Ready for Wastegate porting...

[TiddlesRX7]

Thinking about it. I know a man that can get one if you need. Soldave on here is based out in Japan and can get his hands on all sorts of stuff new and used. I bought my ARC intercooler off him for a very good price. Maybe worth giving him a PM.

[Prof]

Hi Guys - just back from a short weekend
 
I\'d agree with Clive - it\'s a good idea to get a mechanical boost gauge on the car - only because electronic ones have that extra layer of complexity, and the stock one is useless apart from telling you that you have boost - but you\'ll know that already
 
As for boost controller - a good eletronic one that can keep track of peek readings and cut back to safety when over boost is detected is probably a good idea too.
 
Since the wastgate was ported, I haven\'t had issues with boost creep - nor has mitch - but both our turbo\'s have something else done on the exhaust side.
 
Mitch has a bell mouth that covers the whole back of the turbo - and replaces the normal down pipe and rear plate on the back of the turbo
 
I have a spacer that adds another 1cm to the rear of the turbine housing - like a thick gasket - before the end plate
 
The idea of either of these mods is to allow the wastegate flapper to open a little further - as it only opens a little way.
 
Basically you can still get some creep even with fairly aggressive wastegate porting - depending on exhaust and intake modifications.
 
Both Mitch and I have had problems with the wastegate actuator - the stock one started to let go just around 9-10 psi - I don\'t think this happens on all cars - it will be to do with the spring - keep in mind that the stock actuator was meant to open at 5-6 psi, and the stock boost solenoid delays it\'s opening until 8-9.
 
I use a FORGE actuator - dual port, with a 4 way solenoid - Mitch is using my old HKS actuator - which is a direct replacement for stock - you can run easily 1 bar with this actuator - turbo permitting.
 
A boost controller can\'t compensate for boost lost due to the actuator giving up on the spring, nor can it compensate for boost spiking due to insufficient wastegate bore.
 
The boost loss issue showed up like this:
 
Come on boost slowly and reach maybe 8-9 psi - the boost would hold rock steady and not drop off.
 
Come on boost hard (flooring it in low gear) and the boost would hit 12-13 psi and then bleed right off - you could repeat this over and over - unless you built boost slowly it wouldn\'t hold it.
 
Boost creep - which basically means the wastegate is too small - will be shown as a steady and progessive increase in boost when on the gas, which will be worse in higher gears.
 
Obviously it\'s not controlled boost, but as far as the engine is concerned - as long as the fuelling/timing is good then it should be safe.
 
BTW - according to the service manual - the MAP sensor affects fuelling amount, the 3 emissions solenoids, the stock boost solenoid and the ignition timing.
 
Finally - for taking the turbo off :
 
you\'ve an oil feed and oil drain to detach - oil feed can be undone by the front of the lower inlet manifold, and oild drain by the front cover - just under the oil metering pump.
 
Then there is water feed - 2 x 10mm on the lower inlet manifold - near the split air pipe - that\'s the hard pipe on the turbo - then there is a rubber hose that connects into the back of the water pump - easiest place to detach the water drain.
 
Then there\'s 2x10mm for the heatshield, and one underneath - to get the sheild off you will likely have to remove the lambda sensor - then you can slide the shield off and around.
 
Then 4 large bolts hold the turbo on to the lower inlet manifold - undo them and it should come out.
 
( I have assumed that you\'ve already removed downpipe, all intake piping and the boost lines from the compressor )

[infernal]

OMG thank you so much Dave! I want to be like you someday... :o
:god:god:god:god


Should I buy any spare parts prior to disassembling? Like lines, gaskets and stuff or if we are cautious everything can be reused?

[Prof]

I would replace the gasket for the water feed - as it will probably leak if you try and reuse it.  Also the gasket on the oil drain may give you problems - although there is no pressure on this - they are reasonably cheap in any case.
 
Gasket between turbo and manifold should be reusable if it\'s not damaged.

[infernal]

Thanks!!!1

[TiddlesRX7]

The boost loss issue showed up like this:

Come on boost slowly and reach maybe 8-9 psi - the boost would hold rock steady and not drop off.

Come on boost hard (flooring it in low gear) and the boost would hit 12-13 psi and then bleed right off - you could repeat this over and over - unless you built boost slowly it wouldn\'t hold it.

