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    Marietta, GA
  • Interests
    Tuning of Supercharged Alcohol Professional Drag Racing Cars

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  1. Not sure I agree with that earlier statement that altitude does not reduce power on a turbo charged diesel engine. If somebody has driven up over 5000ft then you wouldn't say that. I have a Detroit Series 60 and when climbing up over 5000 ft there is a definite reduction of power and up over 7000 ft it is even more noticable. My turbo is showing 42 lbs of boost the whole time and I keep it at the peak horsepower RPM when climbing and the higher I get the less power I have. There is only so much that turbo can do to compensate for the thin air.
  2. I just bought heavy duty 28" blades Trico Part Number 67-281 from Amazon. One point I should bring up is that you cannot get just replacement blades for any wiper over 28". My mh calls for 32" blades which are way longer then what I need so I dropped back to a 28" blade and they are a lot cheaper plus you can get replacement blades for $17. The other thing is to enclose your whole wiper in one of the swim noodles you can get at Walmart or other toy stores to keep the sun and ozone off them when the mh is not being used. Go here and look up your correct blade for your RV the google it or check Amazon directly http://www.tricoproducts.com/Trade/OnlineCatalog If you want a description of each model HD blade then go here http://www.tricoproducts.com/Trade/WiperProducts/MoreProducts/HeavyDuty
  3. I have adjusted the valve lash on several Cummins motors and no problem. I could probably do it on my Detroit but they also want to set the injector height not sure if I want to mess with that. My injectors run off a camshaft like a valve. Detroit wants this done at 60K miles and they will not do it any sooner regardless of time because they say it has to be fully broken in. I did find YouTube videos on how to do it and you might want to search for a video on doing yours.
  4. •That link I included above gives the Sweet Spot for most big motors but one has to be very careful because they make numerous versions of the same engine with different power ratings and Sweet spots. You are 100% correct in that one's MH may not be able to be driven at the Sweet Spot because of other influences. I believe that most mh owners drive at the point their mh's just shift into 6th gear. Mine will shift in at 58 mph and will stay there if I am in the Economy mode and 62 mph just happens to match my Sweet Spot RPM so that is where I drive. The biggest contibuting factor to MPG is the drag coeificient of the MH and the second biggest factor is the person behind the wheel. So yes again the Sweet Spot may not be the most efficient point in which you can drive because of these other factors. If the MH designer that decided on the overall gearing and engine RPM did not take into account the Sweet Spot then that presents a problem. I also find that smaller engines run at higher RPMs to make power which also make it hard to have the Sweet Spot at the average 60-62 mph point. Brake Specific Fuel Consumption (or BSFC) is the ratio between the engine's fuel mass consumption and the crankshaft power it is producing. So yes, the motors Sweet Spot is the point where the BSFC is the lowest which is the point in which you make the most HP with the lowest Gallons Per Hour fuel flow. A lot of people confuse Sweet Spot of the engine with the Comfort Zone at which speed they feel good driving the MH at.
  5. Brett, I don't want to get too technical here and bore people BUT the BSFC can only be computed on a engine dyno (We do this all the time with our big racing motors) and the best BSFC or the lowest fuel consumption versus the best HP can only be computed on a dyno which is the named the Sweet Spot. This best BSFC POINT (Sweet Spot) does not change depending on the weight of the vehicle. The amount of fuel used to maintain the speed based on weight at that lowest BSFC point may change but not the RPM of the best BSFC point. In other words if on my Detroit Series 60 the best BSFC vs HP is at 1450 rpm for a 80,000 lb truck it still remains at 1450 rpm with my 45,000 lb motorhome BUT the amount of fuel used at the best BSFC point is higher for the 80K lb truck than it is for the 45K motorhome.
  6. Got hold of my mechanical engineering friend at the diesel manufacture and this is what he gave me. "Engine's sweet spot is the RPM where the brake specific fuel consumption (BSFC) is at a minimum" It is a real term. Based on that definition I did a further search on the internet and found this which puts it more in laymans terms. The Sweet Spot __________________ This article gives the engineered Sweet Spot for a lot of motors. The motor doesn't know what chassis it is sitting in so a DD S-60 is a DD S-60 in a mh or a truck. http://www.truckinginfo.com/hdt/archives/2007/06/068a0706.asp
  7. You cannot just go out and time today's motor by your ear like we used to years ago because they have a sensor that detects ping or what is called valve knock and automatically retards the motor to stop it. Used to be years ago you could advance the ignition timing until you got three pings out of the motor under acceleration in 3rd gear at 20 mph. It worked great and put the motor at the optimum point. With today's motors you will never hear the ping because the accelerometer screwed into the motor has better hearing than you and will retard it before you hear it. So what happens is you keep advancing the ignition until you get to a point that the computer gives up then you will damage the motor. This secret wire I believe is the wire that runs to this accelerometer on the side of the engine block usually located down by the oil pan about midway back on the passenger side. Take that plug off and now you should be able to time it by ear. Take that wire off that sensor then find a hill and if an automatic tranny accelarate lightly up the hill in third gear and listen for the valve knock. The engine needs to be at operating temps. If no knock then turn the distributor in the opposite direction of the rotation of the rotor just a small amount and try it again until you get spome valve clatter or pinging then back off on the distributor just a little until it goes away.
  8. My handle has a LED in it and I went to Radio Shack and bought another one and soldered it in and it works great.
  9. I drive all over California all the time and have never been pulled over and my MH is 44' and has a Wrangler following it. Just came back from Carmel. I do observe the 55 MPH limit at 60 MPH on my GPS because my speedometer is a couple mph off. You can't drive much faster than 60 mph on I-5 because the road surface is so bad especially the expansion joints either side of a overpass or bridge. One question I would have to ask on the combined length of the MH and toad is if that is bumper to bumper or front mirrors to back of spare tire (Wrangler). I guess I should measure both and see if it makes a difference. I wonder how much leeway they will give you if you are a little over. There are a lot of States that have that total 65' length restriction but not many that enforce it.
  10. MikeCanter

