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Track use seat and harness

2028 Views 11 Replies 6 Participants Last post by  ksgrimsr, 
ksgrimsr
Although the V8 seats have a reasonable waist bolster, the amount of overall support is not great for track use. At the track I run at there is a strech where I hit redline in 4th in turn 9 (long sweeping high-speed stretch) and in order to make the shift I have to brace my knee against the door so I can reach the shifter against the lateral forces. Also, with my helmet my head has a tendency to rattle against the sunroof (I often run with the top off although that's a little questionable for safety) so a slightly lower seat would be great.

So I'm looking to replace my seat and also install a proper harness to keep me cinched in place better.

Do folks here have experience with the Sparco Evo seat and whether it fits in the space allotted or any other racing seat that might be recommended? Is it a little lower than the stock seats so I can get better helmet clearance? Also, for a 5-point harness install if the group has recommendations for safe and secure installation and attachment I'd value the inputs.

Knut
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QuadCam
How do you sit in the esprit with a helmet anyway?
I had to remove the cushion underneath the seat just so my head wasn't rubbing against the headliner. Forget wearing a helmet in there! lol

on a side note, some guys have installed the Elise seats to get more room.
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Vulcan Grey
I went to Elise seats and gained several inches of leg and head room, can wear a large Bell M3 without touching the headliner. But I slide around in the Elise seats a bit on the track. They are also not compatible with a harness.

I'm not sure about the Sparco, I have sat in Corbeau in an Esprit V8 that gave more room and support.
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ksgrimsr
I haven't taken the rear window trim off yet in preparation for scoping the shoulder belt anchors for a track harness, but in looking at the exploded view parts diagrams it leaves the impression that the stock shoulder belt is anchored in the plywood firewall. It's not clear that it's connected to anything structural other than the plywood.

Is the stock shoulder belt indeed just anchored to the firewall plywood? Is that viewed as structurally sound enough to anchor the shoulder belts for a 5-point harness?

Knut
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Vulcan Grey
The plywood firewall is structural.

You could either use spreader plates on both side of the bulkhead, or try to connect a harness bar to the bars that go to the door striker plates.

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Sanj
The seatbelts are not bolted to the plywood, there is a steel crossbeam that reinforces the top edge of the bulkhead and provides the seatbelt mounts. This is in turn attached to the door striker posts. As long as your shoulder harness attachments go through the steel crossbeam you should be fine.
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ksgrimsr
Sanj said:
The seatbelts are not bolted to the plywood, there is a steel crossbeam that reinforces the top edge of the bulkhead and provides the seatbelt mounts. This is in turn attached to the door striker posts. As long as your shoulder harness attachments go through the steel crossbeam you should be fine.
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That sounds much better. I guess I should have taken some things apart and had a look myself before asking...

Knut
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Sanj
I can imagine that on a V8 it is pretty hard to see that beam, since it is under the little shelf below the rear window. If you remove the side rear window carpet shelves and look at the structures the seat belt reels are mounted to, you might get a better idea. The mounts are welded to the crossbeam, which is in turn screwed to the plywood.
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J
That rear beam connects to the striker pins which go through the door latch to the beams in each door. That transfers to the front scuttle beam through the door hinges and forms a metal cage surrounding the passenger and driver. You definitely do not want to attach to the plywood, go around the rear beam or fasten directly to it. The upper retractors are attached to an extension of that rear beam.
David Teitelbaum
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ksgrimsr
Hi guys,

Since I just finished installing my seat and harness I thought I'd followup with the group in case others might be considering a track-day seat.

The Sparco Evo seat will indeed fit in the Esprit cockpit, and the bolt holes on the mounting rails I used even line up with the holes already in the floor so you don't even have to drill new mounting holes. I used the longer aluminum mounting rails that Spacro sells and with those rails the frontmost hole in the front section and the second to front hole in the rear section line up with the holes in the floor when the seat is pressed against the rear bulkhead.

There are several sizes of the Evo seat and I bought the plain Evo which is considered a "medium" sized seat. I'm 6'2" 175lbs and 34" waist and the seat is nicely snug for me. If my butt gets bigger or hips widen I'm in trouble, but I'm planning on gaining my weight in my beer belly which should be ok. If the other Evo sizes have a wider bucket on the seat then some work might have to be done to shave the edges of the brackets off or something since on my install the brackets fit exactly into the cavity with no room for spare side to side.

