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When BMC came with the split webers for the 1968 Monte Carlo, they had to keep the SU inlet manifold to stay in gr.2.
Was the inlet manifold later free and from what year?

Did Richard Longman sell a split weber set and from what year?

Pretty sure it was free in Gp2 by 1975 and pretty sure it wasn't in 1973 (when I used a Cooper S in Gp2 on SUs and a 45DCOE made it Gp6 - if Gp6 was allowed in the event). Unfortunately the FIA web site does not list every year in it's historical Appendix J data, so neither memory nor data allows me to say it was 74 or 75.
Bizarrely, the significant changes to Gp2 for 76 (that are revealing so much ignorance in the MSA/BHRC) did not affect inlet manifold.

IIrc, Makinnen came up with the split Weber idea. It was to fit 45 Weber to a rally mini under the regulations. The Longman concept was slightly different as there were no manifold restrictions in his class of racing. It was more getting a slightly better inlet tract.

Longman split Webers were certainly available from 1970. Here is a piece of blastphamy, I know someone who threw away his 8 port head and bought a Longman 5 port and found about 5 seconds a lap. You wouldn't ever find him buying another 8 port. He was not alone in doing this btw.

ivor badger wrote: Longman split Webers were certainly available from 1970. Here is a piece of blastphamy, I know someone who threw away his 8 port head and bought a Longman 5 port and found about 5 seconds a lap. You wouldn't ever find him buying another 8 port. He was not alone in doing this btw.

ive never seen anyone get the sort of power out of a five port that can be got from an eight port - no matter what carbs are used!

the biggest advantage of split webers over a single is the big 'squirt' of fuel that can be provided low down, when, for example going round a corner in a lower gear

guru_1071 wrote:

ive never seen anyone get the sort of power out of a five port that can be got from an eight port - no matter what carbs are used!

that must be because you have never seen enough people with a good 5 porter.

ivor badger wrote:

guru_1071 wrote:

ive never seen anyone get the sort of power out of a five port that can be got from an eight port - no matter what carbs are used!

that must be because you have never seen enough people with a good 5 porter.

show me a normally aspirated five porter running pump fuel that makes 160 bhp in any combination of carb'd, injected, dizzyd or mapped and i will agree with you........

there must be a reason that all the people i know who race have moved onto 7, 8, 16 valvers if the regs allow it....

guru_1071 wrote:

ivor badger wrote:

guru_1071 wrote:

ive never seen anyone get the sort of power out of a five port that can be got from an eight port - no matter what carbs are used!

that must be because you have never seen enough people with a good 5 porter.

show me a normally aspirated five porter running pump fuel that makes 160 bhp in any combination of carb'd, injected, dizzyd or mapped and i will agree with you........

there must be a reason that all the people i know who race have moved onto 7, 8, 16 valvers if the regs allow it....

Well the reality is that he threw the 8 porter away after I passed him no bother at all using a pair of SUs. I hear all these stories about what an 8 porter can do on a dyno. Unfortunately, races are run on tarmac and I have only seen a few good 8 porters there. The best 8 porter engine in a mini? A Cosworth BDA,SCA or MAE.

ivor badger wrote: Well the reality is that he threw the 8 porter away after I passed him no bother at all using a pair of SUs. I hear all these stories about what an 8 porter can do on a dyno. Unfortunately, races are run on tarmac and I have only seen a few good 8 porters there. The best 8 porter engine in a mini? A Cosworth BDA,SCA or MAE.

but surly you are basing your opinion on one single guy using one single engine and having a poor result with it?

both mike youles and harvey death - who both went from 1460 five ports to a 1460 8 port, and a 1460 7 port found more power and higher grid postions as a result in the HGTCC series?

this is wandering away from the op's question on splits, so, a mate of mine went from a single 45 to splits on his rally car (and had to go from s.ireland to peter baldwin to get it correctly set up!) and found a lot more mid range power at exactly the point he needed it - he reports that it turned the car from a 9/10ths drivable car to 10/10ths

mind you, he also went down the 16 valve route for more power on his hillclimber.........

There's no way a N/A 5 porter can flow better or develop more bhp than a 8port! sounds like long man could sell sand to the Arabs!

I reckon that the point that's being missed her is that Ivor is talking about 8 port tuning in the early 1970's where as guru is talking about 8 port tuning in the year 2011.

There has been a fantastic amount of development over the last 40 or so years.

Back in the early 70's 5 port heads had been very highly developed over 10 years or so in top line motorsport. At this time the 8 porter was a comparitivley new development & to a great extent was not well understood by most tuners.

So, buying an 8 port engine in 1970 could very easily mean that you spent a lot of money on something that didn't work as well as a very well developed 5 porter.

