Facts you may not know

[PWRDbyUNCLEbens]

I was under the impression that sohc were typically three valves per cylinder. Two intake and One Exhaust in that case it does make sense to have an sohc engine.

I find it funny that the new 4.6 just now came out with three valves.
Honestly I didn't know the old 4.6's were two valves till I just looked it up. I guess they made it so just for a smoother running engine, and for the advantages already stated.

I thinks it's cool how the ZR-1 was so far ahead of it's time. Granted the new Z06 is nothing to scoff at it would have been interesting to see where they would have been now with the dohc set-up.

[TatII]

the v8's rev limit is limited to the weight of the internals plus the stroke of the engine. my proffessor got his 500 ci mapr block to rev to 8K in his hot rod. the main problems that i would think is hydraulic liftes sticking at higher rpms, and such, that is also another factor that might limit a v8's rev limit.

[CBFryman]

Originally Posted by drftk1d

it doesnt rev THAT high. on my n/a motor redline is 7k and power falls off around 6.5. The limitation is the stock port size. If the ports are made bigger than it'll rev that high and actually make power up there.

with my turbo motor, it has porting so the redline could be higher than stock but the stock turbo (which i'll be using for a while) falls off around 6500 rpm as well.

and i dont worry about apex seals too much cuz i take care of my shit!


btw my insurance is actually fairly low.

edit: red my fault about the z06 comment. i was trying to refer to the higest performing corvette under the ZR1

i said it can, with modification...well more than some, but Wankles can do 11,000 RPM in a "daily" driver (more like a weekend driver) no problem. ive seen some take redline as far as 12,000 but for the most part you only take it that high because your powerband is naturally so high and you have to have such a large turbo to run massive ammounts of boost that it doesnt even start making boost untill pretty hgih RPM's... but 12k is pretty excesive. either way...my insurance for my truck is around 1300 a year...for a 2nd gen 7 it was going to be over 2k a year.

[TheStang00]

well wouldnt an ohc engine also rev easier due to less moving parts, less weight. nascars (yes i know theyre racing motors) rev to 10k in v8's. and those indy cars, well they rev to rediculous amounts if im not mistaken

[CBFryman]

but indy engines are deisgned to last 500miles, no longer, they also cost hundreds of thousands just for the engine and are short stroke wide bore V10's that are limited to 3.0l and only rev that high because they are trying to make 700+ HP with only 3l of displacement and no FI. Nascar motors are also only deisgned to run one race before they are rebuilt... hardly compareable. and Indy cars use electronic valve timing, from what i understand it is 100% controleld by a computer, nothing mechanical connected to the crank involved.

also, from my understanding indy engines IDLE at around 4,000-5,000 RPM and dont hit their power band untill between 10,000 and 15,000 and redline as high as 21K RPM.

[drftk1d]

Originally Posted by CBFryman

i said it can, with modification...well more than some, but Wankles can do 11,000 RPM in a "daily" driver (more like a weekend driver) no problem. ive seen some take redline as far as 12,000 but for the most part you only take it that high because your powerband is naturally so high and you have to have such a large turbo to run massive ammounts of boost that it doesnt even start making boost untill pretty hgih RPM's... but 12k is pretty excesive. either way...my insurance for my truck is around 1300 a year...for a 2nd gen 7 it was going to be over 2k a year.

if your peak power is 11k then its probably a bridgeport or half bridge. Thats close to being unstreetable. you have like no power below 3k in that instance. you have to understand that rotary engines have linear powerbands (the power rises as rpms rise, thats the reason why the engine design was originally used as a supercharger). when you port it, it shifts upward. you lose the first 3000 rpm but gain them uptop. it also causes you to idle higher as a result (and you get that fucking badass idle). i hope that makes things more specific.