I have a question about compressors. Would a smaller compressor with a smaller A/R spool faster that a bigger compressor with a bigger A/R? If the exhaust turbine and housing was the same on both units?

Still learning here.....

 

Yes, because the bigger wheel is heavier.

 

What if I had a big intercooler would the larger turbo spool up faster as far as filling up the volume? Im trying to pick one that will spool the fastest of the two. Both have T3 exhaust with the same turbine in .48 A/R but the compressor on one is a t3 with a .42 A/R and the other is a t66 bigger style compressor with a .70 A/R. Im going to run them as twins on a diesel but I am not sure wich one to pick. Im only turning 3000rpm's so I need something that spools ultra fast.

 

Would twins spool faster than a stacked turbo set-up?

 

you mean...
the smaller front cover , WITH the larger a/r ???

example:
the TC turbonetics from forced industions has the same wheels / bearing housings as the T series turbonetics...
but
the tc a/r's is .70 a/r and the T series is .50 a/r

you can still have the same turbine housing / wheel combo .........

the cover design is more inheriate to wether it is more a pressure desigh or flow design.......

 

Yes diesels are generally pressure orientated...

 

Ok yeah I think your getting to what Im looking for. Let me try again here maybe you guys can help me. I did the online search and found a few things.

I had a calc

engine
7.3L 455cu
diesel
ve-99%(not sure if this is right but the calc kept coming up with .99)

EVF @ 3000 RPM's=395.7cfm
for 2000 RPM's it =263.8cfm

not sure if it matters but I would like close to full boost at 16psi near or between 2000-2500rpms

N @3000rpm=190.13
N @2000rpm=126.75

Current turbo is a garret part number 445074-9010 It spools way to slow and at 3000rpms Im hitting 12psi. It has a .70 A/R on the compressor and like a 1.00 A/R on the turbine housing. The problem is I need to hit 12psi at like 2000-2500rpms.

Can anyone size me up some twin turbos for this diesel? I dont have the know how on the maps or turbos to even know where to start.
Also Im fighting egts off. Down pipes help and insted of cramming it all through one turbo I though twins may help me keep my egt's down.

 

If I had twin turbos is there any reason Instead of building a merge pipe, why I couldnt just route one of the turbos into the other turbos inlet? Would this cause a problem?

 

Now your compound boosting. So no, not in ur case. You have to merge.