STX setup sharing thread (2021)

[cjd]

Originally Posted by Breezio

Just reviewed my data, 56mph, barely touching 57mph at 7500 rpm.

Yeah, I run out of tire even on 255 locally and revving to 7950. Kissing 60mph. However fewer courses where I am on the rev limiter for a bit where shifting isn't worth it. Is it faster on255? Who knows. But the net gearing is similar to the 13-16 and I'm not fast or consistent enough to be a great metric anyway.
Also, they were available...

[Breezio]

Originally Posted by renfield90

If there is even one or two big digs (so all other courses), you get destroyed by everyone on 245s. Generally speaking our cars are thrust-limited coming out of digs, not traction-limited, and you are reducing thrust.

Bottom line is wider rubber should help in theory, but the gearing changes add a course dependency factor that is much larger than any extra grip you might get.

Little bit of anecdotal information. A friend of mine has a '14 BRZ, we are both STX prepped (mine is a '17)
He has a better tune, dyno'd both cars same day same dyno, his makes 19HP more.
His car weighs 95 lbs. less then mine.
He runs 245's, I run 255's.

We did a 1st and 2nd gear pull. cars were practically dead even.

[steverife]

I've only tried the 245's.

I'm not sure how much of a difference the gearing actually makes. If you plug all the numbers in a gearing calculator, the 245 car is at 2500 rpms at the same speed where the 255 cars are at 2470 rpms. And I could very well see the wider tire keeping you bit higher in the power band.

With that said, the 255 is at least a lb heavier and I think that is a bit of a deal. And the 245 probably feels better.

Originally Posted by Breezio

Little bit of anecdotal information. A friend of mine has a '14 BRZ, we are both STX prepped (mine is a '17)
He has a better tune, dyno'd both cars same day same dyno, his makes 19HP more.
His car weighs 95 lbs. less then mine.
He runs 245's, I run 255's.

We did a 1st and 2nd gear pull. cars were practically dead even.

What you would really need for a meaningful comparison is a pair of cars with the same final drive (so both 13-16 cars) doing a 2nd gear roll from a gps speed like 25mph.

[Breezio]

Originally Posted by steverife

What you would really need for a meaningful comparison is a pair of cars with the same final drive (so both 13-16 cars) doing a 2nd gear roll from a gps speed like 25mph.

I agree. My anecdote was more about how much of a difference that final drive makes and the 255's possibly being needed and not a detriment on the 17-20 cars. I should have made it more clear.

[RT-BRZ]

Originally Posted by Breezio

I agree. My anecdote was more about how much of a difference that final drive makes and the 255's possibly being needed and not a detriment on the 17-20 cars. I should have made it more clear.

I ran 245's in 2020 and switched to 255's in 2021 on my '13. I don't have the data in the same places that I can readily compare but what I did see is that I saw about 3-4 mph slower in the back stretch at Mid-Ohio with the 255's even though I added a tune and other mods that definitely give the car more power.

I have some drag racing background and I know that a 4.30 vs. a 4.10 rear gear combined with the impact of a tire that is 1/2" bigger in diameter would be consistent with what I've experienced.

[ka-t_240]

Anyone running Sparco Evo L seats? Looking for seats and sat in these in a ND this weekend and liked the fit.

Those with aftermarket seats, what are you doing for the seat belt?

[Molez93]

Originally Posted by ka-t_240

Anyone running Sparco Evo L seats? Looking for seats and sat in these in a ND this weekend and liked the fit.

Those with aftermarket seats, what are you doing for the seat belt?

Harness bar with sparco 5pt belts for driver and passenger.

[Kelse92]

In a perfect world, harness bar and belts. There’s safety compromises in using the stock belts, but that’s how I ran my previous car. Omp seats and stock belts. Seats on this car aren’t really worth any weight savings since the stock seats are about 25lbs, but the better fit (especially on track) is worth it

[Autoxer62]

From the weight reduction thread:

Driver Seat= 43.6 lbs.
Passenger Seat= 39.2 lbs.

So:
43.6 + 39.2 = 82.8
Legal seat is 25 pounds or 50 total, you could save up to 32.8 pounds with light enough seats.

[Kelse92]

Originally Posted by Autoxer62

From the weight reduction thread:

Driver Seat= 43.6 lbs.
Passenger Seat= 39.2 lbs.

So:
43.6 + 39.2 = 82.8
Legal seat is 25 pounds or 50 total, you could save up to 32.8 pounds with light enough seats.

Is this off a heated seat car? The non-heated ones I don't think weigh that much. We weighed one we pulled from a friends car a while back, so maybe my memory is fuzzy, but I don't remember them being that heavy.

[RT-BRZ]

Stupid question; can you swap a '17-'20 rear diff into the '13-'16 and still be legal for STX?

[strat61caster]

Originally Posted by RT-BRZ

Stupid question; can you swap a '17-'20 rear diff into the '13-'16 and still be legal for STX?

You have to change the final drive to match the '13-'16 cars, but the LSD unit itself is open to being changed per ST* rules.

I don't believe there was any design change to the LSD though so only makes sense to source a lower mileage unit.

[Autoxer62]

Originally Posted by Kelse92

Is this off a heated seat car? The non-heated ones I don't think weigh that much. We weighed one we pulled from a friends car a while back, so maybe my memory is fuzzy, but I don't remember them being that heavy.

It doesn't say, at least in the summary, you could look through the thread to see if the exact year/model info is there. However, the heater grid is just some wiring, there won't be that much weight difference. I've swapped a fair number of seats over the years, and folding seats almost always weigh 35 to 45 pounds. The combination of OEM durability requirements and the added weight of the hinge mechanism gets you up to that unless they did something extreme to keep the weight off.

[Autoxer62]

Looking at the pile of parts, before I mess something up I've got a question on the Diftech bushings for the SPC control arms:

Are these the "burn out the rubber and leave the shell behind" kind?
Or the "press out the whole shell plus bushing" kind?

Most of the poly bushings I've dealt with are the "burn out" kind, thus the question.