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Old 08-14-2010, 10:21 AM   #11
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Re: Crossed the Bridge

The sluggishness should correspond to the engine RPM, not to the gear in use. Diesels have a much narrower "power band" in terms of RPM. My uneducated guess is that you are staying in the lower gears too long instead of up-shifting. Winding the engine up to the redline before shifting may be great for imported sports cars and sedans, but not so much for a diesel engine.

Ever hear a heavily-loaded tractor-trailer take off from a stop light, up-shifting about once every 3 seconds, one second in each gear and two seconds to shift?

I can't find a power curve graph for the Brazilian engine, but for reference I checked the Detroit Diesel web page on a link from Freightliner. The engine that came up had 1550 ft-lbs of torque at 1100 rpm, but less than 900 at 2100 and falling fast. The horsepower rating on that engine is 455 at 1800 RPM, but the curve drops like a rock from that point upward, with less than 325 hp at 2100 RPM. If I extrapolate off the end of the chart (which ends at 2100 RPM), it looks like the HP is down to around 250 at 2200. Your turbo should extend the upper RPM power range a bit and mitigate some of the power fall-off, but that still doesn't make it a sports car.

Maybe someone like Elliot or neverenufhp with thousands instead of dozens of diesel miles behind them can chime in, but in my book the engine itself will either be sluggish in all gears or in none of them. You have to match the road speed with the right gear for good power.
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Old 08-14-2010, 11:58 AM   #12
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Re: Crossed the Bridge

Thanks Redbear/Bus-bro. The power curve graph you mentioned, RB, is interesting. I think that I need to get some miles and develop my driving style, for sure. I suppose I need a tutorial of sorts for driving it. I can only apply my knowledge of driving gas engines, which isn't exactly enough to carry me over to figuring out the diesel. I was pushing up the rpms just like I would in a gas powered engine, but think I need to try getting through the gears quicker. Nonetheless, a mech. said that the turbo should kick in in all the gears, which it's not. When I first got her, she'd been down for 2 months without being driven. When I fired her up, there was minimal smoke (black), and when I got her out on the highway, there was more black smoke, but it cleared up soon. I was going for "blowing out the cobwebs" for a good hundred miles, then stopped and gave her a full service of oil change, all filters, coolant check, transmission check, lube, and a truck wash. The smoke disappeared and hasn't been seen again since that service. All in all, I'm very pleased. I guess the notion of the turbo going had me scared- and it is worrisome. I hate being at the mercy of a mech., and being clueless myself.

I cleaned off the rear end and found the spec plate- my gear ratio is 4.30 and 6.00. I can certainly live with that.

Also, does anyone know what this is for?

I was kind of hoping it was a door lock of sorts, but I can't figure out how to use it. It's kind of wobbly and doesn't want to move much either direction. Any ideas? Thanks everyone. Viva la Skoolies.
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Old 08-14-2010, 09:03 PM   #13
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Re: Crossed the Bridge

Regarding the door lock, I figured it out, and it's just that- a lock of sorts. I can't get it to lock yet, though. I'll probably end up doing something else for a lock, anyway, since this type uses the door opening mechanism, which I want to remove to free up space in the driver's area and dash. Oh well, it's kind of a neat idea- never seen one like it before.
Got the road crud cleaned from the undercarriage, locks installed on the battery box and fuel door, and 4 seats removed- all in 100 deg. temps. FUN.
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Old 08-14-2010, 09:56 PM   #14
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Re: Crossed the Bridge


When a turbo charger goes bad, there are usually fiery bits of metal flying out the exhaust pipe and other good clues. Your engine is not a particularly powerful one -- keep the revs down and let it do what it likes to do (which is to trundle along).

Hey.... I'm offended! It does NOT take me two seconds to change gears! (Talking about 18-wheelers now.)

"Thousands" of diesel miles? How about millions? When people ride with me in a car, they tell me I drive like an old fogey. Even when I drive a Corvette. That's just how I'm used to driving. Your bus is NOT a sports car, so it may seem a bit sluggish to you at first. That's how it's supposed to be. It is a Big Heavy Thing.
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Old 08-14-2010, 10:16 PM   #15
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Re: Crossed the Bridge

O.K.- I admit that I don't know much at all about the proper function of the turbo, and it was suggested that the turbo was acting up after I described the 'symptoms'- the sluggishness getting to speed in the low gears. Should I feel the turbo kick in in all the gears? I feel it noticeably in 4th and 5th, and not so much so in 3rd, but not at all in 1st and 2nd. Is this normal operation? If it is, I can live with it, and I'm even fine cruising at a easy 55 in 5th- I'm used to it. I just want to know my rig is running as it should, and I don't have the experience yet to know.
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Old 08-14-2010, 10:38 PM   #16
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Re: Crossed the Bridge


Since it is normal to go thru the lower gears faster than the higher ones, I'm guessing you just don't have time to register when "the boost comes on", or "the turbo spools up" in the lower gears. If it pulls OK in top gear, there is nothing wrong with the turbo. It does not know what gear you are in.
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Old 08-14-2010, 10:54 PM   #17
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Re: Crossed the Bridge

Thanks Elliot- that's reassuring. You saying that not only makes me feel better, but re-instills my general mistrust for a lot of mechanics. There are good ones, but it seems there are more that would take advantage of someone's ignorance. I explained the situation to a local diesel mechanic exactly as I did in my previous post, to be told that it "sounds like my turbo's acting up" and should be checked out (to the tune of $65/hr.). I can only assume that either he's dishonest or ignorant, and neither should be tolerated from a "professional". Thanks again.
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Old 08-14-2010, 11:09 PM   #18
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Re: Crossed the Bridge

Well.... There could be some minor issue with the waste gate or something. The hose to the waste gate might be leaking. (The waste gate is a kind'a safety valve that limits the turbo pressure to a safe level.) But the turbo charger itself either works or explodes -- generally speaking from my experience with 18-wheelers.

"Acting up"... is something computer programs do.
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Old 08-14-2010, 11:16 PM   #19
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Re: Crossed the Bridge

I don't see anything here to suggest a turbo issue. If you were having a problem with your turbo not building enough boost, I think you would be seeing a lot of black smoke, but you're saying the black has cleared up, so I think you're fine. Like Elliot said, turbos take a bit to spool up. So in the lower gears, they don't build as much pressure because when you let off, the exhaust flow slows. This is one area where an auto really shines. My allison allows the engine to pretty much pull nonstop, there is almost no hesitation when it shifts.

There is one other thing, though...turbos don't seem to build as much boost if there isn't much of a load on the engine. In the lower gears, the engine doesn't see much of a load, because of the gearing. In the higher gears the engine is able to "load up" more, and the turbo then builds more pressure. This has been my observations at least. Installing a boost gauge and pyro is very helpful, and somewhat educational.

If you want to get a little more from your engine, though, here is an incredibly helpful website from nevrenufhp...http://www.freewebs.com/nevrenufhp/index.htm
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Old 08-14-2010, 11:19 PM   #20
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Re: Crossed the Bridge

Before you start worrying about the waste gate...check to see if you even have one. Take a pic of the turbo and we'll be able to tell you. I am actually doubting you have one
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