littledcsrodshop

I know that these are not the best diesels to try to be getting more power out of. However my father has a 99 3/4
ton suburban with the 6.5 turbo, and he would like to have a little more towing power ( 8,000 lbs. ) We know that it will never run like a tire smoking duramax. We were just looking for a little more. It already has a k&N filter. Has anyone on the board ever had any sucess getting noticable power out of these or is it a waste of time. We have a shop and have both worked on hotrod cars & boats our whole life, However I am no diesel guru, and we don't want to start buying stuff just because some salseman behind a desk ( who has never picked up a wrench ) says it will boost your power & fuel milage by --% Thanks in advance , Scott

wannabe

Banks Turbo

Chip

Exhaust

The tranny behind these is only so-so (automatic)

Good Luck

Wannabe

phughes69

Scott, check out this:

http://www.62-65-dieselpage.com

As far as the 4L80E being so so, wannabe is completly wrong. The 1st version of it were ok, but had problems, but after 94 the trans got a lot better. The only thing that can beat it is the Allison trans in the new GM trucks. The guys on the diesel page have gotten 300 HP out of the 6.5 and still have it be reliable.

Pat

pullmytrigger

I run a hopped up 6.5 turbo, Ive been all over the web fourms.......I gotta run but search a thread in this section called "any 6.5 turbo guys out there?"......Im pretty sure I outlined what I have done to mine pretty well.......I'll get back to ya' but first off, two things B4 you do ANYTHING.....intake and exhaust.....the stock 6.5turbo is so bound up in these areas from the factory that you got to let it breathe before you put any boost to it or it will self destruct (WAY too high EGTs)......doug

MikeyFIN

Exhaust headers aŽla Humvee plus also the injector pump and then some and youŽll end up with 300hp and some serious grunt.
Know A guy who did these mods to his 6.5 and heŽs happy...can surprisea a Stock Duramax and yes the Trans needs to be prepared.
He has blown his twice sofar.

pullmytrigger

so a 6.5 Humvee has headers........?????

phughes69

Maybe a NA one does but I highly doubt it and definatly not the turbo diesel ones.

jordy

OK, not to disagree with you here, but I've never seen a Humvee with headers, at least nothing with a diesel in it. Secondly, just changing the injection pump isn't going to get you an extra 115 horsepower (6.5 turbo is 185hp at the flywheel). You're also going to have to do intake, exhaust, injectors, and a computer chip to take advantage of the mods you made, and then you're still dealing with an engine with a weak bottom end that wasn't designed for that kind of power to begin with. Good luck though.

phughes69

Scott have you checked ot the 62-65 diesel page yet. I would recomend putting on a new exhaust on it. A 3" down pipe and a good 3.5" system. Get rid of the cat if you are allowed. All the cat is is a soot trap. I dont know how restrictive it is but mine had a cat on it that looked like one of the old mid 80's flat cats. The other thing I did was put a better fan clutch on it. Anything that can inprove the cooling helps. Your truck has the hi flow water pump and dual thermostat's so not much more you can do to the cooling at that point. Once you can get the heat out (cooling and exhaust) you can start playing with adding fuel. I think what MickeyFIN is talking about is the Humvee's having a mechanical injection pump, where it is easier to turn up the fuel. On a diesel the more fuel you add the more power (and heat) you make. The reason the mechaical pump is an easy upgrade is because all you have to do is turn the adjustment screw on the pump and it adds more fuel. The electronic pumps are a little more complicated, and require a different resistor to add more fuel.

miamioffshore

Another major weak point on these engines is the pump mounte driver (PMD) a computer mounted on the fuel pump in the valley of the engine, this location is too hot and will eventually fry the computer causing weak starts and eventually no start. Check NHTSA boards for secret recall information, I did and it saved me thousands when mine on my Hummer failed. Only permenant fix is to relocate the PMD to the firewall where it's much cooler via a longer wiring harness