Drag Racing Tech - Lets talk about Nitrous 6 speed cars and Gear and tire combos.

As of right now I am planning to run 4.11 gears in my 9" with a 28" tall tire and a 150 shot on a cam only LS1.

I always thought it was best to run as low a gear as possible and put as big of a tire as you could on it to increase the roll out.

I would like to run a 4.56 gear with a 29" tall tire if it will make me faster but also I dont want to spin the motor 7500 rpms to make the 1/4 in 4th gear.

This car will see more "mexico" races than anything else so I need it to work on the street.

The tires will be Bias Ply tires of course. Thinkin hoosiers on a pro star, 11.5" wide and the height will be determined by the gear im running.

What gear/ tire size would you guys run and WHY?

WHEELSPEED accelerates the car, not engine rpm. More rear gear, gives you engine rpm and you need a good bit more of it, to increase wheelspeed

3:73-3:90 gear with a 28 inch tall tire......nitrous makes torque so let that pull you through instead of running a taller gear and a taller tire to spin the motor to the moon :)

then again i may be talking out of my ass

PM JL-ws6, master on this subject in all ways.

not to mention with 4.30 gears and a 28" tall tire i think you will be good to 124 mph at 6,000 rpm, you should go a bit faster than that, a 4.56 and 29" will likely be worse, and i know you don't want to spin the motor higher than that.

WHEELSPEED accelerates the car, not engine rpm. More rear gear, gives you engine rpm and you need a good bit more of it, to increase wheelspeed

3:73-3:90 gear with a 28 inch tall tire......nitrous makes torque so let that pull you through instead of running a taller gear and a taller tire to spin the motor to the moon :)

then again i may be talking out of my ass

No you're dead on.

It's like this, what would you use to get a rusty bolt off that is going to be stubborn as hell?

A short ass wrench or a long one? Same thing with longer gears and nitrous and boost.

No your are dead on.

It's like this, what would you use to get a rusty bolt off that is going to be stubborn as hell?

A short ass wrench or a long one? Same thing with longer gears and nitrous and boost.



yes it is

4.56 is a bit muchfor a 6 speed, I don't think you're gonna like that too much, especially with nitrous. I agree, go with a 3.73. I'm not sure if I remember right but I think I remember someone saying running a 4.56 on 28" tire with a 6 speed will mean finishing the 1/4 in 5th? Someone please correct me if I'm wrong though. That would be a nightmare... especially if you sprayed though 5th... kaboom.

if your tuneup is "spot on" for the nitrous, going through the 1/4 in 4th (1:1) and you spray 5th yes it will most likely spell disater.....you can spray 5th with enough timing pulled

4.56 is a bit muchfor a 6 speed, I don't think you're gonna like that too much, especially with nitrous. I agree, go with a 3.73. I'm not sure if I remember right but I think I remember someone saying running a 4.56 on 28" tire with a 6 speed will mean finishing the 1/4 in 5th? Someone please correct me if I'm wrong though. That would be a nightmare... especially if you sprayed though 5th... kaboom.

i have 4.56 gears with a 28" tire & spin it up to 7200rpm in 4th gear & make the 1/4 mile with a few feet to spare......

no nitrous tho......NA

just so you can compare the tire gear selection to nitrous.

4.56 would be fine for an na car, however nitrous creats so much torque that it would be unmanagable power and violent.

i have 4.56 gears with a 28" tire & spin it up to 7200rpm in 4th gear & make the 1/4 mile with a few feet to spare......

no nitrous tho......NA

just so you can compare the tire gear selection to nitrous.

Alright thanks, I couldn't remember if that was correct or not. Has a lot to do with cam selection as well. What cam are you running?

Ok Branden, u win. 3.73 and 28's it is lol.

just listen to your boy

I went 130mph
G5x2 4.30 gear 28in slick
150shot
Cam only

you would likely go faster if you dropped gear on the gas

3.73, 6 speed car, 28 tires, cam only with a 150 shot... Full weight? Yeah your car will be slow. That is not a good combination. Drop the clutch at 6K and you'll have so much initial wheel speed it will blow the tires off. If it hooks (and you don't break something) it will bog the motor right down, you don't have enough power.

