2008cc 8.75:1 CR 3A G60 build.

is the hose there yet?

Nope, I phoned before, it will be tomorrow or Monday, if lazy **** posties can be bothered.

Last night I really needed to get past someone who was either drunk, blind or very old. So I knocked the car into 2nd at about 40mph waited till I could see it was clear and then floored it. I don't know what boost i made but the acceleration really took me by surprise and then it was scrabbling for traction on a dry road. It's the most it's ever tried to break traction in 2nd and it wasn't just one bad patch of road. Anyway I ended up hitting the rev limiter before changing to 3rd as I was particularly stunned.

I hope it doesn't make a liar out of me next time I get it RR, etc. Earlier on that same evening I was a bit annoyed and floored it to beat the lights, then suddenly realised I was doing three figures in a 50 zone, oops! I think I've resolved all the peak power issues with this boost leak thing! Can't wait to fit the new hoses and see what it's like with new silicone rather than duck tape!

It will be nice to validate JNL and waynes work too.
Although I don't think Wayne(Chipwizard) work was ever in question.
Still think it would be nice if he printed torque curves though.

dirtytorque wrote:It will be nice to validate JNL and waynes work too.

And my life for the last 2-3 years!

ctwg60 wrote:

dirtytorque wrote:It will be nice to validate JNL and waynes work too.

And my life for the last 2-3 years!

yeah but no one cares about that.

We have new silicone and pulley. Just need new stronger clips! Can't wait to feel the difference. These should expand less too!

when are you getting the clips?
ffs hurry up.

I fitted the hoses this morning with the current big jubilee clips and it makes the same boost as with the repaired hose! Looks like I did a good job repairing the old hose. Making 1730mbar at the red line gets to 1650mbar by 4000rpm. It then wobbles a bit dropping to 1620mbar and then slowly builds to 1700mbar by 5500rpm and then gets to 1730mbar just before the rev limiter at 6200rpm.

So I'm making the same boost again as I did with the standard head (1740mbar). Assuming the new head is reducing boost pressure by allowing more air into the engine then I would probably of been making over 1800hg with the standard head and no boost leak. Who knows now as there are too many variables, still it's rather interesting the way boost rockets up to 1650 by 4k and then struggles to produce much more by 6k, I don't know what to make of it really. It's either really good or really bad. Gonna static pressure test at 1 bar with a gauge this weekend and see what's what.

Any suggestions anyone?

On the old engine it did a similar pattern of boosting. It would rocket up to like 1870mbar by 4k or something and then creep to 1960mbar by the red line.

Rob can you make some sort of pwm circuit to close the ISV? If you can then I can leave it in the boost circuit whilst pressure testing and see if it is closing. I don't think 1730-1790 boost with this engine is unreasonable 11psi would seem about right would you think??

It just has to make more power than it did previously on the same boost. If it can't then it's crap!

yeah should be able to..
i'll do it tonight.

no just closed while I pressure test. unplug loom from ISV and plug in self or car battery powered circuit that will close the ISV. I've got the loom bits and pieces and a soldering iron I just have no idea about square wave pwm whatever stuff!

I like you Rob!

I made one b4 when i was playing around with the ISV.
I'll just use a 555 astable circuit.
Something like this.
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I follow the theory, the application is a bit more difficult!

dprg wrote:This is done because the output pin has a "totem pole" configuration. It can source and sink current, while the discharge pin only sinks current.

OK!

The easiest way to see whether you are losing boost under full throttle is to do it on a dyno (I know not always practical) and basically just squeeze the hose from the isv to the boost return pipe shut with pliers. I did on mine and it gained me about 1psi. You may even be able to do that on the road using a good clamp, although idling might then be difficult...

The 'quickly rising and levelling off' is normal of the gladers, presumably one of the reasons why they are good for low down grunt.

Not much good finding out you have a boost leak on the RR as then you have to fix it before continuing mapping. You are in a unique position with SRR. What was your final boost pressure and charger spec?

Actually the 'squeezing of the hose' was done when I was at Stealth one day. I now boost to around 12-13psi at full throttle (it was about 11 before) and I have re-routed the isv into the inlet pipe. Doing that seemed to get rid of the problem I had with a dipping torque curve in the mid range. The charger is 'Stage 4' and I run a Golf G60 intercooler and associated piepwork.

Presumably with yours the boost pressure will still be limited by how quickly it can get past the inlet valves, more than the fact that you have a 2l capacity.

Have you got images of this?

ctwg60 wrote:I saw 1790 today in a third gear pull from low revs then it tailed off to 1640 still think it's leaking as it drops too quickly from 1790.

Just reading through old posts and came across this. Hmmm I need to test the system properly for leaks as I don't know how I made 1790 earlier than the red line. This is doing my head in! Cheap boost gauge on order!

ctwg60 wrote: Cheap boost gauge on order!

Gauges are your friend.

OK, like a freak, I just fitted 3 other ISVs to my engine and did some full throttle pulls in 3rd. All of them gave different boost levels and you could actually feel when each ISV closed or closed as much as they could, some were really slow to close and others didn't reach 1700hg. I think I'll be fitting a check valve on the boost pipe from the ISV to the boost return pipe. Oh I didn't find one that closed as much or as quickly as my original.

ctwg60 wrote:Have you got images of this?

Of what.....

The reroute.

do you have a spare isv connector?