HarryBoy

Ray,

I have put some info up at http://www.geocities.com/harryboy_scooby/, hope it helps. My car is a MY00, so the pickup for the Dawes AFR should be the same as the DIY listed on my site.

Harry

Rikki 95WRX

Mikey

Your posts are a pleasure to read. I begun to despair when I saw the thread getting techie again, as I think you did.

I am not techie at the moment, would love to be some day and have great respect for those that are.

Mikey I agree with the grey area thing being a put-off - it stopped me from buying a Dawes. I haven't had time to sit down and read through it all and get to know how it works and with all due respect i think it would be quite a tough exercise as a lot of these threads are conversations in tech speak.

The idea of a cheap mod to give me some more driving pleasure is very appealing. Then I started reading about the requirement for an AFC etc etc and all the other variable factors and I couldn't be bothered.

MY95 WRX has a boost guage, It peaks at 1.1BAR and holds 0.9. If I had read somewhere that I could buy only the Dawes thingy (which one?), fit it on (any hole drilling, 1mm, 1.5mm - aaarggh!) and set it up so that the boost holds at 1.2BAR and leave it and it will be fairly risk-free then I would probably have got one - but I haven't (although an earlier post by John came close!)

*** This isn't meant to sound unappreciative or disrespectful to any of the techie guys, merely my opinion on the "Dawes thing". ***

Regards
Rikki

john banks

Rikki - find out where your fuel cut is and go 1 PSI below that, block off and disconnect the wastegate solenoid, don't do anything at all to the bleed hole. Fit a Dawes AFR meter or run on a select monitor or rolling road to check your fuelling. Job done.

john banks

Sorry double post. Stupid ISP.

[Edited by john banks - 2/13/2002 7:58:19 PM]

Ray T

Cheers Harry,

ray t

Rikki 95WRX

Thanks John....Leading on from you response...

a) do you know how I could find out the cut off on my 95 WRX? (I have a feeling it is 1.2BAR but i am not sure)

b) if it is 1.2 BAR does that mean I can only boost to 1.1BAR safely?

c) if so, I am peaking at 1.1BAR already - holding 0.9. Would I see any benefit from fitting the Dawes i.e. making it peak AND HOLD at 1.1BAR? Is this what it would do and would this be a significant difference in performance?

d) anyone know the exact conversion formula from PSi to BAR or Vice Versa

Regards
Rikki

john banks

1.2 is high for a 95. It is also based on time - I can hit 21 PSI quickly without fuel cut on PPP.

14.5PSI = 1 bar (NOT 14.7)

Need air fuel ratio to know fuelling is OK with smaller injectors or a check of things on select monitor - recommend this. But if it is an import you need to be quite cautious - select monitor in good operators hands will give you all you need.

Gridlock Mikey

Dudes,

Thanks for all your e-mails It seems i wasn't the only one out there getting slightly frustrated at the apparent difficulty of getting simple to understand info

If anything, it seems that out of approx 1,400 views, i would say at least 100 people are gonna do the Dawes thing (Yes I had that many mails ) God knows how many said that a combination of Johns views, Harry's web page and my standing on me soap box helped them understand the subject in more depth.

Someone out there even reckons they might be able to improve on the Dawes

All's well that ends well

Cheers chaps (and laydees )

Mikey

By the way, i'm gonna get me one

john banks

Improving on the Dawes would not be difficult.

GavinP

Rikki,

a) 15.5psi
b) Leaving the fuel cut alone, 14.5psi is realistic
c) Much steeper boost curve - feels like less lag - much quicker A to B
d) 1 bar = 14.5psi (I had also read 14.7psi at various places)

Don't enlarge the hole in the Dawes as you have a large turbo. You can always make it larger later if it is too violent for you!

Web page: http://www.netcomuk.co.uk/~gavinp/9296dawes.htm

Thanks

Gavin

[Edited by GavinP - 2/14/2002 11:43:03 AM]

HarryBoy

Gavin, glad you posted this, been looking for your pre '97 setup for the Dawes. Ok if I link to it from the page I have on MY97-00 setup?

Harry

catflap

Subzero im with yo on this

Cant wait till a get the daws

I bet the questions will flood in when we get them from the group buy.

HAY MODERATORS
how about a tempary Daws forum (just for a month or 2, so we can all post views, and info and questions while setting them up)

Would be a valued resouce for us

Gridlock Mikey

See that, that's a great Idea that is

Mikey

GavinP

Harry,

No probs - I'll add a link to yours - probably won't be until the weekend.

Any takers for doing a 97-98 one so we have a complete set ?

