Re: Suggested redline for mild 512
[Re: radar]
#2674807
07/06/19 12:24 PM
07/06/19 12:24 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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Go back to the chassis dyno and make a few pulls, adding a few hundred rpm to the top of each pull......... up to the point where you encounter valve float, or reach an rpm limit you’re comfortable with. I think you’ll reach the valve float stage well before 6500. Whatever rpm it occurs at....... the “redline” should be a few hundred rpm lower than that point. the torque is over 525 and slowly tapers down to more like 450 at 5500rpm but the rear wheel hp was still climbing there, hitting 362 at 5500. Look your sheets over more carefully. The hp is just a calculation of tq and rpm. If you have 450tq@5500 rpm...... that’s 472hp. Conversely....... 362hp@5500 is 344ft/lbs. HP is always higher than TQ at rpms above 5252, TQ is always higher than HP at rpms below 5252.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Suggested redline for mild 512
[Re: radar]
#2674815
07/06/19 12:33 PM
07/06/19 12:33 PM
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Joined: Feb 2003
Posts: 1,099 Massillon, Ohio
cudatom
super stock
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super stock
Joined: Feb 2003
Posts: 1,099
Massillon, Ohio
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I have a similar set up. Best et has been shifting at 5500. 7.02 in the 1/8 and 11.08 in the 1/4. Thats at around 4100 lbs. Runs out of steam above that. No reason to beat the snot out. Of it if it performs better shifting lower.
Ok
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Re: Suggested redline for mild 512
[Re: AndyF]
#2674855
07/06/19 02:10 PM
07/06/19 02:10 PM
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Joined: Dec 2012
Posts: 1,823 Wind Gap,Pa.
Sammy
top fuel
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top fuel
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Wind Gap,Pa.
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That combo is probably all done by 6000 rpm. You can push it past that if you want, but I doubt the car will go any faster. Try it and see what happens. My guess is that you'll want to shift it at 5500 to 5800 with a rev limiter of 6100 or 6200. BINGO I agree
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Re: Suggested redline for mild 512
[Re: radar]
#2674897
07/06/19 04:43 PM
07/06/19 04:43 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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You’d have to know exactly what the speed was at the point the motor was at 5252rpm.
That chart only goes to 75mph........ no way the wheels only going 75mph at 5500rpm in high gear.
If you’re not in high gear, then I’m sure the added gear reduction is throwing a wrench in the calculations.
Oh........ and don’t even try and correlate the wheel hp number to the crank hp. An excersize in futility.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Suggested redline for mild 512
[Re: J_BODY]
#2674915
07/06/19 05:36 PM
07/06/19 05:36 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
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I Live Here
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So. Burlington, Vt.
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Here’s something I just thought of......
How does that Mustang dyno determine tq/hp? Is there a load cell or is it an inertia dyno.
With a load cell...... I guess I don’t really know what they use for a formula to come up with “wheel hp” based on the “wheel tq”.
On an engine dyno with a load cell, you get a reading off the load cell, and apply the math to arrive at the hp figure. Without knowing the rpm for the reading/measurement taken by the load cell...... there’s not really a way to know what the “hp” is.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Suggested redline for mild 512
[Re: fast68plymouth]
#2674939
07/06/19 06:23 PM
07/06/19 06:23 PM
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Joined: Dec 2005
Posts: 1,495 Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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I never do dyno pulls in second gear it screws the results. Go back and do it in high gear and keep going up on rpm until it noises over
JAKES AUTOMOTIVE
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Re: Suggested redline for mild 512
[Re: JAKE68]
#2674941
07/06/19 06:32 PM
07/06/19 06:32 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
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Found this in the Mustang dyno operators manual: When engine RPM is not available, there is no way to report an engine crankshaft relative torque value. If it’s not engine crankshaft relative, then it won’t necessarily cross at 5252, since it’s also not rpm related.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Suggested redline for mild 512
[Re: radar]
#2675005
07/06/19 08:59 PM
07/06/19 08:59 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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Also- we tuned in 2nd so it wouldn’t kick down. I’m not sure how we could avoid that? Just disconnect the kickdown lever from the throttle linkage for the pulls. For what you were doing, the tests were fine...... as long as you used the same procedure for all. Then you’re just looking for the numbers to be better than they were...... and then you know you’re making progress.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Suggested redline for mild 512
[Re: fast68plymouth]
#2675123
07/07/19 10:34 AM
07/07/19 10:34 AM
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Joined: Jul 2007
Posts: 1,682 Philadelphia
radar
OP
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OP
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Joined: Jul 2007
Posts: 1,682
Philadelphia
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Also- we tuned in 2nd so it wouldn’t kick down. I’m not sure how we could avoid that? Just disconnect the kickdown lever from the throttle linkage for the pulls. For what you were doing, the tests were fine...... as long as you used the same procedure for all. Then you’re just looking for the numbers to be better than they were...... and then you know you’re making progress. I was super happy with the power improvements down in street driving range. I always get nervous about beating on my equipment loading it up with resistance on the dyno- the chassis and driveline will never see that much stress on the street because the tires unload first. Since my slip yoke let go later that day and took out my transmission doing a holeshot I’m guessing we put plenty of beating on her while strapped down. It’s probably a good thing we didn’t do any more testing on the rollers but I am a little regretful we didn’t keep spinning it till it nosed over. Now the truck has been back in action a couple weeks with 1350 yokes and a fresh 727. It probably won’t go back on the dyno unless I do bigger headers or change something major but if/when that happens I’d like to be able to run it in high gear. So pin the throttle pressure lever it all the way back? I’d hate to burn up my clutches with low atf pressure. Unfortunately I want results from 2500 or 3000 up- starting at 4500 sounds more like race engine stuff. Thanks for the lively discussion fellas. I’m always learning
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