Foxxtron

iTrader: (1)

1. I've not only owned 7 4th Gen F-bodies, but also have cut apart at least 17 other F-bodies, then analysed them through FEM. I've also fabricated several years before I eventually went on to becoming a Materials Engineer.

2. The very few who do know what they want performance wise would like to see an IRS for the 4th Gen F-body that:

a) exceeds the performance and reliability of the Fays2 Watts link. Lap/Track times should be the ultimate test to verify this.
b) can at least have an MSRP for something at least less than the value of the most well preserved 4th Gen F-bodies out there.
c) is easy to retrofit with little or no modification to the monocoque, therefore will not introduce structural integrity issues for the vehicle with or without even further expense or the possibility of writing off the vehicle.

AFA custom work for the sake of driveway jewelry, that's been done already. What's next?

Also, bear in mind that almost all major auto manufacturers with decent engineering do "AX, drag race, and open-track" their prototypes. Like Sam and MLS could possibly agree a suspension is more about how effective it works and less about whether it's an AX, RR, or a drag race per se.

AFA a "practical F-body" goes, they actually do have quite a bit of practicality to them. Heck, there were enough times that I was able to use the interior space quite effectively than most "non station-wagon sedans."

I do believe that what I post is more objective and less subjective.

will01

Thank you Foxxtron, have you experienced any reliability issues with the Fays2 Watts Link?

Foxxtron

iTrader: (1)

I actually have yet to try any of Fays2 Watts, but I have custom fabbed other designs that are similar. I can tell by it's appearance that it should be plenty stout, and for those who've tried it know already it's quality first hand. The points to where the Watts frame mounts are actually strong enough as well.

To also reiterate, I DO welcome to see an IRS that can work significantly better, not just marginally better than the Fays2 Watts. I'm sure a lot could use a design that can not only allow better control over rear camber and toe, but also one that can readily provide much better overall quality with regards rear end control and can at least not add more unsprung weight than a Fays2 does (which according to Sam Strano only adds ~11lbs.). It would also help if the IRS can eliminate much of the wheel hop issues.

IT_SS

iTrader: (5)

here's the link to the shop that did the car

http://zeuscatalog.com/jay_cutshaw_s_irs_swap

this looks promising....

Foxxtron

iTrader: (1)

Looks promising, however I'd still like to know more about it, such as:

a) track/lap times: What would they be overall for this vs. a Fays2 Watts link?
b) price: these C4 Dana44 rear ends aren't cheap either in price nor quality per se. Labourwise, it appears quite intensive, so I imagine that the overall price will be quite high.
c) body modification: Whilst I'm not able to see all through the website, on some pictures I do notice there's some cutting to the body in some critical places. What are their experiences with this type of re-engineering?
b) has there been a comprehensively proven shock, spring, and swaybar combination run with this setup?

Again, it's possible to improve upon a Watts link, but at what costs?

My reasons for posting are not to stifle one technology over the other, but to get as many answers possible from this C4 setup. No doubt that the C4 design has been retrofitted to many older vehicles with lower box frame designs through simple bracket attachment welding and little invasive cutting, however the F-body is a monocoque and whilst monocoques aren't necessarily weak per se, any type of cutting modifications need to be insured that they're not weakening the rear overall body stiffness.

IT_SS

iTrader: (5)

Is there a reason why it seems the C4 is the IRS of choice? What about the C5 and the GTO? I would imagine that they would be ideal given their year of production....Personally, I feel the IRS is the 4th Gen FBody's missing link. Include IRS, and you have a C5 with a back seat and T-Tops. Our cars are the most hated/loved in the performance car world and IRS would be one more reason for the 4th Gen to be loved/hated even more. Simply telling a person to go get a GTO/Vette is like saying a Camaro/Firebird that ceased production in 2002 isn't good enough.

slow

iTrader: (7)

If you look at a C5, the brackerery for the IRS is based around the frame, as well as using a rear mounted transaxle, solid mounted torque tube. and is not more like the C4's where it is more of a unit, the GTO IRS can be found for cheap, and I believe (I need to go under my car and look again, it's been 2 years since I really looked at the IRS design) it seems to tie into the body in several spots, and didn't appear to be a bolt in design, well, at least without building a support cradle.

The 2003-4 cobra design, is very interesting, and SVT was given a task to design this, allowing to to not require changes to the unibody. The result is a compromise, due to this requirement. It makes the setup somewhat valuable, for conversions, since it will bolt into millions of 79-2004 mustangs in the world.

Ryan

Abdullah

iTrader: (2)

looks nice, i'm interested in such an IRS to install in my camaro.

btw, is the IRS in the pic for a C4 vette?

