Posted by Don in Missouri [97.64.167.2] on Wednesday, March 11, 2015 at 11:18:41 :
In Reply to: Best turbo upgrade for 4bt? posted by Sterling Luttrell [99.98.76.231] on Saturday, March 07, 2015 at 23:42:00 :
If you have a p-pump motor, you probably already have an HX35. I upgraded the H1 turbos on my 6bt and 4bt (both rotary pumps)to HX35s. I am very happy with this upgrade, especially with the 5 speed behind the 6bt, the HX35 builds boost much more quickly, so it reduces the boost lag with every shift.
Before you swap to a different turbo, you might just try an adjustable boost elbow. You can get one off ebay for about $15. You can adjust it to hold the wastegate closed to build higher top end boost.