Builds Big Red Toy (16 Viewers)

[GLTHFJ60]

I've done 1200* for 3 hours no issues at highway speeds. I just can't find a clear answer anywhere on what's the highest safe sustainable temperature I can run at which won't cause any issues down the line.

That's because Cummins doesn't publish EGT numbers. You won't find concrete numbers anywhere.

In my opinion, 1200* is the highest continuous temperature I will run. I've run 1200-1300* (trying to keep it at 1200) for as long as 8 hours towing on the highway before, no problems. During some of those tows, I got distracted and let the motor hit 1500* EGT. When I noticed how hot it was, I jumped right out of the throttle, no side effects. Motor still runs like a scalded dog.

 

[The Phoenician]

That's good to know. I was pretty much doing 1200 going up the mountains in New Mexico. Now Mike has me dreaming of compounds. Need to start researching what goes well with an hx30.

 

[GLTHFJ60]

HX35 goes well with an HX30. Mike has a WH1C and a volvo turbo if memory serves (very, very similar to a HX30/HX35 setup)

 

[boots4]

The WH1C was the original plan to couple with my original TD04HL-16T but I moved onto a HE351VGT for my big turbo that I picked up when they were cheap. I guess you could say it's more like a HX40. I build up the small turbo to basically a TD04HL-19T with a 7cm housing and have the HE351VGT set at a 15cm housing. I'll continue to play with balancing/experimenting how I want these two to share the load but right now the HE351 is doing more of the work and is working well this way.

I keep playing with more and less fueling and find I like it in the 50psi range. I cruise 60-70mph at 650-800F EGT. Pushing it I have a hard time getting to 1100F and find I don't pay attention to the pyrometer like I used to. If I tow a load sustained up a hill then I can get up to the 1200F range but then I'm towing much faster than I probably should and back down anyways. At the moment I'm having a hard time keeping my small turbo to intake tube connection holding together. At the very least I'll be getting a better hump in the metal tubing for the coupler to bite into but I may end up going with a v-band connection. Silicone hose connections just aren't holding up to this kind of boost and temperature.

As far as fitment when I see how these little 4-cylinder ricer beasts fit crazy stuff under their hoods it helps me know anything is possible. My HE351 is a big bodied turbo, a different choice wouldn't need as much room but things would probably need to be adjusted to fit. That's the rule of "custom". Changing one thing affects other things.

 

[GLTHFJ60]

Drool.

Someday I'll compound with an HX40 to compliment my Super HX30.

 

[The Phoenician]

The WH1C was the original plan to couple with my original TD04HL-16T but I moved onto a HE351VGT for my big turbo that I picked up when they were cheap. I guess you could say it's more like a HX40. I build up the small turbo to basically a TD04HL-19T with a 7cm housing and have the HE351VGT set at a 15cm housing. I'll continue to play with balancing/experimenting how I want these two to share the load but right now the HE351 is doing more of the work and is working well this way.

I keep playing with more and less fueling and find I like it in the 50psi range. I cruise 60-70mph at 650-800F EGT. Pushing it I have a hard time getting to 1100F and find I don't pay attention to the pyrometer like I used to. If I tow a load sustained up a hill then I can get up to the 1200F range but then I'm towing much faster than I probably should and back down anyways. At the moment I'm having a hard time keeping my small turbo to intake tube connection holding together. At the very least I'll be getting a better hump in the metal tubing for the coupler to bite into but I may end up going with a v-band connection. Silicone hose connections just aren't holding up to this kind of boost and temperature.

As far as fitment when I see how these little 4-cylinder ricer beasts fit crazy stuff under their hoods it helps me know anything is possible. My HE351 is a big bodied turbo, a different choice wouldn't need as much room but things would probably need to be adjusted to fit. That's the rule of "custom". Changing one thing affects other things.

I spoke with the guy who replaced my gear housing cover. He's done a couple of compounds on the 6bt cummins, he was excited that I even entertained the idea. He's working on one right now that's putting out 75 psi. He recommended studding the head and doing something with the O rings so the gasket doesn't blow.

I seem to remember you had issues with your freeze plugs, how did you end up fixing that problem. I'll go through your thread again, but I'm not near my desktop at the moment.

 

[boots4]

Yup, I've been popping the freeze plugs out. A coolant bypass system was needed on my engine to relieve the pressure at the back of the block which is the most common place for freeze plugs to pop on the cummins. I also replaced the side and rear plugs with a different design.
I did just re-seat my front freeze plug about three weeks ago since it had started leaking too, but that was easy since I didn't have to pull the engine to get to that one. So I've been all around the block now.

