6.2 boost compaired to 6.5 boost

[bshull]

I am under the impression that a stock 6.2L with a banks turbo needed to be limited to 10 psi max boost, where as a 6.5 turbo you would want it limited to 15 psi boost. If you exceed these numbers and held the engine there you could blow it up

I am also under the impression that the 6.2 and the 6.5 are almost the same block, Why the difference in boost? Compression?

Here is what I am considering, I have a 95 burb with a 6.5 turbo and the engine has lots of blowby and is tired. On craigslist there is a 6.2 that was running with 60 thousand miles on it for $500.00. I am considering buying it to build up for my burb this winter. I know I would need 6.5 heads, anything else?

Thanks

Brian

 

[WarWagon]

The Banks turbo is NOT a GMx turbo. It may have a different and lower choke PSI then the GMx turbo.
The 6.5 head gaskets are designed for being used with the turbo. Older 6.2 head gaskets were not. So a safety margin for this 'stock' engine could be there.
It is recommended that you use 6.5 head gaskets on the 6.2 for turbo apps.

You should tear down the 6.2 and check for cracks before starting to build it. It may be a cracked boat anchor or a good block.

 

[buddy]

If you switch the heads and use the 6.5 gasket then you have resolved the issue with boosting a 6.2, from what I have gathered.

Anyone comment on keeping the 6.2 heads and just changing gaskets? Are the 6.2 heads smaller, less flow?

 

[WarWagon]

6.2 heads in use on mine:
Larger exhaust valves...
Different precups. You could change this with $$ thrown at it.
watch the unusable 1982 course injector thread heads.
You will need the 6.5 injectors. Change 6.2 DB2 IP timing after that.
Clearance issues with GMx turbo manifold and injector lines. Header wrap and it will work.

GM3 at 14 PSI max sustained with load, 1/2 turn on IP was too much due to smoke and EGT's. 1/3 is closer to about right. ARP head studs just to be sure I can beat on it like this... 8000 miles hard use towing and still going strong.

From precups I suspect - more smoke and 3 MPH loss at WOT ~60 MPH towing a trailer up a hill. vs. the 6.5 it has before the 6.2 repower. Same MPG.

 

[searstractorfan]

My 93 has 6.2 heads, and Im pretty sure someone put the course thread injector heads on it!!! my pumps turned up all the way supposedly and I have spiked boost to 20psi(waste gate was stuck)..I usually ran around 12psi and no problem other then block temps were CRAZY high, but that was due to a cheappy thermostat im almost 100% sure now....So far it still runs good, I currently have waste gate open so I make boost only at wide open throttle and at like 2800rpms plus and its only like 2 psi max.....

 

[Missy Good Wench]

With the 6.2 the head gaskets need to be updated to the 6.5 gaskets.

The 6.2 gaskets if they are the newer felpro units will hold but, the 6.5 gaskets are better.

The difference in these engines is ONLY the bore. The 6.5 is roughly 2mm larger, thats it.

I am in the process of swapping a 6.2 back in where a 6.5 came out. Going to use the GM4 turbo with the DS4 injection system.

This truck has had a turbo master installed before and will continue to have such. Boost set to about 12 PSI or so.

Going to use 6.5 gaskets with this along with the 6.5 heads.

The boost is really only important if you get past 12-15 PSI

The Banks turbo is a non wategated turbo and is limited by what the drive side can handle.

It will peak at around 10 PSI.

The Banks Kits would wake a 6.2 up to around 205 Horsepower. At the time the GM turbo 6.5 came along, the Banks was making better power.

Have fun.

Missy

 

[bshull]

Thanks for the fast replies. If I do this I plan on a full dissemble and a rebuild with updates that I think are worthwhile. It will probably take me all winter to find time and money. The wife will kill me.

Thanks, I know I will be back with many more questions.

Brian

 

[ak diesel driver]

Check out missy's thread you'll also most likely need a diff pan.

 

[buddy]

If shooting for reliability there are some known good things to do and some conventional may not be that good or matter so much on these diesels. Just ask away, and enough people will tell you how to spend your money.