DOHC turbo sizing

[brian89gp]

I respect you, the DOHC just breaths a bit better then a 3400 and powerband is quite different.

[timg]

Brian is right on. If I hadn't gotten the 60 trim T04E, I would have gotten the 60-1. 300 hp sounds very do-able for a 3400 with a turbo and should be an awesome setup.

Tim

[brian89gp]

I was actually looking at a flow map for a T61 turbo and it looks quite good. Sized somewhat inbetween a 60 trim and a 60-1, except its got much higher boost potential. 10psi is just at the bottom of the map, and its got a 360* bearing and cost less then a 60-1. I got nothing against the 60 trim, if I find one for cheap then I'll probably end up using that (the GN turbo fell through ).

Without back to back tests of different turbo's on the same motor it's very hard to tell which one is better. Its aggrevating as hell trying to pick the best one while keeping in mind that numbers on paper and numbers in the real world don't always match.

[brian89gp]

And about the 3500 spool on the 60 trim, that is probably ideal. Mine I can spool at 1000 but it doesn't do a damn thing except make a lot of noise. I hit 3-3500 and it starts pulling, before that it feels doggish like every other NA DOHC I've been in (pulls a little better then a NA, but not enough to justify a too small turbo). A set of cams would probably do wonders.

[nocutt]

And about the 3500 spool on the 60 trim, that is probably ideal. Mine I can spool at 1000 but it doesn't do a damn thing except make a lot of noise. I hit 3-3500 and it starts pulling, before that it feels doggish like every other NA DOHC I've been in (pulls a little better then a NA, but not enough to justify a too small turbo). A set of cams would probably do wonders.

I agree 3500RPMs full boost on a 3.4TDC turbo is ideal, especially a manual...on an auto, full boost needs to be lower, therefore one needs to plan what trim or housing needs to be used...
this is why turbo sizing is time consuming...two turbos put on the same engine respectively will output differently due to a number of variables...the rule of thumb is to always size bigger...due to the human nature...more power!...

whether you use forged parts or ultra-forged parts, physics will always play a role...keep RPMs relatively low, as RPM increases...so does tensile load...geometrically!!...with a turbo...it isn't neceassary?!?