Jim,

Could you share your thoughts on the revalve for the GTWorx springs? Do you have the datasheets like fireroasted?

Thanks

 

I don't have the datasheets, didn't know that Bilstein offered them at the time I sent my set in for a revalve


With the revalved Bilsteins and GTWorx springs, the car is definitely more capable than my old setup with OEM KYBs and GTWorx springs. I DD/auto-x the car (15-20 events a year) and it doesn't miss a beat. Ride quality is better than the KYBs over smooth-ish roads, but feels the same or worse over broken pavement. Without a chart in hand, it feels like there's too much rebound and not enough compression, a common complaint about Bilstein revalves I've heard.

Keep in mind my impressions were formed without ever riding in a stock MR Bilstein Evo lol

 

Those comments are inline with where I have been on the revalving. I did several years on stock bilsteins, and then stock springs on revalved bilsteins. I would agree with impressions about too much rebound and not enough compression. However I am not a suspension guru. I have a set of stockers now and am now running a set of revolved (the charts mentioned) and the robispec springs. Its very capable now, but is right on the edge for me as a DD. I do daily the car though I don't commute with it.

If I had to narrow to one issue, I wish there was a vendor for the revalving or a how on how to maintainance them yourself. I bought a harbor freight spring compressor and I can change the springs in 5 minutes now. But if you do ask for the revalve it would be safe to ask for less rebound on the rears than they tend to put in. It kind of slams over reflectors, and I am not sure that is ultimately that beneficial on track for the vioence it produces in the cabin.

 

great combo!

 

Fireroasted, my shocks are now with Bilstein and I have the same Robispec/OE Bilstein combo. I looked at your other thread but could not really make out the complexities of the charts. I spoke with a Juan@Bilstein today, and he suggested I get in touch with you as it sounded like there was a lot of back and forth for your particular case.

It sounds like the general conclusion was to give them the approximate numbers of the springs: 240 lb/in F, and ~280 lb/in R.

How do you feel the increased low speed damping and reduced high speed damping has worked out for you? Is that something you specifically asked for? I feel the balance in turns and general around town driving is great - but dealing with light markers and potholes is an absolute nightmare. I'm guessing that's part of the reason for reduced high speed compression?

Also, did you ask for reduced rebound as well (fronts, rears, or both?) I'm just trying to an idea of how these changes will affect the driving experience compared to the stock valving values of the Bilsteins, and whether or not that's something that's worked out for you. Any info would be much appreciated - I dislike this "black box" feel as you mentioned, and I would love to make some sense out of these numbers.

 

The complaints about too much harshness from square edge bumps, and not enough compression don't really jive. It's HSC that makes the square edges feel sharp. LSC can have a hand in it, as well as the position of the knee, but those are mostly chassis motion like leaning and braking.

Jim / FR, how does the rebound feel too slow? Is it ride quality harshness or is the car slow to take a set in turns and recover from dips? Do you feel like it's packing?

I've got the GTWorx/HD's and it feels to me like I could reduce HSC for better NVH, but need a bunch more LSR/HSR to match the increased spring rate. Going over undulating and broken pavement at low speeds gets the car to rock and roll like a bathtub full of water. Real high speed transitions on the track are a bit quick for me too.

Curiously, are all you guys running stock bump stops?

FR - Is this the spring compressor you have?
http://www.harborfreight.com/automot...sor-43753.html

 

OK, I wish I had better information for you at this time, but since my suspension projects I ran into a bunch of mechanical issues, that I still am not done with, so the car hasn't seen any track time on the new setup. That setup includes the Robi Springs and new valving. So I can only give street driven comments until I get on track.

I did work with Juan. My first tip is to ask them to install the extra large bearings. Something about being the same as the 911 porsche bearings, as they are much larger and can handle bigger side loads. Call him tomorrow if you can.