Thanks

Gavin

mega_stream

Woops what a mistake'a to make'a

Its all becoming clearer now.....just to add to the confusion though....do I want a standard, deluxe, race, or race deluxe dawes device

My ecu is the brown ae801, which is a good starting point (so I been told ) Along with my SS downpipe and Hiper system I should hopefully get some good gains then

I need a boost gauge then...

[Edited by mega_stream - 2/11/2002 5:04:11 PM]

john banks

I personally find that 99% of the time the air fuel ratio meter is reading safely. Only if I am on a high (18PSI) boost trash where I am driving on back roads using as much boost as often as possible - the sort where you would smell the brake pads cooking in the dry - does the sensor heat up enough to read lean. It doesn't mean you ARE lean. It could be due to the position of your lambda sensor.

I wouldn't cruise in a Scooby on German roads at over 150mph continuously - neither would I in an unmodded car cruise over 140mph - it is not stable enough over 130mph IMHO to make it safe never mind the possible risk of engine failure from sustained high speed cruising.

If going to altitudes over those that you would get in the UK I would also be cautious.

But other than that if your part throttle is sorted out the Dawes is safe.

BTW on my Dawes - 1/2 a turn is 1 PSI at 17-18PSI.

[Edited by john banks - 2/12/2002 1:16:00 PM]

john banks

I don't think the part throttle full boost issue is COMPLETELY resolved by the bleed just relieved enough for it not to be an issue in normal UK road driving or even brisk road driving. I don't know about cruising at double the UK speed limit. I think you would need EGT probe as well as knocklink and inlet temp monitoring to know for sure.

If you cruise at 150mph with Euro gearing that will be 6000rpm. At that point you will probably be making up to 15PSI if you are at full throttle which is likely. I would not do this for any time without knowing intake temperatures or having a Knocklink so is Lars really that paranoid? I personally think not.

At altitude, it will still aim for the set absolute pressure, so the boost pressure will have to increase. This will work the turbo harder and create more heat, and could result in excessively high temperatures, retardation, and possible knock.

There would be the same issues with a Link ECU or any electronic boost controller, or for that matter any engine mod unless it was tested or mapped to deal with these extremes. For use on UK roads I know my Dawes setup is safe. I have not tested it on the track, and would definitely want to measure intake temps and probably run no more than 17 PSI and drop it at the top end which the Dawes does not let you do.

Guess what my current plans are: - 1. source inlet temperature monitoring system and test at Knockhill 2. get EBC running which will allow me to adjust the boost by RPM accordingly.

Within limits the Dawes or other devices are safe - it is no the equipment it is knowing its limits and setting it correctly.

The fact is small capacity 4 cylinder engines are not good for high speed cruising - especially not those with the lack of high speed stability or aerodynamics of a Scooby.

I would trust the engine of our 3.0 litre Peugeot 406 V6 to cruise at 145+ mph for hours on end far more than the Scooby with a Dawes and barely adequate intercooler and inefficient hot turbo. Big V6s are just not stressed doing this in comparison IMHO.

[Edited by john banks - 2/12/2002 3:32:17 PM]

Lars

Subzero, it was not my intention to frighting you, I consider my Dawes set up as safe, and use the car every day from home to work, NO problems.
I do not agree that the Impreza is unstable on high speed, I have the bump steering done and the lift off kit that give me a bit more caster, maybe this is the reason. I often do high speed crusing with 130 to 140 mph. If you drive in Germany during night time it's no problem and the car is stable.
I measure the intake temp. and its normally newer above 35 deg. ( standard TMIC) When you slow down and loose the cooling wind, temp go up 5-10 deg. I'm OK as long as I stay below 40 - 45 deg. But I'm still a chicken and will remove the Dawes before my skiing vacation. By the way I have a 1 mm bleed hole and do not have any part trottle boost problems. Subzero go and by one, you will love it.
My car is a MY 99 and has done nearly 40K miles without any problem, I do high speed crusing when possible, and as many track days as possible.

[Edited by Lars - 2/12/2002 4:22:17 PM]

john banks

I'm not saying anyone's car will blow up or they have damaged it. Unmodded cars have let go after sustained high revs/speed cruising, so I would be wary personally crusing much over 130mph until we know more about it. Just my opinion and my personal threshold. And most German prestige cars are in a different class IMHO for cruising at these sorts of speeds in terms of stability - that is after all what they do best, rather than a car designed in a country where speeds are limited to 112mph. I am no expert on the issue, just my personal opinion and choice!

My car at 6000rpm is making about 14-15 PSI. That is easily over 3 PSI more than standard - hence the increases in power! Now high speed is presumably good for cooling, but when I have modded the car and have not collected data myself or seen others date at sustained running at high revs on a track or autobahn I am not going to do it unless I have that info first. Just my personal approach I am not saying it is "correct" or indisputable. Same approach with altitude. The ECU does measure atmospheric pressure using the pressure sources solenoid control valve, and I would be much happier running the standard or PPP ECU at altitude.