Fast 6 speed guys will throw the max amount of gear at it they can. Figure what mph you'll trap at and put the most gear possible in it. 4:30-4:56 is what you'll need.

if your tuneup is "spot on" for the nitrous, going through the 1/4 in 4th (1:1) and you spray 5th yes it will most likely spell disater.....you can spray 5th with enough timing pulled

This must be a budy of yours.... Keep him as a budy but do not listen to his advise. He's way wrong on his gearing philosophy and to tell you it's ok to spray in 5th is just stupid. There are plenty of fast 6 speed guys to get proven advise from.

This must be a budy of yours.... Keep him as a budy but do not listen to his advise. He's way wrong on his gearing philosophy and to tell you it's ok to spray in 5th is just stupid. There are plenty of fast 6 speed guys to get proven advise from.



hmmmm you need to re-read my post and do a little more research, would i spray 5th gear no, is it ok with enough timing pulled YES people do it quite often at the texas mile, and i think you need to understand how nitrous work before you go shooting off about gearing.......in a 3,100 pound car with a cam and 150 shot+4.56 gears that will be unusable......so nitrous guru tell me why that would work.:guns:

oh I'm not here to get into a pissing match with someone that obviously doesn't know WTF there talking about.

If the OP wants to PM me and give me more information on his setup i'll be more than happy to give him some information based on lots of experiences with getting the most out of a 6 speed setup. Just don't want the poor fella spending money on a setup some yahoo gave him that will wreck his shit and slow him down.

trust me im not intending on getting into a pissing match, as far as not knowing what im talking about, well how fast have you gone? Ive been in the 8's for the most part and tuned all my own stuff to get there have you? Im just interested in understanding your philosophy on why you need that much gearing with nitrous, like i stated this does not need to turn into a pissing match, just a friendly debate if you will.

http://www.f-body.org/gears/ Not rocket science people.

http://www.f-body.org/gears/ Not rocket science people.

:D

3.73's are too little with a 28" unless your spraying way more than this guy, and I mean a lot like 400+.

4.56's are too much for a nitrous combo like this and 4.30's are pushing it a little bit.

If you want a good balance with room to spare for mpg's and more nitrous later on go 3.89's.

If you want max potential on 200-250 shot go 4.11's.

My earlier post was directed to using a 4.30 or 4.56 gear even with that much nitrous. Not only will it blow the tires off the line and be a dog out the hole with as much as it would take to make it manageable but it would be turning more rpm's than he is going to want to turn most likely with the set-up he is talking about.

my vote would go to 3.89/3.90 gear and a 28" tire with your setup. No sense in spinning to the moon with a stock bottom end/heads, the power just wont be there in that upper rpm band.

the op and I have discussed this and i said a 3.90 would be the middle ground for street/ strip, but we settled on 4.10's

With 28in tires..I have 4:10s..wish I could do 4:30s but I have a 3 series carrier... :/ Im right at 6000-6200 going through the traps.

Didn't read all the other post but i can give you my personal expereince. I have gone 10.06 with a cam only stock ls6 intake mani and pacesetters w/150 shot mph was 136. I use 4.30's cross the line around 7k as far as I am concenred the 4.30 gear is the absolute perfect gear for your set up. @70mph I am cruising around 2100-2200 rpms. With more power you might want to go with 4.10's but if you are sticking with a cam only set up with spray for a while go 4.30's. I consitently cut 1.40's on spray and have a textralia twin disk, and am on 28x10.50 slicks.

Didn't read all the other post but i can give you my personal expereince. I have gone 10.06 with a cam only stock ls6 intake mani and pacesetters w/150 shot mph was 136. I use 4.30's cross the line around 7k as far as I am concenred the 4.30 gear is the absolute perfect gear for your set up. @70mph I am cruising around 2100-2200 rpms. With more power you might want to go with 4.10's but if you are sticking with a cam only set up with spray for a while go 4.30's. I consitently cut 1.40's on spray and have a textralia twin disk, and am on 28x10.50 slicks.

While your times are good, I just don't see the point in stressing a stock bottom end without even rod bolts by revving a motor with a LS6 intake, stock heads, and 1 3/4 pace setter's to 7000rpm.

