Speedtech IRS on 2nd Gen F-Body

[Urs]

Hello Guys,

Anyone here who has some experience with those IRS Setups from Speedtech? Traditional IRS and/or the cantilever Design?

Is it more a kludge or a really good alternative compared to the solid axle with torque arm?
Main target is Fun. Especially Autocross. A bit of mountain race and some road track days for fun too.

I do not want a big discussion if IRS or torque arm is generally better. There are enough of them. What I want to know is if this particular IRS from Speedtech for those 2nd Gen F-Bodies do work well especially for Auto-X. As well as if the car-design limits the advantages of a bolt-on IRS in a way that it does not make a lot of sense to use one and additional money would be +- wasted.

My personal intention is to go with a torque arm. I have no problems with solids and like the rough feeling, the ease of maintenance and the usually predictable limits. And it is also a historic thing. Old car old ideas.

But there is one thing: I'm (too?) often impressed by the suspension of my modern street-cars like the Audi RS4. Especially the one with cross coupled/connected dampers (Left front/right rear and vice verca). Possible corner speed is quite crazy for a ~2t family car. The combination of very limited body roll on hard cornering but quite comfortable ride on the straight over small bumps is pretty cool and very different to aftermarked products. Less comfort and normally more bodyroll or no comfort at all. I've tested aftermarked supsension because the parts do fail quite often (first series) but it is really never as cool as the original DRC.

So I thought about such a system to upgrade my fun car. But I'm not sure if it is worth to try it out if back and front suspension are of different type. And I'm not sure it is worth the effort if your are not an OEM because it is hard enough to find a good setup without coupling. And BTW I've never seen such dampers as an aftermarked pruduct. ;)

Thanks for some inputs!

[dontlifttoshift]

Is it more a kludge or a really good alternative compared to the solid axle with torque arm?

I do not want a big discussion if IRS or torque arm is generally better.

I don't understand the question. Honestly, I think you will be hard pressed to get an objective opinion in the SpeedTech IRS. The number of people who have paid retail for that suspension and can compare it to anything else is going to be small. Call Smitty and see what he says as I don't think anyone has more seat time with it than him. SpeedTech might have some references as well.


If you have any links to how the DRC actually works, that would be awesome. I know what it does but can't wrap my head around how. I do find it interesting that they tout is being all mechanical when it seems it would be easier to control it electrically and give the engineers far more inputs to make adjustments with.

[Urs]

Hi Donny, thanks...

Yeah I understand it will not be that easy to find people having the possibility to have tested both. But some information about the IRS would allready be fine. In simple words, is it worht on a car, especially the 2nd gen F-Body that was not made for IRS to bolt on an an IRS. (Heavy Front; necessary cut outs, limited possibillities --> too limitated to work nice?)


Well there is unfortunately not very much public material on the DRC. I've sarched many hous for it. Maybee someone working for Audi could offer some of the information which is not secret. Otherwise you would need revers-engineer the dampers. The pretty cool thing is the fact that it is fully mechanical. It reacts immediately.
In my opinion it works like a charm for a street car, but I have no idea if it works for race too. I think it could be quite hard to really change or fine tune settings but could be ok for a one for all setting for street/hobby race and you just play with the max pressure. In fact it is really cool for a daily car. It becomes hard if you push hard, otherwise it damps really nice. According to a friend of mine it has been used or is still used in some pro Rally series but I could not really find information about it.