I did make a few adjustments that others might benefit from. The first is that in order for the brackets to mount at the bottom most settings, the tops of the brackets begin to interfere with the flare in the seat bottom. There is no need for the brackets to be so tall so I cut the top half of them off on the table saw (the brackets are aluminum and a good carbide blade cuts it fine). Also, when the rear mount is on the bottom most adjustment hole the seat is not quite as low as it could go (there is a recess in the floor of the car that you can take advantage of), so I drilled an additional lower adjustment hole in the brackets on either side to let me put the seat as low as possible.

When mounting I found that it sits lower and more securely if I remove the floor carpet under the seat and mount directly to the fiberglass floor. I use the floor mats to make the floor look finished for daily driving and will remove it and run with a bare floor on track days.

Merry Christmas.

Knut

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E5PR1T
Nice work, where did you mount the 5 point harness?

ksgrimsr said:
Hi guys,

Since I just finished installing my seat and harness I thought I'd followup with the group in case others might be considering a track-day seat.

The Sparco Evo seat will indeed fit in the Esprit cockpit, and the bolt holes on the mounting rails I used even line up with the holes already in the floor so you don't even have to drill new mounting holes. I used the longer aluminum mounting rails that Spacro sells and with those rails the frontmost hole in the front section and the second to front hole in the rear section line up with the holes in the floor when the seat is pressed against the rear bulkhead.

There are several sizes of the Evo seat and I bought the plain Evo which is considered a "medium" sized seat. I'm 6'2" 175lbs and 34" waist and the seat is nicely snug for me. If my butt gets bigger or hips widen I'm in trouble, but I'm planning on gaining my weight in my beer belly which should be ok. If the other Evo sizes have a wider bucket on the seat then some work might have to be done to shave the edges of the brackets off or something since on my install the brackets fit exactly into the cavity with no room for spare side to side.

I did make a few adjustments that others might benefit from. The first is that in order for the brackets to mount at the bottom most settings, the tops of the brackets begin to interfere with the flare in the seat bottom. There is no need for the brackets to be so tall so I cut the top half of them off on the table saw (the brackets are aluminum and a good carbide blade cuts it fine). Also, when the rear mount is on the bottom most adjustment hole the seat is not quite as low as it could go (there is a recess in the floor of the car that you can take advantage of), so I drilled an additional lower adjustment hole in the brackets on either side to let me put the seat as low as possible.

When mounting I found that it sits lower and more securely if I remove the floor carpet under the seat and mount directly to the fiberglass floor. I use the floor mats to make the floor look finished for daily driving and will remove it and run with a bare floor on track days.

Merry Christmas.

Knut
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ksgrimsr
E5PR1T said:
Nice work, where did you mount the 5 point harness?
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Ahhhh. The harness was much more interesting to get right than the seat since the seat only holds your butt.

The lap belts are easy and they attach to the same mounts as the standard seatbelts. You might notice I left the stock belts in place for daily use as it's more convenient to have the standard setup with the shoulderbelt that has some movement so you can reach the door to close it :)

For the lap belts you do have to use a sleeve or bearing spacer for the harness fixing so you have some movement at the end (just like the stock harness fixings do).

For the submarine belt there is not a good fixing point since the submarine belt normally attaches to the floor but the floor is not structural. I fabricated a spreading bar of 3/16" steel that affixed to the underside of the tub and attached it with several fasteners so it would have to tear the entire floor out before it gives. With the lap belt cinched low and tight and the fixed back seet keeping you upright, it would be a really bad day for that to fail.

The most interesting to deal with was the shoulder belts. The rear bulkhead beam is too low to directly attach to since the mount points must be even with or above the top of the shoulders to prevent spinal compression.

I sent the shoulder belt mount bolts (again with bearing spacers) through the bulkhead at the proper height under the rear window trim piece. The bulkhead is about 2 inches thick there, but I don't consider that to be properly structural for a safety harness. So on the backside I again fabricated and attached some spreader plates that run down to the bulkhead beam with a slight angle bent into the plate to follow the shape of the bulkhead in the engine bay and then bolted through the structural beam back through at that point.

I tapped the spreader plates and secured them to the bulkhead to make them captive for convenience and then secured the bolts with a jamp nut (which was also a nyloc since I happened to have that on hand). The configuration is conceptually similar to running the harness belts through a slit at the righ theight and then down to the beam, but instead it is fastened by a bolt to a strap (spreading plate) that attaches to the structural beam. Difficult to explain with words, but I think you get the idea.

With the rigidity of the steup I'll be investing in a HANS device since the only thing that has much give is the neck.

Knut
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