Ianz06

How is this done?

The car has 437 rwhp and the rpm limit tables have been adjusted.

The stock table in 5th gear was set to 9000 rpm and we verified this.

Since the mods, each limit was adjusted to 6900 rpm in each gear.

The car before the mods on the highway would run up to an indicated 172/173 mph on the HUD, which equated to 175
mph on a gps.

The car with the new mods and on a dyno (no wind resistance) runs up to an indicated 172/3 really fast then crawls to 177/178 mph then stops.

There must be a 'soft' limiter somewhere that is interfering.

Anyone know how to remove it or bypass it?

MA_sadsaudasjk

I used LS1 edit on my 2003 Z06 and the factory setting for the speed limit comes set at 255. I don't think you are hitting a limiter, just running out of power.

John

StevieZ

iTrader: (3)

With 437 RWHP he is NOT running out of power. With that HP he should be good for 185 mph easy.

Cal

iTrader: (1)

Were the injectors upgraded to support the 437 RWHP?

trackbird

iTrader: (4)

The mention of a "soft limiter" makes me question a couple things:

1.Enough fuel pump?
2.Clogged fuel filter or air filter
3.running out of injector

I suspect that during an extended dyno pull you should produce enough load to show any weaknesses in the fuel system.

Also, on a dyno, wind resistance is minimal and I would expect that you should be able to run the car out of gear in 6th (at 200+ mph), not that this has much bearing in the real world.

C4VetteLS1

i have a dynojet chassis dyno...and for one when you do dyno pulls you are not pushing very much mass at all compared to driving. The rotational mass of the wheels is constant, so your not pushing the full weight of your car. Plus you are not pushing ANY wind resistance which is a huge difference.

I can take a stock honda to 150+ mph with 125 horsepower because of this if i want.

You should easily be able to take 6th gear to redline on the dyno...only thing i can think of is a fuel problem....it takes a LOT of fuel to push a car to those rpms in 6th gear

Ianz06

I'm not aware of any injector upgrades but will ask the tuner.

The air filter is new and the car runs fine elsewhere so i doubt it could be the fuel filter but who knows, i will check anyway.

Based on how it pulls to the 173/4 mph it feels like a software based limiter, i need to try to capture what the fuel and timing tables are doing and save the data.

Thanks for the feedback.

trackbird

iTrader: (4)

I was simply speaking of surface frictional drag on the drums. I believe the rollers on a dynojet are 5700 lbs each (11,400 lbs total).

Good luck!

66ImpalaLT1

Are you in 5th gear?

Ianz06

On the dyno 5th gear was used.

On the street 5th and 6 th gear were used and the results were all the same 173/4 mph on the hud

C4VetteLS1

Yes the dyno wheels are heavy but your pushing them on ball bearings..i can get on the dyno and run with my feet and make it spin..

trackbird

iTrader: (4)

You are correct, they are heavy but easy to roll (that was actually the point that I didn't make very well) and the air drag on the drums is nearly nothing, so it is easy to reach high speeds on a dyno....Guess I should have been more specific.....