C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Stronger IRS?

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Old Sep 26, 2012 | 10:15 PM
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Default Stronger IRS?

I've searched through google and through corvetteforums and find the only stronger rear suspension set up for a early c4 is go to a Dana 44 and that still doesn't hold for everyone. I can't find anything, do you guys know of anything else that will work stronger? If not I have thought and contepmlated a c6 IRS I know it will be a answer like "if you got more money than brains" or "anything can be done with enough money" but that doesn't help me. I would rather keep the IRS of this car than a solid axle. For the price of that solid axle I could pick up a used IRS I'm sure. So what do you think or how could I go about this?
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Old Sep 26, 2012 | 11:47 PM
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Its not worth worrying over until you have a REAL 500 RWHP thats capable of wiping out a dana...Most folks flirting with those numbers on the street have this figured out already because they either do NOT really have that kind of power OR they blew their dana to pieces and did what was necessary to get back in the game.

Beyond that, the 600 & up guys doing straight line stuff end up with the ford rears & a solid axle and stay off the twistys...Can;t have it both ways I'm afraid. If you want to put serious HP to the ground, pick your path...straight line require the solid rear, or the twistys that like the IRS where traction/grip in corners is more important than impressing the fans with tire smoke. There ARE a couple built rears available. Someone will jump in with the shop names and details, BUT again, if you want to keep it in one piece in the 1/4...find a ford rear to bolt in and forget it. To me, mating a ford part to a Corvette is a sin, criminal behavior but it works...
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Old Sep 27, 2012 | 01:20 AM
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It all depends on your power level and which level you want to stay at . . . Plans ?
Auto or Manual ? Autos are easier on the IRS, since you can preload.

But after some serious power , Solid is the way to go or play the time bomb game.
It a boom waiting to happen !
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Old Sep 27, 2012 | 04:21 AM
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Originally Posted by leesvet
Its not worth worrying over until you have a REAL 500 RWHP thats capable of wiping out a dana...
Not the Hp but the traction ( torque ) that kills them .
http://forums.corvetteforum.com/drag...post1571010479

Many on here have broken parts with much less Hp and a manual with good tires
The unis , spindles and halfshafts usually will break before the diff itself does
http://forums.corvetteforum.com/1574596578-post15.html

Many serious racers on here have spent up big upgrading rear parts only to have the next weakest link break ;
and most have stated that they should have fitted a solid rear much sooner rather than trying to
keep the IRS in one piece
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Old Sep 27, 2012 | 06:18 AM
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some good info in this thread and some bad. I can personally tell you that with 362rwhp and an automatic I have broke a dana 44 5 times. As rodj said, its torque and traction that takes them out.
As far as a stronger case, this is supposed to be better. http://www.newmancarcreations.com/products/
There are axle and stubshaft upgrades as well. What parts are you breaking?
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Old Sep 27, 2012 | 10:21 AM
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Originally Posted by 93 ragtop
I can personally tell you that with 362rwhp and an automatic I have broke a dana 44 5 times.

That's cruel !!! Good Hooking kills them then, what did you break first ?
If i break the Unis i will start to baby at the launches then...or i might quit racing , too dangerous for my pocket ! lol
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Old Sep 27, 2012 | 10:24 AM
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Originally Posted by 93 ragtop
some good info in this thread and some bad. I can personally tell you that with 362rwhp and an automatic I have broke a dana 44 5 times. As rodj said, its torque and traction that takes them out.
As far as a stronger case, this is supposed to be better. http://www.newmancarcreations.com/products/
There are axle and stubshaft upgrades as well. What parts are you breaking?


I'd agree with these opinions....
true, the HP can vary by hundreds...its the grip or the bite that stresses the rear to the point of exploding. Spinning wheels are not stressful on hard parts. Tires, sure. But when the tires grab and that stress is suddenly transmitted to the drivetrain...BOOM.

