| Author | Message | ||
| Peter River (Whitebus)
Registered Member Username: Whitebus Post Number: 11 Registered: 4-2009 Posted From: 204.62.111.51  Rating: N/A |
logic tells me that an engine that has breathing restriction would perform poorly. when I first picked up my bus, the tailpipe was bent in the middle (result of going over a dirt pile?) to about 75% of its size. I cut that piece off, replaced it with a straight 4" dia pipe, and suddenly the unburnt black dust that used to stain the back of the bus disappeared. Now I am looking to the intake part of it. Right now, it has this monster bus air filter. It's looks somewhat like your basement water heater. Huge cylindrical thing. Curiously, the ~5" dia intake into the turbo is fed by an anemic small airbox (pre filter?) with a opening that looks about 6" square, with a plastic grill on it (further restricting airflow), near the roofline. I am thinking either opening up the line between the airbox and filter, or bypass the huge filter altogether (later on, because I spent $200 on this filter recently) and opt for one of my own design (probably involving the largest K&N filter element in a free breathing box of my own design, fed through the bottom to minimize blockage. does it make sense to you? ever mess with your own intake system? | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 251 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
Peter DON'T RUN WITHOUT AIR FILTER. No faster way to destroy the engine. The 5" between the filter and the turbo is normal but if you have a turbo that will accept a 6" go for it. The air inlet to the filter should be as open as possible. I had overheating problems with the orginal inlet but when I opened it up things cleared up. Better breathing for the engine is always good. Just remember that the more air in the more air you have to exhaust. Bill | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 198 Registered: 1-2007 Posted From: 208.81.157.90  Rating: N/A |
Improving the breathing can make a lot of difference. Putting dual exhaust and a modern carb on our first bus helped a lot. Big gas V6. Sometimes the intake design has a silencing effect. The intake on a diesel can be pretty noisy. May not matter in a bus. K&Ns do breath better but some feel at the expense of poorer filtering. Keep it serviced if you use one. My buses spend enough time on dusty roads that I want all the filtering I can get. It is good that your intake is up high. I would not change that. Another thing to consider is water intake when it is raining. A quick response to another post. First bus is a 35 footer and we like the maneuverability so much that the second bus is too. Good luck Don 4107 | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 807 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Pete, A couple of thoughts. K&N filters advertise more flow, but at less filtering efficiency, as mentioned above. A 5 inch round pipe has about 19 1/2 square inches of area. A six inch square opening has 36 square inches. Air doesn't like to turn sharp corners, so if you modidfy your intake, be sure to use long-radius elbows. An indication of insufficient intake airflow is black smoke under full power. If no smoke under full power, there is enough air available to properly burn all of the fuel injected. HTH, George | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1425 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
If you are concerned about air restriction, get a restriction gage and install it. See what it says first before you take a saw or torch to anything. Weigh your coach. It takes good increase in horsepower to see a real improvement, especially on hills. | ||
| Peter River (Whitebus)
Registered Member Username: Whitebus Post Number: 15 Registered: 4-2009 Posted From: 204.62.111.51 Rating: N/A |
actually it came with the restriction gauge. it went to 7 out of 10, that's why I replace the air filter. unfortunately, it didn't do anything to alleviate pressure, and on a skoolie group, I was told that the gauge may be out of spec. | ||
| Marc_bourget (Marc_bourget)
Registered Member Username: Marc_bourget Post Number: 11 Registered: 10-2006 Posted From: 64.142.42.176 Rating: N/A |
Restriction Guages - I've seen these advertised for $25 or so. Got a couple-3 at the local "pick-n-pull" wrecking (er, parts) yard for $1.00 ea. These things aren't that precise, but good to the extent that they will show it's time to change the filter. Would be easy to build a manometer for more accurate data, but you'd have to open the engine bay and look while revving the engine once in awhile. Think they came off a late 90's GM car. FWIW | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 225 Registered: 12-2000 Posted From: 24.164.20.23  Rating: N/A |
Peter, what did I tell ya? An 8.3 is in your future. lol In the meantime Banks has a lot of options for the 5.9. Take a look: http://bankspower.com/app/index/2 BTW, I have one in my Dodge P/U and I love it. (The 5.9, not the Banks) | ||
| macgyver (91flyer)
Registered Member Username: 91flyer Post Number: 366 Registered: 11-2004 Posted From: 74.193.225.134  Rating: N/A |
Since this hasn't been mentioned, I'll mention it now... The colder the air going in, the better the engine will run... Cold air = dense air. Dense air equates to power. That's why some sports cars with big turbos have an intercooler after the turbo... to cool it down after it's been compressed... Also, the warmer the air going in, the higher the risk (and probability) of detonation, which will literally tear your engine to itty bitty pieces. Instead of a K&N, perhaps you should install a bigger air box with a bigger standard filter... Increase in surface area of the filter means that the restriction on the airflow is reduced considerably.... Perhaps you could experiment with a large intercooler after your turbo... Ducting air in from up high, away from the engine... Don't use the same air stack as your intake though... Chances are very low that any fan you could use would overcome the force of the engine drawing it's breaths. My 8v71 isn't turbo... Though, if it were, I'd be looking into this for myself, simply out of curiosity.... Don't use a K&N... They're good for cars, but I wouldn't trust them for our big engines. They require constant cleaning when used in a car... They plug up fast, and they're a hassle... Just owning and operating a bus is hassle enough... No need to add more gas to the fire! ;) Just my thoughts on the subject... -Mac | ||
