Any final opinions?
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Any final opinions?
Going to order rebuilt diff today or tomorrow....Planning on ordering 3.90's to go with my 383 and Keisler TKO-500. My goal is streetable but the ability to light the tires on those occasions that call for it.
Any last thoughts or opinions before I do?
Any last thoughts or opinions before I do?
Instructor
Joined: Sep 2006
Posts: 192
Likes: 0
From: Fort Lauderdale FL
Have a cold brew
Enjoy, you'll be happy with the results, only concern may be the 3.90 rear, this may be too much for the TKO's first gear, or rather 1st gear may be all but useless. I have a 3.54 rear and 1st gear is very short, with a 3.90 you may only be in 1st as long as it takes you to shift to 2nd.
Melting Slicks
Joined: May 2005
Posts: 2,826
Likes: 3
From: Tennessee
3.90's will render your 1st gear useless. I wouldn't go more than 3.55 with your 1st gear ratio of 3.27:1.
I think I've mentioned this before but my personal car has a TKO-500 and I'm running 3.73's. I have to shift within 30 feet(give or take) of taking off. For me, this suits my driving style but to most, it would drive them nuts. Yes, I can roast my tires at will and in the RARE occasion that I actually hook up off of the line, it will throw you back in the seat hard enough to make John Force smile.
I would really consider a 3.55 if I were you.
Richard
Instructor
Joined: Mar 2006
Posts: 127
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From: Miami FL
wow so much hating on 3.90's which imo is the perfect ratio!! go for it dont worry about first gear they are exagerating, it's still usefull for whats its meant to do, get you moving!
3.90's all the way!!!!!!!
3.90's all the way!!!!!!!
Melting Slicks
Joined: May 2005
Posts: 2,826
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From: Tennessee
Richard
Tech Support
Instructor
Joined: Sep 2006
Posts: 192
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From: Fort Lauderdale FL
That may be fine for some but even from the performance perspective having to shift so quickly actually costs you time which will drop your performance, (time wasted shifting 1st to 2nd after 30 feet or so)
As mentioned a 3.55 or less would be a better option all around. Even with a 3.55 your overall ratio in fifth will be a 2.41 with the 0.68 fifth, or a 3.05 if you have the 0.86 optional fifth gear. I defer to Richard on the details.
Cheers
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Le Mans Master
Joined: Jul 2005
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From: Austin Texas
You will not be happy with 3.70 or 3.9's. Kind of defeating the features of the overdrive trans. You won't even make a left or right turn without having to shift in the middle, not to mention any gains in 5th gear fuel savings. 3.36 is perfect, IMHO!
Drifting
Joined: Sep 2006
Posts: 1,259
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From: MS
Just for comparison sake, a TKO-500 with a 3.90 rear will have the same starting ratio as an M22 with a 5.80 rear axle and I don't think anybody would recommend that combo for the street. The 3.90s would be a terrible choice with a 3.27 first gear. You would have a 12.75 overall first gear which is almost 18-wheeler like low. About 10 to 1 overall low gear is what you want and even the 3.36 puts you at 10.98 to 1 so I would say 3.36 is about your only choice.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
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From: Austin Texas
Just for comparison sake, a TKO-500 with a 3.90 rear will have the same starting ratio as an M22 with a 5.80 rear axle and I don't think anybody would recommend that combo for the street. The 3.90s would be a terrible choice with a 3.27 first gear. You would have a 12.75 overall first gear which is almost 18-wheeler like low. About 10 to 1 overall low gear is what you want and even the 3.36 puts you at 10.98 to 1 so I would say 3.36 is about your only choice.
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Just for comparison sake, a TKO-500 with a 3.90 rear will have the same starting ratio as an M22 with a 5.80 rear axle and I don't think anybody would recommend that combo for the street. The 3.90s would be a terrible choice with a 3.27 first gear. You would have a 12.75 overall first gear which is almost 18-wheeler like low. About 10 to 1 overall low gear is what you want and even the 3.36 puts you at 10.98 to 1 so I would say 3.36 is about your only choice.
