Dyno...Whats up????? Rwhp???

[Coupe50h]

Originally posted by 420nitro
If itsany help my first combo was a GT-40 package from Anderson Motorsports. GT-40 heads, Gt-40intake. E-303, Mac 1 5/8 full length hearders, 2 1/2 off-road h-pipe, Flow-masters, 4.10 gears, and a Tremic Transmission 3550. The car made 268 rwhp at the same dyno shop. Car went as follows on average.
60 foot 1.71-----1.76
1/8 mile 8.0's-----88
1/4 mile 12.50's---107
Now I dont know if maybe the shop I went to was calibrated differntly or what, but all the race cars that had race prepped transmissions that made anywhere close to 500 rwhp were all solid 9 sec cars that weighed close to 3000 pounds.

May i ask what size injector you ran on that combo?
with that 60' thats about where my car should be.
with a t-5, your dyno would have been a little better, i think the tremecs eat a little hp, probaly not much, what was the weight?
my car is about 3120 with me in it, im hoping to see 280rwhp, but even if it's under that, i know the stock 300rwhp ls1's have all kinds of gap to fill at the track as soon as i leave line the SS's are tough to hold off on the topend though.

like mentioned above, i just want to dyno for shift points, and see what the wideband says, so i can adjust fuel pressure, i wont brag on anything, and say im faster than so in so, because i dyno xx, it comes down to who can ride that sucker to the 1320 ft the quickest imo.
good day

[420nitro]

Originally posted by Coupe50h
May i ask what size injector you ran on that combo?
with that 60' thats about where my car should be.
with a t-5, your dyno would have been a little better, i think the tremecs eat a little hp, probaly not much, what was the weight?
my car is about 3120 with me in it, im hoping to see 280rwhp, but even if it's under that, i know the stock 300rwhp ls1's have all kinds of gap to fill at the track as soon as i leave line the SS's are tough to hold off on the topend though.

like mentioned above, i just want to dyno for shift points, and see what the wideband says, so i can adjust fuel pressure, i wont brag on anything, and say im faster than so in so, because i dyno xx, it comes down to who can ride that sucker to the 1320 ft the quickest imo.
good day

At that time I was running 24 pound injectors with 36 pounds of fuel pressure at idle with the vacuum port disconnected. TPS sensor was dail in at .998 volt. Car indle at 850 rpms. 17 degrees base timing. (spout connector disconnected.) Car also had 4.10 gears.

[420nitro]

Sorry, I forgot the car weighed at approx. 3,400 pounds at that time.

[BilLster]

i saw a new type of dyno that bolted to the rear studs ( you removed the rear wheels) and its supose to be more accurate.

And as someone said elevation can play havioc with hp numbers and if your car doesnt hook it doesnt matter how much rwhp you have but dyno's are great tuning tools and can help find problems on a new engine before you blow it up,

I always tell people no matter how much hp you have it's the first guy through the traps that wins.

[andy669]

Originally posted by Coupe50h
with a t-5, your dyno would have been a little better, i think the tremecs eat a little hp, probaly not much

About 4-5 percent more. With a T-5 thats broken in we will see about 12-13%, whereas a Tremec is about 17-18.

Andy

[302 LX Eric]

Originally posted by andy669
About 4-5 percent more. With a T-5 thats broken in we will see about 12-13%, whereas a Tremec is about 17-18.

Andy

Agggghhhhh!!! I knew it! I should've kept my T5

E

[420nitro]

Originally posted by andy669
You need a load bearing chassis dyno to accurately read horsepwer and torque on a car with a stall convertor. Like you mentioned, with an inertia dyno they will show low horsepower numbers, but they will also show high torque numbers. If the inertia dyno is operated correctly they can still be used as a tuning tool, but comparing horsepower numbers is silly.

On a manual transmission car, its a different story. The Dynojet 248 I have access to is very repeatable. I have been on 3 different 248's and the corrected numbers are usually within 5-7 horsepower of each other. To me, thats close enough for me to quote what my car makes and feel confident that I'm not mis-representing.

Andy

Hey andy I checked into this and found that I was using and still using a dyno which is called (mustang dynamometer). Which is quite different from a Dynojet 248! This Mustang dyno can simulate elapsed time tests (1/4 mile pass)! You can use the transbrake and launch the car off of 6000 rpms and simulate a full pass!!! This dyno is not an inertia dyno. You can make a pass and hold the car at a predetermined rpm and check your wide band o2 and make the adjustment right there while under load!!! The only thing is that it gives a much lower h.p #.The more h.p you make, the more it will vary from a dyno jet (it"s on a percentage).
Example: Fact
My friends down south dynoed a car with 650 rear wheel horse power and could barely keep it tied down. (auto-with a loose converter) Went to the track and gave the car 5psi more boost and blew off a low 8 second pass.! Now on a dyno-jet it would of probably made some where in the 900-1000 hp+ but it would of taken a lot longer to dail in.

On motor my car went 12.0 @ 112 with 310 rwhp.
With 8 psi it went 10.9 @ 128 with 430 rwhp.

The car weighed about 3200 with me in it. These are Dynojet numbers with a 3500 stall convertered C4. A stick might have shown 450 RWHP.

It goes to show you don'y have to make big numbers to run decently fast. A nitrous car might run even faster with an equal peak hp number considering nitrous makes a TON of torque down low compared to a blower.