pristic wrote:
While the bikes make power at 9500-10500rpm
Pete
BMW K-series --> only 987 cc...
Max Power--->90 hp (66 KW) at 8,000 rpm
Max Torque--> 86 Nm / 63.42 ft lb at 6,000 rpm
Compression Ratio--> 10.2 : 1
It`s a really "Little" motor boys & girls,,, it`s "NOT"-->"""designed to do A Zillion Revs""" ,,, but Doc you are right in one respect with the cam designs,,, they are not a perfectly suited profile (YET),,, they have not yet been "perfected" to suit a mini engine "YET"... but isn`t that exactly what GR is doing??? ---> In fact still trying to perfect cams to suit the mini engine???
Like i keep saying boys & girls,,, GR is doing good things & i agree with what he`s doing,,, I`m defiantley not knocking him,,, I`m all for it & it`s exactly why i like to build really big donks with mild cams,,, effectively achieving a similar power spread as what GR is trying to achieve,,, Crickey,,, how many times have i said exactly that??? Id dearly love to have a smaller engine with the same (or better) power characteristics as my 1415cc & 1510cc engines---> Who wouldn`t?????????????
sorry if some of my pot stirring is sometimes taken the wrong way,,, i`ll back off "playing around" now, just to keep the peace,,, but If you guys just stop to think about what you`re saying with all this 10-11-12,00rpm stuff & how the mini can`t do 10-11-12,000rpms,,, well i`m sorry but the Bimmers are set up with small ports,,, small valves & run "up to" 8000rpms ,,,
they are a very very mild beast indeed,,, very very drivable & smooth & absolutelky no need to rev the tits off them at all,,, just because they "CAN" run up to 8000rpms doesn`t mean they have nothing down low, nor does it mean their power spread is useless to the road driven mini,,, in fact it`s quite the opposite,,, they have a lovely power spread & soon there will be cams avaliable for them which will be far better suited,,, they`re being "Played with" now & have been "played with" for quite some time,,, (In fact by a number of different companys) just like GR has been "Playing with" (Developing) his new range of cams
the K1200 head is a totally different kettle of fish tho & yes it`s far better suited to the higher end of the rev range... but they are still VERY mild in there cam profiles
again it`s only a little engine at --> 1171 cc
Max Power--->130 bhp (96 KW) at 8,750 rpm
Max Torque--> 117 Nm / 86 ft lb at 6,750 rpm
Compression Ratio--> 11.5 : 1
Now if you just stop & do the math,,, lets now add the size of engine that GR is "Playing with" --- a 1380cc,,, sorry ,,, what was that???---> A 1380cc
OH!!!!!!!!!!!!!!!! well lets add that massive chunk of capacity into the equation now shall we??? lets now just add that massive chunk of low rev air speed increase into the mix shall we??? Now we suddenly have a far "Bigger" pump havn`t we??? We are now passing WAY more air into the engine at the same rev range yeah??? Please someone tell me i`m wrong here????
Now, so far in this particular example i havn`t said anything about increasing the revs to the moon (Just yet)
so do the math now & see what those std , very mild K-1200 figures turn into "simply" by adding that big increase in engine displacement yeah???
do nothing else ,,, just add one 1380cc pump underneath that std K-1200 cyl head yeah???,,, well---> more like 130+hp & approx 110-ish ft of torque,,, still within the same rev range, still with a stock head
Now lets "Play" with the head (like GR is doing)... & there is much we "can" do but (if you`ve ever looked inside a K head), you will see one simple problem imediately which is soooo easy to correct & adds a whole bundle of power without having to increase revs.... It`s so simple & easy to fix it`s not funny
& then lets say we "PLay" with the cams (Like GR is doing)... ok, now we see a even more improvment (just like GR is finding)
BUT,,, that`s not "REALLY WORKING" the head at all is it,,, it`s just fiddling with a fiddly little lip problem,,, there is "PLENTY" more you can do with them to help bump the power again & still remain in the std-ish revs dept,,, there`s more work with that side of things happening on many many twin cam mini heads all over the world at the moment (of which we hav`nt seen the fruit of yet) ,,,, they`re a relatively hew thing compared to the age old suffocating A series head that`s had soooo much work on it for soooo many years,,,,,, so maybe you all should cut the twinkys some slack yeah??? They`re new & it`s exciting & there`s "OBVIOUSLY" plenty more to come from all the various twin cam heads ,,, as is the same with GRs work & the Elder 7 port,,, lets all just be nice Boys & girls,,, lets stop the arguing now,,, lets just go about doing our things & it will all come out in the wash,,, I`m building turbo injected twin cam engines,,, GR is doing push rod 5 & 7 port N/A engines
... it`s not apples with apples,,, it`s not even apples with oranges
This whole discussion has gone way off topic from GR playing with 7 port Elder heads ,,, through to GRs cams for early 5 ports,,,, & now we`re back with all sorts of crap about which type of head everyone prefers,,, cool,,, but no "One Particular" cyl head is going to be fitted to
"All" A series mini engines for the rest of all eternity,,, there will allways be some one finding Somthing else to fit & "Play with"
If we didn`t have a play with minis,,,, then GR wouldn`t be GR,,, David R wouldn`t be David R & i most certainly would be playing with turbo 4x4 GTR skyline running gear underneath duel cab kombi utes instead
get back to work you bludgers
& GR,,, definately no offence intended,,, & i know you know that already,,, just want everyone else to understand our relationship is good.
see you at the Hyrtericals at Morgan Pk