I am in the process of building my own HX40/ S400 twins. The pipe that runs from the 400 outlet to the intake on the 40, should that be 4” or 5” pipe? Anybody know what size the outlet flange on the S400 is? and what kinda filter are people running on twins and where should i get one?

 

I've seen 3 to 4" used for that pipe, I'm planning on using 4" for my setup.

 

Call up Rip Rook

or look up Source automotivebiz. com, and see if that offers any help.. I do have his 35/400 set and i do know that you need five inch pipe no questions asked for the exhaust. It is huge. I am using an AFE cone shaped filter that he sells for his kits, and in answer to ur first question IIRC the hotpipe is 3 inch pipe...

Hope that helped..

Rick

 

ok ill do that. but i am asking about the coldpipe.

ok i'll bite whats IIRC mean?

 

IIRC

If I Remember Correctly, but if your talkin coldpipe, its four inches...

Rick

 

I've heard if you make the cold pipe out of 3.5" it will help spool the big charger just a touch. Something about keeping the air velocity in the pipe up a bit??

I'm gonna try it on the next set
Chris

 

Lemme know how the HX40/S400 works out for you. I'm now leaning towards it than from my original idea of 40/b3. But then again I'm just researching, us unlucky college people can't just go buy twins.

 

IT will spool about the same as a 35

But it will give you a bit more on the top end, and a little more efficient useable boost. Ur right about the not bein able to buy twins till after college, i got mine when i got my first real job...

Also the B2 will flow more air than the 3B, so its a wise choice.... Good luck on the project!

Rick

 

Yep, I used to have a "real" job but decided being poor and going to college was better than working 60 hrs a week making descent money. I do however get to get some free hp here as soon as I get my lazy butt around to doing it. I finally hooked up that fuel press gauge and I'm making 10-12 idle and 15 psi at 2k rpm. Lookin like a shot OFV but haven't pinched the line to find out for sure.

 

LP might be out as well..

go ahead and listen to see if it Ticks.. U have a PM...

Rick

 

yeah and us high schoolers got it even harder. the $ i have for twins is money i have managed to stick back and keep over a 4 month period.

so i am thinkin 5" from the filter to the 400 inlet and 4" from the 400 outlet to the 40 inlet. sound good?

 

An HX40/S400 twins setup will not spool "about the same" as an HX35. It will be noticably laggier.

 

A ride in Mcummings dually

made me reach that assumption, IIRC he has a 40 over an s400.. and that sucker spooled and went!

Rick

 

I'm pretty sure he has a cam and that would affect spoolup in a positive manner. This is not a fair comparison since most guys do not plan on installing a cam.

 

40/B2's spool as fast as the 40 they are running. While it's un-noticable to me, Lavon says that it takes about 25 more feet before the twins hit when we switched his truck from the 35/b2 to a 40/b2. No cam in his truck.

brnadon.