ausmini :: View topic - Mini Forced Air Induction

Actually when you read a bit deeper into the engine turning around stage of design most of the people involved have admitted it was for the improved gear train in the drop gears as a single drop gear was failing . According to Garfield's book I'm reading at the moment they didn't encounter carb icing up until they turned the engine around .

There is no need, the air pressure coming in through the front grill forces cool air into the carbs anyway. It comes in through the front and gets forced out the side radiator and down the back of the motor and under the car again.

sports850 wrote:

Oh ok,, Cool,,, I just heard what I wrote In the "John Cooper" DVD or "The best of the Origianl Mini" but that could be the case. They do still ice over the way they are (I'm told) in their current position... It just seemed relivant.... Have you read yet that they got better mpg with it the way they had it first? Kinda funny hey

So mstmini,,,, How's that prototype coming along?

Phat Kat wrote:

sports850 wrote:

They had more power as well with the motor around the other way , the extra gear before the gearbox robbed that little bit more which was enlarged as a percentage once the drive had gone through the gearbox .

The carby ice story was a deliberate "myth" to hide the gearbox problems that came from using existing gearbox internals with two heavy primary gears acting as extra flywheels.
The motoring media knew that the prototypes had the carby at the front and then suddenly they had the carby at the back. The media needed to know why they changed the whole layout so they came up with a cover story!

The Austin Maestro/Montego has the carby at the front of the engine bay on an A-series engine. :wink:

Author:	mtsmini [ Mon Oct 12, 2009 3:02 am ]
Post subject:	Mini Forced Air Induction
Why has nobody ever developed a ram air system for a mini It seems a bit strange that we have backward facing carbs in a hot engine bay when a bonnet scoop or a behind the radiator air collection and delivery system could deliver cooler air at higher pressure directly to the carbs. Must be a reason

Author:	Asphalt [ Mon Oct 12, 2009 5:36 am ]
Post subject:
Minispeed germany once sold a RIS (Ram Induction System). http://www.mini-mayfair.net/temp/ram.pdf I've been told it worked realy well. Consited of a cast plenum chamber and a pipe to the front with a big air filter. This RIS is actually a re-designed, improved copy of a system sold by K&N untill the early 80s. But I guess it was never very popular since it was expensive. Cheers, Jan

Author:	Mini Mad [ Mon Oct 12, 2009 9:40 am ]
Post subject:
There is no need, the air pressure coming in through the front grill forces cool air into the carbs anyway. It comes in through the front and gets forced out the side radiator and down the back of the motor and under the car again.

Author:	Phat Kat [ Mon Oct 12, 2009 12:55 pm ]
Post subject:
Interesting fact for you mstmini... you might already know... The first prototype minis had the engine mounted the other way round with the carbs at the front... Reason they turned it around is cos the carbies kept icing up.... But its a cool Idea though, it does still get pretty warm in the engine bay, especially with the carby sitting right ove the top of the exhaust (and you know hot air rising).... Maybe you could dream up a crazy solution and post a pic with your invetion in the "crazy backyard s**** that should work... but did" thread (sorry guys, I had to put a plug in there for my thread ) The K&N one that Ashphalt mentioned was pulled from production (as I uderstand it) because it was too efficient (basically).... The piston in the carby was rising faster than the rate of acceleration so you couldn't get the full effect until the speed of the motor caught up to it,,,, , Don't know if I wrote that in a way that made sence... I think you could cure it with a heavier spring or heavier oil... Don't know.. Someone who will remain nameless will probably come on and correct me now ... But at least you will know the whole story So maybe you could come up with something

Author:	sports850 [ Mon Oct 12, 2009 1:55 pm ]
Post subject:
Actually when you read a bit deeper into the engine turning around stage of design most of the people involved have admitted it was for the improved gear train in the drop gears as a single drop gear was failing . According to Garfield's book I'm reading at the moment they didn't encounter carb icing up until they turned the engine around .

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Author:	Phat Kat [ Mon Oct 12, 2009 3:41 pm ]
Post subject:
sports850 wrote: Actually when you read a bit deeper into the engine turning around stage of design most of the people involved have admitted it was for the improved gear train in the drop gears as a single drop gear was failing . According to Garfield's book I'm reading at the moment they didn't encounter carb icing up until they turned the engine around . Oh ok,, Cool,,, I just heard what I wrote In the "John Cooper" DVD or "The best of the Origianl Mini" but that could be the case. They do still ice over the way they are (I'm told) in their current position... It just seemed relivant.... Have you read yet that they got better mpg with it the way they had it first? Kinda funny hey So mstmini,,,, How's that prototype coming along?

Author:	Morris 1100 [ Mon Oct 12, 2009 5:58 pm ]
Post subject:
The carby ice story was a deliberate "myth" to hide the gearbox problems that came from using existing gearbox internals with two heavy primary gears acting as extra flywheels. The motoring media knew that the prototypes had the carby at the front and then suddenly they had the carby at the back. The media needed to know why they changed the whole layout so they came up with a cover story! The Austin Maestro/Montego has the carby at the front of the engine bay on an A-series engine.

