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I've got a waste gate and I wanna use it! - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums - Official Lotus Community Partner Jump to content


I've got a waste gate and I wanna use it!

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Hello all,


Just wanted to pass something to the experts on this-here four thing.


I took delivery - today - of a nice chrome waist gate thing.

IT came without the 'arm' bit which I thought was a bit odd but- hey- I'll recycle mine.


So I .....


pulled off rubber pipe to bottom of rusty old WG

surprisingly  removed 2 very crusty and rusted buts 

wiggled the arm off the sticky out bit (sorry for the lack of technical words) 

Then got surprised that there was no pin or similar holding the arm onto the sticking out thing


Then I took it to the floor and measured lengths and stuff


Disaster one - when trying to unbolt the waist gate from the arm I was getting somewhere (through a ton of rust) and it suddenly went really easy.  Hooray - I thought until I looked down to see I'd sheered off the dame bolt - better still, I sheered it off about 2 mm from the adjustment bit (if you can see what I mean),


So- much use of one of those locking wrenches on 2mm of thread eventually rounded the area.  Tried heating it up on the oven etc etc so then tried the dremmel to cut some of the arm part to expose the bolt but each time it just snapped off.  Eventually I got to a bit where there was no nut inside - so I had effectively shortened the arm - but it worked so no complaints there.


I attached the new waist gate to the old arm and used approximate length of the one I took off.


So then I want to fit it.


I got the 2 bolts to hold the main part in place


I then realised that the only way to connect the arm is for the arm to match the hole up to the position of the sticking out thing on the car.


So weird question 1)

Why measure up the length of the arm if it has to fit on something that's static on rest?  If it was longer the thing would not 'marry up' - if it was shorter then you'd have to move the mechanism on the car to fore it into the hole - so I simply adjusted the length so it would marry up and sit comfortable on the sticking out bit..... what I have done ok and how could you make adjustments where the thing your placing the hole in the arm over is static at 'rest point'.  To me it was "bolt on the business end with the two bolts and adjust length of arm so it would fit over the lever thing.



Here comes question 2.


I then went to plumb in the black pipe removed from the old crusty waist gate.  Except there was a design issue related to putting it back together.  The old unit had the pipe connection on the side of the unit whereas this new one has the equivalent pipe connection at the rear/back of the item.

Needless to say the pipe would not stretch to the new position.  Dammit! 

So after a bit of stretching and looking round the house for pipes I decided to disconnect the sensor from the pipe from the opposite side of the boot wall (making it suspend safely away from heat etc.  Then it could be hooked up.


As I had completely run out of sunshine I decided to call it a day - put the tools and bit in the boot lock it all up etc etc.


I will finish the car off tomorrow (Wednesday).


So what I'm after (please) is the first question (seemingly non-required adjusting of the unit due to the fixed nature of the things it connects to.and also if anyone else has had the same issue regarding placement of what looks like  breather pipe to the back of the WG - and how they got around it.


As always I appreciate your comments and advice.....

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You will need some new hose to connect to your wastegate, there is a guide on how to set it up on lew have a read of that it will tell you all you need to know. There are further posts on this forum where other people have fiddled with it do a search and you will find some good reading and be sure you have it set ok before you go for a drive if its set miles out you could do some serious damage. 

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Thanks - that link is very interesting - plus I'll do a search on the forum.


Having read the article I can use correct terminology now......


So - when I put the new wastegate in, the adjustment arm seems irrelevant as the hole that meets the flap valve is fixed. So when I adjusted the length of the arm I did it in such a way that the hole in the arm fits over the flap valve stub with the flap valve in the 'rested' position.


The only thing I can think of is that you need to move the flap valve stub to meet the wastegate arm thereby internally allowing the flap to open slightly in it's 'rested' state.


As it happens I had to make the arm longer to get it to fit over the flap valve - so the only risk would be underboost (ie making the arm longer than I previously thought it should be from measuring the old unit).

Fortunately the S4s has a boost meter so - even if it's approximate - I have some idea of how correctly I've fitted it (ie - if it goes up to half way at max boost then I know that the arm is too long).


As far as the rubber pipe is concerned I realise that I've written my explanation (above post) in quite a nonreadable way!


Basically - to make it reach I've taken the connection on the engine/boot wall (engine side) and removed the nut holding it on thereby allowing it to 'hang' freely. With the rubber hose end connected to the capsule, the connection that is 'hanging' actually sits safely between connections.  I suspect that the 'hanging' connection thing is a sensor for the ECU.  I guess I can buy a piece of pipe in the future but in its current position its actually held quite nicely away from any hot or moving parts.

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  • Gold FFM

The way he's put it on, his problem will be underboost!

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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The way he's put it on, his problem will be underboost!


I'm going with this response.

I had measured the distance between capsule and end-of-arm and - as I said - the hole did not reach the flap arm, and reading other threads - the longer the distance the lower the boost - shorten the length for more boost.  Thus the only eventuality of this would be under boost.


There is also the other thing - opinions of me blowing up my engine- i.e. a bit like driving a car with a cold engine - I won't start the engine and floor the damn thing right off the driveway.  For 2 reasons:1)  it's bloody stupid and  2) The chap opposite me would not be impressed with his BMW being about 2 ft shorter.  Being realistic don't you think I'd be driving it as if I'm running something in?

