Quote:
Originally Posted by pixlpush
I had the tips of my old style Larini SE exhaust tack welded in place because I couldn't keep them in place. The new ones are one piece. What about having the cat -> exhaust joint tack welded? Seems like it might solve the issue of the joint coming loose, what do you guys think?
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Two issues are at work, both can cause a fire. 1) Cracked cat weld which eventually fails and muffler separates from cat with clamp in place and 2) clamp failures at slip joint -- Lotus specifies that the muffler clamp is a
one-time use item
Recent Lotus TSB on the subject:
BULLETIN..... Model: Elise/Exige/Europa/2-Eleven
TITLE: Precautions when re-fitting exhaust muffler on any Europa or Toyota powertrain Elise/Exige/2-Eleven.
REASON: To ensure adequate sealing and security. The slip joint between the catalytic converter outlet 'U' bend and the exhaust muffler is secured by a strap clamp and pinch bolt. This clamp is designed to apply the correct clamping force to the pipe when the pinch bolt is tightened to the specified torque of 54 Nm.
In order to guarantee this result, the clamp is for one use only, as some stretching and settling of components will occur in service. Be aware that the security of this joint is essential to ensure the integrity of the exhaust system, in respect of emissions, noise, heat release and safety. Extreme temperature gradients and powertrain shunt (especially with track use), will subject the joint to additional stress, and for cars
used on closed circuits or in similar conditions, the Pre-Track Use Check List, LSL520 should be followed, which includes an operation to check the exhaust system for sealing and security.
ACTION: If an exhaust muffler is at any time removed or replaced, the following points should be observed:
1. Ensure that the clamp (A120S6000S or B116S6001H) is renewed, if necessary cutting the tack weld (used only to assist factory build) with a precision rotary tool to remove an old clamp from a muffler which is to be re-fitted.
2. Position the new clamp to be flush with the end of the muffler pipe, and orientated with the clamp split equidistant from the two patented joggled seal slots in the pipe. Tack welding the new clamp is not necessary.
Note that all new standard fitment mufflers, and Lotus accessory sports mufflers LOTAC05334, LOTAC05335 and LOTAC05450, are supplied with new clamps tack welded in position. Elise S sports exhaust LOTAC05391 will require a new clamp, A120S6000S, to be ordered separately.
3. Dependent on model, be aware that the optimum position of the muffler may not be determinable without trial fitment of the diffuser in order to centralise the tailpipe(s) in the diffuser aperture (note: access to the clamp is not available with the diffuser fitted). In this situation, the clamp bolt should be only nipped up for the position assessment, prior to torque tightening on final assembly. Achieve the maximum possible engagement of the 'U' bend pipe into the muffler inlet, consistent with acceptable tailpipe position. Assemble the joint dry.
4. Finally, torque tighten the clamp bolt to 54 Nm. From this point onwards, the clamp should be discarded if the clamp bolt is slackened.
5. Manually attempt to slide or rotate the joint. No movement should be possible.