isv re-route.

[W3RKD 0]

Ok guys we have been doing a lot of research into this as this happening have been evident since the g60 came out. All isv’s bleed boost “FACT” they are not leaking / faulty so by fitting a re-route kit etc is not going to yeild you any gains “in our opinion obviously” as steve says in the other post all you are doing is creating an open boost circuit as the car will be overboosting more of the time as you putting it back in etc.people who recomend these should really understand how these things work.

 

Here’s how the idle stab valve works on boost if I understand it correctly.. :oops:

 

The isv will open when the inlet manifold pressure[AKA BOOST] is above 0.8 bar and vent excess boost either back down the boost return pipe[ not good as this will be hot used boost] or as we prefer through a small k&n breather filter.[This is a separate issue with blanking off one side of the charger etc etc i write about this next. 8) ]

 

Ok so if any pinking is detected, the timing will be retarded by 3 degs for the cylinder affected. The timing can be retarded as much as 12 degs to reduce pinking. The maximum difference between two cylinders is 9 degrees so I have read in the vw tech data.

 

Now if the ecu still is detecting pinking after the timing has been retarded by 12 degs it will now open the isv and vent boost via this method. The ecu will then start to advance the timing in .3deg increments at a time until the ecu is happy again

Once the ecu is happy there is no pinking it will be returned back to std boost and normal fuel map will be continued….

 

We still have lots of work to do on this, but we will sort it ! maybe removing the isv is the answer like the euro boys do ,maybe not until we know for sure we will continue to work on it. we have some diagnostic equipment coming that will”I feel” be the key to the door in explaining this once and for all and them maybe getting some code written to sort this out. Who knows? Just save the money and don’t think a boost re-route is going to stop this happening IT WONT.

[steveo29 0]

is a check valve a good or bad theing then?

[scruffydubbers 0]

Just found an interesting link on the vortex forum explaining about the isv reducing the boost, like darren was talking about.

 

http://forums.vwvortex.com/zerothread?id=1238044

 

So if you had the engine/timing/fueling all set-up correctly do you think it is safe to remove the isv?

 

i guess the idle could just be adjusted manually :?:

 

would this effect the cold starting?

 

i surpose a check valve would reduce the boost leaks, but would also prevent the isv reducing the boost if it needed to

[andycowuk 0]

Ok so if any pinking is detected, the timing will be retarded by 3 degs for the cylinder affected. The timing can be retarded as much as 12 degs to reduce pinking. The maximum difference between two cylinders is 9 degrees so I have read in the vw tech data.

Now if the ecu still is detecting pinking after the timing has been retarded by 12 degs it will now open the isv and vent boost via this method.

 

Is the fuel injection in the Digifant batched or grouped or sequential? Couldnt the ecu give more fuel rather than retard the timing?

[GazzaG60 0]

sam at sns said something like the following when i asked him

 

some ECUs can put more fuel in when knock is detected.

 

cold start is a pain whe its removed. although does it get that cold over here.

 

good mapping will overcome isv issues. this is in place so that eeegits can put crap fuel in and not pop it.

 

basically prevention (ie good mapping) is better than a cure.

 

also some ECUs bleed boost over 0.8bar so your loosing some over that.

[W3RKD 0]

http://fastpurple.co.uk/g-werks

 

there you go have a look some testing we did on a 3rd & 4th gear power run ...

watch the isv bleed...

tested car was> on SNS map / 68mm pulley / unported charger.. thats all.

[W3RKD 0]

http://wsidecar.apple.com/cgi-bin/qtc/n ... &brow=msie

 

download quicktime to hear it with the sound. here...

[andycowuk 0]

Was talking to G60Racing about this today .... just thought i would ressurect it as it is pretty useful!

[Supercharged 2]

Yes funny this has come back almost a year after it was started, especially as I've just taken out my boost return pipe!

[stel g60 0]

yeah im waiting on the guys for this. i cant run max power cos my boost was bleeding down to about 11 psi. the timing was retarded slightly to stop it but i need to advance it up again. im becoming a bit of a power junkie. when i bought the car the isv was blocked off and the car did seem to run fine although it idled on 800, it was pretty standard engine wise then though.

what i dont understand is why did vw make the g60 like this but the g40 engine dumps more fuel instead of bleeding.