The boot is on the other foot nowadays. With people prepared to pay VAST sums of money for A series engines of either type, development has once again moved on. A 5 porter in the year 2011 makes more power than a similar 5 port of 1970, but an 8 port of 2011 makes vastly more power than either an 8 port from 1970 or for that matter a 5 port of the year 2011.

Its simply a case of PROGRESS.

I know of modern 8 port engines that are producing getting on for 180bhp using fancy cams, modern fuel injection & exhaust systems that look like a plumbers nightmare, this is simply impossible from a 5 port engine regardless of who builds it or how careful it is put together.

So in my opinion, you are both right & you are also both wrong.

Discuss.

Tweet tweet! On the fence! diplomatic as ever mark! I do agree with what your saying though and your right about the era difference.. I suppose the original arden was developed for a small bore say 1litre for arguments sake and if there was a 1275 S with a well worked head then there's going to be a difference.. Saying that if these heads were shoved on big bore maybe they wouldn't perform that great? I dunno
I for one wouldn't go back to a 5porter now though then again nor would I be satisfied with a standard cooper s.. But some people think cooper s's are 120bhp as standard! Haha especially if its been down to peter balwins.

999 ORX wrote:Tweet tweet! On the fence! diplomatic as ever mark! I do agree with what your saying though and your right about the era difference.. I suppose the original arden was developed for a small bore say 1litre for arguments sake and if there was a 1275 S with a well worked head then there's going to be a difference.. Saying that if these heads were shoved on big bore maybe they wouldn't perform that great? I dunno
I for one wouldn't go back to a 5porter now though then again nor would I be satisfied with a standard cooper s.. But some people think cooper s's are 120bhp as standard! Haha especially if its been down to peter balwins.

The Arden alloy head was developed by Jim Whitehouse for Steve Neale, who paid for it himself btw. Steve ran a 1275. SN made his name and Arden's by beating the works cars at the Silverstone F1GP meeting in 69.

Now all this extra power that 8 porters have found through fuels and ignition systems. Can these not be fitted to 5 porters? No reason why not.

Basically power = gas flow in and gas flow out of the head and that does not change that much over the years, the rpms remaining the same. Since the prm is crank/piston speed limited that will not change much, regardless of the passage of time.
Around 1970, if you wanted lots of power, you simply put your car on Aldon's rolling road. David Wizard reckoned to get 75 bhp at the wheels from a std 1300 by use of much tweaking of ignition and mixture,oh and a can of STP.

Tweet tweet! On the fence!, diplomatic as ever mark!

CRAP! I'm not on the fence at all.

I totally accept & agree that an 8 porter was not that much of an improvement over a 5 porter in 1970 & I clearly explained my reasons why I believe this was the case. It is recorded that 5 port Minis could invariable whop the arse of most 8 port Minis during the early 70's this cannot be denied, the results are there recorded for anyone who is interested to see for themselves.

However, over the last 5 years or so, I have seen enough power curves and dyno results from both types of engine to be pretty certain of my view that nowadays if you have enough money, & pay the right person to do the work, you could have an 8 port engine built that would make a well developed 5 porter of similar capacity look LAME by comparison. This by no means excludes the possibility that an 8 port engine built today by "the wrong" person could be just as much of a disappointment as its 40+ year old brethren.

I have NEVER seen a conventional 5 porter give 150bhp let alone 180bhp plus which I certainly have on an 8 porter. These are comparative figures, I am NOT talking about using a high reading dyno like Peter Baldwin's & comparing it to a truer reading one like Mick Barret's.

Is that clear enough!

it siamese ports where any good they would still be used today,

this has allwase been an old boy theory

as has allready been said a few times in various posts the reason the 5 porters where quicker is it had a head start in devlopment. nowdays an 8 porter will allwase be more flexable low down and produce more peak power.

I say all the wrong things! I'm keeping it zipped from now on!

Yeah but, wot about a 7 porter.......

So going back to the split webers.......

Maybe the last cat fight should be put under a new heading...suggestions for the thread title please...."Do three extra ports and several thousand pound's make that much difference"

Just my 2 p worth, my 7 port transformed the car TBH. Even with the same cam, CR and ignition it provided near on 29 hp more than the very good, cleaned up torquey 5 port "S" head. It came on cam sooner, produced more torque than the front tires could handle, very smooth with it and embarressed many a "Sports car" on a recent track day.

Shame you cant really use them in historic rallying for some reason

Split webers.....

Just before we finish on 8 ports it's also rarely mentioned that they can purr like a kitten at idle compared to a popping, kangarooing five port which is a huge plus for road car tuners.

mk1 wrote:...if you have enough money, & pay the right person to do the work, you could have an 8 port engine built that would make a well developed 5 porter of similar capacity look LAME by comparison.

In your opinion Mark, who would you recommend to build a 'good' 8 port engine...?

OK, can a FIA appendix K Mini, race in the pre-72 class, with split weber(free inlet manifold) or with single weber DCOE ?