Rick964

I have a 90C4 Cab and am looking to lower the car to improve handling. I autox now and am planning to do a few DE's or time trials. I don't plan to change the shocks at this time. So is there any benefit to either Eibach or H&R over the other?

joey bagadonuts

Please change the shocks, too. I just switched to the Eibach Pro-Kit (which I love) but I left the Boge's in place. I could shoot myself!

I was a little concerned about the affect new springs and shocks might have on my ride quality, but the Eibachs actually gave me BETTER ride than the stock springs. The rear end squat was dramatically reduced and I no longer felt a jolt every time I hit a pothole. Now I want new shocks which will cost more to install now than if I had switched them along with the springs. Learn from my mistake.

I can't say if one brand is better than the other, but the ride height can be fine-tuned by your shop using the spring perches, so don't let that drive your decision. My springs actually lowered the front 2" and the rear by 1". My car is pictured in a relatively recent post entitled "Just lowered with Eibachs." Someone else might be able to speak to the differences between H&R and Eibach. And make sure you get a corner balancing and RS alignment before your car leaves the shop.

Drew_K

There's a local Porsche shop that specializes in race prepping Porsches, although they do routine maintenance as well. I've spoken with the owner a few times about suspension upgrades and, in his opinion, Eibachs are better than H&R's. He was pretty critical of H&R for various reasons.

For a street/autocross car it may not make much of a difference though.

Jeff Curtis

I did quite a bit of research on this EXACT topic before I upgraded my 964.

The H&R sport/lowering springs are progressive, meaning that they provide more resistance the more they are compressed. This is for ride quality on the road, while providing an ideal amount of stiffness under load, while on a "spirited" drive, at an autocross or track event.

The Eibach springs are NOT progressive, they come on stiff, almost immediately.

I feel the need to tell you that I attend 10-12 track events a year, I have Bilstein HD shocks with H&R sport/lowering springs for a 965 (964 Turbo), which provide approximately 35lbs more a corner when compared to the 964 sport/lowering springs.

My car handles like a dream on track, and isn't too uncomfortable or "jolty" on the street. I feel my car is very competitive on track, and seems to be one of the more dominant cars at any motorsports event...but then that's me.

...I'm not talking about in the GREEN group either!

My opinion would be to go with the H&R progressive rate sport/lowering springs, and I like the Bilstein HD shocks too, several have gone with Koni adjustables...which are a great idea, but a bit pricey compared to the pricing on the Bilsteins.

Checkout <a href="http://www.shox.com" target="_blank">www.shox.com</a> and ask for a price quote, they'll get back to you fairly quickly.

You can also view a full procedure, with pictures on <a href="http://www.porsche964.co.uk" target="_blank">www.porsche964.co.uk</a> - there is an article written by me, another written by Bill Gregory and friend. (forgot his name) <img src="confused.gif" border="0">

jonfkaminsky

There is complete H&R/Bilstein "kit" for the Porsche 964 on E-bay at the moment. You might be able to "buy it now" provided the parts are correct. There are differences in the rear setup due to spring strut dome changes in MY1991, so the set could actually not be appropriate for your car.

Adrian has the complete details- I just have enough to know that my MY1991 has the old strut domes.

malc elliott

I have just fitted Eibachs (see FVD ref 333 964 00) on my 1990 C2 Cab and am extremely happy with the results. As Joey says,there is a distinct improvement in the ride over potholes. I didn't change the shocks, however I don't regret it at all. That said,I don't autoX.
I must disagree with Jeff here, for the Eibachs I have most certainly ARE progressive. It was for this reason I purchased them and they haven't disappointed.

Adrian

Dear Rick,
I will provide a totally objective answer (I think not). I have driven my own C4 EIBACH (RS) Springs and KONI Adjustables and I have driven C4s and C2s with the H&R/Bilstein set up and just H&R springs and I just recently drove a K&W Suspension system set up C4. Personally I will stick to my EIBACH/KONI. The main thing is that the KONIs are a adjustable and with practice you can change the settings to suit your surroundings.
I do not like the H&R Greens. THe H&R race set up is very nice though as long as you drive on a smooth surface or wear a mouth guard,
Ciao,
Adrian
911C4

MikeF

I've had H&R progressives on my C2 cab for about a year now, with original Boge shocks. Initially I thought the ride was not firm enough. Although H&R claims that there is no "break-in" period, I must say that the ride and handling are now beyond my expecations. Comfortable and smooth around town, and flat and confident in the twisties. Lowered my car about 1" - exactly what I wanted since I still need to clear driveway entrances, etc.

I bought my H&R's from TireRack for $314. Highly recommended based on my humble experience.

