Throttle body balancing and Tune ECU

[sleeves]

Okay this should be easily answered.

I have many times balanced the throttle bodies on R3's, without the stock air box its pretty easy while using Tune ECU. No problems with this.

From reading other threads I know that the vacuum hoses crack with age and may need replacing. I'm also OK with this.

So I was thinking about this today and went to the garage as it occurred to me that each throttle body has a vaccum tube. However these all join to a common tee (well three in and one out fitting) this I imagine goes to the sensor that measure the vacuum.

If this is the case how does the Tune ECU, Tuneboy, whatever, know the vacuum at any given time on each cylinder? It obviously does as its displayed. Surely you would need a transducer for each cylinder? I looked and could not see three, just one larger tube going to one sensor.

Am I looking in the wrong place or is there some trick here? This is really bugging me right now. It may be that the connection "tee" thingy IS the transducer, but the program also has the average vacuum displayed one another page.

Please satisfy my curiosity here.

 

[R-III-R Turbo]

Cylinders induct one at a time, so only one cylinder at a time can pull the vacuum that the common MAP sensor is reading at that time

 

[sleeves]

Cylinders induct one at a time, so only one cylinder at a time can pull the vacuum that the common MAP sensor is reading at that time

Right, but it happens pretty darn quickly, so it must be able to switch measure and transmit in milliseconds correct? That would explain why the update on the Tune ECU jumps around sometimes also as it looks like it updates every second or so.

Thanks for that I can rest easy now.

 

[mr hunt]

My understanding (learned from the Triumphrat site) is that having 240° firing interval means each cyl fires once in every 2 crank shaft rotations. This means each cyl fires once every 0.4sec's @ 900rpm. I guess if The software 'knows' where the crank/cyl's started from it can attribute the vacuum to the appropriate cyl???

 

[HansO]

at the rear of motor there is the Crank Angle Sensor that is how the ECU knows which cylinder is sucking and when to fire up the Spark plugs

 

[Muff]

Okay this should be easily answered.

I have many times balanced the throttle bodies on R3's, without the stock air box its pretty easy while using Tune ECU. No problems with this.

From reading other threads I know that the vacuum hoses crack with age and may need replacing. I'm also OK with this.

So I was thinking about this today and went to the garage as it occurred to me that each throttle body has a vaccum tube. However these all join to a common tee (well three in and one out fitting) this I imagine goes to the sensor that measure the vacuum.

If this is the case how does the Tune ECU, Tuneboy, whatever, know the vacuum at any given time on each cylinder? It obviously does as its displayed. Surely you would need a transducer for each cylinder? I looked and could not see three, just one larger tube going to one sensor.

Am I looking in the wrong place or is there some trick here? This is really bugging me right now. It may be that the connection "tee" thingy IS the transducer, but the program also has the average vacuum displayed one another page.

Please satisfy my curiosity here.

I was thinking the same when fitting the RamAir to the bike. Thanks for asking and the replies

 

[warp9.9]

Before you adjust them make sure you have the free play in the throttle cables . The linkage all thru the throttle bodies has springs some act as tension like on the adjusting screws. But some in the linkage are for absorbing the tension and any other binding type action.

 

[sleeves]

This explains why even one leaking hose will royally mess up the bikes fueling across all cylinders.

Thanks again to everyone.

 

[leatal]

I read somewhere that if replacing the MAP vacuum hoses, you want to use the same length as OEM for all three hoses. Is this the reason for it?