Ohlinds R&T front end clunk RESOLVED

[Craigito]

About a month ago the car started to develop a fairly significant clunking noise from what felt like the front left suspension which was mostly evident (noisy) at low speeds. I took the car in to my maintenance mechanic first to see if they could diagnose it. They confirmed everything looked tightened up their opinion was that likely was coming from the strut itself but without taking the strut off and inspecting it they couldn’t be sure. I then took it to my aftermarket performance mechanic for a second opinion (before I started dumping money into fixing it). They confirmed the same. At that time I told them to go ahead and take the front struts off and see if they could confirm that was the issue. After inspecting both struts they confirmed they could feel a very very slight amount of play/movement in the left strut whereas the right shock had zero play. At that point I had them go ahead and replace both front struts hoping that would fix it. This replacement mitigated the noise entirely. The nice thing is the shop was able to replace just the front struts (they had them in stock) and I didn’t have to replace the entire system. So the point of all this is to say that even with a barely perceptible amount of play in the strut that translated to a very obvious clunk from the front end. I have roughly 40k miles on the system so at some point the rears will also need to be replaced. But at least I was able to walk out of there with the immediate situation fixed and not have to cut both my arms and legs off to pay for it. The struts were about $500 each. With all the diagnosis and labor was able to walk out for less than $1500. I also noticed after replacement the feel from the front and tightened up a lot (a good thing). Over three years it’s hard to perceive the softness that developed but it was clear when I drove it. Happy it was resolved.

[mike082802]

glad you got it fixed. just curious what shop had the ohlins front struts in stock? that is super rare, i had a problem with one of my rears and had to wait over 2 months to get one from europe.

[M3SQRD]

Ohlins R&T dampers can be fully rebuilt (and custom valved) for a fraction of the cost of replacement dampers.

[jbalabas]

Originally Posted by M3SQRD

Ohlins R&T dampers can be fully rebuilt (and custom valved) for a fraction of the cost of replacement dampers.

I've tried emailing ohlins to see if I can mimic the ttx shock tune on the R&T shocks. Or at least find out how different the damping tune is. My buddies shop is an ohlins dealer so I just gotta figure out the shim stack.

[M3SQRD]

Originally Posted by jbalabas

I've tried emailing ohlins to see if I can mimic the ttx shock tune on the R&T shocks. Or at least find out how different the damping tune is. My buddies shop is an ohlins dealer so I just gotta figure out the shim stack.

The TTX and R&T couldn’t be more different! The TTX is a 2/3/4 way “twin tube” damper (it is but how it works is way more complicated) and the R&T is a 1-way adjustable monotube damper. No parts are shared between them. The valve technology isn’t remotely similar. I’d contact 3DM or Performance Shock Inc (PSI). They rebuild and revalve both dampers so they can explain the limitations of the R&T damper.

[jbalabas]

Originally Posted by M3SQRD

The TTX and R&T couldn’t be more different! The TTX is a 2/3/4 way “twin tube” damper (it is but how it works is way more complicated) and the R&T is a 1-way adjustable monotube damper. No parts are shared between them. The valve technology isn’t remotely similar. I’d contact 3DM or Performance Shock Inc (PSI). They rebuild and revalve both dampers so they can explain the limitations of the R&T damper.

I'm fairly familiar with the ins and outs of suspension and understand how different the 2 shocks are in construction and design. But in the end a damper is a damper, fluid moves through an orifice. The ttx damping curve can be plotted on a dyno. I just wanna see how it compares and how i can get the compression and rebound tune of the R&T closer. 4 1 or zero adjustments every shock has a base tune those adjustments work off. Of course the twin tube architecture is superior with circular oil flow but a monotube can feel similar. Obviously the R&T will never keep up when things get rowdy but it can have a similar base tune. Anyways my 2 cents.

[Craigito]

Originally Posted by M3SQRD

Ohlins R&T dampers can be fully rebuilt (and custom valved) for a fraction of the cost of replacement dampers.

PSI in Sonoma quoted me $1400 to rebuild all 4. When you consider this is my DD and I would have to pay my shop twice to put on my OE setup while I ship them out and then swap again to install plus the shipping costs to/from there seemed to be little reason to go that route.

[Craigito]

Originally Posted by mike082802

glad you got it fixed. just curious what shop had the ohlins front struts in stock? that is super rare, i had a problem with one of my rears and had to wait over 2 months to get one from europe.

I’d rather not say in case it’s a no no. They had a full F82 R&T kit already there (not sure why) and they said they could just order the front struts to make the kit whole again after they did my work. I got lucky on the timing for sure that I could get it all done on the same visit. I think they said you could order individual parts of the kit from 3DM IIRC.

[M3SQRD]

Originally Posted by Craigito

PSI in Sonoma quoted me $1400 to rebuild all 4. When you consider this is my DD and I would have to pay my shop twice to put on my OE setup while I ship them out and then swap again to install plus the shipping costs to/from there seemed to be little reason to go that route.

