kevin stanton

I've got a MY99 turbo, and was wondering if there was a easy way of turning the boost up a notch or two.

I've never owned a turbo car before, so this turbo thing is all new to me.

I've got a rolling raod day coming up in Feb, basically i'm after an easy way of getting a bit more power for the day.

Its got a Scoobymania back box and K&N element.

Any reply would be appricated. (i think i'm safe saying that, after all its not the muppet forum)

Cheers
Kevin

SecretAgentMan

Look at the threads concerning that "Dawes" thingy...basically it's a fancy bleed valve.
In theory you bleed off the boost that goes to the solenoid, so the system "sees" lesser boost than it's actually producing.

As long as you use that Dawes device (looks as if it's not producing any nasty boost spikes like other devices), and stay below boost fuel cut (~17.summat psi's IIRC on latter versions of the scoob) you should be safe.

AS always...it's your car...and be prepared to pay if it breaks.



/J

T-uk

the Dawes is a ball and spring mechanical boost controller that does not remove fuel cut.I also think the ECU knows you have upped the boost slightly as some people are finding the cars fuelling the same as before,so not leaning out like a superchip type boost upgrade.

we fitted one to a m8's standard MY00 a couple of weeks ago and then took it to a r/r day.he got 241/flywheel,136@wheels,244/torque not bad considering a fully decatted MY00 got 213,117,206 .my own fully decatted MY00 car on this r/r got 234,139,227(different day).

the owner of this car,has also found it transformed on road since fitting the Dawes,he always felt it gutless to earlier scoobs he has owned(about 8 now)

john banks

Most Superchips cars are very rich - the ECU responds to high boost by chucking fuel in and retarding the ignition.

I think Jerry was not referring to the MAP sensor being fiddled with but extra boost being bled away from the wastegate system.

T-uk

sorry ,I thought that superchips raised the boost and did not let the ECU know it had been raised,so it would still fuel for the standard boost leaning it out slightly.

john banks

The ECU is fooled about the boost yes.

The fuelling is almost entirely based on the MAF not the MAP sensor. So the ECU knows there is a lot of boost even if it gets a low MAP reading, and so chucks in fuel. Similar for ignition retard. So you end up overfuelling which reduces power but keeps cylinder temperatures cooler. The ignition retards perhaps excessively which reduces the chances of det, but can also RAISE the cylinder temperatures. So you end up with an inefficient mess if you go too far beyond the ECUs intended operating zone.

Sam's Evo has a fuel cut but no MAP sensor. It uses the MAF and when too much air goes in it stops the music.

[Edited by john banks - 1/26/2002 7:44:56 PM]

EvilBevel

John, small point ...

>>The ignition retards perhaps excessively

It will actually "advance" when seeing lower boost than really present (on MY99/00). Read advance as "retard less". But you are absolutely right about the MAF.

We should really stop this game ... your car fuels based on MAF voltage, MAP signal has got very little to do with fueling (talking standard ECU here). It does have an influence on ignition advance/retard.

This must still be the longest living myth on Scoobynet.

Oh, and John, the overfuelling is quite bad on the MY01, on a MY99/00 it works pretty well actually. At 1.2 bar, you'd see something like 10 % CO, too rich yeah, but safe, and not power sogging.*

The ONLY reason to stay away from superchips is because they alledgedly remove the fuel cut altogether.

Now hold on ...

I never actually heard definite proof that the Superchips setup does remove the fuelcut.

Can anyone state so with 100 % certainty ?

Theo

* as always, check on your own car, don't go blind on information like this

john banks

"Originally I had assumed that boost pressure (i.e. output from the MAP sensor) was used by the ECU as a major input to the ignition map. On further investigation, it appears to have a minimal effect. I would guess that the MAF sensor plays a more significant part (along with RPM etc)."

http://www.force8.demon.co.uk/impreza/bcontrol.htm

So not a myth according to those that have measured it?

I know personally of two Superchips owners who have seen 25 PSI with no fuel cut - one intentionally, the other when a hose came off.

Also I have read the installation manual for Superchips that Falkland performance showed me when they were trying to tell me that my newly purchased MY00 PPP was the same!

The Superchip is an adjustable voltage CLAMP.

[Edited by john banks - 1/26/2002 8:03:44 PM]

EvilBevel

Joh, explained badly, trying again

"Myth" was related to "cars running lean when you up the boost". They don't. MAF is the answer - as you said.

As for ignition, yup, MAP not a major role at all, but a role nonetheless.

So you are pretty sure the Superchip does away with the fuel cut Damn, maybe someone should send'm a £5 circuit... incredible.

john banks

You do wonder about the role of MAP in timing when the 01 PPP runs 1.2 bar and the ECU thinks 0.7 bar But I forgot 01 ECUs are SO CLEVER they run on the edge all the time. Almost as cool as a surf dude. I'll dig out a few circuits

john banks

http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm

The Superchip is similar to this.

http://www.mr2.com/ARTICLE/FCD.html

This is what the Superchip should've been. Don't be scared it is only a few wires and gates.

