john banks

When I got my MY00 PPP and DP fitted I had boost overshoot problems with fluctuations - I wanted to run 17.5PSI/1.2bar (given that much above here the TD04 just makes a load of heat and the PPP ECU starts oscillating the boost when I went over 18.3PSI on accurate gauge), but never seemed to be able to get it right by fiddling with the wastegate actuator restrictor orifice.

After hunting around motor factors, and eventually thinking of looking up Pneumatics in the yellow pages and perusing www.festo.com online catalogue and checking for local stockists, I eventually got hold of a flow control valve with correct hose fittings, some good hose and clamps and set to work about doing away with my bruised restrictor pipe and its many times soldered/drilled orifice.

So I hooked up some hose (kindly provided by Kevin @ Falkland) and heavy duty screw clamps (did this after a hose came off and only just avoided the fuel cut at 21PSI!) from the turbo nipple to the T-piece, removing the bent subaru pipe and its orifice. Also upgraded the hose and clamps to the wastegate diaphragm. Really the crucial area for good clamping is on the turbo nipple (this is the one that flew off - much looser when hot!) and the entrance side of the valve as these are the areas which will see the really high boost.

With the valve in place and about 5.5 turns open (out of 10) it gives me a stable peak/held boost of 17.5 PSI in 4th or 5th gear with 17PSI in 2nd and 3rd. It didn't shift even when it reached freezing, but obviously then I had to back off the boost and head home.

One sixth of a turn is very easy to dial in imagining a clock and adjusts the boost by half a PSI repeatably. In comparison, drilling out the old restrictor by 0.1mm (the smallest increment of easily available drills) the boost changed by upto 3PSI!

The car feels incredibly quick and I can get a good level of boost without seemingly randomly going too high and getting the solenoid pulling things back whenever it gets exciting. When I get the Dawes MBC I intend to put it before this valve and disconnect the factory boost controller - see Dawes post for rationale.

This setup would also seem to be a good alternative to a bleed valve in addition to the orifice. Removing the orifice and doing the whole lot with a flow control valve of the right calibre means you are right in the middle of its adjustment range, and you are not fiddling around with it just cracked open.

When setting it up you need to make sure no hose kinks, and replacing the crappy Subaru hosing with thicker walled stuff with inside diameter of 3.5mm (instead of about 4mm) allows you to suspend the valve block away from the turbo, intercooler and oil and coolant pipes which get very hot. Even after a thrash the valve is barely hand hot so can be adjusted. Most of these valves come with a lock nut to hold your setting.

Total cost inc VAT and fittings £14.

Highly recommended for anyone that wants to - up their boost a little, control overboost, or sort their boost out after PPP or downpipe.

Thanks for listening. Hope this is useful.

WUZ

iTrader: (14)

John,
Can you mail me with the equipment required for this or can I get you to order the stuff and I'll send a cheque a.s.a.p.?

WUZ

iTrader: (14)

John,
Can you mail me with the equipment required for this or can I get you to order the stuff and I'll send a cheque a.s.a.p.?

Russell

john banks

Pipemore Scotland Limited
3 Crompton Road
Southfield Inducstrial estate
Glenrothes
Fife
KY6 2SF

Phone 01592 630633
Fax 01592 630623

I had 1/8"BSP(M) x 1/8" Hosetail 2 x £1.57 +VAT
Metalwork 1/8"BSP Flow regulator 1 x £7.37 +VAT

Hose Clips from Halfords - 10/13mm 2 packs of 2 about £1.30 each pack.

3.5mm inside diameter vacuum pipe from Falkland Performance centre.

The hosetails will fit the 3.5mm pipe or the original Subaru vacuum pipe. To save you cutting your original pipes I would recommend gettting some vacuum hose. I have struggled to find it from motor factors/Halfords etc. Falkland are the only place I have been able to find it up here and I have looked hard.

