I know of a few that ended up doing speedway in nsw in the mid 60's as they were cheaper to buy than a cooper but could still run with twin carbs . As i said before , there are very few genuine ones left . On the road a twin carb 850 will happily keep up with bigger engine mini's until you get to a big hill (doesn't have that staying power grunt) . It's a lot more responsive than a single carbed one .

_________________

It appears - read appears - , from Peter Manon's letter (posted previous page) that the only performance modification was to go from a single carb to twins (and it retained the cast exhaust manifold?) yet gained substaintial performance gains??? Somehow I doubt it, it must have had more done to it. At the end of the day the single 1 1/4"SU will keep up flow with the standard cylinder head and cam. Putting an extra carb of the same size on wouldn't do much if anything for it's performance. It must have had more done to it (cylinder head, cam???).

My brother had a deluxe to which he did nothing more than put on twin 1 1/4" SUs and Extractors (std cooper) and it felt more torquey, but on a timed 1/8 mile was only very marginally better (about 0.3 sec from memory).

According to Clive Trickey (remember him?)- when BMC put an HS4 and higher compression pistons in the UK 850 automatics, it was worth 4HP at the crank. This made up for the extra power loss in the autobox.
The head was a stock 850/998 though. No 12G295 (they went onto the 1098 automatic only).

So, it doesn't take much work to coax a few more neddies out of an 850.
But I'm with you GT m, I reckon the 850 head must have got a slight tickle... within the standard port and valve specs of course.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

actually no , they used the bottom (exhaust) half of the standard manifold and the standard exhaust (with the bend that is normally in front of the rear subframe removed so the exhaust became a centre exhaust which they called a sports exhaust ) . Ian Anlezarc (Zak with the yellow speedster) was converting 850's into sports850's in his time at P & R William's and remembers them being standard apart from the extra carb . That's not to say the one tested for the magazine report wasn't given an extra bit of attention though A handfull of sports850's were sold with extractors and a twin outlet (like the UK upswept peco unit) muffler , maybe one of these was the test example ?

_________________

It didn't matter how many HP the Sports 850 had. The important thing was the twin carby manifold.
Manton needed the twin carby manifold so he could race a Mini with a twin carb manifold. Under the racing rules of the day he could do a lot of modfications to existing bits but he needed the right existing bits.

BTW, it is very hard to keep the stock exhaust manifold when using twin carbs.

Ta Doc.

Yes, I remember Clive Tricky, first Mini Performance book I read (Tuning the 850 I think) and I've still got that book, though very outdated technology now!!

As far as the sports 850 go, I've seen them but not been in one so I'm not knocking it, it's just that it doesn't quite add up to me.

With the Auto's yeah I know that the Mini's retained the std head but had the HS4, but I seem to recall that they did also have a 'revised' cam (longer exhaust duration, although the factory W/S manual says they were the same).

i should point out too that when describing how mine runs , at that stage it had a standard 202 head and basic 3 into 1 extractors ...

_________________