I realize that, but I am not a racer. Isn't geting the most out of your engie part of having a good setup? I just like to know what my engines are cabale of. But if you are a racer wouldn't you like to be able to match the load your buggy or truggy put on an engine then be able to try different setup to see how your engines respond? with a setup like this I will be able to test different pipes and fuels ect. to see what give the engine its best performance. I'm not a racer but if I was this would be a great tool to help me with my setup.

Right now I know how many rpm's my engines turn in a my MBX5T with stock gearing(Werks B6 does 38250 RPM) for example.once I get it all set up I will be able to get a prop to match those RPM numbers and then i can use that same setuo on different engnes and see how they compare. then I can use a larger prop to put evn more load to estimate which of the engines has more torque.

As far as fuel that is part of the reason for doing this. I mix my own and I can play with different mixtures to see which one perform the best.

Check it:

http://www.hudy.net/xhudy/products/p...89&kategoria=0

Check this one too:

http://www.rcplanet.com/RD_Logics_En...p/rdl15000.htm

I have seen those. I think I am going to build my own. here are a cople pics of what I am planning to build. Everything is just setting there, nothing is bolted down yet. I am still missing a few small peices but I already have most of what I will need already. The nice thing about a setup like this is that I will be able to use a bump box to start the engine and the prop won't have tp spin at the same speed as the engine. What do you all think?

Seems like alot of work for nothing. I can`t see how this is going to help you to choose a spesific engine for a spesific car or track, but as long as its just for fun..........

It would be quicker and easier to bolt in a few different engines in the car and actually drive them to compare them, that`s what I do

Hi!
Agree!

Hi jaka
            I need some piston/liners for m.v,vs 15 diesel can you help,thanks

Private messaging exists so threads don't need to be hijacked for stuff like this. Just FYI.

JUST ASKED A QUESTION  ARE YOU FOR REAL  GET A LIFE

I don't get it.  Changing carbs, adding flywheels, changing heads?  How does this provide any comparison between engines?  Why not just get an older car/truck/buggy, put your test engines in it and run the heck out of them?

Your post has nothing to do with the subject of the thread, sorry if I ticked you off.

I personally would want to simply break the engine in, only because I don't think a car engine gets to its peak during break in and it should, IMO.

I can see the reasoning behind what the OP wants to accomplish. It's no different than testing a certain prop on more than one engine to suit a specific aircraft.

I do that too! But with this I can put the exact same load on different engines so comparison testing can be consistant. In a car/truck it wold be very difficult to reproduce the exact same amount of load from one engine to the next. so this would provide consistancy. Also I am will be able to compare the performance of one engine running different fuel, different pipes ect. or I could compare multiple engine running the same fuel or the same pipe to see how each of them perform. But this would provide consistancy for my tests.

If I could figure out a way to calculate actual real world power that would be awesome. All of the engine companies just put whatever performance number they want to on an engine. You never can really KNOW how much horse power or RPMs an engine is capable of by reading their marketing material. There is no standard by which they adhere to which makes comparing manufactures specs usless.

But testing a prop on various engines doesn't mean tearing the engines apart and changing heads and carbs. Break-in simply means running at less than full-out to start. It used to be that you would break-in a full size car with break-in oil and keeping under certain speeds for 500 miles or so.

Yakfish, how can you seriously say that you are comparing different engines when you change out two of the most critcal parts of the engine?

I am not a car person - thus my questions. But when I want to test out various airplane engines I put them on one plane and fly them. Same for breaking in - i use a trainer. I don't see how it is much different for car engines.

Well I like to bench run a engine for a little while to dial in the carb some. It can be a lot easier that way, than trying to do it in a car at first.
But I have run them in cars too, so it could go either way. Years ago when i was a lot more interested in cars we used to have to run them in the cars as at the time we couldn't put a prop on them. But sometimes it was a pain getting a cantankerous  engine to run and dial it in too.

I can promise you that unless you use a very small prop, getting over 28,000 rpm will be almost impossible with a prop. I am more interested in this as I think it would be awesome to convert a small car engine to fly a plane. Using a prop to break in your engines does have a lot of merit though and it seems you could get the needles set very easily if you could match the load experienced in your car.

Bact to the original post, that Master Airscrew prop at typical buggy-engine rpm`s is sure to explode and hurt/kill someone. Get one of those break-in rigs myself and others have linked to and be done with it, those fans can take the rpm`s unlike the typical plane prop you intend to use

A prop throwing a blade at very high rpm`s is no joke!

I know it's been previously stated but I'll reinforce the thought - Using an R/C airplane prop is not a good idea. I suspect that very few props can handle the forces from being spun at such high speeds. I'd check with the prop manufacturer for their speed recommendations before trying anything. You risk damaging the engine, the prop, YOURSELF and anyone/anything else in range of getting hit by shrapnel when your set-up goes KABOOM...

I don't have to worry about a prop doing 40,000 rpm. do the math. I am using a clutch, clutchbell and a spur gear. the spur gear is 43t and the clutch bell wil be 18t. that means the prop will be doing 16744 RPM when the engine is doing 40,000. I will be using a prop that will match the load of my MBX5T truggy. at WOT the engine in the truggy has been doing 39,000.

Guys we gave advice and he doesnt want to take our advice.

i think that if you can measure your rpm in the buggy then you have a good set up already. see what rpm you get at the end of the straight of just before a jump amd then try another engine to see if it reaches that same rpm or better.

also if your engine already is hitting 39,000 i think you need to regear some to better use the power of the engine. i would think most of these car engines ,ake thier best power in the 20,000-28,000 rpm range.

Good luck!

Most car engines are ported for that rpm. Most of the car engines I own currently have at least 175° of exhaust duration and average 17-19° blowdown timing. The highest timed engine I have runs 186° Exhaust and 19° blowdown. The crank timing varies significantly, but thats no different than airplane engines. I haven't seen any patterns with crank timing as I have with exhaust and blowdown. I have a tach sensor for my Spektrum DX3S radio, but most of the car guys that have this radio have said the Tach isnt accurate anyway so I havent bothered trying it on any of my cars.

As far as the prop choice on a car engine, I would think a Ducted fan prop is going to be the right prop to handle 30k+. Even carbon fibre props which was brought up before may not be robust enough. I would think a 6x4 or 5x6 would be small enough to let the engine turn up but load them enough to keep the conrod from going AWOL.

I like the break-in stand idea better - looks safer and easier at the cost of roughly $140..

I think if you check with Fromeco, the TNC tach they offer will work for your testing.

-Sean

I envy that tach. Someday, I will own one. Unfortunately, today isnt that day and tomorrow doesnt look good either.. They do have a nice tach though.