Richard Curtis

Just a couple of questions before I fit the thing -

Throughout peoples experimentation has anyone tried taking the feed for the Dawes from the unused manifold nipple instead of the turbo?

Also after reading through all the other threads - I am still a bit confused about what you do with the pipe that comes off the T piece between the turbo and actuator - the pipe goes off to the area near the boost solenoid. How have you connected this? Do you need to connect it to somewhere to keep the fuel cut in place?

btw - my cars a UK97

Advice appreciated

Cheers
Rich

john banks

Disconnect it and put a screw in the end to seal it - fuel cut is controlled by the MAP sensor which you are not fiddling with unless you are called Harry Take the T-piece out. Then connect the Dawes but don't use the original hose with the restrictor in it.

If you run off the manifold you will have a longer run of hose, but probably similar results. Don't think anyone has tried it, but short hose runs seem best.

[Edited by john banks - 12/30/2001 6:53:03 PM]

HarryBoy

Those MAP sensors can be tricky little blighters to identify!

Somebody posted that the SAAB owners connected the Dawes to the manifold but I have not tried this, John?

Harry

[Edited by HarryBoy - 12/31/2001 10:53:33 AM]

Richard Curtis

Thanks - think I've sorted it now , dawes is plumbed in and seems fine.

couldn't pull the T-piece apart without fear of breaking it so i've blocked up both ends.

I got a copy of the link ECU manual and all the bits are identied there - the pressure sensor has a seperate pipe to the solenoid which i didn't realise until closer inspecion of where all the pipes were going - sorted now though.

Thanks again

GavinP

What do you think of it Richard ?

We have a few early (94-96) and late (99/00) cars but very few inbetween....

Would be interested in your comments...

Thanks

Gavin

Richard Curtis

Gavin,

I an still trying to source a boost gauge to set it properly so I've been very cautious so far - just basically checking installation and that it functions ok.

I set it a few turns from its minimum level for now which seems to give less overall boost than stock (just to be safe). However the spool up is quicker and occuring at a lower rpm, the car does now seem smoother to drive.

I can only tell from driving and listening to the turbo - but I don't think i have any overshoot at all at the moment. I still have a cat fitted on the downpipe and i think this is helping in this respect, also, I ordered the race spec dawes controller which promised faster regulation, this may also be making a difference.

I hope to be a bit more adventurous next week and wind it up a bit when i get a gauge and have built a lambda indicator to check fuelling.

I've also got a unichip on the way which i hope i can get set-up with boost levels similar to john banks later this month.

I'll let you know how things progress.

Rich

john banks

The unichip would help by tightening up your fuelling and ignition advance, but probably not much I reckon - it is boost that makes these cars quick and the stock ECU seems to handle timing and fuelling pretty well. However, the Unichip may also help by raising your fuel cut allowing you to run 17-18 PSI more happily.

[TECHIE BIT ALERT - IGNORE IF THIS MEANS NOTHING SORRY IF PATRONISING (!) But there may be cheaper ways to do it - apparently the PPP ECU may just be a MAP sensor remap by 2 PSI at the top end, raising fuel cut and held boost, and if you happen to be in IT like most Scoobynetters and happy with dealing with PICs it may be a little project for you - you would need a PIC with AD and DA conversion on board and you would let the signal pass through unaltered up to say 15PSI. 16 PSI would become 15.5, 17 PSI would become 16, 18 PSI would become 16.5 and 19 PSI would become 17 PSI for example.]

However, this might all be unnecessary as no one on the stock ECU seems to have found fuel cut yet. Come on guys - get them checked for fuelling and timing and let us know where it is. If you can run 17 PSI happily without being near fuel cut and all is well, I personally wouldn't bother with a chip if you are choosing to run a Dawes.

[TECHIE BIT ALERT Also in the absence of a boost gauge you could tap into a MAP sensor line and check the voltage on a DVM. 0.88V is -1.0 bar 4.84V is +1.8 bar.]

