john banks

That is the set I have. It missed 1.1mm for some reason. Why not run 1.0 with a jiggle - they don't snap if you are careful. You can always put the actuator back to standard - on most cars it probably makes no difference - on mine it was dropping boost - the only reason I fiddled. Also you may find that a shorter restrictor at 1.0 mm is equivalent to a longer one at 1.1mm?

Paul_H

I'll have a go, and will have to play off the actuator & restrictor. I did wonder about the length of the restrictor and made it exactly the same length as the original. I also wondered if drilling the ends larger would give a venturi effect and speed up the airflow through it.

john banks

Oh that's getting complicated though

john banks

Xavier sent me this email:

"I built a 0,8mm restrictor. Then I can adjust boost pressure with the FCD from 1 bar up to 1,35 bars. between 1 bar and 1,15
bar, oscillations appear, but from 1,15 bar up to 1,35 bar, everything is quite nice. Performnace I measured are similar to the one I measured with the bleed valve at the same pressure, except in 3rd and 4th gear where they are even better. Very great.
My feeling is that the twins stock solenoid/stock restrictor (1.2mm) are efficient between 0.8 and 1 bars. The 1mm restrictor is efficient between 1 bar and 1,25 bars and the 0,8mm restrictor is efficient between 1,15 bars and 1,35 bars. Great isn't it ?
I also made some tests on tightening the actuator : after 2 full turns, no performance enhancement (and even oscillations apearing) . between 0 and 2 full turns, performance enhancement is so little that it is not clear. I decide to keep mine at 1 full turn."

This is on a MY01.

HarryBoy

Drills are available from rswww.com

1.1 mm = RS 178-024
1.15 mm = RS 178-030
1.25 mm = RS 178-052

Sold in multiples of 5

Harry

Paul_H

Cheers Harry. My jiggling has got it down to 1.4 Bar at the moment, still way too high.

I discovered tonight that just fitting the fuel cut lifter on its own has raised my held boost from 1.0 (standard) to 1.1 Bar.

I've returned the actuator to standard, so that I can see the results of adjusting the restrictor size. I drove into work today with the new restrictor on - 1.4 Bar - very careful use of the right foot required! Not wishing to also drive home with it like this I changed it back to the standard restrictor - i.e. the engine completely standard, apart from the lifter circuit which is still set to defend at 3.4V from earlier testing.

I was expecting it to feel slow - but it didn't. Observation of the boost gauge reveals why - I've got 1.1 Bar held just from this circuit. The actuator is definitely returned to standard, I've been careful with this and definitely haven't lost count of the number of turns.

Seems like the ECU is fooled into believing that boost is low and consequently is not shutting the solenoid bleed.

HarryBoy

Hopefully, I'll get time this weekend to build John's original circuit.

Interesting you get 1.1 bar just with the FCD installed, this maybe, is all I will need to do to mine, don't want to push it too far!

Harry

john banks

You should only get a rise in boost if you had a peak before and the ECU was dropping back the held boost a bit - every car seems slightly different.

STOP THE CIRCUIT BUILDING! - NEW CIRCUIT - MUCH EASIER - Will draw it and post soon.

john banks

This is the new circuit. Only needs one wire on the board itself, the rest can be done by layout using tripad board and solder.

The 3.9V zener, 470R combo is the best of many!

You can turn the pot to about 1/2 way before there is a significant (ie more than 0.01V) effect on the 2.30 V atmospheric pressure reading. This allows a good 4-5 PSI raising of held boost on a PPP or standard ECU. There is even some adjustability of held bosot with the potentiometer, but it is not good enough to merit a boost dial on the dash - it will drop the boost rather coarsely after a few seconds at the value that the restrictor/actuator combo dictates.

Advantages to this circuit:
1. Easy to build
2. Not using op amp out of spec like my original design (only supposed to tolerate up to +0.3V above Vcc).
3. Some adjustability of held boost.
4. ECU sees a continuous smooth boost profile if that helps - means you do not need to defend from 3-4 PSI below highest held boost.

Disadvantages:
1. If you lift held boost by about 4 PSI to run 18-19 PSI, fuel cut will typically go up by about 5 PSI = 22 PSI, but given that some have run 25 PSI for months then this seems not to be too much of a problem.

Scott.T

iTrader: (2)

John,

I've just oredered the parts for the origional design. Do you think it is worth changing to the new design. Or will the old one work well enough as a set it and forget it solution ?

Chris.Palmer

Scott,

Don't forget our MAP sensors are scaled differently.

Would be interested in your results & will also post mine - if I ever get the missus decorating finished and am allowed to continue with the project

Chris

Scott.T

iTrader: (2)

Chris,

Was your scaling info correct, if so I'll use it as a guide.

john banks

Changing the zener diode to a lower voltage will lower the threshold where it starts to work - you might want to buy all the increments you can get and fiddle with the circuit on a breadboard with say a 4K7 to 220K pot to give a simulated MAP input voltage - Maplin do a nice range of zeners from 2.7V up.

