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H1 Hummer Cummins Swapped

Droning can be eliminated by using a twist core short muffler just after the down pipe or a long twist core further down the system......only other option is too go custom to eliminate the drone.

Doing the math 40" tires seem to be a better choice.......however; this is dictated more by where you normally operate that Hummer.
 
Some places off road and yes hiway, the 40" helps. But hummers already tend to eat upper and lower ball joints about twice as fast as pickups. Idler arm and pitman arm are on the menu even more, as it isn't just the 37" height but the 12.5" wide tread on the ground on all four corners. When you go to 40", most are 13.5" wide. The added leverage does not help these components any. Then getting a small lift so the taller tires don't hit the hood on full movement is also needed as the 37" barely clears.

If the trans/tc isn't right, fix that before throwing on bigger tires imo. There is a bunch of guys that went to 40s, and none messed with their trans or tc to do it.

I am all for anything to quite the ride, these rides are loud being a huge box of aluminum.
 
FellowTraveler said:
I'd bet the torque converter has to high of stall, on a Cummins as you modify for power for a DD the stall speed should be lowered ans yes there are arguments to the

I run a 1.2k converter and when its locked I stomp on the throttle and it stays in lockup and the Burb just halls a_s, then again it's a highly modified 47RH transmission.
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Very helpful. Partly I'm just getting educated on the role of a TC and what its for. I've reset the lockup parameters to remain in lockup when I mash the throttle instead of breaking lockup after 70% throttle. Big difference. It stays locked, builds boost and power. Thanks!
As well in my setup menu I had ticked the 8 cyl. Box. Just not used to it being a 6cyl yet...not sure what it affects but possibly 25% out in calculations for the controller somewhere...
Good news about the drone too. I thought it was driveline but exhaust does sound 56303more likely. Room is tight but Ill see what can be fitted under my feet pre muffler.
Just a funny pic of how crooked the engine sets. Stock crookedness. Lol
 
Sand said:
Very helpful. Partly I'm just getting educated on the role of a TC and what its for. I've reset the lockup parameters to remain in lockup when I mash the throttle instead of breaking lockup after 70% throttle. Big difference. It stays locked, builds boost and power. Thanks!
As well in my setup menu I had ticked the 8 cyl. Box. Just not used to it being a 6cyl yet...not sure what it affects but possibly 25% out in calculations for the controller somewhere...
Good news about the drone too. I thought it was driveline but exhaust does sound View attachment 56303more likely. Room is tight but Ill see what can be fitted under my feet pre muffler.
Just a funny pic of how crooked the engine sets. Stock crookedness. Lol
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I keep mine locked up as much as I can not, too, and it made a huge difference. I'm glad to hear it's working better for you now. At some point you'll still likely want to put a tighter TC in it so it's more responsive before the converter clutch locks.

Regarding the crookedness: I went to the shop @LowRam works at a couple weeks ago and got to see a couple of their Hummer conversions that are in-process. I had never seen a Hummer that close or in that state of togetherness before. I too was surprised at how crooked the engine sits in the engine compartment, but it makes sense for how the driveline routes through the machine.
 
Sand said:
I can adjust the % of torque converter lockup. Should I dial it up?
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I'm not sure about that. I'm afraid you'd just be burning up the clutch, but I can't answer that with 100% certainty. Stall speed and percentage of clutch lockup are 2 different things. I'd have to look at how I have mine programmed, but I'm pretty sure mine goes straight to 100% lockup at the speed/rpm that I have it set to lockup. Like you, I just kept messing around with it until it worked close to the way I wanted.....knowing that the stall speed was still wrong for the set up. There's nothing I can do about the way first gear feels until I swap the converter, but for 2nd through 4th, I lockup the converter as soon as I can when I'm giving it more throttle. I'd love to keep it locked during shifts even, but I'm afraid of parts scattering if I was to do that. I'm not sure if this answer is helpful to you or not.
 
I’ll keep mouth shut on when to lock/unlock and learn also.

For thise that never seen the engine/trans angle Yeah, rather than both driver and passenger having no leg room, they angled it to just make the passenger hate life on long trips. Driver’s seat is nice and cozy.

