Ali's drift 360 project

Post by **Stavros** » 26 Mar 2007 12:36 pm

chattering is just the noise of the compressor blades chopping against the air escaping out the boost pipes, which it will do so until the pressure in the pipes returns to atmopheric pressure or you open the throttle again.

its doesnt make the compressor stop or move backwards, thats utter bollocks and almost if not totally impossible, but it will slow the compressor, but how much more than running a dumpvalve is debatable, it wont be much as soon as you shut the throttle the exhaust gas drops hugely to the turbo will slow loads anyhow.

its not as bad as people think, as with everything its all internet rumour from people with no experience of it.

i ran 30psi for years with no DV on my Cossie (with very violent anti-lag too) and no damage, and know countless others with similar experience.

the reason they on most production cars is NOISE SUPRESSION, same as why most cars have long induction piping and restrictive airboxes, hell even in many workshop manuals they named "noise supression devices".
that ones doing a good job of supressing the noise on alis car so far!

if any normal car had loadsa induction noise n chatter youd get people taking them back to the dealers thinking somethings wrong.
ive seen a LOT of modded imports taken to garages with suspected faults cause the owners hearing chattering and fluttering and dont know what it is so think its a problem.

Post by **Ali** » 26 Mar 2007 01:57 pm

Haha BANG ON Stav! Me and Steve had a play about with it this morning, was told it needed a one way valve in it for it to work, tried it the one way, sounded identical (strangely enough the boost came in slower and later

) so turned it round the other way, jesus it chatters! lol, unfortunately it also made a fair bit of smoke and now smokes at idle too lol, I guess the recirc valve is just loud because its a really short metal pipe and cone filter so no airbox to mute it! Definately new turbo time though, again!

Post by **Stavros** » 26 Mar 2007 02:14 pm

Exactly that reason mate, you can hear it like a atmo DV as there no airbox to muffle it.

you should ideally blank it off, but IIRC you cant just put a flat plate over it as that would leave the dump open all the time.

collins or somebody used to make the correct blanking plates for this type of compressor, as late-spec small turbo escort cossies, rover turbos, and some porsche turbos all have this type of compressor housing DV.

about the turbo smoking- what oil feed have you got? too small or partly blocked will cause similar smokey probs, as the lacking of oil fucks the bearings and the oil that does get thru then smokes.
too big also gives smoke as it just gets past the seals.
just having TWO fucked turbos is a mega co-incidence, turbos just dont die that easy without a problem with the oil supply.

Post by **SteveP** » 26 Mar 2007 02:16 pm

Definitely, what Stav posted is exactly what we found this morning. But my, it does go very nicely - just a continuous stream of power from silly low RPM. What powerband 'hole' in the bottom of third gear?! Got a slightly better video coming soon. Smoke is still a concern though

Anyone know how to get Griz to sell a turbo!? Asked him yesterday and he said "I dont know how much"

http://www.youtube.com/watch?v=-rKtV6k3OyI

Post by **Ali** » 26 Mar 2007 02:18 pm

Well the first one was knackered anyway, this 2nd one is off a 940 that had 120k on the clock, doubt its ever been replaced. I'm pretty certain the oil feed isn't too small, I guess it could possibly be too big but I duno, i'll go grab some pics in a bit n see what you think. Some of the time its hardly smoking at all and other times theres shit loads, also it seems to hardly smoke on boost, then change gear and a big cloud a couple of secs later

Post by **Stavros** » 26 Mar 2007 02:42 pm

also worth noting, like normal dumpvalves, its not wise to leave the vac connecter to the bypass thingy on the compressor unplugged, as dumpvalves use the pressurised air thru the vac pipe to equalise pressure both sides of the diagphram to stop it opening under boost.

with nothing going into the vac pipe end the boost will push it open, as the spring rate alone wont keep it shut.

at best this will overspeed the turbo to keep the boost up, giving you less turbo efficiency which means lack of power and possibly a worn out turbo as your overspeeding it.

at worst you wont get full boost as well as the above problems.

infact, if the bypass is faulty (maybe diagphram split etc) then the turbo could be overspeeding (as its fighting the boost leak so spinning faster than it normally would for the boost) and killing your turbo, hence the smoke, BUT again, thatd be v.unlucky on both turbos.

for these reasons tho, id deffo be wanting to invest in an appropraite blanking plate to remove that setup totally.

im not sure who well them now, let me find out...

Post by **Ali** » 26 Mar 2007 03:29 pm

Can't i just carry on using this one way valve the wrong way Stav, seems to work fine to block it off? Luckily its not too much of a bastard job to change the turbo on it anyway, I need to remove the exhaust system anyway to weld on some proper mounts instead of the electrical wire currently holding it up

Post by **Stavros** » 26 Mar 2007 03:32 pm

well thats the thing, if there no air getting to the vac side of the DV the boost will push it open a little or totally.

if the one way valve means no air is getting to it, then you may as well blank it off, as thats the same thing.

but if its the other way round then TBH that sounds ok, as the first boost will pressurise that side, and then the pressure will stay, meaning it wont open, ideal.

either way, i can get blanking plugs for 16quid it seems

Post by **A M R** » 27 Mar 2007 06:04 pm

the problem could be something really simple as to why its smoking:

could it be smoking because its running rich? get an afr meter to find out for sure.

has the turbo accelerated the wear of your rings/made what was already there show up more?

its probably not, but worth a look anyway.

Post by **SteveP** » 27 Mar 2007 06:21 pm

A M R wrote: could it be smoking because its running rich? get an afr meter to find out for sure.

has the turbo accelerated the wear of your rings/made what was already there show up more?

Errm... no, and er... no. AFR is monitored via megasquirt and a laptop. It's turbo oil issues for sure...

Post by **A M R** » 27 Mar 2007 06:26 pm

ah right didnt know that. you love putting me down dont you?

lol

Post by **SteveP** » 27 Mar 2007 06:28 pm

Sorry, but all the potentials for the oil burning have already been mentioned above, engine wear doesn't appear overnight

Post by **jtbo** » 27 Mar 2007 09:11 pm

SteveP wrote:Sorry, but all the potentials for the oil burning have already been mentioned above, engine wear doesn't appear overnight

Only if it is piston ring and symptoms seem not to match that one

AMR, don't get put down, it is just that you are young and you have not yet learned all stuff, in other hand you can pick up things old farts can't even think about, takes time, but when you memorize all stuff you learn it is in no time that you find out that you start to be more and more right

Post by **redline** » 27 Mar 2007 10:30 pm

jtbo wrote: [AMR, don't get put down, it is just that you are young and you have not yet learned all stuff, in other hand you can pick up things old farts can't even think about, )

did you have any particular old farts in mind Jani lol

you are never too old ( or too young ) to learn my 9 year old daughter is learning the basics now and picks things up very quickly

Post by **germ** » 27 Mar 2007 10:42 pm

learning the basics of what?