As I say the crucial joint is the turbo nipple - that is the one that blew off on mine when not clamped - my advise - don't even try it unclamped and when clamped and cold it should be almost impossible to pull off the nipple without damaging the hose, but the screw access is difficult for the hoseclip with the HT leads and throttle cable in the way of even smallish screwdrivers.

john banks

Pipemore do next day delivery in Scotland. Few Festo valves that would also be suitable:

http://catalog.festo.com/enu/asp/Def...%27ME%27&L=001

john banks

http://catalog.festo.com/enu/asp/Def...D=151216&L=001

This one would have been my choice - in the end all they had in stock was a valve which controls flow in the forward direction only.

The one I got was branded "Metalwork" as above and quotes max temp 70C and max pressure 10bar (145PSI). At 5.5 turns where I set it it has a quoted flow of 125l/min so if you look for a valve with this well within its range it should be OK. I have only tried one valve so I can't guarantee which ones will work - if in doubt order a few sizes/types - they are very cheap.

john banks

http://www.festo.com/gb/resaleweb/re...%20&%20Transm. these guys look like your local stockist?

mutant_matt

Care to put some pictures up John? This sounds v.interesting

Matt

john banks

No digi camera, but I'll put together a diagram later with picture "inserts" - sounds like Blue Peter....

babber

John,

Funny that, I've just fitted a bleed valve but in series like a restrictor, but I haven't had chance to play with it yet. I left that standard pipe with the restrictor on place and added onto that, to be on the safe side.

But I will tonight after reading this, my boost fluctuates in Fourth and fifth, but seems fine in other gears.

I can take a picture if anyone likes ?

Cheers Phill C

john banks

Picture would be nice if you can.

Replacing the restrictor with a non-bleed valve was my choice because the bent bit of hose was quite skanky and battered and also I thought I would be easier adjusting a valve in the middle of its range rather than at the cracked end. Also didn't fancy a bleed valve and the POSSIBLITY of sucking in unfiltered air off boost.

Have you seen the Lee's Scoobmania site - he fiddled with bleeds in three different positions and found hose C the best - the one off the side port of the T-piece going to the wastegate control solenoid in the wing. Otherwise in position A before the T-piece it was very difficult to adjust - and only just cracked open.

SPEN555

Babber,

I would be very interested in some pictures.

Damian.

HarryBoy

Hi John,

Interesting read.

Just theorising, I thought the restrictor was there to control the boost spike (damping) not the overall boost level. I thought it worked in tandem with the duty solenoid, the solenoid under the control of the ECU dictating the peak boost and boost ramp. Changing the restrictor size alone can influence boost in the context that you are moving away from the ideal size that's matched to the program control of the duty solenoid....

I have removed the Dawes Device on my car due to the report on i-Club until I can get it verifyied, but in the mean time I intend to experiment with restrictor size to give a damped boost response and a bleed valve to raise the overall boost level.


Harry

john banks

I thought the same about the damping control, but that is not how it is in practice on my car. Because of overboost I had to increase calibre of my restrictor initially with PPP and then again with a DP. For some reason my car doesn't seem to peak the boost then settle - it just goes up to a boost level depending on restrictor size and holds there. With this valve I can adjust anywhere from 12 to ridiculous PSI. If it hits 18.3PSI (why not 19.3PSI=1000mmHg? - this is off a calibrate gauge) the boost comes down and sometimes oscillates so I try to keep it 17-17.5PSI depending on gear with a margin for cold/fog. Feels very quick and smooth there with no fluctuations and very quick spool up.

The program control for the duty solenoid was obviously not right once I had exhaust mods, so all I am doing is putting the boost nearer to what it should be.

I don't know if the PPP ECU behaves differently to the OEM ECU. Obviously if you have too little restriction then the boost will never reach target, so peak/held will be the same and lower.

