Nailz

Im building a 500+ hp stroker that has me scared of breaking my rearend :confused:

According to a mechanic i know who has built some drag cars says i need to keep that vette off the drag strip with 500+ hp because ill be doing nothing but busting inner axles.

Is this all true??? - i would like to know from the people who actually know vettes instead of this Mechanic.

Gordonm

As long as you don't use slicks you should be OK. If you use slicks you will need to upgrade to some better components. There are plenty of people here running 500+ HP cars and the rears are OK

Nailz

Hey man thanks alot for the info :)

My engine is almost ready to go in - My inner axles are new and my differential has less than 5,000 miles on it so its not like anything is ancient back there :)

Monty

As long as everything is solid (ujoints), and in good shape, it's been my experience that you'll be fine as long as you stick to street tires - no slicks - and you use a sane driving style. No 4000rpm clutch drop launches. Feather it off the line, then punch it and hold on!

Have fun and good luck.

Matt M

Come on guys! I run slicks all the time making 650 horsepower and over 600 ft lbs of torque. I have acheived 1.40 sixty foots and can lift the front tires on a launch (very small amount :) ) I run an independant rear suspension and go to the track as much as possible. I have had zero failures since I built up the rearend assembly (3 years).
Yeah, the stock stuff broke all the time, but anyone building a 500+ horse engine should build the drivetrain to handle it.



Matt


[Modified by Matt M, 4:29 AM 1/9/2002]

63Banshee

No doubt. What parts did you use for the rear? I may stick with an i.r.s. for project Banshee.

L8r,
DJ

Matt M

Forged side yokes (I think they are made by International Tool and Axle)
Tom's forged spindles
Larger diameter OEM half-shafts
Spicer non-greaseable U-joints
Stock center section with 4.11's
IPS modified VB&P traction bar
OEM 1985 fiberglass rear spring
Koni shocks
VanSteel double-offset trailing arms

Matt

DeenHylton

Matt, did you have Tom's install the steel cap and larger bolts to hold the carrier in? Sounds like you have around $2,500-3,000 or better in your rear upgrades. If I do all the assembly and buy the HD parts it looks like it will cost $1,000 just to upgrade the center section itself (including Toms' side yokes which are half the price of the tool steel ones).

SmokedTires

I just ordered Tom's 30 spline polished posi with a large crosspin & 30 spline side yoke axles. After snapping the inner axle last year with my (street tires) I found that the posi case had a small crack near the crosspin hole.

Stingy74

There's an area within the stock carrier that needs to be shot peened for added strength. I guess they are very prove to cracking.

PS: SmokedTires, your chances of that happening with an automatic would have been greatly reduced. Standards are just so damn hard on parts!!:sad:




[Modified by Stingy74, 12:06 PM 1/9/2002]

Nailz

what sucks is i just dont have the money right now to do anything more to my rearend - im only 18 with a part time job , i pretty much dumped all my money i had into that motor.

jimduchek

Suggest you keep your tires around 255-265 series at MOST with that much power and a stock rear. Yeah, you're going to have a lot of traction problems till you learn the launch. But remember, when you drop the clutch, you have an engine going 3000 rpm, and a drivetrain going 0 rpm. SOMETHING WILL BREAK. Always. Every launch. Something has to. The idea is to make sure that your weakest link is the tires' connection to the strip. It's OK if that breaks. :) :smash: And then, either slowly start going with bigger tires as you upgrade rear end parts, or save up and do the whole rear + bigger tires at once. Oh. Yeah. Driveshaft and half-shaft loops, Lakewood bellhousing or something of that sort as well. Safety first. Not just a 'good idea', they're a Good Idea.
Drivetrain breaking doesn't suck very much when put up against YOU breaking...

Jim

gkull

I agree with matt. I run a stiff rear spring and smart struts from Vette brakes. I bought many years ago the custom forged yokes from Mid America $225 each. The posi unit always goes, so I have the $685 unt from tom's. Hybreds used to fail me once a year using 9-10.5 slicks and street driving with my 17/315's

Matt M

Yes, I forgot to mention- I run an automatic. I used to run a Doug Nash 5 speed/centerforce clutch. It was a lot of fun, but it was rough on drive train parts!

I run a stock differential and I beleive the parts in it are stock other than the side yokes. The differential was built by Gary at Caledonia Corvette. I think that the carrier for 4.11's and higher is stronger than the carrier for numerically lower gears. Anyone know about this?

Here's my costs:
rebuilt 4.11 differential $500
side yokes $450
T arms/bearings/spindles $1200
traction bar $50
used 1985 fiberglass spring $25
U-joints $50?
heavy duty cover came on car

so your guess was good- it was over $2000

gkull, you run 315's too? Thats what I run on the street- at least when I'm not too lazy to take the slicks back off. :)

Matt

DeenHylton

Even running an automatic will break/crack the differential at the pin area...it's just a matter of time when running slicks. I run an automatic without a transbrake and a blower (blowers are supposed to be gentler on the drive train than nitrous). I also know an older gent at the track who is running a 406 in. small block with a small stall converter (1500 stall) and 12" wide street style "slicks"...he told me he has broken his stock rear end three times over the last few years (don't recall which parts broke). He runs low 12's. Deen

Nailz

I also have a stiffer mono spring in the rear, i bought that performance suspension from ecklers that put better struts shocks and sway bars.
Im also running a T-10 4-speed and i just recently put a Centerforce dual friction clutch kit in. This car is my daily driver - but i want to take it to the track every once in a while.

I would like to be able to come home from the track with atleast a high 12 sec timeslip and prove my dad wrong about not being able to drive a 12 sec car everday hehe


[Modified by Nailz, 3:41 PM 1/10/2002]

Nailz

OH!! and not to mention have the baddest car at my school :chevy

High 12's would put me on top of those Stang boys at my school :p:


[Modified by Nailz, 3:45 PM 1/10/2002]

gkull

Smoked tires has one step higher quality Posi than me with the 30 spline. Posi units start to elongate the hole where the pin goes though and eventually it rips the pin out and the posi case breaks. It's not a big deal you can limp it home if you can stand the noise.

Mid America sells the complete diff. So since I knew that they were just the middle man I called up and said, "who can I talk to about warranty repair?" So they gave me the number down in Houston. I outright bought a 4.11 rear with Richmond gears, steel caps heavy cover................ So anyway with the yokes you get @$2000 in just the Pumpkin. I've since changed to Tom's posi units. My 4.11 is 14 or more years old now. My original 3.55 gears pumkin went in a dumpster at about 50K miles. To make them last you want to limit verticle travel of your rear wheels. Stiff springs - good shocks - 5/8ths or 3/4 rear sway and Smart struts.

If 79 is a L-82 stock with just exhaust mods it won't do under mid 13's. The Hawaiin boy's are the bench marks for drag racing and you'll find that it costs money to have 12 ish time slips.


[Modified by gkull, 10:13 AM 1/10/2002]


[Modified by gkull, 12:39 PM 1/10/2002]

ZD75blue

half shaft and drive shaft loops, will help you find the limits :reddevil

Nailz

Its getting a 500+ hp 383 in it soon - thats where i get the idea of running 12's



[Modified by Nailz, 7:12 PM 1/10/2002]