gear options

[wicked68]

I have a TKO600

At the MWMCC this weekend - I was able to run 124 on the straight after putting in my new 3.50 rear end. Finch beat me by 1 mph on the spectre top speed challenge. I was rev limiting in 4th gear.

I tried shifting to 5th once but almost immediately dropped 10 mph after the shift. I am pretty sure I have a .6 gear for 5th.

Obviously this is too tall. What would you guys do?

I have 575 rwhp - clearly enough to dominate the top speed contests - but my gears are not quite right.

Would you go to a .8 5th gear and have it still pull or would you go to a .9 4th gear and maybe a .8 5th as well?

I am at a 1.0 4th currently and pulls very well.

Thoughts????

[LSx_88_Ciera]

you can't get anything other than a 1:1 4th so your only option is a different 5th

[Kenova]

... or more gear in the rearend. Try 3.70/3.73s

Ken

[wmhjr]

... or more gear in the rearend. Try 3.70/3.73s

Ken

+1

[LSx_88_Ciera]

Going to 3.73 isn't enough final drive would only go from 2.24:1 to 2.39:1
If money is not an issue the better 5th is the best solution 1:1 to .64:1 is just too big of a jump.
If you don't want to spend the money for the better 5th trans your best choice is 4.56 rear IMHO. You may be thinking that is too much gear but in reality it isn't. On a road course you very rarely use 1st gear and with a 4.56 rear you are effectively splitting all of the gears vs a 3.5. In other words 2nd gear would feel like 1.5, 3rd - 2.5, etc.

[wicked68]

Going to 3.73 isn't enough final drive would only go from 2.24:1 to 2.39:1
If money is not an issue the better 5th is the best solution 1:1 to .64:1 is just too big of a jump.
If you don't want to spend the money for the better 5th trans your best choice is 4.56 rear IMHO. You may be thinking that is too much gear but in reality it isn't. On a road course you very rarely use 1st gear and with a 4.56 rear you are effectively splitting all of the gears vs a 3.5. In other words 2nd gear would feel like 1.5, 3rd - 2.5, etc.

money is not the issue.

so what gear do you think? .8 or .9 ?

[LSx_88_Ciera]

money is not the issue.

so what gear do you think? .8 or .9 ?

When it comes to a TKO 600 there are only 2 options

2.87, 1.89, 1.28, 1.0, .82
2.87, 1.89, 1.28, 1.0, .64

[wicked68]

When it comes to a TKO 600 there are only 2 options

2.87, 1.89, 1.28, 1.0, .82
2.87, 1.89, 1.28, 1.0, .64

got it. thanks - I guess I will try the .82 then.

I assume this one will still pull after 4th winds out?

[LSx_88_Ciera]

If it doesn't I would be amazed based on your stated RWHP.
Curious what is the car/motor?

[TnBlkC230WZ]

If money is no object, look at the T-56 Magnum. It has a .80 5th and .63 sixth. If it strickly a top speed car, look at the Richmand or GForce 5speeds. 4th can be setup as and overdrive with 5th 1:1 to truely custom taylor your gearing.

[Scott Parkhurst]

T56 w/ 3.89s will give you 130+ at 6,500 in fourth and 1,500 rpm in 6th on the fwy.

Otherwise, you could up the rpm potential of the engine in 4th (cam/valvetrain), and spray it to get the rpm up there in a hurry.

[wicked68]

T56 w/ 3.89s will give you 130+ at 6,500 in fourth and 1,500 rpm in 6th on the fwy.

Otherwise, you could up the rpm potential of the engine in 4th (cam/valvetrain), and spray it to get the rpm up there in a hurry.

its a pushrod motor with a hydraulic roller cam - I have it rev limited at 6k to keep it safe and it really quits making power anyway at about 6k-6200.

[Yelcamino]

I'll share my real world experience from the Maxton Mile...

I have 619hp at the flywheel. With a 3.25 rear gear, 26" tall rear tire, 1:1 fourth, 6800 rpm through the lights, my best top speed was 163.5 mph.

On one run I tried my .82 fifth gear and it slowed to 153 mph. Obviously the .82 and 3.25 combo didn't work. I recently installed a 3.70 rear so next time I go to Maxton I can find out if the .82 will pull better.

[Scott Parkhurst]

its a pushrod motor with a hydraulic roller cam - I have it rev limited at 6k to keep it safe and it really quits making power anyway at about 6k-6200.

Oh- okay. Easy! Go with solid roller lifters. Add a bit more cam and pull to 6500-6700.

[AMC Racer]

If money is no object, maybe a Rockland T56 Tranzilla or PPG/Keisler to get a close ratio 6 speed?

Tranzilla:
http://www.rsgear.com/products/tranzilla.asp

PPG/Keisler:
https://www.pro-touring.com/forum/sh...ad.php?t=63513

For ultimate flexibility, maybe a Jerico road race 5 speed - virtually unlimited gear selection.
http://www.jericoperformance.com/5speedroad.htm

The synchronized Tranzilla would be the most street friendly ... but all of these are very pricey options.

[avewhtboy]

You can get custom gear made for 5th, might check into that, we were running out of RPMS really early in 4th
on the back straight at road america so we had a custom 5th gear made just for that track. We were not making your kinda
horsepower so that could limit your choices, but it worked, we ran away from other cars on the straight.

[wicked68]

You can get custom gear made for 5th, might check into that, we were running out of RPMS really early in 4th
on the back straight at road america so we had a custom 5th gear made just for that track. We were not making your kinda
horsepower so that could limit your choices, but it worked, we ran away from other cars on the straight.

I am going with a .82 5th so I think I will be able to win the next top speed award - finch better watch out. I came in 2nd on that at 124 at mwmcc and finch beat me by 1 mph. I think this will fix that. I also removed my intercooler so I think I will pick up another 30 hp by eliminating the pressure drop. Its getting there.......

[LSx_88_Ciera]

I am going with a .82 5th so I think I will be able to win the next top speed award - finch better watch out. I came in 2nd on that at 124 at mwmcc and finch beat me by 1 mph. I think this will fix that. I also removed my intercooler so I think I will pick up another 30 hp by eliminating the pressure drop. Its getting there.......

I have to disagree on the increase in power from removing the IC unless you have a severe amount of drop. You have to realize that by cooling the air pressure will drop due to it increasing in density, still the same amount of air though unless there is a leak or reversion. Not to mention you will have to either increase the fuel octane or back off the timing.

How much pressure drop do you have?

[wicked68]

I have to disagree on the increase in power from removing the IC unless you have a severe amount of drop. You have to realize that by cooling the air pressure will drop due to it increasing in density, still the same amount of air though unless there is a leak or reversion. Not to mention you will have to either increase the fuel octane or back off the timing.

How much pressure drop do you have?

don't know yet. haven't run it.