Gotta give the dana a little credit though....for a Diff designed for the street with a hi-torque engine from the beginning and a damn heavy car to haul around, they do pretty darn good to last as they do. Mines pushing 300K and never been apart besides a service every year. I don;t see the track much anymore, if at all, but its been there a few times with an engine that was in the 400 hp range...
(somewhat less now) to increase longivity in tough economic times
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Old Sep 27, 2012 | 01:06 PM
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I'm going to play around with modifying a Viper D44 for my ZR1 race car...

With a built LS7 going in it, the time from dropping the hammer with racing slicks to it going boom will be short...and expensive.

I've found good Viper Dana 44's for well under $1000...I'll just need to mock up the carrier to replace the batwing and such, but it should be a relatively easy exchange.

For a road-race/track car, a solid rear isn't an option for me.

Pinion snubbers can extend the life of a stock D44...but they'll eventually die even though you've put everything you can into making it last. The problem is the case is too thin around the pinion. Put some real load on the tires and the nose of the case flexes and breaks.

My stock rear in my Z07 is pushing 100k miles, and quite a few track miles on it. I equate that to me NOT drag racing (much) and keeping fresh fluids in it. I've owned it since new...so any/all abuse was done by me personally.

Should be fun to see how a Viper D44 fits...they are VERY beefy compared to ours.
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Old Sep 27, 2012 | 03:33 PM
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Originally Posted by Calderone
That's cruel !!! Good Hooking kills them then, what did you break first ?
lol
I have broke spider gears, the pin, broke the pinion gear, and of course, when you break a spider gear it usually gets into the ring and pinion and tears up alot more. Will just replaced the clutch packs that were wore out again. Oddly enough, I have never broke a universal joint, axle or shaft.
But again, the slicks are killing me.
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Old Sep 27, 2012 | 03:35 PM
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wow 93 what's your setup ?
i'm afraid that could happen to me
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Old Sep 27, 2012 | 03:43 PM
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We don't need a stronger IRS, I already pay enough taxes. Guess I should of read the thread first.
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Old Sep 27, 2012 | 04:37 PM
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[QUOTE=leesvet;1581935011....for a Diff designed for the street with a hi-torque engine from the beginning and a damn heavy car to haul around, they do pretty darn good to last as they do. [/QUOTE]

What heavy car and high-torque engine are you talking about?

Certainly not a stock C4.



Larry
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Old Sep 27, 2012 | 05:38 PM
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Originally Posted by rocco16
What heavy car and high-torque engine are you talking about?

Certainly not a stock C4.



Larry
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not easily impressed....
you don;t think 3300 lbs dry weight was alot for <300 hp in 1987?

and >300 lb/ft torque was unheard of back then...I'm not sure what you are comparing that to....

The dana rears were designed and produced 30 yrs ago to go in a car that was state of the art 25-30 yrs ago. I'm not comparing an 80s C4 to a 2013 ZR1....maybe thats what you're basing your opinion on...

in 1987-88 those specs were amazing and considered to be outrageous ...very high torque for that SBC. Last time anyone saw a car even close was something like a Chevy -II.

Its called "power to weight ratio"
not even in the same solar system as todays cars between huge hp gains and reduced weight on the chassis and body.

I'd forgot how damn heavy my C4 hood is...until I raised a C6 hood the other day..Like a feather compared to my 87 hood. The whole car is similar in the weight reduction and equally as aggressive in the hp improvements..its no wonder the late models are a bit quicker..stock form.

Back to the torque....many folks that do straight line racing STILL believe that a L98 C4 will jump MOST late model stockers...off the line because of the high low end torque. That don;t last long (60 ft)but its a big tribute to the car and the motor to even be able to jump something thats several hundred lbs lighter and several hundred hp stronger.
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Old Sep 27, 2012 | 05:58 PM
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Originally Posted by Calderone

It all depends on your power level and which level you want to stay at . . . Plans ?
Auto or Manual ? Autos are easier on the IRS, since you can preload.

