james_marshall

My first quest for advice from you guys!
The rear anti roll bar is showing its age and needs replacing. The car is pretty much standard and is a road car only. The wheels are a little bigger but that's about the only change.
The change itself seems quite straightforward - I've been searching through the threads on here for days! But cant really find a the answer for my question!
Can someone guide me to a supplier where I can get hold of one for a '90 C4 and offer advice as to the best size... H&R seem to do kits for front and Rear but of sizes 24mm and 26mm respectively. Now from what I read on here and other sites(!) the 26mm seems a little much for the rear on a road car?

22mm seems to be the a good size for the rear but i can't find anywhere to buy one! As for any further suspension upgrades, I'm not ruling it out, but it's not on the immediate list....

So I know the question's been asked before.... But only seem to be related to the c2!

Any advice taken!
Cheers,
James.

Laker

Hi James,
I went with a 21mm Porsche bar on my C4. It came standard on the 1990 C2.
Here is my complete shopping list from Sunset Porsche (in USD):

964 333 701 07 (21mm Stabilizer-Sway Bar) - Qty 1 $149.50
477 411 313 D (Rubber Mounting 21mm) - Qty 2 $13.10 each
N-012-228-3. Qty 4 $0.23 each
900 075 099 02 (Hex-head bolt) - Qty 4 $0.52 each
900 082 035 02 (Hex-head bolt) - Qty 2 $2.47 each
999 084 445 01 (Lock nut) - Qty 2 $1.32 each
113 411 333 (Retaining bow) - Qty 2 $3.46 each

total $193.20 (plus shipping)


Do a RL search on "964-333-701-07" for some good reading.

alexjc4

If you have a 1990 C4, you probably have the 18mm rear ARB. I also had that ARB and swapped to the 21mm, it was noticeably better.

But put it this way, when I next get into taking my suspension apart, I'll go with the H&Rs I think.

Note that the thickness of the bar is not the only variable - some are adjustable and from different materials or even hollow, so bars of equal thickness can't always be compared.

I'm puzzled that people assume what will work for a C2 is automatically the correct thing for a C4 but as you say there's not much guidance out there specific for the C4.

kos11-12

Have you try TRG , I just looked and it's listed but you have to enter in 964 C2 ....

Pesty

I swapped to the 21mm and also used poly bushes on it at the same time. made a bit difference .

jackrobert

Thanks for sharing information .I would see all details.I can decide based on the maker .

anti roll bar

boxsey911

In the case of the bigger rear ARB I think many people change on the basis of the 'wringing out the C4 article' you can read here

https://rennlist.com/forums/964-foru...rrera-4-a.html

alexjc4

lol, yup it was on the basis of that article that I got mine

Goughary

I swapped mine for a C2 rear bar - very happy with it. Car handles much better. I have no idea of what bigger bars front and rear do to the handling since i never have had a different setup - but jst to chime in on the C2 bar in a C4 - this is a good way to go if you dont want to change both front and rear and want to stay inexpensive, since a used C2 bar should be relatively easy to find...

I have the original C4 18mm rear bar for anyone that wants to make an offer and pick it up...

Laker

I couldn't even give mine away, here on the 964 board or the RL Recycler Forum. ended up in the trash

FeralComprehension

If you're interested in looking at a low-budget alternative just replace the endlinks and mounting bushes on the rear bar and remove the front bar. The net change to balance is similar and it both costs and weighs less than adding a bigger rear bar.

I did this when I installed KWV3s and (so far, anyway...) I'm quite pleased. The additional stiffness of the V3 springs eliminated any additional roll that I'd get from having removed the front bar and I haven't lost any rear grip from a bigger bar. Keep in mind, that's what bigger rear bar does- it doesn't reduce understeer, it promotes oversteer, and it does so by lowering rear grip. Removing the front bar does reduce understeer, and does so by adding front grip. Adding grip is always better than lowering it

Note well, I've not had any track sessions with the revised setup. I have however had a number of (very positive ) slight oversteer experiences while exiting on-ramps WFO.

Give it a try; it's a cheap alternative....

peterC2S

Am interested in learning a bit more about this theory as am currently looking to refresh my suspension - either PSS10s or HD/H&R greens

When you say to replace the endlinks & bushes on the rear - with what? Or are you saying replace them with stock because they'll be worn?

And by removing the front bar, if its as simple as that why would Porsche have designed one in the first place. Plus, are there any views/experience as to how that would impact track/DE performance?

Both Steve W and Gert recommend the adjustable RS ARBs for C2 or C4 with either of the Bilstein coilover or shock/spring options - so I'm picking that there's some good experience behind that recommended combo. Keen to hear opinions if anyone is running that combo - specifically on a C4

GT9111

I recommend the RS rear swaybar. I've had it in my C4 for over ten years and it is effective in reducing understeer.

jack.pe

Just a theory... the chap who posted this theory said he had upgraded to stiffer springs.. the original cars work with softer springs and therefore need the front anti roll bar... presumably with stifer springs the need is not so pronounced. I also have stiffer springs and this idea really does appeal. Theoretically it should work. I might try it: 1. Cheap 2. Save weight 3. Might actually also improve the ride slightly on my car which is slightly too stiff.

jack.pe

Thanks, really interesting theory. Might just try it. Am slightly worried about high speed stability though... you've not had any snap overersteer moments i take it?