BIG THUMBS UP -
to the boys at AWD again for fitting my Dawes and boost gauge, what a big difference it makes, no drilling of the hole on it. It now sits at 16.5psi, lots of chattering and a big smile on my face.

Thanks again Dave, Scott and Grant & must also remember the new helper.

Paul ;D

ps Everyone should have a Dawes

 

Paul,

Good 2 hear it worked on u r mota bud
Tell u wot though u r closer No quite true, I fitted 1 in my mota and it didn`t work Ended up taking it out again, sayin that it was worth a try suppose. Just have to stick to my link

Pete

 

OK then Pete, everyone in a bugeyed, don't know about the STi's though.

Cheers buddy

Paul

 

Certainly, from being out in VKL 123's car yesterday after the Dawes had been fitted it's now got me very interested in getting one fitted

Unfortunately I can't give any comparsions as my car is a '98 and VKL's a '01 and hence a bit different.

 

Miles I hope you got your car sorted yesterday and a safe drive home.

It was nice to meet you and Ken, see you at Knockhill.

Paul

 

Find a long hill (or even not a hill it still does it) in 5th gear at 4000RPM with a 0.5mm bleed hole and then only use enough throttle to get 15 PSI. On my car this reads under 5% CO. Mash the throttle and it goes to 9% CO. This much boost against a fairly closed throttle is not good for the turbo, and certainly not good for in-cylinder temperatures and knock control. The car is simply not mapped to fuel for 15 PSI at 1/3 throttle MAF reading or not. It is not safe.

When it is flashing about it means it is under closed loop lambda control. Once it gets to significant boost or revs it goes open loop.

I can drill your Dawes to 1.5mm at Knockhill next w/e if you want. We/you have to set the boost again afterwards. Meantime you should be OK for a week if you turn it down and try not to drive so that you get a lot of boost at part throttle. Ideally you should not make 15PSI until over 2/3 throttle - huge difference.

Please have a read of the high EGT threads at part throttle in the Dawes FAQ - yes it is a US MY01, but they show really high EGTs. I bet the UK ones would as well with 0.5mm hole old or new shape.

You also stand the risk of the turbo hitting the surge line making high boost at part throttle - to make 15 PSI at half throttle the turbo outlet will be MUCH higher because of the resistance involved.

One benefit to an EBC is that you can be gentle with the part throttle duty cycles and very aggressive with the full throttle ones = best of both worlds. With an MBC on a small turbo there is a compromise.

 

Thanks John,
Pardon my lack of knowledge but how do you turn down the boost?
I am handless.

paul

John, where are you based, as I could come out to you during the week, so you don't miss any tracktime.
(I don't go out on the track)

[Edited by VKL723 - 3/10/2002 7:32:57 PM]

[Edited by VKL723 - 3/10/2002 7:35:42 PM]

 

You unscrew the Dawes. I am not going on the track at K/hill this time. Happy to do it then or visit me before - Fife. jcsbanks@btinternet.com

 

John

Are you sure that 5% CO is too low ? I've been doing a bit experimenting lately and have found more power by going even weaker than this. (don't try this at home)

As you know, I monitor EGT, Charge t, Exhaust B/P and Knock

The best advice I've had lately regarding tuning a Subaru was not to right anything off until you have tried and tested it yourself.

I know you are trying to help people avoid the pitfalls but perhaps
a more solid factual foundation needs to be built ?

Who says 5% is too low ? Where's the proof ? My car for one is only showing increasing EGT's below 3.5% CO (810mv) and it's now running 23 psi

Andy

 

John

Now you have seen inside a Knocklink, do you think you can rig up an output trigger for my water injection ?

nutter ?

 

The outputs of the LM3914N are open collector. Are you driving a relay? How do you set the duration or do you just want it to fire when the LED is lit? Can be done.

 

I need an output to pull in a relay. The relay will be configured to latch until boost drops below a value dictated by a pressure switch. Can the K/Link provide this or would I need an additional transistor chip......or something ?
My K/link, on max sensitivity is very quiet until a good thrash heat soaks the intake system and the charge T exceeds 45 C (small I/C) , at which point things start to degrade from 1st green to BIG red in about 3 seconds. Pushing my W/I button at the first amber instantly drops the signal back to first green and drops the charge T by approx 20 C.
Running the W/I on a pressure switch only loses power, I've tested and recorded result. I'm not sure that a temp probe/switch would be fast acting enough ? Hence the request for Knock control
I'd also like a buzzer on big red as it is possible to miss it on a sunny day, which ironically, is when it's most likely to light up !

