Scott.T

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Paul_H,

The circuit shown above....

Scott.T

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Cheers John....
I also was thinking of an http://www.farnell.com/datasheets/2969.pdf. I think the current ratings will be OK.

David_Wallis

Paul,

Thanks for the photo.. I always thought the restrictor was in the pipe... but think mine may be different... I have taken some photos so I will post these when I get home from work and maybe someone can shed some light on this one...

David

David_Wallis

As promised...







David

[Edited by David_Wallis - 4/18/2002 6:56:19 PM]

Paul_H

David I am unfamiliar with your model year but your picture looks to me like a plastic hose joiner, not a restrictor - but as I say I'm not sure....maybe someone can answer your question?

This is what it looks like on MY99:

David_Wallis

It does look like that to me, but if you look at the size of the pipe from the turbo outlet, and then the one it joins to... the hole through the middle is quite small...

David

Scott.T

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David.....
As you have a 3-port solenoid I think you'll find the restrictor is in the bottom hose coming from the boost control solenoid, that feed back into the air-intake expansion box.

If that's the case then don't bother changing it as it's purpose it not the same as John and Pauls restictor (which is in the pipe leading to the Solenoid, which I think is a 2-port solenoid).

Making the hole smaller will reduce boost in your case as it will reduce the amount that is bled away from the actuator i.e if you blocked this pipe, no air would be bled, therefore you would only see 7-10psi depending on actuator strength.

From my experiences removing this hose or making the hole bigger made no difference. Although that was before trying the FCD.

I would just consentrate on setting it via the actuator tension.....


P.S What MY, as if Pre97 facelift I don't think you MAP sensor signals will be suitable for the FCD (see my post above).
[Edited by Scott.T - 4/19/2002 8:20:01 AM]

[Edited by Scott.T - 4/19/2002 8:21:40 AM]

David_Wallis

I am running a MY94 UK 5dr...

I think I may just try adjusting the actuator then...

Edited to say that I may run the circuit using a 7809 which should be ok?

David

[Edited by David_Wallis - 4/19/2002 9:32:27 AM]

Scott.T

iTrader: (2)

David,

Have you got the FCD connected, as I beleive the output from the MAP sensor is different to Johns. The MY94 uses a 2 BAR (absolute) sensor and the MY99/00 a 3 BAR (absolute).

You will be seeing about 4.4V for 13.9psi.
See Below for Pre97 MAP Sensor Values....



Not the 18-20psi that John will have at those voltages.

However - if you do find that it works, please let me know as I was going to adapt the circuit to allow for the higher MAP sensor readings.

john banks

How about using the other circuit I posted with a higher value zener diode?



Trouble is if you want to run a lot of boost you will have no fuel cut at all with a 2 bar MAP sensor.

[Edited by john banks - 4/19/2002 9:46:22 AM]

David_Wallis

Looking at the MAP VS V, I am assuming I cannot fit a 3 Bar Map Sensor??

as..

Boost (BAR) MapSens V MY98 MapSens V pre 98
0.0 2.29 2.6
0.5 3.03 3.5
1.0 3.78 4.5
1.5 4.52 ?
2.0 5.01 ?

Am i missing something or is the accuracy of the readings debatable?

David

[Edited by David_Wallis - 4/19/2002 11:42:36 AM]

Scott.T

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I think you've labelled your table the wrong way round.... Pre97 MY is 1.0BAR = 4.5V

Changing the MAP sensor will require an ECU re-map

[Edited by Scott.T - 4/19/2002 11:40:58 AM]

David_Wallis

Ammended..

A remap isnt possible on the old ecu is it?

I presume all that is available is ppp which is hard to get.. or a link / motec / pectel...

David

Scott.T

iTrader: (2)

Yep your right there....

I have PPP on my MY94, but this only gives just under 14psi (due to Subaru and Prodrive setting this as the limit on early MY's)

David_Wallis

I dont like the idea of no fuel cut, but I do like the idea of 16psi... maybe I'll have to settle for about 13 - 14.. what a waste on a TD05h (Finally found the label..)

Any ideas.. build the circuit and try it anyway? but at 14psi??

What is the standard boost, is it about 8-10psi??

David

Scott.T

iTrader: (2)

Standard boost is about 12psi.....

I may try and get hold of a 12V regulator this weekend, so that the ciruit can be run from 10V. This sould allow the current 4.4V limit to be lifted to the required 4.8V.

