Dum-Dums VNT 2.1TD OEM+ Bianca Estate. (loads of pics and video now added)

[akuma406]

I have to learn to read these maps turbo, because I understand nothing. . .
Do not try to be useless esplicarme by the language barrier, I will seek information directly into Spanish

[Dum-Dum]

@ 1.5bar your airflow at 4200rpm would be 21.5lb/min.

The main thing that a later generation compressor will do is allow higher pressure ratios.

Yeah, I guessed (worked out) it was 16-21lb of air, i can has mathematics

I have to learn to read these maps turbo, because I understand nothing. . .
Do not try to be useless esplicarme by the language barrier, I will seek information directly into Spanish

Ruan posted something in the XUD section that might help if you can translate it but I don't think I could properly explain it in english far less in spanish. Good luck with finding the information though as I certainly found learning about them interesting.

[silverzx]

Looks good mate. Shame about the vane stop & actuator position.

[Dum-Dum]

Looks good mate. Shame about the vane stop & actuator position.

Yeah but its just like adjusting a bosch pump, you know what the screws do, they only adjust 2 ways and so its just trial and error (sadly taking the turbo off every time)

Its decided that its not going to return all the way to the stop now so I have nothing low down but I can't see there being much wrong, probably just the actuator settling into being used for the first time in at least 3 years or me not of having tightened lock nuts properly.





Anyway I got a puncture last night, well, I say last night buy my tyre mysteriously went flat after the first time I drove the car but I pumped it up and it had been fine since. It was still inflated when I left work last night and ended up rather sideways about 3 miles up the road but its always covered in diesel and slippery so thought nothing of it. Another 5 -10 miles up the road at another roundabout ended up sideways again and knew there was something wrong, pulled over and low and behold a flat tyre NSR that I hadn't been able to hear or feel, tried pumping it up to no avail, couldn't feel a foreign object in the tyre so fired in a can of tyre weld.

[attachment=18604]




Did the 10-15 miles it recommends to let it set at 40mph (straight up the A41) and the car had felt OK but then it really is pretty much non stop straight line at 40mph and pulled into a lay by, It still looked flat so I got the pump back out and had a go. 3 mins later and still 0psi so had a better feel of the tyre and found a hole in the rear sidewall I could get my hand in. Contemplated calling a cab to go home and pinch a wheel off the rallye but it was £20 each way so called the AA

Called the AA at 00:10 and the bloke on the phone was saying they have to send a patrol to assess it and see if they can repair it at the side of the road even though I could get my hand in the hole and if (when) that doesnt work then they call out a 24 hour tyre place to fit a new tyre, the AA pay the callout and I have to pay for the tyre (and you can bet that wont be cheap). If they cant get a tyre fitter with my uncommon size of tyre on a bank holiday at 2 in the morning then and only then will they tow me home. Anyway it turns out my buckets are at least reasonably comfortable for sleeping in when reclined and the patrol arrived at about 02:10.

The patrol aggreed with m verdict that the tyre was f*cked but fortunately common sense prevailed for him and he was happy to drive the 10 miles back to mine and pick up a spare off the rallye (and some flat seated bolts) and drive back and fit it. I think he was also happy to pick up my low entry jack too LOL as the AA ones never go under.

So at about 0250 I left the lay by sporting a nice shiny cyclone.

[attachment=18605]



Got to a tyre shop this morning and this is the old tyre.
Think it might of gone flat rather soon after leaving work. Amazed I couldn't feel it flapping about.

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[attachment=18607]

[silverzx]

Use tyre .. As .. Means of .. Flash light? [FACE WITH STUCK-OUT TONGUE AND WINKING EYE]

[mr_fish]

brilliant job at that tyre, sounded like a long night.

So are you just letting the boost operate the actuator? no MBC involved?

[Dum-Dum]

brilliant job at that tyre, sounded like a long night.

So are you just letting the boost operate the actuator? no MBC involved?

Nope, pure boost straight from the manifold to the actuator. It works very well like that as the actuator starts moving at just a couple of PSi so the preload on it tunes exactly when the vanes start opening.

The only problem I can see is there is a trade off between opening the vanes nice and early (little pre load) to getting a big top end pressure (lots of pre load) but I can't see how a MBC would help that, the only way of changing this characteristic would be electronic control which I don't want.

I suppose I could go for a slightly more progressively sprung actuator or possibly alter the lever length of the VNT control arm itself.

[Piggy]

That maybe why its so laggy mate. Want it to just hold the vanes initially.


