94-6spd

I just had my car dynoed last week and the numbers weren't as expected. I know everyone says that when they dyno their car but this car runs 11.20's @ 119 mph. The best was 11.19 @ 119 with a 1.53 60' time. I expected 435 hp or so.

AlkyIROC

375 hp on a dynojet dyno

What's your race weight? Saying it runs 11.2 doesn't mean much if we don't know the weight. Weight of the car, fuel, driver etc going down the track.

What was the density altitude when you ran that or at least what were the weather conditions and altitude of the track?

The engine's hp level changes as the DA goes up and down. The dyno HP is, or at least should be, corrected for altitude and weather conditions. That means if you took the car to Florida or Denver and put it on a dyno, the results should be the same but the car will run a lot slower in Denver because it's making less hp at altitude.

94-6spd

I don't know the race weight but I have pulled out the ac and smog equipment and put on a glass hood. The cage and subframe connectors probably canceled that out. I'm guessing 3400 lbs. The altitude of the track was probably really close to sea level also. It was Memphis motorsports park. I plan to weigh the car this week. The weird thing is that my buddies modded Z06 is putting down 452 hp and is slower. His car is 3100 lbs. We have been going to the 1/8th mile tracks lately and his best is 7.52 @ 98 mph. I have been going 7 teens @ 98 and 99 mph.

AlkyIROC

Memphis Motorsports Park is listed as 540 feet altitude. That still doesn't mean you wern't racing on a day where the DA was at 2000 feet or maybe a very good day were the DA was below sea level which is possible at low elevation tracks.

MPH is your indication of HP. ET depends on too many variables to easily calculate it from HP. Spin off the line and ET slows but MPH stays the same. Pick up a tail wind like I did in the first round today and the car picks up ET unexpectedly.

A dyno is only good for tuning. What happens on the strip is what the car will really do. We don't race dynos and race weight means including the driver since the car doesn't race itself.

Tom 400 CFI

What he said.

Also, IMO, your peak and upper RPM power could be hurting some from your 650 CFM carb. I think you could be running those great times due to total car set up (that goes for a lot!), and because of a big, broad torque curve from a 400 good heads and good 650 CFM carb. The set up probably puts a bunch of torque down over a wide range, which gets you great 1/4mile performance, but the small carb could be clipping a significant peak off you hp graph.

-Tom

85z28guy

I hate how hung up people get on dynos! Not ragging on you, but you have a nicely setup car to hit those numbers with the hp period (I mean that as a compliment ) .People love to throw parts at a car, then ask why it ran a 14 sec 1/4 mile. Obviously you have done the right thing, and looked at all the variables, not just hp.

94-6spd

Thanks 85Z28guy for the compliments. I actually did go to the dyno for tuning. I was hoping that tuning would gain me 10 or 15 hp at the wheels. I was going to be in Bowling Green to race that night anyway so I decided to get my car tuned there. The guy that was there to tune my car was from Holley. Excellent tuner from what I understand. Anyway, the air and fuel was right on and he said that we shouldn't touch the carb. We did check timing and at 3000 rpm and it was about 32 degrees total. So we bumped it up to 36 total and it only gave me 2 hp more. I had a 750 speed demon on before and I didn't think performance was right on so I called Barry Grant and they recommended a Mighty Demon 650 for cams with over 240 degrees of duration @ .050. I just want to say how satisfied I am with the Demon Carb. I put this on last year and adjusted the idle mixture screws with a vacuum guage. I haven't touched it again. Not even the floats. Haven't had the bowls off of it yet. All the Holleys that I've loved in the past can't compare to this Demon. The Demons actually are flowed differently so the 650 is actually what my 406 needs. No way would a Holley 650 work as well on a 406.

I was just expecting more on the dyno because the car has ran so good. Not complaining for how the car runs at all because I built it to just get into the 11's and 10's on spray. When I went to the track and it went low 11's I was tickled to death to say the least. I was so excited that I called my friends on my cell phone saying "Your'e not gonna believe this"! We were all shocked. Just an engine I built in my garage. Not a high buck crate engine. When I got home from the track I started reading up on some dyno numbers of cars running 11.20's. Most were around 420 to 430. I even went to smokemup.com and did the figures. That also said that 3400 lbs. would take 430 hp.