New Project Engine - What route to take?

[Southy]

Right well people I've got a new project coming up with my father sometime soon and we need to sort and engine out for it.

This particular car is a tax exempt one and we are trying to keep it fairly close to original spec as possible but kind of have a sleeper look to it.

The engine is deffinantly going to be a rally/race spec 1380 but I'm unsure as to what head to run on it. I basically have a couple of choice's to go down but not sure what would look and feel the best.

7 Port

This basically is similar to the std spec head but has 7 ports to it. It run's a xflow design and when fitted on a std engine it can see increase's of about 30%. This head can be run on 2 set's of weber's, on throttle bodies or even running on bike carb.s Power can be seen upto about 160bhp if not more.
Running the car on injection means its more driveable down low on the rev range and gets better fuel comsumption. With it being similar to the original head it means less needs to be changed to the engine, same cam, same exhaust manifold etc. There are a couple of these heads on the market, some available in cast iron and some in ally. These range from about £1100 to £1600 for a full race head.

16 Valve Head

Right now this is where things get a little more complicated, you can fit a K1100 head off a BMW motorbike onto a Mini engine with some work. The block needs to be altered and new head bolt holes need drilling/tapping out, jackshaft to drive the oil pump due to the cam no longer being used, and also changing the cam drive system for the head over to belt drive meaning ally welding is needed. I can do most of this work at work, but things start getting expensive with stuff like manifolds as they are custom made.
Again these can be run on ITb's, weber's or bike carb's, power is around the same as the 7 port head 150bhp with a mildly modded head.
The heads cost less around th £400 mark but its all the work which is needed to do the job which takes time, a steel HG is needed costing £100 and also a loom is needed were I to run it on the original carbs which costs around the £400 mark also. So in the end they both work out the same kind of price.

Just wondering if anybody on here has any oppinions on which one you would go for personally?Im swaying towards the 16valver but its a lot of work and a lot of money for the custom parts.

[Jammin]

What are the main differences in performance characteristics between the two mate? What are the powerbands of the two likely to be like, are the RPM limits very different? And whats the reliabilitay front?

Project sounds faffin awesome though

[Southy]

They both have similar kind of characteristics really, as they both flow really well the bottom end will be made to rev so will be capable of upto 8k if not more. The 7 Port powerband will kick in a little higher than the 16v dut to the choice of cam but the 16v will have a lot better low down torque.

Both of the heads do tend to work better when on injection and give better low down power than when ran on the weber's.

On the reliabilty front, the engine is pretty much pushed to its limit anyhow at 1380, the 7 port can use a dry deck system (core plug in the end of the head) which virtually eliminates HG failure due to water not actually flowing through the head itself. The 16v as stated use's a reusable steel HG , and also the waterway has to be positioned as do the oil ways for the new head, this moves them away from the combustion chambers.

[Southy]

Ohh and another thing both of these engines have the possibility of being turbo'd and they put out some meaaaan phowar then Looking around 250bhp mark then if not more depending upon boost. You just need custom parts making up which starts costing £100's

[Jammin]

Aye to be fair on the road Injections the way forward now unless your pockets be lined with gold .

Turbo front sounds good, is there any scope for supercharging?

I reckon you should go for the 16v. I obviously know nothing about this setup other than what youve told me, but if the BMW head gives better torque low down thatll make the car more of a hoot to drive from my perspective. Both will be lairy so youll get to enjoy keeping it up in power, but having it all there and making it a constant challenge might take away from the fun of the beast a little.

It seems the more modern option too, and I reckon deep down youll prefer doing all that work anyway . Plus putting a cylinderhead from a bike on a Mini engine is stupidly cool, and it looks fecking awesome to boot.

