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8 Port Engine For Track Days/sprint Hill Climb


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#1 Curley

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Posted 13 March 2018 - 07:12 PM

I had planned to build a short stroke, blown 1000cc to use in sprint and hill climb series. Classes ran up to 1.4 and over 1.4 with a 1.4x for forced induction. I had planned to use an MED billet 970 crank but in the time it took for me to save for such an £££ item MED stopped selling them :(

 

Truth is I don't have the time to commit to a full on race season, and hill climb looked to be a way to have fun and rag my mini when commitments allowed. I do about 5-6 track days a year in my MINI so I guess it would be nice to have the option to use the Mini for circuit racing too.

 

 

I'm therefore kicking the idea of a EFI 8 port around instead. My question is, to the racers out there, what sort of usable power can I expect from such an engine? What size piston and stroke would work best? Would it be the sort of engine that needs lots of revs and need a 4 bolt main or would it be a low down torque thing?

 

I'm thinking of the Minispares 8 port EFI cam, which is a 310 I believe, on an A+ 1275 block with cylinder liners. I already have the ECU, SC gearbox and want a pre-verto clutch. I'll probably get the crank, rods, pistons & clutch from MED or Swiftune and have them balance the whole assembly for me.

 

Oh and it has to be something fruity!!

 

 

 



#2 nicklouse

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Posted 13 March 2018 - 07:45 PM

What class are you planning on running in?

Have downloaded the blue book regs yet?

Guess you are planning on just doing it for fun rather than winning?

#3 Curley

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Posted 13 March 2018 - 11:24 PM

Funny you say that, this all started because I had an old mini and wanted to have some fun with it. I told myself I just wanted to take part.... that lasted all of about 10 minutes into my first event and I quickly discovered my 1293cc was simply not competitive in an open class upto 1400cc.

 

After completing my National B license, with the help of Ian & Neil Slark we set about modifying the body itself to comply with Mini Miglia regs. The only differences are the bolt on panels, subframes, running gear and suspension are 'open' as I figure its easier to change these back to Miglia spec should that be required.

 

Truth is i'm not that good a driver to win, I need more seat time, so i'll settle with competitive for now. My overriding requirement is to build something you don't see everyday, have fun & enjoy motorsports.

 

What are you running in your car, have you got any experience with the 8 port head?

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#4 nicklouse

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Posted 14 March 2018 - 12:30 AM

Ok I used to run in the BARC class A Mod prod up to 1400cc and looked after a 1380cc 5 port metro that held the Harewood class record for about 12 years it was finally beaten with a 300kg lighter car with a 16v head and a budget greater than the metros for a few years.

I don't believe in power and in hill climbing it is not really something I look for. What you want is torque and good brakes so if you have to slowdown you can do so quickly then add some grip so you don't have to change speed you end up with a car that seems to travel at the same speed up the hill but keeps winning.

I have no idea about the 8 ports as they were not available in the early 90s

Me I ran in the same class with a 1293 engine and picked up a few seconds but spent most of my time help others out in the class.

What I do know is that the power difference with a K head is very little between a 1293 and a 1380 being , according to SC in high numbers below 200. I forget the actual numbers as it was some time ago. So about a 25ish% increase over the 5 port (may be more) the 8 ports are a step between and to me seem to be a why head. Yes it should make more power and torque than the 5 port but is going nowhere against a 16 valver.

But for the cost it will be fun and maybe not quite as highly strung as a 5 port for the same power.

The reason for asking about having read the regs is some people ask about running their road going mini in the road going class but don't realise that the Vauxhall red top puts them in sports libre. Or their Z car Mini is not a Mod prod......

#5 mini13

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Posted 14 March 2018 - 09:10 AM

what valves/porting are in the head? as that kinda dictates cam choice,

 

If I was going this route I would looking at shorter cams, although you can get away with more in an 8 port I'dbe thinking around 290 degrees, also i'd be looking at long induction lengths, ie a big hole int he bonnet...






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