Dang! $1400 sounds expensive. It was a few years ago but I was quoted $250/damper on my Mini CS R&T dampers. Didn’t think about the costs of swapping suspensions because I’d pull them off in my garage. Two new dampers for $1500 was your best option.

[M3SQRD]

Originally Posted by jbalabas

I'm fairly familiar with the ins and outs of suspension and understand how different the 2 shocks are in construction and design. But in the end a damper is a damper, fluid moves through an orifice. The ttx damping curve can be plotted on a dyno. I just wanna see how it compares and how i can get the compression and rebound tune of the R&T closer. 4 1 or zero adjustments every shock has a base tune those adjustments work off. Of course the twin tube architecture is superior with circular oil flow but a monotube can feel similar. Obviously the R&T will never keep up when things get rowdy but it can have a similar base tune. Anyways my 2 cents.

True. The TTX works very differently from a conventional twin tube damper. I know monotubes can perform just as well as the TTX. I’m running MCS 2WR setups on all of my current cars. I prefer MCS over the TTX which are limited in spring rate changes before needing to be revalved. Absolutely, it’s all just fluid moving through a restriction (orifice) but the DFV technology in the R&T controls flow through the same orifice in rebound and compression. You might be able to match one curve but both will be a bit challenging. Also, R&T alters both rebound and compression in the same direction for each adjustment, and compression is a relatively small % of the rebound change. High-speed blowoff characteristics will different as well. There’s a good YouTube video discussing the R&T F8x/F87 dampers. Here a link if you haven’t seen it:
https://youtu.be/m5kJmbSEkVo?si=C7gRWWvk-sWFEY0O

[mike082802]

Originally Posted by M3SQRD

Dang! $1400 sounds expensive. It was a few years ago but I was quoted $250/damper on my Mini CS R&T dampers. Didn’t think about the costs of swapping suspensions because I’d pull them off in my garage. Two new dampers for $1500 was your best option.

whats mcs run for a rebuild now? i would assume the same $350 a corner. I almost went mcs 1 ways but after talking with a few shops i wasn't a good enough driver at the time to notice a difference and they told me to save my money. i probably have 23k miles and at least 25 track days on the ohlins r&t in the last 3 years.

[jbalabas]

Originally Posted by M3SQRD

True. The TTX works very differently from a conventional twin tube damper. I know monotubes can perform just as well as the TTX. I’m running MCS 2WR setups on all of my current cars. I prefer MCS over the TTX which are limited in spring rate changes before needing to be revalved. Absolutely, it’s all just fluid moving through a restriction (orifice) but the DFV technology in the R&T controls flow through the same orifice in rebound and compression. You might be able to match one curve but both will be a bit challenging. Also, R&T alters both rebound and compression in the same direction for each adjustment, and compression is a relatively small % of the rebound change. High-speed blowoff characteristics will different as well. There’s a good YouTube video discussing the R&T F8x/F87 dampers. Here a link if you haven’t seen it:
https://youtu.be/m5kJmbSEkVo?si=C7gRWWvk-sWFEY0O

I understand the limitations of my current set up. I'm not saying I can make a R&T ride like a ttx. I just want to ensure they have a similar damping curve and remove a little of the dual duty and make more track focused. I have the ability to rebuild for cheap so why not see what you can improve.

[M3SQRD]

Originally Posted by mike082802

whats mcs run for a rebuild now? i would assume the same $350 a corner. I almost went mcs 1 ways but after talking with a few shops i wasn't a good enough driver at the time to notice a difference and they told me to save my money. i probably have 23k miles and at least 25 track days on the ohlins r&t in the last 3 years.

Last I checked it was $350/corner for a standard rebuild. My three sets all need rebuilding at about the same time.

[M3SQRD]

Originally Posted by jbalabas

I understand the limitations of my current set up. I'm not saying I can make a R&T ride like a ttx. I just want to ensure they have a similar damping curve and remove a little of the dual duty and make more track focused. I have the ability to rebuild for cheap so why not see what you can improve.

What you’re attempting to do makes sense to me. Getting damping curves for TTX F8x dampers (and finding thru rod vs non-thru rod designs) valved tor the same, or similar, rates that you’re running won’t be easy. I recall an F8x owner selling his TTX setup and he had included pictures of the damper dyno plots. They had a large number of curves for R and C settings. However, this was for a pure track setup with something like F/R 1000/1000 lbf/in with a functional aero setup (really high low speed C damping, definitely well overdamped).

[jbalabas]

Originally Posted by M3SQRD

What you’re attempting to do makes sense to me. Getting damping curves for TTX F8x dampers (and finding thru rod vs non-thru rod designs) valved tor the same, or similar, rates that you’re running won’t be easy. I recall an F8x owner selling his TTX setup and he had included pictures of the damper dyno plots. They had a large number of curves for R and C settings. However, this was for a pure track setup with something like F/R 1000/1000 lbf/in with a functional aero setup (really high low speed C damping, definitely well overdamped).

I like to tinker and when your best friend is an ohlins certified tech why not have some fun and see how you can improve the damping. It can always be reverted to stock.