Now if it had a Fast 92 on it at least, a set of ported 243's or aftermarket heads and a bigger set of headers in a more max output type set-up on the stock bottom end then it'd b worth wringing it to 7k to get the power.

Take my set-up for example since we are comparing. I have 4.11's with a TH400, but I have a ported Fast 92 which takes it out to 96 a 96mm throttle body, and 1 7/8" ARH headers with 5" extensions with v-bands at the track, but I am planning on trying a longer set of extensions with bullet's or one chamber's instead of my vibrant turbo mufflers and I turn it 7000-7200 for it's sweet spot.

It's been 10.29 on motor with a worse 660' time than my personal 660' best which is 6.38@105 vs. the 6.49@104 on the 10.29 run. Granted you have a 6 speed.

comparing an auto to clutch car is apples to oranges. You have to have wheel speed/spin coming out of the hole other wise you bog. To much wheel speed and you go no where(or atleast not very fast). 4.10's would be a good gear still just not optimal for what the engine is wanting.
I am leaving at 6k or above on the 150 jets, and basically on my limiter NA which is @ 7200rpm's any lower and it would bog. Ultimatley just depends on what the OP wants. If you dont mind slipping the clutch you can get away with 3.90's or 4.10's it will just ruin clutches much quicker, and not be as consistent. I can pull up to the line put the rpms where I need and basically side stepp the clutch and consistently have 1.40's-1.45's.

As for what the engine wants. I have tried shifting at many different rpms and my fastest et's have all come from when I shift @ 7k

The most important lesson of all (be prepared to rebuild the t56 lol) I bent my mainshaft very badly last outing at the track.

http://www.youtube.com/watch?v=1pPuSzaURfo&list=UU1APIxPyMdZ7gaT6c40y8Kg&index=21&feature=plcp

How much does your car weigh ren?

Op what cam are you running, this year I will run a ms4,150 shot 4.30 gear.

402 ci w/200 shot 4:10s 28" slick 3,850 lbs. cross the traps around 6,500 rpms. click sig pic for video.

How much does your car weigh ren?

I honestly dont know I would guess around 32-3300 with me in it. It dynoed 401 NA and I never had it on the dyno with the nitrous.

402 ci w/200 shot 4:10s 28" slick 3,850 lbs. cross the traps around 6,500 rpms. click sig pic for video.

According to the gear calculator with 0 tire growth 6500 rpm with 28" tall tires and 4.11s = 132 mph. 6300 = 128 mph

According to the gear calculator with 0 tire growth 6500 rpm with 28" tall tires and 4.11s = 132 mph. 6300 = 128 mph

Interesting.

comparing an auto to clutch car is apples to oranges. You have to have wheel speed/spin coming out of the hole other wise you bog. To much wheel speed and you go no where(or atleast not very fast). 4.10's would be a good gear still just not optimal for what the engine is wanting.
I am leaving at 6k or above on the 150 jets, and basically on my limiter NA which is @ 7200rpm's any lower and it would bog. Ultimatley just depends on what the OP wants. If you dont mind slipping the clutch you can get away with 3.90's or 4.10's it will just ruin clutches much quicker, and not be as consistent. I can pull up to the line put the rpms where I need and basically side stepp the clutch and consistently have 1.40's-1.45's.

As for what the engine wants. I have tried shifting at many different rpms and my fastest et's have all come from when I shift @ 7k

The most important lesson of all (be prepared to rebuild the t56 lol) I bent my mainshaft very badly last outing at the track.

http://www.youtube.com/watch?v=1pPuSzaURfo&list=UU1APIxPyMdZ7gaT6c40y8Kg&index=21&feature=plcp

Very true, 6spd's need that wheelspeed out of the hole so they don't dead hook. Dead hook and your going on the bumper or breaking shit. Neither is fun, good pictures yes, fun....no.

So your spraying 150, on 28's and with 4.30's are already spinning 7 grand? What are you shifting at rpm wise?

I dunno what the OP wants to shift at, but your's will give him a good example of what his would most likely turn with a 150 shot and the 4.30's.

Your car runs good. Pill that bitch up some more!

Edit added: LOL I see that's an Arkansas tag now and not SC like I thought.