Author:	Asphalt [ Mon Oct 12, 2009 7:10 pm ]
Post subject:
Mini Mad wrote: There is no need, the air pressure coming in through the front grill forces cool air into the carbs anyway. It comes in through the front and gets forced out the side radiator and down the back of the motor and under the car again. I think the idea is more to have a resonating pressure wave (due to the lenght of the pipe) which sort of acts like a 'charger' (air gets 'rammed' in the intake). And of course, like Phat Kat mentioned, it's not a 'bolt on' thing... Warm air heating up the carb/air 'round the carb is realy only a problem in slow city traffic conditions or standstill. I guess at 20km/h+ it's irrelevant What I'm going to experiment with is a fixed jet for HIF carbs. 'Cause I have a feeling that under said conditions my mixture weakens considerably due to heat rising from the LCB. Cheers, Jan

Author:	drmini in aust [ Mon Oct 12, 2009 7:15 pm ]
Post subject:
Vizard devoted most of a chapter to it and came to the conclusion ram charging is pretty much a waste of time. In an A series with only 2 intake ports.

Author:	TheMiniMan [ Tue Oct 13, 2009 12:32 am ]
Post subject:
"Ramming" air into a carby is never really a "Perfect" thing,,, Carbys find it difficult to "feel" a "denser" mixture & it`s difficult to meter the fuel correctly for any given rev because in first gear you are only travelling fairly slow (compared to top gear) & yet the engine needs to be able to go from low revs , rght through to high revs, with very little ram effect,,,, but then in top gear, you have a fair bit of ram effect & you can still find the need to drive from the same low revs right through to high revs in top gear "With" that ram effect most of the way so,,, how does the carby differenciate (or know) between low "speed" (no or low ram effect) to high speed (high ram effect)???,,, answer is---> it doesn`t do it very well at all well the only way is to "TRY" to have a "Balanced" system--> float bowl also rammed much like a "Blow-through" turbo system & a restriction just prior to the mouth oif tha carb to "Try" to achieve some sort of depression relationship,,, but it`s not a very successfull solution However---> most of the later motorbike carbs have a fairly good "Ram-Air" system but they use some pretty wicked carby designs to achieve it,,, if you chose basically any of those late "Ram-Air" bike carbs then you could do it pretty well these days, but i still think it`s a fair bit of mucking around for very little improvement,,, that is unless you like having fun mucking around trying new things like ram air quad bike carbs on twin cam 16v cyl head conversions but i don`t know who`d want to bother with such rubbish ideas like that tho

Author:	sports850 [ Tue Oct 13, 2009 6:33 am ]
Post subject:
Phat Kat wrote: sports850 wrote: Actually when you read a bit deeper into the engine turning around stage of design most of the people involved have admitted it was for the improved gear train in the drop gears as a single drop gear was failing . According to Garfield's book I'm reading at the moment they didn't encounter carb icing up until they turned the engine around . Oh ok,, Cool,,, I just heard what I wrote In the "John Cooper" DVD or "The best of the Origianl Mini" but that could be the case. They do still ice over the way they are (I'm told) in their current position... It just seemed relivant.... Have you read yet that they got better mpg with it the way they had it first? Kinda funny hey So mstmini,,,, How's that prototype coming along? They had more power as well with the motor around the other way , the extra gear before the gearbox robbed that little bit more which was enlarged as a percentage once the drive had gone through the gearbox .

Author:	sssstew [ Tue Oct 13, 2009 12:57 pm ]
Post subject:
the miglia racers run a custom airbox and pipe which creates a ram air effect i beleive. But then they are running injection rather than carbs, so the above problems mentioned are not relevant if im correct?

Author:	drmini in aust [ Tue Oct 13, 2009 2:53 pm ]
Post subject:
sports850 wrote: Phat Kat wrote: sports850 wrote: Actually when you read a bit deeper into the engine turning around stage of design most of the people involved have admitted it was for the improved gear train in the drop gears as a single drop gear was failing . According to Garfield's book I'm reading at the moment they didn't encounter carb icing up until they turned the engine around . Oh ok,, Cool,,, I just heard what I wrote In the "John Cooper" DVD or "The best of the Origianl Mini" but that could be the case. They do still ice over the way they are (I'm told) in their current position... It just seemed relivant.... Have you read yet that they got better mpg with it the way they had it first? Kinda funny hey So mstmini,,,, How's that prototype coming along? They had more power as well with the motor around the other way , the extra gear before the gearbox robbed that little bit more which was enlarged as a percentage once the drive had gone through the gearbox . One reason for that is the original was a 948, not 848.

Author:	mtsmini [ Wed Oct 14, 2009 6:54 am ]
Post subject:	Ram air system
Already designed a cool air box system: - Two scoops behind grill - Left and right 3" flexible pipes to carbys - Carby box that feeds them cool air (cool air = less volume = more oxgen per unit volume) Post pictures as soon as all constructed. God...I've gotta get a life!

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Author:	Moriarty [ Wed Oct 14, 2009 8:41 am ]
Post subject:
Interesting reading here I can't believe the marketing department lied to us So with the benefit of 50 years - and advancements in engineering and materials - has anyone found a way to improve the gearbox design and rotate the A-series back to its original orientation, in a Mini? Morris 1100 wrote: The carby ice story was a deliberate "myth" to hide the gearbox problems that came from using existing gearbox internals with two heavy primary gears acting as extra flywheels. The motoring media knew that the prototypes had the carby at the front and then suddenly they had the carby at the back. The media needed to know why they changed the whole layout so they came up with a cover story! The Austin Maestro/Montego has the carby at the front of the engine bay on an A-series engine.