Decoking...

Post by **aidanjaye** » Wed Jun 10, 2009 10:11 pm

Might not have designed it but they use it (and charge for it) on their cars...

Post by **ArthurPE** » Wed Jun 10, 2009 10:17 pm

silverRS4 wrote: A few textbook +/-, smilies and periods...do not .... close the book .. on this...sorry . A flowbench test with clean valves versus severely crudded valves is the only way to even begin to shed light on this issue.

not true...basic calculations build bridges...jet airplanes were designed with slide rules...it's not as complicated as one might think...

silverRS4 wrote: Much design work goes into the stem shape design and valve seat angles to decrease the pressure drop. Crud that is 4-5mm thick at the base of the stem, decreasing to 1mm thick near the perimeter of a valve that opens 12mm changes the flow pattern dramatically. As noted above, the effect can not simply be white-washed with first-order calculations. Saying that a high level of buildup does not effect flow into the cylinder is like saying ice buildup on a wing doesn't effect the lift of an aircraft.

in the scenario you describe, 5 mm at the stem amd 1 at the lip, would have even less effect than an assumed 3 mm evenly distributed...but neither would have measurable impact

silverRS4 wrote:You stated yourself that the your buildup was minimal (similar to Pippys current level) and that your trap was 108 (or whatever). That is meaningless really. Likewise, if you mean the zero decrease is power was "shown" by calculations derived from the simplistic ones related to the flow past the valves, then you are just washing with the same brush.

washing with the same brush as any schooled engineer: you have experimental results, albiet limited sample, and a basic mathematical model..whether you subscribe is up to you, but physics does not need your concurence to be valid...

silverRS4 wrote:The effect of gravity can be "shown" clearly with a first order calculation. Sub-sonic velocities of fluid around a crudded up valve and its effect on the efficiency of an engine can be approximated while making many, and possibly some erroneous, assumptions, but not "shown".

is h = 1/2 g t^2 + vo t + ho a first order differential equation? no

air flow is even more simplistic...every scenario is subject to a basic rule...an equation covering 20% of the variables will yeild better than 80% accuracy...everything is an approximation...

now you have disputed my reasoning, but yet have not shown one error in my problem definition and mathematical treatise...show me the err of my ways...with math, not with opinion...seriously....

that is the beauty of Newton/Bernoulli/et al's work, the simplicity...
Newtonian mechanics are not as accurate as Einsteinian, but for the realm we deal in they work fine...in fact E = mc^2 is so very simple and elegant, and THAT is it's beauty...

Post by **caldy** » Sun Jun 14, 2009 8:10 pm

Looks as if our pals over the pond are getting agitated!

http://www.audizine.com/forum/showthread.php?t=270388

Post by **kiN** » Sat Jun 20, 2009 8:47 am

Anybody heard the FISC treatment?

http://www.megaflush.4-tech.co.uk/fisc.html

The guys at ArielAtom club have tried the treatment, and noticed noticeable improvement.....

Post by **Andyuk911** » Sun Jun 21, 2009 12:00 am

kiN wrote:Anybody heard the FISC treatment?

http://www.megaflush.4-tech.co.uk/fisc.html

The guys at ArielAtom club have tried the treatment, and noticed noticeable improvement.....

That is not for the 'dry side' .. so it won't help the RS4

Post by **ghoonk** » Sun Jun 21, 2009 6:07 am

Just dumped 2 bottles of Forte Top End Treatment to see if it helps. Right now, i'd try anything that might even help slow down the spread of this 'cancer' in the engine

Post by **duud40** » Wed Jul 08, 2009 9:02 pm

Just had a diy go at taking off the manifold and cleaning the intake valves.
It was a pain in the ass to take the manifold off without removing the oil separator. Took 2 pairs of gynaecologists hands. There is really no space to drop anything arround the engine bay.
Cleaning tools were carburettor cleaner , toothbrushes and a screw driver to scrape off muck. It`s really really dirty in there. Also found something that really disolves crud , it`s the gum cutter spray from 2+2 (linly http://store.brownspoint.com/detail.asp ... id=BRKB101) . Didn`t get to finish it today though so just packed everything and having another go tomorrow. No pictures though. I`ll also get some wd40 spray to clean everything up because the engine bay looks like a real mess.

Post by **duud40** » Wed Jul 08, 2009 9:17 pm

Oh forgot to mention. The crud on the intake side of the engine is far from being abnormal . Sure it`s quite a lot of crud and it might even eat 30(ish) hp from your engine but it`s by no means something to be alarmed about. Nearly 70 000 km on the car

Post by **scaghead** » Wed Jul 08, 2009 9:56 pm

cheers for the info duud, good luck putting it back together

Post by **duud40** » Fri Jul 10, 2009 8:58 am

Finished the install last night. Turns out just filling the cylinder head intake tract with solvent and then blowing it away with a compressor was too messy so i just used little pieces of rags (fabric) to suck up the solvent and muck out of cylinder head. One of the flap sensors on the new manifold was busted so I had to change it to one from the old manifold. I was lucky on this one since it was the forward sensor not the one in the back of the manifold so I had access and a blown sensor will put your car in check engine light mode and wont let you rev past 7000 . The new manifold was ported and polished by yours truly. I dunno if there was a performance gain from what I did because if there is I couldn`t feel it and had nothing to compare it to (another car? ). Car definately feels a little less dodgy when changing gears at low rpms ( that could be me loosing torque) and revs drop faster after a change.

Post by **duud40** » Mon Jul 13, 2009 1:25 am

Got some miles on the odo since the de-coking .It feels great, I think throttle response is improved but I don`t know if it`s in my head or it`s forreal (it`s not that obvious). Another thing, either my launching technique has improved (unlikely) or the power output has increased . I say this because since I`ve fitted 275/35/19 it`s always been harder to launch , out of 5 launches i would screw up 3 and the car would bog and then pick up , but now 4 out of 5 launches are good and the car feels more natural.

Post by **davefaedeen** » Mon Jul 13, 2009 1:30 am

maybe just getting used to the car!!!! lol!! Turn off the traction control, and get rid of the bogging down!!!

!

Post by **duud40** » Mon Jul 13, 2009 1:40 am

I always turn off traction controll (fully , by that I mean the light stays lit rather than pulsing).

Post by **davefaedeen** » Mon Jul 13, 2009 1:49 am

duud40 wrote:I always turn off traction controll (fully , by that I mean the light stays lit rather than pulsing).

Snap!!!

My car is going in to get the manifold valves cleaned, will let you know if i feel any difference in performance!!!! hope so!!!

Post by **duud40** » Mon Jul 13, 2009 1:55 am

I also removed the tin plates in the manifold (supposedly they are there for fsi function but damned car is at > 4k rpms while on the highway so I can`t see when fsi can kick in ).

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