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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298   
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Thinking more about the actuator than the turbo itself. Is it operated by an increasing voltage. So if perchance you had a relatively high resistance connection / dirty plug connection things might not work too well? Possibly an intermittent fault and perhaps even one that no one could detect for 3 years?
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27th Oct 2013 12:06pm |
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| farmer giles Member Since: 09 Feb 2011 Location: worcestershire Posts: 1299 
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the turbo only works over 2000ish rpm so your turbo never works
the foot pedal on the far right has to be pushed so far down that the engine makes such a loud noise you can't hear any rattles, but you might just hear the whistle of a turbo.
admittedly this wasn't the helpful forum answer that you were looking for but you are always welcome to come and drive my 110 for comparison  |
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28th Oct 2013 4:40pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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if it wasn't for answers like this the forum would be v boring. I know this is going to sound like the 'same old' but as mentioned somewhere else - I think. car was in for some work recently and with regards to the engine they couldn't find anything wrong.....they did however give the electrical connections a spray / clean along with cleaning the maf and map sensors. I drove home with a great big grin ....... engine running really smooth. to point that I was merrily overtaking people  and could hear 'THE WHISTLE'.... bl**dy great !
but didn't last long....100 miles or so later back to the mostly (not always) clatter ...... I've since tried cleaning sensors and connections but no difference. ... ?? after giving them a clean I went for a drive and no difference. when I got back however I gave the engine a few blips in neutral stationary upto c2000 rpm and it sounded very smooth however on the one occasion the rev counter needle stuttered around 1750rpm......now this is a speed that I've always had issues with and had put it down to the prop (which has re cently been replaced)....could it be a slightly sticky egr? for a long long time I've suspected a dodgy egr and map / maf sensors but I'm relunctant to shell out for these A if they're under warranty and B if they're ok?? when you round for that test drive Mr F G. ? lost my way here and forgot to mention about the 'how does the turbo work'.....was wondering if cleaning the connections on the turbo actuator (ie reducing the resistance of the connection) would like make much difference? |
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31st Oct 2013 8:38pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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does anyone know at what rpm the turbo starts to have an effect....is it pretty much >1000rpm?
obviously it must be at full tilt by c2200 rpm hence max torque? Its just occured to me ..... the turbo vanes are variable....are they infinately variable or simply 2 position and would they by any chance change angle at circa 1750 rpm? |
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4th Nov 2013 11:46am |
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| farmer giles Member Since: 09 Feb 2011 Location: worcestershire Posts: 1299
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come down to junction9 of the m5 and i will take you for a spin.
i know that the turbo on the td5 only kicked in at approx 1900 rpm, i would assume that it is similar for the puma. come an have a comparisson drive to put your mind at rest |
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5th Nov 2013 3:20pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731  
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Just revved a bit on the driveway and the Scangauge only starts to show boost around 1900rpm - very little at first but increases quite fast at 2500, 3000 etc. It's much more significant when on the motorway - with my "Houdini" turbo it's something I watch quite carefully.
Hope that helps 
Cheers Matt Tell someone you love them today because life is short. But shout it at them in German because life is also terrifying and confusing... |
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5th Nov 2013 7:11pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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thank you for the replies.
