Carb Balancing tools. What's the best?

[terryp]

I bought one of these a while back for about ?30

Terry

How do they read the vacuum? Is it necessary to drill and tap the intake runners to insert nipples?

Art
My Dellortos have a screw plug that once removed you can screw the tubes of the gauge in.
I'm not sure that all Dellortos have them

Terry

[frearther]

[/quote]

Art
My Dellortos have a screw plug that once removed you can screw the tubes of the gauge in.
I'm not sure that all Dellortos have them

Terry[/quote]


I was afraid of that. There isn't anything comparable on the Webers, AFAIK. I'd LOVE to be wrong about this.

[ianf]

I'm with Paddy & co and use the Synchrometer - seems to work well with a nicely damped reading. It is quite popular among my friends as well - so it must work.

Ian

[alexblack13]

Ordered the synchro type off ebay. 5 quid cheaper than demon twks. Now to buy colourtune locally.

...Heh!... Thanks guys..

Alex B....

[bill308]

You guys have covered a lot of ground in this thread. Air flow is a subject that is near and dear to me. I recently purchased a Superflow, flow bench to take a look at the Twin Cam and other cylinder heads.

As far a synchronization tools for tuning, and I've used nearlly all of them over the years, I've developed a pecking order of desireablility if you will.

In order of my preference:

Bank of mercury manometers - Advantage; Accuracy, the height of the mercury colume defines a pressure or vacuum. Multiple columnes work perfectly for comparing one cylinder to its brothers, simulltaneous monitoring if you will. The eye can easily detect differences between cylinder heights of mercury when they are parallel and registered columnes, placed next to each other. This is partuclarly avantageous when looking at off-idle transition (acceleration from idle to maybe 2000 rpm). This method accounts for leakage by measuring intake manifold vacuum. Disadvantage; bulky, useses a hazardous substance (mercury). Columns must be positioned near verticle. Doesn't read in true air flow, thus no true mass flow per unit time metric This is the system I use for balancing purposes. It's the best.

Same as above but measurement system with dial gages - Advantage; allows simultaneous monitering of all cylinders. Compact and mountable in various attitudes. Disadvantages; It's a little harder for the eye to compare multiple dial readings verses multiple column heights. Still, it allows some comparison of flows during periods of transition (light acceleration of the engine). Balance accuracy depends on all gages reading the same for a given pressure or vacuum.

Synchrometer - Advantage; Gives a true air mass flow reading. It's easy to use, measures the amount of air passing through it. Disadvantage; must be moved from cylinder to cylinder. Disadvantages; Must be held in place. Measures air flow in only one cylinder at a time. If engine speed changes between cylinder swaps, airflow readings will be affected accordingly. Not useful for looking at off-idle (or dynamic) or dynamic synchronizatation.

Unisynch - Advantage; Inexpensive. Gives a reasonably accurate relative measurement of air flow through itself. Disadvantage; Orientation, the Unisynch must be aligned so that the measurement column is verticle. It must be moved from cylinder to cylinder and each time oriented so that the measurement column is verticle. If engine speed changes between cylinder swaps, airflow readings will be affected accordingly.

hiss-of-the-hose - Advantage; Inexpensive. The tube amplifies the induction pulse (hiss if one carb feeding two or moere cylinders). If the induction pulses have the same amplitude or loudness, air flow is equivalent. Disadvantage; Subjective. The end of the hose and its orientation needs to be placed uniformly when move from one carb-opening to another carb-opening. Transient measurements are not possible.

I hope this helps.

Bill

[tdafforn]

Hi all,
best setup I have found is the morgan quad manometer setup combined with a WB02..
Used to be a big colourtune fan (had four of them, one for each cylinder..)
Then ran the WBO2 (I use the http://wbo2.com/2j/default.htm) .. Even when I had 4 "lovely bunsen blue flames" n the colour tune W02 was indicating 1:20 ratio (way weak)..
Retuned with the WB02 to near 1:12 and whole thing ran lovely (flames yellow)..
Moral: if you are going to use the colourtune, tune to near yellow..
Cheers
Tim
PS also second ed's suggestion that you seek Keith Francks (can be found at sidedraft central)

[bill308]

Tim,

Excellent observation correlating Colortune burn color and driveability.

I've used the Colortune to adjust the idle and off idle mixtures on my Weber dcoe 40-18's fitted to my 66 Elan which ran great. I think at the time I used the Colortune. The fuel blends were different than they are today though.

