Precision has also released a turbine housing for the GT42-R that is open design. Next season when I replace my turbine housing for the third time, I will go with this and be done replacing cracked twin scroll housings.

 

To me a quick spooling turbo is worth it and the only reason I am going 2.3L and the only reason I am going twinscroll. I would love to see AMS and bushur get kits out there because right now there is only one kit on the market...

time attack/hillclimb car.

 

If I were building the ultimate car to drive in traffic without shifting any gears, I would build a stroker MIVEC motor with a stock turbo.

If I were building a road race / drag race car, I would build a stroker motor with cams and intake manifold that moved the VE of the motor to the rpm I would be operating the car in during those times. I would also have a turbo kit that was fully spooled by the time I got to those rpms.

You CAN have a turbo spool too early. The 20g is notorious for surging like crazy on the Evo. The object is to match your bolt ons and turbo kit to where you want to USE your power.

All of this talk is senseless anyway. Lets see some dyno charts of how much "better" the twin scroll is over a conventional style turbo and then we can hash it all out.

 

Yeah I agree, definitely want to see some dyno charts before I even think about plunking down my hard earned cash.

 

Just wait Ivan. If the twin scroll is successful, you guys will be making one, guaranteed. Check out the 240 Forum thread where the guy cut 2 seconds off his lap time just by changing to a twin scroll turbo of the same size.

As I said, if this is successful, you'll see all the big race shops making them

 

Can you define "successful"?

I would love to see the 240 test data. If his old turbo setup was so slow to spool that he was able to knock off 2 seconds by changing his setup, then his original setup was not right to begin with. How large was the track? Were the tests done on the same day? Was the header changed for the twin scroll? So many variables.

If you show me a reason to have full spool by 3000 rpms I will show that a down shift is a better option.

 

Too much shifting will slow you down around a circuit.

 

i disagree. for road race cars and autoX cars downshifting is not always an option.

ts gt35r + stroker would be the ultimate track car and a fun autoX car imo.

 

Come on Ivan, any time you can make the same power at less rpm, it's better. That's just common sense. You need to read up more on the alleged benefits. The spool up is just part of the improvement and is not the reason given by the 240 driver for the improvement in his track time. You can find the thread yourself and PM the guy. From what I can tell, he was pretty well known on the forum and a very regular track guy.

I'm still waiting to see some EVO results, but this definitely looks promising. If it wasn't beneficial, why would Subaru and Mitsubishi be doing it on OEM turbos? They've got a pretty big team of very educated and highly paid engineers working on these things.

 

If you are at 3000 rpms on a road course, you are in the WRONG GEAR!!! The only reasons I could see for that would be to LIMIT power to the wheels but I thought that is what your gas pedal was for???? or possibly in a long increasing radius turn that you do not want to shift in the middle of.

If you are at 3000 rpms in ANY gear you can down shift and take advantage of the torque multiplication of the GEARING and accelerate harder.

Adding TQ to an RPM area you hardly ever use is pointless. ESPECIALLY if it sacrifices TQ in an RPM band you CONSTANTLY use.

Your TQ should be highest in the rpm range you want to accelerate the HARDEST.

 

This is true if it does NOT take away power from the top end. We have yet to see any data so we do not know.

Adding cost and complexity to a turbo kit to gain 200 rpms of spool in an rpm band I am in for about a 1/100th of a second in the quarter mile or once on the parade lap at the local road course doesnt make sense to me. If it takes ANY power away in the RPM bands I will be in MOST of the time............. well, you get my point.

For the same reason Toyota put twin sequential turbos on the MKIV... The average driver of this car that uses the power to merge in traffic.... it adds power where its NEEDED. When you change the intended use of the vehicle, you need to match the power to where you NEED it.

 

You're still missing the point. Read up on the benefits. They are exactly what you would want if you're racing.

 

cant say i agree. if i hit the same boost sooner-who's faster?

 

Uhhh . . . it's called POWERBAND. Go drive a 500whp car that hits peak TQ @ 5500rpm and peak HP @ 7500rpm, then drive a 500whp car that hits peak TQ @ 4500rpm and peak HP @ 7500rpm. Tell me which one you'd rather have, whether its a daily driver OR a track car. . .

From somone who's had a 400+whp EVO that hit full boost WELL BELOW 3000 rpms, I can fully understand why folks get excited about quicker spooling big turbos. . .


EVOlutionary

 

Yea, but what do you know about racing cars.