[Irace86.2.0]

Originally Posted by CSG Mike

The turbo does not. The stuff I added beyond the kit gives me some control.

I don't have a "kill" mode. My wastegate effectively runs permanently closed, and the power i make is all i make.

A supercharger can also have any number of maps for various octanes and circumstances.

Originally Posted by CSG Mike

SC's bleed boost; TC's generally build less boost, for the type of control you're talking about.

I spool to 7 psi, rising to about 10.5 psi.

I'm effectively dead even with an Edelbrock or Harrop kit on a standard pulley + ethanol and tune.

Yes, I spent a lot more money to end up at a SC powerband. I can make a meatier powerband, and used to, but it just doesn't make sense to.

Originally Posted by CSG Mike

It's simple physics.

- small turbo, so small it's maxed out, and doesn't actually need a wastegate to run safely
- maxed out turbo = out of efficiency island, vs say, a TVS1320 which is in the meat of its powerband
- known data that on a FA20: Whether JRSC, Edelbrock, or TVS, on 91, they make the same power whether you're seeing 9psi or 12 psi

- to supplement my maxed out turbo, I also run a giant giant Garrett intercooler rated for more than double what I need, complete with ducting
- If you saw my pre-intercooler charge temps, you'd probably shit your pants

- I make no more power going higher than 7psi on a 91 octane map, due to diminishing returns on boost vs iat vs octane, so my 91 map peaks at 7 psi. My 91 map at 7 psi (or 10.5 psi if you want to get technical) makes roughly the same power as a JRSC/Edelbrock/Harrop on their standard pulleys.

You're welcome to extrapolate my power using videos.

Originally Posted by CSG Mike

Because with the current setup, I literally, cannot overboost. Stuck wastegate? no problem. Wastegate failure? no problem. My goal is reliability and sustainability, not pure output.

Enabling more power and/or efficiency is just a matter of swapping on a larger turbo, but why? I can't use any of that extra efficiency/overhead without going back into constantly-breaking-transmissions territory.

I don't care to total my car with a CD009 swap, and don't care to swap in a PPG gearset.

If I just want more power, there are other more powerful cars I can drive.


At the end of the day, I went turbo because I wanted to prove that a turbo setup can be done reliably. It just so happens a supercharger can put out just as much power at roughly half the cost.

Modern superchargers are far more efficient than I think you may give them credit for.

Again, I'm just trying to understand these statements.

A wastegate that is permanently closed is one that never opens, so it never allows exhaust gases to bypass the turbo's exhaust turbine. As such is the case, the turbo is free to flow as much air as it can, which will be a byproduct of how fast an engine can spin the exhaust turbine that will spin the compressor turbine, and how much air the compressor turbine can grab. That is a limit of the size of the fins, the speed of the fins and any offloading limits, so the size of the housing.

Considering the above, it sounds like you are saying the turbo is so small that even without a wastegate the turbo will not overboost on your setup, and what happens is boost rises fast to 7psi, but then it rises more slowly where it hits its limit at 10.5 psi before hitting redline or falling. Ok, so if that is the case, and we know other 2.0L platforms and 86's hit higher boost, while still using their wastegate to not overboost, what are you doing to keep your pressure down? The only answer I can think of is IATs being dramatically lower, but I don't think a giant FMIC would do it. I could be wrong.

Maybe you misspoke, and your wastegate is opening at a predetermined boost level of 7psi, which is where your wastegate spring is at, but you have an EBC tuned to bleed off boost from the vacuum line running to the wastegate, so you can slowly ramp up boost to a peak of 10.5 psi.

I'm curious. I would love to see someone remove the pressure line going from the turbo's compressor housing to the wastegate actuator, so the wastegate never opens and run this turbo to redline.