Snapped another throttle body - SR20DET - PICS

[lok]

you should put some mesh after the throttle body in case it happens again.

[bloodangels13]

red locktight the screws. I wouldnt weld them considering the shaft is probly treated metal that wont take to the heating that welding will cause. double check the stops and give the cable a hair of slack. If your still having the issue something is seriously wrong

[s14unimog]

Originally Posted by lok

you should put some mesh after the throttle body in case it happens again.

Yeah but then I would have to randomly check this "catch" for a dislodged screw and who knows what that would do to the airflow in the manifold.

Originally Posted by bloodangels13

red locktight the screws. I wouldnt weld them considering the shaft is probly treated metal that wont take to the heating that welding will cause. double check the stops and give the cable a hair of slack. If your still having the issue something is seriously wrong

I hear what you're saying, but it doesn't look as though my tack's had anything to do with the failure; the break isn't associated and happened just as the first one did that wasn't welded. I think "seriously wrong" is a bit excessive...The existing assembly, if adjustment isn't necessary, just requires more support. The next ones will once again be tacked, I'm not risking the motor on loc-tite.

[hsitko]

Guys, guys, guys. This is so simple its silly. You have the full throttle adjustment for your throttle cable too tight. You are pulling the throttle shaft torsionally when you hit full throttle because you have already opened the throttle 100% before your pedal gets to the floor. You need either 2 people or a brick to get your adjustment correct. One person (or brick) to hold the pedal to the floor and one to adjust the throttle cable to "not guitar string tight".

You want just a little bit of slack in the throttle cable when you are at full throttle. You want to open the throttle all the way just not to the point where you have already achieved full throttle and can still press the pedal further. Your cable mounting bracket might not be positioned correctly. It looks like you are already at the end of your adjustment. You do not need a throttle stop. You just need to adjust your cable properly. I GUARANTEE this is why you have broken 2 of them.

[s14unimog]

we shall see. It should get here tomorrow or the next. I'm not adjusting anything until I get it all back together and can figure out what's happening.

I agree with you that this might be the problem but I do recall setting the cable up not to do that. I'll be sure to follow up what happened

[s14unimog]

Okay guys, its obvious what the problem is. After reassembling everything, just as I had it, I noted the pedal stopped, via the stop on the throttle body, about 1/4" off the pedal stop on the floor board; Doh!. Now considering you can't adjust this pedal sweep range, the only clear solution is an extended stop on the floor board (as a few have mentioned). Now my big question....


How many SR's are riding around and using the throttle body stop as the pedal stop? Answer: all of them?

I don't see how it couldn't be the case, unless modified by the engine installer, the 240sx cable and pedal assembly can't be shortened by some adjustment under the dash and considering the diameter of the SR20 pulley, it just pulls too much.

Why has this not come up more?

I'll post some pictures of my findings and fix once I get a stop machined.

[s14unimog]

So here is the stop... This was the easiest/most reliable thing I could come up with. I replaced the back strap for the pedal with a billet piece I machined. I decked the surface until about a 1/16" was left at the throttle stop. I also rewelded the new screws on the throttle body hinge (not interested in taking any chances) and welded up that pressure port on the bottom of the throttle body.

If you're running an SR20 then you should consider looking at your setup. Unless I'm missing something, this should be a problem for everyone.

[codyace]

THat will certainly fix it!

I know I spent quie some time designing a bracket to not require a stopper, but man that looks great! Nice solution

[jspaeth]

Originally Posted by s14unimog

Okay guys, its obvious what the problem is. After reassembling everything, just as I had it, I noted the pedal stopped, via the stop on the throttle body, about 1/4" off the pedal stop on the floor board; Doh!. Now considering you can't adjust this pedal sweep range, the only clear solution is an extended stop on the floor board (as a few have mentioned). Now my big question....


How many SR's are riding around and using the throttle body stop as the pedal stop? Answer: all of them?

I don't see how it couldn't be the case, unless modified by the engine installer, the 240sx cable and pedal assembly can't be shortened by some adjustment under the dash and considering the diameter of the SR20 pulley, it just pulls too much.

Why has this not come up more?

I'll post some pictures of my findings and fix once I get a stop machined.

This is 100% definitely true.

