Yah, cool is the operative!
So, I see a few Chinese digitals for a couple bucks. On further mulling (still snoozing)will see if I can pull the brass plugs in situ and thread the thermistors or thermocouples. I think thermistors okay since temps should be under 100C. Btw, the readings I said should be in C not F
Thanks for the ātipā Max, Iāll give it a try the next time I have her out for a drive and see what I come up with. My milage on this last trip was screwed up because I was unintentionally adjusting the carbs for a fuel supply issue that has since been remedied (debris in the fuel tank).
Cheers,
LLynn
Lynn
Found cheapo fridge eBay led thermometers for under 2$ with 1meter probes. Going to get a dozen plus one in case of defect. Iād think this would be good for the Stroms and SUās. Wanted more length to get inside cabin but think theyāre long enough to house proximal the wipers near the bonnet edge.
After 9 years of ownership I still have to set my Strombergs. Iām following your experiment with interest.
Mind you, up to 22mpg/us isnāt bad for a V12.
Ole, I think you misread. I got 15.6 not 22 mpg but coincidentally thatās what I get on my Viper06. I donāt know how the strombergs do on the v12 but I certainly like the rumble I get over that of the v10 viper!
Find yourself a common point on each carb and see what you get. Itāll be a lot easier to track 4 readings versus the 12 throats on the Webers. Iām thinking I can splice the thermistor wires and pull them inside to set on the dash instead of Mounting them by the wipers.
Suggest you measure on the rear flange area which should see the fuel spray just as it dumps into the intake and the gasket thermally isolates it from the intake metal.
If it shows results to your satisfaction you might do a drill hole to set thin wire thermocouples so you can do what Iām doing and do highway readings as that may have more meaning than idle conditions.
As I was writing I realized there is an air corrector needle right on the mounting flange of the Webers. This has no utility as the instructions say to keep it snug and only used if the carb has unbalanced airflow. Going to look at that as a location for the sensors! Also seems to be ideal as it sits right behind the throttle disc where I anticipate good atomization.
So, lemme get this straight: The fuel vaporizing absorbs heat, thereby cooling the surrounding carburetor. Presumably, the more fuel is vaporized, the cooler it gets. So a carb running colder than the others is presumably running too rich. Correct?
And perhaps doesnāt move much with throttle. Wider open, moving ten times as much fuel, also moving ten times as much air, so the temperature change might remain relatively stable.
Iāll be interested in seeing if the relationship between carb temp and outdoor temp remains fairly constant over different cars and different conditions. Presumably it doesnāt matter what car weāre talking about, the fuel/air ratio should be similar, so they all should register nearly the same ā provided theyāre not being influenced by engine temp or other factors.
Sorry I wasnāt clear. I get 22mpg without having adjusted my 4 Strombergs since I bought the car in 2010 and it limped on 6 cylinders.
Rebuilt the carbs and ignition. Set the ignition but havenāt synchronized the carbs yet. Must be OK (ish) I guess.
I might look at your temperature idea to get a feel for how rack carb is set up and works.
Ole, considering that youāre getting 22, and others may opine, isnāt that pretty good mileage? As noted in previous discussion you might want to weld up some oxy sensors on each bank. That, with air-fuel gage will really give a tighter feel for making adjustments. When I noticed the weak carb and adjusted I watched the gage and it reflected the improvement by a slight enriching but not rich. The drop in temperature followed.
Kirb, it would be interesting to see the temps of the carbs but Iād guess the geometries and masses of the intake systems and sensor placement would be significant. Anyways, thatās what makes research so intriguing. If anyone does do the oxy sensors get the heated version for rapid readings. Also any one will do. I recall buying 7 pack for a buck apiece. Good to do as Iāve fried a few by mixing the wires. Also most repair shops conveniently replace good ones and likely will give them up. Theyāre easy to check with a torch and voltmeter
Somebody needs to see what kind of temp readings can be obtained from a modern EFI car with closed-loop fuel control. Thatād be interesting, although I dunno how it could be accomplished; AFAIK, the area between the injector and the intake valve is usually pretty short and difficult to get at.
If you want, you can run K-type thermocouples in the exhaust, so long as you build a conditioning circuit to amplify the voltage so it can be either datalogged or drive a 0-5v gauge. From memory, the probes drive an AD595 chip and will give you temperatures accurate to within a few degrees centigrade. (It is important that all of the connectors are exposed to the same temperature - this is a thermocouple.)
There are two very convenient ways to access the exhaust ports:- 1/ through the air injection ports on where the inlet manifold would have sat; 2/by drilling either the left or right hand bolt holes holding the water housings on the heads. If you look, youāll see these are directly above the exhaust ports and are at the edge of the cylinder heads.
I currently run 12 EGT sensors on my v12 and 4 lambda sensors on the downpipes. The whole lot is logged by the Megasquirt-3 unit. (The lambda sensor location is borderline too-close to the exhaust ports at the downpipes - the sensors may overheat here.)
There are pictures in the photo albums in the old website section.
Whilst measuring inlet temperatures may give you a steer as to what is going on, measuring exhaust gas temperatures (āEGTā) is going to be a more reliable and direct method, as ambient temperature conditions around the engine bay are not going to be constant from carburettor to carburettor without perfect airflow all around the heads and that means a different amount of fuel will be vapourising in the inlet and condensing on the (albeit short) inlet runners.
As with lots of other carburettor diagnostics (like āColourtuneā) you are measuring and altering what you can at idle and extrapolating, whereas what you are really interested in what is going on under normal running conditions on the road. This might sort of make sense with Strombergs, which have almost no scope for alteration other than jet height and needle profile, but the Webbers can be set up totally differently at idle versus full load because of the plethora of adjustable throats and screws.
kind regards
Marek
http://www.jag-lovers.org/snaps/snap_view.php3?id=1413043806
Some of the pictures may have been repeated elsewhere on this site.
For doGās sake, donāt fix it!!!
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If it works, leave it alone. My thought exactly.
BUT, it would be nice to find out why it works so well 
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Kind of reminds me of the golden goose fable;
Opened up the goose to find out what makes the eggsš
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Speaking from looooong experience: back away from the engine bay.
When youāre asked, āhow did you DO that?ā, answer with, āQuite well, donāt you think?ā
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As the provider of your MOD gearbox, which even worked eventually, I might have thoughts on that topicā¦
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