Racing Seat, Harness Install - DIY (Cobra Suzuka, Schroth Profi-6) (detailed)
09-16-2010, 10:37 PM
#1
Safety Car
Thread Starter
Racing Seat, Harness Install - DIY (Cobra Suzuka, Schroth Profi-6) (detailed)
Some notes if anyone is considering this seat:
- I am 5-10, 160-165lb (32" waist) - seat fits like a glove, perfect
- to get a proper (safe) fit in a C5, you need to recline the seat. A lot. More than the standard side mount brackets will allow (other option is to mount those to a base bracket which is angled). I used the Sparco base as a starting point and welded 1/8" (what FIA specs) steel to form a cradle for the seat. The rear is essentially on the floor (but spaced up 1/8" to avoid rubbing/creaking/etc), the front is up ~5". You will need to position the base closer to the wheel pedals when like this. This position gives my head w/helmet tons of room (3-4") and the position is super comfy for street or track driving. When more upright, the A-pillar and roof (top of window) would break my neck in a crash. Be sure to grind, then file all edges so they are smooth to prevent cut fingers and more importantly, cuts to your harnesses.
- The seat allows tons of lateral room - the shoulder wings aren't close to the door, there is plenty of room for the OEM belt receiver.
- Not too hard to get in/out of - much easier with steering wheel tilt. I have a Cobra Monaco Pro for the pass. seat and it is harder to get into b/c of the higher mid-side section (though offers a bit less gripping once seated, but will fit any size instructor).
- I chose this b/c of the wear patches, Kevlar construction, and the tougher fabric than the Sparco seats. Def worth it. I am almost thinking I should have gotten the Sebring, with the side helmet braces since I don't think they would make entry/exit much more difficult (contrary to what I read here).
-I have a Hutchens (Safety Solutions) Hybrid Pro Rage head/neck restraint - don't even realize it is on while driving (though would prob be the same w/any seat. Takes some practice to get on and to get used to moving to use the max available side vision (though for pit exit merges at first, be careful).
- Also - keep the seat angle in mind when ordering a head an neck restraint as it matters for some (though not the above - but does matter for the Hybrid model)
- Seat works great on the track - allows me to fully concentrate on driving as opposed to wearing out my upper body bracing myself w/stock seats.
The seat is half the install, the harnesses are the other half:
- I went gonzo on the install since it is my life on the line:
- For the sub belt anchor - I installed a 1/8" steel plate w/ 1/2" bends on either side (i.e. "channel" - it looks like a digital "c") under the car, welded to the outer frame rail and inner metal. It is key to mount this piece against the balsa/alum composite floor for it to work properly (i.e. no flex). I also welded in a flat 1/8" steel plate on top of the composite floor (i.e. in the cabin), top of the eyelet from wandering - so the eyelet is braced above the anchoring bolt and just below the eyelet. I welded this flat piece (4" wide x floor width) to the metal on either side of the floor (with some tabs), and with some 1/8" square tubing welding longitudinally (towards F/R) to prevent the any movement of the heads of the eyelets. I felt this was necessary b/c of the 1" width of the floor and the forces involved in a crash - best to brace the top and bottom of the eyelet. This setup is a bit safer than any of the bolt-on solutions with anchor in the incorrect position and to mounts which might not be able to withstand the ton(s) of force in a crash. I could easily jack up the car by the plate mounted under the car, which is a good reference since it may face such force (suddenly) in a big crash. If you do this method - measure the width of the underside of the composite floor exactly, grind away the hardened glue so the underside plate sits flush, and use 4-5" mounting strips to connect this plate to the rails, which sits about 1/8" below the floor (i.e the composite floor is elevated vs. the frame rail/inner metal). Grind the rails/plate as necessary so the plate (this is the "c" channel plate) is perfectly flat against the composite floor, then hold the plate and mounting strips in place with a jack when welding. With overhead welding - use plenty of heat and a bit higher wire feed speed (for MIG) to lay a decent bead. Fully grind the paint off the rail/inner metal. Weld a little at a time to keep fires/warping to a minimum. Perfect welds are not key here - you just need to held that plate in place - in a crash the force is upwards. I tacked the mounting strips to the rail/inner metal/mounting plate, then welded them up, all with overhead welding with a jack/holding everything in place to void warping. Warping in the devil here since you need these things perfectly mated to work properly in a crash. The key here is to spread the load as widely as possible, which a 4" wide plate, ~19 9/16" wide will do. This isn't a totally original idea as the factory did the same with the underbody seat mounts, but this is the factory technique on steroids (much thicker steel, much wider load distribution, much more rigid plate).