The settings was tough, because I could never talk to the person actually doing the work, and that was pretty frustrating. Everything was a go between, and without wanting to sound rude or disrespectful, lets just say it was tough for me to get what I was after with the go between mechanism. I was always hoping a smaller shop would do this work that I could chose. Someone you can call and discuss you vehicle and desires with. It is very specialty stuff, and its not cheap. But, considering all that the comments made above are solid. I feel there is too much high speed. And in case I don't get it properly then let me say there is too much of whatever makes reflectors feel like you have no suspension at all. Not sure why they go for so much. I had a bunch taken out the second custom valving and it is still too much.

As I said before I wonder if the stock valving and Robi's is the best choice. I will know is a few months as I have a set of each, but currently I haven't been on track, so more on that later.

If I had to give another comment on street manners is that at certain pavements imperfections that repeat in rythym its seems there is too much teetering. front and back, and you kind of feel like that jackhole that lowered his civic onto the bump stops in 86. (By the way I was the jackhole in the pickup with the inverted leaf springs 86)

 

I think the square edge comment is just to identify which mechanism is responsible for reflectors becoming such a violent encounter. I suspect its too much HSC, which matches your next comment. The comment about matching the rebound to the new springs is on target, but both compression and rebound need to be matched to the new springs, which is why i found getting the custom valving so frustrating. I was expecting folks were only going to have relatively specific valving for whatever springs I was brining them. But, unfortunately that is not the case, and reminds me of posts on this topic here, where the guru's are reminding the rest that Robi and others were designed with the stock valving in mind (and in math). So there you really need a shop that will taylor to your new springs.

I don't know if the rebound is too slow, or if its packing. In daily driving at least I can't tell. It doesn't feel like its squatting and staying there, if that is the same as packing.

The bathtub full of water is exactly what I was getting at in the above post by my teetering comment. The car may look terribly setup from even a mile away, and just down right annoying in the cab for those conditions.

I am still on the stock bump stops, and am really curious if I should modify that. I could never find that info, but I can correct for that really easily, which brings me to your next question. I use
http://www.harborfreight.com/1-ton-a...sor-65549.html
I gave up on the manual ones after several of them eventually stripped. That thing was on one of those coupons for 150 bucks once, and it works awesome. It does take up a small footprint though.

 

I wouldn't say the rebound is too slow, in fact it feels kind of fast. It definitely affects ride quality harshness, the valving gives the car a jarring ride over broken pavement, as it seems the car recovers too quickly after dips and such; in auto-x, the car isn't slow at all to take a set in turns. It also takes transitions well.

I'm also using the stock bumpstops and Ralliart top mounts. No difference in ride quality between OEM and Ralliart mounts IMO.

 

FWIW, I had slightly less NVH from road divider dots, especially in the rear switching from stock MR to Robispec/stock Bilstein. Also definitely less crashing through bad potholes than stock suspension. Slight increase in NVH from road divider dots after installation of the PSRS but within reason. I think that NVH is more related to the ralliart top hats and pillowball bushings than shocks.

All in all for road use I cannot see why anyone would want to change shock rates with Robispec springs - they seem perfectly matched as far as I can see. Track use may be a slightly different matter. Many people do not like the slight initial float of the Bilsteins on the track. More of a nose in initial damping as shown on the graph posted by Fireroasted will take care of that. Fair enough. I would say I appreciate the the stock Bilstein compliance for road use.

I use stock bump stops and see no reason to cut them with the 1" drop of the Robispecs. If anything they may save me from having a blown strut someday.

Would still be curious what the revalve that GTWorx does on the Bilsteins really is. Also would be curious to have a ride in the GTWorx/Bilstein combo. GTWorx have a little bit less drop than the Robispec and I believe have a little bit less spring rate but more rake. Personally, having the Robispecs I can see the wisdom of slightly less drop - I scrape my zero lift lip all the time - but I cannot see the need for less spring rate the way the Robispecs work, nor would I like the increased rake for how my car is set up.