Stroker or Forged, which and why??

[Sven777]

Didn't mean to step on anyone's toes here, just tried to keep it simple: an engine with a longer stroke works better at lower RPM as opposed to an engine with a shorter stroke. A longer stroke engine has a less broad power-band (effective range) compared a short stroke engine. Consequence of this is that the valves on the longer stroke engine (measured per stroke over the rev-range) will keep the intake valves open for a longer period of time (within the long stroke's effective range) as opposed to the short stroke engine; this benefit is a factor that has to be weighed in, especially on turbocharged motors.

This, combined with the higher RPM of the long stroke engine will indeed result in more power up in the rev range. At some point this power cannot be utilized anymore, and other (engine) parts become the limiting factor. At this point (we are talking serious builds) a stroker is the only option to increase power safely since there would be no additional HP to gain anymore by utilizing the advantage of the long stroke motor (intake valves opened for a longer period of time).

 

[The Doc]

So sven do you have experiance of a 550hp road car and dog gearboxes? A few members on here have exactley that on the pulsar and being honest they are not bad at all and off boost achive 39mpg on decent runs,if you know how to drive there is no issue,ckd a stroker again will be fine for what you want but you will need to match everything well in spec to get reliability as an every day car.

 

[Empty Pockets]

No worries, no toes being stepped on mate, i just don't see the logic in what You're saying regarding strokers in jap 2ltr drag cars, that's when you want revs , the rest is being taken out of context i assume as we're talking about a car that only gets revved to 7.5k anyway.

Peace and love to all, r.i.p spock.

 

[Sven777]

Not myself, although I have driven a 500 HP Pulsar before. I owned a stroked WRX for 3 years, so I'm not talking out of the blue here.

I agree with you, and that's what I said in the beginning: a stroker is fine for a weekend toy; but you need to make sure that the other parts match accordingly.

Driving a dog-box is no problem at all, even for a daily driver. It just that I purchased the full set and had a straight cut 5th gear in the box as well,that was a mistake, I do not mind the noise, but on the highway it was just causing headaches.

 

[Empty Pockets]

Don't think anyone's saying you've done it wrong Dan, and if they all revved to circa 8.5-9k then i wouldn't have considered a stroker for my use, just opinions based on observations, the way i'd go with this engine for my use, facts are, there's only two 500bhp cars on here as such, and they're both standard stroke, simple as that really, it's the best as it's the only tried and tested, up an running config, (that's a compliment btw)

Saying that, wasn't there another high hp build on the mod site, nd built with a precision turbo that made 500, think the guys username was jay maybe, what happened to that, and what stroke was his, wasn't that long ago, it made good numbers iirc and then it ll went quiet ?

 

[red reading]

Steve furgusons black car was a stroker with a gt35 and made 560hp don't know much more , so cant really compare as all other factors like cams etc are not known...will talk more in a while...no offence taken buy me ,just comparing a Subaru to well set up gtir is apples oranges .

 

[red reading]

Another thing that bothers me is making any more torque that a stroker may give 500lbft give my drivetrain a bloody hard time, most recent I have sheared a input shaft and pulled the centre out of a twin plate clutch which is getting plain expensive and annoying ( the gearbox did last five years to be fair) the clutch lasted 700miles this time! , I can see what your saying about more time for the cams to keep the valves open but a long stroke does not promote itself to high revs....I believe Norris found on his own engine he only gained 11hp and 8ftlb from a 2 litre to a 2.3 so that is not that great for the cost in the crank for our engine, the gtir head also has very large ports which don't have great velocity ( proven on a flow bench esp the exhaust side as the floor can be raised by a third before any flow loss is detected) the funny thing is the vvl heads the port is the same design and everyone raves on about them!, the only reason I don't bother to rev mine any higher is the torque and power are siting in the standard area and tail off just before the limiter so I would not benefit at all from it, a stroker will just move it further down if done correctly and put the block and drive train under even more stress.