And as to Jamapics comment.... Yes I guess its not MORE air...but much denser, better air rather than more air

[jammapic]

And as to Jamapics comment.... Yes I guess its not MORE air...but much denser, better air rather than more air

At the end of the day, boost is boost, the same amount of air mass flow will make the same amount of boost.

A bigger turbo can make the same boost with less heat, and obviously that heat contains more oxygen, which means more bang. So you can actually run less manifold pressure to obtain the same power output. Also, the bigger turbine side allows for less back pressure, and less loss on the motor... i.e more power for less boost.

Have a look at Ruan's post on boost vs flow, that explains it all really well.

JP

---

Maybe I'm just being pedantic.... :-P

[Ruan]

I think the confusion is over volumetric flow vs mass flow - one's about the space it takes up, one's about how much it weighs - cooler, denser air weighs more!

Air MASS is what we're interested in - however we think about turbochargers being volumetric movers.

With regards to vane position - you want the vanes to stay closed for a little while, it's WAY too laggy in your video, this should spool way earlier than that - a manual boost controller will help - I used mine with an MBC - you've just got to monitor EMPs as you can quickly cause damaging EMPs with vane stop adjustment - so you've got to go easy on it.

There's this idea that an MBC keeps the boost away from the actuator then suddenly opens it, which it doesn't! The ball and spring "flutters" up and down as air pressure increases, the preload on that spring dictates when it starts fluttering, the reason they're better than a bleed valve is that a bleed valve only works if there's air flow - if the air isn't moving, eventually the pressure will equalise - just much slower due to the restriction.

[Eeyore]

Did you not check all of your tyre pressures before driving home? That's a standard check mate. Even if you wanted to risk your own life it is extremely selfish to risk the lives of other road users. X


Anyway bad luck. Good that the van driver saw sense. Some people are just thick as shit! I ruined one of my tyres like that. Only drove 100m after a puncture and it had similar holes. Very annoying. Glad you've got it sorted.

[Piggy]

Is weird how you didnt feel that Dumdum. Sure you would have felt a wishbone collapse though...no?!

[akuma406]

Ruan you is like a book ajajajaja
As do the pump timing by ear, listening to the engine or a clock openwork?

[Dum-Dum]

Did you not check all of your tyre pressures before driving home? That's a standard check mate. Even if you wanted to risk your own life it is extremely selfish to risk the lives of other road users. X

Actually as you can see from my post I did check before driving as I knew there may be a problem but it wasn't when I set off.

[Dave]

My 2260V needed a good 28psi to make it properly haul. I ran 22psi for a while, but enevitably more boost did make more power so the maps went out the window to overcome the VE of the head.

[Dum-Dum]

So I've had confirmation that she's no slouch after taking my best mate out today (he's been in every single one of my 306s so probably a very good judge of how fast it is).

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This was after I'd had a play with the turbo and found out why the boost had dropped, the actuator had come loose so its re adjusted and running 22psi peak now and coming on boost a little quicker, could still be better low end though. It'll stay like this till after I come back from Scotland though.

Oh and I gave the boost hose that was popping a good blast of tesco value hair spray and a proper clamp and its been fine since

[Piggy]

Good lad!

Maybe worth getting a EMP gauge setup then you can bring in that boost sooner no problems!

[Dum-Dum]

So my turbo keeps deciding that it doesn't like boost and to slacken off the actuator rod. I think its to do with the heat cycles and vibration but its f*cking annoying having to wait for it to cool to have to retighten it.

[jammapic]

Spot of weld...

[Dum-Dum]

I was hoping I could get some thread lock (or superglue) in there.

[Piggy]

Not got a locking nut on it??

[Dum-Dum]

It has a locking nut, it just doesn't work even when its so tight its twisting the adjuster.

[Piggy]

Mines shaking terribly but not coming loose...whats up with yours!!?

Add another locking nut against the locker

[Dum-Dum]

Yeah I might thread on a nylock the next time shes apart and double lock her but I get the feeling that because of the way the actuator arm is almost always pulling away from the pivot apart from when its on boost (above about 7psi if i guess right) that as soon as there is any heat cycles they move apart a tiny bit and are then free to do as they wish.

[impotentials]

All looking good and clean.

[Dum-Dum]

All looking good and clean.

Cheers mate, shes a f*cking weapon.

[Dum-Dum]

So did I mention I blew the turbo. Infact I've done nearly as many miles with the turbo dead as I did with it working. Sadly I can't post pics or videos as I'm on my phone on holiday.

[Piggy]

No....blown turbo? This is news

I wondered what the black smog was on the news!!!

[Toms306]

That was worth it then!

What happened, just overboost or something else?

[1616six]

Is this another one of your creations?!?