Have any of you put a stroker kit in your cars? For those who don't know what it: A stroker motor is an engine that utilizes a different crank to achieve more displacement with the same engine block. An engine fitted with an altered crankshaft that has a larger stroke increases the engine's size without increasing the size of the block.

It seems like a safe and easy way to increase engine output with out raising any Bars(psi).

Does anybody offer a stroker kit?

 

Not only would the cost of the crank be expensive, but how are you going to clear things like your oil pump etc. There isn't much room/clearance available.

 

it fits inside the block, and shouldn't take any more room that the current crank.

 

FVD has a kit for the TT if I remember...

 

One thing I always wondered about ... with a longer stroke, how does the piston not bang in the head and valves? Or drop out the cylinder at the bottom? Wouldn't shorter piston get much more stress (especially considering the extra angle)??

 

We do it to the older motors all the time. It just requires that we change the offset of the piston wrist pins. The mains will remain the same in the crank. It is the stroke that changes therefore no real internal modification is needed. The key is in the rods or pistons or both. I haven't done a 996TT Stroker yet,. but the old stuff just requires a special piston and it is all good.

 

If a stroker is accomplished by just relocating the crankshaft's
piston pin outward (using the same length rod), then the piston
would go higher into the cylinder (raising the compression ratio
into the stratosphere) and go lower into the crankcase. In order
to avoid the compression issue, the rod length can also be
shortened a bit, so the maximum height of the piston can remain
the same. This will cause the piston to drop even farther into the
crankcase at BDC. Sometimes you can use different pistons that
have their crank pin located higher up in the piston.
Stroking a motor is good for getting more power at lower RPMs
but not as good at higher RPMs because the piston speed has
been increased, and the piston-to-cylinder friction is increased
because the maximum angle at which the con rod presses the
piston (relative to the direction of the cylinder) is higher. Ie:
when the piston is half way up it's travel, the conrod is pushing
it more sideways than a non-stroker. Some folks will actually
go the other way, destroking some motors to get a higher-reving
motor. RPMs = power too.
Joe

 

Correct, We started doing this since the low end lacked due to lower compression. Remeber that the earlier turbo motors were 6:5:1, 7:1:1 and 8:1:1. Years 65-77, 78-89 and 94-98. The typical corse is to have a set of pistons made, ues the same rods then have the wrist pin offset to acchieve the proper travel. The reslut is a better low end torque band and better off thorttle drivablity.

Keep in mind that the 996TT carries 9:4:1 and the lift and timing of the cams is changed to achieve a broader more usable powerband. Most turbos do not have the drivablityof our cars but when your lift changes from 3mm to 10 to achieve a better low end and great top end. I can't say that it would be nessasry to do it to a 996TT twin because of the active valve train.