As far as I see it I can't see any reason why bleeding air is much different to changing a single restrictor. The net effect is the same - you are adjusting the pressure on the wastegate diaphragm. It's just that doing it at different sites with different valves produces different sensitivities and adjustability. Certainly the method above is easy and if you get a valve with the right sort of flow properties with a nominal flow rate of about 125 lpm when half open it allows very good and easy control which does not seem to be too temperature variable. It seems better than trying to adjust a bleed valve at cracking open point which is very tricky to get right and far too sensitive. With the valve above I can easily adjust to 0.25PSI with a tiny turn. This is under the day to day variations caused by temp/press/humidity so is adequate.

I am beginning to belive that the solenoid map is only based on throttle position and RPM with no element of closed loop boost control on the ECU - otherwise the held boost would not change with valves, but it very obviously does.

However, there was a post a while back "Bleed valve only alters peak boost" so who knows! Works on my car anyway, and I don't see why it should be different.

HarryBoy

My car is a standard ECU MY00 with SS D/P and playing with the restrictor see's the boost go wild and oscillate with too small a restrictor and with a larger one the boost become more damped but progressivly less peak boost is held.

As standard I get quite a peak boost and adding a bleed valve alone raises held boost but puts the peak into the fuel cut zone, so trying to get a 15psi held boost does not work as it peaks and the fuel cut comes in.....

Hence my reasoning that a better damped peak with bleed to raise held might be the way for me to go with my car.

The only thing about the Dawes Device that concerns me (apart from the part throttle problem) is the lack of fuel cut. I have suffered from a stuck ball (could'nt sit down or walk properly for weeks!!) the boost hit 18 PSI with no cut. It should be possible to re-plumb the MAP sensor back in, I'll have to investigate.

Harry

john banks

None of the methods we have discussed involve removing the fuel cut unless you are bleeing the MAP line which I consider hazardous. I have hit 21PSI on my PPP with no fuel cut - I think it may take a little while at quite a high boost before it does it. Recent ECUs fluctuate the boost down by changing the duty cycle on the solenoid, hence usually avoiding the head through the windscreen fuel cut.

What I don't get is how a bleed valve no matter where placed will do anything different from a single restrictor valve - whatever you do with it will reduce the pressure on the wastegate diaphragm. Maybe with PPP it is different.

John Stevenson

This old chestnut again John I am getting bang on 1.2 bar having made a restrictor, must confess it was about the tenth attempt to get it spot on.
At star last weekend 254bhp/274lb/ft, the RR also plots the boost curve and it looked very healthy.

(MY98 PPP and Falkland downpipe.)

john banks

Yes John that old chestnut! I was never happy with restrictors as just when I thought I had got it right, for some inexplicable reason the boost would then wander off and my nice 1.2bar became 1.3 or 1.1. The closer I got to a good boost level, the more chance that after a few days that annoying boost fluctuation would return or the car would be slow. Now I am quite happy that a tiny turn of the valve will sort any wayward boost and then I can leave it alone until summertime. It gives so much finer control.

One night I was fiddling for hours - going out for a run - and each time you have to let the turbo cool a bit before turning off, then burn your hands on the bits, attack the poor Subaru rubber hosing with pliers to get the restrictor out. Then it would be senstive by a few PSI depending on where the damn thing was in the pipe. Then I would use the drill bit in my hand to shave off tiny bits to bring the boost down, and then find it had gone too low, have to go back home and get the soldering iron out again. Absolute proverbial pain in the neck. Took me a lot more than 10 goes and I never got it bang on like now.

Now it takes about 15 secs from flipping the bonnet catch to adjusting and driving away and you can do it with the engine running.

274lbft is very nice. A bit surprised the power isn't higher given that?

[Edited by john banks - 11/28/2001 6:55:34 PM]

john banks

This is my attempt at a diagram. The little dots (x4) show where I used heavy duty hose clamps (the two nearest the turbo outlet are highest pressure and most critical). Sorry no photo.



I used three lengths of new hose for the whole connection from turbo outlet to wastegate.

