TBI Carbs

[Bubbleboy]

I am having these on again off again thoughts with regard to the various TBI Carbs on the market. I am looking for a carb for my Corvair conversion I am installing in my Pietenpol Air Camper build.

 

What would be ideal is to chat with someone who has fitted one to a Corvair and what the results were. I know there has been discussion on these here in the past but no actual feedback. What are the negatives of them?

 

The MAS-3 carbs have been used on the Corvair's but I like the positives of these TBI's but am not 100% convinced yet. The ones I have looked into suit a wide HP range and I am trying to figure out how you can adjust the high end mixture. In a normal carb you can change jets to suit. These TBI's dont have that option. How do they know what the exact fuel mixture needs to be or is it an air flow / pressure thing that does it automatically.

 

I know how the TBI's work with the little holes on the meter bar and how more are uncovered as the slide is retracted but I thought it would need to be more of an exact science than that.

 

Anyone have one of these?

 

Scotty :confused:

 

 

[Brett]

Having still not even ran my Aerovee and Aerocarb I have no real advise to give but as A bit of a tinkerer I have bought a wide band Air fuel ratio gauge and am going to bung the sensor in the correct spot on the exhaust so that the gauge on the dash can tell me the excact Air/fuel ratio on all throttle settings. The gauge can tell the ratio from about 11-1 to about 17-1 ratio. It's I guess something I don't really need but it's simple to install and wire up and will be a guide only ,,I dare say it will only at best be reasonably accurate however and with a set of egt's and cht sensors I/m sure I can get it set correctly so I wont have to deal with tuning issuses whist trying to test fly a brand new airframe plus limiting the ground running time tuning it for it's first flight. Other drama is they only work with unleaded ,,,Avgas will slowly destroy them . The aerocarbs although simple have quite a wide range of adjustments but the only thing that makes me cringe about them is that they will leak fuel if the engine is not running,, so fuel off and full lean till your ready to start,, still no big deal once aware of it.

 

 

[Bubbleboy]

Hi Brett......the problem of fuel flowing out after engine shut down is a big problem as far as I am concerned. Another type has a regulator which supposedly overcomes this issue. No vacuum - no fuel flow.

 

I guess I am struggling with the idea that one carb can cover a range of engine capacities with out being able to be "re-jetted" to suit MY particular application as can be done with a traditional carb.

 

There has forever been so much dancing around this subject and no one will say 'I have one and this is how I have found it", preferably a Corvair .

 

Is it only the Aerocarb that cant run on Avgas? What damage does it do too it?

 

Scotty :thumb_up:

 

 

[Brett]

Aerocarb is fine with Avgas it's just the sensor for the gauge I was talking about can't handle the lead.. After a few hours of flying I'm sure I won't need the gauge anymore as it should be I hope tuned correctly. You do know that when you get an aerocarb in the box comes 3 different needles for main adjustments and then the needles can also be adjusted inside the carb for fine tuning ,, I have no idea but I expect so do the other versions that can be bought.

 

 

[Methusala]

Hi Guys!

 

Many people have fitted Stromberg constant velocity carburettors to engines such as VW. Similar carb to Bings fitted to millions of BMW bikes...and,oh yes most Rotax. I had a Revmaster fitted with a Posa carb( said to be an acronym for "piece of s..t!) and I thought that it was the most useless, dangerous rubbish ever concieved. However it would be great to waste a lot of time if you wished to reinvent the wheel! Don

 

 

[Bubbleboy]

Hi Dexter...yes please keep us informed on how his engine went with the TBI carb.

 

Brett...im not sure if these Ozzie ones come with the different needles. Worth investigating.

 

Don...I dont see the TBI as reinventing the wheel. Its another option available to me here in OZ. Sure I can get a MAS-3 from the USA but if these TBI are as good as suggested, well I want to investigate it. They look simple to set up and run...if they work. I dont need it now so have the time to hear experiences from others who have tried them.

 

Thanks guys

 

Scotty