GSpeed's 2015 BRZ- SCCA Super Touring Build

[derek1ee]

Originally Posted by GSpeed

Not sure what you mean by the angle. This is a rear profile view, but it sounds like you're talking about the side profile view, in which case, yes, they're offset to the rear enough.



The plates are 2" x 3" and welded to the chassis. That's a total of 12 in² between the two of them, and the minimum size for a roll cage landing plate is 9 in² per NASA 15.6.14, for comparison's sake.



More reinforcement on the other side wouldn't help when they're fully welded to the chassis already. The shear area is already maximized. If you look at the total perimeter area of the reinforcement plates (≈20"), and the shear strength of mild steel (UTS*0.577), you'll see they'll have no problem holding in the weight of a driver, even at absolutely brutal deceleration rates.

Yea I was talking about the side view angle. I think it's recommended to have a 0-20 degree angle, with 20 being the preferred one. But I guess if you have slider and want to accommodate different drivers, it's better to shoot for the middle range so you don't go out of spec for very tall/ short drivers.

Re: plate: I was under the impression that where you mount the plate to is just sheet metal, and not structure. Thus even if the plate is big enough, what it is welded to isn't stronger enough?


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[GSpeed]

Sorry we haven't updated this thread lately. Our engineering staff has been working pretty hard on solving some of the overheating problems with the C7 Z06 on track.

http://www.corvetteforum.com/forums/...velopment.html

Yes, we'll be applying the same things to this BRZ once we get the Edelbrock blower on.

[DarkSunrise]

Originally Posted by GSpeed

Sorry we haven't updated this thread lately. Our engineering staff has been working pretty hard on solving some of the overheating problems with the C7 Z06 on track.

http://www.corvetteforum.com/forums/...velopment.html

Yes, we'll be applying the same things to this BRZ once we get the Edelbrock blower on.

Nice work on the C7Z. It still amazes me that GM released an $80k+ "track car" that wilts after a few laps in hot weather and considered that a finished product.

[GSpeed]

Right? Such a dumb problem for a modern car to have. But enough of them were sold, even with automatics, that it's worth our time to solve.

[Jonsey]

Originally Posted by GSpeed

Sorry we haven't updated this thread lately. Our engineering staff has been working pretty hard on solving some of the overheating problems with the C7 Z06 on track.

http://www.corvetteforum.com/forums/...velopment.html

Yes, we'll be applying the same things to this BRZ once we get the Edelbrock blower on.

That was a fun read. Thanks for sharing!

[GSpeed]

This weekend, we made a brace for the polycarbonate windshield that we're installing. We're documenting all of these so we can make more for customer cars in the future.



The bottom mounts to some existing holes in the frame:



The top has some extra holes drilled, and then recessed with flat head screws.



The owner of this car also has that mean black Viper GTS that we're getting ready for a race next month, so we're still working on this in our spare time, but it's moving along. Hoping to be on track this month.

Jake

[GSpeed]

Front windshield is going on today. Here's a close up of the nut-serts we're using to secure the windshield, in addition to some clips around the perimeter.



The rear window is drilled and should be installed by tomorrow morning.



A few more checks and a nut & bolt, and we're planning on being on track tomorrow after lunch for some initial shakedown. The car hasn't been on track since it's big off last year, so we're going to ease back into it and make sure everything's good. We haven't changed anything performance-wise, but it's now a fully caged racecar so lots of things have been taken off and re-installed.

Stay tuned!

Jake

[GSpeed]

Well, it's been almost a year since this car has been on track, but it's first track day was a success!



I didn't get any good video from the session; I need to relocate the camera. We also didn't get lap times, but that's my fault for not updating the new dash (long story) with the proper GPS files.

Here's a graph of temperatures throughout the session:



Oil and water look fine, and ambient temps were about 90°F. Check out that diff temp, though. Continuously climbing, and reached about 290°F by the end of the session. We're going to have to do something about that.