- the lap belts are mounted to the inside of the rear seat studs (16" width (IIRC), per the Schroth instructions). I am not totally happy with using the factory strap and will upgrade this by grinding the slight front/rear edges of the rear seat underfloor mount strap (flimsy 1/16" steel) and weld in a larger plate to spread the load.
- AS&M harness bar - this and the BK bars get the should strap mounts to the correct height/angle (i.e low enough) when mounting. This bar has some flex (1/16"-1/8") and relies on the rear bulkhead for reinforcement. I need to weld in a shim of steel to remove this flex.
- don't forget to zip tie some foam on the harness bar to properly space the harness belts.
- the Schroth instructions are quite good - I'd read them and keep that info in mind even if using non-Schroth belts
The Profi harnesses are very nice, very adjustable and allow a pull-to-center option (required if you want a safe, tight fit). The anti-sub strap is spaced (critical) and they are FIA - good for 5 years so they pay for themselves if you ignore the time value of money (which we do since we **** it away on race cars). I chose them b/c of the 2" lap belts (safer than 3" b/c of they avoid sitting on the pelvic crest). No need for 2" belts up top when using a Hutchens (vs with a HANS, which tests a bit worse than the Hutchens).
I went though a bit of work (i.e. produce a bit of garbage or "practice") - more than necessary to come up with the simplest/safest solution - so hopefully this will save some work in the future.
I would think the "GT" versions of the Suzuka would fit fine as I have a bit of room btw the tunnel and the lower OEM belt anchor. If you ditch the lower OEM belt achor - even more room to play.
Be sure to try all this stuff out BEFORE you get the track after the initial install. Always make sure you are fully belted in before you head onto the track. Call the mfg if you have any questions about where the belt receiver should sit, harness angles, etc. This is life or death!
Additional comments/suggestions welcome...the thick composite floor adds another layer of issues that needs to be addressed in a harness install.
Thanks to Randy @ DRM for posting some "wall of shame" pics of a poor seat install for getting me thinking about this - I think in that instance a prior shop bolted the harnesses/seat directly to the composite floor. If you have ever drilled through the floor, you would immediately realize such a setup would cause serious bodily harm/death in a crash.
So, I am screwed in a side impact (possible serious bodily harm) and a full cage w/door bars should be added, but hopefully that is less of an issue in TT's and HPDEs. I realize this is wishful thinking.
- I am 5-10, 160-165lb (32" waist) - seat fits like a glove, perfect
- to get a proper (safe) fit in a C5, you need to recline the seat. A lot. More than the standard side mount brackets will allow (other option is to mount those to a base bracket which is angled). I used the Sparco base as a starting point and welded 1/8" (what FIA specs) steel to form a cradle for the seat. The rear is essentially on the floor (but spaced up 1/8" to avoid rubbing/creaking/etc), the front is up ~5". You will need to position the base closer to the wheel pedals when like this. This position gives my head w/helmet tons of room (3-4") and the position is super comfy for street or track driving. When more upright, the A-pillar and roof (top of window) would break my neck in a crash. Be sure to grind, then file all edges so they are smooth to prevent cut fingers and more importantly, cuts to your harnesses.
- The seat allows tons of lateral room - the shoulder wings aren't close to the door, there is plenty of room for the OEM belt receiver.
- Not too hard to get in/out of - much easier with steering wheel tilt. I have a Cobra Monaco Pro for the pass. seat and it is harder to get into b/c of the higher mid-side section (though offers a bit less gripping once seated, but will fit any size instructor).
- I chose this b/c of the wear patches, Kevlar construction, and the tougher fabric than the Sparco seats. Def worth it. I am almost thinking I should have gotten the Sebring, with the side helmet braces since I don't think they would make entry/exit much more difficult (contrary to what I read here).
-I have a Hutchens (Safety Solutions) Hybrid Pro Rage head/neck restraint - don't even realize it is on while driving (though would prob be the same w/any seat. Takes some practice to get on and to get used to moving to use the max available side vision (though for pit exit merges at first, be careful).
- Also - keep the seat angle in mind when ordering a head an neck restraint as it matters for some (though not the above - but does matter for the Hybrid model)
- Seat works great on the track - allows me to fully concentrate on driving as opposed to wearing out my upper body bracing myself w/stock seats.
