i know this type of thread is old but im curiuos.i dont tow and i dont want to get studs and head gaskets but i need more air,i was thinking like another twin thread and wastgating the twins to 40psi to save the gasket, but i read thats not a good idea,will a bigger single give me more volume with lower presure?thats all i really want is more air not more presure,maybe ill change the turbo piping to 6inch from the turbo thru the cooler and a custom intake haahaa,theres a used hx55 in the classifieds,will that cool things a bit and not blow a gasket?

 

also is the hx 55 a ballbearing turbo,i read that it is but the same info said the hx 35 was also,is this true,

 

I dont think tryin to keep twins wastegated at 40lb's is gonna work out to good, and i dont believe the Hx-55 is a ball bearing turbo, in know the 35 insint. But i would go with a big single or the twins with a set of studs and have it wastegated a little higher.

 

55 is too big and laggy-especially if you are wanting to keep things under 40psi. The 55 doesn't pay off until boost pressures higher than that, imo.

Twins are a great idea, and twins running at 40psi are a LOT cooler and denser than almost any single turbo.

I'd do the twins. At 40psi, the headgasket should be just fine. Twins are easier on the hg at 40psi than a single would be, imo-- because of the better efficiency and lower drive pressure.

 

Keep twins a 40psi is going to be very hard. About the only way you could do it is with external WG's.

 

So how much

can one expect from a 35/3b combination? is an external waste gate reccomended?

Either ways, i agree with HOHN, ull never get super High egts if you have a low boost set of twins that spools fast.. unless u run out of efficiency... and u dont have enough boost for ur fuel

Rick

 

On my one set up (35/14-3b/26) I can easily hit 55psi, even with blow off valves. And this is with small rv injectors and smarty only.
And about the only way your going to have super fast spooling twins with with a 35/12 and a 3b with a 22 or an s400 with a 1.10 A/R. You'll have great spool up but wont be able to support more than 450 rwhp.
I guess something else you could try would be a 35/14 on top and a k31 on the bottom. I still think you'd have a hard time wg enough of the top turbo.
The headache that would be involved with trying to keep twins at 40psi IMO you better of with a single.
The only twins I've heard of that dont need studs or orings at 50 psi are BD's. Even then I think you playing with fires.

 

I'm running a 58mm hx35 on top of a a 3e with a 38mm external wastegate and on valet mode I can hold it to 40 lbs. and somewhere around 900 to 1000 on the pryo. It can be run at the boost you want and it runs pretty darn good in my opinion!

 

[QUOTE=HOHN]55 is too big and laggy-especially if you are wanting to keep things under 40psi. The 55 doesn't pay off until boost pressures higher than that, imo.

so if the 55 is laggy and needs to run at higher preures how bout a sp66,theres one in the classifieds here for a decent price.

 

so if the 55 is laggy and needs to run at higher preures how bout a sp66,theres one in the classifieds here for a decent price.[/QUOTE]

With what you have know it might be alittle big. I think a 62/14 or a 64/14 would be better. If you went with some bigger injectors the 66 would work.

 

instead of wastegating both charger, wouldnt it work to plumb an external w/g from the manifold into the 5" downpipe? passing both chargers, into the big charger exhaust)

 

No because you need the wg'd exhaust to get the big charger spinning.

 

just run something like a 62mm S300 variant, set the wastegate at about 42-44psi and enjoy. don't mess w/ the boost piping, it's not holding you back any

 

wouldnt the wastegate open once both turbos are fully spinning?

 

you need to bypass the small turbine and use that exhaust energy to turn the large turbine