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Daves Other V-twin +Turbo (Drift Quad)


Muncie

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7 minutes ago, Kimjon said:

Looks like a harley with that amount of offset.

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Does a bit doesn't it? Where it is puts motor mount in center of chassis with the weight of the turbo etc it all feels pretty balanced. Still got to fit a belt drive in there, going to run a 1-1 timing belt to a jackshaft and a normal centrifugal clutch off that. Prefer the idea of getting whipped with a belt then gnawed at by a chain when something inevitably breaks.

My other twin seems to lengthen chain then throw them, im sure this will do it as well hopefully a belt will smooth it out a bit.

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@KimjonIm not sure if a cvt is neccessary or would actually live on this size engine they are heinously expensive!

I was looking for one to fit the 1 1/8" inch shaft just the driver was nz$650 and had to come from states. A snow mobile type is more affordable and can take the power but are physically Hoooouge and need (driven side is like 10 inch) modifying to run on a lower revving non 2 stroke.

For that cost i can fit 2x 18hp rated clutches and hopefully load engine up and build boost once it spools up its gonna be a party for sure!

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It had to happen. Turbo time!!!

This kid makes amazing stuff given his age. I've been following his builds for a few years now and I've always been impressed by his problem solving skills with limited tools. He's now getting better stuff, and the build quality reflects this.

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  • 4 weeks later...

Decided to have a play with the turbo back to the inlet manifold of engine. It occurred to me how much extra work it will be to have it blow through.

So dummied it all up draw through and stood back..... makes everything so much easier think I'll just do it.

Just going to do 2x 90 degree bends off inlet manifold as its 2 barrel and straight in to the 2" tube.

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Unbolted all the factory Honda governor and throttle gear today ive already gutted the governor out but left the arm on the block as was a pig to get out and would leave a hole for oil to leak from.

Anyway shoved engine forward because i could and realized the seat position is mint!

Will need guards around exhaust but to be fair heatwrap and a simple tube cover will be enough to stop your leg getting burned.

Chain or belt drive will need guarding too but i could comfortably ride this.

 

 

 

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Something i have in my head that wont affect getting it running but will be a pain in the ass is the electronic rev limiter that kicks in at 3800-4000 rpm, thats right in the fun zone!

If anyone is a small engine guru and knows how to disable it let me know? It should do 5000rpm with no issues with the turbo and big carby probably more so i want to sort it.

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Rumour has it the rev limit is built in to the coils wonder if some coil on plug arrangement can be done...

Apparently gx390 coils are the same but do not have the rev limit functionality, they annoyingly are quite pricey too from NR Racing.

 

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Finally got around to doing an oil drain from turbo back in to sump today its just into an existing oil drain as there is 2 on these motors, will see if theres enough flow but so far turbos not smoking and spins for about 30 seconds after engine stops.

Ive also rigged up an oil pressure gauge as before i knew there was some pressure but not if it dropped off with revs feeding turbo. It maintains about 45-50 psi so bang on.

Ran it for about 30 minutes today to see if anything leaked oil and to really get the turbo nice and heat soaked. It can move plenty of air thats for sure! Especially banging the limiter.

Now to save coin buy parts and get it done about $600 would have it moving under its own power.

 

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Done some research and can get dual V belt drive pulleys 1 for engine and 1 for a jackshaft for about $40 did think about cog belts but alignment and lifespan might suck.... 

This thing is getting built with rulers string and an eyecrometer although yuck i think it'll be a good stop gap to just get it working.

Will then run a 3/4 jackshaft so i can fit normal go kart centrifugal clutches probably 2 of them 2 sprockets and chains should be bullet proof enough. My other v twin hasn't killed a clutch yet doesn't slip despite been fed 25+hp and ive given it an utter pasting for 2 years and only been rated  to 11hp, it does kill chains though.

This should work ok and belts will stop the v twin from hammering the chain. Talk me out of it??

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Ive also quit working on spacecraft recently and now work for a tool company so should be able to get my hands on all the tools i need to up my game shortly.

Last employer might explain why ive gone so overkill on my scooter and this thing...... ive seen some things! Inspiring.

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Did some more mucking around with this today found engine to be struggling against the closed position of the VGT on the turbo, small tweak to the stop and its way happier it was affecting it at idle and choking it when revved.  and it actually spools up properly now with no load it spools and blasts copious amounts of air at about 3200-3500 rpm then hits the 3800rpm limiter.

Hoping with load that'll come on earlier and a actuator will keep it there by variation of the vanes angle.

The actuator on the turbo runs on a vaccum signal not pressure so hopefully i just need to swap that out with a conventional pressurised wastegate actuator.

Ignition wise theres a few things i can do to ditch the rev limiter,

1. switch to the single cylinder coils to maintain CDI (Expensive)

2. switch to the earlier non CDI v-twin coils like on my other engine

3. Build something custom, probably best option as I'll need different timing to a naturally aspirated engine to get the best out of it.

Could maybe build a speeduino or megasquirt and just run ignition only and have option for EFI at a later date. 

 

 

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Built an SU carb today. 

This is the one that i put through the ultrasonic cleaner at work its looking pretty mint now.

@sr2 was kind enough to donate the the float chamber i was missing, that got a refurb and assembled and fitted to carb. Also happens to have a 4mm pushlock for a boost reference.

Boom complete carb!

 

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The origins of these carbs are from a Triumph 2.5tc the later shape that got a longer manifold.

Could never get them to run right they would be fine puttering round but wind the car out you would just hit the wall engine would loose power.

20 years later figured out why! Tiny piece of swarf was rattling around in between the ferrules of the line that connects the jet to the float bowl. 

 

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Great thing now is im back to using a blowthrough configuration. On E85 this carb would ice up for sure my scooter grows ice on the inlet manifold just on a 50/50 mix.

So blowing nice warm air from the turbo through will produce a cooling effect from evaporating the fuel hopefully negating a need for an intercooler.

I also wont need to worry about feeding fuel through the turbo and grenading that under my ass if it backfires through inlet.

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Hmm yup if it lives about here i can refit the factory airbox holesaw a place for carb to poke its head out and get to the tuning nut by hand.

If only i had a holesaw set or a laser cutter to make some flanges.....

Only 30cm of inlet plumbing should make it punchy!

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  • 3 weeks later...

As a bonus was talking to a mate about building the drive setup for this how i was going to use chain etc..... he goes nah that'll be shit use these,

so will be rolling a 30mm cog belt as a primary drive hmmm wonder if i can get them to sing in a high C !

Some assembly required but ive now got access to a lathe at work so will be a piece of cake.

Oh and also access to a tube bender so the frame should be decent looking.

Have been looking to see if i can run any of my toys in the junior dragster classes at Meremere Dragway. Its a possibility but there's specs to build too more reading needed and im probably too old which means handing over to my kids...... yeah nah maybe will have to see what this handles like.

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  • 4 weeks later...

Have an abundance of shit on way from aliexpress to get this further along. 

Wastegate actuator is pressurized type as this turbos original was vacuume operated,  can be cracked open to change springs etc.

Belts to build primary drive to jackshaft where i'll run centrifugal clutches or gearbox depending what i can scrounge up. Might run 2 belts side by side if it looks too feeble ordered 25mm width. 

Have got a pipe bender available at work to do the chassis/frame work and also huge lathe!

The keywayed hub I'll turn down on lathe to fit the belt drive pieces on the motor. Its steel not cast iron so can be welded which actually was a prick to find.

 

 

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