Paul_H

David - be careful with the restrictor sizes. A small change in restrictor size has a very large effect on the held boost. My MY99 holds 1.0 Bar with the standard restrictor (1.2mm?)

Changing to a 1.0mm restrictor resulted in 1.5 Bar, much more than I want, or is sensible to run on a small turbo.

I've got the restrictor now accurately drilled to 1.15mm but haven't run it yet, I will post the results soon.

If you are going the reduce the restrictor size then be safe and do so in 0.05mm increments. You will probably have to experiment with your individual car.

David_Wallis

so the smaller the hole the greater the boost..

What size is the standard restrictor... over 1mm I assume..

I have some 0.8mm and 0.6mm welding tips as mentioned before but think these may be over the top..

National say they cant do samples on the op-amp... looks like im off to farnell..

David

hmhaga

How do you splice into the wiring to the ECU? I hate DIY modifications that look like...DIY modifications That's one of the reasons the dawes device had to go.

C h a z

I admit it, I am a dwarf standing amongst giants of the Subaru tinkering collective. However, about a hundred years ago when I first got my Scoob, and joined Scoobynet. I suggested adjustment of the actuator to achieve power gains and was promptly shot down in flames. Hmmmmmm
This all looks like a good way forward. If Rich wild is reading, is your car holding together at the new higher boost levels?

David_Wallis

If you dont like the look of DIY Mods then I wouldnt suggest doing it, and I suspect john and others will not tell you exactly where to pull 5v from and which colour wire you need, just so that they cannot be blamed... but can point you in the direction of a wiring diagram...

Also as far as I am aware adjusting the actuator is an easy way of adjusting the boost, within its limits, but you can only adjust is as far as the fuel cut will allow... +2 psi???

Please correct me if I am wrong...

David

Scott.T

iTrader: (2)

Adjusting Actuator make very little if any difference if the above mentioned circuits are not fitted to the MAP sensor output.

The ECU will just alter the duty cycle of the Boost Control solenoid in order to maintain standard boost.

These circuit fool the ECU, hence the duty cycle will not change hence actuator adjustment will increase boost. At the same time the circuit will cause the boost cut to be lifted.

Without this circuit the only way adjusting the actuator will make a difference is if it's getting weak, or wasn't set correct to begin with.

David_Wallis

bl00dy farnell £10 minimum order.... ended up buying 2x op amps a pair of cable cutters (not wire cutters) and a pair of welding gloves..

David

Paul_H

If you look at the above image you will see that I have my lifter circuit on a multiplug, it plugs into a corresponding multi-plug on the loom, by the ECU. I can easily remove the lifter just by disconnecting the multiplug. I can then insert the small "dummy" connector shown above, which connects the MAP sensor wires together and thus the MAP sensor wiring is returned to standard - in seconds.

I posted earlier that I had found that my boost had increased just by fitting the lifter circuit. I have done some back to back runs, using the standard restrictor, and with the wastegate actuator adjusted as standard.

As standard my car holds 1.0 Bar. With the lifter removed, and the dummy connector shown above in the circuit, I get.....1.0 Bar, exactly as expected. Simply by removing the dummy connector and connecting the lifter circuit, my held boost rises to 1.1 Bar. If I remove the lifter, insert the dummy connector again...and it's back to 1.0 Bar.

I can't comment on other cars, all I can do is report honestly my findings on my car. I get a rise in held boost from using the lifter circuit alone.


I have the lifter defending from 3.4V, i.e. quite low. I believe that, on my car at least, the standard held boost is controlled by the ECU via the solenoid, and that because the ECU is receiving a signal implying that boost is below target, it is not closing the solenoid bleed, and I get extra boost.

I can easily demonstrate that this is the case if anyone has any doubts!


[Edited by Paul_H - 4/12/2002 8:48:51 PM]

[Edited by Paul_H - 4/12/2002 8:51:31 PM]

Paul_H

On my MY99 I have found that a 1.15mm restrictor results in 1.2 Bar of boost.

Paul_H

On my car, restrictor sizes work like this, once the control of the ECU/Solenoid is removed by a lifter circuit on the MAP sensor:
Your car may be different, proceed with caution!

