Hi all,

Engine specs...

5K 40over

9.7:1 compression

Extractors with 1.75" exhaust

Carbs twin Aisan 3KB type

question about cam selection....

Since I want to use these carbs to keep a factory look am I right in saying as these are not big carbs they will limit the maximum amount of air I can get through the engine hence a very high reving engine wont be my best bet 7000 plus.

So since they are smaller carbs they will have a high velocity of air movement and thus effecting the cam selection, with high velocity carbs too much overlap is not good? especially if not using high revs due to the smaller carbs?

I have a Adv 261deg .417" lift at the moment but it has been suggested to go as big as 284deg .465" lift

 

Ideas, suggestions? In summary i'm after the best cam for the Aisan twin carbs.

I ran twin aisans with my setup but only made good power to 7500 and that was with the main jets removed! id go around 280, 290 and 550 600 lift ,

should be good to seven if youve got a bigport on it.....

Wade 169, 3kb manifold, 2 x standard carbs (bigger venturies) would go wind off the tachometer.

Can anything be done about the manifold and the sharp corners the air goes around??

 

Were those aftermarket larger venturis Coln? Cna the stock ones be filed larger?

 

I suppose twin carbs would feed 2.4L at the same performance level as a stock 1.2L single-carb, so they should wind 1.5L right off the tacho....

Can anything be done about the manifold and the sharp corners the air goes around??

 

Were those aftermarket larger venturis Coln? Cna the stock ones be filed larger?

 

I suppose twin carbs would feed 2.4L at the same performance level as a stock 1.2L single-carb, so they should wind 1.5L right off the tacho....

 

Single carbs had a larger venturies and bigger jets than the proper 3kb carbs.

I think the Camtech CT003 517 might be the go... 272deg .442" its a bit bigger than the 261deg .417" I have at home which I think may be a bit small. I will have it Dyno tuned once its up and running either way.

Can someone recommend a good carb guy in Melbourne with a Dyno?

Got a smartphone? Richo d'loaded some dyno app for a couple of bucks and it is most impressive. Then all you need is a flat bit of road you can do 0-110 times on.

 

Start a new topic to see which apps guys are using, or I can ask him which one he got if you want. We're going to compare his 345K with stock and modded KE70s next time I go up.

 

I assume the cam will run on the stock pin, so it can't be adjusted, and you can play with jets in the carb and ignition timing.

Yeah, if can find out what the app is that would be great! I'm now getting sick of looking at cams, but have learnt a lot. 272deg .442" seems like a happy medium, fingers crossed.

I was thinking about getting a adjustable cam gear, but to be honest its just a 5K with twins and exhaust so wont get too carried away, save that for the next build!