The question to me now, however, is why this would ever cause stress on the THROTTLE SHAFT.......it seems to me that once the throttle pulley hits the stopper, any subsequent pressure put on the pedal only results in additional tension in the cable.

It does not seem that additionally pushing on the pedal imparts any additional stress on the shaft........

Nonetheless, I agree with your assessment.

I basically think that the circumfrence of the SR throttle pulley is smaller than that of the KA.....

Hence, less pedal action is required to fully open the throttle.


The interesting question here would be if someone owns a JDM 240sx could measure the distance between the pedal and the floor stopper in their car. My bet is that the stopper on a JDM 240 sits closer to the pedal.

[NYS13SLIDER]

nice pedal extension, but i think the quicker easier solution would have been to add the piece of billet,or for that matter, any other suitable material as an extension on top of the throttle stop thats already located on the floor and not on the pedal itself. Thats what i plan on doing at least.

[s14unimog]

Originally Posted by codyace

THat will certainly fix it! I know I spent quie some time designing a bracket to not require a stopper, but man that looks great! Nice solution

Thanks! Can you elaborate more on how you prevented over pulling?

Originally Posted by jspaeth

This is 100% definitely true.
The question to me now, however, is why this would ever cause stress on the THROTTLE SHAFT.......it seems to me that once the throttle pulley hits the stopper, any subsequent pressure put on the pedal only results in additional tension in the cable.
It does not seem that additionally pushing on the pedal imparts any additional stress on the shaft........
Nonetheless, I agree with your assessment.
I basically think that the circumfrence of the SR throttle pulley is smaller than that of the KA.....
Hence, less pedal action is required to fully open the throttle.
The interesting question here would be if someone owns a JDM 240sx could measure the distance between the pedal and the floor stopper in their car. My bet is that the stopper on a JDM 240 sits closer to the pedal.

Yeah, I would also love to know this. There has got to be a few Silvia's on here that can comment, although I'm not sure how easily measured that is. I see what you're saying about the shaft and I think that is the case on the stock setup; S13 SR20 with S13 pulley, since its offset more towards the throttle body. Surely the extra moment arm of the S14 pulley has to push it past its breaking point. Also don't forget the stop isn't located on the pulley its closer to the throttle body, so the cable is actually out past that leverage point (reference the first picture in this thread). After installing the piece I ran down a couple nice roads on the way home and noticed how hard I would contact the stop under throttle modulation; its apparent its there.

Originally Posted by NYS13SLIDER

nice pedal extension, but i think the quicker easier solution would have been to add the piece of billet,or for that matter, any other suitable material as an extension on top of the throttle stop thats already located on the floor and not on the pedal itself. Thats what i plan on doing at least.

I originally tried what you are describing but that factory stop is only secured with the one self tapping screw and if you remove the stop you'll see that its not as easy as it looks to mount to. You can't drill into the piece, b/c you'll fu*k up how it mounts and since its so loosely mounted I didn't feel anything I mounted to it would be reliable.

[codyace]

I honestly just made a bunch of brackets until it worked haha. Brick on the pedal to simulate wot on the floor, and then adjusted the stopper and arm and etc etc.

I have NO CLUE why I didn't consider a piece of wood on the factory stop, that would have been easier back then, but it is what it is hehe.

[s14unimog]

oh I see what you're saying, lol. I had to trash a motor to figure mine out...

[TheRealSy90]

Bringing this back from the dead.

Disregard the whole "S14 pulley is the problem" shit. Mine is an S13 pulley.



Now what i'm thinking is the best fix, is actually to not fix it. Simply because the way it is now allows for a bit of flex after the throttle body is at wot. And it still opens and closes just fine. I Can't see how not fixing it will have any ADDITIONAL negative side effects. Thoughts?

[jr_ss]

Besides your throttle plate sliding off center and locking it wide open I see no ill side effects...

[TheRealSy90]

The TPS side of the rod and everything is still very tight fitting, the plate doesn't move around at all from what I could tell when I was messing with it.

