pros and cons, DSM flanged turbos/manifolds

[junkyardgsx]

I have searched and searched for a little info on why most people are sticking to using a DSM flanged turbo manifold and turbo and I need some experts on the pros and cons of this. My pros are, bolt-on to factory manifold, internal gated or gated on 02 housing, factory oil lines may work, bolt on down pipes and O2 housings. My cons are limited space of turbocharger placement, O2 housings/down pipe more restrictive than a conventional down pipe, most factory manifolds have cracks after 10+ years, pricing of all components needed to work almost the cost of a complete custom system( for higher HP goals). So please help me with some pros and cons

 

[streetillEagle]

I believe it's not merely choice or preference it's that they are more readily available at the right used price. I have my Turbonetics turbo on a stock Dsm manifold because that's the way I bought it used. I'd love to run a Shearer or punishment manifold W/t3 t4 flange if I had the money.

 

[JusMX141]

It has to do with turbine flow. The general rule of thumb is that DSM-flanged turbos flow very poorly on the turbine side- especially those made by Precision.

I know of a case where a friend of mine swapped from a DSM bolt-on turbine housing on his PTE 6031E to a .82 a/r T3 turbine housing and picked up nearly 10lb/min of airflow with making NO other changes to his setup or boost level.

On our cars, I'll tell my customers to base their turbine housing flange selection on the total airflow they're looking to run....under 50 lb/min, the DSM bolt-on housing should be fine. From 50-80 lb/min, you'll want a T3 flange; over 80 lb/min you'll want a T4. Of course there are larger / smaller turbine wheel selections that bridge the gap between the housings as well....a DSM bolt-on housing with a large turbine will likely outflow a T3 housing with a small turbine.