GM-5 turbocharger

[turbovair]

Ive heard a lot of turbo talk lately, and have heard of virtually every turbo..1,3,8, but have not heard much if anything about a 5. Is this an undesireable unit? Rare? Is there a better unit that will bolt on? My truck is VIN code "F".
Thanx.

[gmctd]

GM-1 - 3 used on 92\93 mech inj engines
GM-4, -5, -8 used on '94 up electronic injection
GM-4 smilar to 1 - 3, with vacuum wastegate actuator
GM-5 had improved compressor, turbine and exhaust flow, with relocated wastegate
GM-8 was the final version, with improved wastegate shaft\bearing area
GM-4 thru 8 can be used on '92-'93 mech inj engines by relocating mechanical wastegate actuator. Manifold mounting and
exhaust hookup is identical

jd

[StephenA]

What other turbos are available for 6.5's and what are their advantages over a GM8? If I upgraded from my GM1 to GM8 would I have more power or just more reliability? What would be the best turbo upgrade for my 92 mechanical? Bill Heath says my GM1 with a Turbo-Master will produce 14 psi...
What intercooler is best?

[cruzer]

GMCTD, I thought the GM 8 used a different exh. manifold? And that a Turbo Master would difficult to adapt if at all. What are the benefits?

[gmctd]

GM-3 thru -8 exhaust flange is identical; have not seen GM-1, but would assume same pattern.
Compressor housing to cartridge flange, and turbine housing to cartridge flange were modified for efficiency improvement.
Compressor wheel and turbine wheel are essentially identical.
Exhaust elbow for GM-5\8 vastly different from GM-4 and previous, but downpipe mounting is identical.
Wastegate acutator was relocated several times during improvement process, which prevents direct bolt-on to upgraded turbo series. It can be done, with a little mechanical ingenuity.

GM-1 thru -3 used mechanical wastegate actuator, where spring tension forced closure until ehaust pressure exceeded spring tension - simple but effective.
Aftermarket boost controllers modified spring tension, which required more exhaust pressure to blow open wastegate. In some cases, oem control is replaced entirely, using only the aftermarket device.

Electronic injection systems utilize PCM-modulated vacuum against atmospheric pressure for wastegate control.
Aftermarket mechanical boost controllers could be used to replace these, but would require some programming steps to defeat PCM monitoring of applied vacuum versus boost response.
Also, very close attention to EGT and Boost Pressure gages.
Would also totally void warranty.

Again, with a little mech 'engenuity', the mechanical servo can be installed on the GM-4 thru 8 series, with the -5 and -8 being best choice for better exhaust flow and compressor efficiency, the -8 for reliability - the wastegate pivot area was improved over the -5.

After market? I have been wanting some hands-on with the Mitsibishi TE06H for compressor, turbine and wastegate size comparison to the the GM-8.

Charge-air cooler - the units John Kennedy offers are probably the max size for the '88 up trucks.
'87 back have more options, with more room in front of and below the radiator available for installation.

jd

[patrick m.]

We lost some great reading when "pepto-bismol" fell into the worm hole. :(