Where did the boost go.

An older fella i know, used to work John Deere r&d years ago,
They put twins on an 855, and had the implement department make them a 60'wide plow (i can't remember what type), then they proceeded to rip the shock absorbing draw bar off the tractor. I think you need to do it Joe!
 
The factory twin turbo engine uses a HC3 and a T18A, Im not sure how a setup like this would work on a tractor, keep in mind this engine was rated at 475hp.

I would think a HT60 with the right size housing would be an ideal upgrade and good to over 500hp.
 
SmokinCAT said:
Wouldn't it not make any pressure itself if that were the case.
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There's still energy left when it comes out of the HT4, there's just lot of backpressure made by LP turbo which restricts exhaust flow out of HT4, making it work less efficiently. I doubt you have not even maxed out that HT4, why add another turbo ? Same fuel, more pumping losses = less power.
 
Joesixpack said:
Frankly I can't imagine how you lost top end. 45 pounds out of a compound arrangement HAS to be stronger that 38-40 psi on the single.
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Single usually makes more power with less boost than compounds. Compounds are only used to get wider operating range, not power.
 
SmokinCAT said:
It shouldnt be too hard, what were those engines rated at from the factory?
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360 and we've got the pump setup to about 400. While another 100hp don't sound like a lot it needs to be rated and setup for 100% duty cycle in a field tractor.

Leiffi said:
Single usually makes more power with less boost than compounds. Compounds are only used to get wider operating range, not power.
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Your kidding right? Compounds can be set up so many ways including max power just look at the Mod class pullers running compound's with with twin atmosphere chargers that couldn't possibly be run as a single stage for no money.

Now the way I understand it he's using the same manifold (high pressure) charger as he was running as a single.

Then he added a significantly larger LP charger.

If that's the case his power curve should blast up and through his old curve easily provided the fuel was there.

I agree that if he was already just on the line with fueling with the single then the pumping loss from compounds could cause a loss in power but in general with compounds you would still out power a smaller charger that was off its map making hot boost and he compounds making a more efficient charge.

500psi on the pump does suggest some larger injectors are in order.
 
Joesixpack said:
Your kidding right? Compounds can be set up so many ways including max power just look at the Mod class pullers running compound's with with twin atmosphere chargers that couldn't possibly be run as a single stage for no money.
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Here in Europe many pulling teams used to compete in SuperStock with 3 stage turbos, now they do ProStock with single turbo and get the same power and better reliability. Reason is compounds made so much pumping losses that it had to be compensated with extreme boost with no power gain. 3 stage had about 15-18 bar boost, now singles do about 7 bar.

Fastest Duramax here used compounds, he had over 7 bar boost when both were used but after he bypassed HP turbo almost 100% when LP started to make boost he gained more trap speed and quicker time, boost was only about 5,5 bar. So less boost made more power because of lower pumping losses. [ame="http://www.youtube.com/watch?v=BYUeb2pHr60"]incar 9.897@222.9 kph run - YouTube[/ame]
 
Well in super stock trucks on this side of the pond there are a couple single charger trucks pulling but they don't hang with the trucks taking the metal home. They don't on the dyno either. Guess those guys are not as advanced as the European folks.

As to the dmax I know of one Dmax that runs both faster traps and elapsed and he's running compounds. (Well actually a few)

Work personally with a race team here that just switched to a single and while simple and runs very well I know more power can be had on compounds but they can run nitrous if needed.
 
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I really think you are just plainly out of fuel.

The current QSX 15L 550hp tractors run HE551V 72mm compressor single varible vane turbo's for 550hp. Let alone an 84mm secondary and a 108mm primary on a 14L, that is a lot of air.
 
Joesixpack said:
As to the dmax I know of one Dmax that runs both faster traps and elapsed and he's running compounds.
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But it's about 500 kg lighter. The one in the video is running compounds too like I said but using them differently.
 
dvst8r said:
I really think you are just plainly out of fuel.

The current QSX 15L 550hp tractors run HE551V 72mm compressor single varible vane turbo's for 550hp. Let alone an 84mm secondary and a 108mm primary on a 14L, that is a lot of air.
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That same engine on a gen set uses a HX82 at 680 or so horse power.
 
Also notice it is listed as a 1500rpm engine.

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SmokinCAT said:
Here is a serial number to a QSX that has a HX82 Lenny. 79322777.
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Yes I found that too but our Holset importer showed me that billet HX60 with single scroll exhaust housing that was quite small, nr. 22 if I remember right. He said it was from 800 hp QSX industrial. I didn't found any QSX over 675 hp so maybe he mixed numbers, I think he meant 600 hp. HX 82 might work well and last forever at fixed speed at that hp level but must be very laggy if used in some road vehicle.
 
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