GTX2867R, FM log mani, 1.8, 8.4cr
#41
Virtual Dyno results of my last car:
GTX2860, E85, begi cast manifold, stock '99 pistons, forged rods
#42
Don't give up on the GTX lineup just because one setup doesn't post dyno numbers you're looking for. People have hit 300whp on a GT2560, no reason at all that you shouldn't expect a GTX2867 to do it. As much as these turbos seem to like high boost sixshooter would be +300whp with a few more psi, it's not like he couldn't get there if he wanted to.
Virtual Dyno results of my last car:
GTX2860, E85, begi cast manifold, stock '99 pistons, forged rods
Virtual Dyno results of my last car:
GTX2860, E85, begi cast manifold, stock '99 pistons, forged rods
Ive been reading compressor maps a little and i think im going with the gtx2871. Wont even be breaking a sweat at 320whp and I could probably see 400whp someday if i get an allofit engine.
my next goal is 340whp on a stock 99 engine with manley rods and e85
#43
#49
Its tough bc im pretty sure the 67 can do it but i feel like the 71 will be able to do it easier with less tuning and have way more headroom. Plus its only 4mm bigger..which will be like 2 or 300 rpm less spool. Not even a big deal
#55
Ill be on stock pistons. I don't care about the actual boost number. I just assumed more boost would add more chance for det, wear the rings more, make the turbo less efficient, etc. I think the power would be more reliable at a little less boost pressure? Or am i retarded?
Generally speaking, torque is proportional to MAP times displacement. Engine breathing mods will move the torque peak further up or down the RPM band, but they won't really change the peak value by all that much. Since power == torque * RPM, this means that you get more power either by adding more torque (and with fixed displacement this means more boost) or with more revs. More revs means cams, head work, better-flowing manifolds, etc. The parts and knowledge for building a Miata motor to take boost are generally cheaper, more available, and easier to DIY than for revs.
From what I've read (never tried it myself), stock pistons can be used for higher boost better than stock rods can, but will reduce your margin for safety in detonation.
--Ian
#58
Can you help me with compressor maps? Does the map tell me how the pressure ratio effects the airflow? If I need 40 lb/min for 340whp, how do I know what pressure ratio that will be at?
If i was at 22psi (2.5 pressure ratio) flowing the 40 lb/min, this turbo would be most efficient and have plenty of headroom
If i was at 22psi (2.5 pressure ratio) flowing the 40 lb/min, this turbo would be most efficient and have plenty of headroom