Stroker.

[Genesis]

Hey all,

I was just wondering if anyone could elaborate on the concept behind stroking for me a little. I know it's a silly question to ask but what better way to learn?

What are the advantages of stroking over a supercharger or turbocharger?

I run a 308 VC Commodore and I'm just curious about what path to take in terms of performance. It's been suggested that I stroke the engine, but I'm not sure what this involves and how much of a performance gain I will get from doing so. How will it affect my fuel consumption/economy and is it generally worth doing?

My apologies for the ignorance, and thanks for your time.

 

[383 hatch]

The concept behind stroking is to get more cubic inches/displacement out of the engine, and you cant beat cubic inches! Stroking will give a power gain but the big difference in a stroker engine is the torque gain. You cant compare stroking to forced induction as they are 2 completely different things and have different advantages. Stroking is achieved by increasing the stroke of the crank and changing the length of the rods to increase the displacement of the engine. It is a really in depth subject to get into and there are different people around that have different ways of doing it, so do some ringing around and talk to the people who are doing the kits. Try come racing or crankshaft rebuilders as they have probably the 2 best kits around. Like i said stroking picks up brilliant torque and torque is what drives the car and frys rear tyres!!! Horsepower is good but you need torque aswell.

 

[Bakes]

As said above, stroking and supercharging are quite different. There is more to it than just building the engine though. If you think about when the engine is back in the car, a stroked V8 will look like a standard V8 externally, your insurance company, the RTA/ VicRoads or whatever and the police will not know any different. If you go the supercharger (or turbo), insurance premiums/ excesses will rise, and you will even get knocked back by some companies, the cops will be on your back, and if you get a canary, it will all have to be engineer approved, if not already.

Just as a bit of a side note, stroking increases torque greatly, and as any racer will tell you, torque wins, not hp (as VN Calais 5.0 said also). The disadvantages of stroking an engine is increasing the inertia of the rotating mass (from pistons and conrods being at a greater distance from rotating axis). This will result in an engine that wont rev as hard as a shorter stroke version, but for street applications, I doubt you will be pushing it past 6k regularly.

 

[Genesis]

Well, redline at 5.5 and with petrol prices the way they are, I rarely break 2.5.

Thanks to both of you for the explanations. I have always been a fan of torque, which is the sole reason I picked a V8 (other than the fact it sounds way better).

Your explanations have confirmed my thoughts as to which path to take. I'm sure I'll be able to discuss it with my mechanic and take it from there.

Thanks again guys, appreciated.

Just so you guys know, this is the engine I am playing with right now.

 

[Bakes]

Looks good mate. What displacement are you aiming for in the end, and what crank are you planning to use?

 

[scottm355]

Just remember that big cubes is good and there is no substitute for cubic inches but the horsepower of an engine is greatle affected by the cam profile, inlet manifold and the port design of the cylinder heads. No good putting a big crank in a motor that cant Breath!!!!!!!!!

 

[geardys]

and its also no good having an engine that make s#*tloads of Hp and nm way up in the RPM with bugger all down low. that is unless u have designed the engine for track work.