01turdbird

There is the saying different isnt always better.
I have never understood this feeling. To me changing things on my car that provide no benifits to the driving or looks of a car but doing it just because it is different is weird. I mean I have never seen anyone take a LS1 out of a fourth gen and put in a 4 cylinder but it would be different right. So what do yo think should I go for it.

lees02WS6

iTrader: (5)

"I have never understood this feeling." "To me"

I rest my case your honor

00 Trans Ram

iTrader: (5)

About the ONLY reason you'd want a C4 IRS in your car is for show. Does no one remember the horrible handling that C4s had? Remember all those articles back in late 1996-early 1997 about how the C5 was light-years better than the C4?

In fact, I raced head-to-head with no fewer than 3 C4 Vettes this year. All of them had more power. All of them had bigger/fresher tires. All of them had bigger brakes. I could out-corner all of them.

Someone earlier said that not all IRSs are good. That's a fact. In fact, very few work well. RX-7 and C5 Corvette are 2 of them. C4 and Mustang are not. I'd put my live axle up against almost any IRS any day.

As for "most top-end cars have IRS", well that's true. Of course, they also have pro-drivers, crews, garages, factory/team support, test days, and no need to compromise. If those are the criteria, then it's EASY to make an IRS that is superb.

ThoR294

iTrader: (6)

Solid axle all the way. Pretty sure IRS is illegal at certain drag strips when you pass a certain time, no?

squee

iTrader: (16)

Thats VERY true. I drove my friends 04 Termi not to long ago and the IRS has got to be the worst in the world. It had terrible wheelhop, it wandered at high speeds (70+ and at 130 its almost impossible to keep in a straight line), and when it gets loose, its very unpredictable. Only positive is just cruising, it had a better ride than alot of cars. Also someone said earlier that a IRS will hook better on the street...I think not. Her car only had a exhaust and intake and couldn't hook for ****. Not even in 4th, and those cars aren't that powerful to be honest.

Abdullah

iTrader: (2)

so i just can go with Watts link and that's it for my 2000 LS1 camaro? is it realy not easy to fit the C5 IRS in my 2000 LS1 camaro?

Foxxtron

iTrader: (1)

As of this moment, the Fays2 Watts link is about the only thing on the market with a proven application to improving performance for the 4th Gen Camaro in that area of the rear suspension (the PHB area).

Well, what one could consider easy can be subjective. All I know is that if one were to take on that task, they should have a good structural engineering background (college or trade skill knowledge), many months of labour hours, precise tooling, several thousand dollars USD, and then good testing to ensure reliability, longevity, and most important of all...a substantial and highly consistent performance increase. If it's just marginal, then it's going to be a whole lot of sunk costs.

AFA the C4 IRS, it appears to be a sort of swing axle type, which is a design that's almost always worse than a trailing arm type SRA. I've driven many vehicles with swing axle designs (including C4's) and AFA I'm concerned, I avoid them like the plague.

lees02WS6

iTrader: (5)

It's not a swing axle type, its an sla with the half shafts acting as upper a-arms. Swing axles are rare, and don't have u joints at the hub, you could find them on old merc's from the 60's, and of course the early corvairs.

You could use a C5 IRS with out the trans axle, and a torque tube. There is at least one company I know of who makes a yoke, pinion, and cover for the C5 diff, that allows you to run the transmission of your choice and a normal driveshaft.

Abdullah

iTrader: (2)

you mean i can use C5 IRS in my 2000 LS1 camaro?

what is the website of that company if so?

lees02WS6

iTrader: (5)

With adequate fabrication skills on your part or someone else I'm sure it's possible. A possible problem would be the track length. I'll pm you the company, as I'm probably not supposed to post it.

00 Trans Ram

iTrader: (5)

I'm of the opinion that, unless someone is paying you to race, you won't be able to take advantage of an IRS transplant over a well set up stock design. Yeah, the C5 IRS "might" be better if the rest of the car is set up perfectly, and you (as the driver) is able to drive at 10/10ths 100% of the time. But, if you are inconsistent as a driver, or the car is suboptimal, then a well set up live axle will beat it.

For proof, check out NASCAR (live axle) vs Speed World Challenge GT1 (IRS). Jamie McMurray ran a 1:15.0 at Infineon Raceway in April 2004. The best times that the GT1 guys could muster in June 2006 was a 1:19.650. Sure, it's not exactly apples-to-apples, but it shows that a live axle isn't exactly a boat anchor.

Foxxtron

iTrader: (1)

According to the forum rules, you can name the company in your post, but you must not post the link.

AFA the C4 suspension, even though it's a somewhere between a SLA and a swing arm, some of the "swing arm behaviours" are very well present. I've owned 3 C4's from the mid-90's as well. The half-shaft CANNOT completely compensate for true upper wishbone control arms. If this was the case, there probably wouldn't be a need to have a complete SLA in the C5, however with that stated there are much more significant design improvements that contribute considerably to the C5's performance.

Nevertheless, I still want to see "real-world" application of a C4, C5, or maybe a C6 IRS retrofit compared to the Fays2 Watts. I do welcome it, but even with a 50% unspung weight savings and significant control over toe and camber, lap times will ultimately tell the truth.

With that stated, I've witnessed lots of what 00 TransAm has mentioned.