IRS How to - Page 5 - Suspension and Brake Forum

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Re: IRS How to
Monday, October 24, 2005 6:07 PM
hahaha

your still on 4....... im on 5




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap


Re: IRS How to
Monday, October 24, 2005 6:11 PM
oh yea...... nice pics...... every time I see a Grand AM GT or Alero, I fantasize about stealing the IRS off of it.......




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap

Re: IRS How to
Monday, October 24, 2005 6:30 PM
SpeedRacerZ wrote:

hahaha

your still on 4....... im on 5


Bah, i sux0rs.

But I have IRS now





Re: IRS How to
Monday, October 24, 2005 7:14 PM
Friends a dumb question, what other cars could have the same or similar and j-body usable IRS setup? what about Luminas, Impalas, Neon?


___________________________
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Visit my cardomain site !!!

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Re: IRS How to
Monday, October 24, 2005 7:14 PM
GM obviously used the spacers for a reason


but good job


when you gonna do mine john ??







Re: IRS How to
Monday, October 24, 2005 9:01 PM
Eliot wrote:

Friends a dumb question, what other cars could have the same or similar and j-body usable IRS setup? what about Luminas, Impalas, Neon?


Impalas (w-bodies) have IRS. But doesn't fit our much smaller cars. Neon, wtf? Luminas had a torsion bar iirc. If we knew of other cars, we'd try them. Go take a look around a yard.

Lenko: On the camber issue, is that too much positive or negative? Looks like positive in the pics, but could be the angle.



Re: IRS How to
Monday, October 24, 2005 11:09 PM
Other cars... no idea. Don't care to find out, either. This was cheap and couldn't have been much easier.

I swear the rear frame rails (attached to the unibody... I know... I know..) are identical between J and N cars... I just have no proof. But everything is in the same spots, except for holes for this cross-member. Everything else.. measurements... it's all the same. Of course.. the spare tire well is deeper on the J-car for whatever reason...

To me... the wheels are sitting like this / \ (but only ever so slightly). I'll take it to the alignment shop as soon as I have brake lines... then I'll give you guys some numbers.





Re: IRS How to
Tuesday, October 25, 2005 8:21 AM
IRS...yum. If I didn't autocross I'd definitely think about this mod more.

As it is, this would throw my car out of street mod (changing the suspension pick-up points). Not even sure where it would put me, either a Prepared (not Street Prepared) or a straight Modified class....eek. Well...I'm not competitive in SM anyway, so I really have nothing to lose going to an even crazier class.

Oh well, I might do it eventually anyway, as my fiero may end up taking over autocross duties once I get its suspension properly refreshed (yay for 20 year old parts).


-------------------------------------------------
Sleeper style, they don't see it coming that way.
Re: IRS How to
Tuesday, October 25, 2005 2:40 PM
C.T.S wrote:

Eliot wrote:

Friends a dumb question, what other cars could have the same or similar and j-body usable IRS setup? what about Luminas, Impalas, Neon?


Impalas (w-bodies) have IRS. But doesn't fit our much smaller cars. Neon, wtf? Luminas had a torsion bar iirc. If we knew of other cars, we'd try them. Go take a look around a yard.


I ask because we don't have Grand AM or Aleros in my country.

Thanks,


___________________________
MAKING MY DREAMS A REALITY
Visit my cardomain site !!!

ELIOT. Now.....boosted.

Re: IRS How to
Tuesday, October 25, 2005 5:53 PM
looks like you might have to make a trip to florida......

unless you have the Chevy Malibu??? same body.......... I think even the Olds Cutlass (98-99ish) is on the same platform......




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap

Re: IRS How to
Tuesday, October 25, 2005 8:44 PM
Yeah the malibu has the IRS setup, but with drum brakes. Flordia doesn't sound so bad, but I imagine customs would be a bitch.




Re: IRS How to
Wednesday, October 26, 2005 12:07 AM
im sure you could find a N-body pretty cheap in southern Fl

lol







Re: IRS How to
Wednesday, October 26, 2005 6:52 AM
Okay, I have a few questions before I run out and grab the parts for myself.

1) Is the unibody material of similar thickness from the J body to the N-body?

2) has the track width changed substantially? what was it before what is it now?

3) Obviously, the double drilled rims are now a reguriment as the N-bodies have a different hub patterm?

