View Single Post
matty74 matty74 is offline
Eye of the Toiger
matty74's Avatar
Join Date: Oct 2005
Location: Sydney, Australia
Posts: 1,204
Originally Posted by TurboKraft View Post
With a good intercooler and good tuning, yes.

GT40R -- sure you could, if you're after even more power. And with 8.0:1 compression, I wouldn't worry about this engine being lazy.
Un-cork the B&B headers by modifying (enlarging) the secondary pipes and make them flow smoothly into a divided T04 flange, and add 2 small external wastegates, one for each secondary. Now you have twin-scroll headers (no not equal length, but we're not starting with expensive new ones, either). This is similar to what we're doing to Tom's 1984 930:
2010: An EFI Hot Rod Odyssey

Lest you worry about a GT40R spooling up late, either, we had a worn-the-#$%&-out 1978 930 racecar come into the shop once. Tired 3.3L 7.0:1 compression (or less), GT2 cams, Carrera manifold, poorly ported 930 heads, old EFI, twin-plug 964 dizzy. Big intercooler, but really poorly plumbed, lots of backpressure. GT4088R with largest A/R turbine. Dump pipe. Cobbled headers in an attempt to convert to T04 flange, with major restrictions. Doesn't make desired 17psi boost until 4,635rpm, and creeps up to 19.5psi. 485rwhp/458rwtq, and feels like it's going to blow any second.
Fast forward a few weeks and we've built new twin-scroll headers with twin wastegates, re-plumb the inlet & outlet of the intercooler, add a race muffler to quiet it down, and minor ECU re-tuning.
Same worn out engine now makes 515rwhp/528rwtq at 17psi, no more boost creep.
And full boost by 3,500rpm.
Thanks Chris, getting me excited about my build now.

1973 911 RSR clone powered by 77 3.0 turbo
Old 05-19-2010, 02:09 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #31 (permalink)