I took the coach for a drive after installing the Aero AT5050 resonator (muffler, whatever). More growl, more giddyup and good for a grin. It sounded like the old "Mike boats" (landing craft) we used in Micronesia years ago and it was much more responsive to the throttle. I'm looking forward to seeing how it does on the long inclines. We hope to leave for the Northwest and Idaho in the next week or so, so this will give us a good idea about mileage, over heating, etc.
Did you gain any boost pressure on the intake side? Maybe 0.5 psi. I guessing that the turbo lag is improved and the soot generation period is reduced. Is the noise level reasonable?
Oh BTW a slash tip on the exhaust (45 degree) is way better than a straight tip. You can find these coefficients in ASHRAE for comparison. You can look up your engine exhaust rate on a Donaldson chart pdf online and determine the max exhaust velocity. All science no marketing BS. Not at the office now or I could dig up the evidence.
Defintely more fun to drive isn't it? The grin factor is for real.
Is your coach a red top 450 hp?
Looking forward to your report.
Played with mine from ca. across Colorado and Nebraska at different speeds for the last three days and 1,700 miles and got some numbers from my redtop 450.
It's a surprise, even after hearing the reports. Yes, it is a 450 ISM. Was not impressed before this.
After you have a couple hundred miles on your new exhaust system, crawl under there and check all the clamps. You may find some of them have loosened up a little due to heating/cooling cycle, and need to be tightened a bit. After that, they should be good.
Thsbkfull for the resonator references posted here as it got me started on my quest.
Then the posting about the VPMS gave me the tools necessary to delve into what foretravel built.
The resonator seems to have lowered the back pressure enough to drop the engines temp increases under a heavy load.
At the same time I changed the jammed on high hydraulic fan speed controller that foretravel speced to make the engine run as cool as possible with a quiet muffler.
Both pieces worked together as far as they thought.
The 180 to 199 thermostat change and the lowered back pressure seems to have lower the engines temp rise up steep grades and dropped 40 or more hp lost from the fan loads.
Towing at 70 across the rolling flatlands on I25 to I76 to I80 to Omaha from Pueblo resulted in a 700 mile stretch averaging 10 mpg.
One hundred miles towing at 75mph. Little wind. 9.3 mpg on the RMPG on the VPMS.
Last one hundred fifty miles was at 65.
Until a strong quartering wind came up towards the front right corner I was showing 11.5 mpg. Seriously.
Heavy wind dropped it at the worst to 10 mpg.
Boost at 75 was 10 psi.
Boost at 70 was 7.5 average
Boost at 65 was around 5.
Best RPMG for a low wind short stretch on flat ground at 65mph was 11.7.
Coaches long term Cummins memory for 120k miles shows 7.5 mpg.
My current total mpg since the two installations shows 8.4 mpg.
That includes going to the sequoia's, , local mountains. , Six hours in bumper to bumper traffic in LA, towing at 75mph up hills in New Mexico, wolf creek pass and such.
Passed numerous trucks and such up to the high 70's mph a bunch of times also
Tow is a Solara at 3,600 pounds.
Full water and 2/3rd's plus fuel
That's a lot of useful information, Bob. What engine are you running and what is the weight of your RV?
The boost numbers are amazing! The turbo was hardly working. We had both boost and pyrometer gauges in previous coaches and missed them when we got this coach, since I pretty much drove by those readings when climbing. In checking (on this forum), someone told me, unless I "hot rodded" the engine, there was no reason to have them. Hmm, I'd still like to have them, though, where I could mount them would be dicey. :-\
Cummins celect plus m11 built in oct 96 at 450hp and 1450 torque. Verified
Full GVW at 32,000 pounds. Plus the 3,600 pound car.
Was a dog compared to countless big engined high line coaches I have driven as a gear head Rv sales manager long ago.
First drive I said SOMETHINGS WRONG. Cummins shop service writer was courteous but had little interest in the details.
Cummins shop Foreman was/is very knowledgeable but this is a finesse thing. Lots of expensive steps and 4 years of incremental improvement and research.
Fixed
Sounds crazy BUT I think on flat ground,no wind, no tow and 60mph that the RMPG will be in the 12's
Love the boost gauge. Like you I drive with it. Shows wind loads and grade changes not visible.
Many times I have used a GPS program on my iPhone to verify altitude every so long just to see if I am going up or down hill in reality versus what it LOOKS like.
You can feel the coach pull up to the cruise set point. DW noticed that. Said it not do that before. At part throttle.
Pretty amazing fuel figures. My 32000 lb 99 320 never did better than 8.3 mpg on an extended trip with a 2500 lb toad.
