Thorttle Body Sync Fix

I'm thinking about performing a complete TBS as out lined by 3dogs in this link, Clicky. If you have done this, has it reduced the buzz experienced aboue 3800 RPM? Also, was it easy to screw up?

Yes it does reduce the buzz somewhat but I felt it more in smoother throttle response. On my 06 #1 & # 4 needed a slight tweaking only. Took longer to set it up than to synch the TB's. Make sure your tool has restrictors in the vacumn lines. I really like the Morgan Carbtune tool.

Yeah, I have done the normal TBS. It made a big difference all the way up to about 3800 rpm. But the buss is pretty severe above that. So I'm trying to get a feel for if doing the complete TBS will make the difference above 3800.

Let me toss in a purely theoretical observation:

First off let's assume (ASS U ME) there are no other extraneous factors screwing up the observation.

Next, we diddle the air screws at idle and achieve complete vacuum bliss at idle. But, being the smart homo sapiens that we are, we know that those silly air screws provided by YammaMama have the biggest effect at idle, and progressively provide diminishing effects as the rpm and (more importantly) air flow increase.

My initial response is, why bother have air screws? If their main effect is at idle, who gives a royal rat's ass how well synchronized the throttle bodies are at idle. If there are vibrations there, they would be minor. To my way of thinking, and I could be way wrong, I want the synchronization to occur at a higher usable rpm, like in the 3500-4500 rpm range.

I can live with a little buzz at idle or even at WFO, but cruise speeds are where we live 90% of the time. Wouldn't we want that to be the smoothest possible?

yessir

Fred W said:

Let me toss in a purely theoretical observation:
First off let's assume (ASS U ME) there are no other extraneous factors screwing up the observation.

Next, we diddle the air screws at idle and achieve complete vacuum bliss at idle. But, being the smart homo sapiens that we are, we know that those silly air screws provided by YammaMama have the biggest effect at idle, and progressively provide diminishing effects as the rpm and (more importantly) air flow increase.

My initial response is, why bother have air screws? If their main effect is at idle, who gives a royal rat's ass how well synchronized the throttle bodies are at idle. If there are vibrations there, they would be minor. To my way of thinking, and I could be way wrong, I want the synchronization to occur at a higher usable rpm, like in the 3500-4500 rpm range.

I can live with a little buzz at idle or even at WFO, but cruise speeds are where we live 90% of the time. Wouldn't we want that to be the smoothest possible?

Click to expand...

I couldn't have said it better myself

Yes and No, but you have to be patient.

The idea of this deeper balance is to get the Throttle Blade Vacuum balance as close as possible and then with the Air Screws as the Fine Touch Balance. My 5 Star mechanic was impressed with the results.

It just takes 2-3x more time to get this job done as opposed the the Normal TBS.

Good Luck with your Adjustments.

I tried your idea, Fred. I'm not impressed with the results.

What I did was lock the throttle at about 4000rpm and then sync'd the air screws. At idle the throttle bodies were no longer sync'd. I didn't notice any difference in vibration when cruising at 4000rpm, but I did notice that the idle is very rough.

I guess I'll have to try the complete modified sync procedure for the best of both worlds....

Syncing is primarily for emissions compliance. If it's not synced within the allowable limits the oxygen sensor may not perform adequately for fuel and emissions control. The exhaust cats may be compromised.

The first section of the maintenance chart addresses the emissions control components. Adjusting the idle speed and syncing are included.

So, It kinda sounds like this is something I should do. I'll see what happens

Harald said:

I tried your idea, Fred. I'm not impressed with the results.
What I did was lock the throttle at about 4000rpm and then sync'd the air screws. At idle the throttle bodies were no longer sync'd. I didn't notice any difference in vibration when cruising at 4000rpm, but I did notice that the idle is very rough.

I guess I'll have to try the complete modified sync procedure for the best of both worlds....

Click to expand...

That wasn't my idea, to use the air screws at 4000 rpm. I was just posing that the balancing needs to be done at higher range, but not via the air screws. Any misbalance at the higher engine speed would have to be adjusted out via the throttle plates.

yes I'm planning on doing the complete TBS. I've done the air screw one twice now, and there was much improvement in the lower RPM's, but no change above 3800. So, that's kinda why I was asking about what other's that have done it have found.