Where'd Everybody Get Their Spare/Replacement Skunk2 TB Return Springs?
 

So after breaking my Skunk2 throttle cable bracket and having to get it welded at the last track event I went to, I decided I should stock up on more spares for common failure points. A spare throttle return spring for my throttle body was next on the list. I hit up Skunk2 who were unsurprisingly no help at all.

https://cimg0.ibsrv.net/gimg/www.mia...d9ac88fd7b.jpg

What a joke. Those of you who have broken S2 throttle return springs, what did you use as a replacement?

Seriously!?

There must be a zillion industrial supplies places, hardware stores and the interwebs. Take it off, march into one of those places, contrast and compare springs, and you should be able to find one that is close enough.

What makes you think the S2 springs are a failure issue? I get that a breakage is possible, but are people reporting breakages? My 3 Skunk TBs have been rock solid, but maybe others have had issues that the 'how to prep your S2 for installation' threads/posts don't cover. I won't be rushing out to buy a spare myself, but good luck to you.

They typically ship with zero preload, so the throttle plate doesn't always close completely when closed. You can see this with a standalone, TPS will ready 1-2%, and your idle will be high. Snap it shut from WOT and it'll typically close, but that's not something you can always do. To fix this, you drill holes in the cable cam to increase preload, which puts more stress on the spring.

My guess is with lots of WOT (highest tension), vibration, and heat from racing, and they fail.

I personally have never seen it with the dozen or more that I've installed, but then again I've never seen a stock throttle body fail either.

Yes, I’ve read of a few reported breakages due to the increased preload needed on the throttle return spring to keep the butterfly closed on most of these TBs. Do I have to worry about it? Probably not. But a few bucks for a spare is cheap insurance.

I’m aware of the throttle barrel mod and have done that to my TB already. I ran the TB without the modification out of the box (figured I might as well try it without the extra spring preload first) and immediately started having the throttle stick open at idle once the engine bay got hot.

I currently have a hole drilled in the barrel for higher preload maybe 3-4mm from the original one. My throttle plate no longer sticks open. However, I’ve read about instances of the return spring failing after having the additional preload added to it. Just figured it’d be cheap insurance to carry an extra one to races in case mine suffered the same fate.

Gee, you’re right. I probably didn’t need to make this thread. I just figured maybe someone had firsthand knowledge on a spring that worked and didn't break in the long run. I’ll scope out a couple places for generic return springs. I’m sure plenty, if not most, will fit the bill.

I've heard of it happening. Must have happened enough times that MX5Mania in Australia sells an "upgraded" spring, but yeah, head to a quality hardware store and look for a stronger spring if you're concerned. I can't imagine a throttle stuck open is a pleasant experience,
https://mx5mania.com.au/products/upg...af880bfc&_ss=r

Keeping the preload to the minimum required to fully close the TB is probably the safest route. I have not seen pictures of the holes drilled on TB with failed springs, but I have seen how far from the original some have done and it seemed excessive. I'm with Curly, some have probably going too far and the fatigue at WOT is too much.

As possibly irrelevant anecdata, my zero failure rate my be related to my only using the indicated place to redrill the hole, and in the latest one trying a hole a smidge closer to the stock location. Definitely agree that going overboard in increasing spring tension not a good idea.