 

John / Andy

Hey guys now were talkin turkey
Interfacing hmmmm a favourite past time of mine

Pete

 

Miles,

I have a 98 with Dawes, and can compare it to Paul VKL's, cause he couldn'y keep up yesteday

I fitted myself though with the aid of a boost and AFR meter, so am looking forward to getting it on the select monitor at AWD for fine tunning.

Scoty

 

Thanks JB, will discuss with you at Knockhill.

 

Andy, a few more thoughts....



Suggests peak power at 12.6:1. Is this due to the combustion properties of petrol? Or does it vary with engines? This would suggest 850mV or 5.5% CO approx for peak power assuming you can control the temperatures and detonation. So I would be worried being on the wrong side of this at high boost part throttle. It seems on Scoobies richer is often used for cooling, but makes less power. It this why you can run 3.5% CO safely with water injection? Would you get more power stopping at 5.5% CO or are you convinced you get more at 3.5% CO? Presumably you are well off the end of the fuelling map of your ECU if it is letting it get this lean?

mV %CO AFR

<600 <1% >15:1
720 1% 14:1
760 2%
800 3%
840 5% 13:1
860 6% 12:1
880 >8% 11:1

 

As the MY95 fuel cut is around 17psi I guess I'm well off the map at 23 PSI However the clever ECU continues to extrapolate and increases the injector duty proportional to air flow from the MAF up to 100% IDC then you are on your own.
Now everyone goes "Ooooooh 100% duty = bad things" Oh Yes ? have many experienced these "bad things" ? I suspect not.

Myth 1 - 'Injectors stick open' Now why would they do that ? It's just a solenoid valve.

Myth 2 - 'The coils overheat' No they don't. I've had one powered up for 30 minutes and it was only luke warm and that was without any cool fuel passing through it. I would suggest that an inductive load being pulsed would draw more current due to the initial inrush current required to establish the magnetic flux to create the inductive load.

Myth 3 "Injectors do funny things above 85% IDC" Well yes, at high RPM they go 80,81,82,83,84,85,86,100% (approx) The reason is simple, at 6500 rpm the 'off' time at 85% is approaching 2ms, this is too short a period to allow the injector to close and reopen.(helps explain myth 1) There will therefore be a step change in fueling at this level.

I target 100% IDC at max boost and adjust the fuel pressure to trim mixture. I don't target a specific CO% as the optimum setting can vary depending on the fuel composition (and additives )

I tune for maximum acceleration 'G' force, which I data log. I also monitor charge temp, EGT, boost pressure and exhaust back pressure. ( sometimes I even watch the road )

My water injection is only compensating for the fact I have no control over ignition advance which has been mapped for 100 Octane at 0.8 bar !

Who needs a link

Andy

 

Some very interesting points Andy, thanks.

What do you think about the wastegate solenoid maximum duty cycle? (I know you don't use it now!) I have stuck to 95% for fear of overheating it.

I have a circuit for a fuel controller which will boost or cut the MAF voltage depending on RPM - at present it is just two levels - above and below a variable RPM value. This may also have an effect on ignition timing. I will not be trying it until I have a Knock display though.

If you are running 100% IDC then you have other ways of controlling fuelling I see you like to go mechanical where possible since you have now taken over control of WOT fuelling and boost from your ECU as well as fuel cut You do qualify as a nutter in the politest sense. Max respect for working these things out and challenging the assumptions. Many would give up with the hardware you are working with long ago and move onto bigger injectors and remaps. I'm sure you'll continue to (hopefully safely) outdrag them all

 

John

I think you already know my view on the boost control solenoid duty........Test it yourself ! Don't write it off due to what others have said re overheating. If you connect it for a period and it doesn't fail, then it's sure to be ok in use as it will have air passing through the core to stabilise temps. If it blows then there are plenty around just swap someone a resistor for one !
You can experiment with mine if you wish but it's only a 2 port, don't know if it's the same coil ?

Andy

ps How does 0 - 100 in 9.9 sound and that's real mph, not speedo. Speedo 0 - 100 is under 9 secs

 

That is TVR Tuscan performance m8.