Edit to say fuel cut is very possibly different on different model years.

[Edited by john banks - 1/1/2002 9:40:55 PM]

Richard Curtis

John,

I've bought the unichip secondhand and hence a bit cheap, I'm hoping I can get the fuelling spot on with a RR session and like you said no fuel cutting probs. The other way by putting a bleed in the pressure sensure line i thought was a bit dodgy.

I dont know what the trip value is for the standard 97 ECU but I think it tripped (sudden loss of power) when I tried playing around with the configuration. I had the dawes on the manifold going direct to the actuator and also kept the solenoid venting the boost to the intake (from the turbo nipple). Maybe there was too much lag in the dawes operating on the manifold or some other weird interaction - who knows.

Anyway - Changing to your configuration gave no probs at all.

Also, thanks for the tip regarding measuring boost - Is the pressure signal linear between the values you stated?

john banks

Apparently it is linear - use a high impedance voltmeter - ie a digital one of reasonable accuracy. 3.71V would be 1 bar 14.5 PSI. 3.99V would be 1.2bar 17.4 PSI by my calculations, and when I checked before it tallied with the error I knew my gauge had and I had between 4 and 4.1V.

So maybe consider aiming for 3.8V held at 3000-4000 RPM for now?

Obviously I have to also recommend you check your fuelling for safety.

Agree a bleed or a resistor is a bad way to change your MAP voltage and would transform the result across the range which is probably "a bad thing".

[Edited by john banks - 1/1/2002 11:18:45 PM]

HarryBoy

John,

I thought we had established fuel cut was at 1.2 bar (17.5 PSI) on the stock MY00 ECU? My experience with a bleed valve on the stock setup backs this up.....

Also, if PPP is just a MAP remap at the top end how come your car gets 17PSI at 2500 RPM? Does a fully decatted system give you this?

I have the SS D/P but only get around 10PSI at 2500 RPM......


Harry

john banks

Don't know why. On mine, time and again if you floor it in a high gear from low down boost is already >5PSI by 2000rpm, about 10 by 2200rpm, 18 by 2500rpm. This is with a Magnex/Falkland twin dump dp, ITG panel and PPP(STi decat) centre and PPP backbox. It may be slightly later now I am running some bleed, but time and again I can get over 15 PSI at 2400rpm. Can't think it is anything to do with the PPP ECU. Anyway, perhaps this is why my 53-73 times in 5th are so good. Can't see why yours doesn't do the same?

Re cutout - is it actually fuel cut at 17.5 and have you experienced it? How long did it need to be there? Or was it a previous setup and the solenoid started reducing its duty cycle and made the boost oscillate more smoothly than fuel cut?

I would want to be running day to day at least one PSI below fuel cut if set up in freezing conditions - preferably a bit more.

HarryBoy

HI John,

I am sure it was fuel cut...sudden loss of power...me heading for the windscreen.

Standard setup with bleed valve in line to duty solenoid.

Peak boost only needed to be at or around 1.2 bar for a second or two before it occured.

Harry

SPEN555

Harry/John,

I recently stretched the spring on my device and re-adjusted the device. I had it at 17PSi in fourth and I thought I would just check fifth. Fifth showed 19PSi and it held this and I got no fuel cut or sudden drop in boost. I happened to have a Legacy GT behind me (I think they are twin turbo and 280bhp) and I was leaving him until I backed off LOL!

I didn't want such high boost in fifth so a few adjustments later and I am now seeing 17PSi in fourth and fifth gear.

p.s. I too have PPP ECU.

Damian.

john banks

I stretched my spring as well to put it more in the middle of its range. I am surprised how consistent the boost seems to be day to day. I would hope you would leave a B4 or GTB if you are making similar power but weigh a fair bit less I have kept with a 996 Carerra 2, old shape M3 and an M-coupe recently

And yes they were booting it - you could hear them revving the nuts off their machines!