Your Bros C3s don't have that, they have a pinion mount, C4s use a C beam to connect the pinion side of the diff to the tailshaft of the tranny. it's soft of a back bone of the car, the tub is a sort of monocoque with the susp bolted under it (engine cradle shared w/ susp. cradle)

 

You're not the only one, I have a couple also. and I tried to tell him a bunch of posts back but was put down as being a critic. I even tried to give him an idea of how he could fab a pinion mount (post # 50)... oh well.

 

I dont think a torque arm will do it. Maybe.. But, if you look at the aftermarket frames that take C4 suspension, they all have a huge plate that bolts to the front of the diff where the cbeam would be.

Everyone and their grandma runs C4 suspension in non-c4's, cuz it looks cool I guess. Just normally they run aftermarket frames.

The cornering ability of the IRS may be slightly better than a thirdgen, however traction is an epic failure. A lot of the C4 guys are putting straight 9" axles in their cars..

-- Joe

 

Yeah, you can lead a horse to water but..

I've had my hands over every inch of numerous C4's. I'm very familar with the design, which IMO is flawed, but still, he's in trouble with that mounting solution. I don't think he understands the forces being applied here.

His best bet is to look at one of the aftermarket frames for the C3 guys, that uses a dana44 rear, so he gets a realistic understanding of what the rear end is going to do when hit hits the throttle.

As you know, when the cbeam is out of the car, the batwing can flex about 15 degrees up and down.. The bolts holding the batwing to the frame were not meant to keep it from spinning

-- Joe

 

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That won't get you anywhere.

I figured you might want some insight from guys who have run these rear ends.

Sorry we hurt your feelings.

No you are not.

Yeah, who needs those guys who have done this stuff before..

Good luck on the car.. I hope you don't die in it.

-- Joe

 

Ever own a C4?? Didn't think so. Traction is an epic failure. been there, done that, got the t-shirt.

Who is running 10s?


-- Joe

 

guys, obviously he isnt done yet and its a work in progress.

to call a rear suspension as accomplished as a c4 an "epic failure" in the traction department is well, kinda ignorant.
like said in (i believe) post #1, its not his goal to drag race... therefore the undesireable characteristics an IRS exhibits in a drag racing scenario are irrelevant.

as for securing the pinion, again, he ISNT DONE!
not sure what you dont understand about this fact.

seems to me that mounting it to the cage is a mighty fine idea and will work great as long as the cage is properly braced.
all it would take is a good solid bar running perpendicular to the pinion (not the floor, the pinion) going to a cross in the cage, with cross braces above... this should MORE than suffice.

as for the batwing flexing, 15* (i believe that was the number you pulled out of thin air)
HAH
really?
really?
15*
really?

c'mon, this is just rediculous

 

How would you know? Do you own a C4?? They all wheel hop, the camber changes when the suspension unloads and loads. Maybe you should spend some time talking to C4 owners before you call someone ignorant.

True, but I'm still trying to understand what all this work will get him.


What? It floats between the mounts. Take the Cbeam off a C4, you can move the pinion up and down about 15 degrees.

I owned one of these cars until a few months ago, and built a few other ones, including rebuilding the dana rears on these cars.

http://members.cisdi.com/~anesthes/p...rear-apart.JPG
http://members.cisdi.com/~anesthes/p...t/tail-air.JPG


I think you might have just finished the 2nd or 3rd grade the first time I had one of these cars apart.

-- Joe

 

So you think the C4 suspension is the be all end all? I have news for you, there's a severe jacking problem under cornering with these because of the roll center height, it's notorious especially on the earlier cars. The later suspensions are different in geometry (yes, they are NOT the same through all the years), the toe control depends on limiting angular effect by using long toe rods with a central mount. This is not the best way to do it, it's a cheaper way to do it and toe control suffers with susp. travel the more it gets away from the halfshafts being around horizontal. There's more but you people aren't interested anyway since you think all we do is criticize. You could actually learn a thing or 2. That's what I hate about these forums, ignorant fools who think someone else couldn't possibly know a thing or 2 about something.

As for the stupid comment that GM designed this without our help, actually GM got the idea from Bob Riley/Protofab. He designed this type suspension for the C3 race cars. Greenwood had a better but similar setup with better toe control (true length stuff that was suited better for the IRS geometry)

As for knowing stuff about these things I designed and built my own IRS TWICE!!! I 1st built an IRS, resembling the Greenwood setup but before installing it I designed and built a custom unequal double a arm suspension for the rear using the super Dana 44 as the center section, it's what you see in the pics in post #50.