Also - Like others here, Taff has said this is an easy DIY job - which it is.  Well apart from the fact that the old unit was totally rusted including within the arm - blimey it took a whole load of time separating the old waist gate mechanism from the arm piece.


Now, extending the subject somewhat, how can the setting be anything other than the flap in the rest position?  To be otherwise would mean lifting the the flap arm to meet the hole on the arm.  Perhaps that's what needs to be done, but it 'feels' counterintuitive - i.e. the flap being slightly open when the foot is not on the accelerator.



Test drive in 20 minutes!


(if the starting issue doesn't rear it's ugly head).


If you see a bright glow from the south east accompanied with a hefty 'boom' then you'll know what/who it is.

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Got in to the car

Started it [started it?] yup - started it

Drove down the hill stopping after 200 yds to push the engine to do something (rather than coast)

Got on to main road - warming the engine up.

I took the revs up gently and saw the needle move which was a relief


So then - when the engine was warm - I gently pushed further and further on the pedal 


Oh yes - VERY nice...  it got to halfway up the dial (whereas before it went 1/3rd) and it's already a lot more fun.

Gave it a good test run with emphasis on triggering turbo-time


So - the conclusion - it's all working great however I need to turn the arm  half-a-turn clockwise and do another test run.  Repeat until 1 bar is found.


I feel quite happy that after the effort it's all working back there, albeit in need of a 'tune'.


One thing though (and this has always happened esp when cold) - If you drive the car like a granny drives a Morris minor it really disapproves.  As you get up to 3k revs gently and slowly it gets a bit jerky around that rev/min.  Do it quickly and it's not noticeable.  Floor the bastard and it just pulls and pulls.


Do others have jerkiness at mid revs driving at Tesco carpark speed?

Edited by Stimpy
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Not really certain why it went away since the crank up is new, 107 cam, green dot pulleys, s4s + WC chip, alunox headers, RC injectors, ported and relieved head, bigger but unknown turbo installed. But it is gone. Boost comes on around 2500 and just builds up to 1.2 bar on an AEM digital gauge if I hold my foot on it and does not drop off until I let go of the pedal or run out of rpm room although I have not tried this in 5th. New tires so am being gentle as they are very very sticky right now and do not want to break an axle or primary shaft. Only 1000 miles on it so am letting it settle in by only doing one of these runs once in a while right now. Wish I could be more direct in my answer. It does however buck while cruising once in a while when letting off the gas slightly but that is at 70-80 mph or so and think that is the cam causing this. One thing that has changed from the original car is now 1st lasts about 2 seconds to 7000 rpm from a 3 mph rolling start. Actually quite scary as I have to pay much attention to keep from running out of range.

Edited by MikieP
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Want to go to larger exhaust turbo back and de-cat it and let it relearn herself to a higher output but out of money for now. one additional comment about the cam, it does idle quite lumpily (sic) and am not certain if the grind is really completely stock 107 - the crank, head work and cam were prepared by a lotus racer. So much quicker than before the rebuild. Running at 110 mph seems effortless now, where there was noticeable strain before. But it does make more exhaust noise now. Bless the Alunox header. It now sounds like it looks. lol.


If I don't blow her up i will be amazed. :scooter:

Edited by MikieP
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That's had some enthusiastic tuning - no wonder it runs so sweet.


Ah well - at least the 3k stuff is a known thing.


Going out now to turn a few things and waste a bit of petrol


(if it starts)

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I can't work out certain elements of what the waist gate settings are.


I'll show some examples but although I find the 'take the piss' stuff funny myself, on this it would be nice to have some sort of explanation to a person (me) who is asking for advice from people who know much more than I do from experience (for the moment - I'm learning fast) so - here goes....


I took the car out yesterday after fitting the waist gate unit.  I got 0.5 bar, half of what I should get (and I know that the boost gauge is not a scientifically accurate thing but at least its a guide).


So today I shortened the length and went out for a drive.


I still get 0.5 bar.


When setting it further in, I realise that the arm was at the shortest it would go (any further and the hole would not line up with the 'lever'.  Again - 0.5 bar (maybe a tiny bit more).


So I decided to do a 'reverse experiment' and lengthened the rod to satisfy that the boost would go down.  Well, it was long enough for the pressure gauge to do nothing at all.


So what mystifies me is how can I make the arm shorter when the pivot arm is fully down (i.e. at rest).  If I shorten the length of the arm more the hole does not go over the lever.  I realise the lever, without the arm, sits at its furthermost down - if that makes any sense.  i.e. when you hold the lever with your fingers you can swing it clockwise and back and hear the internals clink to a fully closed position.


And if making the rod longer causes less boost then how does that happen? Doesn't the waist gate push the lever?  If the rod is made longer then surely the lever swings further.


A further puzzle is this... the lever to which the arm connects can be rotated clockwise at its extreme - since the waistegate presumably pushes and is fixed to it's mount then it will only be able to push as far as the lever can go horizontally.


What am I missing here?  

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this pretty much explains it - i didn't realise you could pull on the rod and lift it over the flap lever.  so this is called 'pre-load'


What was the coolant temp?

erm, 'normal'  it tends to hang around the 1/4 to half mark


pray why?

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Ignore the temp gauge, ours reads about 15degrees under, when 'normal'. 

Do your fans come on? When they come on, check the temp gauge, this will then give you an idea of how far out it is reading.


Of course your 'stat might be stuck open seeing as the car has been stood for a long time......

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