4.30 with 28" tire will do exactly what you want if you are going with a slick the tire will grow and hold your rpms down. Its not rocket surgery.

oh I'm not here to get into a pissing match with someone that obviously doesn't know WTF there talking about.

If the OP wants to PM me and give me more information on his setup i'll be more than happy to give him some information based on lots of experiences with getting the most out of a 6 speed setup. Just don't want the poor fella spending money on a setup some yahoo gave him that will wreck his shit and slow him down.

I can tell you that with 138 mph and 10.10 et your combo is not optimized completely. If it was then you could run that et with about 5-6 mph less trap speed at least. OP you would be alot better off to go with 3.89/3.90 and 28 in tire and run 200+ shot and keep rpm lower than 4.30/ 150 shot and spinning it to 7000 through the traps. It will stay together longer if the tuneup is there.

4.30 with 28" tire will do exactly what you want if you are going with a slick the tire will grow and hold your rpms down. Its not rocket surgery.

That's something new, Rocket Surgery....:devil:

haha!

Very true, 6spd's need that wheelspeed out of the hole so they don't dead hook. Dead hook and your going on the bumper or breaking shit. Neither is fun, good pictures yes, fun....no.

So your spraying 150, on 28's and with 4.30's are already spinning 7 grand? What are you shifting at rpm wise?

I dunno what the OP wants to shift at, but your's will give him a good example of what his would most likely turn with a 150 shot and the 4.30's.

Your car runs good. Pill that bitch up some more!

Edit added: LOL I see that's an Arkansas tag now and not SC like I thought.

I shift at 7k NA and around 6700 on n2o there is more et with the 150 shot but I don't have the coin to drop on a nice adjustable clutch.

I can tell you that with 138 mph and 10.10 et your combo is not optimized completely. If it was then you could run that et with about 5-6 mph less trap speed at least. OP you would be alot better off to go with 3.89/3.90 and 28 in tire and run 200+ shot and keep rpm lower than 4.30/ 150 shot and spinning it to 7000 through the traps. It will stay together longer if the tuneup is there.

so pilling it up more and a lower gear are a better solution? sounds like alot more cylinder pressure on the poor stock pistons :confused:

so pilling it up more and a lower gear are a better solution? sounds like alot more cylinder pressure on the poor stock pistons :confused:

I have seen more damage to LS1 from bad nitrous tunes and broken rod bolts/ rods from too much rpm than pistons from cylinder pressure... LS1 will take much more than 150 safely if the tuneup is right and rpms are kept reasonable. Are you saying it is safer to spray 150 and spin stock bottom end LS1 to 7000+ rpm than to spray 200 and spin it to say 6500 -6600 rpm? In case you haven't heard nitrous makes alot of torque and you don't need alot of gear or spin on to the moon to run good et's. Next time you dyno yours see where it makes peak power and torque on the dyno.

It wont go back to the dyno, but regardless of what the dyno shows I know from past experiences and trial and error where my car likes to be shifted to provided its best et. I also know it will be harder to get the car off the line with that gear and a normal clutch. Also I am not suggesting any way will last longer than the other once you start spraying nitrous on stock pistons it is probably smart to accept that your engine is living on borrowed time. And thanks for enlightening me that nitrous makes alot of torque. Also I guess you consider shifting at 66~6700 rpm on n2o spining it to the moon???

One thing you need to remember ren87 is that you have ARP rod bolts and not stock ones so you have a little measure of safety at 7000 rpms over a completely stock bottom end. Also with your T-rex cam yours would be a little pain in the ass to drive around on motor. T-rex loves nitrous though. You goal is also to get a cetain timeslip (9 sec)on a certain size shot (150). Your car does run good and I would be willing to bet it would run quicker with 3.89 gears on the same size shot if you raised your launch rpm from 6000 - 6300 -6500 on the kit as you would utilize the torque of the nitrous better and you would have your 9 sec timeslip.

It wont go back to the dyno, but regardless of what the dyno shows I know from past experiences and trial and error where my car likes to be shifted to provided its best et. I also know it will be harder to get the car off the line with that gear and a normal clutch. Also I am not suggesting any way will last longer than the other once you start spraying nitrous on stock pistons it is probably smart to accept that your engine is living on borrowed time. And thanks for enlightening me that nitrous makes alot of torque. Also I guess you consider shifting at 66~6700 rpm on n2o spining it to the moon???

