About a year ago, I was knee deep in preparing for further power upgrades - Hydra HP650 turbos, ported head with Schrick cams, and supporting items to put us in the 600whp range. I was particularly concerned about power management and had been discussing this with @barry@3DM . Barry had been doing some testing with the motorsport grade Öhlins TTX dampers, Such dampers are used on DTM touring cars, NASCAR, and the track-ready BMW M4 GT4 and BMW M6 GT3. They are effectively non-existent in street and HPDE applications. In testing, Barry found the TTX ability to manage both putting power down and handling uneven road surfaces (even apex berms) to be far more capable than conventional dampers.
Barry and I began discussing a hybrid suspension, where the rear would be built with Öhlins TTX dampers to help facilitate rear grip with the significant power increases that are planned. This effort became the basis for the 3DM Hybrid TTX Series suspensions: using Öhlins R&T front dampers to manage cost (front TTX struts add significant cost) in conjunction with Öhlins TTX rear dampers to better manage high horsepower applications. Today there are several 3DM Hybrid TTX suspensions in the wild, including on @ShocknAwe's car here on Spoolstreet, and several more in the making for other E9x and E8x customers. As well there are track car applications that Barry has built, to include E30 M3, E36 M3, E46 M3, with F2x *M235i R) in flight, etc. In many ways, this Z4 is the mule that pushed into this solution approach.
Along the way we decided to build a full 3DM TTX suspension for the Z4, to see if a full road-going TTX-based BMW suspension could be developed, and to see how far a street car’s handling capability could be realized. Though these pictures look like simple finished product, there was a lot of measurement and development work, along with a variety of parts machined and fabricated to get to achieve this configuration.
For the Z4, the 3DM TTX is an upgrade from an existing full M3 suspension with Öhlins R&T dampers. My frame of reference is far from a stock m-sport suspension. Let me jump to the punchline: in our initial 15 mile test drive on pave-in-place roads, the only way I can describe the new suspension is that it is like driving a hovercraft directly attached to one’s brain.
Simply unbelievable. First observations:
In this thread, I’d like to share some photos and description of the build process. We are currently performing a round of changes, based on initial testing. We are far enough along that some public posting is worth sharing. I’m also hoping, for those with technical interest, that @barry@3DM might chime in and explain why these dampers are not like traditional mono-tube shocks, and different from other brand motorsport shocks with external reservoirs, etc.
I’d like to thank @barry@3DM for all his efforts on this undertaking - without his expertise this capability would be unimaginable, much less realized. Given the development work necessary to make this a functioning street suspension, I would venture to say that there are likely no street-going BMW’s with complete suspensions based on the TTX race damper technology.
A year of discussion, planning, and eight months of work. While we are not done, I can say this car drives like nothing I’ve driven before, and it was worth it.
Filippo
Barry and I began discussing a hybrid suspension, where the rear would be built with Öhlins TTX dampers to help facilitate rear grip with the significant power increases that are planned. This effort became the basis for the 3DM Hybrid TTX Series suspensions: using Öhlins R&T front dampers to manage cost (front TTX struts add significant cost) in conjunction with Öhlins TTX rear dampers to better manage high horsepower applications. Today there are several 3DM Hybrid TTX suspensions in the wild, including on @ShocknAwe's car here on Spoolstreet, and several more in the making for other E9x and E8x customers. As well there are track car applications that Barry has built, to include E30 M3, E36 M3, E46 M3, with F2x *M235i R) in flight, etc. In many ways, this Z4 is the mule that pushed into this solution approach.
Along the way we decided to build a full 3DM TTX suspension for the Z4, to see if a full road-going TTX-based BMW suspension could be developed, and to see how far a street car’s handling capability could be realized. Though these pictures look like simple finished product, there was a lot of measurement and development work, along with a variety of parts machined and fabricated to get to achieve this configuration.
For the Z4, the 3DM TTX is an upgrade from an existing full M3 suspension with Öhlins R&T dampers. My frame of reference is far from a stock m-sport suspension. Let me jump to the punchline: in our initial 15 mile test drive on pave-in-place roads, the only way I can describe the new suspension is that it is like driving a hovercraft directly attached to one’s brain.
Simply unbelievable. First observations:
- The car glides over surfaces. Low-speed damping, to which I’ve never observed or given thought, is incredible. The TTX dampers take out all the little road imperfections that one typically associates to a high feedback suspension. Yet there is plenty of feedback and sensitivity - incredible low-speed damping.
- Road irregularities gobbled up. Barry had mentioned how well TTX dampers manage apex berms. On the road, this capability is evident with sharp asphalt irregularities, which are consumed with minimal jarring.
- Instant response. The car is not twitchy, but rather responds instantly to steering feedback. The switch to the F30 hub carrier certainly improves front-end geometry. I had to correct steer in several turns as I was providing too much turn-in, too soon, based on being acclimated to the previous suspension.
In this thread, I’d like to share some photos and description of the build process. We are currently performing a round of changes, based on initial testing. We are far enough along that some public posting is worth sharing. I’m also hoping, for those with technical interest, that @barry@3DM might chime in and explain why these dampers are not like traditional mono-tube shocks, and different from other brand motorsport shocks with external reservoirs, etc.
I’d like to thank @barry@3DM for all his efforts on this undertaking - without his expertise this capability would be unimaginable, much less realized. Given the development work necessary to make this a functioning street suspension, I would venture to say that there are likely no street-going BMW’s with complete suspensions based on the TTX race damper technology.
A year of discussion, planning, and eight months of work. While we are not done, I can say this car drives like nothing I’ve driven before, and it was worth it.
Filippo
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