Bilstein HD / GTWorx -> Ohlins or AST?
I went with zero offset, so modification isn't necessary. I did it for stiffness.
http://perrinperformance.com/attachment/74806-.pdf
Evolved Member
Joined: Feb 2010
Posts: 1,630
Likes: 4
From: Columbia, MD
9k/11k on street tires for the time being. Looking into r-comps once I get used to the new set-up this season.
KW V3s
Polyurethane bushings all around
Perrin PSRS
F/R sway bars - Tanabe 25.4mm (F)/Progress 25mm (R)
F/R Perrin end links
Cusco Front Sway Bar Adjustment Bracket
Going to have to re-learn the car this year.
KW V3s
Polyurethane bushings all around
Perrin PSRS
F/R sway bars - Tanabe 25.4mm (F)/Progress 25mm (R)
F/R Perrin end links
Cusco Front Sway Bar Adjustment Bracket
Going to have to re-learn the car this year.
Ahh gotcha. Yeah from talking with some folks on here here it appears that depending on how its set up spacer wise, I may or may not have to trim the subframe...
Its strange becuase when you read those install notes it mentions using the medium on the bottom and then the large on top. But if you want anti-lift the small spacer is also used...ugh I was hoping you'd be in the know how but you fail me
Its strange becuase when you read those install notes it mentions using the medium on the bottom and then the large on top. But if you want anti-lift the small spacer is also used...ugh I was hoping you'd be in the know how but you fail me
Thread Starter
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Joined: Jun 2012
Posts: 402
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From: Santa Barbara, CA
Re:PSRS I'm running the offset units, spacers on top, and only had to bend the sheetmetal splash guard that "protects" the bushing down a little so the control arm didn't tap it. I get the slightest amount of contact between the arm and subframe, but haven't done anything to mitigate it as it really doesn't seem like an issue. The PSRS does have a significant effect on NVH specifically when hitting Botts Dots, very noisy, FYI. It also seems to really bind up the front inner control arm bushing. Going to a urethane replacement isn't going to help there, you'd need to use Robi's spherical to free it up.
Back OT:
Called Ohlins USA and had a good talk. Very friendly people.
- They think their specified spring rate (F10k/R8k) is a great compromise for R&T. They do acknowledge that many people change rates and they're good with that. I didn't talk with the development engineer for the kit, so that's about where it ended.
- They don't do custom valving straight away. You'd need to pay for a re-valve and springs on top of the kit. It sounded like the kits are made in small batches in Sweden, therefore would need to be serviced in the states upon arrival. Currently 15 sets are due in toward the end of the month, most of which are already spoken for.
- The damping adjustment has a +30-35% range over std springs. This should cover 10k rates in back fine, but 12k's would be getting fast & loose. The single adjuster has approximately a 33% influence on low speed compression, and a 66% influence on low speed rebound. It's basically a needle on the bleed circuit. The adjuster shaft is allegedly athermalized to maintain performance over temp so as to compensate for viscosity changes.
- They're proud of the compliance offered by the dual flow valve. It's a blow-off that keeps the shock from spiking on square edge hits, and allows for firmer low speed valving to improve handling.
- Torrington bearings aren't used in the spring seat. For street applications they feel the maintenance isn't worth the potential performance gain. Few of the professional race teams this fellow supports use them as they've not found any improvement.
Called Performance Shock in CA:
- Also very nice people to talk to. West Coast distributor and service center for Ohlins.
- Suggested just getting the kit and trying it out with provided springs.
- Acknowledged many if not most change springs, F8K/R10K, 10/10, 10/12...
- Said shocks should be okay 10/10, maybe 10/12 but toward the limit.
- Don't advertise but are willing to revalve new Ohlins dampers to suit specified springs for no additional charge, if purchased from them. It's a value they offer to differentiate from other mail-order shops.
- They see very few Ohlins R&T kits coming in for service which makes them think the product is well built and reliable.
