Hello all, been doing a lot of research lately on turbos and all the vast knowledge that goes with it! I was looking to do a single turbo build on my 03 marauder. I will be going with a all forged lower, and would like to see 450rwhp as of now, with room to go up when I build the transmission up. I was thinking a bw s400sx3 71mm would be a good match with a .90 ar opposed to the 1.10 ar that comes with the turbo as the standard housing. Now time for a few questions:

How easy will it be to swap out the turbine housings, and will I need to get anything rebalanced?

Does anybody know if there is a difference between a s400sx to a s471 to a s400sx3, etc.('sx3' from what I understand has a t4 flange)? I assume its just a shorter way of typing the turbo out?

Any other recommendations you guys have? Not looking to spend over $1400 for one, as im looking at around $1050 for the bw s400sx3 71mm with .90ar.

thanks for your help!

 

i had a gt45 on my 4.6 stroker, which is very close to what you want to run it is a 69mm compressor 75mm turbine and 1.05 ar. the .90 ar would probably better match as mine would spool around 3000rpm and all in at about 3600.

turbine housings are normally easy swaps if all other dimentions are the same, simply remove turbo remove v-band carefully remove housing (pray it is not rusted or coked on) then install the other and reinstall turbo.

400sx3 to s471 is a good jump in turbine size keep in mind a ar is a ratio not a size.

the s400sx3 is a good choice with auto, a little lazy for a manual with moderate goals for a street driver.

my car at 9# made 470 rwhp and 550rwtq stock engine other than a stroker kit( cheaper to buy than 4.6 crank, rods, pistons), it did however snap 2 stock intermidiate shafts on mildly built 4r70w's

 

i ended up getting a s300sxe 69mm with a .91 ar turbine housing. the s400 series is huge from what i have heard and would have been a pain to make fit. currently looking at a tial 44mm mvr wastegate and possibly a synapse BOV. i know tial makes some good stuff but has anyone heard of the synapse bov? im getting mixed reviews from research on the bov's, and getting a ton of negative reviews on their wastegates. synapse i believe has two different bov's, the DV and the SB BOV.