Engine Options

[Privateer187]

Hello all. I'm new here, and I'm getting ready to start a diesel trike build, and I'm sure in the coming months I'm going to be asking a lot of questions.

After doing a little research, I've narrowed down my options , but I still don't know what I should do. I've pretty much decided it either needs to be a B&S 34HP diesel, or one of the older VW diesels. I'm hoping to get feedback from anyone who has built bikes around these platforms. Basically, I'm concerned the B&S won't offer the performance that I need (80 mph+). I know that the VW diesel will, but I'm concerned about what it will do my desired fuel economy, and the fact that I don't know what all would be involved in adapting such an engine to this kind of use?

I'm looking forward to hearing what the community has to say about this. Thanks in advance.

[Privateer187]

It dawned on me after I posted it that I probably should have given some better info. The trike is going to be rear-wheel drive, on a modified Honda CMX450 (or similar) frame with a CVT transmission. Probably a Comet Duster. Hope this helps.

[TedV]

have you seen the thread https://www.dieselbikeforum.com/view ... 28&start=0 ? 34hp should get you the speed, but the more aero drag you have the more it will kill your top speed and economy.

I've messed with a few VW motors. Both of my current diesels in cars are running a conservative 21 psi. You can get MUCH more than the 34hp, but you wont get the economy with a heavy throttle. My cars are in the 40-50 mpg US range.

[Privateer187]

The thread says that the 34HP should go about 100, best case scenario. That is acceptable, because I figure that with reasonably tall gearing my top end won't drop below my desired 80mph, and might even exceed that. I've searched, and I haven't found any fuel consumption figures for the B&S 34HP diesel motors. Can you direct me to a thread or website that would so that I can calculate estimated fuel economy?

P.S. Thankls for the help. I guess I really don't want to use a car engine for this application. The B&S sounds good, even if it is a little on the pricey side. Any cheaper options that perform about the same?

[Sphere]

Obviously, riding at 80mph adversely affects fuel economy. Also rev'ing the engine at the top end of its rpm range will hurt you. Still should be a good deal better than petrol though.

[Privateer187]

I know it. The only reason that I have to have that kind of speed is because of my location. I live in the boondocks, and the two roads that I have to travel every day of my life are a very poorly regulated state highway, where the typical speed is about 20 over the posted speed limit, and Interstate 40, where the sky seems to be the limit. I figure if I can at least go 80, I won't get run over.

But no, I have no illusions about posting top fuel economy at 80mph. One hopes that the fuel economy won't drop too far below my gasoline counter parts, though.

[LocomotiveBreath]

The thread says that the 34HP should go about 100, best case scenario. That is acceptable, because I figure that with reasonably tall gearing my top end won't drop below my desired 80mph, and might even exceed that. I've searched, and I haven't found any fuel consumption figures for the B&S 34HP diesel motors. Can you direct me to a thread or website that would so that I can calculate estimated fuel economy?

P.S. Thankls for the help. I guess I really don't want to use a car engine for this application. The B&S sounds good, even if it is a little on the pricey side. Any cheaper options that perform about the same?

Are you looking for this? One is the 31hp and the other for the 34hp Diahatsu Briggs 3LC, I don't know why Briggs & Stratton pulled these graphs, I have them saved in my files.

[TedV]

Are you looking for this? One is the 31hp and the other for the 34hp Diahatsu Briggs 3LC, I don't know why Briggs & Stratton pulled these graphs, I have them saved in my files.

Thanks, I know I was. I have the power graphs but not the fuel. Would you sat the DM950DTH is the current model DM954DT?? All the motors in this range seem to have about the same fuel consumption per KwHr.