesscamaro

iTrader: (1)

Nmbr1GMfan

If I was guaranteed that was the fix, I would change them in a second.
Did you change the springs on your GTO install?

Too many similar setups to mine with 6psi and 500+ rwhp and no spring change.

PLucas

iTrader: (1)

Do you notice the lack of power on the street? If not take it to another dyno or to the track and see what kind of power it is making.

JL ws-6

iTrader: (50)

how many miles are on your stock springs?

Dutchesscamaro

iTrader: (1)

6,000 k=miles on stock springs

Dutchesscamaro

iTrader: (1)

As for street driving... I feel that it follows the dyno curve.

Power comes on hard 2000 to 3000 then falls flat.