8100 Tuner

[Tom Meyer]

The intake manifold has the real restriction, when you look down in the intake divider floor there is a hole that is no bigger opening than the throttle body. Air going into the engine goes threw the throttle body to a hole that drops down to lower level a goes to the intake runners. The intake air changes directions many times before it gets to the intake valve. By removing the floor it becomes a big open plenum with long intake runners. In order to remove the floor you have to cut the bottom of the intake off then weld it back on. It is not a Saturday afternoon job. I got another intake from junk yard to modify but have yet to bolt it on. At that point another trip to the dyno to see the difference. Tom

[Alan Roehrich]

Originally Posted by Tom Meyer

The intake manifold has the real restriction, when you look down in the intake divider floor there is a hole that is no bigger opening than the throttle body. Air going into the engine goes threw the throttle body to a hole that drops down to lower level a goes to the intake runners. The intake air changes directions many times before it gets to the intake valve. By removing the floor it becomes a big open plenum with long intake runners. In order to remove the floor you have to cut the bottom of the intake off then weld it back on. It is not a Saturday afternoon job. I got another intake from junk yard to modify but have yet to bolt it on. At that point another trip to the dyno to see the difference. Tom

It needs more than the plenum opened. For the engine to make good power at an RPM high enough for it to accelerate through the gears, it needs at least a 100MM throttle body, and all of the restriction removed behind it. The plenum is currently a reservoir for air, that empties rather quickly, and cannot be refilled quickly enough. Ideally, the throttle body needs to be moved back about an inch. Widen the inlet substantially, then use a throttle body spacer to mount a minimum 100MM throttle body. You can then change the duct from the air cleaner to have a larger radius, and eliminate the big restriction required to clear the shroud.


Removing the baffles, and opening up the plenum can be a double edged sword. If enough restriction is not removed, air will enter the plenum and slow rapidly, so the back half of the intake can be starved for air, you get uneven air distribution.


The runners are a bit long, even for the goal GM had of maximizing torque, even at near off idle RPM.



Also, if you move the PCV inlet and put some baffling in it, you'll get rid of a lot of the oil consumption, while also helping the crankcase breathe a bit.


I've worked with a few people who have modified the intake, with mixed results. A good example is a video Richard Holdner just put up on youtube. In looking at the intake, there were several things NOT done. The first is how the larger throttle body was installed and located. Too far forward, and too restricted. I do not think radically shortening the intake runners will work well on a tow vehicle. But porting them will.


I actually bought a spare 8.1 and an Allison from a friend of Adger's, I'm going to work on it fairly soon, and develop some packages.

[kirk]

ARP does make a conversion rocker arm stud for the 8100 , to install conventional BBC rocker arms or any aftermarket roller rockers.

[BTR69]

Good evening. Adger, I'm curious about your results with this, assuming you got yours programmed. I have a 98 3500HD, 454 with older whipplecharger. Swapping the computer out and the shop working on it says it's running like crap. They feel it's due to the stock tune not working with the supercharger. I'm looking for someone that can help my guys get this thing under control.

[Adger Smith]

After I bought my low mileage 2002 8100 WD 3500 I had some serious health issues and have just been using it between the house and farm. (no racing.. 44' LQGN sitting.. Just toating the Kubota) Soon after I got it in 2016 I noticed some issues with it missing and sometimes it died. I changed to the updated Crank position sensor and all problems went away. I have made a couple long trips in it. The longest from NE Texas/SW Arkansas to Minnesota. April of 2023 I delivered an engine to Ringgold Ga. while I was there I stopped at RED and Ronnie loaded down my 30 ft goosneck with 36 SBC engine blocks and several BBC blocks. It did well going back to Texarkana. Loaded and at Interstate speeds it averaged 9.75 MPG on the way home. I had a tune that ED Wright had sent to me, but had a comuter crash and lost it.. that was just after we had lost Ed. This truck really has served me well. It is nearing 58,000 miles on it. I still plan on doing some mods to it, but I just haven't taken the time.
Alan, I was wondering if you still had that 8100 engine and Trans I delivered to you. If anyone has an update on the tuning of the 8100 let's keep this thread going?

[BTR69]

I looked online into the Black Bear that Alan mentioned earlier in this thread. I've also been questioning others recently on this as well, and I've been hearing about 0411 PCM swap. Seems more folks prefer the 0411 to Black Bear. According to folks I spoke with today, it's more user/tuner friendly. I was advised to get a base tune, then get to a chassis dyno for a more specific tune. I'm pretty computer illiterate with these things, so having to rely on others for this project. Really hoping this gets the truck squared away.

[Greg West]

Kevin Winstead at Big Dog Tuning may be able to help.