Restrictor size===Bar===PSI

1.2mm===1.1 Bar===15.95 PSI-----Tested
1.15mm==1.2 Bar===17.4 PSI------Tested
1.1mm===1.3 Bar===18.85 PSI-----Tested
1.05mm==1.4 Bar===20.3 PSI------Interpolated
1.0mm===1.5 Bar===21.75 PSI-----Tested, unintentionally

PeterPerfect

Ok John, Paul, James...whats the current 'recommended' FCD circuit to use on a MY99 ECU ?
Is it still the one John B posted on Tuesday, April 09, 2002 22:29 ?

Thanks

Scott.T

iTrader: (2)

Just built the origional circuit with the intention of fitting it to an MY94. Settings will be 4.1V (11.6psi) and 4.8V (17psi) respectivley for now, as the pre97' is mapped differently.

Unfortunatly I tracked it out wrong on the strip board and got one of the chips supply rails swapped.... hence 700mA was drawn and the chip went 'POP'.

Have since re-tracked it and shall try bench testing it again tonight.

It's quite neat tho' and fits into a 50mmx35mmx17mm box.......

[Edited by Scott.T - 4/16/2002 7:49:51 AM]

David_Wallis

scott... are you saying that the 94 (same as mine) shouldnt run above 17psi??

I was aiming for about 16psi, do you think that this will be too high?

David

Scott.T

iTrader: (2)

Early MAP sensors (UK) only work up to about 18.5 psi (see Chris.Palmer post on Page 3).
16psi should be alright, as long as the fuelling is OK.

I'm aiming to run about 15-16psi, but then I have a PPP ECU.

David_Wallis

What are the actual differences with the ppp... boost hoses... (not too bothered about.. as I am looking at making my own fmic...) exhaust and filter... (have a hks air filter and hks exhaust.) are there any other differences?

Does the ecu not just have an increased boost level and fuel cut... and possibly different timing and fuel levels throughout the rev range???

I thought john said he had tried @18psi with ppp and without ppp... I know his is a later car, but is there any advantage having a ppp when increasing the power this way?

David

Scott.T

iTrader: (2)

Early PPP increase boost to just under 1 BAR (13.5psi - 14psi ish).
But also remapped the ECU for 97/98RON fuel.

Pre97 PPP was ECU, Backbox and Ramair filter.

It feels alot different to the standard settings of 11-12psi. Certainly feeld more lively lower down, and feels more than an exta psi or so higher up.

The figures John has been quoting are form MY99/00 which run higher boost levels than any other MY's (probably due to the smaller turbo).

Paul_H

Peter, there have been a number of circuits posted, it perhaps is not easy to decide which one to use if you have not been involved in the development or testing of them.

You could probably choose any one of them. Some have more components, some have noticeably less - and are therefore easier to build, and cheaper, some have different characteristics.

My personal knowledge is limited to the first circuit posted in this thread: http://www.scoobynet.co.uk/bbs/threa...threadid=78214 because that is the one that I have in my car, and have had for about 2 months with no problems at all. I don't need to try out the other circuits because this one works for me. It suits my purposes because I can adjust the defend point and new fuel cut independently. The other circuits are also equally valid. I think it would be difficult to be dogmatic without gathering them all together and doing some comparison testing, which I can't see happening, and I'm certainly not interested in a "my circuit is better than yours" scenario... frankly I just want to get on with driving the car now! So maybe do some research by reading the threads again and pick the one that suits your purposes the best.

PeterPerfect

Thanks Paul, I'll have yet another read of this excellent thread
Its great that you guys are contributing this sort of information...especially for those who cannot/will not buy a PPP

I assume you have taken the +5v off the throttle position ?
My preference is for a 'hard coded' defend and cut point....that way I may not be tempted to dial in more boost
I WILL build one of these...just not sure which yet. In the mean time I'll keep enjoying the Dawes on my MY99 !
Pete

Paul_H

Peter, I believe that John has used the ECU 5V power supply to the TPS successfully.

I have used a voltage regulator on my circuit, probably unnecessarily, I used an LM7805 as shown in the circuit diagram, datasheet can be downloaded from here: http://www.fairchildsemi.com/pf/LM/LM7805.html
It's very simple to use, only 3 connections - 12V, ground, and 5V output to the circuit. Costs about 49p.

