robyyzpapa

I made a pull on the dyno the other day and couldn't believe I made 400 rwhp and 402 pound feet of torque. Not bad for a stock motor with a 6 lb blower.

wrd1972

Nice,
Do you have a graph you can show us, I want to see the torque curve.

robyyzpapa

Thanks, to be honest, that was a one time pull with those numbers. With the car warm and the blower hot, I was getting between 385-388 rwhp. Then I let the car sit for a good hour to cool right down. Then I tried it again, and came up with 400. Check the link for the graph. Notice how power drops right off after 5000 rpm. Weak valve springs perhaps?


http://i237.photobucket.com/albums/f...pa/Picture.jpg

speed_demon24

Is that the same setup you ran 12.9@112 with? And your a/f is on the lean side for a f/i setup.

robyyzpapa

Yeah, my best time is with this current setup. I know it could be better, but I have a hard time launching the car with my radials. I have a spec clutch in it and find it hard to modulate it of the line. I either spin the tires or bog the motor. Plus the car is full weight and I am over 250 pounds myself. I want to put some stickier tires on, but I'm afraid the rear end will let go and I'm not ready right now to replace it.

As for the air/fuel ratio, I'm going to get my buddy to try some more tuning, but I may need new injectors, right now I have 30 lb accels.

JP95ZM6

I wouldn't call that a dropoff after 5000 - looks like it keeps pulling to 5700+ pretty solidly. Withour smoothing, a lot of dyno runs are not nice smooth lines, they are rather wavy. Based on the sharp power transitions (bumps ) at the top end, I don't think there is heavy smoothing applied to your curves. Nice curves.

Road load or inertia dyno?

robyyzpapa

Not sure, the dyno is a dynojet. Why do you think my torque drops off so much after 5000 rpms?

JP95ZM6

Don't know about the torque decline, but from the few examples I've been shown, valve float is a very abrupt drop, not a gradual decline. My graph suddenly drops like 40 HP within a couple hundred RPM at the top end, for example. I have NOT confirmed it's float (don't want to dis Bret's valvetrain without cause!), but the dyno operator said that is just what it would look like. Ignition could do that, too. And probably a lot of other issues....

Gradual decline I would think is breathing, fuel starving, or something else progressively running out of capacity, but not hitting a valvetrain resonance. I'm not well informed enough to say what's most likely, though.

CANTONRACER

HP is derived from RPM and torque...as your rpm's increse your torque declines because your HP is increasing.

Simple formula....(tq X rpm) / 5252

What I would be wondering about is why your car is running like it is making 350 rwhp?

Live in the mountains...bad day of weather?

As you can see in my dyno graph...torque drops fast past 5000 also.



Also notice the car starting to blip at 6100 rpm and just die at 6500 rpm...I believe that was caused by my shattered opti-spark that I recently replaced...yet have not run yet.

robyyzpapa

Well like mentioned above, my 60 foots are really crappy. That best e.t. was done with a 2.1 short. I figure, if I can get the car down to a reasonable 1.8 short, I would be somewhere in the mid 12's and mph would pick up a bit as well.

Also, the car is full weight, (even with the spare tire and jack in the car) and I weight about 250, so there is quite a bit of mass to get down the track.

I want the car to stay a pure street car with no suspension mods or weight savings (like taking out the a/c system).

GTOnTA

There is nothing wrong with your torque dropping off after 5000 rpm. Torque will always be lower than HP above 5252 rpm, and the reverse is true below 5252 rpm - where torque will always be higher than hp.

Also, torque drops off above 5000 rpm more drastically with a small (stock/factory) cam than it would with a longer duration cam, all else being equal.

slomarao

if you want a pure street car y wouldnt you want to upgrade the suspension?

robyyzpapa

What I meant by that was I don't want to do a drag suspension set up, where the car looses it's cornering capability. I can't really lower the car either, cause my custom y-pipe hangs a little low and don't want to scrape it.

By the way I just cleaned my car and put it under a car cover for a long winters nap. It's going to be a long 6 months!

RealQuick

You hit the nail on the head. Back when I had 368rwhp/336rwtq I ran 12.5 @ 114 w/ 2.0 60', so you got some bugs to work out if you have 400rwtq and 400rwhp. My car was full weight (minus the spare and jack) and had a 3.73 gear.

RealQuick

BTw, nice numbers on the dyno though!