Charper732

Graphs like this one confuse me. Do you have one of where the torque is accurate to the rpm? What was the limiting factor? Any plans to max the turbo out?

DavidNJ

First decision: what fuel. With E85 or C85+ you can run lots of boost. WIth pump gas not so much.

Second decision: how much are you spending? There is a little variation in the cost of the turbo pieces (turbo, manifold, wastegates, intercooler, piping, etc.) but lots of variation on the long block. Are you an engine builder with the tools or do you farm that out? In any event, a built E85 motor can handle more boost. A built pump gas motor can use low-compression pistons (under 9:1) to allow higher boost levels. A built cylinder head will allow more revs. A built engine also provides the option of increased displacement with an overbore (89mm is common on a sleeved engine) and increased stroke (97mm seems common, but ask the engine builder)

With those decisions made, there are a variety of calculators or the underlying equations on the Internet to calculate the airflow required and a specific pressure ratio. This is key...the choke line on a compressor map typically has a significant positive slope especially at lower pressure ratios.

If you are running pump gas with basically a stock long block running at or near the stock rev limit, as mentioned already the G25-660 is probably the best choice.You are looking at pressure ratios under 2 and probably around 400whp or less. If the pump gas engine is 2.4L with 8.5:1 compression ratio running 10k rpm at 16psi boost, it is well over 600hp and the G25-660 would be out of its league. You would also be at power levels that are challenging for the stock drivetrain. I'd probably look at the new for 2019 EFR 8474.

E85? Much higher hp is possible. Bigger budget because of the drivetrain changes. I recommend reading @Charper732 's build thread for insights. He already posted on this thread. @hatrickstu also has a build thread of a car he drives on the street. However, he uses C90 and has hit 960hp @ 42psi boost. Enough to earn him several third-party videos. He simply ran out of turbo, leaving maybe 200hp on the table.

Sarén-Swe

664whp/623nm.

I want to drive some this year and dont blow up the engine. Car is for trackdays and timeattack. Still havent changed the rear end...blew the gearbox up in the end of last season(470whp). So the gearbox is upgraded. Everything else supports around 1000hk.


Might max the turbo in the end of this season. First tune the wg was to small, 2.5bar gave 650whp@7k rpm.

DavidNJ

What fuel were you using? Why did you stop at 29psi boost? It looked like a fall-off in VE at the top which was still a fairly low engine speed for an F22. What cam was used and what head work had been done? The GTX3582 should have still had more to deliver (over 70lb/min) according to its compressor map. And E85 brings some additional oxygen to the party.

Sarén-Swe

I'm running e85. Its a f20. It has more to deliver..i just stopped at 29psi. Enough hk's for now. Stock rear end with square 295..

Head is built with retainers and springs. Stock f20 cams.

DavidNJ

Not an expert, but it looked to me as if it ran out of breath above 7000-7500rpm. That could be backpressure. It could be a need for more cam or different cam timing (less overlap, a bigger problem with high backpressure). A good porting also improves VE. Do other OEM 2.0L turbos also show that drop off in torque?

Charper732

You are going autoX with that? Holy hell. Lol that thing comes on like a freight train. I would think it would be hard to control in anything other than straight line. Did you consider using a smaller a/r housing to get spool time a bit better/ a more manageable tq curve?

Curious on your trans upgrade..thats the most expensive part. Keep us updated. Really interested in how the power curve changes as you push it

Sarén-Swe

Went with Samsonas, 6speed sequential.

Got around 3,5k rpm with full boost. Can still rev some more..but time will tell So Will probably raise the rev limit if needed.

Charper732

holeeee shieet. The cost of that trans is what I paid for my car when I bought it stock...lol. That thing has got to be sick as hell

DavidNJ

This begs the question: what ECU are you using? Some ECUs will enable clutchless WOT upshifts and clutchless auto-blip downshifts.

Are you going to a Ford 8.8in rear?