| doug yes (Dougg)
Registered Member Username: Dougg Post Number: 82 Registered: 1-2007 Posted From: 174.131.116.148 Rating: N/A |
On the 102-D's isn't the charge air cooler before the turbo? To suck in cooler, denser air then compress it with the turbo. The truck power guys pipe recommendations: straight as possible and big as possible and source it from high cool air. | ||
| Bill Laird (Billaird99)
Registered Member Username: Billaird99 Post Number: 15 Registered: 4-2008 Posted From: 24.163.34.244 Rating: N/A |
Just a bit of a clarification, intercoolers (the ones I've seen) normally are before the turbo. They do allow a denser/cooler air flow into the turbo where it is then compressed and sent into the intake tract of the motor. Bill | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 808 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Sorry, But the charge air coolers have to be AFTER the turbo, otherwise how would they cool the air inside the [AFTERcooler] by the same temperature air blowing over the outside of it? (INTERcooler=between, as between the engine and the turbo.) (AFTERcooler=after the turbo, same thing.) Compressing the air heats it, then it has heat to give off to the ambient temp air going over the inter/after/charge cooler, and then goes into the engine cooler and denser! G | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 649 Registered: 7-2006 Posted From: 75.211.121.125 Rating: N/A |
 ...atta boy, George! RCB | ||
| Bill Laird (Billaird99)
Registered Member Username: Billaird99 Post Number: 16 Registered: 4-2008 Posted From: 24.163.34.244 Rating: N/A |
I stand corrected. Bill | ||
| Marc_bourget (Marc_bourget)
Registered Member Username: Marc_bourget Post Number: 12 Registered: 10-2006 Posted From: 64.142.42.176 Rating: N/A |
Add on and/or Turbo'd engine conversions are problematical. Lots and lots of $$ is spent by OEMs making these systems work well. It's highly technical and not for a shade tree mechanic. Adding a Charge Air Cooler to a bus where none was originally provided can raise many, potentially fatal,(to the engine) issues. Positioning is critical. There is a maximum discharge Temp (aka inlet temperature). The tubing curves and routing can have a big effect on whether cooling sufficient to prevent detonation is available to the engine intake. Cobbing something together could be a recipe for disaster. Be careful! This is the part of bus converting that approaches Rocket Science. | ||
| Ralph Peters (Ralph7)
Registered Member Username: Ralph7 Post Number: 4 Registered: 3-2004 Posted From: 66.59.120.99 Rating: N/A |
When talking DD , compression is lower on turbo 17-1 vs 18-1, turbo has water cooled after cooler under blower, and I think the blower runs slower. Hopefully in late May my 8-71 TA will be in the bus, and also installing a Jake brake. Also on a 4 cycle turboed you must have a aftercooler temps are super hot, pistons are aluninum, but 2cycle are cast iron. YES 8-71and 8-71TA have some big differences. My 8-71with 70 injectors is about 325hp the 8-71TA is 350hp however on hills it will smoke less but will need to watch the heat. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1428 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Detonation? That won't happen till the moment that the fuel is injected, regardless of the temperature. You may be thinking of a gasoline engine where detonation is like the spark plug firing, but at the wrong time and can destroy an engine if it is severe enough. Lowering the heat from turbo outlet to engine improves power and fuel economy. Also lowers piston temperatures, although the amount of fuel injected is also proportional to combustion chamber temps. Some have used propane injection on load to get more power and the cooling effect of the propane can provide some of the benefits of an intercooler. Not advocating it's use, but some are happy with it, although it adds complexity and creates another item to maintain. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 78 Registered: 1-2006 Posted From: 66.218.33.156 Rating: |
K&N filters do NOT filter out all the dirt (this has been proven in tests with PU trucks with Diesels). Keep that big air cleaner and use a quality name brand filter element. Good Luck, TomC | ||
| Marc_bourget (Marc_bourget)
Registered Member Username: Marc_bourget Post Number: 16 Registered: 10-2006 Posted From: 64.142.42.176 Rating: N/A |
John, You're correct, but, I believe only to a point - which I will now try to explain. Diesel engines are "compression ignition" engines. While I agree that there's nothing to burn until the injection of fuel, I still understand that under normal circumstances the "burn" is considered a "controlled" burn and progresses in a planned pattern. When the inlet temp gets too high, IIRC, the combustion occurs in a manner or pattern not intended by the designers and/or occurs over an overheated piston. Frankly, I don't know which it is - either can "kill" a piston. The difference may only depend on whether you are looking at it from a physical-macro or chemical-micro (i.e., molecular) level or perspective. When Bob Sheaves (member of the original design team for the DD Series 60 engine) was discussing intercooling and intake temps with Jim Shepherd (RV Safety Systems) at Busn'USA-2006 (or 07), he may have been "shortcutting" his terms - using "detonation" to explain another point to us mere mortals. I compliment you for noting (and posting) the difference. There's no excuse for a sloppy post, and I'm sorry if I introduced any confusion. Marc Bourget |
