ScoobyJawa

Hi all,

As some of you know both Scott W and I have both had a Dawes fitted to our cars for just over a month now.

Got some fine tuning questions to ask.

1. I seem to remember reading that the shorter the tubing used the better? Is this the case, should the tube be as short as possible without it being kinked?

2. Sure I read somewhere about physical location of the dawes. At the moment it goes above the coolant pipe and as such is sort of half way between horizontal and vertical, is there any preference for it to be fitted either full vertical or full horizontal? Also it rests against the coolant pipe which means it can get quite hot, is this wise and can it affect the operation of the Dawes?

3. Both scott and I are now holding about 1.1 boost on our defi gauge, however it does sometimes peak which the defi shows as 1.2. I thought the dawes shouldn't peak, it should just hold what boost it goes up to, would this be cured by doing either no's 1 or 2?

4. Final one When full boost is achieved sometimes the needle on the gauge can fluctuate slighty, is that normal or again is this another thing where doing 1 + 2 would sort?

Thats about it, just also wondered about the fuel cut. Obviously 4th and 5th give the most boost so does this mean that in the lower gears the fuel cut is lower or is it still at 1.25ish (MY99+)?

Thanks in advance for any pearls of wisdom

Cheers
Neil.

HarryBoy

Hi Neil,

what model year do you have?

I have put some pictures on my web site on how I mounted it in a vertical arrangment for short tube connection see: http://www.geocities.com/harryboy_scooby/ there is also a link to Gavins's page half way down if it's an 92-96 car.

I had mine tie wrapped to the coolent pipe as well, not sure if it is better in the vertical but sense says the ball should center/seat better in the vertical plane than the horizontal.

I get peaks as well but no more than 1 psi or so. Can be dependant on temperature, when it's cold it peaks slightly more.

I don't know why the boost is fluctuating as you sy it could be the length of tubing.

Your fuel cut remains constant it's not dependant on gear.

Harry

ScoobyJawa

Hi Harry,

Cheers for the reply. Mines a MY99 scotts is MY00.
Judging from your picture on your site those hoses are just as long as ours only ours are more equal on each side of the dawes. I noticed in your picture in the "experiences" thread (http://www.scoobynet.co.uk/bbs/threa...threadid=49691) you indeed have the dawes against the pipe, ours is similar but over the top and cable tied to it.
The peak as the defi reads in kg/cm2 (I think, ie almost in bar) is 1.2 and we hold 1.1 (is that a difference of about 1.45psi?)

I thought that about the cut too, thanks for confirming it

The flucate is only slight, ie it wobbles either side of the pressure marker on the gauge but it can be noticable, and other time hardly do it at all, but I thought the dawes should eliminate this?

Cheers
Neil.

mega_stream

Neil

Did you find any inprovement fitting the Dawes with it default setting? Mine arrived yesterday, not fitted it yet though.

Are you going to Brands on Sunday?

Cheers

John

SPEN555

Scoobyjawa,

I have my Dawes set up exactly the same as yours with the hoses shortened as much as possible and this leaves the device straddling the top of the coolant hose. It also means I have approximately equal lengths of hose either side of the device.

I have often wondered whether the set up HarryBoy has on his car would produce better results? Has anybody done both?

p.s. I too found the coolant hose to be hot as it made my Dawes hot enough to the point it gave my finger a blister when adjusting to the correct boost. LOL!!!

Damian.

ScoobyJawa

John,

the dawes in standard setting is terrible It will make your car boost less than OEM When I fitted the dawes on its standard setting the boost held 0.7 bar In other words you will need to fit it and then adjust. Once adjusted though the difference is phenomenal

Damian,

LOL - yeah, I've got a few burns too from playing when hot I believe its an occupational hazard
I am going to try and see if I can shorten the hoses further, I think I can and run the dawes under the coolant pipe.
I think the picture on Harrys website is the best way to do it so far, as the picture in the link I put up IMHO uses far too much hosing.

Therefore I think I'll have a play tomorrow and see what happens.

Anybody else got any thoughts? T-UK? John B, Cossie Convert etc?

Edited to say not sure the pic is still there in the link I put up - printed it off a while ago. The pipe from the dawes loops to the wastegate Harry can you confirm? Which way do you have it now?

[Edited by ScoobyJawa - 2/22/2002 8:26:18 PM]

HarryBoy

Hi Neil,

1.1 Bar to 1.2 bar is about 2.5PSI (14.5 PSI to 1Bar). That's more than I see.

Have you drilled out the bleed hole? (not that I think it will affect the boost 'wobble')

I stretched the spring on mine, about 1/3 extra in length, this moved the adjustment for 15PSI a couple of turns down IE: I need to unscrew the Dawes by about 2-3 turns. I wonder if the spring is too compressed, in standard form you need to wind the Dawes right up to get to 15/16PSI......just a thought.

