Balancing Roller Barrel Throttle Bodies

[tomlil01]

Hi,

I am trying to balance the roller barrels on my R300K, and I had a few questions that maybe someone with more knowledge might be able to help with.

• With the idle set to 1000 rpm, I am only getting about 3.5 on each barrel with my synchrometer. Is this normal it should it be higher? In order to achieve a higher air flow I assume I would need to set the idle to more than 1000rpm?
• In order to get the roller barrels as closely balanced as possible, they do not all seem to be open 1mm at idle. Rather the two barrels towards the back of the car are open ~1mm, and the two barrels towards the front of the car appear to be completely closed (as far as I can see).
• How does the balance adjustment screw work? Does this balance between all 4 barrels or just the left 2 vs the right 2?

Thanks

Lee

[ECR]

The object of balancing your throttle bodies is to ensure that each cylinder is drawing the same amount of air. If they are all drawing the same as you say they are balanced.

im not familiar with the roller barrel setup but if there's only one adjusting screw that will balance the front pair to the rear pair. On my Jenvey doe bodies there is an additional bleed screw on the bodies themselves to balance between the two on the same body. Don't know if that exists on roller barrel setup...

[Geoff Brown]

I do believe that early RBTB as on K series were split in to pairs so require individual adjustment for the correct opening.

Not sure of the other requirements on K series but surely must be the same as a Duratec ? 

If so the the throttle gap in the 'closed position' (ie tick over) should be 6mm. Idle air flow between 5-6Kg per hour with idle at 900-1000rpm. Adjust using air bleed screws situated on the engine side of the bodies.

[tomlil01]

Thanks for the responses.I've been trying to follow this guide:

http://www.bikerhouse.com/testsite/minister2011/support/roller_barrel_setup_k-seriesr.php

If there is some way to balance between the two individual throttle bodies in each pair, then it doesn't mention it. I'm not really sure what I'm looking for, but I can't see anything obvious that might be this "bleed screw".

The guide says to use 1mm opening for idle.

Lee

[John Vine]

These are the bleed screws on my R400D:

As I recall, my old 1.8K Supersport-R (same RBs as yours, I think) didn't have these bleed screws at all.

 

This is CC's Workshop Notice on the subject:

W O R K S H O P N O T I C E

No: 373 . Issue 1


Setup of Roller Barrel Induction Systems

To:- Production and Service
From:- Nathan Down

In order for an engine fitted with Roller Barrel induction to pass SVA as well as have best possible driveability it is necessary to perform the following setup.

Firstly, Set the balance of the two pairs of barrels as closely as possible. This is achieved by unlocking the small 6mm lock-nut on the throttle operating lever and adjusting with a allen key.

Secondly, set the air intake flow rate. This is done by unlocking the 7mm lock nut on the idle adjusting screw (nearest the engine – the other one is for full throttle). At idle (900 – 1100 rpm) the Roller Barrels must draw in 5 kg/hr per cylinder. If all the cylinders are not drawing in the same amount of air then they should be set so that each pair draws in 10kg/hr i.e. if cylinder 1 draws 5.5 and cylinder 2 draws 4.5.

Lastly, the throttle potentiometer can be set. This is achieved by fitting the in-line adapter harness (see note below) and connecting a multi-meter to the provided ports. Set the potentiometer to between 0.43 – 0.45V by releasing the lock screws and rotating the potentiometer body.

If there are any problems please do not hesitate to contact me.
DATE: 18-12-2002 ISSUED BY: N.Down

NOTE from CC (Mark Rider) on 3 January 2013 re “inline adapter harness”:

“We don’t do a harness but all you need to do is:

Get a volt meter and with the ignition on put the probes to the wires that go in to the TPS sensor and turn the sensor until you get between 0.43-0.45 Volts by loosening the bolts holding it on

And that’s the TPS set up”

 

No mention of the recommended 1mm gap.

JV

[StevehS3]

Is this of help. Apologies for it being photos - don't know how to attach a file but I can email it if it's what you need.

 

[tomlil01]

thanks, JV. This is interesting. So, it sounds like I should probably increase my idle to 1100 (or perhaps even higher) to try to achieve this air flow of 10 per pair. At the moment I have 3.25, 3.25, 3.25, 3.75 at 1000rpm idle, so nothing like 10 per pair. 

[tomlil01]

Thanks, Steve. This is actually the guide I was using. 

[Kimble]

Hello!

Remember to make sure that the car is warmed up when setting the idle at 1k RPM.  I think the adaptive map 'adds a bit of choke'.

When I set mine, what is ~1.3k rpm (cold) drops to ~1k warm.

[tomlil01]

Thanks, yup, I'll remember to let the car warm up first

[oilyhands]

In my experience of around 300 sets of TBs, you would normally expect an 1800 to draw around 5-5.25 kg/hr through each barrel, lower airflow can sustain an idle when hot as the ECU will ramp up advance to kick the idle up, but you may have trouble with the cold start if airflow < 4 kg/hr.

Dave

[tomlil01]

Thanks, Dave. The car seems to keep running ok with ~3.5 on each barrel. I can obviously increase the idle to increase the air flow to something nearer 5. I am just a bit confused, as then my idle will be above 1000rpm, and 1000 is what they recommend in the setup guide. Is it normal to have to use an idle above 1000rpm to achieve this air flow?

[oilyhands]

 No it isn't normal, I would check your flow meter carefully, some have air bleeds which by pass the metering flaps and give a lower reading, this allows for more sensitivity when a lot of air is being drawn through. Ensure there is not an air bleed that is exposed.

Oily

[Nick T]

Kind of on the same thread, what is the preferred balancer that is used as I would like to check my TBs and need to buy something suitable?

thanks

[Tony Whitley]

Link to the Minister PDF

@Nick T: Synchrometer  also available from other suppliers.

[Nick T]

Tony,

many thanks

[Nick T]

Tony,

many thanks