60ft issues

[CamCam]

Well i don't think rick waters lied about the figures, we know there is a gremlin in the chassis. But do appreciate the advice. We will keep searching.

Originally Posted by Jeff Lee

If the dyno is correct, 690 HP would be around 135 MPH. That's 5-6 more than you are showing. Fixing the clutch or traction issues isn't going to bring the MPH up much, if any. So the bottom line is, something is amiss in the HP department of the vehicle. That could is typically ignition or fuel issues. As an example, you will feed plenty of fuel to the engine while it is on the dyno because there's nothing to cause problems. But if the fuel system is not able to keep up with the engine while under a heavier load, or the system can't push enough fuel through the system, then your HP will be cut drastically. And in your case, I see 75+ missing. That's significant.
My suggestion is to find the missing HP which will cure the low MPH issue. Then you can work on the rest of the car.

[Pvt Parts]

What's the transmission gearing? Where are you shifting it and what's the rpm at the finish line??? I'm having a problem seeing how a 3,500 lbs car with a small block making 690 needs a 4.88 gear.

[Jeff Lee]

Originally Posted by CamCam

Well i don't think rick waters lied about the figures, we know there is a gremlin in the chassis. But do appreciate the advice. We will keep searching.

If you re-read my post, I didn't say the dyno HP is a lie. I'm saying the HP got lost on the way to the track. Don't take it personal, it happens a lot. Fuel, ignition, gearing, hood clearance, etc., there are many ways to loose power.

[Mike Taylor 3601]

How much tq.@ what rpm does tq.&hp peak@.
I don't know anything about your combo, but I would guess launch is too low,clutch probaly too tight, 4.88 gear too high. it's choked down.
Mike Taylor 3601

[Pvt Parts]

Originally Posted by mike taylor 3601

how much tq.@ what rpm does tq.&hp peak@.
I don't know anything about your combo, but i would guess launch is too low,clutch probaly too tight, 4.88 gear too high. It's choked down.
Mike taylor 3601

x2

[Ed Wright]

Yeah, there are more problems than 60'.

[Pvt Parts]

Originally Posted by Mike Taylor 3601

How much tq.@ what rpm does tq.&hp peak@.
I don't know anything about your combo, but I would guess launch is too low,clutch probaly too tight, 4.88 gear too high. it's choked down.
Mike Taylor 3601

I made 758 with a 353 and a single 4, shifted at 9200 and crossed at 9300. Same rpm with more power out of a 402 sbc. He has to be at 8600 or more to make decent power and that's gonna take a 5.86 or more with a 3.11 to 3.25 transmission to run decent et's at 3500 lbs depending on the tire.

[CamCam]

Ok the tranny ratio's are 1st 306 2nd 191 3rd 133 4th 1.1. Engine peak is 690.1 @ 7200rpm peak torque 555 ft pounds at 5300rpm. Shift's are made at 7500 and go the traps at 7000.

Originally Posted by Pvt Parts

I made 758 with a 353 and a single 4, shifted at 9200 and crossed at 9300. Same rpm with more power out of a 402 sbc. He has to be at 8600 or more to make decent power and that's gonna take a 5.86 or more with a 3.11 to 3.25 transmission to run decent et's at 3500 lbs depending on the tire.

[Mike Taylor 3601]

Here's what I would try, I would take 2 step chip out use high side limiter I'll guess you have 8k already in high side, Every car I have ever had the higher rpm I leave @ the faster they go,but of course I'm talking about using common sense though,your're engine is peaking @ 7200 I would GUESS 8- 8.5K are sensible rpm.Anyway whatever chip is highside limiter I would be comfortable leave line there, if engine won't stand what high side is then chip is too high.
Then I would come out of low about 7K or just high enough not to bog,2-3 about 7.5-7.7K, 3-4 about 7.5-8 K.
When launch is raised one of two things will probaly happen if car is wheel standing now it may calm that some because where you are launching it could be dead hooking,or it may blow tires off if it does,back clutch off,btw keep backing off till it slips in high gear,you'll know because frontend will start bouncing up and down like you're whomping the gas.
It could be hard to get this car working with that gear 4.88 w 3.06 is pretty tall low(14.93)
as example you probaly run 5.38 which would lower 1st to 16.46.which would help,easier on clutch & trans,but more pressure on axles.
Or you may go fastest it's been.
I would start air gap @.050 if you have'nt checked set this .050 is baseline wider hits harder closer hits softer,if shifting w clutch .050 is probaly as tight as you want to go.
This is what I would try might help might hurt but there's only one way to find out.
You could probaly gear for 7800-8000 @trap also(5.38)
Mike Taylor 3601