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4 stroke t-maxx project
here's my work in progress its a t-maxx 2.5 what just didnt haver enough torque for my liking so i decided to drop a saito fa-40 in[>:] any suggestions, thoughts, doubts..i want to hear it
http://i289.photobucket.com/albums/l...t/DSCN1656.jpg http://i289.photobucket.com/albums/l...t/DSCN1655.jpg http://i289.photobucket.com/albums/l...t/DSCN1653.jpg http://i289.photobucket.com/albums/l...t/DSCN1650.jpg |
RE: 4 stroke t-maxx project
Holy S**T!
That thing is gonna go through like 5 spur gears a day! :O:O:O |
RE: 4 stroke t-maxx project
DANG! Let us know how it runs.
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RE: 4 stroke t-maxx project
ORIGINAL: willashcroft Holy S**T! That thing is gonna go through like 5 spur gears a day! :O:O:O |
RE: 4 stroke t-maxx project
Sweeeeeet.... I have a Saito 125 that needs a home... :) Let us know how it goes.. sweet running engines.. I think that you are going to lose some serious top end speed though as the saito only revs to about 10K..
Love to see some video when you get it up and running! |
RE: 4 stroke t-maxx project
All I can say is HOLY !!!!!!! that thing looks like a BIGTIME spur gear masher!!!! (unless u run a steel spur) That looks SWEET though man!!! keep us posted on the work in progress!!! [:-][X(]
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RE: 4 stroke t-maxx project
ORIGINAL: Geardaddys Sweeeeeet.... I have a Saito 125 that needs a home... :) Let us know how it goes.. sweet running engines.. I think that you are going to lose some serious top end speed though as the saito only revs to about 10K.. Love to see some video when you get it up and running! With the gearing in the picture (CB and spur) its going to have horrible top speed. I would also like to see a video.[8D] Also you need something to keep that 4-stroke cool. They'll run 320+ in just a min with no cooling (other than air from driving) |
RE: 4 stroke t-maxx project
JB u are definitely right on the horrible top end part; those BIG 4-strokes dont put out a lot of rpm's; and they aren't known for top speed either......
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RE: 4 stroke t-maxx project
How does "speed" tie in with RPM's? It all depends on the final gear ratio, if gonzo compensates with a very small spur, the ratio will come out just right and these engines have more than enough torque to pull the higher ratio. If geared properly, it is expected that the performance should be similar to a TRX 3.3, maybe with a bit more power. Plus, airplane engines are accustomed to running at WOT through 90% of their running time... Why are you guys saying this will eat spurs? Its going to have less power than a BB .28, and regular plastics can handle that power fine if set properly.
Gonzo, you have to dish out the details on the clutch man. I'm doing my own 4-stroke on road project with a Saito 56, please dish the info[8D]. It looks like you are running a regular car setup, I was told to look for heli clutches (which look friggin bizarre), the shaft size on these engines is bigger than the 2-strokes. Also, how did you attach the clutch bell at the end of the crank? Its completely threaded if I'm not mistaken. As JB stated, cooling will be a huge issue. Your best bet is if you could make a bracket to mount a fan propelled by the flywheel. Other than that, there are electric fans and water cooling, but I'm sure you are way ahead of me on this. Very nice build man, and the end result is very factory looking[sm=thumbup.gif], Tom. |
RE: 4 stroke t-maxx project
I realize that with enough tinkering and gearing, speed does not equal RPM's.. My point was that the stock motor turns about 35K at WOT, this engine will turn 12 max..I think that it would take some serious gearing to make up for the loss of 23,000 RPM's..
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RE: 4 stroke t-maxx project
Keep the gearing tall, or you're gonna float the valves[X(].You are using an engine designed to spin an 11 inch prop (high rotating mass) 12K RPM. You are using a flywheel (low rotating mass) 13K or more RPM. Use a small spur and a large pininon.
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RE: 4 stroke t-maxx project
rcnitrohead: speed has everything to with RPM. With a centrifugal clutch, at some point below max RPM(wot) the clutch will lock up, therefore the RPM of the engine becomes part of the gear ratio. A little math will tell how fast the engine must turn at a given speed. That said, there's some thumpers out there in Revos and Savvys. I agree that with gearing that works with a 2stroke mill will not work with a thumper, but a suitable spur/ CB combo can be found. Cooling is an issue, as is the wear and tear on a ringed-piston motor that was designed to run at a steady RPM with a given load,
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RE: 4 stroke t-maxx project
^ So wouldn't that apply to both 2 and 4 stroke engines? I pointed that out towards Matt: "those BIG 4-strokes dont put out a lot of rpm's; and they aren't known for top speed either......". Top speed depends on the final ratio, not the engine RPM unless its direct drive using no gears eh?