Called AST-USA, kinda (972.424.3700). Can't remember the shop name, but they used to be AST-USA till the contract expired. Still dealing with the product though.
- Again, very nice folks who spent plenty of time on the phone.
- Asking what they offer for a street / HPDE application led to their 5100 of which they had a set built sitting in Holland a customer backed out of. $2600 w/o springs or top hats.
- When asked to compare to Ohlins R&T, they said it's really kind of a draw at that price level between the top shelf vendors. I mentioned the Ohlins come complete with springs, hats, etc and it was suggested that it'd be a better buy. He recounted a number of recent builds for domestic shops, the specifications and cost for reference.
- On the DFV thing, it was his opinion that the AST's likely could be valved to have the same performance but it'd take some work to get the same result. Ohlins is more of an out the door package.
In the end I ordered the R&T's from a shop here in town who sell both Ohlins and AST. He gave me a good break off list and worked some other stuff in too. Pretty sure I'll be stoked on 8/10 or 10/10 rates to balance street civility with roll control on track.
Thanks to all for the insight.
Back OT:
Called Ohlins USA and had a good talk. Very friendly people.
- They think their specified spring rate (F10k/R8k) is a great compromise for R&T. They do acknowledge that many people change rates and they're good with that. I didn't talk with the development engineer for the kit, so that's about where it ended.
- They don't do custom valving straight away. You'd need to pay for a re-valve and springs on top of the kit. It sounded like the kits are made in small batches in Sweden, therefore would need to be serviced in the states upon arrival. Currently 15 sets are due in toward the end of the month, most of which are already spoken for.
- The damping adjustment has a +30-35% range over std springs. This should cover 10k rates in back fine, but 12k's would be getting fast & loose. The single adjuster has approximately a 33% influence on low speed compression, and a 66% influence on low speed rebound. It's basically a needle on the bleed circuit. The adjuster shaft is allegedly athermalized to maintain performance over temp so as to compensate for viscosity changes.
- They're proud of the compliance offered by the dual flow valve. It's a blow-off that keeps the shock from spiking on square edge hits, and allows for firmer low speed valving to improve handling.
- Torrington bearings aren't used in the spring seat. For street applications they feel the maintenance isn't worth the potential performance gain. Few of the professional race teams this fellow supports use them as they've not found any improvement.
Called Performance Shock in CA:
- Also very nice people to talk to. West Coast distributor and service center for Ohlins.
- Suggested just getting the kit and trying it out with provided springs.
- Acknowledged many if not most change springs, F8K/R10K, 10/10, 10/12...
- Said shocks should be okay 10/10, maybe 10/12 but toward the limit.
- Don't advertise but are willing to revalve new Ohlins dampers to suit specified springs for no additional charge, if purchased from them. It's a value they offer to differentiate from other mail-order shops.
- They see very few Ohlins R&T kits coming in for service which makes them think the product is well built and reliable.
Called AST-USA, kinda (972.424.3700). Can't remember the shop name, but they used to be AST-USA till the contract expired. Still dealing with the product though.
- Again, very nice folks who spent plenty of time on the phone.
- Asking what they offer for a street / HPDE application led to their 5100 of which they had a set built sitting in Holland a customer backed out of. $2600 w/o springs or top hats.
- When asked to compare to Ohlins R&T, they said it's really kind of a draw at that price level between the top shelf vendors. I mentioned the Ohlins come complete with springs, hats, etc and it was suggested that it'd be a better buy. He recounted a number of recent builds for domestic shops, the specifications and cost for reference.
- On the DFV thing, it was his opinion that the AST's likely could be valved to have the same performance but it'd take some work to get the same result. Ohlins is more of an out the door package.
In the end I ordered the R&T's from a shop here in town who sell both Ohlins and AST. He gave me a good break off list and worked some other stuff in too. Pretty sure I'll be stoked on 8/10 or 10/10 rates to balance street civility with roll control on track.
Thanks to all for the insight.