For now tho' you'd be better off with a Dawes or a Bleed valve if you want to run 16psi and maintain the fuel cut (16psi is about the max you will get if the standard fuel cut limit is maintained).

john banks

The original circuit I posted had an interesting quirk which you may be able to use. It did allow you to defend above 4.4V but after the "new fuel cut point" it let through 4.4V. This was off a 5V supply. You might think of a way around it.

Certainly I heard that the Links when mapped with 2 bar MAP sensors seem not to have a fuel cut. Seems odd though if they use the MAP rather than MAF sensor for fuelling/timing. I gather the MAF sensor can saturate as well on earlier models, which could mean beyond a certain air flow it will go progressively leaner.

Just a few ideas - not sure if they are significant. Needs some thought.

David_Wallis

I have just been emailing stephen done.. Orginally sent him a page that may have been of interest to him... however I mentioned changing my car to run the newer ecu post 98 I think... as they can map this... and thought it maybe a cheaper alternative than link tuning...

Do I need to use a dawes or bleed valve.. can i not just fit a restrictor... or will the ecu adjust the duty cycle?

David

john banks

A restrictor will change your boost but on the earlier model years I don't know exactly which one or what to do with it. However the ECU will adjust the duty cycle and kill your fun, hence the need for the circuit.

Alternatively, a Dawes can be used, but you need a circuit if you want to go over fuel cut.

A remap is undoubtedly superior to tacking circuits on fooling the ECU, although obviously more expensive.

David_Wallis

surely all I need to do is resrict where it measures the boost from... the nipple on the turbo?? And do I need the restrictor circuit if the fuel cut is set at 15... can i not just run up to 14.5psi or something...

David

Scott.T

iTrader: (2)

OK, thought it was about time I took some readings for a Pre97 MAP sensor, to see if the values 'extrapolated' by Chris (which I posted above) tie up.



This suggests that they do, as the Max reading I could acheive running the Prodrive Chip was approx 4.4V

Dave,

If you want to run more boost put a Bleed Valve between the turbo outlet nipple and the Boost Control Solenoid. If you get one from Forge Motorsport it's about £20.
Connect it up and crack it open 1 complete turn. This will give yout about 15psi (but a boost gauge would also be a wise move, if you havn't got one already).

David_Wallis

I have got a boost gauge... just not fitted at the moment.. if I take it to 15psi then I dont need the circuit do i?

David

Paul_H

This works right up to 5V so will work with all model years.

Defend point and fuel cut are independent of each other i.e. you can adjust where you start to defend, without this having an effect on the fuel cut level, and vice versa.

Full details here: http://www.scoobynet.co.uk/bbs/threa...threadid=78214

Scott.T

iTrader: (2)

Too many components to fit in my little box tho' Paul.
I'm gonna try an MC78L12 (small regulator) and a 4K7 pot (which I have spare) to drop the 12V down to 10V. Then run the LMC7111 from 10V. This should allow it to work up to 9.4V (Wow....), but I will be setting it at about 4.9V (to begin with)......

Scott.T

iTrader: (2)

David, if you take it to 15psi, I assume with a Bleed, then no circuit will be required as you are still under the standard fuel cut.

john banks

Isn't it a right royal pain in the *** to get these restrictors right!

Just sold my PPP ECU , so now on an AE801 until I get Tek 3 done At 1.05mm and 2.5 turns actuator boost was 20 PSI. At 1.2mm and 0.5 turns actuator boost was a wonderful and oh so thrilling (OMG it is slow) 14 PSI. I just can't accurately drill in between sizes, so I am going to leave the 1.2mm in and tighten the actuator until I get about 18 PSI. Gotta let it cool down (again )

I have the fuel cut lifter set about midway on the potentiometer, and it is shifting down the atmospheric reading by 15mV - so 0.15 PSI error should not be significant. Obviously I need to turn it higher without the PPP ECU as the fuel cut needs to be raised more.

I have to say at the same boost it is not as perky as a PPP ECU - from the butt dyno running 19 PSI it felt more like the PPP at 17-18 PSI - ie quite noticeable.

john banks

1.2mm and 4 turns on the actuator just makes it peaky at 16-17 PSI. Will go back to 1.05mm "and a bit" with the actuator only 0.5 turns. If that doesn't work I fit the valve as a bleeder or an adjustable restrictor - I've been here before and it gets boring, but at least this time I don't have to get bang on what the ECU wants or risk it dropping the boost.

Scotsman

iTrader: (3)

Can't you drop the Dawes back in John? (or I have taken all your tubes and ties?)

Rich

john banks

I could and may do if I don't get it right. But I don't give up that easily

Scotsman

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