GSpeed's 2015 BRZ- SCCA Super Touring Build

[Trac Toy]

Originally Posted by GSpeed

Yes, that's the gist of it. There are lots of variables like tires, power, outside temp, etc. but generally yes.

How many miles do you guys have on the car? Wondering if some of the heat issue is the gear set still seating?

There are lots of other shops and builds out there and while if I'm honest, I don't troll these forums and read every post, but this is the first time I've heard of there being a serious heat issue with the diff fluid.

Pretty open market at the moment for someone to develop a rear diff cover with some large cooling fins to aid the casual/frequent lapping day guy.

Or course much more frequent diff oil changes may just be required.

[Bramick]

Some diff heat temp conversation happening here https://www.facebook.com/groups/9117...9593174410635/

Other then fluids this was suggested as a possible aid/solution https://www.harrop.com.au/shop/diff-...-brz-toyota-86

[GSpeed]

Originally Posted by Trac Toy

How many miles do you guys have on the car? Wondering if some of the heat issue is the gear set still seating?

There are lots of other shops and builds out there and while if I'm honest, I don't troll these forums and read every post, but this is the first time I've heard of there being a serious heat issue with the diff fluid.

Pretty open market at the moment for someone to develop a rear diff cover with some large cooling fins to aid the casual/frequent lapping day guy.

Or course much more frequent diff oil changes may just be required.

There are a few diff covers on the market right now, and they're not selling well. In my opinion it's because A. people don't know how hot their diff is getting (or don't mind, since it's not causing problems) and B. They don't make a big enough difference in temperature. I'm predicting we'll need an external cooler to keep things happy. As previously mentioned, the reliability of a mechanically driven pump is worth the added complexity over an electric pump.

Originally Posted by Bramick

Some diff heat temp conversation happening here https://www.facebook.com/groups/9117...9593174410635/

Other then fluids this was suggested as a possible aid/solution https://www.harrop.com.au/shop/diff-...-brz-toyota-86

Thanks. I was the one that started that conversation. Glad to see people are reading it.

Jake

[GSpeed]

So based on the information above, we've decided we need to upgrade the shocks to be a serious track car. One of the first pieces of information you need to know when calculating a shock damping curve is the mass of your unsprung weight. Pretty simple process, just take parts off the car and weigh them!





(Before anyone asks, no, we won't be sharing the weights we're gathering. The only thing this information would be useful for would be building a shock curve, which means we'd only be helping our competitors, not the DIY'ers. Sorry in advance. We'll still try to share everything we can.)

Happy Thanksgiving!

[GSpeed]

I've updated the title of this thread to more accurately describe this build; the customer has decided to race this car in SCCA STU. Largely so he'll be able to pick races from each series' calendar, since he's already got a Viper built for NASA Super Unlimited. We'll still be using it for product development, but within the scope of preparing a car for SCCA road racing.

With the decision to run SCCA comes a much larger rulebook to meet. We're working on the aero at the moment, and SCCA has very specific rules for rear wings:

-Max chord of 8.5" (9.1.4.D.4.d)
-Max span of 48.25" (9.1.4.D.4.e)
-6" or more below the roofline (9.1.4.D.4.f)
-Can't extend behind the rear bumper (9.1.4.D.4.g)

However, there's an exemption for the 48" APR GTC-200 "SCCA Spec" that has a slightly larger chord than the rules would normally allow (8.75"). We decided to give it a shot and see how it looked. Man, was I disappointed. I know it's cheap, but it wasn't close to fitting well.

With the mounts at the outboard settings, here's how it sits on the trunk:





Okay, no big deal, we'll just use the inboard mount locations that will land more towards the middle of the trunk where it's flatter.



That's how the mounts fit up to the airfoil. That's not gonna work on a racecar.

Based on those two fitment issues, we're going to send it back. We'll put together some cost estimates for a wing from a "real" racecar wing manufacturer, and decide if it's worth running a wing at all. A 48" x 8" wing isn't going to produce a whole lot of downforce (especially at that mounting location) and it may not be worth the cost.

On a more positive note, the shocks have been ordered (Bilstein MDS) and should be here in the next few weeks. We spec'd a custom valving that puts more emphasis on low speed motion for better response, while allowing more "give" under high speed motion (digressive curve).

We'll have some more updates this week on the diff and trans coolers, too.

Oh yeah. We're going with a Dailey Engineering dry sump oil system on this car, so we'll have lots of updates about that too.

Jake

[philooo]

you said dry sump !!!! NICE !

[ajh88]

Nice build! Where are you guys getting your PFC pads? PFC 08/13 F/R still the trick? Have always heard they made a great pad but saw them more in the Euro crowd.

[GSpeed]

Originally Posted by ajh88

Nice build! Where are you guys getting your PFC pads? PFC 08/13 F/R still the trick? Have always heard they made a great pad but saw them more in the Euro crowd.

We're a PFC dealer, so we'd be happy to sell you some.

The 08/13 combo is great with stock calipers. They don't make that same compound for this AP Racing caliper, and we haven't figured out what compounds we like best yet for this setup.

[GSpeed]

Finally got around to removing the steering wheel lock today. More details here: http://www.ft86club.com/forums/showthread.php?p=2849071

[GSpeed]

Dry sump showed up early! The oil tank, breather, and such are still in the mail, but we may go ahead and start with figuring out how we're going to do the exhaust.

[GSpeed]

Bolted the pump up today to see what we're looking at. This is gonna be fun! Not sure how we're going to make room for everything, but we've thrown harder problems at our fabricator before.

[vgarcin]

Pics highlight very well that a custom header will be required.

[GSpeed]

The pump's back at Dailey Engineering right now to get the stages rearranged, we had an idea that might make exhaust packaging a little easier. In the mean time, let's modify the oil pump drive spacer to allow for the pump drive pulley.



First off, clamp in the mill and find center.



Scoot over a bit, and drill a hole.



Then open up that hole a little bit with a reamer.



Deburr your hole, because you're not a savage.



The fun part is getting the dowel out. I didn't have any solid carbide drill bits that could chew through it, so I shaved off the top 0.050" or so with a carbide end mill.



Still wasn't able to drill, so I machined it down to about 0.005" above the surface.



Next, chuck it up in the lathe and make sure it's centered. Six jaw chuck is a massive help here with the flats milled on the side.



Turn the nose down a smidge to make room for the dry sump pulley to index into the harmonic balancer.



Deburr, press in a longer dowel, and ta-da! Modified oil pump drive spacer.



You can see here what that accomplished. Dowel now sticks up to drive the oil pump pulley, and the centerbore is now recessed to allow for a second pulley.



There. Oil pump pulley mocked up. We'll throw it back in the car, updates to follow on the modifications necessary to the oil pump & front cover!

Jake

[kask2_6.0]

Super jealous of that dry sump! Any reason for modifying the stock pulley to fit a gilmer versus using the ATI super damper? Cost?