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I have an Evo 9 for STU class autocross. I have a set of Sparco Evo seats in the car currently. I'm still using the stock belts.
(pardon the dog hair. Our dog has never been in the car, it just tracks in from me and sticks. If I was making a lint brush, I would make it out of Sparco Evo fabric as it is exceptionally good at trapping dog hair. but I digress)
The belt isn't as snug to my waist as it would be with normal seats because of the sidewalls of the seat. (Or whatever they're called, for the purposes of the post I'm calling them sidewalls ) (edit: bolsters! that's the word)
I don't drive the car on the street very much, but I do drive it to events rather than trailering.
I had forgotten about this until yesterday when I took it out for a Chick Fil A pickup (I hadn't driven it in 5 weeks or so). I'm trying to figure out what other folks in a similar situation do about this.
Some of the options:
* Deal with it
* Go back to the stock seats. I would kinda hate this for autocross. I was originally intending to keep the stock seats because they're Recaros, figuring that would be good enough - but they aren't. I would brace myself off the dead pedal a lot when autoxing. I'm not totally opposed to this; I'm not running as aggressive an autox schedule as I used to so it would matter less, but I would prefer to keep the seats (I do find them perfectly comfortable on the street)
* Re-route the OEM belt through the holes in the seat bolsters, similar to what you'd do with a 5 point harness. This would be fine on the left side but on the right side I would have to somehow relocate the seatbelt receptacle lower. I'm using the Bride FG rails (I think), maybe there's another aftermarket setup that would work better here or I could get a race shop to weld something.
* Run an ASM 4 point harness - Schroth or Takata Drift. The ASM part should prevent submarining, and I would think it would also mean less risk of basal skull fracture i.e. the thing that HANS fixes in a race car. There are flavors of this harness that are DOT approved for regular street use. This would fix the routing problem because the belt part is in the middle of the seat instead of on one side.
* Get different seats. Is there a fixed back out there that has shorter bolsters?
Thanks for any ideas!
Last edited by Butt Dyno; Jan 30, 2022 at 06:28 AM.
Have always run the Schroth ASM Autocontroll II (street legal) in all my track day cars (freedom of fwd torso movement and can be fully locked if needed)
Last edited by MinusPrevious; Jan 29, 2022 at 09:36 AM.
I have 6 point harnesses and race seats 24/7 in my Evo. Too lazy to swap back and forth to stock seats in my old (middle) age. What I do on the street is fasten the lap and sub belts of the harness, but not the shoulder harnesses, but still use the stock seat belt across my chest. The lap belt rides on the bolsters a bit, but it doesn't matter because the harness lap and sub belts hold me in snug.
In my other car where I have a Sparco race seat but no harness, I run the stock lap belt through the harness hole on the left side of the seat and use furniture making foam under the Sparco padding on the seat base to lift me up in the seat and effectively shorten the side bolsters, so that the lap belt is a little snugger on my waist.
I have 6 point harnesses and race seats 24/7 in my Evo. Too lazy to swap back and forth to stock seats in my old (middle) age. What I do on the street is fasten the lap and sub belts of the harness, but not the shoulder harnesses, but still use the stock seat belt across my chest. The lap belt rides on the bolsters a bit, but it doesn't matter because the harness lap and sub belts hold me in snug.
This is a combination I definitely would not have thought of - but I don't have a rollbar/harness bar/etc
Originally Posted by EVO8LTW
In my other car where I have a Sparco race seat but no harness, I run the stock lap belt through the harness hole on the left side of the seat and use furniture making foam under the Sparco padding on the seat base to lift me up in the seat and effectively shorten the side bolsters, so that the lap belt is a little snugger on my waist.
I had something like this in my first draft - effectively figuring out how to sit on a phone book so that the belt would go across my legs instead of the side bolsters. How much / how thick of a foam did you need to accomplish this?
I'm leaning towards an ASM harness at this point - it seems the most designed for my purposes overall - but not settled on anything yet.