This one of those areas where the cars I learned to work on we never really went through these types of decisions.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
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From: Austin Texas
Basically, if your in a gear for less than a second at full throttle, you don't get any work done by the engine's torque. The magical number "10" for 1st gear x rear axle ratio has been used as long as I have been fooling with these cars. Go above 10+ or 11 and you need really sticky tires and a 8,000 rpm engine to utilize these ratios. I am coming from a practical viewpoint. I have seen so many people change gears higher (numerical) and see little or no inprovement in E/T. G/L
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Basically, if your in a gear for less than a second at full throttle, you don't get any work done by the engine's torque. The magical number "10" for 1st gear x rear axle ratio has been used as long as I have been fooling with these cars. Go above 10+ or 11 and you need really sticky tires and a 8,000 rpm engine to utilize these ratios. I am coming from a practical viewpoint. I have seen so many people change gears higher (numerical) and see little or no inprovement in E/T. G/L
Thanks for your patience...
Le Mans Master
Joined: Jul 2005
Posts: 5,752
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From: Austin Texas
No problem.....Rear ratio changes have a point of diminishing returns. I have a Richmond 5 speed trans. in my '68, with 3.08 rear. Is 10.08 first gear. With the 383...pulls like hell in first gear.
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
I have 3.70s in my TKO 500 and don't mind it a bit. It is a little short in first but it rockets off the line. If I had to do it over I would probably go 3.55 but no lower. The 3.90s are going to be even shorter and unless you have a high rpm motor it might be a little to much. I like the 3.55 or 3.70 gear in a performance motor. 1st and 2nd gear can be smokin at will with my motor but I don't think a different gear would make a difference. Plenty of torque available.
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Alright....So better understanding everything, I put together a chart
And here is my dyno chart (at the flywheel) from when Jasoer built the engine
The more conservative route would say stay lower (i.e. taller), the more aggressive route would say go higher (i.e. shorter). And after going through all of the posts again and again, I beginning to think Richard (who I thought left Keisler but still has the logo as his avatar) is right. Not that this is a surprise to anyone who has dealt with him. The 3.55 will give me just enough crazy but not over the top....kinda like my wife <looks over shoulder>
Shane
And here is my dyno chart (at the flywheel) from when Jasoer built the engine
The more conservative route would say stay lower (i.e. taller), the more aggressive route would say go higher (i.e. shorter). And after going through all of the posts again and again, I beginning to think Richard (who I thought left Keisler but still has the logo as his avatar) is right. Not that this is a surprise to anyone who has dealt with him. The 3.55 will give me just enough crazy but not over the top....kinda like my wife <looks over shoulder>
Shane
Veteran
Joined: Oct 2005
Posts: 1,284
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From: Nashville, TN
Instructor
Joined: Sep 2006
Posts: 192
Likes: 0
From: Fort Lauderdale FL
Alright....So better understanding everything, I put together a chart
And here is my dyno chart (at the flywheel) from when Jasoer built the engine
The more conservative route would say stay lower (i.e. taller), the more aggressive route would say go higher (i.e. shorter). And after going through all of the posts again and again, I beginning to think Richard (who I thought left Keisler but still has the logo as his avatar) is right. Not that this is a surprise to anyone who has dealt with him. The 3.55 will give me just enough crazy but not over the top....kinda like my wife <looks over shoulder>
Shane
And here is my dyno chart (at the flywheel) from when Jasoer built the engine
The more conservative route would say stay lower (i.e. taller), the more aggressive route would say go higher (i.e. shorter). And after going through all of the posts again and again, I beginning to think Richard (who I thought left Keisler but still has the logo as his avatar) is right. Not that this is a surprise to anyone who has dealt with him. The 3.55 will give me just enough crazy but not over the top....kinda like my wife <looks over shoulder>
Shane
BTW did Richard leave Keisler?