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Taking the 12.7 to 600hp
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I have a friend with a S-60 in his Kenworth. Owner-Operator. He’s hot rodded the S-60. Fancy computer controller, bigger injectors, bigger turbo, and probably more. Really likes it when he’s pulling a full load he can turn the fancy computer up and get more power … accelerate better, climbs hills in a single bound, etc.
To hot rod the S-60 in a Prevost, I’d be asking how much HP, torque, and heat can the Allison transmission take? Does it need a bigger tranny lube cooler?
I’d be asking how much more heat the S-60 will put out and will the radiator/CAC be able to get rid of it. Like any internal combustion engine there are only a couple of ways to get more power. Fine tuning and machining of the internals to maximize efficiency. Then its a matter of more air (bigger turbo) and more fuel (bigger injectors). The extra fuel creates lots of wasted heat which has to be gotten rid of. It would be frustrating to spend $10,000 (I’m just guessing guys) on a hot rod deal and find out I can’t use it for more than a few minutes because the engine overheats.
Finally my friend with his now 600 to 700hp S-60 is driving his 80,000 tractor/trailer through two (2) differentials. We drive our 48,000 to 52,000 pound coaches (plus a toad or trailer) through a single differential. How much stress and strain can that single differential take? Would it take a 52,000# coach plus a 12,000# enclosed trailer running up the mountain at 75mph (or even 70mph) without complaint? I wouldn’t hot rod a S-60 without having a reliable diff temp gauge to watch. And then would use of the hot rodding be limited by the temp of the differential?
Please keep us posted on your process and experience.
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I have a diff temp gauge on mine and usually gross at 65-70,000#. I GUARANTEE you’ll need a diff cooler installed to use 600HP for any length of time.
JON: I have no problem at stopping @ 75 mph. I simply toss out the anchor I carry under the driver’s seat. You guys with little toll windows can’t do that..
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None of us will have a problem stopping at 70 or 75.
But at that speed and distance in excess of 450 feet, the guy in the car ahead that can stop in somewhere between 140 and 180 feet might have a problem.
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Joel: What kinds of differential temps do you see without towing to big of stuff on the staight and level? At what temps do you start to become concerned?
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Without towing anything (I’m either single or trailer, no toad) it’s not an issue generally. Temps go up depending primarily on speed and ambient temp when I’m towing. My max speed is 75 and to hold no more than 260 I sometimes have to reduce speed to 70 or even 65. You can easily exceed 300 at 75 with a load and high ambient. I run full synthetic and have found it necessary to change every 20-30K miles.
Trans is not an issue except for retarder use.
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Im done. Im not messing with it anymore. Ive played this game plenty of times with my big rigs, cars, diesel trucks. I was hoping it was over engineered and its not. Its engineered for 475hp. When I order a Peterbilt with 600hp, its the same engine I get when I order 500hp, the difference is all down the line behind the engine. I leave it set to 600hp and just drive the gauges to keep it within tolerance. I spent about $1k on a bigger turbo, and $1100 on the tune, so its no big loss. The 14L is a different beast, different internals, more displacement, among other things. In the future I may drop in the 6067HK60 which is the DDEC 4 pre-egr 14L that in theory bolts in. Ill save that for another time though. Im currently in the middle of the battery swap and some remodeling on my house, so Ive got plenty of stuff to waste time and money on.
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My previous post of 6/22 at 8:31 was based on 30 years of listening to owners who just had to have more HP.
And for 30 years those that did that never were able to use the added power to do sustained long hill climbs. Few if any admitted adding HP is not as easy as it sounds.
Hats off for telling the net result. With luck future owners who want more HP will learn from this.
Now we need to get the folks who think they can carry a heavy motorcycle off the rear of the coach to understand how doing that is going to do hidden damage to the frame.
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A couple thoughts here.
First off a larger engine will run cooler than a smaller engine at any given power level because there is more air moving through the engine. So a 14L (non EGR) engine would run cooler than the 12.7. Getting 600HP from a 14L engine is like getting 544HP from a 12.7L engine, all things being equal.
Next, an engine will run cooler at higher RPM than lower RPM for a given power level. Higher RPM = more air flow through the engine = lower temperatures for a given fuel rate (HP). Making 600 HP higher up in the RPM range is quite different than lugging it at peak torque.
And if the Prevosts are like other Allison installations I’m familiar with, the transmission is cooled by a heat exchanger built into the bottom of the engine’s radiator. You can dramatically improve the cooling capacity of the system by adding a separate transmission cooler to the system and not using the radiator’s built in heat exchanger. This will allow both the engine and the transmission to run cooler. However, there can be an issue with the transmission running too cool in some situations. The great thing about the radiator heat exchanger is that the transmission is up to temp when the engine is up to temp. With a separate cooler, that isn’t necessarily the case. I’m not sure how the B500 regulates its temperature. One way around this is to use both an external cooler and the built in heat exchanger, in series.
One way to improve fuel economy, decrease cooling issues and increase power to the ground would be to replace the B500 with an automated manual transmission, such as the Ultrashift. I’ve seen this done before to great effect. Mechanical transmissions have much higher efficiency than automatics, even when the automatics are in lockup.
I wonder if coaches equipped with transmission retarders get a larger radiator that could be swapped in for more cooling. Maybe not though because if the bus is going down hill and using the retarder, the engine load is basically zero and not requiring any cooling.
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Is there a document that outlines what parts make up various DD S60 engines ? Piston, turbo, injectors, ECM program, etc. ?
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“Instrument panel picture attached for reference.”
Pyrometer is sub 900F and boost is 30ish PSI. You must be backed out of it at this point ?
Water temp maxed out at 220F ? Where is this temp being measured ? Have you ever looked at what DDEC is measuring ?
Is the TC locked when climbing like this ?
Like I said above, separating the B500 cooling from the engine cooling would do wonders here.
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“We never put a probe on the inlet side of the turbo, if you fry it or break it off for whatever reason the only place it’s going is thru the turbo.“
Pre turbo EGTs are what matter on a hard working diesel engine and post turbo EGT measurements have little or no correlation with pre turbo temps because the temp drop across the turbo depends on a large number of factors.
You’ll fry a diesel engine before you fry a pre turbo EGT sensor. There should be no reason to break off an EGT probe when servicing an engine.
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Pre turbo Pyrometer is the true accurate EGT of any Turbo application gasoline or diesel. 2 60 series coaches over 20 years, 3 8v-92 coaches , Delaney & Alf built 92’s , 4 Ram pickups 5.9 & 6.7 Cummins, nothing stays stock. All ran pre turbo pyrometers, 0 failures…I’ll stick with success making horsepower .
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I flew various turbocharged airplanes. The probes were near the turbine inlet, thus the name TIT “turbine inlet temperature” probe.
Probes going thru the turbo wasn’t a problem. -
“Probes going thru the turbo wasn’t a problem.”And gasoline exhaust temps are way higher than diesel exhaust temps.1999 XLV X-6872, liberty #440
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You can argue until the cows come home what side to put it on.
My experience from the old truck days was we never got a new truck with it on the inlet side.
Over 850 3406B motors in Pete’s and they were always on the down side.
Like they say, do what you want.
Later
bv
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