Great work, Zak! Bad lines or not a lowly miata badgering GT350's is got tier. Great work! The cars you are competing with in that class is hilarious. Vette, gt350, MIATA. lol.

Also not sure if those are standard mustang GTs but we had a guy tracking one and it's fast. It's hard on consumables but the traction, braking, and laptimes all impressed me when I went for a ride along.

Heh, this made me curious so I had to go look up your and the GT350 TT3 forms in the compliance database. Now I'm wondering -- what's the -0.3 for "Modification of the OEM roof line/shape and/or windshield/frame removal"? Aftermarket hardtop?

Do you know if the 449 on the GT350 is detuned? For some reason I thought they were closer to 500 at the wheels.

BTW, are you planning on going to BW in April? I'm leaning strongly towards coming down for that one.

--Ian

Yo, thanks Nate! Yeah, admittedly I didn't really watch the footage beforehand. Guess I was so excited while driving that I didn't notice the car ahead was kinda all over the place on that lap. Their PB ended up being over a second faster in the video, so I think (hope) that they were all over the place because I was in their mirror lol. Regardless, don't care too much. Still a rush fighting for times all weekend haha.

Ian, I added the roofline modification factor due to the makeshift dovetail I added to the car. To be honest, I don't know if it actually qualifies for the modifier. I also don't think anyone would call me out if I didn't claim it, but I figured it'd be best to play it safe.

I'll have to ask her next event if the car's detuned. Never considered that. They make an advertised 526 horsepower at the crank stock for what that's worth, but the powerband is pretty peaky if I remember correctly, so that might bring the "average" whp figure down quite a bit for classification.

I'm in a weird spot with the car classification-wise already. I'm currently ~40whp under my max power limit. Tire classification rules for this year allow for more power in my tire class than last year. I'm running the car at about 300whp and it's doing fine, but I fear bumping power above 320 will take me into the danger zone for the stock trans and bottom end. If I were to build a forged motor and do a trans swap on this thing, I could probably get within spitting distance of 1st place, but I don't feel like the (very expensive) juice is worth the squeeze at the moment.

I'll 100% be at Buttonwillow in April. Signed up last week actually. It would be awesome to finally match a face to the name!

100% leave the car as-is or detune it for a different class if you wanted to go that route, imo! You've already thrashed 1 NC box and you are at a sweet spot stock motor and trans wise. If anything start looking for more weight reduction, I'm not sure what more you can do really, or how far down the racecar hole you wanna go even in that regard.

The car really is a sweet package right now and building cars for rulebooks can be frustrating when those rules change, or you just want to race with a different group.

Again, love what you are doing here and it still makes me want an NC

Oh yeah, the TT3 class endgame for this car isn't going anywhere haha. Our region's biggest classes are TT5 and TT3, and I certainly don't want to dish out the cash to run a car higher than TT3 class haha. TT4 would be a super fun class to race in (my max power limit would be around 250whp with current tires unless I added some ballast). Just aren't that many cars in class usually. We had 4 in TT4 this weekend and that's more than usual. At any rate, I'm going to keep the car as is for the long haul aside from gearing changes and some additional aero.

Housekeeping.

Started the week by swapping my street tires and pads back in. Found this in one of my rear tires. Could've picked it up driving back into my neighborhood or before the first session on Saturday lol. Bummer. Tire was still holding air, though. I patched the tire Tuesday as this set will likely be retired and used for street use.

https://cimg9.ibsrv.net/gimg/www.mia...2052aa304a.jpg

The brake ducts seem to have done their job. Recently, I've been pulling my DTC60 pads out after a race weekend and going "Damn, that much wear in two days!?" I was running shorter sessions this weekend due to the heat, but these pads basically look the same as when I put them in last week. I'll measure them for a before and after test at the next event.

https://cimg1.ibsrv.net/gimg/www.mia...60018b4550.jpg

Rotors are kind of another story. These have four days on them and are still getting some decent spider-webbing. I think it's less so than before. Usually after five days, the rotors would show cracks all the way to the edge and be ready for replacement. These might have two days left? Will have to see how long a fresh pair lasts with the ducts. Also only the outside face is showing stress fractures.

