6.5 turbo diesel extra horsepower question

[Cees67]

i have a 6.5 turbo diesel with a mechanical injection pump. Looking on some info on the fuel screw to increase power as I'm putting a hx40 turbo and marine injectors. I am also installing new head gaskets and ARP head studs. Amy info is much appreciated

 

[Z71Hobbs]

Don't waste you time with the injectors...get regular ones. You need the matching marine pump to see any additional gains...and they are miniscule at best.

Watch your boost with the hx40, 15-20 psi at short bursts is ok, but above that you'll blow a head gasket. The stock turbo would spoil to around 5-10 under wide open throttle, then drop off to around 3-5 at cruising speed.

Don't go too crazy turning the screw. Try a little at a time...it helps, but not bunches. Do a feed the beast mod and diamond eye exhaust first...those are the best bang for the buck on these engines.

 

[Jorge6.5]

You should head over to dieselplace.com. That site is dedicated to gm diesels.

Sounds like your on the right but, Marine injectors will not add power.

 

[Jorge6.5]

Good call doing the head gaskets and head studs. 20psi will be no problem with that turbo. You should really consider gauges if you don't have them already.

Just noticed your in New York. Where abouts? I'm 30mins west of Albany

 

[deejaaa]

Increase Fuel
Reason to increase fuel supply is to get more power.
It is important to be conservative with this adjustment and carefully watch EGT. High EGT can cause piston damage. Buy and install an EGT gauge to monitor temps. High EGT and black smoke go together. If tow frequently or use max power extended periods high EGTs will damage/melt pistons. Short EGT spikes are not a problem because they don't keep pistons hot long enough to hurt them.
Take off small cover on drivers side of IP. It's very small and has 2 screws holding it on. Will need to remove throttle cable and bracket to see cover. Once cover is off, a little bit of fuel will spill into engine valley. Look for a small 5/16th Allen screw under cover that appears through small access hole. Screw rotates with engine so will need to have a large breaker bar on crank pulley nut to rotate engine while looking for screw to appear in access hole. A small flashlight and mirror helps to see this screw. It helps to have someone turn crank while watching for screw, but can do alone, but takes longer. It helps to remove throttle cable bracket and detach cable from IP. May also have to move linkage to get to access cover and fuel screw.
Once screw's in sight use 5/16th allen wrench to turn it. To increase fueling, turn clockwise. It helps to turn in small increments. Turning 1/6th of a turn ( imagine 12 O'clock to 2 O'clock) gave a good fuel rate. Could have gone 1/4 turn clockwise, but wanted to be conservative. It is important to increase airflow along with extra fuel or will just put out black smoke without extra power. Once screw has been turned put back together.
http://www.flashoffroad.com/Diesel/injectionpump/mechanicalpump.htm

 

[Cees67]

I didn't know the marine mechanical injection pump is different than the regular truck pump

Don't waste you time with the injectors...get regular ones. You need the matching marine pump to see any additional gains...and they are miniscule at best.

Watch your boost with the hx40, 15-20 psi at short bursts is ok, but above that you'll blow a head gasket. The stock turbo would spoil to around 5-10 under wide open throttle, then drop off to around 3-5 at cruising speed.

Don't go too crazy turning the screw. Try a little at a time...it helps, but not bunches. Do a feed the beast mod and diamond eye exhaust first...those are the best bang for the buck on these engines.

 

[cviola2005]

I have done almost the exact same thing. I currently have Hx35W, 2150 psi calibrated 6.5 turbo injectors, 6.5 turbo IP with fuel screw turned 3/8" (maxed out), all on a 6.2 bored .020 over. 20 psi boost max with 5-12 cruising. ARP head studs (these are a must) and I'm still blowing gaskets.

Currently replacing head gaskets (both blew) with 6.5 standard Felpro. Ive used 6.2 Felpro standard, 6.2 Felpro .010" thicker, Felpro PermaSeal, Victor Reinz, and OEM GM head gaskets with and without Copper Coat. All of them have blown. If this next set blows, I'm going for solid copper gaskets.

 

[someotherguy]

I always imagine the ultimate end of stories like this are a craigslist ad that goes something like, "Chevy truck, 6.5 diesel, lots of upgrades. bad engine"

Richard

 

[dave_erald]

Does anyone have the Injection pump numbers for the "marine" unit?
I keep hearing about it but don't remember actually seeing the pump number.

I thought the 4911 in my truck was the top shelf mechanical pump for these engines.

 

[deejaaa]

4911 is the best. people who diss the 6.5 have never owned one and should ****.