Hey,

Trying to figure out what gear ratio to run in my axles.

Setup is a 2 seat buggy, S&N Fab 5.7l cammed Chevy engine, 4L60E tranny, atlas 3.0

Going to run 40" maxxis or Baja t/a tires.

Im new to racing and want to know what ratio gears people are running in their axles?

Ive hear 4.10 up to 4.88

Whats the preference, when trying to go fast?

I tried searching but got nothing.

Taylor

what performance are you looking to get. unless you have a rediculously high revving motor where top end speed is unltimately important I would go with a little more grunt. KOH and rockracing is a whole bunch of short drag races. I ran 6.50's with my 4.3 motor last year and ran 5.13's with the L33 5.3.

What race?

I would say somewhere between 583-620'ish

edit:
I would drop tire size considerably if your going to try and desert race a rock crawler.

I'm guessing you're the guy who called Jason recently about a plate subframed chassis?

my car with an LQ9 with a few goodies run's 4.88's and the motor makes more than enough power to spin all 4 tires on moderate acceleration in the desert on 40's.

sell it to ya $55k :grinpimp:

I'm guessing you're the guy who called Jason recently about a plate subframed chassis?

my car with an LQ9 with a few goodies run's 4.88's and the motor makes more than enough power to spin all 4 tires on moderate acceleration in the desert on 40's.

sell it to ya $55k :grinpimp:

yep:smokin:

What did you average for top speed?

I want to build my own buggy:flipoff2:, but i would buy yours in a heartbeat if i had that much right now:D

yep:smokin:

What did you average for top speed?

I want to build my own buggy:flipoff2:, but i would buy yours in a heartbeat if i had that much right now:D



in KOH, with the car having 5 miles on it, and 20 min of seat time before the race, we hit a high of 70ish? but that was with the origional 4.8l it was first built with. the downfall with the small motor was it's capable of 58mph in 1st gear, and ya had to upshift at 55 to have any power in 2nd.

the LQ9 i don't rev past 5k, it pulls just as hard in 2nd shifting at 5k as it does at 6500.

when we raced the MORE500, the gps showed an average in the mid 30's, it varied by driver a bit, and the high recall was in the 70's again. being a dana 60 solid front axle, unsprung weight starts to limit how fast you can really push the car without killing it, or yourself.

That issue will be changing before next season, i assure you of that :)

LS1/TH350/Atlas 3.8/4.88's/39" BFG's

We hit a top of 81mph on GPS in KOH on the lakebed. I love mine in highside. I've barely had it in 3rd in highside and really USING it though. KOH and several pavement runs is about it. That tells me I could possibly go to something a bit steeper in the axles but I dont need more gearing once in Low Side.

In lowside, its great for crawling but too steep in my opinion for XRRA, I bounce off the rev limiter for what seems like the whole course. For the short course races I wish I had the 3.0 Atlas, but then crawling would suck when not competeing. So its a compromise.

I think I have a best of both worlds compromised setup. Low enough to crawl, but not too low, high enough to haul ass. Its the in the middle thats compromised which for me is XRRA racing, short course haul ass.

LS1/TH350/Atlas 3.8/4.88's/39" BFG's




same setup. the crawl ratio kicks ass! though the rev limiter is 38mph in 3rd gear low.

my new housings will have 5.43's in them, and i'll be swapping to a 3.0 atlas. takes me from 46 to 41 for crawling, and will get me 41mph in low now. but lose a fair bit of unsprung weight.

my biggest reason for the 4.88's is i have a rear HP60! and have already damaged one gearset.


ok, back on topic. I had origionally planned to do 5.83 gears with my 3.0 atlas, but for short course/rock racing, i'd probably go closer to a 5.29/5.43 if i was doing 9's, and 5.13/5.38 with a 60.

I think a 5.40 or so with a 4 speed trans with converter lockup is the ticket. nice and low to get going but it'll not wind out too much on top. I wish I had chosen my parts differently the first time around and done a 4l80 instead of a th400 and 5.40 gears instead of 4.88.

As has been said, shoot for just above the 5 mark with gears, like a 5.13. The 3.0 atlas will be complimented nicely with the 5.xx in low on the rocks with 40's, and you'll actually be able to use 3rd gear in high side with the 40's. Should have legs to get you to 100, but you shouldn't need it unless on pavement, you have a solid axle!

I have 4.56 gears atlas 3.8 and a 700r4 I have little experience at speed, but it seems to work pretty good in high range. I had a tired old 350 and had a hard time getting 3rd gear in the flat fast sections of the RCQ. My rig is around 4000# on 39 krawlers. Low range it works great. Plenty of gear in first and reverse but at the smae time, 4000RPM low range overdrive is around 37 mph.

I have 4.88s with a 4.8 700r4 and a 4.3 atlas II. I wish for a little more gear in high range some times but with the 4 speed I get 45mph in low range 4th for those rock to rock sprints.

DSIs rig pulls through 1st 2nd then pulls 3rd with no problems. with that much motor I would stay with 4.88s but I like to short shift anyway.

besides who past who on the lake bed?

wayne

I currently have a LQ4, th350, 3.8, and 5.13 diffs with 39's and yeah it revs out 3rd in low range way too quick. My biggest complaint though is how fast i am going when i click it in to 3rd gear in high range, like 70mph! The thing is geared to do like 120! I am thinking about going to a 4spd atlas this winter. I only need this rig to do 85 but i want it to use all of every gear to get there (if that makes any sense):homer:

Greg

Been doing some thinking and seems like the best setup would be a 4l60 and a 2.0 atlas. With 5.13 it would have a top speed of around 90 in od and still have a crawl ratio of 32-1 in first. If you needed lower than that for crawling going with a 4spd atlas is a good option. Just my thoughts....

Diff wise i would go with a 5.13 or 5.40. Those seem to have the best strength.

This is a handy little calculator http://www.wallaceracing.com/gear-speed.php

Not accounting for tire distortion I'm geared to do about 160mph :lmao: I sure as hell don't have a motor that can push it anywhere near that though :lmao:

huss, you talking about running the 4L60 and 2.0 t-case in low range all the time? i did some numbers on that myself and the cool thing is if you want to pick up the top speed a little you just drop to a stronger 4.56 or 4.88 axle gear. i think you need another gearbox in front of the T case though for low range.

Weren't there rumors that scherer or slawson ran like that at KOH? I mean with the t-case in low all the time then just used the planet box for "crawling".

huss, you talking about running the 4L60 and 2.0 t-case in low range all the time? i did some numbers on that myself and the cool thing is if you want to pick up the top speed a little you just drop to a stronger 4.56 or 4.88 axle gear. i think you need another gearbox in front of the T case though for low range.

Weren't there rumors that scherer or slawson ran like that at KOH? I mean with the t-case in low all the time then just used the planet box for "crawling".


Randy did with his 4speed atlas and 4L60?. Jason with a 3speed trans and a 2speed atlas i beleive he ran high and low both.

Or if you want more top speed put it in high range....:smokin: With the 2.0 atlas paired with the 3.1 1st gear that the 4l60 has it would be very similar to my 2nd gear in my th350 and the .7 od would still let me get to 93 mph at 6000rpm. Like i said i only want the rig to do 80 but i want it to pull hard in every gear to get there.