https://cimg9.ibsrv.net/gimg/www.mia...912b72a653.jpg

https://cimg0.ibsrv.net/gimg/www.mia...39edb822c1.jpg

I've been playing around with ideas for a turbo brace for a bit now. There aren't really many options to brace the turbine housing to the head or block as it sits on top of the manifold and space is tight. Making a brace from the block to one of the oil drain bolts would be nigh impossible, but I have a couple M10 threaded holes in the head that are currently unused. I cut up a cat converter bracket I had from a Bronco Sport, along with some random steel plate I had laying around, and mocked up a brace that would bolt the turbo to the head via the V-band stud. I think this is normally a no-no right? The bracket is thicker/stiffer than it looks and can't be flexed at all without tools. Don't know if it'd be stiff enough to take all the load off the v-band but I figured something like this would be cheap insurance to keep the turbo in place if the V-band fails. Thoughts? I haven't bolted it in yet as I'm waiting for some fine thread nuts with larger faces to arrive.

https://cimg7.ibsrv.net/gimg/www.mia...eece7a5d88.jpg

https://cimg6.ibsrv.net/gimg/www.mia...1fe21b0528.jpg

I'm not sure how I feel about that, to be honest. I'm not sure bracing the turbo at the vband is the right move since it already broke there once before. It could help, or make it worse, or nothing at all! Not that this helps you any, just starting the discussion.

Yo! Hell yeah, always appreciate you chiming in Nate. I?m mostly questioning whether bracing the turbo via the downpipe V-band is a good idea or not just due to putting additional stress on that v-band stud itself. FWIW, it?s that lower V-band connecting the turbo to the manifold that I?ve been having issues with. Figured having the upper brace might take some of the leverage off it.

Gonna have to play with it more next week. Have spent a lot of recent weekends in a row doing car stuff. Gonna switch it up and head north to Santa Cruz this weekend to ride mountain bikes with the boys :)

Can you support the turbo on the cold side? Lots of bolts there.

I've tried to picture some different ways to use the compressor housing bolts for bracing but I can't figure out any options that seem like they'd be stout enough. The only option that looks like it might work would be making a brace from the top compressor bolts to somewhere on the valve cover. Using the lower bolts seems like it'd be near impossible since you'd have to work around the manifold runners. I'll post some more detailed pics next week and see if anyone has some clever ideas.

I am not an engineer, nor am I very smart, and this was on a Volvo racecar, but I believe one of the reasons I had so many broken studs and hotside housings is the difference in heat expansion rates between the cast iron housings/ stainless wastegates and the hardware holding it together. I finally solved wastegate stud failures by matching stainless studs to my ATP stainless wastegate housing. Inconel was the only thing that would last between manifold and hotside, so i suspect the lack of expansion of the inconel eventually stressed the hot side flange causing failures.

I don't know if this speculation hurts or helps you. Racing is expensive and breaks everything.

I see, I forgot which V band you had broken on that thing. Makes sense that it's the inlet one.

I still think that's more likely to break your V band than anything else, but send it and see what happens! I know @emilio700 was playing with some turbo bracing using swaybar endlinks, but those were lower down and actually connected to the hotside of the turbo itself, IIRC. No idea if that was successful for them or not though.

I’m gonna get stickers of this made and slap ten of them on my car.

That’s actually great insight because I hadn’t considered the rate of expansion between the materials at play. Not much I can do about it, though since the turbine inlet and outlet are both v bands. I’ve seen companies that make stainless housings for this turbo but I still think the issue lies in it being a top mount with the turbo sitting at a slight angle on the manifold and only one v-band holding it on.

Veru small development but I realized today that the car converter outlet V-bands on those same Bronco Sports are 2.5” and look a bit more stout than your typical v-bands we’re used to seeing on here. Instead of the clamping surface being split into three sections, the entire circumference of the flanges is clamped down on and the clamp looks a little thicker overall. Gonna slap one on next week and see if it works, then bolt up the brace I made and see if that breaks as well.

https://cimg2.ibsrv.net/gimg/www.mia...e0a0dbf22.jpeg

Ignore the integrated gasket, that’ll get tossed.