I have wondered how much it could be modified to give the wifey more room. I might dig into it after all this other mess is done on mine. The cummins should allow even more room to open up...?
 
Will L. said:
For thise that never seen the engine/trans angle Yeah, rather than both driver and passenger having no leg room, they angled it to just make the passenger hate life on long trips. Driver’s seat is nice and cozy.

I have wondered how much it could be modified to give the wifey more room. I might dig into it after all this other mess is done on mine. The cummins should allow even more room to open up...?
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If I remember correctly, @LowRam said the starter location on the Cummins actually made it tight to fit it at the factory angle, but it was doable. One they were working on now had already had a conversion done to it when they received the truck to work on - when the other person did the conversion they messed with the angles and it had a pretty decent vibration due to it. There might be an opportunity to change the angles some, but one would have to be sure to not screw something else up in the process.
 
I managed to get within a degree or 2 of the stock angle with lowrams advice. I'm happy with the result. There are so many components engineered in a really tight place. Some say its stupid. I say genius. The 6 is longer than the 8 and just highlights the skewed placement more acutely. Its funny.
 
Sand said:
Very helpful. Partly I'm just getting educated on the role of a TC and what its for. I've reset the lockup parameters to remain in lockup when I mash the throttle instead of breaking lockup after 70% throttle. Big difference. It stays locked, builds boost and power. Thanks!
Click to expand...
This is where high end multi-clutch converters shine.
 
I'm in full lockup mode now after a delay of about 3 seconds in 3rd and 4th. Much better. It locks which feels like its gone into 5th gear and then stays locked. You can pour on the fuel, the boost guage hits 30+ and the whole crazy tractor just keeps building speed. Even uphill. It's great. A really different feel to the 6.5 TD. Whole different truck now. It runs about 23 - 2400 rpm at 105 -110 kph (65 mph). I've stopped trucking trailers around for a bit and should have some MPG numbers tomorrow. I'm really hoping for higher teens as my 6.5 never really did much better than 14mpg imperial. Which is average for a small block 350ci 1/2 ton GMC mid 1990's - so not bad really...
 
Sand said:
I'm in full lockup mode now after a delay of about 3 seconds in 3rd and 4th. Much better. It locks which feels like its gone into 5th gear and then stays locked. You can pour on the fuel, the boost guage hits 30+ and the whole crazy tractor just keeps building speed. Even uphill. It's great. A really different feel to the 6.5 TD. Whole different truck now. It runs about 23 - 2400 rpm at 105 -110 kph (65 mph). I've stopped trucking trailers around for a bit and should have some MPG numbers tomorrow. I'm really hoping for higher teens as my 6.5 never really did much better than 14mpg imperial. Which is average for a small block 350ci 1/2 ton GMC mid 1990's - so not bad really...
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Lockup points as long as the converter clutch (s) can handle it makes for a much better DD w/Cummins. My controller is primitive for the LU/OD on the 47RH compared to your setup once you finalize the trans tune you will be stoked great conversion there.
 
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I had it built. My converter builder says that anyone advertising a really low stall 4L80e converter is lying. They dont make components to put together a 1200 rpm stall 4l80e.
He put in a billet piston, HD clutch, and set the clearances tight on the 2 halves. Then he custom tweaked the curl on the ends of the lowest stall turbine available(1600 rpm I think) and tig welded them all back in place. He estimates its about a 1400rpm unit now. The best that can be done with a 4L80e.
I do have an allison 5sp from a duramax that was nearly free. Im a bit swap exhausted but may make a 6sp out of it in years to come if my 4L80 dies.
 
Sand said:
I had it built. My converter builder says that anyone advertising a really low stall 4L80e converter is lying. They dont make components to put together a 1200 rpm stall 4l80e.
He put in a billet piston, HD clutch, and set the clearances tight on the 2 halves. Then he custom tweaked the curl on the ends of the lowest stall turbine available(1600 rpm I think) and tig welded them all back in place. He estimates its about a 1400rpm unit now. The best that can be done with a 4L80e.
I do have an allison 5sp from a duramax that was nearly free. Im a bit swap exhausted but may make a 6sp out of it in years to come if my 4L80 dies.
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Here is a company that does make its own components for their converter offerings.......

Triple clutch and all the goodies to include 1.2k stall.

 
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