7 port turbo
Turbo Mini Forums

Yep exactly what I ment

First time I've seen much on these 7 Port heads

Looks good I'll look into it when I'm a bit further with my project

Hi all

Just a few comments about arden 8 port head that may or may not help :)

The 8 port cam is a billet item and costs ?200

The manifold is available from maniflow for around ?250

I wouldn't say the 8 port heads are experimental IMO as they were homologated for rallying in the 60's. More I'd say uncommon, probably due to the cost.

In terms of flow, I couldn't quote figures but I believe my standard out of the box 8 port head flows better than an out of the box 5 port head. Couldn't comment on in the 7 port as I have no experience of that.

The standard head seems to cope with a 296 cam OK at idle (smooth at 1000rpm) and under acceleration. Part throttle is lumpy but I think that is a problem with the carbs.

Looked at the turbo option and as you all have already mentioned CR is the big stumbling block. Talking to DC/Jukka this can be overcome, but injection and full engine management is required.

At the RR day at MBE my car (1380cc, 296 cam, unmodified 8 port head, twin 40's, sc gears) produced 80 bhp at the wheels. I have no idea what torque it produces, but would love to know cost it pulls like a train.

Cheers

Neil

I was wondering when you might give us some advice.

By experimental I ment for turbo use, for NA use I agree that they are a great advantage (if a bit expensive.) But if you wanted a cam to suit a turbo you would have to specify the profile, and the exhaust manifold would also need to be bespoke. I think that would be more than ?200 and ?250 and certinaly not off the shelf.

Don't get me wrong though if someone out there has the money and time to get it working I would love to see it.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Cam wouldn't have to be experimental at all... Afterall, the 8 port then becomes a crossflow forced induction - and there is a wealth of cam information about similar 8v layouts - especially the Renault 5 both in maxi and later 'road' versions...

I reckon that (to do it properly, with EFI and the works) just the externals will cost around ?1500 minimum (special ex. manifold, inlet plenum, ecu, injectors, sensors, wiring, turbocharger, etc) and the internals is whatever they will cost! Even that is second hand parts in some cases (injectors for example).

As with you Ben (and many others!), i'm waiting for the day when someone does build one properly!

even if it did, you could go mapable injection etc, surely these benifits would outweigh any disadvantage?

in reply to a much erlyr post regarding the "flow" of the heads.

Edited by evolotion on 1st Jul, 2004.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I've read that 8 and or 7 port heads need differnet profile cams from a 5 port
Can anybody explain to me why?

The engine still needs to breath in and out in the same way
The gasses just happens to get in and out via different routes

Am I missing somthing??????

yeah...

different head effectivly means a different engine!!!

Alex

AlexF

Don't know about the 7 port, but the valves in the arden 8 port head on cylinders 2 and 3 are swapped, hence the need for a special cam.

I reckon 8portchris and his brother have the best start on an 8 port turbo. They have experience of turbo'd mini's, injection on 8 ports, and modified 8 port heads.

There's doo-ings afoot but it's not my place to give anything away....

Edit to add - does anyone know anything about the Steve Harris (Cranbourne?) 998cc 8 port turbo?

Edited by Neil8p on 1st Jul, 2004.

I contacted them ( Harris ) about their 8 porter, asked them how suitable the head was, if they had any problems with it etc.
All i got back was......... I have been very pleased with my project but I am afraid this item is not for marketing.

Helpful eh !

Chris

Steve Harris Wound the boost out so far in the first run on the RR on my brothers car he blew the engine first go!!!

Not very helpful at all

Are the 7 Port heads valves in the same configuration as a 5 Port?

8-port head have different valve configuration compared to 5-port/7-port heads. 8-port head has in-ex/in-ex/in-ex/in-ex (or vice versa) whereas 5-port cams are ex-in/in-ex/ex-in/in-ex.

Physically they fit but would be interesting to check how it would run ... if all ! Most cam profiles are ancient, don?t know about Minispares range but the cams need to be done out of billet since there are no cores available for regrind.

Depending on the valve layout (crossflow head vs. 5-port like Mini) the engine requires different cam spec simply because of the head?s breathing abilitity (well it?s not that simple because there are also CR, squish, piston dish/dome etc to consider). Things like lift, duration, LCA = angle between the lobes. Often poor exhaust port flow is compensated with longer ex duration. But like Soton wrote any cam will run provided the valve layout matches the cam. It is a question of optimising the cam to the engine requirements.

There are basically 2 types of 7-port heads: AKM that has cross flow arrangement with 4 intake ports at front and 3 at the back. Then there is the Manx racing type that is mini style head with intake ports divided into to narrow ports. This way the charge robbing is eliminated.

I have a BMW 16V head that will eventually end up on top of Mini block. I have so far spent 300 quid for the head and parts and I plan make it run for less than 600 quid. It only takes too much time...

Jukka thanks for info

think I've got it now

7 port heads sound easyer then the 8 port for turboing
more choice of cams etc

Still like the idea of and 8 porter though
will do more research when I've finished my shell and am ready for the engine

in the first keeping your mini alive magazine, there was an article by vizard about the 7 port head from akm, apparntly even with standard port shape it will flow a hell of a lot better than a 5 port head.
DAN :)

Ben H's link above has got an artical by Vizard
possibly same one

yeah that's the article.
its quite interesting to read