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Guess E.T change going from 4.88 to 4.30 gears
#270820
03/29/09 08:18 PM
03/29/09 08:18 PM
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Joined: Jul 2008
Posts: 51
Cumberland, MD
Supersonic
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Cumberland, MD
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440 with 915 heads, shifting at 6 and going through at 7200 running a 10.38 @ 127 with 4.88's. I figure with the 4.30's it will go through at about 6400, what should the ET be at? I think i was well passed the peak power level of the 915's at 7200.
Last edited by Supersonic; 03/29/09 08:22 PM.
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: Supersonic]
#270821
03/29/09 08:41 PM
03/29/09 08:41 PM
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Joined: Apr 2005
Posts: 1,880
USA
Ron Silva
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USA
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It will cut your ET by .2 to .25 as long as your converter is not loose as a goose. I am going to say you were hooking before based on your time vs speed. But if it was not hooking before it will pick up a little more and be more consistent.
You did not say how tall your tire was and please tell your 60 ft.
SRT DEMON ONE SEAT
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: Ron Silva]
#270822
03/29/09 08:55 PM
03/29/09 08:55 PM
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Joined: Aug 2006
Posts: 2,505
God's Country Maryland
GODSCOUNTRY340
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God's Country Maryland
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Quote:
It will cut your ET by .2 to .25 as long as your converter is not loose as a goose. I am going to say you were hooking before based on your time vs speed. But if it was not hooking before it will pick up a little more and be more consistent.
You did not say how tall your tire was and please tell your 60 ft.
My 60 was 1.44, and the converter stalls at around 4300. It hooks pretty good about 70% of the time. Tire is 32x14 goodyears
Last edited by GODSCOUNTRY340; 03/29/09 08:56 PM.
I love the smell of Deer guts in the morning, it smells like... VICTORY!
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: RemCharger]
#270824
03/30/09 12:39 PM
03/30/09 12:39 PM
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Joined: Jan 2003
Posts: 9,999
Frostbitefalls MN (Rocky&Bullw...
gregsdart
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master
Joined: Jan 2003
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Frostbitefalls MN (Rocky&Bullw...
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You may pick up some, but that converter is still way tight at 4300. I have seen 440 ironhead combos pick up ET by running converters considered way too loose. My buddy Joe put one in that flashed 6000 at the line, he shifted at 6200, and went quicker by over .05. He didn't like it, tightened it up, and it went slower. Not much, but there was a loss.
My bet is to run a converter that will leave the line at just over 5000, and shift at 6000 if that is what works. I only have about an800 rpm window in my combo.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: B1MAXX]
#270828
03/30/09 02:56 PM
03/30/09 02:56 PM
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Joined: Jul 2008
Posts: 51
Cumberland, MD
Supersonic
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Cumberland, MD
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Quote:
I tried this, going from 4.56 to 4.30 and lost almost .3 went from 10.0's to high 10.20's. All combo are different but I wouldn't do it. Unless your trying to slow the car down. Its better to be gearbound IMO.
What heads did you have on your car?
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: Supersonic]
#270831
03/30/09 05:14 PM
03/30/09 05:14 PM
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Joined: May 2005
Posts: 1,986
Apollo, PA.
B1MAXX
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Apollo, PA.
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Quote:
Quote:
I tried this, going from 4.56 to 4.30 and lost almost .3 went from 10.0's to high 10.20's. All combo are different but I wouldn't do it. Unless your trying to slow the car down. Its better to be gearbound IMO.
What heads did you have on your car?
B1BS
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: B1MAXX]
#270832
03/30/09 05:33 PM
03/30/09 05:33 PM
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Joined: Jul 2008
Posts: 51
Cumberland, MD
Supersonic
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Cumberland, MD
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Quote:
Quote:
Quote:
I tried this, going from 4.56 to 4.30 and lost almost .3 went from 10.0's to high 10.20's. All combo are different but I wouldn't do it. Unless your trying to slow the car down. Its better to be gearbound IMO.
What heads did you have on your car?
B1BS
I plan on getting a set of those or the indy ez-1's later this year. They say those b1 heads really like high rpms.
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: B1MAXX]
#270834
03/30/09 09:14 PM
03/30/09 09:14 PM
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Joined: Feb 2006
Posts: 698
Alberta Canada
Edge
mopar
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mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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I would not suggest going all the way to 4.30 gears. 4.56 may be a better compromise. I would tend to agree that the car is likely laying over trying to turn it above 7000 RPM with 915 heads.
76 Duster
work in progress
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: Edge]
#270835
03/30/09 09:57 PM
03/30/09 09:57 PM
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Anonymous
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Anonymous
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I bet it won't hurt it.......I'd be surprised to see more than a tenth ET loss if it does....... 
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Re: Guess E.T change going from 4.88 to 4.30 gears
#270836
03/31/09 02:16 PM
03/31/09 02:16 PM
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Joined: Jul 2008
Posts: 51
Cumberland, MD
Supersonic
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Cumberland, MD
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Quote:
I bet it won't hurt it.......I'd be surprised to see more than a tenth ET loss if it does.......
If it runs the same et or faster at lower rpms i will be happy, if it slows down any at all i'll be putting the 4.88's back in
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: B1MAXX]
#270838
03/31/09 10:36 PM
03/31/09 10:36 PM
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Joined: Jan 2003
Posts: 19,363
Las Vegas
Al_Alguire
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I Live Here
Joined: Jan 2003
Posts: 19,363
Las Vegas
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Well good luck with it. I am going the other way from .30 to 4.88 and hoping to pick up a tenth or so.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Guess E.T change going from 4.88 to 4.30 gears
[Re: Al_Alguire]
#270839
03/31/09 10:41 PM
03/31/09 10:41 PM
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Joined: Feb 2006
Posts: 698
Alberta Canada
Edge
mopar
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mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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As an alternative if you have the room and need tires you could go to a taller tire ? Instead of changing gears I am moving from a 31.8 to a 33 tall tire (approx 5 MPH higher at same RPM)
Good luck with your change
76 Duster
work in progress
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