Tom. |
RE: 4 stroke t-maxx project
ORIGINAL: rcnitrohead ^ So wouldn't that apply to both 2 and 4 stroke engines? I pointed that out towards Matt: "those BIG 4-strokes dont put out a lot of rpm's; and they aren't known for top speed either......". Top speed depends on the final ratio, not the engine RPM unless its direct drive using no gears eh? Tom. |
RE: 4 stroke t-maxx project
ORIGINAL: rcnitrohead How does "speed" tie in with RPM's? It all depends on the final gear ratio, if gonzo compensates with a very small spur, the ratio will come out just right and these engines have more than enough torque to pull the higher ratio. If geared properly, it is expected that the performance should be similar to a TRX 3.3, maybe with a bit more power. Plus, airplane engines are accustomed to running at WOT through 90% of their running time... Why are you guys saying this will eat spurs? Its going to have less power than a BB .28, and regular plastics can handle that power fine if set properly. Gonzo, you have to dish out the details on the clutch man. I'm doing my own 4-stroke on road project with a Saito 56, please dish the info[8D]. It looks like you are running a regular car setup, I was told to look for heli clutches (which look friggin bizarre), the shaft size on these engines is bigger than the 2-strokes. Also, how did you attach the clutch bell at the end of the crank? Its completely threaded if I'm not mistaken. As JB stated, cooling will be a huge issue. It looks like you got the mount machined (btw looks like an amazing piece), you best bet is if you could make a bracket to mount a fan propelled by the flywheel. Other than that, there are electric fans and water cooling, but I'm sure you are way ahead of me on this. Very nice build man, and the end result is very factory looking[sm=thumbup.gif], Tom. as for cooling i got lots of pc fans lying around so its just a matter of mounting one up...and gear ratio im thinking of just getting a big ass clutch bell for time being intill i order some gears and what not ill post a video all said and done. o yeah and this is the video that inspired me:D http://video.google.com/videoplay?do...42726948941707 EDIT: one more thing is it possible to get a rev rev limiter of some sort for the thing? cause floating vavles is the last thing i want |
RE: 4 stroke t-maxx project
I haven't done enough research to check that, but can't the engine be de-tuned to kill off some higher RPM's? Yep, read about doing that but I've read that even using the lightest springs, the engagement speed could be too high. The smallest springs for nitro I believe are .9mm, hopefully that combo will work. When you have time, definitely post up some more info on what you did to the shaft[sm=thumbup.gif]. Is the engine broken in already? Hopefully you have a tachometer to set it up since they are nearly impossible to set unless you are a 4-stroke master[8D].
Tom. |
RE: 4 stroke t-maxx project
I too would definitely be interested in what u did to make it fit(shaft and all) and how it seems to be "fitting" for lack of better terms.....
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RE: 4 stroke t-maxx project
Well Matt, a custom mount will be necessary either way, these engines are a little longer than their 2 stroke counterparts, so now 4 stroke will be even close to a bolt on unless you get one of the discontinued OS 4 Stroke car engines.
Tom. |
RE: 4 stroke t-maxx project
alright here's a pic of the saft..would of posted it sooner but i had my wisdom teeth pulled yesterday (fun stuff)
http://i289.photobucket.com/albums/l...t/DSCN1673.jpg ok so now that i have little more time ill try to explain how i did it. what i did was opened the back crack case and used a drill to rotate the crack while i went at the front saft with a dremel grinding little bye little till i was able to slide the bell house it hasnt been broken in yet but ive looked a the instructions manual and have a good idea how its done think its best for me to buy a airplane engine mount + prop/tach |
RE: 4 stroke t-maxx project
How did you keep the crank round? I did something similar and I could never keep it round.
Also, did you mill the flywheel and clutch shoes yourself? |
RE: 4 stroke t-maxx project
the trick is to have the crank rotating (i used a cordless drill) while you grind it down
the flywheel is made bye rb racing and the shoes..? cant rember what brand, but the flywheel, clutch shoes, and clutch bell is all made for the t-maxx i was thinking in order to get the clutch to ingage @ a lower rpm i sould be able to drill a small hole on each clutch shoe a fill them with led or something |
RE: 4 stroke t-maxx project
^ Yes, make them as heavy as possible and find the thinnest springs you can. Thats a big gamble to take with grinding down the shaft like that, but it looks like you have a different crank then stock?. Yes, for break in you will most likely need to invest in a stand/prop/tach/ temp guage if you don't have one already. Or you could always bolt up some wood and make a stand;).
The flywheel looks like one of RB's supercharger ones maybe? Gonzo, the Saitos come with fully threaded cranks, is that the stock crank from the 40? Thanks for everything, Tom. |
RE: 4 stroke t-maxx project
its the same crank it came with and bang on with the rb supercharger...would be sweet if i could supercharge it seeing how i have one lying around. just think supercharged 4-stroke :D but im not going to get ahead of my self one thing at a time
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RE: 4 stroke t-maxx project
here's a few more pics. it will be a little while before i get some more progress but ill keep you guys up to date
with the lid on http://i289.photobucket.com/albums/l...t/DSCN1675.jpg with the fuel lines hooked up http://i289.photobucket.com/albums/l...t/DSCN1680.jpg inside a rb supercharger if any of you were wondering http://i289.photobucket.com/albums/l...t/DSCN1679.jpg |
RE: 4 stroke t-maxx project
How do you start it ?
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