ImperiousRex's Greddy Turbocharged BRZ

[OICU812]

There's been talk of this new Excedy STG 2 clutch having no chatter and slightly heavier peddle feel over stock and suppositively very DD friendly. Is that accurate in your opinion??

[ImperiousRex]

Originally Posted by OICU812

There's been talk of this new Excedy STG 2 clutch having no chatter and slightly heavier peddle feel over stock and suppositively very DD friendly. Is that accurate in your opinion??

In general I would say yes. From a stop the clutch needs to be quickly eased into because of its tendency to grab but once the car is moving at all, it's very easy to use and on track it's very solid. The pedal feel is slightly heavier than stock but it's still pretty light compared to other clutch solutions.

I have one issue where sometimes it's difficult to get into 1st gear (at times it feels like the gate isn't fully open) but I also had this issue with the ACT clutch. Having said that though, my situation is a little different due to the engine/transmission mounts and LSD so my observations might be a little different than someone with a stock car.

[OICU812]

Originally Posted by ImperiousRex

In general I would say yes. From a stop the clutch needs to be quickly eased into because of its tendency to grab but once the car is moving at all, it's very easy to use and on track it's very solid. The pedal feel is slightly heavier than stock but it's still pretty light compared to other clutch solutions.

I have one issue where sometimes it's difficult to get into 1st gear (at times it feels like the gate isn't fully open) but I also had this issue with the ACT clutch. Having said that though, my situation is a little different due to the engine/transmission mounts and LSD so my observations might be a little different than someone with a stock car.

Ok and no chatter that you have observed as of yet?

[ImperiousRex]

Originally Posted by OICU812

Ok and no chatter that you have observed as of yet?

No chatter so far

[SmsAlSuwaidi]

I would recommend pushing your rad forward, it would help you a decent amount

[King Tut]

Originally Posted by ImperiousRex

So what you see here is the power on the first run when everything was cool and on a DynoJet vs. power after 6 runs at high rpm's. The whp in cool conditions again corroborate the Evasive numbers but the 40whp loss after 6 runs was eye opening. On track we suspect the car is losing even more power after multiple sessions and the main culprit appears to be the intake ambient temperature (IAT). As you can see there's a direct correlation in this graph:

Now keep in mind this is probably something that daily driven cars will never really experience. This type of heat soak is from sustained high RPMs for extended periods of time. On track this will be up to 20-25mins of 5-7k RPMs during the entire session. (Although in hot summer months this can happen more naturally.)

I would say that the fact that you lost a PSI of boost on the second run was more of a contributing factor to the power loss than the IATs. The dyno with fans blowing still isn't going to simulate the IATs that are going to occur on a race track though. I would like to see an EcuTek datalog from an entire 20 minute session.

[ImperiousRex]

Originally Posted by SmsAlSuwaidi

I would recommend pushing your rad forward, it would help you a decent amount

Thanks! Yeah that's something we're looking into when we put in the new radiator.

Originally Posted by King Tut

I would say that the fact that you lost a PSI of boost on the second run was more of a contributing factor to the power loss than the IATs. The dyno with fans blowing still isn't going to simulate the IATs that are going to occur on a race track though. I would like to see an EcuTek datalog from an entire 20 minute session.

Yeah, the multiple runs weren't meant to accurately depict track conditions (and I already admitted as much), it was just meant to build up heat in the engine bay and see what was happening with the power. We probably lose another 10-20whp on track depending on ambient temps.

The point about boost is valid though. The boost chart didn't taper off at higher rpm's so I had ruled out a boost leak but perhaps something else is going on regarding heat expansion with the piping inside the engine bay. We also had another FI FT86 on the dyno that day and the power loss was similar at those IAT ranges. I'm pretty sure the ECU is pulling timing at that heat range but we'll be back on track at the end of the month and I'll try to get the datalog for you then.

[King Tut]

Originally Posted by ImperiousRex

The point about boost is valid though. The boost chart didn't taper off at higher rpm's so I had ruled out a boost leak but perhaps something else is going on regarding heat expansion with the piping inside the engine bay. We also had another FI FT86 on the dyno that day and the power loss was similar at those IAT ranges. I'm pretty sure the ECU is pulling timing at that heat range but we'll be back on track at the end of the month and I'll try to get the datalog for you then.

Sounds good. An EcuTek datalog will tell you what timing the car is actually running. Are you just running off wastegate or are you using something for boost control? Normally a manual boost controller or a wastegate can be influenced by heat and produce different boost levels depending on temp.

[ImperiousRex]

Originally Posted by King Tut

Sounds good. An EcuTek datalog will tell you what timing the car is actually running. Are you just running off wastegate or are you using something for boost control? Normally a manual boost controller or a wastegate can be influenced by heat and produce different boost levels depending on temp.

No boost controller yet. It's just running off the wastegate.

Also after re-reading through my updates, I don't want to come off as demeaning the turbo kit in any way. The design comes with some inherent issues but overall the car has been pretty solid after many hard track days. I think it's a testament to Greddy's quality control and the issues are just giving us a clearer path to improve the car

[Cliu91]

How loud is that Greddy exhaust? I've had my eyes on it for a while. Will it draw too much attention? I DD my FRS.

[ImperiousRex]

Originally Posted by Cliu91

How loud is that Greddy exhaust? I've had my eyes on it for a while. Will it draw too much attention? I DD my FRS.

LOL you tell me

[ame="https://www.youtube.com/watch?v=qNLKubCqMhk"]Silent but Deadly turbo BRZ - YouTube[/ame]


But in all seriousness, I like the exhaust quite a bit. The 70mm diameter was a selling point but so were the silencers that it comes with (which are demonstrated in the video above). Certain tracks like Laguna Seca have a strict dB limit and I wanted to be sure that I had an option to quiet it down if I needed.

When I'm running a straight pipe and no silencers with the turbo kit however, the car gets loud inside the cabin. For some reason the noise doesn't travel very far from the car but it all seems to channel inward

[CSG Mike]

Originally Posted by King Tut

I would say that the fact that you lost a PSI of boost on the second run was more of a contributing factor to the power loss than the IATs. The dyno with fans blowing still isn't going to simulate the IATs that are going to occur on a race track though. I would like to see an EcuTek datalog from an entire 20 minute session.

PSI =/= Power.

There is a very weak correlation at best.

Lets dig into why this is. As the IAT gets hotter, it has a larger differential from ambient. The psi coming out of the turbine is the same, but because the IAT is hotter, the air is cooled more (relatively speaking) by the intercooler, causing a large pressure drop.

While the PSI is lower, the mass of air flow into the engine has not changed from before/after the intercooler. The absolute mass is lower, since the turbo itself is not able to pack as much air into the same amount of volume.

Remember, PSI is a pressure measurement, not a flow measurement.

If you look at datalogs, the heat soaking happens within the first outlap.

[Fresh86]

this build is so amazing

[Scracho]

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