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I understand this exercise was to to damp the vibes...just wanted to know if there was a change in pedal action feel as an addition.
ever driven a manual car with a counterweighted ****? that's what I was equating the experience to.
how does this change the response of the engine when letting OFF the throttle? do you experience more RPM rev hang? Does it affect downshifting of the transmission since more weight is added to the pedal thereby slowing the speed at which the pedal releases? Did you have to adjust any spring tension on the throttle body due to the increased mass on the pedal? Will this affect the spring tension on the pedal assembly and make it weaker over time?
how does this change the response of the engine when letting OFF the throttle? do you experience more RPM rev hang? Does it affect downshifting of the transmission since more weight is added to the pedal thereby slowing the speed at which the pedal releases? Did you have to adjust any spring tension on the throttle body due to the increased mass on the pedal? Will this affect the spring tension on the pedal assembly and make it weaker over time?
Reporting no differences in any of these areas .....after three years.
This same question arose earlier .
The pedal is on a vertical plane and hinges at its base.
Spring tension is applied near upper half, so return leverage force is more than adequate and not discernibly affected.
Adding mass really makes difference. In reducing vibration at pedal....
Newer vehicles are true fly by wire..so no throttle cable vibration from engine....but are still hinged at floor.
I recall Mercedes-Benz employed a rubber cover over their gas pedal to dampen this vibration (which was not 100% effective), and Lexus attempted more isolation at the source, but used only a plastic pedal, which, in view of my reported improvements, was not 100% effective either.
Toyota Celsior Accelerator Assembly parts diagram depicts a weight near the throttle cable attachment point, while it's American Lexus counterpart does not.
While this scheme does not dampen chassis vibration transmitted via floor mounted pedal pivot, it attenuates engine vibration transmitted via a taught throttle cable.
Cesior and LS400 exploded parts diagrams depicting differences; This is system on U.S. LS400 This appears to be an alternate system that does not pivot at chassis. Perhaps used on Canadian models. Celsior diagram depicts damping weight (at least it appears to be a weight)
Resembles the weight the OEM welds to the shifter - transmission rod to dampen vibration.
Toyota Celsior gas pedal assembly depicting cylinder at top of accelerator rod just below where the accelerator cable affixes.
Plausibly it dampens engine vibration transmitted through the cable, and, or, it helps balance the pedal assembly.
Vector Custom Fabricating in Chicago welded a .750 inch diameter by 1.50 inch long solid steel rod, which was "coped" to the accelerator rod diameter to the same area depicted in the parts diagram.
I observed the accelerator rod now actually balances on the pivot...and when installed, it does not hinder or cause unwanted pedal movement...
Although I have filled the back of my gas pedal and pivot base with Lead to dampen any chassis vibration, I felt the pedal rod itself had some resonance...
I installed a bronze bushing in my pedal pivot some time ago, and if anyone is contemplating this project should address that issue first.
Solid metal rod welded to top of accelerator rod.. Profile view. The added metal rod was coped to accelerator rod diameter before welding. Accelerator pivot installed after added cylinder was painted. The accelerator cable is not connected so as to demonstrate it leans back at the top, so not exerting any weight to stress springs or actuate pedal. It feels more balanced.
If you want to take up a real engineering perspective out of what you're doing, you can work up some force diagrams. If your pedal vibration is that bad you might have something going on other than just the nature of the mechanical linkage. How are your motor mounts?
If you want to take up a real engineering perspective out of what you're doing, you can work up some force diagrams. If your pedal vibration is that bad you might have something going on other than just the nature of the mechanical linkage. How are your motor mounts?
The accelerator pedal is mounted via a ball and socket bracket which is mounted directly to the chassis.
The accelerator rod pivot block is also bolted directly to the chassis.
The LS400 employs an accelerator cable that when depressed becomes taut and transmits any engine vibration or noise (think string phone)
So, the engine/trans mounts are replaced, but the pedal picks up everything going on in the chassis (worn concrete surfaces are noisy) and engine, irrespective of condition of engine mounts.
After bushing the pivot block, filling its base with Lead, filling the gas pedal with Lead, I noticed difference in isolation.
Thereafter have driven several LS400's and can really feel the road and engine in their gas pedals.
Did the same on my Mercedes some years ago.
Same difference..but Mercedes employed a Rube Goldberg accelerator linkage configuration and rubber cover over the pedal to isolate the pedal from chassis and engine.
Toyota should have used a rubber pedal cover.
Now this last project came about while perusing the Celsior parts diagrams and observed what appeared to be a smal metal cylinder mounted at the top of the accelerator rod at a 90 degree angle, just below where the accelerator cable connects, suggested it would dampen any residual vibration or noise making it's way into the pedal via the accelerator cable.
As example, the stereo system induces vibration into the chassis at elevated volumes and heavy bass notes could be felt in the gas pedal, now negligible.
If you want to take up a real engineering perspective out of what you're doing, you can work up some force diagrams. If your pedal vibration is that bad you might have something going on other than just the nature of the mechanical linkage. How are your motor mounts?
Located a Toyota technical training manual on NVH (Noise, Vibration and Harshness) depicting images adding mass damper (weight) to accelerator pedal linkage as a means to reducing perceived pedal vibration.
The Toyota branded Celsior depicts a mass damper atop gas pedal linkage..so Toyota already perforned that investigation
Was flipping through this same book at the indy's shop the other day. Has some good info in there. Do you notice this in yours? I've not felt it with ours.
Was flipping through this same book at the indy's shop the other day. Has some good info in there. Do you notice this in yours? I've not felt it with ours.
The gas pedal is "hinged" to the chassis via bracket and the gas pedal rod via pivot block to the chassis.
In addition, the taut accelerator cable is a conduit for engine vibration(s).
So all of these mass-loading treatments become very noticeable when you drive someone else's LS400 without added mass.
The gas pedal is "hinged" to the chassis via bracket and the gas pedal rod via pivot block to the chassis.
In addition, the taut accelerator cable is a conduit for engine vibration(s).
So all of these mass-loading treatments become very noticeable when you drive someone else's LS400 without added mass.
I've had the vibration through gas pedal issue with my 94 since i've had it, new mounts and everything. So you're basically saying just add some density to the pedal somehow (I don't feel comfortable handling molten lead) and it will solve this issue?
I've had the vibration through gas pedal issue with my 94 since i've had it, new mounts and everything. So you're basically saying just add some density to the pedal somehow (I don't feel comfortable handling molten lead) and it will solve this issue?
If you feel uncomfortable filling the back of the pedal, then add lead to the pivot base and a solid circular weight at the top of accelerator rod as depicted in this post and Toyota NVH diagram. "Cope" the added rod.
When pouring molten Lead, heat it just until melting point....do not go crazy on temperature or you risk distorting of burning through plastic.
Before pouring molten Lead , set the plastic part in a pan of cool.water.
08-06-18 | 02:40 PM