Running about 70 mph. Actually mileage increased about .2 mpg with 500 hp upgrade. Kind of makes sense when the
silverleaf shows 50% load on flat ground for the 500 vs 60% load for the 450.
Have had many busses and motorhomes, and have never got near 10 miles per gallon.
The fan load I think was a big part of the bad mileage. Cummins shop foreman said the fan on high runs 50hp and heats up the hydraulic oil causing excess hydraulic fan motor wear and seal leaking from the pump and fan drives. Duh. Like alot here have experienced and posted.
At the same time I changed the jammed on high hydraulic fan speed controller that foretravel speced to make the engine run as cool as possible with a quiet muffler.
Where do I find this controller??
John
It's on every unicoach on the metal radiator piping visible when you lift the engine opening cover.
Has two hydraulic lines attached to it.
Expensive part. $700 range.
Someone posted a picture of the valve here with the hoses to replace a danfoss electric switch in anothef brand with these which are a piloted wax capsule ultra reliable unit.
Foretravel sourced the 180 degree unit from the source down south. Talked to the salesman personally a while ago.
Idle fan speed is 165. Full on at 180.
Rest of industry uses a 185 idle max speed at 199 degree unit.
The restrictive high back pressure muffler Foretravel used to be quiet probably got them to max the fan speed to minimize the frantic phone calls from owners saying "my temp gauge moved. My cars and trucks never move. Why does my coach overheat?"
Had a zillion of the same calls and explained this is ok countless times. And demonstrated it a hundred times in the desert with customers
So the lower hydraulic fan speeds are the true MPG booster? 25-30 HP saving would help quite a bit if 200 Hp was required for 65MPH travel........ I still have a hankering to hear that open pipe growl!!! Of course the cooler bedroom is a added plus.
David
Others input here may help define exactly what does what. Took me four years.
Should be easier as a lot of members here have done the resonator already.
My old Foretravel habits of helping to improve the coaches I guess has not gone away.
Versus keep it a secret and someday sell the coach for more money? Not my style.
I installed a 4" resinator and pipe using as few bends and large radius as physically possible to reduce back pressure. (Did this mostly for the sound but also for power increase). MPG increase is non existent after 2500 miles and I have no pyrometer so can't say anything about cooler EGT but here in the flat lands not a big concern anyway. Considering a 5" straight pipe as turbo spool time is way too slow. I have "enough" power as is, but more is always better and too much is the goal. 8)
Doc,what's your opinion on the bedroom heat aspect?
Hey John,
I think it is some cooler but 1500 lbs of 200 degree metal does radiate a lot of heat. Most of it goes up...by some strange coincidence. It is a mod I would do again. Hope that helps.
I do understand that heat rises, but I have a question.
A lot of posts mention the bedroom heating up from the heat cast off the engine.
Has anyone ever considered adding an electric fan to suck the heat out thru the louvered side? Maybe thematically controlled only when the ignition switch is shut off?
Just wondering.
Long ago I had foretravel outfit many new ORED's with Hayden automatic trans coolers set in the rear grille of the coaches.
Normally on a on off switch on the dash. Two fans.
Mike Grimes would remember what they were I think. But it was 30 years ago
We just fitter resonator then traveled 1800mile to Hwh , I would say it spins up quicker and the bed is cooler.
The huge oil drum muffler retains a lot of heat , that vacated space allows better air flow and cooling.
Happy with change
Been reported frequently before, but if helps someone decide will repeat...... we think the improvement to BR temp alone worth the change. The heat that had built and been held in the matters, and room, and now is not built there from the engine compartment, is a very real plus. We can now use just the from air when driving and the BR stays comfortable, when arrive easy to cool the little more desired.
Not sure if fans in the engine compartment are or are not equal to the resonator result, but the resonator also helps performance moving from a stop.
I have heard some private conversations though that removing the muffler may be a negative to the overall system but I could not follow the logic as I heard the discussion. Maybe others have reported, discussed, that elsewhere?
I to have concern.... My thoughts are the turbo spins up quicker, and I would assume faster rpms? But sounds like from previous posts here, the quiet, high restriction muffler was foretravels choice. I just have to believe cummins would have applications for this engine without mufflers....... Can a turbo over-spin? Turn too fast?
To answer your question,yes but at some point it stops pushing air ,think of it as a propeller on a plane at some point it does not
move air. The abscence of a muffer will not hurt anything.
