Re: How much ET expect to lose from 3.91 to 3.23?
[Re: OA5599]
#951139
03/15/11 01:38 PM
03/15/11 01:38 PM
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Joined: Dec 2003
Posts: 2,586 Illinois, Indiana, Louisiana
ProStDodge
master
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master
Joined: Dec 2003
Posts: 2,586
Illinois, Indiana, Louisiana
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Quote:
it depends a lot on how optimised your converter is for your combination. in a previous life i experimented with gear ratios, and found that the converter is way more important than getting the theoretical optimum gear ratio.
Switching from 3.91 to 3.23 will make the converter work harder, and if it is too tight, it could prevent the motor from getting up into the power band quickly. So how much time you lose will depend a lot on the converter.
Another thing to think about, the switch to the 3:23 gear will place a higher torque load on the gear set, increasing the chances of breaking the bearing caps. (think of it like a 10-speed bike - attempting to start out fast in a low gear just gets your feet moving fast. Start in a high gear and you can feel the pedal arms flex, the frame creak and groan.)
With 550hp you might want to start thinking about a Dana. Yes, I know this has been hashed out over and over on this board, with lots of poeple saying they never have problems with a 8-3/4. But most of those folks either have light cars, less than 500hp (despite what they think they have), or never run sticky tires.
Back in the 80's I never thought I would need a Dana either, that was before I knew what actual horsepower and traction were. After several hogs heads, twisted axles, and bent housings, it became evident switching to a Dana was a bargain. Oh yeah, that was in a 3800# '71 SuperBee running 11.70's (slicks and 4-speed).
Scott
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: ademon]
#951142
03/15/11 06:40 PM
03/15/11 06:40 PM
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Joined: Jul 2006
Posts: 4,319 Puyallup, WA
StealthWedge67
master
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master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Unless they're outrageously efficient, track officials won't do (or know) anything @ a test-n-tune, certainly not until they actually see you going faster than you're legal. Of course, it will come to light if you dial in at under 11.50 (If they're paying attention).
I'm not trying to advocate being illegal, I just think you oughta go see what it does before you assume its gonna be under the 11.50 mark. You may (likely) get there eventually, but that's pretty fast, and it will likely take some tuning and adjustments before you get there. I don't think you should just assume the cars going to hit its potential right out of the shoot, and why slow it down before you even know if you have to or not.
Last edited by GEnsrud; 03/15/11 07:23 PM.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: maximum entropy]
#951143
03/15/11 07:35 PM
03/15/11 07:35 PM
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Joined: Feb 2005
Posts: 4,333 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,333
Prospect, PA
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Quote:
it depends a lot on how optimised your converter is for your combination. in a previous life i experimented with gear ratios, and found that the converter is way more important than getting the theoretical optimum gear ratio.
Tire makes a difference too. If you are traction limited, the gear change will have less impact.
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: BloFish]
#951149
03/16/11 01:30 PM
03/16/11 01:30 PM
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Joined: Jan 2003
Posts: 24,562 Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Just run the 3.91, and see what it does. Then if you need to switch, then go for it
what he said. Usually you'll get at least one warning before you are booted. As mentioned 75% of the time nobody will even care. But to answer your question if the car is set up for 3.91's then you'll drop .3-.5 seconds off your et as the car will not be into the powerband quick enough.
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: Mr.Yuck]
#951150
03/16/11 01:44 PM
03/16/11 01:44 PM
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Joined: Mar 2009
Posts: 1,058 bigfork mn
dragram440
super stock
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super stock
Joined: Mar 2009
Posts: 1,058
bigfork mn
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I would run it with the 3.91's also you wont get booted on your first pass with the new setup.if If it runs to fast then slow it down. They wont let anything slide at the track I race at but you wont get kicked out on your first pass. They will tell you to slow it down befor they kick you out.
67' charger 499 RB
10.57 at 127
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: OA5599]
#951154
03/17/11 12:31 PM
03/17/11 12:31 PM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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if you are too fast, it's much easier and cheaper to lift at 1000' than it is to swap pumpkins....
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: How much ET expect to lose from 3.91 to 3.23?
[Re: patrick]
#951155
03/17/11 01:20 PM
03/17/11 01:20 PM
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Joined: Jan 2003
Posts: 24,562 Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
if you are too fast, it's much easier and cheaper to lift at 1000' than it is to swap pumpkins....
or just short shift it. Easier on parts and you'll be more consistant if you plan on bracket racing it.
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