Improved Throttle Response For Free

[hEaT]

On my 85 I always noticed a very short pedal travel and it was quite stiff. The linkage and springs were all well cleaned and lubricated, but it didn't help much. I had some free time today and took the throttle linkage off the TB and disengaged the spring closest to the passenger side, cleaned, and re-greased the linkage pieces. I also unhooked the mount on the upper intake and spaced it back about an inch using a longer bolt with a few nuts to hold it in place. The end result was the pedal having about twice the amount of travel and it being much touchier on initial tip-in. It does space the pedal up higher so it takes some getting used to when heel-toeing, but make it easier since you need to blip the throttle less. With one of the three springs disconnected it does make the throttle easier to press. By having the mount moved it also pre-loaded the in-line spring less making the throttle easier to press as well.

Before I started working on it I noticed when the pedal was fully depressed in the car there was still some room for the linkage to move by hand. The pedal would bottom out against the carpet and floor before it could go fully WOT. With the new linkage location this is not the case. The pedal still bottoms out at the floor, but there is zero play in the linkage at the TB. Does it make the car faster? I'd say not at all. It does make the car feel much peppier, pretty much the same feeling I got by swapping to a larger TB on my Focus. No more power, just smoother and "sportier' throttle response. I believe by moving the mount on the lower intake it alters how the progressive throttle linkage works and make it's less progressive and more linear. Exactly what I wanted to accomplish. If anyone is actually interested in doing this to their car or just wants to see what I did, I can grab some pictures. Just thought I'd share.

[Garret]

I'd like to see some pictures as I have the same complaint about my car

[hEaT]

I'll try to get some tomorrow.

[Garret]

That would be super

[Ray]

I'd like to take a look at that Joe.

[DSPXR4ti]

Show us the pic's Please...! anything help at this point.

Ben

[Rustjunkey]

Ditto,
Rustjunkey

[hEaT]

Ok, here are some pics. Hopefully they are self-explanatory. I'll see if Ray can stop by and give some objective observation. Unfortunately, he did not drive my car before the mod, but it is easily reversible for testing.

Here is where the pedal is now in the car in relation to the brake:





Here are some pictures of the throttle bracket spaced away from its original position:







Here's a video. Take it FWIW. Take into account the car is 99% stock powertrain wise. No cat, but stock downpipe and elbow. Cone filter mounted on the VAM and MBC set to 15psi. Yes the car was warmed up and sorry about the foot

http://www.youtube.com/watch?v=xnS84cioq44

[Rustjunkey]

Joe,
Cute foot! Hopefully none of the forum members have a foot fetish or you may be flooded with PM's.
Couldn't you remove the accelerator pedal from the car, protect the rubber pad with a heat sink or wet rag, use a torch to heat it, and then bend the pedal arm downward to restore the difference between the brake and accelerator pedal heights?
Rustjunkey

[John Brennan]

Russ of Rapido used to talk about how the accelerator cable stretches over time...

[DSPXR4ti]

Or just make the cable shorter, ACE hardware has the hardware to shorten cables, I'm going to try this for this weekend after I put in the clutch.

Ben

[Ray]

joe, looking at the pictures (cant do video here) my first concern would be shear loading on the bolt. simple mod tho. nice work.

[hEaT]

Joe,
Cute foot! Hopefully none of the forum members have a foot fetish or you may be flooded with PM's.
Couldn't you remove the accelerator pedal from the car, protect the rubber pad with a heat sink or wet rag, use a torch to heat it, and then bend the pedal arm downward to restore the difference between the brake and accelerator pedal heights?
Rustjunkey

Haha yeah, definitely how I don't want to spend my morning at work
That would certainly be possible, but I like the new position better than the old one so not a concern at this moment.

Russ of Rapido used to talk about how the accelerator cable stretches over time...

I would not be surprised at all. The cable under the sheath looks brand new, but it would be nearly impossible to see the stretch by just looking at it. Maybe we could get Blugg to compare some used cables and see if there is any difference in their lengths?

joe, looking at the pictures (cant do video here) my first concern would be shear loading on the bolt. simple mod tho. nice work.

Thanks. It seems the load is in-line with the bolt. I pulled the bolt completely and let it hang free and drove the car. It didn't bind and it had the same effect. If the bolt does snap, I wouldn't be too worried. I just didn't want to run it that way all the time in case is does bind up on me.

[Rustjunkey]

Also if shearing proved to be a problem couldn't you run the bolt through a thicker collar of the proper length thus spreading the force on a larger area of the bracket lessening the shear force on the bolt?
I agree with the others it is an simple mod and simple is best!
Rustjunkey

[hEaT]

Definitely a possibility. There is also room to run a much larger bolt through there if it proves to be a problem.

If anyone is thinking of doing this, remember that the spring on the TB closest to the passenger side is also disconnected. It's still on the shaft, but not hooked to anything to provide resistance.