SE Closed loop conversion. Better Economy?

[BFG in the BRG]

Well, bit of an update...on the fuel economy,
pre closed loop.....

constant 291 mile 70/80 mph run I got 36 mpg
251miles A/B roads with occasional hoon 27mpg

Having taken the BRG out of mothballs from the winter - I have finally got round to going for a spin

Bottom line is I now got 40mpg - this was based on a number of fairly long drives with the very occasional full throttle overtake manouver - but a good mix of Motorway, Dual Carriage way, A and B road - 375 miles.

So I would say it's possibly gone from around 30 ish mpg to 40mpg. and it's chipped.... - now all I need is for the exhaust to blow so I can get a Piper.....

[DavidEJM]

- now all I need is for the exhaust to blow so I can get a Piper.....

Hole it with a screwdriver - accidentally of course!

[Bolsom]

I reckon I'm getting about 38MPG with varied driving and today it sailed through the control technique (MOT). I justified the Everest for this
as it failed two years ago on emissions and cost a lot to get through eventually. The MOT lasts 2 years here.

Colin

[BFG in the BRG]

Excellent news

I justified my Everest on fuel economy

Faster acceleration and it pays for itself

[ashm]

I've been trying to remove the manifold blanking plug on my new SE for some weeks... penetrating oil and heat didn't seem to be helping so yesterday I took the 2ft breaker bar to it, and:

IMAG0001 (Small).jpg

Hmm... what now?
Adam

[Jackonicko]

Beer?

[Alan_C]

Drill it out and re-tap? At least access should be easy. And the swarf will go down into the exhaust and shouldn't really harm anything? Though once tapped, you could tape a smaller hose to the vacuum cleaner that'll go into the lambda hole and suck any bits out?

[ashm]

Drill it out and re-tap?

That's what I'm thinking. Hey ho, will have to go get myself a suitable tap. I've got a nice set of cobalt drill bits that make short work of almost anything, but I suspect this job has more surprises for me yet.

Incidentally, this is a good example of a torsional failure of ductile material - the failure plane is perpendicular to the axis of the plug, indicating a shear limited scenario. A harder & more brittle material would likely have been tensile limited and fail along a helical surface at 45 degrees to this plane. The lack of beach marks and the smooth whirl shape across almost the whole plane indicate that crack propagation probably wasn't fatigue related; the torque required to unscrew the thread simply exceeded the torsional strength of the plug. Moral: anti-seize is a good idea.

Maybe the plug was quite ductile in the first place, or maybe two decades of temperature cycling (not to mention my extraction efforts!) have annealed it. At least it shouldn't be too tough to drill out.

On the other hand, anyone got a spare wastegate manifold?

Adam

[tigerdog]

I don't think there's another automotive site in the entire universe where one of the contributing members would post a picture like that then proceed to educate the rest of us on the difference between torsional and tensile fractures! God I love this place!!!! Thanks, Adam!

[John_W]

Doug,
I must respectfully submit that you missed the main point.

It's common in everyday life to hear people (newsreaders etc) confuse the terms stress and strain and use them almost synonymously. In this case torsion is the stress applied and brittle failure the strain suffered by the material. I think Adam was providing a useful illustration of the signatures which show the difference between ductile and brittle failure, with a handy comment on absence of fatigue cracks.

Or was the main point that he probably used too long a breaker bar?

John

PS: my solution would be to stay open loop.

[GeoffSmith]

Hey ho, will have to go get myself a suitable tap.

If you're stuck, I know someone who borrowed a tap off a friend who then loaned it to me when I was changing my O2 sensor. Unfortunately, I sent it back to him but I could be seeing him in a couple of weeks......

[ashm]

Hey ho, will have to go get myself a suitable tap.

If you're stuck, I know someone who borrowed a tap off a friend who then loaned it to me when I was changing my O2 sensor. Unfortunately, I sent it back to him but I could be seeing him in a couple of weeks......

Hmm... I might chase you up on that, decent quality taps are pricey above about 12mm. Won't be for a while though, I'm off on a work trip for a while from Friday and in any case I'll probably declare this an "on the bench" job and try to sniff out another manifold to swap it with. I can even port the wastegate while I'm in there perhaps.

PS: my solution would be to stay open loop.

Well, that would probably be the sensible option, it's true!

Adam

[DeeAitch]

If you're stuck, I know someone who borrowed a tap off a friend who then loaned it to me when I was changing my O2 sensor. Unfortunately, I sent it back to him but I could be seeing him in a couple of weeks......

I think I also know that man and see him everyday

If it was me I'd probably drill and tap the bung something like M8 or 10, insert a bolt - one that is not rock hard in case that also breaks - and see if it would wind the bung into the manifold. These things sometimes have the last thread or 2 exposed to the exhaust gas so get well covered in crud. I was well surprised when mine came out in one piece.
Winding it in and then a bit of back and forth might loosen it up enough to come out without a fight.

[Candles]

If you are totally stuck I have 2 spare BCBs (big cast b4stards) which wouldn't take too long to swap in. You could borrow one, free the O2 sensor, fit it and send me back the other if you like. A bit heavy for the post so some sort of LEC courier would be in order. I'm near Grantham. Pm me if you want one.

Candles.

[niall]

Adam,
Bad luck. I assume that as you mentioned only heat, you did not cool the plug with ice or dry ice!
I am planning to do this job some day and am interested to follow your progress.
I look forward to the next instalment.

[Alan_C]

I think luck has a big part to play with getting these bungs out. Mine was tight, really tight. My breaker bar is 4 feet long, and boy was I pulling at that! The bung finally started to shift and was very tight all the way out, but it didn't sheer. The threads in the manifold weren't too buggered once it was out and the lambda screwed in though a bit tight. I've now changed to a stiffy (to which I welded a lambda boss), so somewhere is the BCB, should be in my lockup.....somewhere.

[rip]

I soaked mine with penetrating oil 3-4 times a week for a month before removing it.
It came out with no damage. Maybe I was lucky??

[pjw12]

Im seriously considering doing this to the pealing pac blue, she rarely gets 250 out of a tank.
currently running an everest and peco and getting alot of 'rally car' burble and popping on over run, which when i was 18 would have been 'cool', but now im not so sure. Would going closed loop get rid of some of this?

Also is there any more power to be had with the closed loop system?

[Enright]

In theory, running the engine more efficiently SHOULD give more power and/or economy at the expense of pops & bangs of unburnt fuel, but in practise I'd say no - you won't notice any more power and pops & bangs will still happen. However your economy should dramatically improve. I believe that this is because the closed loop map is only operational under idling or normal driving conditions. When hammering it the O2 input is ignored, so you get maximum enrichment when you most need it. Then when you come off the throttle there can still be unburnt fuel which catches light in the exhaust.

[pjw12]

That was my theory too, but thought in practice it might be different. Might have a nose underneath in a couple of weeks and check the system out for leaks. might think of adding a silencer in to quieten her down a bit and cut the 'pop's' down, she does sound a tad too sporty for even my liking if im honest!