my 4x4 two cylinder turbo'd cart build

[mudduck7.3]

i did manage to get some more work done on the cart today. got the rear axle narrowed down , the engine is in the cart but not yet mounted , the transfer case is about halfway mounted , the motor transfercase and driveline brake should be mounted by tomarrow and i will be starting into the onelink. ill have some more pics up tomarrow. i think ill also be making the vette body 6 or 8 inches wider to make more room for the shifter

 

[mudduck7.3]

Well, truly it works like this-

You could push a 78 Bronco with a weedeater, if you gear it low enough. You could track its speed with a calendar, but it would work...

None too practical, though. You would lose quite a bit of power to all that rotating mass. How much gear reduction is "serious"? Have you done the math? What are your projected numbers? How slow you wanna go?

I wouldn't call it a flame, I'd call it a real concern. Personally, and this IS my personal opinion, it's not worth the effort, as such. Take it for what it's worth, or blow us off. Just don't say you weren't warned...

On second thought, prove us wrong- that'd be cool, too...

i haven't done the math on it (even though i should have already), i was actually more concerned about it being too low geared but i can always change sprocket ratios on the engine and trans . im really not trying to go fast by any means , all i need is enough speed in high gear to play on the trails (maybe 25-30 mph would be plenty). i would really like to have more of a crawler ratio than top speed as it will be on hills and in the mud and rocks more than pavement .

really the only reason im running such a big tire is because of the axles being so overkill for the cart , theres not much ground clearance if i were to run a 26 " tire or somethin small like that

 

[Bluethunder3320]

Well i think its cool that you are still gonna try, i mean, if you didnt, we'd never know if it would work or not.

Do you have an idea when it will be driveable?

Also are you running a governor on the turbo 18hp?

 

[HellSpawn]

Well i think its cool that you are still gonna try, i mean, if you didnt, we'd never know if it would work or not.

Do you have an idea when it will be driveable?

Also are you running a governor on the turbo 18hp?

I wouldn't call that a turbo 18hp, Hes going to need a lot smaller turbo before he even can dream about making it into boost.

 

[Doc Sprocket]

You do need to sit down with a calculator. 25MPH just isn't going to happen. I'm not trying to bash you around, believe me. I just don't think it's feasible with that driveline combo.

 

[bighead]

How much do you think the kart will weigh? You said 500lbs?

Can you post a pic of the original go kart frame you said you were using. Wondering how your going to hang them axle to a kart frame?

Interesting thread for sure. Hmmm

 

[Doc Sprocket]

How are you going to steer that pig, anyway?

 

[Cam]

i think hes aiming for the old sustained loss of traction steering mechanism

 

[The Mechtician]

i think hes aiming for the old sustained loss of traction steering mechanism

LMFAO thanx for the laugh, Cam! I might make this my new sig line...

I agree with HellSpawn, the turbo on that engine is just extra weight, I'd be surprised if it made any boost at all and in fact the engine probably makes less than 18 horses with that huge restriction in the exhaust and intake plumbing. A turbo from a smart car (a la lemegacool) would work a lot better. Bigger isn't necessarily better when it comes to turbos and superchargers!

Also, the axles alone probably weigh 500 pounds, there's no way the whole kart is gonna weigh anything less than 1300 pounds by the time it's all said and done.

I'm not trying to $hit on mudduck's project. I built some crazy stuff when I was young, and not all of it worked as good as I thought it would. That's how you learn though, y'know? If I had the internet back then, with a forum like this full of knowledgeable and helpful people, my high school rototiller kart probably would have gone faster than walking speed Don't stop your build mudduck, I wanna see it running just as much as you do, but you may be disappointed with the results if you continue on your current path...

 

[fowler]

the first set of pics shows u how hes doing it

the front axil steers

 

[Bugzuki]

Looks like a fun project. I was thinking the same about weight and speed. But my main thought was you should have started with Samurai axels instead.

If you are going to take this on trails, how are you going to setup the suspension to get any flex on something so light? Have you thought about a rollcage for when that goes over backwards on a hill?

Good luck and hope it works.