And Yes, in my original setup I had a big loop of hose from the Turbo nipple to the dawes and then another loop to the wastegate. JB suggested the shorter vertical mounting method, and it did help reduce the peaks a fraction but it was hard to tell.

Harry

john banks

The bleed does affect boost wobble and peak - more bleed = less of them. I run 2mm but my actator is tightened too. I run mine vertically and then the outlet hose is tied over the top of the coolant hose so the Dawes itself is not in contact with the hot hose, but only about 0.5-1cm away - close enough to be secure but no so close to be hot. I also use rather more rigid hose which helps positioning a bit. Not sure if any of this except the bigger bleed makes much difference!

Occasional wobbling happens to us all But I do not see a peak ever higher than 0.5 PSI in any conditions Scotland has produced so far this year, and it never shifts more than 0.5PSI from set point from -5 to + 15 degrees C so far, and the shift is not always the direction you predict - on some warm days I see 18.5, today when snowing it was about 18. Very progressive fun in the snow today on boost. If you are unhappy, increasing the bleed some more can help. I think my acutator is only normal or slightly tighter than normal now (loose before and dropping boost up top), so 2mm bleed would not be excessive.

ScoobyJawa

Harry,

Thanks for the input, yeah - my bleed hole is drilled out to 1.5mm but I haven't stretched the spring.....

John,

We certainly all do have a wobble now and then but enough of that, I'm talking about the Dawes
What hose are you running and where did you get it from? I no longer have a long enough length of hose from that supplied to set it up how you've got it, any ideas where I can get some from?
I followed with interest when you were talking about the acutator, do you think this will help Scott and I, and how do we do it? Also, from what you are saying it would make sense for us both to increase the bleed to 2mm, if we tighten the acutator?

Once again, thanks to everyone for the input, it is all greatly appreciated, especially since we are all pretty new to this in the UK

Cheers, Neil.

john banks

I use 3.5mm inside diameter stuff from Falkland performance. It is more rigid, but I don't think otherwise is any better except it has heat resistant woven wrap, but it tends to fray so I remove it ending up with black bose.

I wouldn't bother tightening the actuator if you are not running a raised fuel cut.

ScoobyJawa

Thanks John

So to sum up - should we increase the bleed, and leave the acutator lone, or leave it all and keep everything how we've got it now?

Cheers
Neil

john banks

Leave it all alone and enjoy, or maybe increase the bleed to 2mm (trouble is going back but I don't think you would want to). Until we sort the fuel cut lifter out and test it... if you are brave (or some would say stupid).

[Edited by john banks - 2/22/2002 11:17:18 PM]

lizzard

John

I got my Dawes and I would like to ask you or any one else out there a couple of questions.

The OAT (outside air temperature)here in Trinidad in the day is about 31-33 deg C and the average altitude is only about 100 feet above sea level. Yes we do have mountains the highest one at just over 3000 ft, however no roads to them, tropical rain forest and all.

Those figures give a Density Altitude of about 2600 feet.
This means that the car "sees" the air as though it were really at 2600ft.

With this in mind do you think that i need to drill the bleed to 1.5mm or leave it as standard.

Does the lower density air cause any less spiking?

Thanks for the replys in advance!!

john banks

I have not tried it

But theoretically you should have less spiking as the turbo will spool up slightly slower. Howvever, the main reason for a bleed is for part throttle boost control not for spiking which is a happy side effect. Even with less dense air you will find the Dawes is rather on-off on a small turbo. If you have a TD04L, go and drive at 4000 RPM in 3rd gear. If you get loads of boost on part throttle you need more bleed. The ideal response is where you have to move the throttle some way to go from 5 to 10 to 15 PSI and you can hold a chosen boost setting easily with your right foot. You cannot do this as easily with a Dawes on a TD04L with a 0.5mm bleed. Even if you like the on-off delivery, it runs too lean for my liking when you have 15 PSI on less than half throttle. I now need 3/4 throttle to get 15 PSI.

mutant_matt

And I got one for you guys.....I took the Dawes apart the other day and afterwards (put back together) noticed a brass washer that must have come out of it.......

The queston is, does the washer go under the ball baring or at the other end at the base of the spring?

Anyone?

Cheers,

Matt

john banks

Matt you numpty - you are like the guy that lost his ball. Why do men always have to take everything apart No washer fell out of mine, but it must be from the ball bearing seat?

