rmay635703
03-23-2004, 11:04 AM
Is there any way I can put a part number 12556124 GM-8 (made by Borg Warner) turbo on a 6.2ltr Diesel?
On an off topic I have two old 6.2 subs a 1989 and a 1982, one thing that is disheartening to me is my 1982 with a Turbo 400 3 speed tranny gets consistent 21mpg (in town or highway), my 1989 with a 4 speed gets about 16-18 in town and about 20-23 (usually 21 just like the old guy) on the highway.
Why is this?
gmctd
04-01-2004, 07:35 PM
The heads were redesigned in 1990 to allow for fitment of the turbo exhaust manifold. Several things were done, but main difference is the injector angle was tilted more to the vertical, and a shorter injector was used for clearance.
Get these '90-up heads, and the 6.5l manifolds, and it is workable.
Check the differential ratios between the two Subs, also noting whether 1500 or 2500, for the difference in mileage.
T400 was usually 2500, with 4.10 ratio, no EGR.
700R4 was usually 1500, with 354\373 ratio, EGR.
bowtiebob
04-08-2004, 02:31 AM
Before I got my 'Max, I had a 1990 6.2 with the three speed auto. What exactly would I need to do to put some sort of turbo on the truck? Would it be worth the hassle to do? Now that my little brother has it decked out with lights and tires, he wants to give it some bite underneath the hood.
On a side note, in three years of driving I never saw over 16 mpg.
Bob
gmctd
04-08-2004, 07:59 AM
The power increase is worth the effort.
Turbocharging increases Diesel efficiency, but economy usually suffers due to increased activity by driver's right foot.
'90 models should have the late heads - later turbo versions got revised pre-cups, but standard -cups will function as normal.
The air conditioner evaporator housing will interfere with the 6.5L turbo setup. I fabbed one up with cases from S-10\S-15 trucks. Non-ac trucks have clearance.
The turbo down-pipe will require fabrication, or a good muffler shop can bend one to fit.
The 6.5L manifold is of a standard T-3 turbine size, so other turbo options are available to avoid clearance hassles.
Revision - above info was for the '74-'91 bodied trucks. '88-up new body-style trucks are a no-hassle upgrade.
6.5L turbo hardware is bolt-on, including exhaust, no clearance problems. '92-93 turbo used spring-controlled wastegate, no computer required. Turbo requires HD radiator option. Edited by: gmctd