Well,,, i`d say that a fully sick, mega U-beauty, Hi-reving, race type, twin cam, turbo charged, sequential injected donk would far far far out perform a 5 port.
Soooo,,, In that vein i can`t really go comparing the costs between the 2 different designs
However---> If, for example , you wanted to do a cheap boosted 5 port A series engine & then compare that with a cheap boosted twin cam conversion, then the 5 port would obviously be far cheaper & probably far better value for money
But,,, concidering all the niceties or benefits of the Bimmer conversion, the smoothness, the economy (when driven economically) the reliability, the power spread & power delivery, the flexability, the revability, the all round efficiency of it is obviously far far better than a 5 port & then you also have something a little differnt to everyone else.
It`s a bit hard to compare the 2 in any guise really as it`s not really comparing apples with apples, but i do get your point & to answer you question in relation to comparing the "cost" between the 2 (in all fairness) --->then the 5 port is "Cheaper" (Obviously there`s far less over all expense outlay)
It really comes down to a matter of """Horses for courses""" & ---> """You get what you pay for"""
Add some more time & money in the right places on any engine & you end up with a far better item, simple as that
Not everyone jumped onto the KAD twin cam heads when they were finally released & obviously for that very same reason you`re talking about... Not everyone is a millionaire & nor does everyone want a twinky either.
This "Alternative" is simply a far better "value for money" opperation for those wanting something like the KAD & or Jack Knight without the huge price tag. Maybe concidr it like an """In-Betweeny"""
(In-Bimmer-Twinky)
Adding a blower to the Bimmer is also just a more simple means to (1)- get even more power & (2)- Utilise the allready rather large combustion chambers without having to spend huge somes of money having hi deck, Dome shape, fly cut pistons, made up to allow a high enough compression for running them in Naturally asspirated form.
Sooo,,, i totally understand your view & am happy to suggest to any & everyone that if they want a cheap, go-fast mini, then the bimmer conversion simply isn`t for them (altho with a bit of nouse & simple engineering & mechanical skills, & equipment you can make a Bimmer twinky set up pretty dam cheap because someone like that can do nearly everything him/her self & save a huge chunk of money & end up with a really nice grunty, hi reving, hi horse power, smooth & quiet engine indeed. But not everyone is that skilled & equiped either.
Ok,,, so lets do what i don`t like to do (as i said above) Lets compare the 8v with the 5 port for a minute--> they both have relatively the same sized valves right? so you wouldn`t really expect much of a difference in flow between the 2 right? But that`s where you`re wrong,,, the 8V has far far better port angles & shapes & far far superior heat dissipation with the alloy, no cyl scavaging like the siamese 5 port does, cross flow configuration is a prooven high horse power high flow design, Pent-roof/hemi type combustion chamber shape with central spark plug location, all of which have been well prooven to produce better figures than other designs, & then we also have the fact that they all come allready fitted with the entire inlet system--> injection throttle bodies, fuel rail, fuel regulator, injectors, etc etc etc all ready to simply buy a computer & wire it up.
Now lets make that same comparison, but this time we`ll use the 16v head, with nearly twice as much valve curtain area than the 5 port A series
Hhhmmmm ---> YES, now we`re talking a totally different kettle of fish....
& now lets make it the later model 1200 bimmer cyl head version with even bigger cams & valves than the 1100,,, Hhhmmm---> YES, now we`re getting somewhere,
now lets add some decent sized ports & even bigger valves to that, add some wilder cams & add the blower then,,, yeah???
So,,, ---> your point is noted & agreed upon for sure, There`s no doubt---> A 5 port is obviously cheaper.
Now in saying all that tho,,, i know of quite a few very very high powered turbo A series 5 ports engines all over the world & nearly all of them have major dramas getting all that grunt to the ground & plenty of them are being beaten by less horse powered minis (& quite often mind you),,, That`s where the power curve or power delivery part & driver ability comes into the picture
Lets now add a traction control computer to our Turbo injected Bimmer twin cam conversion & suddenly we have bag fulls of grip--> "compared"
so,,, yes, it all costs money to have a blisteringly fast, smooth quiet yet drivable & reliable package under a mini bonnet.... & yes I`m afraid not all of us actually "WANT" that either
I do tho
Cheers & i`m glad you brought it up, it`s given me a chance to explain a few of those "Niceties" of the Bimmer twinky conversion to the general public (all be it a little long winded--> Sorry)
