[15886]

Whats the rear gear ratio for a nitrous car 10.5 to have? I hear 3.73 and under they say 4.10s are to much for a nitrous car 10.5 TIRE

 

[mAydAy]

Depends on the rest of the combo....

 

[John Phillips]

Whats your first gear ratio?Car weight.How hard are you planning on hitting it out of the hole?

 

[15886]

1.74, 3000,29.5x10.5,350hp single fogger,sbc 436ci

 

[The Joker]

with a 29.5 the 4.10 would be fine if you run a small tire then i would go with a .373

 

[John Phillips]

The 4.10 and a 1.60 first gear would be nice but that hits the bank account kinda hard.You could get pretty aggressive on the launch and not pull the rpm's down as much on the shift.

 

[CAMPBELLRACING]

good info here im fixing to build a nitrous outlaw radial no boost car with at 3000lb , turbo 400 2.48,315 radial, 604 bbf with three kits prob 4-6oo on the three kits total , i was wondering what kind of gear ratio i might have to run i was thinking maybe 3.89?s shifting at 7400 in 1/8 mile

 

[dover1320]

good info here im fixing to build a nitrous outlaw radial no boost car with at 3000lb , turbo 400 2.48,315 radial, 604 bbf with three kits prob 4-6oo on the three kits total , i was wondering what kind of gear ratio i might have to run i was thinking maybe 3.89?s shifting at 7400 in 1/8 mile

Get rid of the 400 and put in a glide.

 

[Monte Smith]

That 2.48 low, on a big block with spray and a radial, is not going to work. Put it like this, our 632 had a 1.69 in the trans and a 3.70 gear.........it was still a beast to manage on marginal tracks and we were progressing a fairly small jet on the first kit.

Monte

 

[z289sec]

good info here im fixing to build a nitrous outlaw radial no boost car with at 3000lb , turbo 400 2.48,315 radial, 604 bbf with three kits prob 4-6oo on the three kits total , i was wondering what kind of gear ratio i might have to run i was thinking maybe 3.89?s shifting at 7400 in 1/8 mile

If you are gonna try and keep that T-400 better try about a 2.73, or a 3.08



For the O.P. I agree a 4.10 should work well with a 29.5 slick.

 

[cobrasan]

how about a 2900lb. car 408" glide with a 1.80 first gear. two kits spraying aprox. 400hp shot total on a 275 radial. This will be a 1/8th mile car.

 

[z289sec]

how about a 2900lb. car 408" glide with a 1.80 first gear. two kits spraying aprox. 400hp shot total on a 275 radial. This will be a 1/8th mile car.

If it were me and depending on the rpm range of the motor I would say a 3.70-3.89 would work well.

I run a 3.89 with a 1.69 first gear on my 275 car, 427sbc sb2.2 heads with a .036 pill in a single fogger.

 

[LSxBu]

2.48 first gear 400 turbo.. 4.10 rear..
1978 malibu 3606 with driver.. 408lsx 275/60 radial pro.stinger 3 plate etc... thinking on 3.55s? Like to leave on 200 without a progressor...cut a 1.43 sixty off the footbrake on 150 so far un prepped track...

 

[slowstang]

2.48 first gear 400 turbo.. 4.10 rear..
1978 malibu 3606 with driver.. 408lsx 275/60 radial pro.stinger 3 plate etc... thinking on 3.55s? Like to leave on 200 without a progressor...cut a 1.43 sixty off the footbrake on 150 so far un prepped track...

just be careful when you go numerically low like 355 from say 4.10 it will lug engine in high gear,this is hell on a nitrous engine.

 

[LSxBu]

I’m 1/8 mile only...trying to make it more street friendly i drive it more than race it...didnt think a 3.73 would be worth the trouble?

 

[SBP436]

1.74, 3000,29.5x10.5,350hp single fogger,sbc 436ci

Im 1.80,3140 29.0x10.5,200hp plate 4:56 [email protected] 1/8

 

[LSxBu]

2.48 first gear 400 turbo.. 4.10 rear..
1978 malibu 3606 with driver.. 408lsx 275/60 radial pro.stinger 3 plate etc... thinking on 3.55s? Like to leave on 200 without a progressor...cut a 1.43 sixty off the footbrake on 150 so far un prepped track...

Anyone else???

 

[fofo]

33x10.5Wx16 tire, 2960#, Fulton 706, 69 Camaro back half stock front suspension. 1.80 Glide, 4.57 rear gear.

There is no one set answer to the question, but here are the key criteria to determine the correct answer, IMO;

1- Power being made & RPM characteristics of the engine combo;
2- Weight of car;
3- 1/8 or 1/4;
4- Converter characteristics;
5- Suspension efficiency (4 link, shocks, weight %s, etc.);

Example, my Coan converter is very tight. The low 4.57 rear gear lugs the motor, so because of those 2 factors, I can spray it "hard & early". My 1-2 shift with a Glide will come relatively soon, & the ERPM & DRPM will go 1:1 during the run, before the 1/8. Lastly my engine will be turning close to 7400-7500 at the 1/8 with the DRPM being equal to or more than that #. Once I loosen the converter stator to help with consistency in launching the car in tight track conditions, this should be a very efficient combo.

As you can see, if the Coan Converter was slipping just 10% at the 1/8, say 750 RPMs, I could not run this 4.57 rear gear, or I'd be crossing at about 8200, & I do not want to spin the engine that high.

Good luck to you.

 

[Billy Stocklin]

Probably 6.50-6.80. The more rear gear the better w small block. Keeps the engine revved up in high gear so it's less likely to blow up.

 

[blue ten]

Probably 6.50-6.80. The more rear gear the better w small block. Keeps the engine revved up in high gear so it's less likely to blow up.

You mean slr needs to be 6.5 to 6.8? right???