Throttle bodies setup

[bonzza82]

Good evening,

I was just wondering what the best air flow metre reading on the synchrometer should be for optimum results when tuning in the throttle bodies, any help would be great thanks

[m4tti]

The value on the synchronometer is really of secondary importance. Your primary goal is to get all throttle bodies reading the same. Once they are all in line you can adjust the idle via the idle screw, which will ultimately reduce or increase the value on the synchronometer... If that makes sense

[bonzza82]

Hi,
Thanks for the reply, yes that does make sence i have them all at the same value of 6cfm on idle at just under 1000rpm, but didnt know if the car would behave differently if say set to 5cfm or 7cfm at idle,
i will probably have a tinker tomorrow to see

[clive f]

just make sure the engine is nice and hot after a good run when setting them up.

[K4TRV]

bonzza82 said:

Hi,
Thanks for the reply, yes that does make sence i have them all at the same value of 6cfm on idle at just under 1000rpm, but didnt know if the car would behave differently if say set to 5cfm or 7cfm at idle,
i will probably have a tinker tomorrow to see

Enjoy your tinker.................but as said above, the object is to have them flowing the same amount. You appear to have done so and also have them below 1000 rpm, another goal reached.

The adjustment of two banks of three throttle bodies is slightly more than a tinker. It may seem relatively simple to "play" with them to see what the effect maybe? But I think you will find that what you have is something most of us would like to have!! The adjustment is an art form, especially as the design of the spindles and linkage is without bearing or seals.

My comments are just to try and warn you away from "tinkering" unless you have recently refurbished the throttle bodies and have some experience and knowledge of what you are doing?

If you do continue and readjust them, I also hope you also have the MBE Software to re-set the throttle and Adaptives afterwards to take account of the changes?

If you do really know what you are doing, please ignore my warnings, what do I really know?

Just trying to help?

T

[m4tti]

To be honest I had a set of badly done roller bearing bodies and went back to felt bushed bodies which balanced fine.

Explained in my rebuild thread here.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[bonzza82]

Hi T,
Thanks for the reply, I agree the balancing of the two banks is a little bit of a art form and great when set up right, I have just recently balanced them up after the car didn't seem to pull quite right but now pulls very strong, some of the bodies were nearly 1.5cfm out compared to others! I do have some experience in setting up carbs and tuning them in so I just set mine to 6 on the scynchrmeter as this would be a good starting point but as I say I didn't know if there was a optimum to set them to for best results? I do have the mbe software aswell so can check and reset aswell , the first bank is at 15.5% and second bank is at 15.2% at idle not too bad is it?
Cheers
I

[bonzza82]

Hi T,
Thanks for the reply, I agree the balancing of the two banks is a little bit of a art form and great when set up right, I have just recently balanced them up after the car didn't seem to pull quite right but now pulls very strong, some of the bodies were nearly 1.5cfm out compared to others! I do have some experience in setting up carbs and tuning them in so I just set mine to 6 on the scynchrmeter as this would be a good starting point but as I say I didn't know if there was a optimum to set them to for best results? I do have the mbe software aswell so can check and reset aswell , the first bank is at 15.5% and second bank is at 15.2% at idle not too bad is it?
Cheers
I

[K4TRV]

Hi B,

Good man. Sounds like you have a solid motor and ancillaries!!

Having had to engage Dom Trickett & his 4.3, I also had the throttle bodies refurbished. That does make such a difference as does having a 4.3!!

The times I chased my tail trying to set the balance pre-failure, then watch adaptives drift increasingly towards +25% and some!!

Enjoy.

T

[m4tti]

The throttle pots should be around 11 engine off, from memory.

Edit.
Should have read 11 engine off, 15% at idle, 94% fully open.

Edited by m4tti on Saturday 25th October 08:29

[twinreal]

15% is correct.