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Discussion Starter #1
Anybody have any brand recomendations, I'm looking for an aftermarket crank shaft that will give me the highest RPM as Possible. I know that there's more to it than just the crank shaft by itself. I don't really care much about Low End Torque or Quater Miles.
 

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The stock crankshaft is pretty stout. Why is it limiting your RPM??


Dan
 

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here is mine crank shaft, connection rodes, pistons, flywheel all set, blueprint balanced 4 high rpms




allso head job, bigger, lighted valves 3angle, ported and polished, Kelford 272 9mm valve lift cams, titanium valve lush caps, etc etc,....
there is a lot 2 do to get higer and secured rpms


 

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how high do you want to REV to? I am using a stock polished crank and my car revs to 8400 RPM.


Dan
 

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MR2liter said:
Would It be right to say that the 3SGTE crank is a higher RPM crank then the 5SFE
The 5sfe is a beefier crank, probably capable of more abuse. The 3sgte crank revs higher in the engine because its a shorter stroke. ALl things being equal, if they were both 2.0L cranks, then the 5sfe would be better.

Dan
 

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Discussion Starter #11
I'll take all the help I could get, I'm looking at about 9-10000 RPM redline. The higher the better. again I preffer High RPM the Low end Torque.

Thanks everyone.
 

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toyota_3sgte said:
I'll take all the help I could get, I'm looking at about 9-10000 RPM redline. The higher the better. again I preffer High RPM the Low end Torque.

Thanks everyone.
Bore out your cylinders as much as you can, get yourself some shorter connecting rods. Custom pistons and new crankshaft for the destroked engine--might as well get in titanium. :) Probably going to need a dry sump setup- I don't think the oem oil pump will like those high rpms too long. Get some really durable valve springs, longer duration cams, good port work, probably going to need colder plugs with a smaller gap ( would not last too long under cruising conditions but should work better under WOT conditions), to make sure you get the spark quality needed you might even need to upgrade the ignition to a coil on plug setup and that might require you to get a standalone ECU. If your running the 3sgte I doubt the ct-26 will like or even be able to do anything but give off heat, so upgrading the turbo to something larger might need to be done. That would mean upgrading the fuel system, so now you need larger fuel injectors-- this now depends on the power you want. You can either get side feed or top feed. If you go top feed you will need an upgraded fuel rail ( don't forget to upgrade the fuel pump, return lines, etc).... this is a start at what you will probably looking at. This doesn't cover all of it, there is so much more you are probably going to need. If you reallly want to do this be aware it will cost money. How fast did you want to go again? :)

Dan
 

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Unfortunately I dont think theres a 2L crank aftermarket that you can get off the shelf.

Still, the stock crank unmodified has been known to see over 9000rpm without failure.

If it were me, I would use the stock crank.. have it treated however you like.. shot peen & cryogenic treatment is a good start. Then have it ground for undersize bearings. Most people will raise an eyebrow to that because grinding it will ever so slightly remove some strength.. but the advantage is that it gives you the opportunity to heavily chamfer the journals for more strength which more than offsets the strength loss from removing metal.

Then use the lightest rods & pistons you can while retaining enough strength for those RPMs (I suggest pauter rods).. this is important as the rods and pistons flinging around at those speeds puts a LOT of stress on the crank and can make or break it at high RPM.

Finally, make sure the whole lot is perfectly balanced, checked for straightness etc and if I were you, I wouldnt go removing a lot of metal off the counter balances on the crank. Its there for a reason.. and knife edging cranks is overrated. Last time I saw a formula 1 crank, it wasnt knife edged.

Given all the other goodies, I would expect such a setup to happily see 10,000rpm.

if you do want to try and reduce the size of the counter balances... the best thing to do is grind the radius down some, then have it drilled and filled with cintered tungsten (has a specific gravity of 14 I think.. very heavy). This allows to to reduce the size, but retain the standard counter balance weight

-Tristan
 

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The only aftermarket cranks that I have ever seen for the 3s motor were the impossible rare HKS crank (doubt that I'd ever see one again) and the outrageously expensive JUN crank (stroker). I don't think that either would "raise the rev limit", only add strength.
 

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you can get 1 made. I think th e company is scat and they also make light weight ones. if I remember correctly it'll be about $1000.
 

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NEAL CURRIE said:
The only aftermarket cranks that I have ever seen for the 3s motor were the impossible rare HKS crank (doubt that I'd ever see one again) and the outrageously expensive JUN crank (stroker). I don't think that either would "raise the rev limit", only add strength.
But the factor limiting RPM potential IS strength.. so increasing strength as a general rule will allow higher RPMs

-Tristan
 

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Basically, call that "scat" company, tell them wut engine you have, and try to get a 1.8 or less liter crank made. A 2.0 crank can prolly see 9000 rpm without too much hassle (of course, you must have all the supporting mods). But anything over that is definately going to be a stretch.
 

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Hrmm... you planning on just leaving it in 1st gear around town and never shifting? :p . Lol just playin.. but pretty much every question has been answered. And yeah, I'd go for a 1.8 liter, or even 1.6 liter, crank. Pretty much for those RPMs, you'll want the shortest stroke possible, but with the stock bore. This is how most all engines rev high. Short stroke, wide bore. Wider bore does make the pistons a bit larger, but this waaay offsets the stress on the internals than moving a smaller piston much further. Still, you will need prolly a few thousand in headwork (Ti valves / springs, nice cams, etc etc). I'd say you could get this all done for 10 thousand (reliably). That may or may not include the transmission work you'll need (syncros) to even be able to shift at those RPMs.
 

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Well just to put things in perspective. As far as internal engine modifications go, I have a metal headgasket, forged pistons, dual valve springs, mild port work. I still am using stock bottom end, stock cams, and my new redline is at 8400 RPM. I will finish tuning that car if I ever get a chance to mess with it again.
 
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