I wasn't talking shift point, I was talking trap rpm. With your rod bolts 7000 is alot safer than stock ones for sure. When it comes to stick cars the right clutch for your combo is key regardless of n/a or nitrous as is the right tire, sidewall, pressure etc. You are right it is def alot hard to get a stick car working than auto especially with the tall 1st gear of the T56. Reducing race weight helps alot which you have done.

how would I be able to utilize the torque better? If I switched to a 3.89 I am loosing mechanical advantage off the line and picking up wheel speed. which all lead to worse 60ft times. maybe an auto could benefit from a 3.89 but not my car.

While your times are good, I just don't see the point in stressing a stock bottom end without even rod bolts by revving a motor with a LS6 intake, stock heads, and 1 3/4 pace setter's to 7000rpm.

Now if it had a Fast 92 on it at least, a set of ported 243's or aftermarket heads and a bigger set of headers in a more max output type set-up on the stock bottom end then it'd b worth wringing it to 7k to get the power.

Take my set-up for example since we are comparing. I have 4.11's with a TH400, but I have a ported Fast 92 which takes it out to 96 a 96mm throttle body, and 1 7/8" ARH headers with 5" extensions with v-bands at the track, but I am planning on trying a longer set of extensions with bullet's or one chamber's instead of my vibrant turbo mufflers and I turn it 7000-7200 for it's sweet spot.

It's been 10.29 on motor with a worse 660' time than my personal 660' best which is 6.38@105 vs. the 6.49@104 on the 10.29 run. Granted you have a 6 speed.

He has ARP bolts. That is one reason why I was saying go with less gear because of completely stock bottom end.

how would I be able to utilize the torque better? If I switched to a 3.89 I am loosing mechanical advantage off the line and picking up wheel speed. which all lead to worse 60ft times. maybe an auto could benefit from a 3.89 but not my car.

Unless my memory is failing me most folks will say wheel speed is important for getting a stick car off the line and getting good 60 ft times.

your memory is failing you via flawed logic, yes you need wheel speed but if you have TO MUCH wheel speed you are just doing a second burnout.

The difference in wheel speed @6000 rpm launch from 4.30 to 3.89 is +4 mph. I believe the right clutch , tire pressure , shock /suspension settings could control spin and 3.89 would allow a stock bottom end car to keep the revs down a few hundred on the big end. I would think that the difference in torque multiplication from the 4.30 and an extra 50 hp nitrous , but going down in gear would prob be a wash so don't see why tire spin could not be controlled with the right setup.

Oh yea ren987 this is a calm technical discussion. Definitely not rying to argue with you, just comparing theories and setups. I used to have a 6 speed formula and had it trapping really good , but sold it before I had a chance to do many suspension mods othe than the basics , control arms, torque arm, reloc brackets. Stock shocks. I was able to get it to 60 ft in the 1.5 on a decent track and it weighed 3600 raceweight. I was thinking about buying the car back and finishing the chassis, some weigh treduction, and putting a kit back on it. It did run 10.60 @132 on a 150 shot. LIke you there was a slight delay on the kit coming in. My launch rpm was 5500 and I had 3.89 with M/t et st. I think they were 27.5 inches tall. Bias ply , not drag radial.

I can see this isn't really going any where productive any more OP if you have any questions as to what worked for me I can certainly point you in the right direction my car went bottom 1.5x 60's stock weight, with stock worn out shocks on motor alone I never sprayed it with stock shocks so I can't speak for how it would have done. I am by no means an expert on the subject but I do know what is best for my set up and this has worked very well for me!

I shift at 7k NA and around 6700 on n2o there is more et with the 150 shot but I don't have the coin to drop on a nice adjustable clutch.

Whats your 1/8 mile et and mph on that pass?

I can see this isn't really going any where productive any more OP if you have any questions as to what worked for me I can certainly point you in the right direction my car went bottom 1.5x 60's stock weight, with stock worn out shocks on motor alone I never sprayed it with stock shocks so I can't speak for how it would have done. I am by no means an expert on the subject but I do know what is best for my set up and this has worked very well for me!

Ok. I see. Have a good day. YAAAH