The OEM boost control is a bit lame, but is researched at a cost of millions to be safe in all environments. I am happy to take advantage of it and within certain operating parameters (ie fast road UK use) up the boost considerably. If my engine lets go then so be it, I know I am taking more of a risk than running it at standard boost levels and eating into Subaru's considerable safety margin. I think I would be kidding myself if I believed otherwise. You want the toys you take the risk. It is a risk I am very happy with in the situations I use my car. Just my 2p I am not saying I am "right" and everyone else is "wrong" - it is more a sliding scale of risk and some degree of uncertainty an dhow much you want to live with. There are no simple right and wrong answers and if you look for them you will be disappointed.

Gavin just seen your reply - whilst I hear what you are saying no one can say for sure that boost is nothing to do with it. I gather we have no definitive answers on high speed failures yet just a load of theories? As you say higher boost will not help the problem.

Lars' data on his intake temps is encouraging that the intercooler and boost are OK at speed though.

If you can't deal with risk don't mod your car and always have a warranty. It is a valid option! Buy an M3 or something!

[Edited by john banks - 2/12/2002 5:16:25 PM]

john banks

Std boost at 6000rpm is about 11PSI, up to 12 typically with a downpipe - see the dyno site - Powerstation has some boost plots. The standard car usually makes 12-13 PSI unmodded. Even at 6000rpm I am making 2 PSI more than the MOST the standard car gets.

Maybe your car is different, but my car is on a different plane boost wise from standard - it is making 5 PSI more in the midrange and 3 more at the top end compared to an unmodded car - hence why it makes about 20% increase in peak power over standard.



[Edited by john banks - 2/12/2002 5:55:34 PM]

john banks

As my car is I will give it as much boost as often as I can on a back road and you know what that means I have absolutely no concern about that at all. Trying to get high boost at 10000 ft like a guy on I-club was talking about or running 3 PSI over standard at 6000rpm without data for a long time concern me, but they are on a different planet stress-wise to the motor! Any sane person would say I abuse the nuts off my engine, but I try to do it within safe parameters and try to warm and cool it sensibly.

I am not at all concerned up to 130mph or off a track. On track I plan to drop the boost - one way of doing this with the Dawes setup is to loosen off the acutator which I already tightened. Then run 17PSI in the midrange and see how we go - ie drop 1-1.5 across the range.

[Edited by john banks - 2/12/2002 6:06:17 PM]

john banks

BTW guys don't be so worried about disagreeing with me I enjoy it - sharpens the mind. And I only argue for the hell of it most of the time to understand things better. And NO-ONE on Scoobynet has yet managed to **** me off. There are some about who are so prickly to deal with you just don't go near any of their posts

I don't want to confuse anyone or worry Dawes newbies, but some people think I should not be encouraging people to fit Dawes when they don't consider all these issues, and several are worried about the developing interest in fuel cut lifters.

Gridlock Mikey - I am not intending to patronise you by saying this: From reading many of your posts I think you like to see things as cut and dried/black and white/true or false when it comes to fitting things on your car, and I personally appreciate your approach as it cuts through a lot of bull****. I can appreciate that you may not want to learn the ins and outs of the thing, but for "The minor guild of driveway tuners" of which I am a small part, you do need to know what you are doing - and by that I don't mean how to physically install a Dawes which is laughably easy. I would be reluctant to just tell people to go and do something because it worked for me. If you understand it you know how to resolve issues if they arise and the whole thing is safer. Please consider an area you know a lot or a fair bit about and then consider how difficult it would be to tell someone or give someone a cut and dried answer to a complex question with many factors and variables - some unknown. No area is simple enough to reduce to this level - if you do you miss the point. Hence there are always conditions and ifs on every opinion - otherwise it becomes dogma issued by "gurus" I really hope you are happy for me to talk so freely.

For me a lot of the enjoyment of all this is in learning about my car and making it better.

************************************************** ******
Having said all of the Dawes is safe and effective on MY99/00 up to fuel cut with a 1-2mm bleed hole. Dogma there you go.
************************************************** ******

There may be other situations in which it is also safe but I have not personally tested them. You may not get back as much as you invested. Your home is at risk if you do not .... sorry wrong phrase... "Your leg will fall off and you will die unless you do what I say sir...."

[Edited by john banks - 2/12/2002 10:08:16 PM]

john banks

Faster than my secretary.

I thought you were Gridlock Mikey coming to punch me for being a patronising bar-steward.

[Edited by john banks - 2/12/2002 10:20:32 PM]