Big Turbo Prolem

[babeboy]

I have a built 2.4 8:8:1cr with a ported and polished head. The problem I am having is I have a holset hx40. There are two housings now available for it a 55a/r and a 70 a/r Im trying to figure spool times on the two of them. I can also rev my engine to 7500 rpm because its in my Avenger. So who can help me figure it out?

[Turbocruiser13]

55a/r will spool around 3k the 70a/r should be around 3700

[babeboy]

Quote: Originally Posted by Turbocruiser13

55a/r will spool around 3k the 70a/r should be around 3700

Will the 55 keep pushing up to my 7500 redline.

[Turbocruiser13]

I think it may run out of steam just short of that...most likely around 6800

[babeboy]

Quote: Originally Posted by Turbocruiser13

I think it may run out of steam just short of that...most likely around 6800

I could also clip the turbo a few degrees right?

[Turbocruiser13]

Yeah you can clip it...TYPICALLY clipping will usually help spool times, so it might be worth it to get the larger a/r and have that clipped so you can have the best of both worlds

[babeboy]

Quote: Originally Posted by Turbocruiser13

Yeah you can clip it...TYPICALLY clipping will usually help spool times, so it might be worth it to get the larger a/r and have that clipped so you can have the best of both worlds

How does it help? I thought it created bigger gap so more gas can get through.

[thesrt4guy]

Clipping a turbo does not spool a turbo up faster, It is helped to achieve more top-end.

[babeboy]

Quote: Originally Posted by thesrt4guy

Clipping a turbo does not spool a turbo up faster, It is helped to achieve more top-end.

I know that. Thats why I didnt understand what ptcruiser wrote. He said it helps spool time, wihich made me think it helpd the turbo spool quicker. From my understanding the clipped part of the turbo lets more air/back pressure escape to help build more top end power at cost of low hp. a cliped turbo is more of a band-aid fix when you have a t3/t4 turbo with the amount of housings that are available. With the holset it seem the only possible way with only 2 available ar housing it seems like the only way to get me close to a verry friendly 63ar housing I would have to port and clip the 55ar housing.

[ipt]

Just get the .70 a/r housing. It will spool mid to late 3K rpms and it will not restrict the top end power at all.

There are alot of DSMs that run the .55 and rev to 7500 rpms, but with on 2.0L they can get away with that.

[babeboy]

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