But after some serious power , Solid is the way to go or play the time bomb game.
It a boom waiting to happen !
I am currently auto, I want to at least clip off a high 10 second pass at the 1/4 not on a regular basis but more than a couple times a year. And would like to get into road racing.

Originally Posted by 93 ragtop
some good info in this thread and some bad. I can personally tell you that with 362rwhp and an automatic I have broke a dana 44 5 times. As rodj said, its torque and traction that takes them out.
As far as a stronger case, this is supposed to be better. http://www.newmancarcreations.com/products/
There are axle and stubshaft upgrades as well. What parts are you breaking?
Currently I am not breaking anything, but I got the car with a bad u joint I think. Has a quiet but noticable thump sound from the right rear of the car.
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Old Sep 27, 2012 | 06:09 PM
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I say Go for it but ...

Do you have a light idea of what's required to get into the high 10's ? (Parts List and $budget$)
What's the plan (if you are planning something and i believe you are ! ) to get there ?
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Old Sep 27, 2012 | 11:33 PM
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Originally Posted by leesvet
Its called "power to weight ratio"
not even in the same solar system as todays cars between huge hp gains and reduced weight on the chassis and body.

I'd forgot how damn heavy my C4 hood is...until I raised a C6 hood the other day..Like a feather compared to my 87 hood. The whole car is similar in the weight reduction and equally as aggressive in the hp improvements..its no wonder the late models are a bit quicker..stock form.

be able to jump something thats several hundred lbs lighter and several hundred hp stronger.
1. A stock L98 isn't going to "jump anything" off the line. There is nothing special or magical about the low end tq or weight of an L98 'Vette. They 2.0 60' with the best of 'em!
2. The current 'Vette is not "several hundred pounds lighter" than an 80's C4
C4: http://auto.howstuffworks.com/1987-corvette1.htm
C6: http://www.leftlanenews.com/new-car-...pecifications/
What is noteworthy is that the C5/6 provide a more rigid/stronger frame, meet crash standards, and offer more content and features at basically the same weight. They don't weigh "several hundred pounds less".
3. The hood on a C6 is not the same; it's smaller. Try lifting a C6 hood...AND both it's fenders w/the inner fender wells too. Oh yeah...and the headlights.

Last edited by Tom400CFI; Sep 27, 2012 at 11:39 PM.
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Old Sep 27, 2012 | 11:53 PM
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glad its just an opinion............





I'll have to tell my C4 that it can't "jump" any of the super cars (arogant new vette drivers whom are superior and faster cause they were told they were...

But as far as prove it or shov it.....lets line 'em up
Mine C4-87 enhanced,,it goes...
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Old Sep 28, 2012 | 12:26 AM
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stock c4 , don't think so
enhanced c4 , modified c4 , i do think so !
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Old Sep 28, 2012 | 01:38 AM
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Originally Posted by leesvet
glad its just an opinion............





I'll have to tell my C4 that it can't "jump" any of the super cars (arogant new vette drivers whom are superior and faster cause they were told they were...

But as far as prove it or shov it.....lets line 'em up
Mine C4-87 enhanced,,it goes...
Huh?? Opinion? "Curb weight" is an objective, measurable quantity. Did ya look at the links that I posted for your reading pleasure? The C4 was actually lighter than the current C6! Fact.

The L98 makes less LOW rpm tq than the LT1 (per GM's own graphs). Fact. The LT1 makes less than the LS1 which is less than the LS2 and so on. Again, there is no magic in the L98. I'll concede that it will out do an L82.

As for Let's line 'em up. Sure. I'm always in but you WERE talking stock...now you're talking "enhanced"? What does that mean? HOw is it relevant to...anything?
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Old Sep 28, 2012 | 01:48 AM
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Viper rear may be stronger but all the other parts attached for a 10 sec ride will probably take a dump.

Many hav tried over and over and eventually post they wish they went to a straight axle the first time they broke. They really dont handle much worse than an IRS unless youre a road course fiend.
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