interesting I'd have thought the turbo would have been spining long before max torq? I believe the turbo is variable vane, does the actuator operate this or does it operate the waste gate (I presume there's a waste gate (of sorts)?) and are the variable vanes 2 position or are 'infinately' variable between min and max? interesting stuff huh? |
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5th Nov 2013 8:17pm |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436  
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I'm sure there are better experts out here to answer this but here what i seem to remember
turbo works always, driven by the exhaust gasses, more exhaust pressure more boost The variable vane turbo adapts the position of the vane to reduce boost when revs go up, this to avoid over-pressure, hence no dump valve necessary and a "constant" boost pressure The geometry is such that at low exhaust pressure the optimal boost is reached earlier and then reduced as pressure rises. With a fix vane you have to design the vanes so that they reach maximum allowed boost at maximum revs, which makes them quite ineffective at low RPM, turbo lag and all that Free revving does not show anything, you need to create a pressure differences both on inlet and output side and this shows "under load". i am expecting the ECU is also playing with other parameters to have optimal vane setting related to egr, revs, accelerator position/movement etc but watching my scangauge i saw that boost rises almost instantly till around 1.3-1.4 bar above ambient pressure and then stays there. (note: under load) Eg If your modulator plug is defect your pressure will rise above 1.5 bar under full acceleration or heavy load and the limp mode is triggered. this always happened to me above 1900rpm, but load was certainly a big deciding factor. but yes i have a "magic" point around 1900 rpm where i suspect the turbo vanes retracting. I noticed 2 things at this same point, EGR going open under load where it was shut below and consumption on long trips easily 2l/100km up when going over this 1900RPM.(aerodynamics will also play a role) correct me if i'm wrong, as said no expert on the subject at all
of no importance anymore to me all possible issues solved since BAS remap  even my clutch rattles less since continuously getting kicked by the engine |
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5th Nov 2013 8:58pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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thanks tatra805
will go through that again and think some more about what you've written. do you think 1900rpm could show as 1750 rpm on the rev counter (how accurate are they?). if there was a poor / faulty / intermitten fault on the turbo actuator what kind of effect would you expect at low revs under load and at 1900 rpm under light / medium load? norm....are we talking about the same thing? i think most of that went straight over my head. are you by anychance talking about the set up seen in the twin turbo 3ltr straight 6 bmw's ?? (I'll have another read through I'm sure its very correct but its also seems very 'foriegn' to me?? |
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5th Nov 2013 9:14pm |
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| Norm4n Member Since: 31 Aug 2012 Location: Surrey Posts: 329 
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Your right I'm talking
  thought you meant twin scroll, but you didn't!
Think this is what you were after http://www.turbotechnics.com/news/vnt_clean.htm |
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5th Nov 2013 9:21pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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interesting - thanks for the link
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5th Nov 2013 9:35pm |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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catherham i read about sticking vanes and all that but i expect
- feedback signal from the module to trigger a fault code when vanes stick - no effects from a blink-of-the-eye malfunction as this thing is spinning at 20K in case the actuator doesnt work but signals are ok (eg actuator arm fell off) you have 2 possibilities - vanes are wide open and you get overboost (mil light and limp mode) - vanes are closed and it drives as a pig (no power) at low revs and triggers a low boost code at revs Your 1750 rpm are a known flat spot with this engine, i even got a bit of kangaroo-ing on a certain false-flat road when keeping speed steady at 50km/h in 5th This all gone with the remap btw I really recommend you to take the offer to compare your car with another one, you will sleep better afterwards or at least know how bad yours is. And if you want to be sure, call BAS and let him have a go. I promise you that the only thing you will regret is not having it done earlier. |
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5th Nov 2013 9:35pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6298
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I'd heard that there was a flat spot but didn't know it was at 1750 rpm..... do you also get a vibration at this speed....can feel it through the floor / accel pedal.... not major .... a bit like you can get on different road surfaces?
o I'm very keen to get a remap but I want to be 100% that everything is as it should be first? I'm going to try and sort a test drive however at present if everything is as it should be I can't for the life of me understand how sometimes the engine smoothly buzzs along beautifully in top and sometimes clatters along with an apparent lack of power under the same circumstances ??? - just thought. I believe the disco 3 upon ignition stage II the turbo actuator moves....a bit like the egr clean cycle. any idea if the defender does the same? |
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5th Nov 2013 9:44pm |
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| tatra805 Member Since: 16 Aug 2011 Location: Dolany Posts: 436
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seeing you keep struggling and fighting with this i guess you're not married then...
joking aside, it's just like that and how do we know conditions are the same? atmospheric pressure, temperatures of air and water, fuel temperature, each sensor (eg accelerator) in exact the same position? heck even wind from the front or back makes a difference but again, remap the thing and you're in a different world. I still suspect LR to have made the whole mapping a pig on purpose, it can't be that bad just by accident once you know how good it should be. |
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5th Nov 2013 9:59pm |
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