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turbo guys come in AR sizing help

6K views 17 replies 7 participants last post by  WMD 
#1 ·
Okay all you twin turbo guys what size AR housing are you running? Curious to know what rpm you are pulling to as well. I'm considering twin 64s or twin 67s if there's not much spool difference I will go 67s. Any and all info would be great!
 
#2 ·
The 6466's will spool a little faster since they're ball bearing. In my opinion it is not that noticeable, 6 speed setup is would spool faster with 6466's. If it's a auto setup you probably won't notice spool up.

As for exhaust housing .81 AR's would be the way to go. Pulling mine to 8,500 rpms
 
#3 ·
It's all math my friend. How much power are you trying to make? That will decide what size turbo you should run. As far as hotsides...run the smallest one possible that doesn't interfere with your power goal. I ran .63 hot sides on my 57's. It was the middle A/R for the turbos and they worked well. They did spool noticeably slower than when the small hotsides were equipped.
 
#5 ·
Goal is 1k rwhp..looking for a setup that's capable of mods 8s and still keep me around a 3800 to 4k stall converter To keep it nice on the street. .81 AR is what I was leaning towards but didn't know if I'd need a converter change for that size. I've been looking at borg s366 but notice there smallest AR is .81... MT where do you start seeing boost on the stick? If your seeing 10 plus PSI before 4k rpms then it should wrk well on a Auto with 3800 to 4k stall. Y2k what stall speed you at?
 
#11 ·
How do you mean? Boost? 30 psi. They will make more. These 6466s spool around 5000 RPM. That's with an advanced turbo cam set.

I had some 6157s with .58 A/R before that were awesome turbos. I had those up "all the way" and saw exactly 30 psi. Those turbos spooled at 4200-4300. That was with a heavily advanced Ford GT cam set.

All have been T4 flange.
 
#14 ·
I'm saying.... a turbo race combination will have a later spoolpoint. Not full boost... but almost an on/off switch where that boost is just climbing faster than your gauge can keep up with. That is right around 5000-5200 with the 6466s.

I could never get the car to dyno well. It would always spin.

1/4: 61s and GT cams: 8.86@160mph. 1.48 60' 30 psi. Stock PCM. C16 and meth.
1/4 64s and turbo cams: 8:36 @ 170 mph. 1.42 60' 30 psi. Pro EFI. E75. Not even E85. No race gas. No meth. All day every day.
 
#18 ·
Had a good night last night testing
9.22@151 pedaled 2 times, 9.17@150, 9.12@149 with 1.39 60 foot
getting there. Actually turned down the boost a bit to make in down the track.
 
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