Bill Gregory

You may want to also consider the Porsche Carrera RS suspension, which is what I installed, and along with Tom Masino, who installed it on his 1990 C2, wrote the article Jeff referenced on John Miles web site.

The RS suspension consists of springs/struts/shocks/sway bars and other pieces, and are competitively priced (you can get them at upwards of 30% discount). They use progressive springs which, as Jeff mentioned, are a compromise for dual street/track usage. It sounds like progressive springs are what you'd want to use on your multi-purpose C4. Keep in mind that Porsche changed the rear suspension geometry in 1991 when you look for new suspension parts (irregardless of vendor). When Tom installed the RS suspension on his 1990 C2, he had to do some fabrication to get the 1992 parts to fit his 1990 C2 (pictures are in the article).

Since you have a Cabriolet, you probably know that you'll likely need to install a rollbar before taking it on the track. Check the rules for the organization you'll go on the track with. One solution, which I have, is the DAS rollbar. It's a pricey option which bolts in and doesn't require welding (although you may have to drill some holes for the cabriolet version).

Oh, and to reiterate what others said, you really ought to upgrade springs and shocks at the same time, as they work together.

cbottone

Rick,

I bought my 'stock' '93 C4 for dual street/track use having read about about the US version's excessive understeering tendencies. My first time with it out on the track though, I was still unprepared for how much it terminaly understeered. I was very disappointed with the handling and felt like the understeering was crippling its otherwise impressive performance capabilities. I hadn't noticed it on the street or mountain twisties since i never pushed the car's capabilities like on a track.

I sought help and guidance from one of the best Porsche race prep shops on the West Coast. They had done many suspension conversions of both Eibach/Koni and H&R/Bilstein type (+ larger rear anti-sway bar) and had settled on the H&R/Bilstein/swaybar as their recommended solution as they felt it performed slightly better on the track but also drove a little better on the street.

I went the H&R/Bilstein route and I highly recommend it. The car's track handling improved 1000 pct like night and day difference. It feels only slightly stiffer on the street and I can easily live with it.

I have since also driven a friend's car on the track with Eibach/Koni modification and it too feels good. Frankly it feels and looks the same as mine. If anything maybe it felt a little stiffer over potholes at low speed in the paddock but I haven't driven it on the street so i can't really judge street ride. For the track i'd say they felt equivalent, but maybe i'm not as discerning as my race prep shop.

The one thing I would most recommend is that you go with both spring and shock together, they are made to work together.

cbottone

BTW there is a nice 2 part article analyzing std and sport supensions (US & RoW) with a 996 in the last two issues of Panorama (PCA club zine). They also use data on H&R and Weltmeister in their comparo charts.

Made me glad I went with H&R/Bilstein vs Porsche Sport suspension upgrade.

Bill Gregory

[quote]<strong>Made me glad I went with H&R/Bilstein vs Porsche Sport suspension upgrade.</strong><hr></blockquote>

Do you mean the M030 suspension option for 964's when you say Porsche sport suspension upgrade? That upgrade consisted of a stiffer front sway bar, the stiffer Turbo progressive rear springs, and the firmer Turbo rear shock absorbers. Or do you mean the Carrera RS option? or Cup equivalence? Just curious. I read the Pano articles also, and while a very good piece of work, I wouldn't assume the values and analysis hold an exact parallel to our 964 suspension options.

cbottone

The articles referred to the M030 sport option which apparently is different for US and RoW.

Bill, when you refer to RS option is that the European RS only or also the US RS America. I was under the impression that the RS America just had the M030 sport option.

MelissaM

I have had the H&R Springs on my '90 C2 Cab (with the standard shocks) for 3 and a half years. I do a few autocrosses per year, and have a little fun on the street. I must say that I'm thrilled with the springs -- probably the best mod I've made on the car. It has cleaned up the fender gap and improved handling without sacrificing ride quality.

I'm guessing that for the "average" Porsche driver, the Eibachs or H&R's are a fine choice.

I should also mention that I got my H&R Springs from Windward Performance, and the whole business transaction went as smooth as silk. I know Windward has gotten a bad rap on these boards in the past, but they did fine by me. Dan of Windward helped me select the springs -- I'd originally wanted the Porsche Euro springs, but they didn't have them for my model year.

-- Melissa

Bill Gregory

[quote]<strong>when you refer to RS option is that the European RS only or also the US RS America. I was under the impression that the RS America just had the M030 sport option.</strong><hr></blockquote>

Correct - The RS America had the M030 option. The Carrera RS suspension is what was on the 1992 964 Carrera RS, which was a limited run model, not available in the US.