What turbo to go with my ED 66mm for twins

[TheBigNasty]

And yet a 62 over a similar 83 with a bit too much fuel is also FAR from a bottle neck. Truck made about 100psi on this dyno run and nearly 800HP. The air was there, but it had not been tuned at this point. After I slowed the fuel down, the SOTP meter showed a considerable increase, it has not been dyno'ed since.

‪TS 2009 795 HP‬‏ - YouTube

Do you have any proof besides sotp? Drive v boost v intrastage ?

 

[SHughes]

Do you have any proof besides sotp? Drive v boost v intrastage ?

unfortunately no. shortly after some afc tuning, i took it to the track and ran 120 through the traps...which backs up the 800hp, close at least. but it felt a lot stronger and deffinately smoother.

now i hope it makes 650 with a totally different set-up.
CompD Mobile Device

 

[jakemono]

And yet a 62 over a similar 83 with a bit too much fuel is also FAR from a bottle neck. Truck made about 100psi on this dyno run and nearly 800HP. The air was there, but it had not been tuned at this point. After I slowed the fuel down, the SOTP meter showed a considerable increase, it has not been dyno'ed since.

‪TS 2009 795 HP‬‏ - YouTube

That is awesome. Makes me feel a little better about wanting to go to a smaller secondary for a compound set.

 

[TheBigNasty]

I finally got mine hooked up right and with the 66/480 I haven't crossed 1:1 yet. Ive only taken it up to 60 psi so far, but at 60 psig manifold pressure I'm at 50psi TIP and ~20psig intrastage.

 

[SHughes]

taking a nother stab at post #7, since my phone effed it up when I tried to edit it...

I'm FAR from an expert, but I have learned that the secondary should be 75% the size of the primary...that is how mine is set up (62 or 83). my truck has convinced people to go with twins, as one put it, "the power just doesn't stop!"

With a 66 on top, put an 88 on the bottom. What variant or a/r is up to you. and don't forget a wastegate. I assume you have an internal, and that works for me, though a lot preach external.

food for thought I hope.

 

[RonA]

On my truck, a small secondary will generate higher boost for a given HP than a larger one. I have tried going from a 60 to a 62 to a 64 with the same primary and the hp level went up each time while the total boost dropped each time. Yes, it spools slightly slower, but on the top end you are fighting less drive pressure, and making more power. Easier to keep gaskets in place too.

 

[SHughes]

makes sense Ron

 

[RonA]

There are good and bad things for both methods. Lately I've been seeing a few people running too much turbo for their power level. Not in this thread, but it is common.

 

[Jim Fulmer]

There are good and bad things for both methods. Lately I've been seeing a few people running too much turbo for their power level. Not in this thread, but it is common.

Agreed, remember the old days when we ran a 40/3B combo....wait, I still do!

Jim

 

[BgBlDodge]

not true, its rotating mass and more importantly its farther out from centerline while also theoretically pumping more air which creates more resistance.. a 62/71/14 will spool considerabley and noticeabley faster than a 66/71/14

I'm gonna have to disagree. Going from a 62/71/13ss to a 66/71/13ss I lost MAYBE 50rpm of spoolup. I couldn't even tell a difference between the two. Nothing else on the truck changed except the compressor wheel.