Tracked Emira's Tillet seats & 6-point harness upgrade

[geoffbland]

Are these as safe as a harness bar? (in terms of submarining). Where do the bottom straps mount to?

How would a harness bar affect or prevent submarining? Only the shoulder straps are attached to the harness bar aren't they and it is just the crotch straps that stop submarining? What am I missing here - I'd like to understand this?

 

[Steve Tillett]

Submarining is improved by the crotch strap. But with Tillett seats only requiring thin padding, you are unlikely to slide forward and under the belts. A bigger area to concentrate on is to try and minimise any deflection in the belt from the mount point to the body. You do not want it tightening onto the seat and pulling on the shell.
I would also say that the hip points should not be too far back. Although with a six point you have a restriction in an upward movement, it is important to restrict this as much as possible. So make sure the hip belt points are not mounted too far back. They should pull downwards and to the rear, as you will see on the mounting points of OEM belts. But if the mounts points come from behind the seat, it will allow the body to travel upward in a backwards into the tyre wall type crash. Especially if the crotch mount point is not directly below the crotch hole and the belts loop backwards underneath toward the rear of the seat.

 

[lynchy73]

I’ve been digging into harness mounting and harness angles. There are different rules for different organisations it seems.

This page has some information: https://track-first.com/fia-8855-20...BUllXnYpMzV4DYbJWhrXgwWwNbdMuP3p6nwkM0s-PdUVa

Attached is a diagram. I believe the 4 mounts behind the seat (that I personally used) fall within these guidelines. Other organisations have different guideline angles on the crotch strap it seems.

 

[lynchy73]

Submarining is improved by the crotch strap. But with Tillett seats only requiring thin padding, you are unlikely to slide forward and under the belts. A bigger area to concentrate on is to try and minimise any deflection in the belt from the mount point to the body. You do not want it tightening onto the seat and pulling on the shell.
I would also say that the hip points should not be too far back. Although with a six point you have a restriction in an upward movement, it is important to restrict this as much as possible. So make sure the hip belt points are not mounted too far back. They should pull downwards and to the rear, as you will see on the mounting points of OEM belts. But if the mounts points come from behind the seat, it will allow the body to travel upward in a backwards into the tyre wall type crash. Especially if the crotch mount point is not directly below the crotch hole and the belts loop backwards underneath toward the rear of the seat.

@Steve Tillett or anyone with a deeper knowledge of this subject than me.

For info here is some more harness guidance, but I suspect they also assume the seat is bolted down, not on a slider?

https://www.motorsportuk.org/wp-content/uploads/2020/09/harnessguidance02.04.19.pdf

The below arrangement seems to be more typical.

However, for me personally, I had to make the clip in harness that I had in my hands work (can’t get bolt in Schroth harness here, would be special order and take weeks to get them), using parts I could get fairly quickly. Happy for anyone that knows more about this subject than me, to offer advice. I might have some options to move the crotch strap forward, underneath the seat. I can see how having straps both forward and behind will keep a slider mounted seat in place, for both forward and reverse impacts.

@Steve Tillett are these sliders designed to stay in position on impact, or can they move forward/backwards?

 

[crashprash]

i have a harness bar, only the lap and crotch belts are fitted to the hooks on the floor (crotch to the 2 inner hooks, lap belts to the outer hooks). I looked at the FIA harness regulations and the angles look fine for all the belts (US regs differ on the crotch belt angles). All things considered, i think this works and it mounts everything to the body, rather than the seat. The floor mounted hooks are a common product intended for the GR86, that happens to match up to the Emira bolt spacing.

View attachment 81912

Link to the floor mounts?

 

[lynchy73]

Link to the floor mounts?

I bought them in China from Taobao and they were not expensive. They are intended for the GR86. They seem to be a pretty common part and that is a popular car. I'm sure you can find them if with a google search. Emira bolt spacing is 40.5cm and these brackets have slots that cover that without mods. Here is a link for the same part, not sure it will work:

【淘宝】7天无理由退货 https://e.tb.cn/h.R1FZBz62F14fxmj?tk=fkwa5HAQHPY HU071 「现货丰田86斯巴鲁BRZ四点式改装安全带支架 赛车座椅滑轨固定支架」
点击链接直接打开 或者 淘宝搜索直接打开

 

[mr.suntorytime]

Submarining is improved by the crotch strap. But with Tillett seats only requiring thin padding, you are unlikely to slide forward and under the belts. A bigger area to concentrate on is to try and minimise any deflection in the belt from the mount point to the body. You do not want it tightening onto the seat and pulling on the shell.
I would also say that the hip points should not be too far back. Although with a six point you have a restriction in an upward movement, it is important to restrict this as much as possible. So make sure the hip belt points are not mounted too far back. They should pull downwards and to the rear, as you will see on the mounting points of OEM belts. But if the mounts points come from behind the seat, it will allow the body to travel upward in a backwards into the tyre wall type crash. Especially if the crotch mount point is not directly below the crotch hole and the belts loop backwards underneath toward the rear of the seat.