Joined: Jul 2002
Posts: 1,733
Likes: 154
From: Why do they always call the Evo the Dark Side?
I don't see pricing for them anywhere but AST 5100's with the optional Double Digressive Pistons should offer better ride quality (especially with softer adjustment settings) than with standard pistons. I'm sure if you call AST USA they can give you more info and a quote.
More info on DDP:
AST's extremely digressive "DDP" piston was developed for GRAND-AM racing and gives drivers and race engineers the best of both worlds. Drivers love the low speed damping response and body control, while race engineers love the “blow off” (the knee point digression, shown in the dyno plot below), with a tapering off of the rebound forces at high shaft velocities. An unintended benefit of this piston was exceptional ride quality at high bypass settings (softer rebound knob adjustment).
When the rebound adjustment is set to soft, the damper curve looks similar to an OEM street shock profile. When the rebound adjustment is set to firmer settings, the damper curve looks like a race shock. The most critical portion of the dyno plot area is affected the most - the portion at low shaft speeds. So much in racing happens at 0-3 inches per second shaft velocities, and that's where these pistons really step up the damping forces, when adjusted firmer. The graph of shock dyno plots for typical compression and rebound curves from the 4150 are shown above. The changes are from adjustments to the rebound knob every two clicks (of twelve), and you can see the digressive nature of the plot. Basically, the super-digressive curve for the rebound that these new DDP pistons can achieve makes for a “Jekyll and Hyde” shock - one that offers a soft street ride and firm race car track performance in ONE shock - all with the turn of a knob.
More info on DDP:
AST's extremely digressive "DDP" piston was developed for GRAND-AM racing and gives drivers and race engineers the best of both worlds. Drivers love the low speed damping response and body control, while race engineers love the “blow off” (the knee point digression, shown in the dyno plot below), with a tapering off of the rebound forces at high shaft velocities. An unintended benefit of this piston was exceptional ride quality at high bypass settings (softer rebound knob adjustment).
When the rebound adjustment is set to soft, the damper curve looks similar to an OEM street shock profile. When the rebound adjustment is set to firmer settings, the damper curve looks like a race shock. The most critical portion of the dyno plot area is affected the most - the portion at low shaft speeds. So much in racing happens at 0-3 inches per second shaft velocities, and that's where these pistons really step up the damping forces, when adjusted firmer. The graph of shock dyno plots for typical compression and rebound curves from the 4150 are shown above. The changes are from adjustments to the rebound knob every two clicks (of twelve), and you can see the digressive nature of the plot. Basically, the super-digressive curve for the rebound that these new DDP pistons can achieve makes for a “Jekyll and Hyde” shock - one that offers a soft street ride and firm race car track performance in ONE shock - all with the turn of a knob.
It definitely rides better on the street than it did before the DDP's. I made other setup changes at the same time - switching to ZII's, etc - so I can't 100% speak to how much better the car handles... all I know is that the car is currently quite awesome.
Has anyone ever seen charts for the Ohlins? I just kind of infer that they're digressive from the behavior, but don't actually know. I wonder if it's possible to see the blow-off on a chart.
One of the big selling points for the AST 5x00 shocks is upgradeability. Does anyone know how much it costs to go from 5100s to 5200s? I've asked a vendor and e-mailed AST directly, but I'm stilling waiting on a response.
I was set on the 5200s, but by the time I finally convinced myself to pull the trigger on them it looks like they've raised their prices quite a bit. So I think I'll just start with the 5100s.
I was set on the 5200s, but by the time I finally convinced myself to pull the trigger on them it looks like they've raised their prices quite a bit.
So I think I'll just start with the 5100s.
I'm probably one of the few people that have used both AST 5100s and Ohlin DFVs. I would give the OTS ASTs the advantage in valving to handle heavier springs and the Ohlin's the advantage with body length adjustment. The AST's are also upgradeable to 5200 or 5300s where I think you need to buy Flags to get double adjustable with the Ohlins. Could be wrong on that though.