The second circuit merely LIFTS the fuel cut. I would put this on my car if I did not have a 19-20PSI fuel cut on the PPP ECU.

Would probably be better done now with a microcontroller.

If it means nothing to you don't worry, but if you know any electronics at all it is laughably simple.

JKJ2

T-uk

Are the figures you are quoting at the wheels real numbers, I would have thought that the Scooby was putting out more than that, and if not, where is it all going, surely you can't lose all that through the transmition/drivetrain. My old 1700 X-flow in Supersprint tune in my Caterham is meant to put out 135bhp at the flywheel and is actually putting to the wheels, 112bhp. Tell me PPP Impreza's are putting out more than 140bhp, they certainly feel like.

Cosie Convert

Most of the scoobys at a recent RR test had recorded 'losses' of around 100 bhp. ie 140 paw = 240 at flywheel (corrected)
Part of the loss is transmission and part is the 'DIN' calculation that takes account of the ambient conditions in the test cell (power robbing heat)
I must admit I was also surprised by how low the standard Impreza's paw was.
I had a 2.0 pinto in a mk1 Escort that put out 145 at the wheels 180 at flywheel, but then again, it did feel faster than a standard UK Scoob !

SecretAgentMan

So Superchipped cars runs very rich - really weird, because I know for a fact one of our fellas shot a piston due to detting, and running way too hot, IIRC there was a few valves that had been burnt as well - and that does NOT sound like rich running to me.

Again I could be talking pure bollox.

AFAIK SUperchips fools the ECU to see a lower MAP, and up's boost with a bleedvalve...the said mate ran 20 psi's held....

Anyway, I'll get me coat...

/J

john banks

The ones I have seen plots of all run rich, sometimes in double figures %CO. But obviously there comes a point.... where you take it too far?

EvilBevel

Jerry, we are talking different things here ... the "fooling" word is bollox, a lot of tuning devices do exactly that. You could say that even with a Unichip, you are "fooling" the standard ECU. (And if you put on a Link etc, you "fool" the car as well, as you took out it's original brain )

Now of course, if you go too far, like many of the Superchips guys, your car will be detting anyway, because your turbo turns into a hairdryer in distress.

Don't get me wrong, I'm all for doing the proper job, but it doesn't help people if they are fed the same line over and over again.

You would need to boost the TD04L on a MY99 to about 1.5 bar before you would get any fuelling problems. But your engine would melt anyway because of the ridiculous charge temps.

Theo

EvilBevel

And I should correct myself in that it's not so much the midrange boost, but the held boost above 6000 RPM that would get you into fuel trouble.

We thought we found the limits of the standard ECU / MAF setup with running a VF23 at 1.1 bar at 6.500 RPM (limit of IDC) ... but with an uprated fuel pump, we are seeing something like 75 % IDC ...

As always, I'm talking MY99, and a target CO of 9%

SecretAgentMan

The midrange boost vs fuelling is correct Theo, I've seen the same thing on the Link...it's kinda logical...there are a few more explosions at 6500 rpm, than at 4000.

I'm seeing ~60% inj duty at 400 rpm on my VF24:ed, linked (brain transplant? ) MY00 - @ an AFR of 12:1 (CO 7%)...and 93% at 6500...

Have you run your 23 on the stock ECU? Any fuelling readings?

/J

EvilBevel

We did when we started mapping the Unichip ... basically, you start with a zero map, and work from there. Zero map = car 100 % controlled by standard ECU.

At 1 bar held boost, CO was something like 7-8 % at 6500, too lean for our taste (some will disagree and only think you are wasting fuel targeting for 9 %). Engine could survive then on the road, but wouldn't feel safe on track.

So we had to take away some fuelling at midrange (read take away as: what the standard ECU would normally do), and up considerably above 5500 RPM to get to 1.3 bar midrange / 1.1 bar at 6500 with 9 % CO.

Mind you, all this changed with an uprated fuel pump, and now the whole map will be *negative* (lean out compared to what the standard ECU would do following the MAF readings).

So I think it's not a good idea to fit a VF23 to a standard ECU car, if only because the spool up wasn't really good, so we did want to be able to control boost, mixture and ignition.

Warning: don't try to compare this to older cars ... the MAF is - although a bit less fragile) not equipped to correctly read the airflow and maxes out pretty soon. On a MY98 I would either keep it sensible boost wise, or fit a complete MAP based replacement ECU if you want to fit bigger turbos.

Warning 2 : I still have the original filter housing with a standard panel filter... another car may show different readings when they have cone filters etc... so it's still a case of judging car by car basis, just to be safe. But *potentially* a MY99 can keep up quite nicely in the fuelling department.