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Just changed MY00 802 for 801......

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Old Feb 6, 2004 | 11:48 AM
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From: Deepest Darkest Dorset!!
Talking Just changed MY00 802 for 801......

And the car seems a lot smoother, seems to idle better, and might even be a bit more responsive, time will tell, but for know I'm happy!

Ron.
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Old Feb 6, 2004 | 01:23 PM
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Wink Do Subaru know something we don't....?

It always bugs me - why would they have designed a new ECU especially for one single model year (2000) if it was going to be all round worse than the previous one. We know it fuels a bit richer so is a bit safer for modding but I doubt thats why they would have done it! So what else? I also wonder wether there is a slight touch of the Emperors new clothes over the 801-802 replacements. I suspect in some cases just replacing an 802 with another 802 may make the car feel different due to the resetting process etc.
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Old Feb 6, 2004 | 01:59 PM
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I'm always resetting mine, so that wouldn't have made any diference, I've got an AFR so can keep an eye on the mixture, also got a dawes, so will reserve judgement on that side, i might even remove the dawes and see what it's like with the original boost control, we'll see.
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Old Feb 6, 2004 | 02:15 PM
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I think they did it because of all the problems with the MAF, although they didnt realise it was the MAF causing running lean blow ups at the time. Therefore, they went for a more conservative map. I read that somewhere, and if its the case, they are bell ends

MB

Last edited by Dark Blue Mark; Feb 6, 2004 at 02:16 PM.
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Old Feb 6, 2004 | 04:28 PM
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Also tighter emissions control was a factor on the map of 2000
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Old Feb 6, 2004 | 04:44 PM
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I'm not surprised it feels more responsive... look at this dyno plot.

If you read further down, and look at the various map comparisons, you'll notice the fuelling is the same up to 4000rpm, but after that is much richer for the AE802, which would explain why the max power is 202bhp, compared to 217bhp for the earlier models. However, although the max power is reduced, cylinder cooling is increased and the knock point is further away, allowing "safer" future modifications.

The low octane ignition map is also alot safer on the later models, as the timing is more retarded at higher loads/rpms. Although, if you are using Optimax/BP Ultimate, this isn't as applicable as to those who are using standard 95RON unleaded.

The boost maps are very different. The earlier models have a static map, with maximum boost aimed for regardless of load, whereas the AE802 map is much more defined. For a given rpm, the higher the load, the higher the boost. This would cause the later models to have a much more progressive and smooth acceleration, whereas the earlier would have more of a kick.

The duty cycle maps are also very different. The earlier map has a higher duty cycle at lower loads, which you would expect as it is aiming for maximum boost immediately. The later map has a dynamic duty cycle from 3800rpm onwards, starting off with a lower duty cycle that gets progressively higher as load (and boost) increases.

The rpm increments for boost/duty cycle maps are very different as well, making comparisons more difficult.

That's my interpretation of all that lot anyway! I'm sure if I've misinterpreted anything there, I will be corrected shortly...
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Old Feb 6, 2004 | 07:21 PM
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Default Nice post Judge!

Understood most of it but what is a duty cycle and what are the implications of it.

In mickey mouse language I think you are saying the following...

1. MY00 is smoother so may not feel as fast.

2. Not quite so much at high rev's if you are thrashing it.

3. But if you are thrashing it it is a bit safer, especially if you start sticking go faster bits on.

4. Less likely to harm MY00 if you are sticking crap petrol in.

Last edited by Scoobydick; Feb 6, 2004 at 07:22 PM.
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Old Feb 7, 2004 | 12:09 AM
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Right, having digested all that, I've got a full decat on my car, and have now done a few miles, it definately is smoother, and feels more urgent, although I'm still running the dawes, so the boost control is left to that, but the Dawes afr still shows a blue light on anything over half throttle, so still rich enough, it seems a bit more acurate now though, as i've noticed the ocasional blue/green light showing.
I only ever use regular unleaded, and have tried optimax for a few tanks on the 802, and it didn't like it at all, I even reset the ecu and still it didn't like it, so I stick to regualr! could this be harmful, or am I just not getting the best out of it??

Ron.
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Old Feb 7, 2004 | 01:20 AM
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Understood most of it but what is a duty cycle and what are the implications of it.
In this case, Judge is talking about the boost solenoid duty cycle. In simple terms, this means the percentage of time the boost solenoid is "on" and "off". When the boost solenoid is "on", the turbo bleed air is vented into the inlet manifold, allowing the wastegate to remain shut. When the solenoid is switched off, the bleed air will be able to act on the wastegate actuator, opening it up.

1. MY00 is smoother so may not feel as fast.
Not only does it not feel as fast, it's not as fast, period. You're on the money with points 2, 3 and 4 though.