Since I have both sets in the garage right now, I sort of have a similar equal weighted decision on which to run. So here's what I think for me,
AST 5100s - Amazing, kick *** shocks. Have plenty of adjustment to handle the range of 10k to 16k Ive thrown at them. Perhaps a little more compression is needed for heavier rates though. At 12k they seem perfect. The lack of body height adjustment is a moderate annoyance. I don't even bother with the helpers cause they aren't near long enough and with my tire I need that extra clearance. Basically just set the car down easy and help the spring into place. NBD.
The Vorschlag top hats are worlds better than the thin Ohlins and come with built in caster. The bearings are massive and they have a bearing in the top to rotate so their is no springs bind if you're not running a Torrington bearing (these are a few hundred $$ extra option though).
Ride is just fine with these on lower rates but don't expect anything to work great at 700lb/in or higher. You just don't have the compression travel under static load so you unload without much effort in a rebound. That gives a feeling of harshness. Can be fixed using Tender springs (not low rate helpers) which I have but took off for clearance with the 285 BFGs.
Ohlin DFV - Super comfy at 10k/10k with the rebound turned down. 12ks (700) gets into the same situation as mentioned above. Less travel for a given load means fully unloading more often. Valving seems stretched at 12k but still works especially if lots/tracks are relatively smooth.
I really like having the body height adjustment after having other setups with it, hard to go back even if it doesn't really matter.
And the #1 biggest reason for me on the Ohlin's, Local support. I can drive these to a shop for valving and shock dynos. That makes a big difference for me because I'm not one to leave things as is.
BTW, I'm also selling my ASTs. Similar to what the other guy is selling but with Vorschlag plates and buyers choice of spring rates in 10k, 12k, and 16k with helpers or tenders. I just haven't posted mine to not undercut the other guy. Give his thread a chance to sell first.
Since I have both sets in the garage right now, I sort of have a similar equal weighted decision on which to run. So here's what I think for me,
AST 5100s - Amazing, kick *** shocks. Have plenty of adjustment to handle the range of 10k to 16k Ive thrown at them. Perhaps a little more compression is needed for heavier rates though. At 12k they seem perfect. The lack of body height adjustment is a moderate annoyance. I don't even bother with the helpers cause they aren't near long enough and with my tire I need that extra clearance. Basically just set the car down easy and help the spring into place. NBD.
The Vorschlag top hats are worlds better than the thin Ohlins and come with built in caster. The bearings are massive and they have a bearing in the top to rotate so their is no springs bind if you're not running a Torrington bearing (these are a few hundred $$ extra option though).
Ride is just fine with these on lower rates but don't expect anything to work great at 700lb/in or higher. You just don't have the compression travel under static load so you unload without much effort in a rebound. That gives a feeling of harshness. Can be fixed using Tender springs (not low rate helpers) which I have but took off for clearance with the 285 BFGs.
Ohlin DFV - Super comfy at 10k/10k with the rebound turned down. 12ks (700) gets into the same situation as mentioned above. Less travel for a given load means fully unloading more often. Valving seems stretched at 12k but still works especially if lots/tracks are relatively smooth.
I really like having the body height adjustment after having other setups with it, hard to go back even if it doesn't really matter.
And the #1 biggest reason for me on the Ohlin's, Local support. I can drive these to a shop for valving and shock dynos. That makes a big difference for me because I'm not one to leave things as is.
BTW, I'm also selling my ASTs. Similar to what the other guy is selling but with Vorschlag plates and buyers choice of spring rates in 10k, 12k, and 16k with helpers or tenders. I just haven't posted mine to not undercut the other guy. Give his thread a chance to sell first.
Have you had your Ohlins setup revalved for the higher spring rates yet? If so, can you comment on how the revalved setup compares to the 5100s with similar >10K spring rates? This is really what I'm most curious about, especially after someone hinted in this thread that a certain shop is willing to revalve the Ohlins at no additional cost.