    Tire Blowout Today

    Check out this link about Zipper Flats. You would swear that the picture of your tire was used in the document. http://www.rma.org/getfile.cfm?ID=953&type=publication
  11. Hi Danny. The reason the shock looks short on that side is that the motohome is leaning so the shock is contracted. Is this a leaf spring or an air bag suspension? If it is a air bag suspension then will it level out when the motor is started and air pressure builds up in the tanks? If it is a leaf spring suspension then there is a good possibility of a broken spring or another suspension problem.
  12. Make sure that you have the correct Filter Minder installed for your make diesel motor. Cummins requires a 25" reminder and a CAT requires a 30" reminder. Consult your engine manufacturer for definite figures. My Detroit requires a 20" Minder. See here http://www.donaldson.com/en/engine/support/datalibrary/053979.pdf
  13. Like I said I have had pyrometers on a diesel and I tune several professional racecars as a paying hobby. I use eight EGTs on each engine and use them to tell me what is going on with the motor. I do know pyrometers and EGTs reading very well. If those were the readings I was getting on my diesel I would be happy. Let me know if you have any questions about it. I will be more than glad to answer them. You might find this to be interesting reading. http://www.bankspower.com/techarticles/show/25-why-egt-is-important
  14. I had an EGT sensor on my last MH with a Cummins motor and a Banks Power Pack kit. When installing the Banks kit one adjusted the fuel so you had a max EGT of 1300* at wide open throttle under load going up a steep grade. This is the max power EGT. The EGTs on a diesel are very different to those on a gasoline motor. On a gas motor the leaner the mixture the higher the EGTs. Not so on a diesel, it is totally opposite, the more fuel the higher the EGT. It has nothing to do with boost but the higher the EGT the more the turbo will spin up so more boost and power. According to Banks the straight and level normal cruise will be in the 700 to 1000* range and wide open full more should not exceed 1300*. If it does then you need to either downshift or let up some on the throttle. I would say your motor is 100% normal. Does your pyrometer redline at 1300*? I would expect it is because mine was.
  15. Buying a good Sears Craftsman sparkplug 5/8 socket with foam inside to hold the plug firmly is a good start. Next you want to obtain a packet of anti-seize compound to put lightly on the plug threads so they will be easy to take out next time and lubricate the threads when you put the plug in. The major damage to threads in the cylinder hole is caused by using a ratchet on the plug socket to start the plug in the hole. If you hold the extension to the plug socket in your fingers and hold it straight and turn it slowly by hand until the threads start you will not cross thread it. If it gets tight right away then it is crossthreading so stop and unscrew it by hand and start again. Like I said if they get tight right away then stop. It is only if you use a ratchet and they get tight and you keep going that you will damage the threads. Also the anti-sieze compound on the threads acts as a lubricant to help them go in. On our race car we change plugs twice for each race. Once for the warmup and then for the race. We do this 6-8 times a day and never damage a head. We always start them by hand. My recomendation is to get double platnium Autolite plugs as the replacement and they will go on for another 60,000 plus miles. If you run into a problem when doing it then stop and let us know and we can help you.
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