Ron, do you run an AFR meter? It'd be interesting to see what readings the car produced on the 802 with Opti and regular unleaded. Strange that you say the car just didn't like it, what exactly did it do/not do?
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Old Feb 7, 2004 | 10:18 AM
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GM,
I do have the dawes afr, but I never ran the car with 802 and optimax since fitting the afr, so can't comment on the readings, but where I always had a blue light on the 802, I now get a blue/hint of green light, so running slightly weaker, but still safe.
With the 802 and optimax, even having reset the ecu the engine was all over the place, not smooth, and generally just not as nice to drive as on regular, so I stopped using opti and have used regular since, I guess I could try opti again with the 801, maybe.
D'you think it'd be worth putting the old boost pipes back on, and seeing what it's like without the dawes on the 801???
Obviously with the dawes I'm not giving the ecu the chance to control the boost, so I maybe haen't had the full effect of the change really, I might do it just to see what it's like.

Cheers for comments.

Ron.

As a footnote to all this, I had a K&N ind kit, but didn't get on with the extra sound, so removed it, I then had to adjust the dawes cos I wasn't getting as much boost with standard airbox.
What do you make of that??
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Old Feb 7, 2004 | 11:48 AM
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Lower pressure drop with K&N vs airbox. The greater proportion of atmospheric pressure that your turbo can compress the better for power as it keeps spool up better, charge temperatures lower and reduces exhaust gas back pressure.
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Old Feb 8, 2004 | 10:31 PM
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Stop fiddling Ron

MB
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Old Feb 8, 2004 | 10:54 PM
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From: Deepest Darkest Dorset!!
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Mark,
Now I've got this I'm done I swear, I removed the dawes yesterday and went for a 'warm' drive, it's like a totally different car, MUCH quicker, and just smoother all round, plus the fact I don't have to tell the ins co about the dawes now either!!
Made the driving experience like night and day!!

Ron.
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Old Feb 9, 2004 | 12:22 AM
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'Now that I've got this I'm done I swear'

That'll mean a PPP/Tek2 next then...lol
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Old Feb 9, 2004 | 09:06 AM
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With the 802 and optimax, even having reset the ecu the engine was all over the place, not smooth, and generally just not as nice to drive as on regular.
Is your MAF OK? Did the engine improve as you used up the Optimax, so that by the time you put normal UL back in, it felt OK again? Try resetting the ECU whilst using normal UL...
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Old Feb 9, 2004 | 01:43 PM
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Question Anyone know Where I can you get an 801 or PPP from

As above plus is just a straight swap? Car is MY00 Turbo 2000 with full decat

Thanks

Simon
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Old Feb 9, 2004 | 04:42 PM
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For Sale section...? Possibly a breakers yard...?

Yup, it's a straight swap. The wiring loom should simply unplug from your existing AE802, and plug into the AE801 or PPP.
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Old Feb 9, 2004 | 11:08 PM
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From: Deepest Darkest Dorset!!
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simply lift the carpet in the passengers footwell, undo four bolts holding the cover plate on, another two that hold the ecu in, and literally unplug one and plug the other in, then do the above in reverse!

I tried the optimax at least a year ago, and have never had a MAF code show up, however as I recent;y fitted an induction kit I put a new maf on anyway just to be safe! Although I have since removed the ind kit cos I didn't like the increased noise levels.

So If I need fuel and I'm passing a Shell garage I may well stick a tankfull of Opti in and see how it goes.
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Old Feb 9, 2004 | 11:23 PM
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From: Bournemouth - 5x Ex Impreza owner. 997 GT3 CS.
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Ron - you are very unlikely to get a MAF fault on CEL. Even when its very dead.

Bout time you got a knock link too

MB
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Old Feb 10, 2004 | 12:44 AM
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From: Saaf Oxhey
Talking My pennies worth.....not very technical but........

......got an 802 on MY00, running a K&N panel filter, full decat and my car hated Optimax, ran lumpy, idled terribly and no real pick up, and that was after an ecu reset. Only thing it ever liked was ESSO SUL, ran like a dream.
Then came BP Ultimate, knock greatly reduced, smoother idle and a marked improvement in throttle response.....been messing recently and now run a 50/50 mix of Optimax and Ultimate.....................car is amazing, loads of throttle response, smooth as **** on idle, and, as an added extra it pops and bangs like a good 'un
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Old Feb 10, 2004 | 08:54 AM
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A 50/50 mix of Ultimate and Optimax? That must be a pain in the **** to achieve!

Ron, have you tried BP Ultimate? Must admit, mine also runs better on it than Optimax. Not a huge difference, but I do get my Nectar points as well...
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