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to weber or not?

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rikiwho123

rikiwho123

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getting real tired with these quad carbs not working smooth so i'm asking all for advice on what type of carbs give the best bang for the buck side draft webers or S.U's ; its for a spitfire engine 1300 bored 30 over 4-2-1 headers stage 1 head with 10-1 compression and a mk3 cam .
 
Per Ted S.

The 1 1/2 SU twin setup. Call him, he prolly has a set ready to go.

I have the Weber, it's ok, it's strong point is that it's infinitly variable, and it's weak point is that it's infinitly variable.

One of the problems with it is that way the manifold is setup, the primary feeds cyls 1 and 4 rich while the center two run lean. The twin set solves all that.
 
Just the stock twin 1 1/4 SU's with a little richer needle should be fine, or step up to the UK spec 1 1/2 SU's from the spit or midget 1500. Thats basicly the same setup I'm running and no problems.
 
SU carbs all the way. Easier to tune, great response, not even close to being as fussy. I need to get mine rebuilt, but still they give me 26-28mpg, and I out accelerate the Spits with Webers, except the guy with dual side draft, balanced and ported engine... I run a 4-1 header, have about 8.8 compression ratio from skimming the head, and everything else inside my engine is stock.
 
71MKIV said:
Per Ted S.

The 1 1/2 SU twin setup. Call him, he prolly has a set ready to go.

I have the Weber, it's ok, it's strong point is that it's infinitly variable, and it's weak point is that it's infinitly variable.

One of the problems with it is that way the manifold is setup, the primary feeds cyls 1 and 4 rich while the center two run lean. The twin set solves all that.
Click to expand...

I suspect you don't have a side-draft? One choke per inlet port from a DCOE is exactly the same distribution as for twin SUs.
 
Right, I have a dgv, with the manual choke. The manifold has a plenum just under the carb that's supposed to allow all four cylinders to be equal. But in real life the primary feeds the outside two overrich and the inside a bit leaner.

In my younger days I thought it was better, and I've run it for a long time. I'll go with the twin su's someday when I have enough money to redo the head.
 
Rikiwho123- I say stay with what you have. Your frustration is not unusual with those carbs and the vendor you got them from.
Seems to be the pattern.
I would suggest you contact people who have them installed. I don't think anyone here with a 4 cyl. has them . I know a few with the 6 though.
They can be a great carb when they are dialed in. Unfortunately you're in on the ground floor.Eventually they will be sold pretty close to tuned for the car
 
"quad carbs"? Not sure what setup that is.

DCOE Webers would be expensive and time consuming to dial in but once set up, pretty much rock proof. For the dollar tho, the SU's would be the better answer.
 
DrEntropy said:
"quad carbs"? Not sure what setup that is.
Click to expand...

Doc,

Most likely they are Kehin(sp?) carbs most often used on Motorcycles, ATV's, snowmobiles etc... Could also be Mikuni's.

carbs2.jpg
 
Just did battle with a pair of those "K" thingies (Keihin CV carbs) on a pal's Honda 500 V-twin... depression carbs with <span style="font-style: italic">emulsion tubes</span>. BAH!!! Hybrid SU/Weber nightmares. No thanks. Mebbe for a racing effort but not on any street engine I'd have.

On the English lumps the DCOE's are about as exotic as need be.

Anybody (besides Grantura :wink: ) have occasion to fettle around with the old Lucas sliders? THERE was a bit o' kit. :jester:
 
I have had my duel DGVA's on my TR6 for 4 years now, the only thing Ive ever done to them was on the original setup I rejetted them, then I set them and for get them....Nevr had a problem with them since.


KNOCK WOOD~!

tr18.jpg

HPIM2041.jpg
 
You think 4 are tough, One of our local 6's

SSL23335.jpg
 
hey don i see why you put on those sun glasses on ; sure makes me want to get them set up.
 
you could always go with a megasquirt too. :jester:
 
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