4) Could you not use the upper J-body mount in lieu of the n-body? or did you redrill the upper surface to accomodate the N-body mount? this would alleviate the problem with having to change the springs?

5) Would the struts form the Cavalier fit on the n-body lower suspesion point? Or would it be eaier to use Koni yellows, and the just install them in the N-body strut housings?

As for autoX and this mod, have been talking to a friedn of mine, seems this puts you up about three classes (E mod I believe). Would be great on the roads though.

Lenko would love to have some shots with the car sitting on the ground from the rear to show the width of the rear track now. and how the tires look inside the fender openings and lips.....



Re: IRS How to
Wednesday, October 26, 2005 7:12 AM
Marchi1: If your seriously thinking about doing this, you need to read this whole forum. Most of the questions you ask are answered in previous pages.

1. Yep, the crossmember doesn't get that much force, and it's almost all shearing force, which the frame is very strong against.

2. Track is an inch or two wider in Lenko's cause he didn't cut the links.

3. N-Body bolt pattern is 5x115, so yeah, unless you do a n-body front swap you'll have the stock 5x100 on the front.

4. "the J-body ones are too small a hole.. way too small" - Lenko

5. Not even remotely close at all. We have a single bolt (like a shock). N-Body is more of a traditional front wheel strut that attached to the spindle with two large bolts.



Re: IRS How to
Wednesday, October 26, 2005 7:46 AM
Eliot, www.car-part.com will be your friend.







Re: IRS How to
Wednesday, October 26, 2005 8:33 AM
FstCavZ24 (Turbo ECO) wrote:

Eliot, www.car-part.com will be your friend.

That's where I find all my yard stuff since I found the site. Wonderful site.



Re: IRS How to
Wednesday, October 26, 2005 4:18 PM
Okay, but on 5 why not use the lower half of the n-body, and then bolt in the cavalier yellow. This would give you the best of both worlds, you can use the Upper mounts and springs of the cavalier, and they lower connection point on the n-body suspension.



Re: IRS How to
Wednesday, October 26, 2005 5:00 PM
The cavalier yellow for the rear is not an instert, it's the whole thing. You might be able to use the front yellow on the back. I'm not sure how the dimentions would work. I suggested using a AGX front on the rear (something like what you're proposing), but was told that wouldn't work. On the other hand, nobody gave me any good reasons why it wouldn't work. Something to look in to I guess.



Re: IRS How to
Wednesday, October 26, 2005 10:41 PM
as soon as I get some of these side jobs out of the way, I'm picking up the parts for this and the rest of the parts for the front brakes.......




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap

Re: IRS How to
Thursday, October 27, 2005 12:02 AM
The Konis for the SHO will fit into the stock dampeners in the rear of an N-body. I'm sure they would work in this ap. I have had them installed on an alero with great success. FYI. The cavalier front incerts fit the N. If there are any left out there. Use stock shocks to cut up....not KYB's. Really tight fit!!!

It will take me a while, but I should be able to find the Koni number.

Just to stir S$%^. I agree with the fellow who questioned the ultimate improvement with this swap.

Just look at the Cobalt GA racing program. I'd say it's sucessful. They even have a neat adjustable twisty beam. Sharp!!

As of yet, I can't recal a purpose built racecar in FWD. Other than factory cars made to race. But the it's not purpose built. Arguing that IRS is found on racecars doesn't fit this. IRS on a RWD car....a must for the twisties as far as I'm concerned.

I'll admit that IRS is good. And this swap combined with teh fact that you get rear discs is pretty cool. Albiet overated/marketed for street cars. It's just not the holy grail of the J body. I'd spend my time elsewhere. Maybe do this once I took care of everythig else.

IRS on front wheel drive is comphy indeed. A little more robust. What real benefits are there to be had. I guess the big one for me would be stability op high speed sweeping corners with irregular bumps. Most of my agresive driving is at much lower speeds. Mostly to keep me out of trouble. Most of my driving would not benefit from this. I wonder if an IRS will truely be all that better in autocross even? I guess fi I had the time and equipment, I would probably do it. I wouldn't trust any welder short of a NASA spec welder to take care of those links. Eh...not even NASA guys now that I think of it.