I found the 470R variable was OK because it doesn't draw loads of current but is enough to get the zener working and gives the gradient quite crisp adjustabillity, so change the zener value first. Even if it dropped 1.5V - that would only be 3mA through the resistor.

Dr Hu

Hi John,

I have been following this thread all the way...I want to build this latest circuit....can you post the Maplin part numbers of all the bits you used (sorry if you have earlier)

plus you need a little box & a piece of circuit board I presume etc.......I have nothing apart from a Soldering iron/solder & wire.

Thanks....

Scott.T

iTrader: (2)

I'll check to see how these match up to the code in the chip, as I may be able to just modify the MAP data in the chip itself.

Chris.Palmer

Scott,

Would you care to expand a little on your last statement - it sounds rather interesting...?

Chris

Scott.T

iTrader: (2)

I've taken a copy of the code in the chip, and imported it into MSExcel.
I have some basic information on the addressing of the map, but although the addressing did match up, the conversion of the data didn't seem to match what I was expecting.

Using what you have alrady done I may be able to get closer to a solution.

The next issue will be, do I blow the new code into my current chip or build a piggy back version with 2 8-Bit devices (as the current 16-Bit device is obsolete).

Chris.Palmer

Scott,

Would be grateful if you'd share the info you currently have would be very interesting indeed - do you have a fix for the low RPM part-throttle problem

Hmmm - me have eprom programmer & an urgent desire to hack code.

Would prefer to keep original chip intact & play with another one - blowing two chips will be a pain in the @rse

Someone out there must have a few of the these old chips floating around for us to play with!

Maybe we should send out a Pre My 97 search party into internet land

Chris

john banks

Dr Hu:
Try Farnell instead as Maplin have very limited semiconductor selection

LMC7111BIN op amp
470R enclosed preset
Selection of 0.5W zener diodes eg BZY 3V9 is the one I used
Some wire, and a board to build it on eg Maplin JP52G Tripad board or just strip board with a one hole break along the middle for the chip - eg Maplin FL17T.

Test it all first before putting it on the car!

Scott.T

iTrader: (2)

Chris,

YHM....

David_Wallis

Where about is the standard restrictor located on the car?? Did you determine that the restrictor doesnt need changing?? and that I should just do a couple of turns on the actuator??

David

LG John

Ok, I've only read half this thread but from now on I think we should all refer to John as 'The Brain'

Bad_Mujo

James_PowerMad: Like John Banks said, can you give us more information about the EBC.

I'm also working on a PIC16F877 based EBC and programming in C. Right now it's just a port of John Banks code. Thanks John for putting up with my sometimes stupid questions.

Does anyone know how many RPM pulses the ECU gets per revolution? On older cars there might be 2 pulses.

Scott.T

iTrader: (2)

Is there a post anywhere with the Map Sensors Voltages Vs Psi for a post97 model i.e as per Chris Palmers Pre97 values.

I am building up 2 circuits. 1 for an MY94 and 1 for an MY97, and obviously both need to be calibrated for their respective MAP Sensor.

Cheers...

David_Wallis

I currently dont have the heatshield on as I was having problems with the lambda sensor... now replaced...

So I can do either.. last time my car was rolling roaded I was seeing 213bhp doh... with a dip in torque beetween 1500 and about 3000 revs..

for about 16 psi should I be aiming at a couple of turns on the actuator and what size restrictor...

I dont know about the turbo on yours... but do you remove the retaining clip of and then remove the actuator arm (Mine has a kink in it...) and then turn the end down two turns and then secure with the nut... am I unscrewing the bit two turns so that the actuator has to pull further or does it push and therefore want screwing in...

Sorry to ask so much...

David

Scott.T

iTrader: (2)

Shorten the length of the Actuator to increase boost (this holds the wastgate closed for longer).
remove spring clip an lift actuator rod from wastegate.
Undo the locknut, shorten the Actuator by 2 full turns, re-tighten locknut.
Re-fit to wastegate.

David_Wallis

Thats what I thought but you phrased it better... Whats the recommended size on the restrictor then??

David

Paul_H

Scott - As measured on my MY99

Bar Map sensor output (volts)
0.0 2.29
0.1 2.44
0.2 2.58
0.3 2.73
0.4 2.90
0.5 3.03
0.6 3.18
0.7 3.33
0.8 3.47
0.9 3.63
1.0 3.78
1.1 3.92
1.2 4.07
1.25 4.13
1.3 4.21
1.4 4.36
1.5 4.52
1.6 4.67
1.7 4.81
1.8 4.93
1.9 5.01
2.0 5.01

Scott.T

iTrader: (2)

Cheers Paul...

David_Wallis

ttt - restrictor size?? see above.

David