[Boostjunkies]

my mate matt has a era kitted mini and is currently running a 1275 on carbs, he's now opted for the metro turbo option, we did speak about the k100 head for that but tbh unless your stuck with regs on cc or racing in a bracket like hill climbing, there are better engines already out there, vetec, xe red top,
bike ect i'm sure you'll come up with something cool though

[Nath]

or a 1.3 turbo(4efte) out the toyota starlet,would save you money if you were to go boosted

there are also 1.5 turbos in the form of (5efte)

but if your wanting to keep the standard mini side of things then maybe thats not for you

[Southy]

I did think about engine conversion but its the hassle of modifying things to fit like the subframes etc to get everything right, where as the above units will just be a case of dropping straight in.
I'm VERY tempted to keep pushing my boss for a free/reduced price 7 port head for my Mini as a demo car for them at shows as we are without since we sold Phil Short's racer, will make it around 160bhp then

[loudandproud205]

16v as the cam covers look so much nicer, why send all tha money if it dont look the tits and still has performance.

plus it looks aero style in a 60's style

[Nath]

And 160 in a mini is more than enough

[DanH]

Any major weight differences between the two? With the mini being as light as it is, I expect even the smallest differences can result in the car being more unseated - although you'd know more about this than me, what with your Mini based experience.

Got a mate who's dropping a B18 VTec in a Mini - should be a beast if he pulls it off I reckon!

[Southy]

Originally Posted by loudandproud205

16v as the cam covers look so much nicer, why send all tha money if it dont look the tits and still has performance.

plus it looks aero style in a 60's style

I must say the cam cover's off that BMW bike head do look the sex

Originally Posted by nathan818

And 160 in a mini is more than enough

Tbh 110 is a bit of a handfull but meh, can never have too much power

Originally Posted by DanH

Any major weight differences between the two? With the mini being as light as it is, I expect even the smallest differences can result in the car being more unseated - although you'd know more about this than me, what with your Mini based experience.

Got a mate who's dropping a B18 VTec in a Mini - should be a beast if he pulls it off I reckon!

Weight wise I'd imagine not a lot really, If anything the 16v one will be slightly heavier due to its larger size with it being wider and slightly taller but not enough to make any majoy difference to the handling.

Well the gearbox will have to be pretty sorted to take that kind of power so I will most likely fit an LSD with it all. Everything on the car will be adjustable also to get the best handling out of it aswell.

Ohh they are a beast indeed, seen a few beat some Scoob's down the 1/4 miles Could if I had silly money make a Mini which would eat 800bhp skylines with ease

[Nath]

you getting straight cut gear's

id go 16v after having a read

[Southy]

Originally Posted by nathan818

you getting straight cut gear's

id go 16v after having a read

Straight cut gears are a must on a Mini after about 110bhp, especially SC drop gears.

Got a SC box on mine but thinking of buying some drops soon.

[Nath]

whats the difference between straight cut and straight cut drops ?

[Southy]

Well on modern cars, the drive from the crankshaft transmits the power directly to the gearbox as its sat on the end of it, with a Mini the gearbox is sat underneath so it needs to transmit that power down thru the gearbox it does this by a set of 3 gears called he drop gears. The drop gears get the most abuse and with helical gears power output of over 110bhp starts putting large side loadings onto the gear and the surrounding casings causing problems, not to mention losing a fair amount of power

[Nath]

Ah I understand that,thanks alot for the explaination. So you need the straight cut drops as there stronger,there for move less under high power loads,also id imagine you lose less power through them

[Southy]

Originally Posted by nathan818

Ah I understand that,thanks alot for the explaination. So you need the straight cut drops as there stronger,there for move less under high power loads,also id imagine you lose less power through them

Technically speaking no they aren't stronger as with std helical gears you have three gear teeth meshed together at once where as with SC gears you only have the one.

They just can take more power than the the std ones as there is less side loading put upon the gear's themselves

[James]

go for the 16v and turbo it dude
something different
and i bet you'll be dead proud when you finally get it done
also, cant complain about lower down torque

quick question, how are you finding your mini's fuel consumption with the carbs you are using? i'm considering getting twin 40's but i'm really not sure

[Southy]

Well a few people now are doing the 16v turbo in the Mini scene now so it's not really something different anymore.

Well I did a nice long run down to Cirencester the other week doing a steady 60-65mph and managed to get 35mpg out of it, but on my normal run's with a bit of a heavy right foot I've seen as low as 22mpg.