datsun 620 hayabusa swap

[datsunaholic]

Not saying that it doesn't have enough torque- it's a question if you can get a rear gear ratio that will let you actually drive it.  Wild stab here that the motorcycle engine would need a lot more gear reduction that a stock truck has. 

 

Having torque at 3000 RPM is fine.  But that doesn't do you any good in a 5MPH parking lot, which is needed for a daily driver.  A typical Datsun engine can be run under 1500 RPM to drive around a parking lot, or in traffic, etc as well as do 70 MPH on the freeway.  It's all about the gear ratios.  If a motorcycle engine starts making torque at 3000 RPM (which is only slightly below the normal CRUISING RPM for a Datsun) you'll have to have gear ratios to match the torque curve.  Or the planned RPM range, anyway.    Or you'll just be lugging the engine, or riding the clutch all the time.

 

It might work, but it's not going to give you better gas mileage, not by much.  The L-series engine isn't THAT much heavier when taken into account the overall weight.

[boarlin]

We built bike powered pull cars "tractor pull" when I was a kid. Plus my dad and I built a sand rail in the same manner, if you want put a car tranny behind the bike motor, it gives you reverse plus a multiple of gear options. We used a 50s chevy 3 speed, in reverse you can use all bike gears, and in the three forward gears you can do the same

[tr8er]

Couldn't a CVT transmission handle this?  I know they contribute significant weight, but it may be the best way to manage the conversion.  And if coupled with the bike transmission you could throw the bike into 1st as if it was an automatic.  But you would end up with an automatic.  You may not like that.  

[DRIVEN]

I say build it.

[datzenmike]

Best chance of success is to

 

Reduce weight dramatically. The more weight the more effort to move it and the gas used. If just wanting better mileage reducing weight would also work with the L motor.

 

Get the lowest ratio gear set in the back that you can find. For a 521 then a 4.875 from a 520. This will allow better starts (maybe) for a low torque/hp/RPM bike engine.

 

 

 

This is do able, but results will be dissapointing I think and this is why I advise against it. 

[K_trip]

- removed -

[mrbigtanker]

Just do it.Even if it works and i am not saying it wont or will,reducing weight and all that,it would be a lot of stress on that little motor dont you think.

 

But i would like to see the build thread. :thumbup:

[Layzboy]

And to the guy that said this project will never get finished i have only owned my z for under two years and have done more to it than 90% of datsun owners will do in their lifetime i dont procrastinate...

[q-tip]

Having a 240hp 170ft. lb. 'busa engine in a 620 will get it moving. I say go for it, if anything it will spin tire like no other :lol:

[GRpufnstuf]

My truck weighed 2260 when I weighed it to register in CA. That was 1/4 tank of gas in a '73 620 reg cab reg bed.

 

Lose engine and trans you're down to 17-1800, run a different rear end for the stock chain drive and Busa 6spd Trans the. Your lighter yet. I'd say check into the exile cycles F1 trike open diff rear end to start. Or tube it up and do a light weight iRS with a subi dif?

 

Then start making holes in the frame. It's boxed most of its length, you should be able to hole saw your way along the inner rails and get quite a bit of weight out without weakening it too much. Especially if you aren't carrying loads.

 

Now you can tube the front and back and get the suspension a bunch lighter.

Get the floor out of the bed and maybe acid dip the sides and gate to take a couple thou off the thickness.

No engine up front means no need for truck torsions, spindles, upper kingpin arms etc...

Lose Trans support and lighten or lose cross members and replace with tube.

Plexi rear and side windows, lose the regulators and do leather straps like old time race cars.

 

There will be carbon hoods and fenders soon from a member on here...

 

This can totally be done. Europe has all kinds of front drive subframe "drop in" conversions for mini, rabbit, rear drive for smart car. smart is my favorite, you get the same displacement 1.3L, nearly the same MPG, my 2006 Busa avg mpg was 34, and triple the HP (for the American version of Smart)

 

BUT, there is so much room in the 620 engine bay and so many engine options that are 'easy'.

IF you want lots of rpm and 240hp I would say grab an early 2000s Honda S2000 F20c and 6 speed, engine harness and computer and gauge cluster off eBay and you've got 9k redline in a very reliable non chain drive package

 

Huh, now I want to do it...

[dr.feltersnatch]

 

 

here is an interesting read

http://www.motoiq.com/MagazineArticles/ID/1519/Project-MiataBusa--Part-1-What-The-Hell-Are-We-Thinking.aspx

[datzenmike]

My truck weighed 2260 when I weighed it to register in CA. That was 1/4 tank of gas in a '73 620 reg cab reg bed.

 

Lose engine and trans you're down to 17-1800, run a different rear end for the stock chain drive and Busa 6spd Trans the. Your lighter yet. I'd say check into the exile cycles F1 trike open diff rear end to start. Or tube it up and do a light weight iRS with a subi dif?

 

L16 weighs 255, trans about 50. So maybe 300 pounds less the 150 put back as the replacement motor. Assuming this is a short wheelbase truck???

