Help, second opinion on broken bypass valve

[Doghouse]

I was driving my 07 Exige S in a spirited manner this past Sunday and towards the end of the day the boost / supercharger went totally flat. (i.e. no kick in the pants boost). Just prior to my noticing the drop in power, there was a high pitched metallic whine when I was on the fuel peddle hard. The guy behind me said he saw a puff of black smoke and then a puff of white smoke when I down shifted (happened only once). There was a puff of white smoke after pulling over and restarting the engine.

No check engine lights, oil was clear and not milky and at the proper level. Anyway, I was able to cruise home (two and half hours) but the car did not have the kick in the pants acceleration typical of the Exige S.

Took the car first thing into the local Lotus dealership and they said the bypass valve was likely stuck open and thus no boost.

My speculation is that when the bypass valve got stuck open a rich A/F mixture was sent to the cylinders, thus the black smoke. This was followed by some oil blow by (thus the white smoke).


Does any of this make sense? From the posts I've gone through it seems reasonable, but...

The reason I'm asking is that I have another spirited driving weekend coming up and would like to have the car up and running 100%. They said the replacement part was in North America, so they should have it in a day or two and installed soon thereafter.

As for warranty, well if it's covered cool, if not I can live with that being the costs of driving the car in a spirited manner and enjoying the Gotham 265 reflash.

Would there be any harm caused by driving with the bypass valve in the open position all the time (beyond the total lack of boost, of course)?

Thoughts? suggestions? comments?

[Doghouse]

So the Lotus service tech determined it was not the by-pass valve and now thinks it is the supercharger that is bad.

I have the Gotham 265 tune, but it's hard to imagine that creating a problem with the supercharger. Based on what limited understanding I have, all that does is tweak the f/a mixture and timing and has nothing to do with the performance of the supercharger.

As for warranty covering the work, we'll just have to see what happens.

Thoughts, comments?

[Rugbyduck]

Keep everything you own crossed...

[EricH]

Tune would not effect supercharger reliability assuming you were not backfiring all the time (and you would know it if you were)! Good luck, I guess the dealer can try to pin it on the tune but it really has no effect on the physical blower. That is almost the same as saying the tune caused your horn to quit working.

[Noel]

Please keep us posted. I'll like to know what the official failure findings are.

Also, if you can change the title to reflect that you have a supercharger failure + Gotham tune, it will generate alot more interest and possibly more technical feedback.

Not good to know at all.

[kestrel74]

Bring it over here, we'll work on it ( a second opinion ) ( Hope ya get it straightened out ! )

[Doghouse]

This is a further update from an earlier post regarding a dead by-pass valve


Help, second opinion on broken bypass valve

To summarize the facts, I was driving this weekend and downshifting from 4th to 3rd for a turn-in, upon application of the fuel peddle there was no boost. The guy behind me said there was a puff of black followed by a puff of white smoke. After stopping and restarting there was a further puff of white smoke out of the tail pipe, but no further smoke. No check engine lights, no codes thrown, etc... simply no boost. Engine ran just fine for the drive home 2 hours.

Lotus service tech has confirmed the engine itself is running solid, just no boost.

A bad by-pass valve was suspected, but Lotus tech has ruled that out.

As of this afternoon the Lotus service tech had removed my supercharger and there is a heavy / thick green oil coating out on to the ends of the rotor lobes. (i.e. you wipe them clean, rotate by hand and a thick green oil coats the ends.) The diagnosis at this point is that one of the rotor bearing seals is compromised. He'll have it apart early next week to confirm.

q1) Does this seem like a reasonable diagnosis?
q2) Has anyone else had a similar problem?
q3) Should this be a replace the supercharger situation?
q4) Can the supercharger be rebuilt (i.e. the seal replaced)?

As for warranty covereage, well that's still to be determined.

It's hard to imagine that a Moroso oil pan and the Gotham 265 tune has anything to do with a bad bearing seal in a supercharger.

Thoughts?

Comments?

[jim-clayton]

The SC is a mechanical part. It just spins with the engine. Not a tune issue.

Should be warranty for sure.

[EricH]

I understand you are very worried, but as many have said this should be covered under warranty. Nothing you have said so far would make me think otherwise.