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Discussion Starter #1
Was wondering what the weak points of the later 600rr motor were, as I was considering a potential swap. It's a 91 NA6 miata that would serve as a shell for an engine swap. When most people consider swaps, the lower limit is to shed 300ccs and go for a hayabusa, as stock its torque is identical to the miatas, with a nice boost to hp and a weight reduction. I was considering going smaller, assuming I could get the torque to actually move the car. The next step down would be either an r1 or a 1000rr with a turbo, as they'll make more than enough power. I want to go smaller, to the 600. My reasoning is the shorter stroke will help with flame front velocity, as I want to rev. The 11,000 rpm of the hayabusa isnt enough. I found dozens of threads of people asking for turbo kits, but I can find a turbo and fab my own manifold. no threads speaking to what you could expect on a mostly stock bottom end, or atleast a bottom end using off the shelf parts, if there are upgraded main bolts and forged internals. The miata only dynos at 47 hp and 68 lb-ft of torque, and itll still break the tires loose on wet pavement. even being able to squeeze 180-220 horse would be more than plenty if I can breach 17k. Or do you think valve springs and a carefully balanced rotating assembly could see a 1000 to over 15k?

Strange question I know, this swap is a tentative future "upgrade" to my current swap, an NA VW v5 . By the time I would attempt the 600 swap, I would likely have access to a frankly over equipped machine shop and atleast a year or two of experience (I've already cnc'd the bellhousing adapter for my v5 swap in my highschool manufacturing lab.)

Edit: I also know i would have to change the hearing at some point in the drive train, as even with the 600's reduction from crank to flywheel, an artificially high revving sportbike motor would likely still output to many RPMs for the trans
 

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While the 600 top end horsepower gets you in the right area, you’ll be spinning the hell out of the motor to get close to there, even with a turbo. So unless you want to be constantly running at 10,000rpm plus and have the turbo fully spinning just to make the car actually move, I think a larger cc engine is a better choice.

You’ll be hard pressed to get the motor much past the 15k zone, another 500 rpm or so without major head work, so unless your very good with top ends, 17k will be tough. I think a larger displacement is a better choice.

A couple years ago I bought a new run-about car, a 2016 Chevy Malibu and tried out the 1.5L version when it was first released. Hated it. Off the line, around town, basically anywhere the engine wasn’t revving and the turbo wasn’t fully on and helping it was a turd, though when the turbo kicked in it would propel you adequately. It was just a frustrating drive unless you were able to spin it up and go.

Passed on it and started looking at other vehicles. Loved everything but the engine.

I drove the 2.0l version a few months later and immediately bought it; the 2.0 had enough juice to actually propel the car and get it going when the turbo wasn’t “assisting” then when it did kick in it’s a smooth, very fun mid-to-top end rush that was linear.

I feel like you’re looking at the same thing, only worse, with using the 600cc motor. it’s just so small without the turbo you’ll struggle to make power. I get doing things different than everyone else but sometimes there’s a reason they do it a certain way.
 

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I fully intend to do head work, not just to increase the rev limit, but also to increase bottom end power, I also plan to go with an undersized turbo to build boost sooner. My a4 uses this approach to build boost at 1600 rpm. I dont intend to use the high revs, as there also isnt much torque up there and consequently, no power. Just wondering about how much torque the 600s bottom end will take before I start launching rods or snap a crank. A modern 1000 will do the part just fine, as people are using early 2000s hayabusa 1.3s (like 03-04) and keeping them naturally aspirated. Infact turbo'd you can actually make more power than the 1.6 that the car currently has.
 

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so you need to build it to increase the rev limit, but you don't intend to use the high revs.

what?!



and no, a 600rr engine isn't a good application for a car. the load on the crank (due to the mass of the car) is far in excess of anything it ever sees in a motorcycle. you'll twist it off if the clutch holds.
 
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