This is a combination I definitely would not have thought of - but I don't have a rollbar/harness bar/etc
I had something like this in my first draft - effectively figuring out how to sit on a phone book so that the belt would go across my legs instead of the side bolsters. How much / how thick of a foam did you need to accomplish this?
I'm leaning towards an ASM harness at this point - it seems the most designed for my purposes overall - but not settled on anything yet.
Only a couple pieces of foam about 1-1/2” thick uncompressed. The side bolsters aren’t too high on the Pro 2000 seat and I’m not as thin as I used to be. The solution in the Evo is much better. I do have a six point bar in the car.
Posted in the wrong thread just now (hate doing this from my phone):
With my IX, I had a Racetech bucket seat with a Schroth Rallye 3 ASM harness, but I also left the stock belts in the car. When autocrossing, I would pull the Schroth harness from the back of the seat to the front to use, and for street driving, I would put the harness behind the seat and pull the stock belt to the front. Worked pretty well for 9 years.
Have no idea how you guys still run the stock belts in an EvO
You need a harness system to keep your butt (sensor) in the seat for a proper feel & position while driving on the track
IMHO the seat does most of the work, but I'm not doing track stuff with super sustained Gs.
I think I am going to call HMS Motorsport on Monday and talk through options. The 3" Takata Drift (made by Schroth) appeals to me (I had 3" harnesses in my old track Miata and liked them better than the 2" Schroth autocontrol I had in my old WRX for a while - also the Takata come in green!) but the Takata version doesn't have the detachable tail like the Schroth ones do. The more I think about it, the more I'm thinking I would want the autocontrol so that I have more freedom of movement when street driving.
IMHO the seat does most of the work, but I'm not doing track stuff with super sustained Gs.
I think I am going to call HMS Motorsport on Monday and talk through options. The 3" Takata Drift (made by Schroth) appeals to me (I had 3" harnesses in my old track Miata and liked them better than the 2" Schroth autocontrol I had in my old WRX for a while - also the Takata come in green!) but the Takata version doesn't have the detachable tail like the Schroth ones do. The more I think about it, the more I'm thinking I would want the autocontrol so that I have more freedom of movement when street driving.
If you get in a frontal collision with the Schroth autocontrol on the street, will the harness allow your body to move forward into the airbag so you have a more gradual decel in the crash like a stock 3-point? Otherwise, you risk a neck injury in a hard crash since you won’t have a head/neck restraint on.
IMHO the seat does most of the work, but I'm not doing track stuff with super sustained Gs.
I think I am going to call HMS Motorsport on Monday and talk through options. The 3" Takata Drift (made by Schroth) appeals to me (I had 3" harnesses in my old track Miata and liked them better than the 2" Schroth autocontrol I had in my old WRX for a while - also the Takata come in green!) but the Takata version doesn't have the detachable tail like the Schroth ones do. The more I think about it, the more I'm thinking I would want the autocontrol so that I have more freedom of movement when street driving.
Yes, thats the main driving point w/the Autocontrol. Freedom of upper torso movement when driving on the street or even a simple track day
Originally Posted by EVO8LTW
If you get in a frontal collision with the Schroth autocontrol on the street, will the harness allow your body to move forward into the airbag so you have a more gradual decel in the crash like a stock 3-point? Otherwise, you risk a neck injury in a hard crash since you won’t have a head/neck restraint on.
Its not really the Autocontrol that assists in a frontal type collision, its the ASM feature built into the right shoulder harness. Its the part w/the plastic sleeve. In a frontal, that sewn webbing detaches & unleashes approx 2 more inches of strap & allows some torso rotation that keeps your body from submarining under the lap belt. Heres the Vid on how its supposed to work
I don't know whether the Autocontrol would be better/worse/the same. I would think with the Autocontrol your upper body might have a little more range of motion up until the intertia reel kicks in, versus the same harness with just ASM where the range of motion is just belt stretch + the ASM section expanding.
Jan 29, 2022, 09:05 AM
) (edit: bolsters! that's the word)
