sparetireless

Could a semi-reliable 10k RPM motor be built? Seems like the main weak points are rod bolts, and valve float, is there anyway around these week points.

I would like to build a motor like this just for the challenge of it. Any suggestions ?

Steve Weiner-Rennsport Systems

This depends on the displacement but in general, 911 air-cooled motors do not make power beyond 9K.

8K operation requires a LOT of extensive modifications and is a very high budget project. There are ways to deal with the weak points, but its very expensive to do this right

sparetireless

What if we started with a 3.6 motor, take it to the 2 liter range, would that be a starting point?

The power will be what ever it will be, thats not the goal necessarily, how can we get to 10k rpm without the motor failiing?

Steve Weiner-Rennsport Systems

One can do almost anything if there are sufficient resources to meet the objectives.

I would not use a 3.6 to build a 9K to 10K RPM engine. There are better platforms to do that.

I don't think any air-cooled 911 motor beyond 2.2 litres will rev to 10K (on-purpose) due to head flow limitations and frictional/parasitic losses. These engines occasionally see beyond 10K but thats due to missed shifts more than anything.

fork_included

you buy yourself a civic B16A engine, and you balance all the internals, the engine will spin to 10K easy

put a huge camshaft on it (290+ duration) and it will actualy make power at that RPM


having a car thats undrivable cuz it has no low end power....

sparetireless

What do you feel is a better platform for a high reving project? I am after a sound like the 917 if possible.

Tim

9000 RPM Turbocharged 3.8

9000 RPM

The crank was reground to use Clevite NASCAR bearings, Pauter rods that accept the NASCAR bearings, etc..

Steve Weiner-Rennsport Systems

I would use a big bore/short stroke combination with long rods & custom pistons, for a starter.

The only way you replicate a 12 cylinder engine sound is to build or use one as thats VERY distinctive.... 917's never went over 8200 without failure,....

Ed Newman

You are missing a few pieces of info... size, HP, what is reliable, reliability vs durability etc. There are a long list of motorcyles that run 10k plus RPMs and are very reliable and durable and even come with a warranty.

sparetireless

how much boost on this one?

sparetireless

Some rev. to 14k all day long, how do they do that??

por29

Timmy !!!!! What the...

10 GT3

This is really a moot point as the initial issue isn't getting one to spin to 10K, it is getting one to pull out there. Here is where you can start. Buy a 997 RSR crate engine. The bottom end should be in good shape to take 10K out of the factory. Get a reputable builder to do a good porting and port matching on the heads. Fabricate a short ram intake. Find someone to grind you out a set of 300+ degree penut shaped cams and go for. Look at a top-end engine management system like a Motec. If it can pull to 10K, you will be putting out well over 500 hp peak with just 3.6l. Should be an interesting project, not cheap, but interesting. It should be realiable, but not probably driveable on the street.

The comment listed about a Honda B16A engine with just balancing can reve to 10K is somewhat true. It can do it once. It can't do it without the cylinders walking, distorting and leaking out all the cylinder pressure. The B16A, like all Honda B-series blocks, is open deck. It is their biggest flaw and why there are several manufacturers making aftermarket blocks. The cylinders are over half exposed. In fact, they are only secured to the block at the bottom of the cylinders. You have to get darton sleeves or weld a block guard in just to stabilize the cylinders. Darton sleeves are the best option as the stiffen the lower end of the block, where the water jackets are also known to crack under high pressure. Neither the the stock rods or the crack are up to it either. Stock cranks can break at the journals and the rods are too thin at the crank end. They were designed to by light weight to make it easier to rev to 8K, not 10K. Fortunately, there are many aftermarket manufacturers like Eagle who make very inexpensive upgraded cranks and rods that can fit this purpose. If you really just want to rev, just put a Honda Blackbird engine in CRX.

If you want reliability and much greater power than you could ever get with the reving motor, go low compression and boosted. That high-revving RSR engine can't even match the power of a stock vintage 930 engine with upgraded headers, exhaust, fuel and a good size upgraded turbo. To finish the Honda analogy, a fully built for racing high-revving LS/VTEC engine can't match the output of a smaller displacement 1.6L SOHC with a bolt-on turbo kit that is a fraction of the cost to build.

sparetireless

Dumb question, is it really possible to buy such and engine? From a dealer? Who can you recommend I get a quote from? Seems like it might be cheaper than my learning it all the hard way.

Thanks,

Steve Weiner-Rennsport Systems

Contact Porsche Motorsports,........be prepared to spend really BIG money,........