Twin S U's on a stock 4K

[MrTimmah]

Hi Guys,

 

I have a 79 KE55 and recently picked up a pair of 1 1/4 su's for it. I have done some digging on this forum and see that unless i  build a "Tough" K motor that they won't be any good with a stock setup? Does that still ring true? 

[rebuilder86]

I'm no expert, but a 1.3 litre designed for less than 80 hp is no place for 2 x 1.25 inch carbies, especially SU.

atomisation of fuel is the problem.

i can't give u any solid figures but i just feel that its going to constantly bog down. ive used a single su and threw it in the bin.

 

but now ive given u the amm9 to prove me wrong, and u have the carbs so make it work

 

[altezzaclub]

I use them, but as typical I've done a porting job, raised the compression, fitted a ground cam & extractors. Definately its faster and uses less fuel, and the SUs are very tuneable.

They come off a 1L Austin Healey Sprite or a 1L Mini Cooper, amongst others.

They won't bog down, you can tune that out of them, but I don't know if they are any better than the Asian. Give it a go and see.

 

[rebuilder86]

there is 2 of them ona 1l engine :o

haha wow. that puts my theory to bed.

Perhaps my experience is with a Junk SU. i couldnt get it (a single downdraft SU) to operate efficiently, or even close to effectively.

interested to see how it goes and i hope u can learn enough about it urself to tune it good.