As for the batwing flexing, the fact that you don't know what you are talking about shows here. What he means is that without a pinion support the pinion hangs down, this is because the batwing uses large bushings on the ends with a sleeve inside, these stock rubber bushings have a lot of compliance and do NOT hold the pinion angle. It has nothing to do with batwing flexing.

 

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Nobody degraded your work. We told you what would happen if you didn't anchor the nose of the diff. Been there, done that. Your the one getting all heated up and upset over it.

Well, I'm sorry to hurt your feelings.

OK.

I was posting to give insight on where I thought it might be an issue. While others were concerned with the size of the brackets to the rear, my concern was simply the lack of an achor point on the diff to replace what GM used as a cbeam.

I also shared my feelings on the wheel hop issues of the C4 IRS, as I've owned those cars, wrenched 'em, raced 'em, modified them.

As you pointed out, in post 56 you said: "For the pinion mount I'm open to suggestions."

Apparently you didn't really mean it, and this was not open for discussion.

Again, Sorry I hurt your feelings. I'll leave your thread alone now.

-- Joe

 

I think its cool as **** that you are doing this...and would do it to my car in a heartbeat if I didn't need my back seats. My 96 LT4 383 made 500 flywheel horsepower. I had 9 inch wide rims on the back with drag radials. I never had wheel hop problems at all. When the car hooked it launched hard. The only Vettes I have seen with wheel hop problems are C5's and C6's. I have heard of them hoping so bad the break.

Some guys forget that its all about backyard wrenching on thirdgen, because most of us are poor boys.....

 

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LOL.. ill shoot..im telling you..I will ..1 more stepp..ill do it!!

I could not get a stock rear end to hold up to any 1.45 60' times
(got bags of steel for Proof)big nasty chunks...sweet!!

at the same time i dont use anything on my pinon
or within 13" of it. dumped that lasty long arm thing ..yuck

had to go to a 9" to hold up to 490Hp and 1.54 60" times
makes for better driffting (for me)

i think what he's doing is cool. looks good..

on a side note:
when..and if i had to tell a guy. i was going to shoot them on 5..
i would shoot them on 2...Just me..lol

 

lol at arcticwhiteZ

im sorry that this thread got filled with garbage.
i agree that a moderator should know better than to get into bickering matches.

either way, i'd love to see the finished product, so please dont delete the thread.
if you must, email me all the pics with captions, because i would love to see how it was finally done.

 

yes Keep this posted..dont take it down..

 

its never gonna work. i mean just look at all those pieces of metal held together with JB weld!! dont you know what your doing??!??!!?!?!?! GAHHH!!

jk. looks good. your not done yet. lot of work to do. cant wait to see it when its done (itll never be done btw ) and please post some pics soon. i for one am being very patient.

dont delete the thread. its not worth deleting cause some people dont like the way your doing things (EVERY thread is like this anymore) just roll it off your back and keep up the good work.

 

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congrats on the wedding!
its always funny to realize that people in "cyber world" have real lives just as much as i do.
i guess its one of those things that i dont think about lol.


ive done some research on the C4 rear end and realized that this is going to be much cooler than i originally thought it would be...
rock on man!

and as for any wheelhop issues you may end up having, i am positive that there will be an aftermarket solution.
i mean, look how many people make LCARBS for our cars. C4's are much more supported and there is sure to be a solution if you run into a problem

 

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that's the sole reason I post very little projects I have done over the years online. It gets you no where but frustrated. Keep up the good work, and you will be chasing cones in no time. Be prepared to field some of my questions in the future though lol

 

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so you are using 1/4" steel for your batwing mounts?
i think that will be MORE THAN sufficient by the looks of it.
i happen to know from experience that 1/2" steel will easily hold up to 1200 lbs braced similarly to the way yours is, but much longer and cantilevered off to the side by 18".

the weak point in my design was just where the triangle brace mounted to the base, or in your case, the floor (car)
i could have gotten by with thinner metal, but solidworks said that it would break there, and i tend to agree due to the massive change in cross section leading to a big stress concentration point.
if you looked at the graph it was literally all blue except for a single point of red with stress radiating outwards.

i had to build an injection molding mold loader for my work, and unless i am seriously underestimating the forces involved, you should be fine.