ScoobyJawa

LOL @ John.

Can't remember either!!!

Well, we had a little play today and have reduced the amount the boost fluctuates quite a bit, this was simply by shortening the piping as much as possible. We have about 4cm of pipe to the turbo nipple and about 5cm from the dawes to the wastegate nipple. We found on both cars the needle was much steadier.
For me this meant I removed about 4/5cm out of the pipework to end up with the above figures.

We have left the bleed alone at 1.5mm. If in time we did drill it out more to 2mm would this effect the bhp/torque figures for better or worse?

I am running about 1.1bar held and scott is about 1.15, during full throttle gear changes we can get a peak of 1.3 bar for an instant then its gone. I'm assuming this will be ok?

Cheers
Neil.

john banks

I don't get the 1.3 bar peaks - possibly because of 2mm bleed, but I don't remember then when I had 0.5mm or 1.5mm bleed. 2mm would not reduce anything except the rate of spool up very slightly.

Your length of hose now sounds about the minimum which is similar to mine.

[Edited by john banks - 2/23/2002 3:14:04 PM]

ScoobyJawa

Interesting, ever since fitting the Dawes both scott and I have had peaks usually about .1 to .15 above what held boost is. Seems only to happen on full throttle gear changes and very occasionally at night - very cold weather - when you gun the throttle in 5th.....

As I said - it only does it for a fraction of a second and goes, no sign of any boost cut or fuel cut. I'm just concerned that going to 2mm, there is no way back once done - except buy another Dawes coz they don't exactly cost much
Also, another point, the spring is how it came to use, we did not stetch it at all, any chance that could be a reason?

john banks

Oh yes I remember now! I did have some spikiness before I stretched the spring I posted on it previously see the FAQ - I only held it at about 30% longer than its resting state for a few seconds and repeated it IIRC. This is enough to mean you don't have to have it screwed in a long way in and felt a bit cleaner in boost behaviour afterwards. Try this before increasing the bleed maybe? If your part throttle is smooth then don't increase the bleed.

ScoobyJawa

Horay!!!! We got a result

Yeah - part throttle is fine The dawes is screwed quite a bit down but there are still 3ish threads on the screw part still showing. As I said though, we left the spring alone so we'll give that a bash at our next "play"

Cheers again John

Scott W

Hi John,

I tried expanding the spring earlier, and deliberately left the boost pressure down so I could start to increase the pressure as I went along without continually hitting the fuel cut.

I'm still getting the odd peak of 1.3, even though I'm holding 1.1 consistently. Do you think the best method is to increase the bleed hole to 2mm?

BTW I ran the car without the Dawes on the car, my boost was peaking at 0.7 bar and holding at 0.6 with a MY00 running full Scoobysport system, and K&N Induction kit - Green AE802 I am therefore wondering if this is why so many people are complaining about the MY00's feeling so slow, as Neil's car was peaking at 1 bar, and holding 0.9?

Edited to add that the thread on 22B is very interesting, and that I'm not going to be one of those people who blows their car up!

[Edited by Scott W - 2/23/2002 11:46:05 PM]

john banks

The figures you show for peaks and the standard car are not too off the ball. I think you may benefit from 2mm - it won't be horrendous anyway. Every car seems a little different - after all taming spool up is a fairly "chaotic" almost exponential process and we are trying to stop it at a setpoint - why do you think EBCs end up so complicated - not an easy job

dowser

Scott


Peaking/holding around .7 bar means your solenoid is not working - you cannot have refitted things correctly

Richard

john banks

Sounds like restrictor is missing if 0.7 bar?

Scott W

I'm not sure, but I'll have another try tonight or during the week and see what happens. The funny or disconcerting this is, my car went in for a service like that aswell, and the mechanics took it out for a test drive and never said a word to me.

The_Gza

I had exactly the same after trying t-uk's Dawes on my car at Crail.

The pipe with the restrictor and the pipe without got refitted in reversed places, giving me only 0.65 bar boost all the way home!

Popped the bonnet and reversed the pipes and all was fine. For reference, the pipe with the 90 bend and restrictor should be on the right hand side of the t-piece (looking at it from the front of the car) and the longer straighter pipe without the restrictor should be on the left hand side of the t-piece.

Hope this helps!

john banks

Yes the position of the restrictor is important for some odd reason!

ScoobyJawa

It was fine as Scott borrowed my old pipework for the day and I showed him how it should go, therefore the restrictor was in the right place. I used the same piping on Sat for a trip to the dealer and I was getting 0.9-1.0 bar held.............

strange...............