 

[mudduck7.3]

well ive only been working on it for 3 days now and ive made some decent progress , i would hope to have it drivable within a few weeks or so maybe sooner. i am planning to take the governor off.

i know the turbo is a little too big for the motor it was just a spare for one of my diesel trucks so its pretty much a freebie, we haven't hooked a boost guage on it yet but it is spooling a lot more than i expected it to so i guess we will have to see what happens. the engine seems to be a little snappier with the turbo but that could just be in my head too.

i have a couple options for the steering , i have a power steering box i could use without running a pump to it which would give me 4 turns crank to crank , which might be enough to turn it without runnin . or i have the parts to make it full hydro steering IF i have to.

as for the axles , they are nowhere near 500 lbs by themselves. after being debraked and narrowed i can pick up and carry each complete axle across the shop with out much trouble and im only 145 lbs and im not very built.i think for now im going to run the front shocks off of a dirt bike on all four corners and see how they do , i know they won't be too stiff but im worried they might be too soft . if i need to i can put two on each wheel. i am gonna cage it but that will be closer the end of the build after the body gets widened .

keep in mind that so far in this build i have 260$ into it . the reason i used the axles , turbo ,body ,tires is because they were parts that were layin at my shop that would never get used otherwise. i know sammy axles and a smaller turbo would have been better and lighter but all the parts i have in it are either free or next to free , its just a budget build and if something ends up not working out i can always replace it with something that will.

i will have some pics of the progress up tonight.

 

[T.E.D. Jordan]

I made the mistake of thinking it was a '2 stroke' to start with then quickly realised it was a '2 cylinder' which is why I didnt post my reasons for what I said, but my comments were based on the things you haven't factored in. As mentioned on here, that turbo is MASSIVE for such a small engine, The only reason you've heard it spooling is because its under no load at all. Give it load and IF its a high revving engine you'll not only be INCREDIBLY lucky if it boosts, but if that does happen you'll be incredibly lucky if something doesnt let go and make its way through the head/side of the engine towards the driver what with the massive amount of friction your low gearing and choice of running gear will create. Worst case scenario is it could let go of the flywheel at high rpm, best case scenerio is that it just 'pops'. Some engines with stock internals can handle alot more power without internal upgrades, smaller engines not so much bar some of the european small cars.

You've also mentioned that it spools up nicely when revved, again because theres no load, but where are you pumping oil from? I maybe cant see your oil line from engine to turbo but you'll rapidly waste the turbo without it. It also needs jetted to push oil at correct pressure, then gravity fed back to the sump. There also needs to be an oil cooler with a low temp thermostat as it looks to be an cooled engine.

You also mention head work and skimming it to heighten the compression. On a boosted engine you to need to massively lower the compression! Headwork would include (on this engine) boring the head out as much as is safe and maybe use of a decompression plate between head and block to get alot lower compression

Geezzz I could tell you where you're going wrong on this kart all day but from the genuine helpful comments posted so far and the response you've given to them, I shoulf just sit back and hope to be dramatically proven wrong.

Jordan

 

[Cam]

LMFAO thanx for the laugh, Cam! I might make this my new sig line...

haha, your welcome mate

let go of the flywheel at high rpm

flywheel fly off?

 

[T.E.D. Jordan]

Yep. youtube will show you what can happen when flywheels let go of the crankshaft. Its a common term.

Jordan

 

[Doc Sprocket]

the first set of pics shows u how hes doing it

the front axil steers

I ***MEANT***-

By what means will you transmit the force from the steering wheel to turn those big, heavy front tires!!!

Fortunately, Mudduck knew what I meant. Anyways, If you can find a manual box or better yet a rack and pinion, that's probably the best bet. Those rubber boulders aren't going to want to steer too easily, and probably not at all if you were to attempt a direct steer like most karts.

I don't suggest hydro- Not only will it add a bunch more weight and complexity, you certainly cannot afford to lose any horsepower to a hydraulic pump...

 

[DustinWolfe]

The only reason you've heard it spooling is because its under no load at all. Give it load and IF its a high revving engine you'll not only be INCREDIBLY lucky if it boosts

? no load produces more boost now? when did that change? i feel like you need to reevaluate this entire paragraph. your correct about the oiling but not about basically everyhting else

 

[mudduck7.3]

as far as the motor goes , if it goes it goes , if it blows .... bigger engine time. im puttin a 1/4 inch plate behind the seat just incase the head were to try to blow off.and when it comes to boostin a high compression engine i know a little about it . my 7.3 idi in my daily driver has 22:1 compression and i boost 20 psi all day long with it on the stock headbolts so im pretty confident this motor will be fine with the MAYBE 5 lbs at best .

i might just look into usin a manual steering box from an old pick up or somethin for the steering

 

[mudduck7.3]

heres some pics of what i got done today:
got the motor dropped in , really snug but ill make some more room for it . i still need to make the mounting plate for it

got to work mounting the trans/transfer case. this took a lot of cutting/bending/grinding/welding/test fitting, but finally got it where i liked it and still have manageable driveline angles

i also changed my mind on the one link suspension idea, theres just not enough room to try to make it work . so im going to go with a two link/radius arm style suspension. i started into the front but still have to make the lower links that go to the bottom of the axle , but by tomarrow the front should be sitting on the shocks on its own so i can take the support bars out and see how the dirtbike shocks will do

 

[B man]

cool