Yes, but the
maximum speed of the turbo is not controlled by the exhaust pipe and muffler, or lack of same. Turbo speed is controlled (limited) by the waste gate. A properly functioning waste gate will allow the turbo to quickly spool up to some desired maximum RPM (boost pressure), and then maintain that RPM. Changing the exhaust pipe/muffler configuration downstream of the turbo outlet will not change the maximum RPM reached by the turbo, but it
might affect how quickly that RPM is achieved.
You will find few subjects more rife with disinformation than exhaust systems on diesel engines. Experts are to be found everywhere, yet sound scientific data is almost nonexistent. Most of the evidence supporting one modification or another consists of second-hand anecdotal stories: "My friend Bubba did this to his diesel dually with this astounding result...".
I think it is safe to say this: you can't
hurt your turbo diesel engine by removing the factory muffler. Beyond that statement, all else becomes a subject for debate. Everybody will have a opinion - you just have to pick who you want to believe. Good Luck!
When we got this coach last year, first thing I noticed was it had no boost gauge or pyrometer, where both my earlier coaches had them, and I drove by them on steep climbs. I called my expert, who does a lot of Banks hot rodding on coaches. He told me, "I don't care what you do with the exhaust system, but if you "soup-up" the engine for more power, you'll want the boost & pyro gauges."
With the Banks on our coach the waste gate was changed to a bigger head. This is part of their design in changing the effective power upgrade and I am sure they have researched what is needed very well. They do a lot of US Gov boat upgrading of motors for their offshore chases etc. Last time we were in Asuza at Banks a tech showed me one they were doing and it was a BIG power difference but he would not say what (confidential I guess)
I have both gauges and use them constantly along with VMSpc.
JohnH
Does the VMSpc show boost and pyro? If so, does it match the gauges?
Banks is a quality outfit. Have had their complete kits on two duramax's I have had. They do a lot of research and testing before selling their kits to make sure they are reliable. Some other tuners will give you more power but at the expense of engine longevity.
Jim
Dan, VMspc will show turbo boosts reported by the engine data computer. It also shows intake manifold temps. I am not sure what pyro is but if it didn't before the Banks install it will not after.
Roger,
I believe he means exhaust temp...He will probably need a Banks gauge for that, as that is what I have along with my VMspc.
John
Correct, I was wondering if the VMSpc shows exhaust manifold temp, like a dedicated pyrometer gauge does.
No exhaust manifold temp that I can see.
I sold Gale Banks his first diesel crew cab Chevy dually with a 6.2 GMAD engine. After his first mods he would engage his Hurst linelock to lock the front brakes then haze the rear tires. Cloud of tire smoke.
Impressive.
His full stainless exhaust system is on my v10 superduty as his his chip over ride and his Otto mind trans control.
130k miles it's fine. Really high quality stuff
Caflashbob have you considered writing up your engine mods in one post? Or, if you have done so I for one would love to study it.
John, I seem to remember hearing that the Banks kit replaced part of the turbo housing, was this the waste gate change of which you speak?
Banks Power | PowerPack (http://bankspower.com/magazines/show/540-PowerPack)
Ok.
5050xl Resonator
Donaldson blue foam air filter
Replace Winn system with a Parker/rancor
Replace fuel lines
Replace bad cam position sensor
Replace updated air pressure sensor
Adjust valves and injectors
Replace tires with fuel efficient Michelin zxa-3+
Rebuild alternator as it had a bad diode.
Add 270 watt solar to basically turn off the alternator driving.
Leave the solar set for 13.6 volts at the battery which matches the alternator output at the battery.
Replace the dynamatic 180 degree max on hydraulic fan control with an industry wide use 199 to lessen unnecessary hp loss.
The way foretravel built mine the fan was on high speed if the motor was at operating temp.
-50 hp versus at idle speed -15 hp?
90/100 psi in tires. Synthetic lube in front wheel bearings.
Partial transynd in trans.
My opinion is that the tires helped the most followed by the fan controller.
Easily noticeable that the coach has less rolling resistance.
Less retarder use where possible.
I have no idea if the mpg results I have seen are helped by my work and/or the engine has less power than others maybe because of issues still undiscovered?
Power is better especially the torque in the upper gears.
Also possible that the engines computer alters the power from cold to warm.
Possible that the overly on fan control caused the computer to hold back some power.
Would have to change the controller back to maybe see.
Or is it just the tires and exhaust?
Or just the fan?
Hard to know.
Works well enough now I am ok.
Need feedback on boost psi on others. Mine used to top out in low altitude small grades at 28 pounds now hits 31 or so revved up in fourth
Expensive resonator job as the dealers guy ordered specific curved sections and welded everything beautifully.
Versus more flex tubing? Unknown.
I would trade the mpg for more power but not really needed just wanted.
Hope this helps. The exhaust really helped free up the motor