heinzboehmer's 2002 Topaz 6MT Coupe

[Mike RT4]

Jan 2022

New wheels!

Got some 18s for the street, as the 19s were quite tiring on rough roads and I wanted less unsprung mass. Tires are PS4Ss (which were not easy to source).

Front: 18x8.5" ET35 Race Silver APEX EC-7 with 235/40/18
Rear: 18x9.5" ET22 Race Silver APEX EC-7 with 265/35/18

Car looks great and (most importantly) rides a looot better.



Here's some weight data:

Front (each):

• Wheel 18": 20.4 lbs
• Tire 18": 21.6 lbs
• Wheel + tire 18": 42.1 lbs
• Wheel + tire 19": 47.9 lbs

Rear (each):

• Wheel + tire 18": 47.1 lbs
• Wheel + tire 19": 53.0 lbs

Saved 5.8 lbs per corner up front and 5.9 lbs per corner in the rear. Not bad!

Buut of course something had to happen. Drove for probably 200 mi before finding this in my left rear tire:



Ridiculous. Got it patched and all is good.


At some point, I also took my rear seats out, so I took the opportunity to test fit the Slon wall with the VinceBar cups in place. Looks great, but unfortunately does not fit that well because of the extra material that the cups add. Cups will need some grinding, but that shouldn't be terrible.

Do you have any pictures of the final install of the Slon wall (as in were you able to grind away the required material on the cups)?

Did you also notice any difference/improvements after it was installed?

[heinzboehmer]

Las thing I did was to get started on my custom seat cushion.

I talked about making an L shaped cushion before, but ultimately decided to split it up. Still going to be L shaped, but just made out of two separate pieces. This is mostly so that the sewing is simpler, but will also make the whole thing a bit more adjustable.

Started off by sketching out a cut/sew plan:



Then came translating the drawing to real things. As mentioned before, I have no idea what I'm doing. So instead of messing around with (and probably ruining) fabric, I turned to the trusty CAD:



These are the final versions of the templates that I ended up using:



Transferred onto the fabric:



The machine I got access to was honestly pretty nuts. It could do a bunch of complicated stitches and all you had to do was press the foot control and make sure the fabric was going through straight. Here's some of the stitch patterns I messed around with:



Crazy.

I do realize that me being blown away by this machine is probably the equivalent of someone being blown away by one of my torque wrenches, but I still thought it was super cool. Didn't end up using the machine for anything other than regular straight stitches, though.

Here's the first stitch I did:




And the final product:




I stiched everything inside out so that there wouldn't be flaps of fabric on the outside and tried to follow how Cobra made their cushion. Images above also show how I left a ton of extra material on the sides. Did this so that I have some room to play with if I ever want to make this cushion any thicker.

Here's the thing turned right side out:




Velcro strips are a bit crooked, but whatever. Decided to use these thinner strips because I felt that the super thick ones that Cobra uses are waay too grippy.

Then moved on to cutting out the foam. Thought that using scissors would work out well, but quickly learned that this was not the case. Edges turned out super jagged and it was really hard to make sure the cuts were orthogonal to the face of the foam:



It's good enough for now, but I want to redo the foam with some sort of hot knife thing.

Lastly, the test fit:




It fits quite well! Pretty happy with how this turned out, especially considering that I was learning how to do all this as I went along. Seat looks kinda stupid with the Cobra cushion pushed all the way up like that, but whatever, it's a lot more comfortable on the street like this,.

Next step is to replace those towels with a cushion wrapped in fabric that matches the Cobra cushions. Ordered some dinamica samples, so will get to that once I know what matches best.

[heinzboehmer]

Knocked out a few things this weekend.

First off, I noticed that the fabric on my A pillar covers was starting to get pretty bunched up when I ran all my new dashcam wiring. Glued it back on with some 3M super 77.

Masked and adhesive applied. Put a ton on because that seemed to be what worked best when I was trying it out:




Turned out great! They look brand new now:




Then I trimmed the plastic trim pieces that come on the stock seat rails so that they would fit onto the new rails with the nogaro brackets.






For the first one, I almost exclusively used a dremel to do all the trimming, but I found out with the second one that it was quicker and just as good to use a box cutter. I did have to remove a decent amount of material, so I added some foam and zip ties to keep everything from rattling:






And here's the final product. Much nicer looking than the naked rail, in my eyes:



After that, I mounted the fire extinguisher under the driver's seat. Used to have it under the passenger's seat before getting the nogaros, but it's much harder to reach that seat now, so I decided to move it over.

