[jcus]

When I bought my coach, noticed boost was down, [about 18 psi max] so when I changed the air cleaner, looked at the compressor wheel and found several good nicks in the blades. Ordered a new higher flow one from ss60 and installed. Old exhaust pipe from turbo to muffler heat shield was in bad shape, so scrapped it, {I am still itching from the fiberglass!] Used 100 ft of 4 inch titanium heat wrap to replace it. Decided to get rid of the 55 gallon muffler, so bought a aero 5050 lx resonator and installed. Only problem is, it is a little longer than the old muffler so will have to modify it to use the side exhaust or find a flattened out tip to go straight out the back. 
Big difference! Cannot really make a before and after comparison, but now boost pegs at 30 + at full throttle at 1500 rpm and stays there till next shift.  Very happy with new power. Have to practice judicious use of the jake, as it has quite a bark at high rpm.
Only one change that bothers me, at 70 mph on the flats, 95 f. ambient, cac temp out was about 125 to 130 f., now it seem to run about 140 to 150. This seem high to me. Anyone seeing similar temps? or know where to get 5 inch to flattened out 4 by 6, or something close, exhaust tip?
Thanks,  Jim

[77newell]

Given all the air you are now cramming through the CAC I'm surprised the temperature isn't higher. On a hot day the temperature coming out of the compressor could be close to 400 degrees at full fuel flow. There is a temperature sensor on the intake manifold. I assume that if temperature became a problem the DDEC would dial back the fuel flow. As far as mechanicals go the materials can handle it on the output side if they can handle it on the input side.

[bestgenman]

The flattened exhaust tip is available from Newell and there is a post on this site about it's cost,  seems to me it was around $600.  They are hand made but not sure if by Newell.

I also had nicks on the compressor blades but did not change the turbo.  My restriction indicator was at the inlet to the turbo and always was way up near the red even after changing the filter.  The inlet offset was 5" so I changed it to 6" which required different hump hoses.  It was a pretty sizeable task since it took two 6" 45's hand fitted to the right angle with a small roll and a notch in the wall.  The end result was 30psi boost without restriction.  Little gain in fuel economy for all the effort.   The silencer was also replaced but not before it was opened and all internal baffles removed.  Now, the 60 can breathe and has plenty of power to push 60,000lbs.  Average fuel economy is 7.5mpg.

I did find a blanket manufacturer that is about half the cost of ATP and they have record of the dimensions, if anyone is interested.

[Richard]

Jim,

I flattened my home made tip in the vise. It was just standard 6" diameter exhaust tubing with a 45 in the middle.

It was an inexpensive experiment. I did find 6" chrome plated exhaust tubing that I will use next time, and just cut it off with a grinder. It appears my original was simply that. http://www.truckpipestore.com/6in-45-15x...nds-chrome or something similar. An ID/OD may be a better fit, but the 15" length is needed to get a straight cut across the back at a 45 angle.

[jcus]

Given all the air you are now cramming through the CAC I'm surprised the temperature isn't higher. On a hot day the temperature coming out of the compressor could be close to 400 degrees at full fuel flow. There is a temperature sensor on the intake manifold. I assume that if temperature became a problem the DDEC would dial back the fuel flow. As far as mechanicals go the materials can handle it on the output side if they can handle it on the input side.


Jon, checked with ddec 3 expert today, and he told me hyd radiator fan is  controlled by cooling water temp and intake manifold temp., and will derate if either temp is too high.
This makes sense as I also noticed cooling water temps remained low, suggesting fan was running all the time. Will clean cac and test again.
Jim

[Richard]

Jim,

The Detroit manual for the engine is listing 30 F as the maximum difference between ambient and manifold temp. I haven't found what happens if that is exceeded.

[77newell]

The cooling water temp has a lower "limit" determined by the thermostat in the engine. My 93 coach has a direct drive fan and the engine runs at the setting of the 180 degree thermostat in the engine regardless of outdoor temperature unless headed up a steep hill on a hot day, then it rises a bit.

So, if your engine is running cooler than the coolant thermostat in the engine you probably have a failed thermostat.

[jcus]

The cooling water temp has a lower "limit" determined by the thermostat in the engine. My 93 coach has a direct drive fan and the engine runs at the setting of the 180 degree thermostat in the engine regardless of outdoor temperature unless headed up a steep hill on a hot day, then it rises a bit.

So, if your engine is running cooler than the coolant thermostat in the engine you probably have a failed thermostat.

I believe my thermostat is already open at 180 f., and the fan goes to high at 199 and drops the temp to 194, then goes to low again till temp goes up to 199 again. But as my water temp stayed about 195, am thinking the high manifold temp was forcing the fan into high mode.

[Richard]

According to the DD manual for the Series 60, the tstats (both of them) start to open at 190, and are fully open at 205. My fan goes to high about 203-204, and drops to 194. This is when the engine has been running for thirty minutes or more at highway speed.

When I first start, the water in the radiator is much cooler, and when the tstats open, the temp drops to low 180s.

[jcus]

Probably not much interest to anyone, but found on ddec 3, intake manifold temp does not affect engine fan operation. It may derate the engine but can not really tell.
Because I have a less than perfect exhaust blanket, and a higher output turbo and low restriction exhaust, my intake manifold temp was running too high. [140+] According to Richard and DD, should be only 30 degrees above ambient.
This was a result of the hyd fan not coming on until water temp was high enough to trigger it. By that time, cac temp was too high. Was going to run wire to dash from hyd fan valve solenoid, so I could open circuit and allow fan to run.
Instead, bought $4 thermo disc that opens at 130 and closes at 115 and put in line with solenoid valve. Mounted it on the discharge of the cac. Now fan will come on for a short period and cool down intake air.
Probably not the best engineering practice, but can anyone see a downside to this setup?
Thanks Jim