Faulty turbo boost logic?

[philip5]

Is my thinking correct?
1)Previous owner screws with the rod in the wastegate by turning it.
2)Boost doesn't always fully develope properly, but(this is a BIG but)you pull that vaccuum line from the over boost relay, and the thing screams.

Is it right, based on the above, to conclude that the wastegate is ALWAYS allowing way too much boost?
If the wastegate were not, why would I experience increased boost everytime the over boost relay was disconnected; isn't it there "just in case" excess boost is developed?

Thanks, by the way, I need new shocks (left rear is frozen) any recs from you guys? I've heard Konis are best but must be removed to adjust. Annother guy says go with Spax (?).
Philip

[cnh1990]

Do not ever turn the rod, only the adjustment nut. If you turn the rod you will break the diaphram in the wastegate capsule.

I'm not sure what vac line you are talking about but it maybe the line going to wastegate caplue itself. If it is that one you do not have a functioning wastegate.

How are you with working on cars?
I can give you instructions on how to test the wastegate and to adjust the rod if you like?

Koni's need to unbolted to adjust, the Spax a screwdriver in the slot and turn to adjust.

Calvin

[philip5]

Calvin, thanks for the quick reply. Two things; first you didn't tell me which shock do most Lotus owners seem to prefer? 2) I'm pretty handy and would appreciate your instructions.
Thanks again

[grungex]

If the wastegate were not, why would I experience increased boost everytime the over boost relay was disconnected; isn't it there "just in case" excess boost is developed?

Absolutely not1, it is there to allow more boost when the ECM decides it is appropriate. It is not an overboost relay at all, it is a boost control solenoid, and disconnecting it prevents the wastegate from actuating at all. Please read my previous reply to you on this subject, www.pistonheads.com/gassing/topic.asp?t=31092&f=17&h=0

Cheers,
Sanj

[cnh1990]

To set the correct rod adjustment use a 10lbs. pressure gauge and the lumbar seat pump. Apply exactly 8.6lbs./sq. in. when the wastegate arm moves .38mm it is correct. If not move the nut in or out till you achieve this specification. Do not allow the rod itself to spin or you will tear the capsule diaphram. Do not allow this to happen or you will be sorry.
Calvin

[Mark91SE]

cnh1990 said: To set the correct rod adjustment use a 10lbs. pressure gauge and the lumbar seat pump. Apply exactly 8.6lbs./sq. in. when the wastegate arm moves .38mm it is correct. If not move the nut in or out till you achieve this specification. Do not allow the rod itself to spin or you will tear the capsule diaphram. Do not allow this to happen or you will be sorry.
Calvin

To add to Calvin's post, here's a pic of that proceedure I did on mine.

www.voicecrystal.com/Esprit/Wastegate/PressureCalibration10sm.jpg

Actually, the reason I hooked up the guage there, instead of at the input to the wastegate canister, was so I could flip the guage around facing the cabin and have a passenger call out readings to me while I verified accuracy of my dash boost guage.

Also, once you make an adjustment, you can test the max boost you've set it to, 'without' having the ECU interfere, by removing the connector to that solenoid (NOT the vacuum lines!). When you do this, and go for a drive, you should see a real consistant maximum boost of .65 bar (for an SE). There is supposed to be a peak boost in 4th gear that we should be accomodating too. When I tested mine at first, it only went to .55 bar in lower gears, yet I was suspecting I was getting overboost... so I'm still playing with it.

Oh and BTW Calvin, I dunno about your lumbar support bulb, but I was squeazin' that thing like crazy and could only muster about 7psi from it . Maybe it's lack of excercise. But, that is what Lotus suggests to do. I ended up using an air compressor set to very very low (10psi) and was real careful.
Also, .38mm is like .015 inches. That's like just barely moving. Easy to miss with the naked eye. It's a touchy one to calibrate without one of those depth caliper type guage tools used by machinists (I forget what they're called).

As a matter of fact, tonight I just tweaked the rod 1/2 turn looser. Going out for another run to test.

Finally, the rod should be a bit tight on the butterfly spindle. If not, it will make a rattley sound while you drive and will undoubtedly be giving you too low a boost.
Just some observations.

- Mark