The seat is half the install, the harnesses are the other half:
- I went gonzo on the install since it is my life on the line:
- For the sub belt anchor - I installed a 1/8" steel plate w/ 1/2" bends on either side (i.e. "channel" - it looks like a digital "c") under the car, welded to the outer frame rail and inner metal. It is key to mount this piece against the balsa/alum composite floor for it to work properly (i.e. no flex). I also welded in a flat 1/8" steel plate on top of the composite floor (i.e. in the cabin), top of the eyelet from wandering - so the eyelet is braced above the anchoring bolt and just below the eyelet. I welded this flat piece (4" wide x floor width) to the metal on either side of the floor (with some tabs), and with some 1/8" square tubing welding longitudinally (towards F/R) to prevent the any movement of the heads of the eyelets. I felt this was necessary b/c of the 1" width of the floor and the forces involved in a crash - best to brace the top and bottom of the eyelet. This setup is a bit safer than any of the bolt-on solutions with anchor in the incorrect position and to mounts which might not be able to withstand the ton(s) of force in a crash. I could easily jack up the car by the plate mounted under the car, which is a good reference since it may face such force (suddenly) in a big crash. If you do this method - measure the width of the underside of the composite floor exactly, grind away the hardened glue so the underside plate sits flush, and use 4-5" mounting strips to connect this plate to the rails, which sits about 1/8" below the floor (i.e the composite floor is elevated vs. the frame rail/inner metal). Grind the rails/plate as necessary so the plate (this is the "c" channel plate) is perfectly flat against the composite floor, then hold the plate and mounting strips in place with a jack when welding. With overhead welding - use plenty of heat and a bit higher wire feed speed (for MIG) to lay a decent bead. Fully grind the paint off the rail/inner metal. Weld a little at a time to keep fires/warping to a minimum. Perfect welds are not key here - you just need to held that plate in place - in a crash the force is upwards. I tacked the mounting strips to the rail/inner metal/mounting plate, then welded them up, all with overhead welding with a jack/holding everything in place to void warping. Warping in the devil here since you need these things perfectly mated to work properly in a crash. The key here is to spread the load as widely as possible, which a 4" wide plate, ~19 9/16" wide will do. This isn't a totally original idea as the factory did the same with the underbody seat mounts, but this is the factory technique on steroids (much thicker steel, much wider load distribution, much more rigid plate).
- the lap belts are mounted to the inside of the rear seat studs (16" width (IIRC), per the Schroth instructions). I am not totally happy with using the factory strap and will upgrade this by grinding the slight front/rear edges of the rear seat underfloor mount strap (flimsy 1/16" steel) and weld in a larger plate to spread the load.
- AS&M harness bar - this and the BK bars get the should strap mounts to the correct height/angle (i.e low enough) when mounting. This bar has some flex (1/16"-1/8") and relies on the rear bulkhead for reinforcement. I need to weld in a shim of steel to remove this flex.
- don't forget to zip tie some foam on the harness bar to properly space the harness belts.
- the Schroth instructions are quite good - I'd read them and keep that info in mind even if using non-Schroth belts
The Profi harnesses are very nice, very adjustable and allow a pull-to-center option (required if you want a safe, tight fit). The anti-sub strap is spaced (critical) and they are FIA - good for 5 years so they pay for themselves if you ignore the time value of money (which we do since we **** it away on race cars). I chose them b/c of the 2" lap belts (safer than 3" b/c of they avoid sitting on the pelvic crest). No need for 2" belts up top when using a Hutchens (vs with a HANS, which tests a bit worse than the Hutchens).
I went though a bit of work (i.e. produce a bit of garbage or "practice") - more than necessary to come up with the simplest/safest solution - so hopefully this will save some work in the future.
I would think the "GT" versions of the Suzuka would fit fine as I have a bit of room btw the tunnel and the lower OEM belt anchor. If you ditch the lower OEM belt achor - even more room to play.
Be sure to try all this stuff out BEFORE you get the track after the initial install. Always make sure you are fully belted in before you head onto the track. Call the mfg if you have any questions about where the belt receiver should sit, harness angles, etc. This is life or death!
Additional comments/suggestions welcome...the thick composite floor adds another layer of issues that needs to be addressed in a harness install.
Thanks to Randy @ DRM for posting some "wall of shame" pics of a poor seat install for getting me thinking about this - I think in that instance a prior shop bolted the harnesses/seat directly to the composite floor. If you have ever drilled through the floor, you would immediately realize such a setup would cause serious bodily harm/death in a crash.
So, I am screwed in a side impact (possible serious bodily harm) and a full cage w/door bars should be added, but hopefully that is less of an issue in TT's and HPDEs. I realize this is wishful thinking.