 

I don't think running without a bleed hole of 1.5mm or more is safe, but if they checked that your fuelling was good on PART THROTTLE at full boost and it is then fine - it is VERY unlikely to be fine. Mine was too lean. I don't know if you still have an uppipe cat. Or possibly when you ordered it had a 1.5mm hole already? Standard they are 0.5mm.

No disrespect to AWD, but these things generally tend to be setup at wide open throttle without consideration of the part throttle issues, and they are very real issues.

If you are happy with it then fine, but if you are at K/hill next w/e I can have a look at it for you, and possibly also discuss with AWD their setup method.

Bascically on a MY00 with no extra bleed you can be at 15 PSI on 1/3 throttle and be at under 5% CO. This is almost dangerously lean. The standard car runs up to 8-10% CO at this boost at wide open throttle and is much safer for in-cylinder temps and reducing the chance of knock.

If you run this on the track I would not want to see your engine go.

Maybe I am a drama queen, but you can be at full boost and the last half of throttle travel controls the mixture richness. This is clearly not the ideal function of the loud pedal

[Edited by john banks - 3/10/2002 11:37:42 AM]

 

Thanks John, you have me worried now!
Should I run with it or change it to 1.5mm. I don't want any problems. To me the hole looked like a 0.5mm. If drive it without full boost, just with the boost at a very low, about 5psi would that be safe, drive carefully it should be ok.
I must buy a 1.5mm drill now.

Thanks again

Paul

EDIT. I run with a Scoobysport Downpipe and Superunleaded.

[Edited by VKL723 - 3/10/2002 6:24:11 PM]

 

john,

I have been wondering how you came to the conclusion that they go lean on part throttle?

I find,with the lambdalink,that in top gear it is easier to watch during spool as it goes up slower.just before peak boost is reached,my last light comes on and holds until lift off.at mid boost my lamdba is flashig like mad between no light and 3/5%,then at 3/4 boost the leds start holding and climbing.I feel that the afm is pretty pointless below about 2600rpm.possibly the select monitor is far more accurate than our meters throughout the rev range.

please explain this as I am the first to admit that I do not have the best understanding of electronics.I much prefer being up to the armpits in oil than wire a 13amp plug.



[Edited by T-uk - 3/10/2002 6:57:25 PM]

 

Yeah but you are a nutter and that doesn't count

Hear what you are saying, and anything to take apart crap presumptions is nice. However, it does seem worrying that the AFR goes up by 4% (CO) with little change in boost by moving the throttle? Obviously not what the mappers intended.

I am not going to try running any leaner than 7% CO at WOT given that Possum Bourne recommend this, the Link tuners with considerable experience do this, and some tuners aim for 9% CO for safety.

However, I have just done what I slagged someone else off for in antoher thread - quote an authority. Shoot me down

[Edited by john banks - 3/10/2002 10:56:33 PM]

 

Andy,

There are some really fast acting n/o temp switches available from RS bud. I`d imagine with the right selection a temp based system should be able to react as fast as a system based around knock detection As a knock based system would continually be switching on and off for short periods, where as a temp dependat one could hold for longer in the event that a latch was fitted.
Saying that the temp point where knock happens would need to be consuistent.

BTW Andy u r puttin no buzzers on my mota

Jus my 2p worth guys
Pete



[Edited by teknopete - 3/11/2002 1:21:13 AM]

 

LOL at buzzin Pete

Prob with temp control is 1 - Getting the probe/sensor in the air flow. Then 2 - As air has such a low specific heat capacity, it can take too long for a metal sensor to reach media temp.

I suppose I could just set the trigger point lower to compensate for the delay ? I currently use a 1 mm bare wire thermocouple. The sensing head is about the size of a grain of sugar !
The charge temp can rise 20 deg C in a matter of 2 - 3 seconds.

I'll check the RS cat tomorrow at work....er I mean today

Need to save up for a FMIC wot you been buying lately Pete ??????????




[Edited by Cosie Convert - 3/11/2002 1:41:25 AM]

 

I can convert the LM3914N outputs to something able to drive relays (you would use something like a TIP122 or TIP127 darlington transistor with one or two resistors and a protective diode on a small board like I use to drive the boost control solenoid) - the simplest way is to get them to switch for just as long as the Knocklink LED is lit. I take it the relay latch you already have working?

If you want proper logic control with complex conditions for a few sensors, you are better going for a uC solution, but it is no small job then.

[Edited by john banks - 3/11/2002 8:25:47 AM]