mg cams
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when it comes to a rapidly varying air density ,pete ,and the acompanying change in resonant frequency points , i think that some of the theoretical equations are sadly lacking ,without including a density compensation factor,when engine modelling i tend to vary density and air temp along with volumes and tuned lengths to get an average ,.
bear in mind that a loss due to a large port somewhere ,will prob be a gain at another point in the torque curve area ,and may be more suitable for certain occasions, if the engine is operating in a state of harmony at say 5500 then yes it may have produced a bit more at 1897 rpm ,but its not a big loss.my point about the valve is that at high lift ,the valve can still be a flow aid ,not a detriment ,and ports can flow more at high lift with the valve in than without ,so if you lift too high ,you can reduce flow .the other comments on r nos and so on and port size , i think really apply to all engines ,,to small chokes rpm ,too big soft bottom end and reversion due to low inertial control ,with ref the theory on the intake pulse effects denuding the adjacent cyl from its fair share of the plunder ,hmm the first thing that jumps to mind is the cross sectional area change as the neg pulse travels back from the port its increase would slow down the pulse and deplete it a little ,also if a pulse travels to a point of cross sectional increase then reflects a positive pulse back with its inherant air density increase wave ,then couldnt the port plenum be that cross sectional increase ,therefore creating a pos pulse just coming back to the port as the valve opens , the concept of the sonic pulse having a bigger effect than the ram inertia i think may be unlikely ,but sounds like a fascinating idea ,bit diff to prove though !
regards robert .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

think this may be getting a bit techy , what do you think ,dont want to bore everyone into an early grave ,,,you may be intersted in my t25 500cc bike ,that iv got boost coming in at 3800 using various techniques ,pk power 135 on 15psi at 10100 pk torque at 7100 ,so as you can see the widening of the boost power curve envolope is a subject iv been at for a while .lol

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

And you see folks , there is tuning and there is TUNING.....

I for one thought that was great reading.
Mini1071 its nice to know your out there matey good luck on the 998 T.
Ivanhoew what can i say , i will tilt my hat ,ah no i will bendeth down before you,waiting to kisseth those golden hands....Get off this forum and put that intercooler on your mini .

I know , i know im sorry , it just makes me grin !!!

Intercooled 1293 cc Turbo +
March 06,4psi and counting .
Its now gone up to 8psi.
Nov 06,10psi +.
And now part of the Airbourne club.

Oh and calling you an expert,,, lol......

Mini1071 you have made his day,,,no week i should think.

To be fair , i couldn`t of built all of my cars with out you, Ivanhoew ,(well ok the first three i did, but)so i have decided to get you some more overalls with expert on them,for your birthday,,ok.So i can find you in the garage,,ha ha ,,,,,lol ,,,oh i gootta go ,im gonna piss my self laughing...

I know , i know im sorry , it just makes me grin !!!

Intercooled 1293 cc Turbo +
March 06,4psi and counting .
Its now gone up to 8psi.
Nov 06,10psi +.
And now part of the Airbourne club.

thanks for the compliment pete,i have a lot of projects in my head at the mo so a bit out of date mini wize at the mo ,its good to have contributed to a forum that has such an avid interest in walking the fine line between torque and termination !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

yes please keep you hand in ivan.

have you! any prefrences for the A series cams out there for turbo charging. ?

or could you improve on the top 3 say. ?

Edited by BENROSS on 14th Mar, 2006.

Well I've read this whole thread from start to finnish, and very interesting it was too.

But until pete's or Ivan;s cams come to fuition, stick an MG cam in and you won't be diaaspointed. My old 998 engine produced 140 bananas with it and a standard 940 head, and that was good enough for me.

I'm sticking with the MG cam in the new 998 and loking for 150 bananas.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

will do!

thanks ben ,iv not really done a new model or the higher boost engines ,the cam i had made was done in 98 for a car built to keep below the 120 bhp lb ft barrier i felt was needed for the transmission being stock and it was a work car to be used in all weather ,so it was 3.5 psi simple engine ,that cam made 114 bhp at 6100rpm ,with a 9.4 cr ,and 40 mpg ,.
now i have the car back after it being away for a few years i may develop it more if i have the time ,but ill see how this cam does with more boost porting and lower cr ,its quite different to the ph 2 ,if the measurements iv seen on here are correct..and ill see if it works as well as it did on the low boost ,i should really design a new one ,but im interested in a possibility of a dual purpose cam ,iv also timed it in differently to enhance high bhp .as usual on a project i own ,i can try stuff thats a bit outside the envelope and if it doesnt come up to expectations ,theres no customer to moan!!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

ivan would be nice for pete & you to re cofiguring the phase 2 or kent 266 cams & producing a new one!

pete i have cut a few heads in my time & still do a few a year!

i have fallen into the trap with port velocity for diffrent kinds of motors & i have more or less cracked it for turbo road motors now !

On 13/03/2006 21:33:37 mini1071s said:

The roller followers are very interesting as they almost eliminate friction losses - 75% less at idle and 35% less at cruise speed. Thats why the OEM's use them in pushrod V8's like the LT1, (drooool).


Not the one I am using BTW.

Metro turbo weekend driver,Mini turbo in the making again!

looks good to me

1293 Turbo mini