Engine: 2.1 Carb B21A: Twin carbs

[foggyjames]

Bit late to the party here...

As Dai says, my 360 measured 140bhp and 145lbft (calculated fly figures) on a dyno with just a pair of 40s and a K cam. The B21 ought to make a bit more anyway, plus a performance exhaust would free up quite a bit. That engine is now in my 1981 343.

The tuning is less than ideal...but that is in the progression stage. It needs different emulsion tubes...or the existing ones altering. It's not bad enough that I've bothered to pursue it in 4 years, though. Once you've got the revs up a bit, wide open throttle is tuned pretty accurately...so that peak horsepower figure is reasonably good for that setup. Bear in mind the standard exhaust is not exactly a performance item. That and some headwork would see 170-180bhp I reckon...oh...and probably some larger chokes for the carbs...the original R-Sport spec was for 32mm chokes!

Don't discount the Solexs. Webers and Dellortos are heavily scene taxed, and I haven't suffered for having the Solexs.

Economy was circa 25mpg at 70mph...not *that* bad. It's very civilised to drive, actually.

And it's worth every penny for the noise...
http://www.youtube.com/watch?v=LLFttupRXJM

cheers

James

[Clan]

It sounds wonderful , did you manage to tune the ignition advance curve to suit and give it a lot ( possibly 40 + degrees ) of advance on light throttle cruising to improve economy? This also has the effect of quieting the engine induction noise when you are gently cruising ...
The 360 carb engine has a very high final drive ratio too which does no favours for performance , ( changing up to 5th at 110 mph in the standard model is satisfying though) fitting a 360 GLT gearbox would make the car feel even more lively ...

32 mm chokes? you'd need a lot bigger for the best output i would say , i think people use weber 48 DCOE's on these engines , i use 32 mm chokes in my twin Dellortos on my 998 cc Hillman Imp engine :-)

[foggyjames]

Ignition is the original Renix unit...at present. Longer term I have a B23E mechanical dizzy (weighted for the K cam) and an MSD setup to give it some power. I might, alternatively, run a MegaJolt setup (ignition-only Megasquirt) to give me programmability.

The tall final drive is excellent for high-speed crusing (more than 100mph is pretty painful in a GLT), and makes it quieter on the motorway...but it's not ideal for accelleration. When I swapped the engine into my 343, I swapped the diff for a 3.82:1 unit from a 340 1.4 5 speed. It's quite a nice match, but a bit 'buzzy' on the motorway. I'll be putting the original 3.36:1 diff back into the 360 when I put the turbo engine in...at which point I'll have so much torque that it won't really matter. To be honest, I've always felt the 3.64:1 injection diff was in no-man's land. It's too short to make for refined motorway use, and the 3.82 is better for accelleration...and not notably worse on the motorway.

I agree that the chokes would probably be better off being larger...but I've been surprised by how well behaved it is, and how much peak power it makes (given everything else). I know of some people who use 45s with bigger chokes, but they don't make much more power. I'm probably going to give 34mm chokes a try...see what effect they have. Given my experiences with the 40s / 32mm chokes on a 2.0 (usually specced for 1.3s, or so), I'm tempted to say that the "textbooks" on the subject are getting a bit carried away with the sizes. What I've got should be far too small according to the wise old owls...but it actually seems to work very nicely. Having said that, I do wonder what I'd make with a set of 45s with 38mm chokes!

cheers

James

[Clan]

It all makes sense really , My 360 GLT was always revvy due to the low final drive but it didnt have the pull you would expect from this , probably due to the hugely heavy flywheel which took 5 seconds to get from idle to 6500 rpm ... with no load !
It is best to change up to second as soon as the car is moving rather than wait in first gear whilst the flywheel accelerates , the higher the gear you are in the less the mass of the flywheel is noticed .

The smaller 32mm chokes will make the engine nice and drivable at low rpm and as the 360 engine doesnt really do high rpm, might be a good choice after all . My 998 cc engine revs to 8000+ rpm and really does need 32 mm chokes ...

I think when you go with your own mapped ignition you will really make a difference in low rpm torque , drivability and smoothness . and economy too of course .
I use emerald K3 fuel/ignition managment on one of my little engines , and building a megasquirt using FORD EDIS ignition for another ...
Keep us updated ! May your propshaft coupling cope :-) one answer to that is to use an Alfa 75 V6 transaxle ...It has the clutch and flywheel at the rear as part of the gearbox .