Wastegate on twin turbo

N

nilsson

New member
Joined
Sep 28, 2009
Messages
193
Have plans for building a twin turbo setup for my 12v cummins.
Have checked som threads and picturs, but not really seen how they are wastegated. Have seen a setup for a gasser, and they had the primary wastegated but not the secondary. But they had a external wastegate that from the manifold to the downpipe, to prevent the primary to over spinn. How shall they be adjusted to each other? Someone that can give me a fast education in twin turbo charging on cummins engine? Suggestion on turbos for about 650 hp. What material in hot pipe, pressure pipe. Bad matched turbos be twice as bad in a twin turbo setup or?
Regards From Sweden
 
I think you have the primary and the secondary confused. The primary would be the large atmospheric turbo, if you size this turbo well enough you wouldn't need to wastegate it. The secondary is the smaller turbo and is usually wastegated to prevent from overspeeding it.

Typically people use 3" schedule 40 or so for the hotpipe, and 3-3.5" for the coldpipe. The smaller piping will improve spool.

For that size of a turbo setup I would look into a hx35 or s300g over a s471,s475, or ht3b. The s300 and s400 series turbos are nice because they are common and easily to upgrade.
 
Last edited:
Got a 38mm gate on the top turbo, 3" hot pipe and a 50mm gate on the bottom turbo. With the twist of just one external boost controller, I can go from 32 psi to 65 psi regardless of fueling. The primary is a GT42 with a 1.15 A/R housing. The top turbo is a HX40 with a 16cm H1C housing
 
Sorry mixed the name of the turbos. Thanks for your help. Here is a picture of what a mean. Regards
wastegate.jpg
 
White Knight said:
I think you have the primary and the secondary confused. The primary would be the large atmospheric turbo, if you size this turbo well enough you wouldn't need to wastegate it. The secondary is the smaller turbo and is usually wastegated to prevent from overspeeding it.

Typically people use 3" schedule 40 or so for the hotpipe, and 3-3.5" for the coldpipe. The smaller piping will improve spool.

For that size of a turbo setup I would look into a hx35 or s300g over a s471,s475, or ht3b. The s300 and s400 series turbos are nice because they are common and easily to upgrade.
Click to expand...


Just a question. How thick is the walls in 3" schedule 40 ?
Will buy the piping in Sweden, soi have to translate.
Thanks
 
nilsson said:
Sorry mixed the name of the turbos. Thanks for your help. Here is a picture of what a mean. Regards
wastegate.jpg
Click to expand...

Many times there is (1) gate in the manifold, and (1) gate between chargers (but that is also dependent on turbo sizing.. I would rather not waste the energy on the manifold side to atmosphere, myself, so I would attempt to choose my turbos as such)


3" sch40 = .216 wall thickness


3" sch10 is just a shade larger ID than the ID of an S300 non-gated exhaust housing outlet, fyi
 
Last edited:
Has anyone used a pro52 with a hx35 in a twin setup? do you think it would be worth it cuz i can get ahold of on pretty cheap
 
i dont know much about the pro 52's but i think you wil be better off with ht3b for cheap.
 
Actually,3" pipe outside dia. is not 3".It is 3 1/2".Pipe measurements don't go to outside dia. until you get to 14" pipe.Just some useful or useless knowledge for you all.

In Sweden I reckon you use mm,correct?So for a 3"(80mm) schd.40 the pipe would be:

Outside dia. 88.9 mm (3 1/2")

Inside dia. 77.92 mm

Wall thickness. 5.49 mm

Hope this helps.
 
Thanks for the info.
Did you know some more than source automotive that sell parts for DIY twin turbo builders?
Thanks
 
nilsson said:
Thanks for the info.
Did you know some more than source automotive that sell parts for DIY twin turbo builders?
Thanks
Click to expand...

sorry, no. i do know that alot of twin builders get there parts from Rip for their kits.
 
You must log in or register to reply here.
Back
Top