Studs are a must to reliably hold the head down on any thing north of ~45psi or so. For me I torqued my studs to 135 ft/lbs the last time with a standard head gasket and it's been holding up fine; I was religious this time about re-torquing the studs several times. If I was going to play in the 60psi or more game I'd get my head set up for o-rings. A groove is cut in the head around the cylinders and a metal wire sits in the groove and when it's clamped down on the block with studs you can safely handle higher boost.

 

[The Phoenician]

Dang, now this gives me a second dilemma. I want more boost and less egt but I want this to be a really reliable rig. Don't want plugs popping out when I'm 500 miles away from home.

Do you remember how much your egt dropped by when you compounded the turbos?

 

[The Phoenician]

So, I'm beginning to dream a little too much about twin turbos. You guys think there's enough room here?

I plan on keeping the original turbo on there, so I just need to figure out how the larger one will fit and what needs to be rerouted.

 

[KWalkerM]

Yes, and if their isn't I know of a solution, Sawzall the hood. I know of a couple rigs (4runners/minitrucks) that have turbo cut outs on the hood.

In all seriousness, it does look like you have room next to the block, just move a few hoses and probably your AC compressor if it really came down to it.

 

[GLTHFJ60]

Bro, there's always room. If you have to, cut a hole in the roof

 

[The Phoenician]

I was thinking of having the hood cut open if I had to, but then that opens up other issues like dealing with heavy. time to start saving and gathering parts and figuring out a way to justify it to the .

Honestly my only hesitation now is the freeze plugs. I don't have the patience or the know how that @boots4 has.

 

[KWalkerM]

In the words of Domininja @ Valley Hybrids "The hard part about using a sawzall is once you start cutting stuff off, its hard to stop"

Screw it just put a blower on top plus the turbo, that's legit right? Or just ditch the hood entirely and don't drive when it rains

 

[The Phoenician]

In the words of Domininja @ Valley Hybrids "The hard part about using a sawzall is once you start cutting stuff off, its hard to stop"

Screw it just put a blower on top plus the turbo, that's legit right? Or just ditch the hood entirely and don't drive when it rains

I started this rig so it can withstand the zombie apocalypse. I would have failed miserably is rain is what stops it .

 

[KWalkerM]

I started this rig so it can withstand the zombie apocalypse. I would have failed miserably is rain is what stops it .

Then wheres the snorkel?! haha

 

[The Phoenician]

 

[KWalkerM]

I stand corrected

 

[boots4]

Yes, there is plenty of room to keep it all under the hood in your set up. One way is to get a 6bt manifold and reduce it to 4 runners (like I did) and mount your HX30 up high. Then run a HX35 underneath it. Route and plumb lines where they fit. Another could be running the big turbo up top and keeping the small one where it currently is. A spacer could be used to drop the small turbo down lower to get you more room for the big turbo up top if needed. It all depends on how skilled your fabricator would be, but there is definitely room to get another turbo in there.

You'd be looking at buying another turbo (HX35 is a good choice for this combo), new/modified turbo oil drains, another oil supply line, potentially different exhaust manifold, exhaust re-route and parts, intake re-route and parts(might upsize to 4"), gaskets and other fittings, bracing, heat wrap, another boost gauge.

It's not only that I dropped EGTs but I also gained a decent amount of power. I'm probably in the 250-300hp and 500+ftlbs range. EGT's will definitely be lower but will depend on how you tune it.

This is all my opinion but if you do decide to go down this route the accompanying upgrades will depend on how much more you want to push it. If you want a bunch more power then more additional upgrades will be needed. If all you want it a little more and planning to stay at 40psi total or lower then fewer additional upgrades would be needed.

Additional upgrades to consider:
head studs
better freeze plugs
coolant bypass
free flowing intake (air filter, etc.)
o-ring the head if you're going for higher boost

Tell your wife I'm sorry for mentioning it.

 

[Pacer]

Maybe you can tweak the timing a little?Possibility shed some EGTs and save a bucket of ca$h...

 

[The Phoenician]

Maybe you can tweak the timing a little?Possibility shed some EGTs and save a bucket of ca$h...

I thinking about advancing it a little to see if it makes a difference. I found out I'm ordered back to the sand box soon, so I may just accumulate parts until I return.

In the meanwhile, my 18 dollar catch can came in.