car has a th-400 freshly rebuilt and a 2300 stall tq converter.

 

Well, part of the problem is that the engine is lean throughout the entire RPM range. The WOT air ratio should be as close to the 13.2 to 13.5 range as you can get it. Did the dyno operator say anything about this?

BigBlockk

Later.....

 

Not bad for stock. I spent 4500 with a new GM Crate motor and hears what I got.



I was hoping for 325 RWHP. Remember HP costs money.

 

car isnt stock. it has headers and exaust back straight pips.

 

Your car being stock or not has nothing to do with what I said. The engine is running very lean at WOT. You need to correct this condition. A bonus is that you will find some horsepower when you get it fixed. The story does not end with you getting low power numbers on the dyno, it begins. In other words, this is when you start tuning.

BigBlockk

Later.....

 

not sure what you mean about the weight?
the curb weight of my 78 corvette is listed at 3572
the 1980 corvette is listed at 3495.

what i found on the LS1 trans am coupe is right around
3500 with the vert around 3600 due to hydraulics and
frame stiffening.

one of the biggest misconceptions is that C3s are light
because they are fiberglass.

 

HP = Torque x rpm/5250

The torque and hp curves will always cross at 5250.

 

I always get a chuckle out of these dyno test threads...

Marketing...


New cars today all just cram marketing down your throats


1. My wifes Saturn V6 supposedly has 210HP


2. A C6 Vette Z06 supposedly has 505HP


3. My 1980 Vette AT when I first got it supposedly had 230HP




In reality using a MUSTANG RW Dyno, this is what the real numbers looked like:

1. wifes saturn- 131hp

2. z06 (C6 vette)- stock Z06 were averaging 430-440hp (some where running much less but most were 430) manual trans too!

3. my 1980 vette- 181hp with mild cam, edelbrock intake & new 600 carb.



Guys... These numbers were all at the rear wheel. They were done at a very respected & noted race tuner TJ wong in Vancouver WA. witnessed by my own eye *****.
THAT IS AT THE WHEEL REAL/RAW number, not bench racing BS.


Wanna know more???

When I added 3" true dual exhaust my HP went from 181 to 185hp. that's 4hp...read that as FOUR. not huge.
so when guys say they put a free flow cat or just headers and a new carb then estimate that they now have 60 more HP, I laugh. Spedalen is right: HP cost Money

BUT... On the flip side, a brand new 2007 Pontiac GTO thing punched out a whopping 447 RWHP right after I came off the dyno!!! Talk about being embarrased!:o


point is, don't put too much stock in a dyno. They are great to "TUNE" the car with. A dyno tune is one of the best things to do to a car (imho).

 

It wouldn't be the first time an after market company stretched the truth regarding their products. I think all crate engine builders need to add the statement "Your results may vary" to the ads. A friend of mine runs a dyno, he says he gets a lot of ZZ4 equipped cars with the owner expecting their car is going to spin the dyno drum right out of the floor only to be disappointed by the end of the night.

 

Don't cry about it, open your wallet and fix the problem. Heads, cam, intake, and or boost. Step to it.

 

There was a C3 owner on the DC forum, who gained a dyno proven 80 hp when he upgraded his stock exhaust to a magnaflow exhaust. I can find the thread if there is a question. The reason being, the stock cats were sh*t, and many of them are clogged. So 60 more hp... I could believe it. And I'm not one to let people get away with ridiculous hp claims.

When I had the original L48 and I upgraded the exhuast, there was an huge difference in power. 6 years ago I raced my friends 95 GT mustang, he had headers and straight pipes. That car was supposed to be good for 220hp stock if I remember correctly. Anyways, my lil L48 walked that 5.0, with my single exhaust stock manifolds and all of the emissions crap still in place, and I had a passenger (he did not), AND I had an auto trans at the time.

That's interesting that the new Z puts down around 430, I just put down 432 at the wheels with a bunch of stuff wrong. Now I kinda want to run with a new Z and see how I do. Any takers?

 

My relatively stock 2000 Z28 dynoed at 318 rwhp. Your buddy's 298 rwhp doesn't sound way out of line. Remember, the only difference between a Z28 and an SS is ram air and that doesn't come into play on a chassis dyno. They're both LS1s.

 

OK. Aside from your wife's Saturn, your other rwhp numbers are right in the ball park. Lets assume a 15% drive train loss for your Z06. 430 rwhp/.85 = 505 fwhp. If we assume 20% los for your 80 Vette (older technology drive train) then 181 rwhp/.80 = 226 fwhp. The Saturn was just not hacking it. 131 rwhp/.85 = 154 fwhp.