Most recently, I tried to use up to 4-Colortunes simultaneously to dial in the idle and off idle mixtures for my Ferrari 308 which is a very close to 2-twincams in a v8 configuration. Bore, stroke, 2V hemi heads, carburation, pretty much the same. On the 308, the engine is oriented east-west, a sidewinder. The rear bank was pretty accessable, so I was able to run Colortunes in the 4-cylinders. The front bank was near impossible to dial in with the Colortunes. Clearance was an issue and getting a good view of the window (viewing ring) was near impossible even with a mirror. I also found that insufficient air flow to a particular cylinder would cause a misfire. If I recall correctly, the burn color was an almost white and of a short duration erratic color. To this day, I know the mixtures are less than optimum. What I also discovered is that the burn color really needs to be in the orange for reliable ignition, especially in the idle and off idle modes, the only cases where the Colortune should be used. They (the Colortune folks) caution against use under load. I also feel Colortunes have a tendency to misfire over time. This may be a cleaning issue.

The biggest strengh of the Colortune is that it looks at the mixture of individual cylinders under idle and off idle conditions. Personally, the next time I go through this process, I'll tune to the blue orange boundary, and then adjust a flat or 3 richer. I'll set this with a very hot engine. If it appears to load up or run too rich, I'll tune to the the blue/orange boundary plus maybe only 2-flats richer. Data points form other tuners welcomed.

The final piece of the tunning challange is to optimze mixtures over the road. For this purpose, an Inovate LM-1 is probably the way to go at this time. The follow on LM-2 instrument seems to have severe rpm recording problems. To my mind, this appears to be an inability to cleanly record an rpm signal and translate it into a useable data point(s). The main purpose of the LM-1(2) is to correlate air/fuel ratio (A/F) with rpm. If it can do this, it can correlate A/F with rpm and load. Depending on where you locate the wide band O2 sensor, the sensor will give an average A/F reading at that point. Idealy I'd like a sensor in each of the primay exhaust tubes but will likely settle for an averaged reading at the collector or tail pipe.

I think we're fortunate to live in a age where some of the tools of OEM technology are becoming available to the back yard tuner. These tools take a lot of the guess work out of the process.

Bill

[tdafforn]

Agree about using the colour tune for comparing cylinders (something a single WB02 cannot do)..
(mind you I know people with WB02 sensor ports on each exhaust runner!)
A comment about the RPM reading on the innovate.
The WB02 I use picks up the RPM fine, and I also use a throttle position sensor on my dellortos so I get 3 streams of data.
That way I can look at mixture versus throttle position as well..
Cheers
Tim

[alexblack13]

I am working with the tools that god gave me. Ears and eyes. Sometimes seat of the pants!!

Should I buy two colour tunes. 2 = for each carb at a time. 1 for each eye.

3 parrots were going to work on their perches via a 3 slide system with auto non return doors at the bottom of the very fast slides. Nos 1 & 2 made it and were 'perched' awaiting no 3 who discovered a fault on his slide door. I.E. It was stuck shut. This killed the poor bugger stone dead. later some of his mates were asking what happened to which the witnesses replied.......


.............................. His Parrot chute didn't open!!

Sorry !!! ...


Alex B....

[Spyder fan]

I thought that I was past all this balancing nonsense with Jenvey throttle bodies fitted, until I realised that they still need balancing as there is a connection between the 2 pairs as per DCOE's.....doh!
Good job I kept my Synchrometer, works perfectly and allows me one of the great Lotus pleasure's which is to have a fiddle under the bonnet with the engine running and the airbox off, lovely noise when you blip the throttle.

[moonlander]

Hi All

I bought a Carbtune II off Ebay to tune my Dellortos, they are normally used for bike carbs but they work a treat with the Twin Cam. They came with 4 brass adaptors that screw into the top of the Dellortos so I can check all the carbs together. http://www.carbtune.com/
I then got a bit carried away.........and bought a Suntune Micro 1 for fifty quid, so with a pair of Colortunes I have never had the engine running so well.

[john.p.clegg]

Nobody has yet mentioned the IR thermometer which I find handy pointed at each exhaust pipe in turn for exhaust gas temperature at idle (and above)...

John

[frearther]

Nobody has yet mentioned the IR thermometer which I find handy pointed at each exhaust pipe in turn for exhaust gas temperature at idle (and above)...

John

That sounds interesting John - I'm always looking for other uses for my little toys, and I already know how hot the gas grill gets

Seriously, do you just look for equal temps, or is there a target temp you expect for most efficient combustion?

[john.p.clegg]

I just try for equal gas temp...

John

P.S. someone will no doubt know what temp to look for...

[Foxie]

I just try for equal gas temp...

P.S. someone will no doubt know what temp to look for...

John,

I found a cheap IR thermometer great for getting the final balance. IMHO, the actual temp at idle would be variable, depending on rev setting, ambient temp, cooling fan type, stat setting, and an exact 'target' temp would not be that important