k1200 head: worth the hassle?
Turbo Mini Forums

A question to those who've been there and done it: is fitting one of these worth all the trouble, compared to just sticking to a 5 port head? Just wondering since I've found a K1200RS head locally (albeit way overpriced at 500 euros). I still haven't completely decided which way to go, but the base will be the (ex-Prawn) Mpi block with the 18cc accralites and a GT1752. The way I see it getting the 5 porter on injection is going to be a pain, but fitting a K head is not easy either (but looks wicked :)
Having also seen that a K head only has a chamber volume of about 18cc will I be able to get the CR low enough to fit a turbo, even with 18cc pistons, or should I forget about that altogether?

thanks

1963 Cooper
1975 Pick Up

All i can say is that a 5 porter turbo is fun enough for me.

Enginering wise it's a challenge to get the k-head working......

there is nothing wrong with a A-series that a turbo can't fix.

www.turbomini.nl

Personally the extra control the 16v head provides is undeniable. Yes this control can be had from a 5 port with siamese port injection for example. However its a bit of a faff really given no parts are "off the shelf"

Ultimately the cost involved with either solotion would be considerable. Im temped to say a bmw conversion would prove to be more economic. Given that unless you can modify your own cylinder heads this is a cost to factor.

Also with the twin cam design you can alter the LSA of the camshafts, another merit for the twin cam.

the 2 main reasons amoungst others for me are.

1. Better heat dissapation as I intend to do circuit work
2. top end power without having to use massive cams killing the bottom end - think 8k plus.

Edited by minimole23 on 24th May, 2011.

Mine is great fun, drives completely different to a 5 port. It is alot of work, more than just bolting on a conversion kit, especially if you go down the turbo route. But if you enjoy a challenge, then it will certainly give you one!

I recently drove mine to Newquay and back, and it happily cruised at 5k all the way down there. The scarey thing is, it doesn't sound like its revving its nuts off at 5k where a 5 port would.

CR isn't a problem really, don't forget you can use a higher CR with the K head because of its design. Im running around 9:1 and it'll run 25psi even on 95RON fuel. :)

Edited by matty on 24th May, 2011.

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1/4mile in 13.2sec @ 111 terminal on 15psi

Jack Jones

thanks for the replies sofar guys :)

1963 Cooper
1975 Pick Up

Once the engineering bit is done, its just like any other engine to build and rebuild. and once you sort the packaging into the car out, you'll reap the benefits later. I don't think any one will tell you its easy, but its only hard at first, like most things.

And it has been done some times already; a lot of lessons have already been learnt..

Here is one build thread of philc:


There are some more build threads to search for..

Dazed and Confused....

Are you aware of the EFI mini`s website? chuck edi minis into google should bring it up.

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1/4mile in 13.2sec @ 111 terminal on 15psi

Edited by minimole23 on 25th May, 2011.

I generally stick to V power, and thats what I mapped it on, but on long runs it gets kind of expensive!

Ive noticed it will knock slightly on light accleration on the lower RON fuels, nothing that couldn't be corrected with a bit more fuel in the map. But to be honest with my driving style its all or nothing.

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1/4mile in 13.2sec @ 111 terminal on 15psi

I've gotten the bug I guess. That is to say I picked up a K1200RS/GT head tonight. Initially the seller wanted 500 euros, but when I explained what the plan was he got so enthousiastic I could pick it up for 175 (albeit without cam cover or TB's, but I'll worry about those later). It came off a police bike that threw a rod at 27k miles, but appears to be undamaged.

Edited by Arnoud on 25th May, 2011.

1963 Cooper
1975 Pick Up

Matty we need to get together some time and seriously upgrade the firmware and software for your ECU. Many many excellent changes available

Let me get it sorted on mine forst though

I have updated it to the 93 version, is there another new one available? lol

I still haven't managed to get the vemstune working though, which is annoying.

I need you to come and have a look, and wave a magic wand to get my oil leak fixed before Avon. :)

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1/4mile in 13.2sec @ 111 terminal on 15psi

On 25th May, 2011 Sprocket said:

Get the cam cover if you can, unless its damaged, they are not freely available second hand, and cost about £120 new

1963 Cooper
1975 Pick Up

cover gasket costs naff all, certainly not 50 euros

When you add the cost of cam cover bolts and seals it soon adds up though!

Arnoud - check out this site for spares to give you an idea of cost! 110EUR may not be too bad. http://www.motorworks.co.uk/vlive/Home/index.php

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1/4mile in 13.2sec @ 111 terminal on 15psi

trouble is its the cab covers that get it if the bike is dropped.

Thread hijack

On 25th May, 2011 matty said:
I have updated it to the 93 version, is there another new one available? lol

I still haven't managed to get the vemstune working though, which is annoying.

I need you to come and have a look, and wave a magic wand to get my oil leak fixed before Avon. :)

On 25th May, 2011 Sprocket said:

Thread hijack

1963 Cooper
1975 Pick Up

i have to agree with what has been said, the build especially if you do it yourself is hard work and can be time consuming. i have made a few mistakes, but this is how you learn. glad to see you have gone with the bmw conversion, i am confident that you will not be disappointed.

On 27th May, 2011 philc said:
i am confident that you will not be disappointed.

1963 Cooper
1975 Pick Up