 

im going to be removing gas tank lightening up a lot of suspension components removing the heavy motor and trany to replace with my 150lb motor and tranny

 

So you are down barely 150 to maybe 2100. Long way from 1,700-1,800.

 

Then start making holes in the frame. It's boxed most of its length, you should be able to hole saw your way along the inner rails and get quite a bit of weight out without weakening it too much. Especially if you aren't carrying loads.

Sorry this an insane idea. How to 'lighten' the frame without weakening it and killing yourself. Get a motorcycle battery and throw away the stock truck battery. Take the heater out. Maybe front coil springs and rid yourself of those heavy torsion bars.

 

This can totally be done. Europe has all kinds of front drive subframe "drop in" conversions for mini, rabbit, rear drive for smart car. smart is my favorite, you get the same displacement 1.3L, nearly the same MPG, my 2006 Busa avg mpg was 34, and triple the HP (for the American version of Smart)

Yes, but none for heavy assed 620s. What does a Smart car weigh?

 

Yes it can be done but when done, will it live up to what you expect?

[datzenmike]

And to the guy that said this project will never get finished i have only owned my z for under two years and have done more to it than 90% of datsun owners will do in their lifetime i dont procrastinate...

What does this mean anyway? That you know 90% of all Datsun owners? Rubbish! 90% of our members have just been insulted. Most probably just keep them on the road but even that is a series of projects. Having a hard time reconciling "i dont procrastinate" with your user name. There are a lot of members that have completed projects much bigger (and much more sensible) than harnessing a bike engine to a 620.

[ggzilla]

A 170 lb ft engine is not 'low torque'.

[datzenmike]

Probably low rev torque is meant. If peak torque is at 12K it's not very helpful at 1K for pulling dead weight. Gearing will help here.

[ggzilla]

170 ft lb @ 3000 rpm is not 'low torque'

[datzenmike]

no it's not.

 

How the hell does 1,300cc make 170 @ 3K???

[GRpufnstuf]

That much torque suggests a turbo kit...

 

http://www.tobefast.com/velocity-hayabusa-stage2-turbo-pr-4279.html

[Tristin]

Since hes already mentioned that OP has so much fabrication prowess (a la his "lifetime" of Z work), how about he just builds it... needs to shit or get off the pot. 

[GRpufnstuf]

I can't get down with calling 2300lbs "heavy assed"

 

My '71 Volvo is about 2700lbs and makes 130hp / 100ft/lbs and it's a bit quicker than my L16 620 (granted my 620 is not running right, I think)

 

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I wouldn't hesitate to lighten the frame on these trucks. Especially if a decent cage is added

I've had many full sized American pickups with completely open frame rails. I'm sure the steel was heavier gauge than the 620 but I have never seen a more over built frame for an application so small.

 

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My stock 'Busa was 170hp or so and made just under 100ft torque. A turbo kit will get it to 240hp no problem and that would probably get the torque figure close to what he's talking about. But I doubt the 3000rpm, stock peak was 6-7k

 

The Suzuki 1300 and later 1380 are built stout. No trans mods needed until very high output ratings. Basic design used for small V8 race engines. 500hp bikes roaming the streets of Britain ( http://m.youtube.com/watch?v=kbSqhyJKET0&desktop_uri=%2Fwatch%3Fv%3DkbSqhyJKET0 )

 

I'd say a flywheel of some kind would be the best route for street-ability. Maybe run the Busa tranny in a fixed gear and utilize a standard car tranny for shifts.

 

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For the record, I don't think this a worthwhile project. Street-ability would be tough to attain and any truck application would likely be completely gone. If it's for drag or drift there are many better, easier and more reliable options

 

If it's just doing it to do it... Do it

[HRH]

It's definitely a cool idea, but I suspect without significant weight reduction you will have a couple problems:

 

1.  You may break stuff in the motor trying to pull excessive weight.  Kind of like using a Hayabusa to pull a travel trailer.  Just because it can, doesn't mean it will last doing so.

2.  You now have a truck that sounds like a Hayabusa but is still slow as shit comparatively.

 

I say if you're going to use a bike engine, you need to hit a target weight of 1500 pounds maximum.  Honda (no heavy rear drivetrain), 1200/210, something VERY light.  Or, do it and prove all us nay-sayers wrong.

[MikeRL411]

There's good ideas, there's bad ideas and then there's this idea.  I leave it up to time to tell how far below bad this is.

[Layzboy]

First of all i stated "most datsun owners" not "most datsun owners on here" so i dont get how thats insulting any one in particular andddddd From 3k rpm it made 170ft lbs so thats enough and datsun mike my username has nothing to do with procrastination as it is read LAY Z BOY as in a LOW Z CAR not LAZY BOY but thanks for trying to make me look bad

Heres my z its bot perfect but then again i took it from complete rot box to this

[Layzboy]

[HRH]

Nice z car, but seriously, wtf is that lighted dildo shift knob on there for? For fuck's sake.