| Author |
Message |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 382
Registered: 5-2001
| | Posted on Sunday, October 20, 2002 - 8:11 am: | |
Peter,
I've used set of 4-ColorTunes on my GTS and found them to work pretty well. They respond very quickly to mixture adjustments. They are however, a little difficult to read when tuning the front bank on a 308. The other thing is they can only be used to tune the idle circuit, as the clear insulator is a little fragile. This means, they are not suitable for main jet evaluation or under load as on a chassis dyno. When you build up some experience with them, you can detect other problems, like low air flow, balance issues. The instructions that come with them are pretty good. All in all, an effective tool IMHO.
Exhaust gas analyzers evaluate the gas content down stream of the cylinder head and are much slower acting. Inexpensive meters will measure only CO and air/fuel ratios, which is probably sufficient for your purposes. To measure the true byproducts of combustion, you must sample the gas content before it is affected by any emissions equipment. I haven't done this on my 308 yet because it is currently fitted with cats and air injection. If you were to sample the gas content using the factory gas analyzer tubes and temporarilly disable the air injection, you could presumably get true readings. Some of the gas analyzers are also protable, so on the road testing is possible, even the main jet system could be evaluated.
I bought two ColorTunes at r.d. enterprises in PA.
http://www.rdent.com/pages/tools.html
They also have portable gas analyzers.
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Dr. Mike Adams (Drmike)
New member
Username: Drmike
Post Number: 5
Registered: 5-2002
| | Posted on Sunday, October 20, 2002 - 12:48 am: | |
I have used a colortune ( 3 of them at a time, actually ) to do the carbs on my Daytona for 2 years. If you follow the instructions, you will end up a bit lean. Eventually, I learned to just richen it until I saw allot of yellow; then lean it until the yellow just disappeared; then 1/8 turn richer.
Another nice thing about the colortune, is that it makes it REALLY obvious when you have a clogged idle jet. |
William Badurski (Billb)
Junior Member
Username: Billb
Post Number: 80
Registered: 6-2001
| | Posted on Sunday, October 20, 2002 - 12:32 am: | |
Peter,
I bought two Colortunes and used them on my Daytona. Easy to set mixture with them, but found that actual driving after setting carbs with them was too lean. Went back to old method of setting them up for fastest idle, and color check of plugs to get correct main jets worked better. |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 2095
Registered: 12-2000
| | Posted on Sunday, October 20, 2002 - 12:11 am: | |
I'd be interested in finding out the exact setting for fuel mixture, instead of doing the lean-cut method with my carbs. I found the Gunson website and in addition to their Colourtunes, they also make gas analysers. Which is better to use? It would be neat to have an actual number value and if the unit provides readings also for HC and NOx, that would be better. But I've also read the experiences of the few people who've used the Colourtunes and said they were easy to use (also how inexpensive it is compared to the analyser, even if I get enough to do all eight cylinders at the same time).
http://www.gunson.co.uk/acatalog/Gunson_Catalogue_Exhaust_Gas_Analysers_Mixture_Control_5.html
I'm thinking either one could be useful for Ferraris that I'd get in the future, that run on Bosch F.I. (although for those systems, I'd probably need to use them only once).
I'd like to hear people's opinions about this. Also if anyone knows about other devices avaliable (preferably avaliable on this side of the Atlantic)... |
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