Here's something interesting, though. I've been doing a lot of research on oiling systems as we're starting to corner harder, and look at these pressure drops through hard corners:



That's Oil Pressure (light blue) and lateral acceleration (dark blue). You can see through the hard corners, there are times when oil pressure drops from around 45psi down to the 20s. That's not a good sign. Not that the motor's being damaged right NOW, but that behavior certainly isn't going to improve as cornering loads increase.

For comparison's sake, here's a shot of a car with a dry sump around the same track.



This car is cornering about 1.5G steady-state, and there's no pressure drops to be found. We're going to start looking into dry sump systems for this car. Subarus have a nasty tendency to spill oil into the outside head over about 1.3G or so, and we'll probably be in that range once we switch over to Hoosiers (which are sitting on the shelf).

We also suspect the transmission fluid is getting pretty toasty for a long session, too. We've got some new sensors on the way (for the trans, and to replace that erratic diff temp reading shown above) that should help figure out exactly what's going on. We know there are reports of people chewing up gears, but if that's because fluid temps are high, there are easier solutions than new gearstacks.

There's also still some weird behavior going on with the rear shocks. We found an issue with low gas pressure causing cavitation that KW supposedly fixed, but we may have to put them on the dyno again and see what's going on.

Over the next week or two we'll be addressing all those issues, as well as doing a new setup on the car (just because he went off hard last summer, and to re-balance the car with the cage). Once that's done, Dave will see how fast it'll go around the 1.7 CCW for comparison's sake, and then we'll start adding the really fun parts.

Jake

[GSpeed]

We did a full setup on the car to check everything out. First time it's had an alignment since before the big off last summer, so it's worth going over everything in detail.

Here's a fun fact. Before the cage, in total stock trim, the car weighed 2917 pounds. That's with full interior, almost full tank of gas, and 200 lbs of ballast in the driver's seat.

Now, with the interior removed, a full cage, fire system, lexan windshield, and racing seats, the car weighs in at 2859 lbs. That's right, the car's 58 pounds lighter than a stock car now. Really shows you how heavy the stock seats and interior can be, since the roll cage is at least 150 lbs of steel.

[GSpeed]

So here's why everyone says the JDM AC Delete parts are trash. Just ordered the parts, and put one together. Fully tightened down, the pulley has 0.034" of play, axially, at the perimeter.

Looks like it's be fairly simple to make a dual-bearing pulley that uses the OEM casting, which is the majority of the cost in other aftermarket units.

[mrk1]

Originally Posted by GSpeed

So here's why everyone says the JDM AC Delete parts are trash. Just ordered the parts, and put one together. Fully tightened down, the pulley has 0.034" of play, axially, at the perimeter.

Looks like it's be fairly simple to make a dual-bearing pulley that uses the OEM casting, which is the majority of the cost in other aftermarket units.

I'd be very interested in a pulley, I have one of these deletes.

[Lonewolf]

@GSpeed

I haven't kept up with your development lately, but do you still need another FRS/BRZ for roll cage development, or did the black car with the poly windshield already fill that need?

[M1K3]

Originally Posted by GSpeed

So here's why everyone says the JDM AC Delete parts are trash. Just ordered the parts, and put one together. Fully tightened down, the pulley has 0.034" of play, axially, at the perimeter.

Looks like it's be fairly simple to make a dual-bearing pulley that uses the OEM casting, which is the majority of the cost in other aftermarket units.

If you make one I'll take one!

[GSpeed]

Originally Posted by Lonewolf

@GSpeed

I haven't kept up with your development lately, but do you still need another FRS/BRZ for roll cage development, or did the black car with the poly windshield already fill that need?

We need another car to use for installation instructions. We'd be willing to offer discounted labor for the install.

Originally Posted by M1K3

If you make one I'll take one!

Great! Shouldn't be too expensive, I'll try and get some quotes this week. Got it mostly designed last week.

Jake