I know what you mean about being tempted to up the boost, but if you're sensible enough to realise the dangers then you can also be sensible enough to resist too? I've had mine up to 1.3 Bar but have decided to turn it down a bit in the interests of longevity. There's not a lot of point going over 18-19 PSI on my MY99 (small turbo), there's no more gains available, only problems waiting! I have found it useful to be able to adjust the settings after finally deciding how much to run.

Scott.T

iTrader: (2)

Please Help......

OK so I've built up the origional circuit and am trying to set it up correctly for the Pre97 Map sensor.

I have managed to set it as follows, but have a few concerns with respect to the time it is taking to come out of the 'Step' i.e I can set it to stop ramping at 4.1V, but it seems to be taking far to long to catch up....(see below)

I/P-------O/P
4.00V----4.00V
4.10V----4.07V
4.20V----4.07V
4.30V----4.07V
4.40V----4.07V
4.50V----4.07V
4.60V----4.09V
4.70V----4.12V
4.80V----4.15V
4.90V----4.20V
5.00V----4.26V
5.10V----4.33V
5.20V----4.42V
5.30V----4.50V

Maybe I need to change the pots to a different value, as my concern is that it will be pushing the 'Fuel Cut' far to high.

See Below for Pre97 MAP Sensor Values....




[Edited by Scott.T - 4/17/2002 8:57:19 AM]

David_Wallis

Is the restrictor in the thin pipe coming off the outlet of the turbo housing and then across to the brass coloured thing on the inner wing with three pipes on it?? If it is, which I think it is then I have machined a new one up last night out of a piece of nylon, just need to drill it now... Will post pics soon.. Have all the bits to make circuit... will be builing on a breadboard first..

David

Scott.T

iTrader: (2)

Come on guy's help me out (see above).... I've already had to re-lay the thing out twice due to be messing up the layout design + assigning the pin number incorrect.....

Which pot adjusts what ?

David_Wallis

I haven't built it yet so cant really help... which circuit have you built??

David

Scott.T

iTrader: (2)

I think 1 of me chips had died, so I'm gonna take the oppurtunity to re-build it (due to my earlier lay-out error).

Just ordered some more parts from farnell and due to the minimum £10 order I now have enough bits to build about 4.

If anybody wants the parts for the circuit on page 1, e-mail me and we'll sort something out.

[Edited by Scott.T - 4/17/2002 1:17:38 PM]

john banks

Sorry Scott, been on holiday. Looks like a circuit/chip problem - you should get the sort of response I posted on page one. Trouble is the 0.3V over Vcc offficial tolerance on the op amps - this seems to be about the best around. It does seem to work higher though. The other limitation is the voltage drop across the diode limits the upper notch point with a 5V supply to about 4.4V.

Scott.T

iTrader: (2)

Perhaps I won't bother rebuilding then as with a 4.4 max notch it's only gonna be about 13.9psi on a pre97 (see above chart).

This is probably bang on what it's running with the Prodrive Chip, as it holds at just under 14psi on my gauge.

Perhaps we need to run it off 12V instead of the 5V supply.

Scott.T

iTrader: (2)

Suggestion for 12V Regulator required (can't be ar5ed to trawl through the farnell catalogue).
I can then pot/div this down to 10V and run the LMC7111 of a 10V as opposed to a 5V rail.

This should then allow me to switch at 4.8V.

IF YOU HAVE A PRE97 THEN THEN A MOD TO THE ORIGIONAL CIRCUIT (shown below) IS REQUIRED, DUE TO VOLTAGES BEING HIGHER i.e 4.4V = only 13.9psi.




[Edited by Scott.T - 4/17/2002 10:43:47 PM]

john banks

http://www.crownhill.co.uk/item260.htm

Paul_H

Scott, to avoid confusion can you post which circuit you are referring to, preferably by posting the circuit diagram.

Paul_H

David the restrictor on my MY99 is in the hose between the turbo outlet and the T-piece. Unsure about where it is on earlier or later cars.

Edited to add - just spotted this picture

Be very cautious, see earlier warnings about small changes in restrictor size having a very large effect on boost levels.

[Edited by Paul_H - 4/17/2002 11:54:42 PM]

[Edited by Paul_H - 4/17/2002 11:55:19 PM]

[Edited by Paul_H - 4/17/2002 11:56:08 PM]