[Rossco 0]

Im well confused, what does all this mean, i couldnt follow dazzers first post. Give us a breakdown boys

[Shilakadaddy 0]

yeah I'm still a tad confused too... Does it only come into play when the engine starts pinking, or is it active all the time?

[andycowuk 0]

in bullet poitn form.....

 

[1] car happy.... no pinking, no bleeding from isv
[2] u boot it, engine pinks knock sensor hears it, ecu says " a-ha"
[3] ignition timing retarded a bit
[4] listens for knock...... if its all good, it lets the timing go back to norm if its bad, it retards a bit more
[5] still pinking - bleed boost
[6] all good - back to norm

 

stel g60our MPG is low enough, without the car doubling fuel delivery just cos u have been sitting in traffic for 10 mins!. Remember the digifant is a compromise of a whole load of problems..... economy was probably the thing that swayed it in the direction they went.

[potatonet 0]

I just unplugged mine, it idles about 1200. best way to Defeat boost transfer.

[Henny 0]

potatonet, yeah, but by doing that you're not allowing the engine to prevent pinking at high boost (therefore high revs) which may result in a rather large bill to replace your melted pistons! :|

 

I'd rather loose a little boost when the ECU detects pinking then melt my engine... ;)

[Shilakadaddy 0]

so as long as the engine is set up properly and not pinking, this thing will sit there quite happily without venting boost? :)

[Henny 0]

yup, as long as the ISV is OK too... 8)

[Timo. 0]

potatonet, yeah, but by doing that you're not allowing the engine to prevent pinking at high boost (therefore high revs) which may result in a rather large bill to replace your melted pistons! :|

 

I'd rather loose a little boost when the ECU detects pinking then melt my engine... ;)

 

:shock: :shock: Blimey. Think I might put it back on my Dad's g60 before it comes out of hibernation in April!

 

T.

[potatonet 0]

then I am glad that plugged the thing back a few months ago, It wasunplugged for about a year, probably why I blew the headgasket

[W3RKD 0]

so as long as the engine is set up properly and not pinking, this thing will sit there quite happily without venting boost? :)

 

erm no as stated in my origanal post is the map sensor dectects over boost this is when the isv can open ..

 

yup, as long as the ISV is OK too... 8)

 

ian is this a joke ? :? you have read the above yeah ? THE ISV IS MENT TO BLEED BOOST ITS NOT LEAKING... :lol: 8) :lol:

[Henny 0]

erm, Daz? re-read what I was replying to... :? :roll:

 

Am I wrong when I say that as long as the ISV is in good condition and the engine is not pinking or over-boosting (more than the map can handle due to a smaller pulley) then the ISV will not vent boost? (I'm happy to admit that I'm not 100% sure on this, but then, I don't think anyone really is, so please correct me if I am wrong... 8) )

 

I was VERY careful to not use the word LEAK, a faulty ISV may LEAK boost, but a correctly functioning one should only vent it when the ECU gets a little unhappy with how the engine's running... 8)

[W3RKD 0]

ok .. i have re read what u said again "it was early" and yes an isv will not vent boost until the limit of the map sensor is reached. i guess this is the problem with our charger rebuilds as when flowed 99% of them hit 1.1bar "on a 68mm pulley" hence why we have had to address this issue so much... :D

[Henny 0]

phew! I thought I was loosing the plot there! :lol: Thanks for clearing that up... 8)

[Cougar 0]

Ok, I have my ISV re-routed to the boost tube instead of the return. So what your saying is that this could cause an over boost situation if the ECU determined that venting was necessary? If this is the case I'm considering capping the TB end of the return tube and leaving the ISV and oil breather attached to it. Could this cause too much suction to the breather though?

[Guest]

I think I'm getting it...

 

When you refer to the map sensor.. if charger is ported etc then sns chip used.. does this partly/resolve the problem?

 

Or am I well off!