I just zip tied the plastic clip that came with the extinguisher to the substrap bar:



Fits quite well in between the sides of the substrap bar. However, it does sit pretty far back, so it's not super easy to reach. I can reach it no problem with the three point belt on (even with it locked), but can't reach it with a buckled harness. There aren't any other good spots to mount it on, so I added some string that I can reach when strapped in with the harness:



String goes up and is held below the bottom cushion by a small piece of velcro:



Pretty happy with how it turned out. Extinguisher is super easy to retrieve and is kept above the lowest solid part of the seat rails (substrap bar), so there's no danger of it getting crushed when moving the seat back and forth.

[heinzboehmer]

Seats look great! Only people on the forum will know that you colored your seats in...lol

The inboard side mount bolts are the worst. I use B7 studs with loctite on the inboard side of the seat. Makes installing the seat no longer a chore. Eventually I want to remove the upholstery and screw in a bolt from the backside.

Thank you! I'm pretty sure I saw you say somewhere that you mounted your seats with studs and that gave me the idea to do this.

Definitely! Too bad it's been raining so much lately. You should also try my seat out (and vice versa), I'm pretty curious how the two differ.

I was lucky not to have discomfort (our torsos are likely different, but also maybe the wings on the Sparco are higher) - my shoulders are on the lower end of the wings, and don't really get pushed forward a whole lot. I think my height is similar to yours and recall it being quite disorienting as well, but I quickly grew to love it. I generally like sitting low, and usually push the seats in other cars to their lowest setting - not sure if the M3 seats are any lower than the non-M sport seats, but I felt they were always too high for a sports car. When I need to see the hood as reference for parking or pulling in/out of parking spots, I lean forwards off the seat back haha.

Yeah definitely have been getting used to the seating position, am liking it a lot more now. And yeah! Welcome to try out my seats whenever. Also curious to try yours out.

[timmo]

Hey man! It has been a while. Maybe we can do an occasional autox soonish

I'm pretty set on trying to make these seats work for me, as they're the only ones I know of that meet all my requirements (three point compatibility, harness compatibility, ease of ingress/egress, lightweight, etc.). The only others that might meet all of that are Pole Position ABEs, but I'm not fully sure how comfortable they would be on the street with the three point receptacle having to come through the seat. I think it'll be pretty much impossible to find a local car with those seats installed, so I'm going to try my best with the Nogaros. I've been messing around with them a good amount and I think I have a plan to make them comfortable on the street. But I'll definitely let you know if I find that I just don't well in the Nogaros.



Speaking of, I put a bunch of towels in the car and started driving around. Sat on them, put them behind me, put them besides me, basically tried every configuration I could think of to see if any made it more comfortable for me. I've learned two things (that kinda go completely against what I initially thought was uncomfortable about the seat):

1. I'm pretty confident now that the discomfort of sitting too low is 100% in my mind.
   1. It felt very disorienting to have such a drastic change in the driving experience of a car that I've become so used to. However, the more I drive it, the more I like the "racecar" feel. I still think I'm at the limit of too low because my eyes are only about 1-2" above the steering wheel, so any lower would significantly limit my visibility. But point is, I'm liking it more and more, so I'm pretty sure I'll get used to this.
2. The discomfort is exclusive to my shoulders
   1. The length of my torso puts my shoulders right at point where the "wings" of the seat extend the furthest out. This means that my shoulders get pushed forward a LOT, which becomes uncomfortable after driving for a while. If the radius of curvature of the "wings" were a bit larger, I wouldn't have any problem.

Since the discomfort is isolated to the shoulders, I should be able to solve the issues by modifying the seat so that my shoulders can sit a bit flatter. I initially thought that if I sat further up, my shoulders would move out of the most aggressive part of the "wings", but it turns out that I have to sit too far up for this, so that idea won't work. The thing I did find that worked was to add extra padding to the back of the seat. This pushes my entire torso far forward enough so that my shoulders can extend back before hitting the seat. Here's prototype number one:

Definitely! Too bad it's been raining so much lately. You should also try my seat out (and vice versa), I'm pretty curious how the two differ.

I was lucky not to have discomfort (our torsos are likely different, but also maybe the wings on the Sparco are higher) - my shoulders are on the lower end of the wings, and don't really get pushed forward a whole lot. I think my height is similar to yours and recall it being quite disorienting as well, but I quickly grew to love it. I generally like sitting low, and usually push the seats in other cars to their lowest setting - not sure if the M3 seats are any lower than the non-M sport seats, but I felt they were always too high for a sports car. When I need to see the hood as reference for parking or pulling in/out of parking spots, I lean forwards off the seat back haha.