in your case, the brace is at less of an angle so i would imagine that you would be ok.
interesting point however is that in some cases you can actually make a structure stronger by removing material.
in some cases this will reduce your stress concentration factor and make the structure stronger

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im still not clear on one thing though. are you using a panhard bar or not?
i cant see where it would be needed except for more bulletproofing.

as for making this into a kit, i cannot see that happening easily. look at all the cutting you had to do on the car and imagine trying to make a template for it...
not easy i think

 

i see no need for a panhard, its an irs, no side to side movement.

sure you can make a kit, it will be the irs setup, a mig welder, sawzall, and a pile of sheelmetal

 

dude, seriously......


um....the center section bolts to the car, no need for a panhard rod engineer guy. He will have no place to attach it, or have any need for it.

remember, he is shoving 11" wide rims under the car. They will fit nicely up under the fender lips. If he decided to run 9" wide rims, or if he wanted them sticking out a bit, he could have got away with not modifing the inner wheel well. This could be a kit. Hell they sell weld up your own header kits...

 

i just thought i remembered someone saying something about a panhard bar thats all... no need to get all twisted up over it.

not sure i understand what you meant by this

as for the kit, am not sure how you would make it a kit where the control arms for the IRS mount to the body.
looked to me like he cut that area out and completely re-did it so that it would fit.

heck, if he wants to make a kit, then go for it, but to me it seems like a ton more work that wouldnt really benifit anyone...
i mean have you ever been part of a GP on this board?
they are usually total failures with about 25 people showing interest until its time to pay then all of a sudden its down to 2 and the manufacturer ends up giving 2-3% off out of pity...

 

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I still dont understand why people do this. There is a button at the top of the page to subscribe to a thread so you dont post usless crap.

I have been following the thread for a long time now BTW, I always wanted to do this same project but I never had the facilities to do it.

 

a GP? for what? He can build a kit, with brackets, gussets, some prefabbed sections, and a detailed instruction book, and TA-DA...he has a kit. You source your own rearend. Roll cages come in kits as well. They dont spring out of the box and jump into your car, It takes careful planning and thought, as well as some basic fabrication skills. They are also very intrusive to the interior of a car, just like his IRS.

 

thats Jay from Fbody motor sports 97 i believe trans am that they made back to a formula body and a sick motor i havent seen it in a few yrs but that think is really nice i seen it in person wen i lived in NC

 

Very nice fabrication work A+ all the way.

 

I remember back some time in the 90's, a blue thirdgen T/A won the Real Street Eliminator competition in Car Craft Magazine with a transplanted corvette IRS. It was blue

 

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I'm positive. I recently tossed some of my car mags so I'm not positive on the year or issue, but I think it might have been '93 or '94. One of the first years for the RSE event.

The car was on the cover of the mag, I believe it was a medium to light metallic blue. Had 17" Centrelines. I'm not having any luck with a search though.

 

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That's quite the impressive amount of fab/labor. Kudos for documenting the venture, too.
I know it would take a massive amount of cold beverages to do something like that to my 'bird. It took me enough just to gather the courage to cut perfect doors for flush handles.
I'll defiantly be looking in again when you get closer to finished.
Even if there's no gain.... it sure as hell looks cool.

 

buff out all that rear end..clear it. that would look fantastic!.

when your done getting set up and treeked

 

1MeanZ, that's looking pretty slick, keep us posted on how it performs

 

looking good, i didnt notice, but are you keeping the leaf spring setup or using coilovers?

 

I believe he said earlier he plans to use coilovers.

 

If I remember correctly, he will be using the leaf spring because the coilovers didn't line up with the stock upper shock mount and he didn't feel the need to make a custom upper shock mount.

 

I just went back to check and in the pics it looks like he already has the transverse spring installed, if I'm seeing things correctly.

 

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on a scale of 1 to 10 how hard do you think the was to do? (1=lowest 10=highest)
im asking because i might give it a try and i basicely want to know what im getting into.

i really like how this is coming along and you are doing a great job.

 

now just pull it out and polish that sucker to a mirror finish.
lookin great.
and to everyone who asked, that black thing on the back would be a transverse leaf spring

 

I saw that, its a neat idea

 

yeah, it stores a lot of energy (apparently more than conventional coil springs) is somewhat variable rate, and acts as a swaybar as well...

 

Great work so far, this is one of the mods I have been researching for my car, and like you I couldn't find much except for the pis from the zues site. Keep us posted on progress and how it drives when its done