[J_SquidYO]

is that the stock manifold??? the realsly90? My buddy went thru 7 throttl bodies before he went q45 and we literally tried everything u guys have said and nothing fixed it he got lucky everytime when he noticed it idliing high because the pulley had pushed itself out and had a vacuum leak

we did stock cable holder and 2 custom ones he had s14 pulley which suck and mine broke with that also and im stock sr with the isis manifold never had a problem with the stock mani he even made it so the throttle only open like 90% and it still broke

he has around 400hp also with an isis manifold and he tried ka TB's Sr TB's and none held it honestly i asking if it was a stock manifold because i think it has to do with the manifold and how u drive your car it seemed to happen to him pretty easily when he would bounce rev limit drifting or playing around and IDK if that is when it has happened with you guys but something else to take into account

we have also tried different pedel stops with no luck he just made a custom plate and cut his manifold and welded the q45 plate onto it so he could bolt it right one and it has held up since

and i had the same problem as the thread starter cyl 1 sucked up the screw "tick tick" removed the head and exact same thing am deffinitaly in torevive this thread and see if anyone has any more updates

['97 S14 SE Turbo]

Originally Posted by TheRealSy90

You really should fix it. See the shiny marks on the butterfly plate around the break? That's from it moving and scraping against the broken shaft. See the unbroken side? That additional signs showing the amount of movement the plate is having. Airflow around a butterfly plate is not smooth, so over time, the rest of the shaft will break, costing you a lot more in repairs.

One thing I've seen regarding the cause behind breaking the pulley shaft is the throttle cable positioning. It should not have ANY side loading when pulling on the pulley. NONE!!! That causes sideloading on the shaft. From what I can see in the pictures of the OP and your picture, there is misalignment of the throttle cable to the pulley. Go look at OEM setup and see how well aligned they actually are. It may look simple, but not keeping it aligned will cause problem.

[s14unimog]

guys I'm telling you, the problem with the pedal pull length. You gotta stop it their. I made that spacer for mine and its been fine ever since. I still weld the backs of my screws to the hinge for the extra security.

[!Zar!]

Adjust the stop.

DONE.

[s14unimog]

^No. It's at the pedal. There is no stop to adjusts. You have to make the pedal responsible for the stop.

[!Zar!]

The stop is located behind the pedal broham.

[stevecorrado88]

I've tried it all. U can say its the pedal stop n I'm sure that could be the case just like all the other examples everyone has said. But what if u tried all them n it still failed like in my case. Like squid said I probly broke 7 tb tryin different things and nothing helped. I even make my throttle open to about 90 percent so it wouldn't pull it father than should. Q45 fixed it all, I can't feel a difference other than have more power top end.

[yellowcr]

try the q throttle body had the same prob

[TheRealSy90]

Originally Posted by '97 S14 SE Turbo

You really should fix it. See the shiny marks on the butterfly plate around the break? That's from it moving and scraping against the broken shaft. See the unbroken side? That additional signs showing the amount of movement the plate is having. Airflow around a butterfly plate is not smooth, so over time, the rest of the shaft will break, costing you a lot more in repairs.

One thing I've seen regarding the cause behind breaking the pulley shaft is the throttle cable positioning. It should not have ANY side loading when pulling on the pulley. NONE!!! That causes sideloading on the shaft. From what I can see in the pictures of the OP and your picture, there is misalignment of the throttle cable to the pulley. Go look at OEM setup and see how well aligned they actually are. It may look simple, but not keeping it aligned will cause problem.

Damn I didn't notice the marks from the butterfly moving around when open until you said something. Yeah i'm definitely going to have to do something about it.

@ J_SquidYO, not a stock manifold. It's a TopSpeed (greddy style).

@ S14Unimog, interested in making another one of the stops like you have?

[s14unimog]

Originally Posted by !Zar!

The stop is located behind the pedal broham.

Where? there isn't one. The cable is crimped just beyond an eyelet and has no way to adjust. At least on my s14.

Originally Posted by TheRealSy90

Yeah i'm definitely going to have to do something about it.

@ S14Unimog, interested in making another one of the stops like you have?

ya think? Na man, I didn't record any dimensions and it only works with the Razo pedals I'm using.

[conrad_s13.5]

ive heard alot about these problems and never saw any examples!

scary shit!

def something to look into before i get my set up running again.
might as well upgrade to a q45/etc anyway right?

[stevecorrado88]

I don't recommend a q45 fb swap unless u have a reason. If your stock tb works than keep it. If your running high hp than its more of a upgrade. The q45 tb have a bracket so the pulley can't really get pulled to the side, to who ever that broke one u must have something really off.