gear ratios

KY JELLY wrote:

Lem Evans wrote:What's that gotta do with finish line rpm?

the engine is the boss on whether the rpm is right or not at a 1000' it seems happy with 4:86. It takes 1.83 seconds from 330- 660 and 1.61 seconds from 660-1000.

Seems you are the boss of/if the conv locks up good in high gear.....again......my bad.

no I am not trying to be sarcastic but I would think less strain on the converter would lock it up quicker just my opinion

It's ......being the conv. needs to lock up better i.m.o.

My last words be them right or wrong.
#6 water line kind of a deal.

Have you worked up the slip % on the converter?

What formula do you use Jon one that averages the entire run or actual engine/ driveshat rpm to feet per second ?



I had a long talk with ptc and there is a set tire diameter for what a 4.86 gear is "really" supposed to based off . They seem to think stay with the 4.86 and that there is not any converter problem I think what we came up with was around 6-8% slippage.

Lem I am not afraid to say you told me so , #6 water line or fuel pump ?

I appreciate it Travis and might take you up on it , but I am probabaly gonna try the 5:13

Most just look at the trap rpm, I know when I'm geared for the 1/4 the slippage at the 1/4 mile trap is in the 4% range. The 1/8th trap % is much higher. It depends a lot on the stator design, degree of the "windows" etc...............how aggressive the converter is.

A guy could test a pile of converter and gear combo's to get it perfect, I rekon "perfect" depends on what your after........................

call Lenny

I am not opposed to calling anyone and I might just do it

You have math and you have the real world facts (time slip) as far as car performance is concerned.

To me and the real world passes I have personally seen from my car and my competitors ,the only #'s that do not match within reason are my 60 times. My 60 times are way quicker than they should be and that's comparing to other cars and you can even try the famous wallace caculator . http://www.wallaceracing.com/etcalc.php

The car has 330' 3.22-3.25 , et 5.03 -5.10 mph from 135 -138 mph .

I have got several 60 times at 1.07, 1.08, and one 1.05. I don't think anyone could argue that it takes well over 1030 hp to produce 1.0 60' times at 2400lbs and My engine is not making that much power by a long shot so either the converter is multiplying torque from m-5 fumes or something is going on.

here is a qualifying sheet from one of our races

Duck is running a 706 cid , the rest of the 140 mph cars are blown and the rest except mine are spraying nos

Can you get rid of 200 lbs somewhere?

Time to trade your knife for a gun IMO, and I dont think gears, converters, M5, S10 pumps, green oil, highspeeds, nano-domes etc is gonna be enough to get it done.

now Fabio we all know a little squirt of giggle gas would do it .

then what are you waiting for?

Lem Evans wrote: A small block gear in that package? I'd guess I'm missing something.

Hell Lem, we run 3.50's with our small block turd (low 1.20's sixty foot on a 29.5x10.5 tire). I pretty much live in the small block world and I don't know anyone running the gear ratios I read on this site, big blocks or small blocks. and I am talking 4.80-5.30 3000lb cars. some of them even NA.

If all gear ratios are based on about a 26-27" OD tire, then it makes sense that a car with a taller OD tire could need/use a steeper gear ratio than what is thought of as the "norm" and still be in the correct RPM range for a given engine combo.

we run a 5.00 in the brown turd, but its only a 28" tire lol

whatbumper wrote:

Lem Evans wrote: A small block gear in that package? I'd guess I'm missing something.

Hell Lem, we run 3.50's with our small block turd (low 1.20's sixty foot on a 29.5x10.5 tire). I pretty much live in the small block world and I don't know anyone running the gear ratios I read on this site, big blocks or small blocks. and I am talking 4.80-5.30 3000lb cars. some of them even NA.

A small tire with a heavy car and lots of power will not tolerate the torque load a big tire and a light car will. An efficient launch will get up on the tire quick and most times slip the tire just a bit.

You are just gaining most of your acceleration on the other half of the track because your tires would literally bounce off the track if you threw all of the torque multiplication to them off the line whether it be through gearing or high stall speed.

anyone interested this is what Marty Chance had to say

Marty Chance
Post subject: Re: Marty can I get your opinion
PostPosted: Wed Jan 19, 2011 8:14 am
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Joined: Fri Sep 19, 2008 6:34 am
Posts: 139
Location: Cheney, KS
sound like the combo is pretty close. do you know what the rpm drop is on the shift? The 5.13 gear may help it accelerate better especially in high gear where the spragless will hold back the engine rpm rate and may help the launch be more consistant by allowing you to leave from a lower rpm chip

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Again you'll just have to try it, honestly I dont think the 5.14 will help much if any. And the spragless does explain some of the et and mph loss on down track.


You can play the numbers all you want, but the timeslip will be the final say if it works or not.

What et loss are you speaking of ? The mph and et are very close to what they should be.

Does it not seem strange to you that an alcohol engine of this size would like the rpm this one does ? Who knows why, it might be Lem's cam , Charlie and Laws port job , the tfs intake manifold , but it does not drop hp very quickly at all above 7000rpm it keeps on accelerating.

You are right the et slip tells the tail and every move I have made with this engine it says "I want to be turned in my upper rpm range"

The converter and gear has got to coincide with where the engine accelerates the quickest, if the chassis and tires will handle it , it will run quicker. It does not matter what you think or I think.

my old motor liked rpm, so I see no reason this one wont...again trial and error lol.

A spragless converter will eat up some et and mph over a sprag type, more of a topend deal.

KY JELLY wrote:What et loss are you speaking of ? The mph and et are very close to what they should be.

Does it not seem strange to you that an alcohol engine of this size would like the rpm this one does ? Who knows why, it might be Lem's cam , Charlie and Laws port job , the tfs intake manifold , but it does not drop hp very quickly at all above 7000rpm it keeps on accelerating.

You are right the et slip tells the tail and every move I have made with this engine it says "I want to be turned in my upper rpm range"

The converter and gear has got to coincide with where the engine accelerates the quickest, if the chassis and tires will handle it , it will run quicker. It does not matter what you think or I think.

so.....when are the new gears gona be in?