Pure Motorsport: JDL Turbo BRZ Track Build

[gramicci101]

I think Evasive Motorsports' Pikes Peak car was turbo as well, but that's really a BRZ in shape only.

[DarkSunrise]

How much power is @ImperiousRex putting down now with his Greddy kit? I was under the impression he was near 300 whp and tracking fairly reliably after cooling mods.

[ImperiousRex]

Originally Posted by gramicci101

I think Evasive Motorsports' Pikes Peak car was turbo as well, but that's really a BRZ in shape only.

Evasive's car is running a modified HKS Supercharger set up.

Originally Posted by DarkSunrise

How much power is @ImperiousRex putting down now with his Greddy kit? I was under the impression he was near 300 whp and tracking fairly reliably after cooling mods.

I make 300whp on a dynapak with 100 octane (270 on a mustang) but the car still heat soaks fairly quickly. In CA winter conditions we get to use more of the power but during the summers, we lose about 50-70whp after a few sessions.

[DarkSunrise]

Originally Posted by ImperiousRex

I make 300whp on a dynapak with 100 octane (270 on a mustang) but the car still heat soaks fairly quickly. In CA winter conditions we get to use more of the power but during the summers, we lose about 50-70whp after a few sessions.

That's quite a lot of power loss. Any ideas left on how to prevent the heat soak, or are you content where it is now?

[ImperiousRex]

Originally Posted by DarkSunrise

That's quite a lot of power loss. Any ideas left on how to prevent the heat soak, or are you content where it is now?

It's just something I live with for now. My car is primarily used for time attack so I concentrate on getting my fastest laps early and on competition days I only use the car to set down a qualifying lap for pregrid and keep it cool until competition sessions. If the car were used for endurance or W2W racing, it would be an issue.

The heat soak effect is mainly just from the intake air temp getting too high so ideally you want to heat shield the intake piping, coat everything that generates heat and shroud all air movement so that the heat dissipates as efficiently out of the engine bay as possible. With an FI set up, I think a good vented hood is necessary.

[ATL BRZ]

Since the extra mechanical grip is now allowing a lot of exhaust movement as evidenced here:



I just ordered a kit of Torque Solutions 75A durometer 12mm exhaust hangers to help keep my new catback secured on track.

[icebär]

That rear view picture from the racetrack is just awesome!!!
Love the diffusor, so sad it isn't allowed here...

[King Tut]

I can see those helping up and down motion, but I don't know about it helping your side to side motion. I liked the idea one guy had to just put some C or E clips on the exhaust hanger to stop the side to side motion. My other solution would be to drill a hole and just use a cotter pin.

[smbstyle]

Originally Posted by King Tut

I can see those helping up and down motion, but I don't know about it helping your side to side motion. I liked the idea one guy had to just put some C or E clips on the exhaust hanger to stop the side to side motion. My other solution would be to drill a hole and just use a cotter pin.

Yeah, the C clips definitely help, but the real issue is the OEM rubber hangers get mushy when they get hot, and with enough lateral load, they will pop off. When the track cleared, the safety crew and I got underneath and literally just slid the hangers back on like it was nothing; when initially installing it I almost broke my fingers putting so much pressure just to try and get the hangers on.

[gramicci101]

Diff bushing inserts are cake, just remember to support the diff when you take out the front bolts or it'll try to escape.

Shift springs are pretty easy, you might just need to get creative with your extension and u-joint combination on the passenger side. I put the 27mm socket, a u-joint, and a 1/2-3/8 adapter on the bolt once it was started, then snaked two 6" extensions up on the passenger side of the exhaust pipe, and it worked just fine without having to move the exhaust. Have some isopropyl alcohol or something to clean loctite off the threads.

The bushings and springs make a HUGE difference. There's very little slop left in the drivetrain, and the shifter feels very solid and defined.

[ATL BRZ]

Originally Posted by gramicci101

The bushings and springs make a HUGE difference. There's very little slop left in the drivetrain, and the shifter feels very solid and defined.

I think I'm more excited about those two things than I am about the catback to be honest, lol

[gramicci101]

Originally Posted by ATL BRZ

I think I'm more excited about those two things than I am about the catback to be honest, lol

I did the diff bushing inserts, the springs, a transmission mount insert, and a shifter bushing at the same time when I changed my fluid to better stuff. It was really a night and day difference. Now when I shift, there's no more floppy clunk from the rear end and everything isn't heaving around randomly. I used to be able to go on and off gas while in first and feel the transmission move around through the shifter; it doesn't do that anymore. It's amazing the difference that can be made for about $150 or so.

All I need to do is engine mounts and I'll have the drivetrain locked down. I'm not going to do rear subframe inserts because I've heard that they create a lot of additional noise.

[ATL BRZ]

Originally Posted by gramicci101

All I need to do is engine mounts and I'll have the drivetrain locked down. I'm not going to do rear subframe inserts because I've heard that they create a lot of additional noise.

I have the subframe mounts now and didn't notice any noise, just way less slop on corner exit. I've heard the transmission insert is where the most noise comes from, but any combonation of the three (diff/trans/subframe) will contribute to some addtional NVH. Im sticking with poly bushings and avoiding the solid braces which I've read can cause some nasty vibration under deceleration when paried with other driveline stiffeners.

[gramicci101]

I might have to give them a try then, they're not too expensive. I'm a firm believer in the power turning the wheels, not just squishing bushings.

The trans bushing does give you a little noise, but it's worth it. And you can only really hear it when you're puttering around in 1st. Once you get on it or if you have the radio going, you can't hear it.