It seems like almost everyone gets caught in the same ohlins orbit.... They are recognized as the best bang for the buck for 90% of the people on the forum but those of use spending $3000 probably want something more suited to track duty. Once you start running wide sticky race tires even the 10k fronts are too soft. Without a revalve this leaves you with two options: 12k/10k which isn't optimum but is within the valving range or 12k/12k which puts you outside of their recommended settings.
That is my entire complaint really ..... Ohlins ship with 10k/8k valving but how many people to you hear buying softer springs? None. If they would have shipped with 10k/12k pretty much everyone would have been happy. You would still have the option to run 8k/10k, 10k/10k, 12k/12k or 12k/14k. It would just make more sense to sell them that way.
As for buying them from a race shop such as works... they don't revalve them they simply swapped the springs around. No different than what I can do in 15 minutes at home.
Therefore I wouldn't recommend them for someone that plans to be on track with sticky tires unless you want to revalve the rears right from the get go. Getting them revalved to 12k would allow you to run the above mentioned rates.
That is my entire complaint really ..... Ohlins ship with 10k/8k valving but how many people to you hear buying softer springs? None. If they would have shipped with 10k/12k pretty much everyone would have been happy. You would still have the option to run 8k/10k, 10k/10k, 12k/12k or 12k/14k. It would just make more sense to sell them that way.
As for buying them from a race shop such as works... they don't revalve them they simply swapped the springs around. No different than what I can do in 15 minutes at home.
Therefore I wouldn't recommend them for someone that plans to be on track with sticky tires unless you want to revalve the rears right from the get go. Getting them revalved to 12k would allow you to run the above mentioned rates.
i got a set of gerard spec ohlins RT's used and 1 year post rebuild from PSI...for $1500. probabaly the best money i spent on the car so far. the street manners are better than the bilstein/gtworx combo i replaced. they have done well on the track but the 8k/10k is a tad soft for rs3's from what i found on tight tracks.
fyi, if anyone finds a gerard spec set, per him they are valved to handle up to i believe 14l/16k.
fyi, if anyone finds a gerard spec set, per him they are valved to handle up to i believe 14l/16k.
One of the big selling points for the AST 5x00 shocks is upgradeability. Does anyone know how much it costs to go from 5100s to 5200s? I've asked a vendor and e-mailed AST directly, but I'm stilling waiting on a response.
I was set on the 5200s, but by the time I finally convinced myself to pull the trigger on them it looks like they've raised their prices quite a bit. So I think I'll just start with the 5100s.
I was set on the 5200s, but by the time I finally convinced myself to pull the trigger on them it looks like they've raised their prices quite a bit.
So I think I'll just start with the 5100s.Now I really wish I had just pulled the trigger on those 5200s in the middle of last year when they were only $4100.
FWIW, here's the dyno of my left rear Moton Clubsport after I had the pistons switched out for the DDP's.
...
It definitely rides better on the street than it did before the DDP's. I made other setup changes at the same time - switching to ZII's, etc - so I can't 100% speak to how much better the car handles... all I know is that the car is currently quite awesome.
...
It definitely rides better on the street than it did before the DDP's. I made other setup changes at the same time - switching to ZII's, etc - so I can't 100% speak to how much better the car handles... all I know is that the car is currently quite awesome.
http://www.golfmkv.com/forums/showpo...3&postcount=17
Okay, I finally managed to get a rough estimate on the 5100->5200 upgrade cost: About $3000 for parts and labor. I guess that's not too terrible, considering the price difference between the 5200 and the 5100 is now $2400 under the new, higher AST pricing.
Now I really wish I had just pulled the trigger on those 5200s in the middle of last year when they were only $4100.
Now I really wish I had just pulled the trigger on those 5200s in the middle of last year when they were only $4100.
5300 AST for any race on track or Hillclimb is an awesome suspension. You can't beat it for a same price. Those coils are no joke.
Last edited by Robevo RS; Feb 21, 2014 at 01:41 PM.