Just wondering if many have had sucess with using quad carbs off roadbikes on the A series engines. I had a look on youtube and seems to be a lot of VW engines with them. Mates got a set off i think a GSXR1000 or something, was thinking of buying them off him to put on my A12.
My engine for now is standard. but im wondering what kind of gains the quads will yield?
Anybody got dyno result for quads?
Cheers Lads.

anyone?

do a search its been covered plenty

Bike Carbs yeah they don't work very well, but look very cool

There is definitely a gain going for 4 individual carbs that are well tuned with good ignition. I guestimated 15hp over the stock carb and 5hp over twin sus with my old setup but made sure I had more compression also all else close to stock.
You have to make sure the runners are long enough for extra response down low to suit engines that run at halve the revvs from the bikes they came from.
Otherwise extra long velocity stacks also help.

I had them on an A15 courtesy of D and can vouch that they go very well, best thing this side of fuel injection, better really cause there is no computer to dick around with.

They went really well when tuned well (not by me!) but you have to be careful as too rich and you can glaze your bores.
Andy you got the butch "D" tuned ones :( night and day compared to the ones I had setup professionally on the works high comp A16 I gave up on after 2 split bores.
They go hard though, isolating the pulses for each cylinder helps more than I thought it would.

I've had the bike carbs for bit, Keihin FCR flat slides 39mm. On a stock or stockish motor you're not gain to see a great gain, it may even go slower. Before I installed a more aggressive camshaft , the motor was borderline over carbed under camed. With the GX cam it did, as you'll see in the link Dave posted, make 73 RWHP. The addition of the carbs was worth at least 10HP, maybe more. At the track I run the speed at the end of the longest straight was almost 5 mph more. I've yet to dyno the car with the new cam, but it's likely up to about 80RWHP as I've picked up a couple hundred more RPM.

The reason I used bike carbs is due to left hand drive cars requiring moving the brake master cylinder in order to fit webers. I also got the whole set up for less money then the cost of a weber DCOE manifold.

Dave clarify the "don't work well" part of bike carbs.

For me they work great but I only use it on the race track. Also the bike carbs require a little more work as they are less common so not as much knowledge about them floating around. Basically it will require a custom manifold

Tom

yes i should have clarified that. The "don't work well" part is just bolting on bike carbs. Multiple guys found out they run terrible until tuned. Contrast that with your average DCOE or DGV, bolt on and it runs pretty good. Tune it and it runs excellent.

Bike carbs on a car engine often don't work well at first -- but can work well after tuning. You are the only guy I know that tuned his to work great. Others 1200 fans either never get em going great, or pay a tuner to get it done.

Tom, do you think there are any power gains over twin DCOE?