2nd Gen IRS

[srh3trinity]

I'd talked to him about this board and he knew all about it... I'll find out tonight if he's a member here. It will be a week or so before we're back in the shop and working on it again. He IS installing a full rect. tube chassis into the floor to lower the car, so the mounting points will all be on new metal; however, the Z subframe mounts line up exactly with the width of the stock rear subrails, just not high enough in the car...

I would love to see it. I have searched ebay for a 350z and IRS and the prices are pretty cheap. I haven't emailed to see what parts that it comes with though. What is he doing for brakes? Re-drilling the 350Z rotors?

[jp455]

I think definitively need to fabricate a new subchassis/frame rails to take full advantage of an IRS.

[silver69camaro]

Matt-I agree on a track both systems combined with our cars wouldn't be very different if at all. But driving on a bumpy road I bet the difference would be noticeable if the IRS is well tuned shock and spring wise.

I agree.

[Macadoo355]

Ill be a full frame, full cage "mild" street car. No drags or any of that dumb stuff just the twistys. I have some basic pictures of the first stage of measurements and cuts ill post up later. I think it'll be a cool ride as long as I don't screw up to bad. Ill try to get them up once I'm home.

http://s14.photobucket.com/albums/a3...o-%20Take%202/

[exwestracer]

I would love to see it. I have searched ebay for a 350z and IRS and the prices are pretty cheap. I haven't emailed to see what parts that it comes with though. What is he doing for brakes? Re-drilling the 350Z rotors?

I talked to my student about it tonight. He is a member and agreed to post pics up as the build unfolds.

[jp455]

Definitively look forward to seeing it!

[Macadoo355]

Let me know if that link works out or I can try to post the image on here.

[jp455]

Link doesn't work...it just takes me to the photobucket home page.

[rednecknate]

I can tell you a rear end not to run.. second gen rx7... I did an irs set up in a 94 toyota pick up years ago and while the handling was unbelivable... And 4:88's and a posi was cool I was constantly breaking third member's and Mount's With a 245 wide tire and a built 4 cyl.. Around 200 ft pounds of torque maybe.. But man it was cool...
MarkV Supra rear ends should be a valid option also . lots of guys making 1000 plus horse outta those twin turbo monsters... Big brake option etc and realative cheap .....Much more support then probrobly any other import IRS.. My 2 cents...

[jp455]

Yeah...I know many RX7 guys swap in a Mustang Cobra diff when they do the LS swaps. The thing with many of those IRS systems is that they are multi link arrangements with complex pick up points. A simple double A arm suspension I think would be easier to fab a subframe for.

[Macadoo355]

Should be making progress mid next week? More pics then.

[jp455]

Lovin this mixin and matchin. Really curious how it turns out.

[BrianP]

Although I have to say...the last scratch built car I worked on we did the uprights, A arms, etc etc...and it wasn't thaatt bad cost wise.

JP455,
What kind of spindle setup is this?

As far as the Heidts IRS: it's design looks pretty outdated. If you break a half shaft.... your crashing since the half shaft is used as a suspension member.

[jp455]

Thats a spindle we designed and CNCd from scratch for a supercar project I worked on. Theres more info in a thread I started called New Car. Its a cool piece cause only one model works for all corners of the car. It is a bit heavy, but its made for a road car where durability is key. Plus it had to stand the forces from the huge carbon brake discs. I forget the size right now, but they were either 14 or 15 inches but for reference thats a 20 inch wheel its in!

Yeah I know what you mean about the half shaft. That and the limited brake caliper applications.Thats why I mentioned that its outdated technology. But I'm still curious as to how it rides/handles since right now its the only bolt in system out there.

[BMR Tech]

Just something else to throw out there: The new GTO rears are not a double A-arm setup but they work really well, are very well packaged, and you can buy the whole setup brake-to-brake all day long for $250 on Ebay. You have very limited gear selection and posi units but they come with 3:45 gears and posi-traction from the factory designed to work in a 400 horse, 3800 lb. car so they do hold up fairly well. If you make more power we (and other companies) offer billet 300M CV shafts and stubs and there is even a company now making Ford 8.8" retrofit diff kits. For $250, you could buy a couple of spares!

[exwestracer]

Update on the 350Z rear install:
We put our heads together last night on how to best mount the Z subframe under the Camaro. Ryan (Macadoo355) made what I believe is the right decision in doing minimal cutting and using as much of the stock sheetmetal as possible. At this point the plan is to build a 2X3 "frame" from the front bumper all the way to the rear mounts for the Z suspension. This will be welded into the floor just as you would install subframe connectors, making a very strong unitized construction. At the rear, a crossmember will be installed between the stock subrails where the new frame ends. The new frame will incorporate mounts for Camaro type aftermarket front suspension and the geometry will be corrected along the way. Hopefully Ryan will keep posting pictures as the project progresses. He might move this build to the projects thread, but I'll make sure to post updates on the Z suspension installation here.

[jp455]

What I'm most curious about this install, and other that mix and match front and rear suspensions, is how much harmony the whole system will have when it works together.

[Stage4 Performance]

Very interesting stuff...
Subscribed!

[exwestracer]

What I'm most curious about this install, and other that mix and match front and rear suspensions, is how much harmony the whole system will have when it works together.

Actually it should work quite well with the changes we have planned at the front. We are trying to achieve a common roll center movement front and rear under roll compression. This should give the car a better "feel" for the driver, as both ends will be doing pretty much the same thing as the lateral forces go up.

Great theory, anyway...

The cutting is almost finished. Hopefully, we will be laying out the new rails tonight.

[jp455]

So does that mean you're going with a custom front end? It would be a huge coincidence if those geometries lines up with something that's already out there! I asked Detroit Speed for their front end geometry once to design an IRS, but they said no. Completely understandable, but it would have been cool to design something complimentary.