[Edited by john banks - 11/28/2001 7:25:03 PM]

WUZ

iTrader: (14)

Can I kill 2 birds with one stone?

Can I remove the restrictor and fit an electronic boost controller (HKS EVC IV) so I can run 1.05 - 1.1 bar with standard ecu?

God I hope the answer is yes!

Andy Tang, your input would be appreciated!

Russell

babber

All,

Two crap pictures of my bleed valve (one way) taken in the dark just now, in the rain.

I will take another tomorrow, cause it doesn't give my digi camera any justice





Cheers Phill C

Edited as the pictures were crap and out of focus and I removed one.

[Edited by babber - 11/28/2001 8:36:00 PM]

[Edited by babber - 11/28/2001 8:39:13 PM]

john banks

Thanks Phil.

WUZ, yes you can put an EVC IV in and run 1.2bar, but you leave the factory setup intact and it returns to it when you turn the unit off. Costs £4-500 though compared with £7 for a valve, and £25 for a Dawes MBC.

iain atkins

Hi John

I've ordered the same bits as you from pipemore yesterday (they just did a repeat of your order) and the bits arrived today.

Would it be OK to use this on a 97 with de-cat, induction and non-ppp ecu?

Cheers


Iain

john banks

Can't see why not. Just be careful with the boost. Your cutout will be lower than with a PPP. I would advise only setting this to standard levels at most plus up to 2PSI, and ideally get the fuelling checked on either RR, wideband lambda sensor, lambdalink or a Select monitor.

Obviously you are responsible for your own engine! But I am stating the obvious....

babber

John,

What I can't work out is how do you manage to be a GP, as well as gain all this knowledge on tuning Scoobies and doing all the work on it ?
Cheers Phill C

JFB

ith all the attention it gets, John's scooby must be with BUPA Platinum!!!!!!!!!!!!!!!!!LOL

Jerome

I wish I understood half of what he said so I could do the same!

john banks

I am just a bluffing but obsessional idiot. Always makes you look clever. Now where is my copy of, "How to bluff you way into medicine?"

dowser

Thanks John, you bluffing but obsessional idiot, you're a star

Now - who wants to buy 10 restrictors, variety of sizes, off me

Richard

HarryBoy

John,

Just finished going 'through the mill' with restrictors and bleed valve. For any combination of restrictor size and bleed valve setting the results where the same IE adjust restrictor for a damped boost, crack open bleed valve for 15 psi = result: boost hits 15/16PSI or so peak then drops back to standard 13/14PSI....

I did achieve a sustained boost increase of approx. 1 PSI with one combination with a controlled peak but it hardly seems worth it plus when it gets colder it will need resetting......

I might try your idea of a flow valve instead of restrictor or go back to the Dawes Device with restrictor.

Incidentally I don't see how a restrictor with the Dawes is going to work but I'll try anything once!

Harry

DaveMcC

I've been suffering from overboost on changing gear from 2nd to 3rd. Dealer was going to start the drill out/replace the restrictor game (this was the advice given to them by IM!). However, I chatted to the service manager about the idea of using the flow valve as per John, and he's agreed to fit it and set it up, and that it won't affect my warranty (they weren't very keen on messing around with the restrictors for some strange reason!)

So - ordered the bits from Pipemore (another duplicated order of Mr Banks!) at 3pm yesterday and they arrived in this morning's mail - now that's what I call service.

Also managed to get some 3.5mm internal diameter hosing from my local motor factors (it's braided as well), so just need to get the car booked into the dealer now (I know I could do it myself, but I don't have a boost gauge (yet!) and I value the warranty, so I'll let them play.

John, I presume as my MY00 is standard, it should be running 14psi and hence the starting point for the valve is about 6 2/3 turns open (using your start point of 5.5, plus 7 x 1/6th turn to reduce pressure by 3.5psi).

As a matter of interest, does anyone know what boost pressure the fuel cut triggers on a standard MY00?


Dave