Building a set of twins

Graphic Man

Graphic Man

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Aug 24, 2006
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i am going to start getting everything together to build a set of twins.. "see sig for mods"

going to sell the sled puller 66 and start fresh

i am looking for a good street/strip set with room to grow a little.

what is your input for turbos?

here is what i am thinking 62/14 - S400 or S300

how much of a difference is there between the S300 and S400 ?

Thanks
Scott
 
A 62/14 , and your sp66 are both s300 variants. The s400 is a pretty big huffer, and it is the big turbo in several twin kits already on the market.
 
This will probably get some people riled up but long live the hx40/bht3b combo its the oldest setup out there and still working well.
 
Depending on what your goals are, the K31 turbo is getting more popular for a primary turbo in towing twins. Piers has made some sets, ATS uses it, Industrial sells a set with it I think, and I am sure more.
 
RCCX said:
This will probably get some people riled up but long live the hx40/bht3b combo its the oldest setup out there and still working well.
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I agree, i just wanted to see if there is anything better or different with all that is out today.....i have not been keeping up with it

Thanks
 
Ok so a 62 and S400

what size E/H on the 62....12 or 14

i know it will spool quick but what will the 12 do for drive pressures.?
 
Graphic Man said:
Ok so a 62 and S400

what size E/H on the 62....12 or 14

i know it will spool quick but what will the 12 do for drive pressures.?
Click to expand...

I would use a 14 if you are going to use the internal wastegate, or the 12 if you are going to use and external one. A 62/14 over an S400, handles 600hp pretty well at the track. I'm at somewhere close to 900 1/4 mile passes on my twins. Still working like a champ. Gotta love the sound of a S400...

Paul

P.S. Oh, yeah... About 45,000 miles on the twins too! :D
 
paulb said:
I would use a 14 if you are going to use the internal wastegate, or the 12 if you are going to use and external one. A 62/14 over an S400, handles 600hp pretty well at the track. I'm at somewhere close to 900 1/4 mile passes on my twins. Still working like a champ. Gotta love the sound of a S400...

Paul

P.S. Oh, yeah... About 45,000 miles on the twins too! :D
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so should i go int or ext. waste gated ??

the external W/G would be a blow off valve right??

i figure i will be around 625-650hp
 
Graphic Man said:
Ok so a 62 and S400

what size E/H on the 62....12 or 14

i know it will spool quick but what will the 12 do for drive pressures.?
Click to expand...

I would think the drive pressures would be fine on a 62/12 with your setup, thinkin a 14 would be too laggy for a street/strip truck maybe on a CR
 
if you go with an external wast gate dump the exhaust from infront of the first charger and return it after the second or use a sepprate pipe for it
dont dump your boost blow off valve
 
The S400 is a clock wise rotating turbo, it is much easier to snug up against the block.

The HT3B is a CCW rotating turbo, you can make it work but plumbing is a bit more of a challenge.

BHT3B (7% more efficient then the HT3B)

MVC-002F-1.jpg


I would look at a K31 or a GTA42A. It is the same size as the s400, it just has a w/g exhaust housing.
 
A k31 is the same size as an S400? Or the GTA42A, or both?
 
Your standard S-400 has a 74mm inducer, the K-31 has a 71mm inducer. I'm in the process of biulding a set of twins with my 64/13ss and the K-31 right now. I want to try the 64 first and if it's too laggy I'll get it made into a 62. I'm looking for these twins to support around 700hp+-.
 
i am thinking on trying a 64/14 with the S400......i wonder how laggy it will be for the street
 
In twins the rule of thumb is that it will spool slightly slower than the smallest turbo would as a single.

I am going to try the A5K that I have as a single and if I don't like it, it will be in twins. Not sure what I will use for a secondary just yet. Will see what comes up for sale for the right price. Hoping for 600hp.
 
97crewcab said:
In twins the rule of thumb is that it will spool slightly slower than the smallest turbo would as a single.

I am going to try the A5K that I have as a single and if I don't like it, it will be in twins. Not sure what I will use for a secondary just yet. Will see what comes up for sale for the right price. Hoping for 600hp.
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i agree

i may have a deal on a 64/14......i guess i could always send it back in for a 12 housing if i don't like it
 
Cummins Express said:
if you go with an external wast gate dump the exhaust from infront of the first charger and return it after the second or use a sepprate pipe for it
dont dump your boost blow off valve
Click to expand...


not sure if i understand
 
see if this helps but the waste gate between the exhaust manifold and the first charger with the waste gates exit line going back into the exhaust after the big charger or just dump it to atmospher.

if you use a blow off valve it will dump you charge pressure but not drop you back pressure (exahust) as well
 
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