Hello,
I have been struggling with an issue all year and need some advice.

I am running a 235 inch Super Comp Dragster

Over the winter I upgraded the heads on my 582 in my dragster and upgraded my PG case to an SFI case and straight cut 1.80 gears. I made 985 HP on the dyno, which is over 100 HP more than my old setup made.

Last year I ran 8.90 at 163. I could run my stop at 4600 rpm and it would cleanly come up to 6000 when the stop came off.

This year, if the stop RPM is under 5000, the car will only go to 5400 before slowly climbing RPM. Because of this, the car is really slow after the 330.

If I launch the car hard, it seems to run just fine. On a pass with the stop RPM at 5100, I ran an 8.20 at 169 at 4000 DA.

Here is what we have done so far:
Different Type of Throttle Stop
Different (Known Good) Carb
Different MSD 7-al2 and Pro Power Coil
Different Cap and Rotor
Verified Timing at 36
checked throttle linkage and disabled SLE
2 Different Converters with 6300 and 6700 stall (also sent to mfg and verified to be good)
Different Brand of Spark Plugs
Transmission checked multiple times for no parts breakage or issues

I do have logs from the datamaxx I can show if that will help.

If anyone has any other ideas to try or has had this before it would be greatly appreciated. Thanks.

What size is the carb? I have seen this happen with the carb too large for the application. Verify there is nothing floating around in the bowls. What is your fuel pressure with engine off, and at idle?

Have you tried more or less timing?

I have tried a 1050 and 1150 that both have been run on similar throttle stop engines.

I am running 9 lbs of fuel pressure with the engine off and at idle, about 7 going down the track.

I am gonna guess that is the flash stall of your converter? Throttle stops like really loose converters.
Also, check the throttle stop solenoid. If it is air, spray some WD-40 in it and make sure it operates cleanly. If it is electric, make sure you have a heavy, like a 10-12 gauge wire, going to it.

mark

What kind of throttle stop is it? In-line air throttle stops are the most responsive. I have seen electric solenoids hang up and slowly release the flaps back to wide open position. If its not an air throttle stop then its something easy to try

If it is not the throttle stop itself (or electric wiring of the throttle stop) then it is either: air, fuel, or converter most likely

What is your rear gear ratio and what size tires are you running?

What head were you running and what head did you switch to?

I am running air stops. have used an inline and an under carb stop with the same results. We have adjusted the flow control to slow down and speed up the release with no improvement

I am running 4.30 gears with Hoosier 33 x 16 tires.

I went from Brodix 2xtra heads to AFR 385 heads.

Has anyone ever had an issue after swapping the case that the converter charge pressure was too high? we measured the pressure at the cooler lines and it was about 60 lbs at idle but went up to 140 lbs when I was against the brake at 4500.

Check at the servo in low, high and transbrake.

Sounds like the convertor to me, even though they have been checked. I would borrow another one and see what happens.

I know the pressure was at 210 at the servo against the transbrake and in low gear. I think it was the same in high but I would have to look at my notes.

Cam not degreeded correctly?
Almost sounds like timing way behind.
BB just thinking out loud

Run the car wide open. See what it runs. No stop. Take the plate off if it’s a plate stop. That engine at that hp should run pretty fast. 4000’ is about the worst air I ever see around here and my car with a 565 is going to go 7.60 or better at 175-176 at Numidia which is possible to see 4000’. My engine was never on a dyno but there’s no way it makes more than that 985 number and it has run 8.90’s at 175-176 with a plate stop in good air. I usually am in the 172-174 range. Your heads are pretty big but couldn’t be killing the run that bad. I always run my cars wide open to make sure it runs what it should and runs well and consistent before I t-stop it....

quote:

Originally posted by Camaro80z:
I am running 9 lbs of fuel pressure with the engine off and at idle, about 7 going down the track.

Well that's a red flag.

I did try to run it wide open at the test before the divisional at BIR. I had the timer for the shift out too far(2.5 seconds) and it hit the rev limiter and had to lift for a little over a second. I had a 1.13 60 foot, a 5.35 660 and a 8.20 . The mph was down from lifting.

A 1.13 60ft on a 582 inch, close to a 1000 hp engine in a dragster wide open throttle? 5.35 660?

Something doesn't sound right. I think you need to look further into the severe lack of power for a average 582 in a dragster.

The first thing you can do is, take a leak down test as well as a cranking compression test.

quote:

If I launch the car hard, it seems to run just fine.

Apparently it does not run fine.

This message has been edited. Last edited by: Strange Magic,

Your 60ft wide open should be a tenth quicker than it is. You have an issue other than the one you are seeing on the stop.

quote:

Originally posted by BLIND MULE 2217:
Your 60ft wide open should be a tenth quicker than it is. You have an issue other than the one you are seeing on the stop.

Especially if you have a 4:30 gear and 33" tall tires

I agree with Strange. My 60’ with injection on my 565 was 1.07-1.08 and with a gas carb a little slower. A 582 would be at least as fast unless you had a really soft converter or timing launch retard.

!

This message has been edited. Last edited by: 67TSCHEVY2,

With a 4.10 gear I shifted on time at 2 seconds or less. As low as 1.6 trying to slow down and that was well below 7000. 2 seconds was about 7100-7200 IIRC....2.5 with a 4.30 gear would be up a lot higher in RPM.

quote:
Originally posted by Camaro80z:
I am running 9 lbs of fuel pressure with the engine off and at idle, about 7 going down the track.

Well that's a red flag
X2