what is the reasoning with a few extra cc's being thought of as voodoo engine magic? it's just a slightly bigger displacement. the equivalent of adding an xr50 or xr70 amount of displacement isn't enough to change the whole package so profoundly for the better.
ever see a small block smoke a big block? it's setup, not displacement that makes the biggest difference
That's an old, tired saying. There are actually several replacements for displacement. Power adders such as nitrous, superchargers, turbos, etc are all effective replacements for displacement. So is compression, proper setup, and technology.
Ever wonder how a 1.7 liter Honda 4 cylinder engine can put out more HP than a mid/late 70's 5.7 liter Corvette engine - and do it without any power adders?
Ever wonder how 450r or YFZ can blow by a Raptor in a drag?
If my properly tuned 500 setup makes 45 HP, I'd really like to know what magic they're performing to get 15 more HP out of 20 additional cc's that takes the engine 20 more cc's beyond it's original design parameters (i.e. carb, head, exhaust flow).
They're blowing smoke with their dyno numbers. Expect only a very small increase in power over the bore only 500cc setup --- the biggest effect on acceleration will not come from the additional cc's, it will come from how much lighter your wallet is from paying *WAY* too much money for way too little gain.
In reality, you can expect a little less than 1 HP for every 10 additional cc's in one of these engines (very simple math, think about it) --- as you get bigger and further from the original engine's design parameters, it will take more cc's for every HP you wish to gain with displacement alone.
All things being equal - cylinder head design, compression, cam profile, induction, exhaust, volumetric efficiency, etc. - displacement is probably the cheapest and most reliable way to boost power - to a point.
As you mentioned if you go way beyond the original designs capacity for fuel & air supply you are wasting money and time. But I think when I decide to mod my R's motor I will get a mild cam and bump displacement. Dont want to be messing with race gas and elevated cylinder pressures which shortens the life of all engine components drastically.
On the comparison you guys did which yielded similar power gains, which was the most economical? And which do you think will have better longevity?
86&Mixxer, I respect both of your opinions as you both understand the workings of motors way better than I do. That is one of the many reason's I ask questions on this site. If either of you go to planetsand.com you can read all of the ramblings about this setup, I dont recall what all they said they did to the motor. I didnt think their price was too out of line. When I spoke with FST that is close to what Mickey quoted me for all of his parts.
Also 86 are you going to be getting one of the high comp pistons that KGB has been working on? I would be very interested to see what type of real world difference you see and if the extra comp. is worth the extra$$.
All things equal - yes, a larger engine will typically make more power -- but that's not what you said initially, especially in the context of a motorcycle engine with limited head, intake, exhaust, and valve configurations. No replacement for displacement suggests that if you have a bigger engine, you'll develop more HP and that's not a true statement.
I did a 500 setup @ 12:1 because at the time there were very few acceptable choices out there & it sounded like great bang for the buck. Another reason is that sometimes race gas is difficult to obtain around here. It's also very easy to go back to stock or stock bore high compression if I hit a National with CC limits.
I don't think increasing the displacement and going with a mild cam is the way to go - especially in one of these engines which was developed to turn a lot of RPMs and develop power up high - if I wanted a big CC, low end tractor, I would have bought a Raptor or DS --- or tricked out my 400EX further.
Nmotion's setup at $1000 is roughly double what the FST setup is because you must replace the cylinder with their custom casting - I spent less than $500 on mine & that was including an extra $30 charge for pre-shipment of a cylinder so I didn't have any downtime beyond the evening it took to do the swap.
I personally don't see a bit of sense in doubling the cost of the setup for the additional gain of a mere 20cc's --- not to mention that you have to bore the cases (i.e. "simple case modification" as mentioned on their website), which means you have to split the cases, remove the transmission, crank, flywheel, etc, and take the bare case castings to a machine shop.
The engine being discussed on planet sand is much more than a simple "520 bolt on kit". If you do those modifications to a high compression stock bore or a lower compression 500 setup you will see roughly equal power at a savings of over $500 - that's like getting an FCR carb setup for free and getting some change back.
Bottom line is you are spending a WHOLE LOT more money for a 520 setup than a 500 setup for VERY LITTLE gain. A new cylinder casting is not going to do anything for power compared to a stock cylinder casting --- this is not like swapping cylinders on a 250R or a Banshee.
His dyno readings are high for all bikes tested, so that must be taken into context as well.
86, thanks for your input. As Mixxer has said you are a wealth of knowledge. I think I am going to get the FST kit and go with either the x2, x3, or sparks race cam. Not sure about compression yet. If I go high comp, I'd most likely have the flywheel lightened 4oz. I ride mainly in the sand so I think this setup would work great for hill shoots and drags.
Thanks for sharing your info. Your research and posts have helped me in making a decision. Race fuel is easily accessable for me so the high comp shouldnt be hard to satisfy. Do you think lightening the flywheel with the high comp. would work well?
Ya I saw a dyno sheet from them of 59. I dont live to far from them about 2 hours. From what John was telling me they do some heavy head flow and larger valves. A radical cam and I was thinking 12.5 piston.
Did not see the torque of the motor. I was talking to another pro that knows the setup they have and tells me it is low on torque. I saw the 54 dyno sheet also and it only had like 30.7 torque. Seems very low to me. They are using Webcams and Je pistons. They had everything there except the cylenders when I was there last week.
That is all I remember. Call John he is the owner super nice guy.
<edit> and the $1000.00 I think only included cyl. and piston.
if i had known the specs were as rad as they are for the hrc, i never would have done all the extra work to fit the x1. it was a LOT of extra work and needed springs. i prefer not to use stiffer springs if at all possible due to the extra stresses on the cam chain and valve seats.
As mentioned above,its hardly a 520. It has everything done to it as well. Froma custom designed pipe. Cp industies made the casting, which should be good.
Just bore your stocker to a 99mm bore and save the dough.
To clear any confusion.....I am having nothing to do with a FST 500. Mickey Dunlap did his own research and development and has made a very attractice product. I am not claiming to or wanting to steal his idea, or knock it off.
I simply am able to get a 99mm bore 2 ring piston in a 13.5:1 comp ratio becasue I have a friend who works at JE pistons.
I do not want anyone to get the idea, that I can get you a FST kit for cheaper or anything like that. That would be wrong, and if you want a 12:1 99mm bore call Mickey Dunalp.
Email me at [email protected] to anser any questions, it is not necessayr to clog up the boards. I am not a sponsor, I am not making money, I am not a retailer, just trying to help some friends.....