Can this launch me though the roof like an ejecto seat?

 

[Steve Tillett]

@Steve Tillett or anyone with a deeper knowledge of this subject than me.

For info here is some more harness guidance, but I suspect they also assume the seat is bolted down, not on a slider?

https://www.motorsportuk.org/wp-content/uploads/2020/09/harnessguidance02.04.19.pdf

The below arrangement seems to be more typical.
View attachment 81973
However, for me personally, I had to make the clip in harness that I had in my hands work (can’t get bolt in Schroth harness here, would be special order and take weeks to get them), using parts I could get fairly quickly. Happy for anyone that knows more about this subject than me, to offer advice. I might have some options to move the crotch strap forward, underneath the seat. I can see how having straps both forward and behind will keep a slider mounted seat in place, for both forward and reverse impacts.

@Steve Tillett are these sliders designed to stay in position on impact, or can they move forward/backwards?

No road car based slider is meant for competition. We advise solid fix for competition.
Many years ago we tested some single side locking ones to see what would happen in a FiA crash and they exploded. That’s when we went to the handle locking both sides and our current ones are more than doubled the kg rating.
That being said nearly every performance car in the world is running around with similar sliders.

 

[Steve Tillett]

Can this launch me though the roof like an ejecto seat?

Not with a crotch strap. But people should realise the limitations of a four point, which can allow the body to move upwards too much in a rear end crash. Especially if the hip straps track backwards almost horizontally.

 

[lynchy73]

Got my harness bar fabricated into a half cage. Had a track day at the shanghai F1 track on Saturday. Recently upgraded my rear discs/pads and fitted 265/35/20 on 9” wide front and 305/30/20 on 11” Wide rears, Sailun PT01 tyre and they are great with -3.5/-3degs front/rear camber. Car performed really

well, we’re finally getting there with the mods

 

[lynchy73]

My Zestek steering wheel is now (mostly) working. The small, round carbon wheel with slim rim feels great (also from Zestek, but it’s a standard fitting). I’m not a fan of the off center, funny shaped standard wheel TBH. The new wheel combined with the Tillett seats and Harness feels proper race car.

I believe my car is 1 of the first Emira to have this latest version Zestek wheel hub. Additional integration to the car is still under development, but basic stuff is working most of the time. It’s quick release too. That might help ingress/egress, it’s quite challenging with the Tillett’s for this not so young guy…

 

[Savanna7]

I love the size and shape of the wheel, especially with the quick disconnect! I'm not sure if I love the lights. Maybe they seem brighter due to the photo? Are they dimmable?

 

[Beachbum]

What do all the buttons and lights do on the steering wheel?
Given you have changed/upgraded the steering wheel, have you upgraded the rack too?

 

[lynchy73]

I love the size and shape of the wheel, especially with the quick disconnect! I'm not sure if I love the lights. Maybe they seem brighter due to the photo? Are they dimmable?

For sure, the lights are way too bright ATM (worse in pics than reality I think). Every button is adjustable for colour and the overall brightness is adjustable, but I’m not too familiar with the setup yet. I will be backing off the brightness ASAP.

 

[lynchy73]

What do all the buttons and lights do on the steering wheel?
Given you have changed/upgraded the steering wheel, have you upgraded the rack too?

ATM the wheel just does the same functions as the factory wheel. You assign each function to whatever button, scroll wheel or toggle you want.

Later will have the rpm indicator (fully configurable) and can display temps or whatever from OBD data (there is an OBD dongle that talks to the wheel). Later should even be able to select the driving mode or other stuff, via an additional module that talks with the wheel, even indicators or flash lights from the wheel.

Unfortunately there are some teething problems, but hopefully they get sorted soon. It has caused some issues with the indicator/wiper/lights module function (a unit which includes the stalks).

In contact with the developers, I’m somewhat of a guinea pig for the development.

 

[lynchy73]