This is what mine is doing now. Although mine is hitting upto about a bar sometimes (depends on the outside temp) and it doesn\'t drop off mega quick. But it does drop down to 5-6psi. I\'m sure its still spiking slightly too though depending on how im driving it. Which tbh is off boost at the moment, well mostly! When I eventually get some money to spend on the car again I\'ll buy an uprated actuator but in the mean time I might try and make one up using something off another car.

[TiddlesRX7]

Dave. Replacing the actuator with one like yours, does that eliminate the boost hitting 12-13psi then?

[Prof]

Dave. Replacing the actuator with one like yours, does that eliminate the boost hitting 12-13psi then?

Not necesarily
 
With the new actuator - I can set the boost controller and the boost will then hit the set boost and stay there all the time I have my foot on the gas.  If I set the boost controller duty higher - the boost is higher - currently I\'ve set low boost at round 9 psi, and hi Boost at 11 - the highest it\'s hit is 11.7 - although with the Greddy Profec B you can only set duty cycle, start boost, gain and stuff like that.
 
If you see sudden boost spikes (and I mean sudden - within a second or two and dropping off as quick), then this means the gain on your boost controller is set to high - it\'s hitting its boost target to quickly and over running, then falling back to keep it regulated.  A good boost controller should progresively zero in on the desired setting.
 
They can be a lot of messing about - as you need to set them up in a low gear, then test the settings in the next gear up and so on - also try driving hard up a steep hill - that\'s really going to make the engine work, and the settings on the boost controller will show their true effects.
 
On a dyno - a really well controlled boost curve should be dead flat at the desired boost - all the way through the pull.  You\'ll always get drop off at the end - and that\'s to be expected - but you want it at the end rather than half way through your rev range.
 
If you\'re boost is leaking off really slowly with increasing revs, that may just be the turbo - you\'re getting out of it\'s efficeiency band - the effect becomes more marked the more boost you run.
 
Some boost controllers like the AVCR allow you to compensate for gear/rev settings and thus tweak the top end response to compensate - I don\'t have that on mine.

[TiddlesRX7]

Ah got ya. So do you by chance know what rating the HKS actuator is or what yours is set at? 0.8, 0.9, 1 bar? Just there are a few cheap ones knocking about off cossies etc that im sure I could mod to fit the FC. I take it you fit one for say 1 bar then set the boost controller to cut in before the actuator would normally open. thus holding whatever boost you\'ve set it for.

[Prof]

Ah got ya. So do you by chance know what rating the HKS actuator is or what yours is set at? 0.8, 0.9, 1 bar? Just there are a few cheap ones knocking about off cossies etc that im sure I could mod to fit the FC. I take it you fit one for say 1 bar then set the boost controller to cut in before the actuator would normally open. thus holding whatever boost you\'ve set it for.

The HKS one is adjustable - it\'s about 7psi on the lowest setting, and can be adjusted by tightening the actuator arm to about 1 Bar.
 
Ideally you want one around 7-8 psi (1/2 BAR) to start with, so that you\'re boost controller can raise that level but give you a good range.

[infernal]

Hi all again after a while...

If I install a dual port actuator with an electronic boost controller that supports it, can I use a lighter spring in it? Let\'s say 3psi? Will the secondary port of the wastegate compensate and keep it shut against the exhaust gases force?
I just want to have a huge range though the boost controller, let\'s say from 3psi to 14psi. :driving

[Prof]

Hi all again after a while...
 
If I install a dual port actuator with an electronic boost controller that supports it, can I use a lighter spring in it? Let\'s say 3psi? Will the secondary port of the wastegate compensate and keep it shut against the exhaust gases force?
I just want to have a huge range though the boost controller, let\'s say from 3psi to 14psi. :driving
 

I wouldn\'t be tempted with such a low spring - The ability of the spring to hold against it will be related to the spring pressure.
 
Although - as you have a 4 port solenoid - you are basically using the boost pressure to hold the gate shut until you reach your \'start\' boost (greddy profec B speak), at which point the controller will pulse the boost pressure to either side of the gate proportionally.
 
You might be ok with a 5-6 psi spring - and that will still give a good range

[infernal]

Thanks a lot Dave master Prof!