Your better off (cheaper) to compound them. Then run them both through the stock intercooler. You could buy it all for under $2300. Thats top and bottom turbo with all the piping out the door!! And that Would be enough air for well over 600hp. Put the bd twins to shame!! except bd's 750 and 850 kits.. I'm not excactly sure what an offroad vp pump is?? you mean like a hotrod pump?? If you still got stock injectors then don't even think about twins. Thats no where near enough fuel for twins.

 

im putting 150 or 200 hp injectors in it first. so the stock intercooler could handel both turbos ok? the off road pump is for a semi. its bigger than a hot rod or the dragonfly pumps the hotest pump you can find from a performance shop is 260hp and mine is 275. runs alot of fuel.

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what do you mean by tuning twins?

 

Hmm never heard of the pump... owell.. 150's are the smallest i'd go for twins unless I was doing something like an hx35 over an hx55. Then the most I would go with would be 150's. 200's will be enough to spool twins efficiently. Your stock intercooler will be fine as long as you don't run a ton of boost. like over 70lbs. You'll need a weekend to install the twins injectors and head studs and then another week or two to play with them and tune them in. Twins aren't just a bolt in thing. If twins are not tuned properly they can be very laggy and work against eachother.

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You have to adjust both wastegates to tune them. usually you set the top turbo to half of the total boost you want.

 

ok that makes sense. im gona go with the s400 i think. im lookin for 600hp. i looked at the s475 and thats a huge turbo . do you think studs alone will be ok without orings? think i can get 55 to 70 pound of boost out of that?

 

The s400 is just the model of the turbo. Kinda like an s300. Then they make s357, 362, 364, 366, etc..... the 475 will be a good match for that hx35 and it will still give you room to grow if in the future you'd want more. The limiting factor in an hx35 over an s475 is the hx35. But you will be close to 600hp worth of air....and you'll defanately be seeing 55-60 psi with twins. Just remember with excessive boost your going to start needing supporting mods like valve springs and possibly orings. I would do studs at first and if/when you blow your head gasket do orings then!!

 

how does that work with the second turbo? do you nees a waste gate that can handle 70 psi or just no waste gate on the second one?

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ok il just run the s475 then and oring it when it blows . do i need a wastegate on my big turbo? one that can handle 70 psi or just no wastegate?

 

I don't believe you will need one. If your two worried about it then run an egate in the hot pipe or run bov's in the cold pipe. That'll keep your psi down to a lower level. I know a guy running an he351 over a ht3b and he keeps drive pressure down with 2 55psi bov's in his cold pipe. Running those two turbos with ddp200's and no studs..... but he is also running an HO pump so its prob only around 500hp.

 

only around 500?

 

Yes a ho pump is only good for about 500hp.. maybe a little more. An so pump is good to about 650hp. After that you need a monster pump or something along those lines.

 

Hmm im building over 500 with a HO pump and a single turbo