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Moving the PowerBand Lower

Posted By: 6bblFLASH

Moving the PowerBand Lower - 10/07/20 11:06 AM

505" 440. 11.9 cr.
271@.050 roller 106 c/l @106. .609 lift
Std port heads.
Estimated powerband now 4 ,000 to 6,500-ish
Would like to launch lower with out laboring the engine.
Has plenty of SLR 15.56 now.
Would like to leave at 2,500 or 3 000 and let the torq do all the work instead of the clutch.
Currently takes more base to launch than hold 4th.
Don't need to go this fast anyway. Often 60ft.s with the back tires.
Smaller cam and less compression is not out of the question.
Advancing this cam would yield some improvement, but wouldn't think it would be enough.
Posted By: 80fbody

Re: Moving the PowerBand Lower - 10/07/20 12:02 PM

Stupid question probably. What happens if you just leave at 3,000? Damn thing has got a ton of torque and lot of gear anyways...
Posted By: 6bblFLASH

Re: Moving the PowerBand Lower - 10/07/20 12:22 PM

Would require added base pressure.
Which I would have to add anyway... but am concerned about lugging the engine and detonation.
I think I will have to lower the compression to launch that low safely.
Tried launching at 4,000 a few times.
Carried the front 80+ft.
Maybe pull some timing would be better.
Posted By: DoubleD

Re: Moving the PowerBand Lower - 10/07/20 01:40 PM

pulling some timing is the easiest thing to try - you can also go to a programable ignition and pull timing at launch then add it back in - or you know my favorite response - put a automatic in it
Posted By: Cab_Burge

Re: Moving the PowerBand Lower - 10/07/20 03:27 PM

If the ignition timing change doesn't work I would, and do, advance the cam from 3 to 6 degrees on the intake lobe center scope twocents
Look closely at the reaction and 60 ft. times when testing both scope
Posted By: metallicareload

Re: Moving the PowerBand Lower - 10/07/20 06:07 PM

You all are out of my league, please excuse my dumb comments but: what about moving the car to the power band with gearing? Though it looks like you'd be bouncing off the rev limiter on the top end, if you arent already? What launch RPM is safe?
Posted By: 6bblFLASH

Re: Moving the PowerBand Lower - 10/07/20 09:47 PM

Originally Posted by metallicareload
You all are out of my league, please excuse my dumb comments but: what about moving the car to the power band with gearing? Though it looks like you'd be bouncing off the rev limiter on the top end, if you arent already? What launch RPM is safe?


I normally launch at 5,000,,,,,,,shift at 6,500 and trap about 6,800.

It works pretty good, but is killing the clutch at this current style of run.
However it is a bracket killer.
At Keystone in 4 rds.

009,,
009,,
.030,,
.009 reaction times.
Ran .11 off my dial in the semis and lost by .004 due to the clutch going away.
🤬🤬🤬
Posted By: Grizzly

Re: Moving the PowerBand Lower - 10/08/20 12:05 AM

Is going to a 3.09 first gear ratio an option?

If so, it would drop a thousand rpm off your launch. Made a significant difference in my 4 speed. twocents
Posted By: 6bblFLASH

Re: Moving the PowerBand Lower - 10/08/20 01:50 PM

I have a 3.19 1st ratio now 4.88 rear gear.
Not sure I follow "thousand-rpm" with 3.09 ratio???🤔
Posted By: gregsdart

Re: Moving the PowerBand Lower - 10/08/20 02:06 PM

Originally Posted by 6bblFLASH
Would require added base pressure.
Which I would have to add anyway... but am concerned about lugging the engine and detonation.
I think I will have to lower the compression to launch that low safely.
Tried launching at 4,000 a few times.
Carried the front 80+ft.
Maybe pull some timing would be better.

Pulling timing on a timer would seem to be the easiest, and modifieable as well. Then you can retune as you like (cam advance etc) narrower rear tire a possibility?
Posted By: Grizzly

Re: Moving the PowerBand Lower - 10/08/20 02:17 PM

Originally Posted by 6bblFLASH
I have a 3.19 1st ratio now 4.88 rear gear.
Not sure I follow "thousand-rpm" with 3.09 ratio???🤔


Okay, got it, I thought you might have had the 2.47 first gear.
Posted By: 6bblFLASH

Re: Moving the PowerBand Lower - 10/08/20 02:44 PM

No worries.
I didn't think about posting all the ratios since it started as an engine question.
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