Skunk2 Pro throttle body issues
Posted: Wed Aug 24, 2016 3:42 pm
Just a heads up to all those using or considering using a Skunk2 Pro throttle body on their MX-5
I put a new Skunk2 TB (part # 309-10-0200) in my NB8A race car about 2 years ago, not for performance but because I considered it a good idea to replace the standard TB due to their reputation of falling apart and causing engine damage when used for motor sport with regularly high engine RPMs.
During the 2nd MX-5 Cup race at Wakefield Park a few weeks ago, the throttle cable pulley on my Skunk2 TB became detached from the TB, allowing the throttle return spring and a bush to escape. I later managed to recover the bush but not the return spring. The mostly likely cause was that the nut holding on the pulley worked it's way loose, despite being locktited from the factory.
There were 2 consequences of this failure:
1. With the main return spring gone, and the throttle at maximum at that point, it seems the secondary return spring in the TB was not able to close the butterfly, and the engine was stuck at WOT. Fortunately I was able to shut down the engine and get off the track with no further issues. Damn I hate DNFs!
2. I have contacted Skunk in the USA to obtain a replacement spring. They said that they would try to find a returned TB to disassemble to provide a spring, and after a few follow-ups advised that no suitable TB was available for parts, and so they could not supply the spring.
So, my 3 thoughts are:
1. If you use a Skunk2 Pro TB on your MX-5, add checking of the throttle pulley nut to your periodic maintenance,
2. Consider adding a 3rd external return spring to ensure the TB will close at WOT in case the main spring is broken or lost, and
3. if you are thinking of buying a Skunk2 Pro TB, parts may not be available, so you should factor that into your decision.
For now, I plan to visit a wreckers and try to find a suitable replacement spring. If that doesn't work, does anyone know of any other manufacturers who make MX-5 s TBs which are more reliable for motor sport use than either the stock TB or Skunk2 Pro TB?
I put a new Skunk2 TB (part # 309-10-0200) in my NB8A race car about 2 years ago, not for performance but because I considered it a good idea to replace the standard TB due to their reputation of falling apart and causing engine damage when used for motor sport with regularly high engine RPMs.
During the 2nd MX-5 Cup race at Wakefield Park a few weeks ago, the throttle cable pulley on my Skunk2 TB became detached from the TB, allowing the throttle return spring and a bush to escape. I later managed to recover the bush but not the return spring. The mostly likely cause was that the nut holding on the pulley worked it's way loose, despite being locktited from the factory.
There were 2 consequences of this failure:
1. With the main return spring gone, and the throttle at maximum at that point, it seems the secondary return spring in the TB was not able to close the butterfly, and the engine was stuck at WOT. Fortunately I was able to shut down the engine and get off the track with no further issues. Damn I hate DNFs!
2. I have contacted Skunk in the USA to obtain a replacement spring. They said that they would try to find a returned TB to disassemble to provide a spring, and after a few follow-ups advised that no suitable TB was available for parts, and so they could not supply the spring.
So, my 3 thoughts are:
1. If you use a Skunk2 Pro TB on your MX-5, add checking of the throttle pulley nut to your periodic maintenance,
2. Consider adding a 3rd external return spring to ensure the TB will close at WOT in case the main spring is broken or lost, and
3. if you are thinking of buying a Skunk2 Pro TB, parts may not be available, so you should factor that into your decision.
For now, I plan to visit a wreckers and try to find a suitable replacement spring. If that doesn't work, does anyone know of any other manufacturers who make MX-5 s TBs which are more reliable for motor sport use than either the stock TB or Skunk2 Pro TB?
to remove the twisting that breaks them so I hopefully will not have any more TB problems.
. Found another yesterday, that makes at least three, the screw is gone, hopefully without trace. 