As far as trhe camber issue with compression on a twist axle. You can shim a J to give a better patch in corners. You just wear a little on the inside during normal driving. If you off set this with driving agresssively consistently...wear is not an issue because you are burning rubber of the outside.









Re: IRS How to
Thursday, October 27, 2005 12:17 AM
Ok.. drove the car for a little bit today.... and drove it home (30 minutes) tonight...

handling is good.... alignment needs work.... zero clearance issues... I may not even have to roll the fenders after all....

E-brake works WAY better than the J-body one ever did. Wow.... it's amazing.






Re: IRS How to
Thursday, October 27, 2005 5:21 AM
Go read Chassis Engineering and Competition Car Suspension

We pretty much know what we're talking about....



Re: IRS How to
Thursday, October 27, 2005 6:24 AM
Do either of those books refer to front wheel drive? Pretty sure not...however? I have not read through either. I'm betting there is very little on front wheel drive. And that is what we are talking about.

You could say I pretty much know what I'm talking about too. At least to the extent that I have commented.

You can at least acknowledge my points. I think I made some. These are not race cars. Never will be in the FWD format. At best a spirited street car.

I'm not saying this is a stupid thing to do. I'm not trashing the concept at all. Just saying like the other fellow that the swap will not make it a new car. Front wheel drive will never see the whole advantage of rear independent. The ox cart rear suspension follows along very happily indeed. Until you damage something. Then both sides collapse entirely. Huh. I'd have to say that that's it's biggest disadvantage.

For the price these guys have done it for...why not?

I will stick to my guns about my opinion. Same with rear discs on a street car/daily driver. They suck (at least in any snow belt)!!! 40% pad on the front of my Monte....rears are toast. All because of dirt.




Re: IRS How to
Thursday, October 27, 2005 6:54 AM
Pictures Lenko, pictures!!!!!! Lets see it sitting utside in the sun, from the front, side, and rear. that will allow us to compare with what McMoney did, thought I am liking yours as there is almost no modification. big question is how long did it take?



Re: IRS How to
Thursday, October 27, 2005 7:07 AM
What makes you think the front wheel drive is so very different from rear wheel drive, or four wheel drive, or more??

I'm not disputing that you have a bit of truth in your comments. But I think you sorely underestimate independant suspension. Let's take an opposite example once: A school bus, a rather extreme example of a non-racing vehicle, has beam front and rear suspension. They are stout, slow, and handle horribly. That horrible handling is not all because of the high center of gravity (although it hurts bad), much has to do with the suspension which is not made to react to the road.

You made the point that the largest advantage would be during high speed cornering over uneven terrain (yes roads are a type of terrain). This is mosly correct. I think you largely overestimate how smooth roads are though. Traction is really just static friction, which is largely dependant on the force between two objects. When your car is riding around any turn, hitting a "bump" of just 1/2" unevenly (one tire) would add a force of 100lb (or more) to that tire; coming off that bump (and assuming the suspension can immediately react) you have a sudden loss of 100lb of friction producing force at a tire. That can make the difference in control of the car at times. At the very least it will make some small differnece in how the car handles. 1/2" is not very much, and is totally acceptable on modern roads. (Figures reflect generaal calculations based on stock suspension)

Your happy-go-lucky gentle driver will not benefit from independant suspension. "Grandma" style drivers don't need independant suspension in the front. It doesn't benefit them in the least. So why don't we offer Cavaliers with no independant suspension at all? Because that is not the way most people drive. And some people like to push it "to the edge". Adding independant suspension to the rear of the vehicle extends that edge, making it harder to go over. And we all know the concequences of going over.

As for any points related to professional cars (such as Cobalt racing, or Sunfire racing in it's day): They have to stick with alot of stock features. Putting IRS in would disqualify them because it was not on the stock car. Putting a race modified Eco in a tubular front end doesn't disqualify them cause the car came with a Eco and Unibody font end. (If it doesn't difqualify them, it does put them in a different class).

Disks or drums in the winter... Well mine is a convertable, and I only drive it in the summer. Lenko's is a convertable too, although I don't know if he drives it in the winter. Most of the people doing this type of modification to their car's have other daily drivers, or "winter beaters". I do disagree with the rears wearing faster than the fronts, maybe your proportioning is off? YMMV.

I'm sorry if my posts come off as a bit harsh, it's my personality, nothing personal.



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