Snapped another throttle body - SR20DET - PICS

[mct3351]

Your throttle pulley is on wrong. Placing the cable out that far is likely putting excessive bending forces in the axle when its resting on the stop.

I'd consider flipping it or making a pedal stop.

[superJoy]

Originally Posted by mct3351

Your throttle pulley is on wrong. Placing the cable out that far is likely putting excessive bending forces in the axle when its resting on the stop.

I'd consider flipping it or making a pedal stop.

WHAT HE SAID.

You have that pulley on backwards dude. I don't have an SR but on all the Nissan engine's I've dealt with, that pulley goes on the other way so the cable is closer to the TB itself. It's sticking out quite a bit farther than it should.

You're prob putting the shaft in bending whenever it hits the stop, and you're moving that lever arm out by installing the pulley wrong, which causes the shaft to fail since it wasn't design for that amount of stress.

I don't think the cable bracket yall talkin bout makes that big of a difference.

[s14unimog]

Originally Posted by superJoy

WHAT HE SAID.
You have that pulley on backwards dude. I don't have an SR but on all the Nissan engine's I've dealt with, that pulley goes on the other way so the cable is closer to the TB itself. It's sticking out quite a bit farther than it should.
You're prob putting the shaft in bending whenever it hits the stop, and you're moving that lever arm out by installing the pulley wrong, which causes the shaft to fail since it wasn't design for that amount of stress.
I don't think the cable bracket yall talkin bout makes that big of a difference.

Are you two both blind...? You can't flip it over. If you do that there isn't a place for the cable to guide. There is only one single way to install it...

[mct3351]

Well then that pulley wont work. If you were to compare the length of the moment arm of the s13 pulley on the s13 throttle body, with the length of the moment arm of an s14 pulley (installed backwards from the way its installed on an s14 throttle body) installed on an s13 throttle body, the way you have it, its about 4 times longer and the bending loads are 4 times more.

Since I'm blind and cant see that this is the only configurstion that will work the easiest thing to do, is make a pedal stop. This will limit the force pulling/bending on the end of the axle once its fully rotated and resting on its stop.

Or you can disregard my advise and do nothing and keep hoping for a different result.

[Couped_up'd]

Originally Posted by mct3351

or you can disregard my advise and do nothing and keep hoping for a different result.

ziiiinnnnggg

[s14unimog]

Originally Posted by mct3351

Well then that pulley wont work. If you were to compare the length of the moment arm of the s13 pulley on the s13 throttle body, with the length of the moment arm of an s14 pulley (installed backwards from the way its installed on an s14 throttle body) installed on an s13 throttle body, the way you have it, its about 4 times longer and the bending loads are 4 times more.

Since I'm blind and cant see that this is the only configurstion that will work the easiest thing to do, is make a pedal stop. This will limit the force pulling/bending on the end of the axle once its fully rotated and resting on its stop.

Or you can disregard my advise and do nothing and keep hoping for a different result.

You haven't looked at an S14 SR in a minute. It is installed just as I have it on my S13 SR throttle body. I don't think the moment arm is actually any different.

Originally Posted by lok

"Insanity is doing the same thing over and over again but expecting different results." I am guessing you have already tried moving the mounting point for the throttle cable?

Obviously, and I don't plan to just re-install as without some alteration. I have not move the pull point yet. If you look at the first picture, its pretty nicely lined up. I really think I'm either over pulling the cable a few thousands or the S14 throttle body has some differences


Anybody have any pictures of an S14 SR throttle body?

[mct3351]

You are right about how the s14 pulley is installed on an s14 throttle body but the pulley sits closer to the throttle body on the s14 than the s13. See the "free body diagram" for clarification on what I mean by bending. The throttle cable pull is much closer to the throttle body on both the s13 and s14 from the factory than what your working with. The yellow shows an exageration of how the axle is bending once the stop is reached. The OEM s13 pulley is deeply concave to move the pulling action closer to the throttle body.

[s14unimog]

Originally Posted by mct3351

You are right about how the s14 pulley is installed on an s14 throttle body but the pulley sits closer to the throttle body on the s14 than the s13. See the "free body diagram" for clarification on what I mean by bending. The throttle cable pull is much closer to the throttle body on both the s13 and s14 from the factory than what your working with. The yellow shows an exageration of how the axle is bending once the stop is reached. The OEM s13 pulley is deeply concave to move the pulling action closer to the throttle body.picture

I'm not denying that the S14 pulley, installed on an S13 throttle body, doesn't increases the leverage advantage on the center shaft, I even brought that up myself when responding to Def. What I am trying to illustrate that there is more to just slapping on an S14 pulley to cure the cable alignment issues with a GReddy style manifold. And more recently to discount those who think I've got it installed incorrectly.

The main objective behind this thread is to bring to light the problems with this commonly recognized quick solution for the GReddy style manifold. Thanks for the illustration, and I'm quite aware of what you are describing, but like I said, this is/has been a common solution for this manifold. Apparently more support is needed for this assembly.

My new throttle body will be here in a few days. I'll get some real numbers and see if its an adjustment issue or if more support is needed. I think the pulley is a great solution but might require additional support.