Tuning an auto 9-3; how high dare I go?

[AdvancedRoadcraft]

Have just sold my beloved 9-3 (back to the chap I bought it from 5 1/2 years ago, would you believe!) because neuropathy in the left foot means that I should no longer really be trying to control a manual.

It was running at about 275 bhp so that's what I'm used to the feel of, have got used to and enjoy using.

So...my question is if I buy an auto 9-3 (I just love them) as a replacement, how far dare I go without compromising reliability/longevity too much?

Real life experiences particularly welcome - but 'hypotheticals' from experts also useful!

thanks in advance, B

[sgould]

The 9-3 hatchback up to 2002 has the 4 speed auto box.  It is much less strong than the manual.  In the early 9-5 with the same gearbox the Aero manual was 230 hp and the auto was 200 hp.  It was due to limiting torque.  The actual performance was not so difference.....

[Audax]

The 9-3 hatchback up to 2002 has the 4 speed auto box.  It is much less strong than the manual.  In the early 9-5 with the same gearbox the Aero manual was 230 hp and the auto was 200 hp.  It was due to limiting torque.  The actual performance was not so difference.....

No, to both.  The gearbox between the 9-3 and 9-5 were similar families but actually different, the 9-3 even had a B205R engine options that went to 205hp with the auto box, the 9-5 Aero's were both 230hp for manual and auto boxes and to be fair, I doubt that the autobox was weaker given how many failed 9-5 and 9-3 manual boxes I've seen vs. auto (for the earlier cars certainly) I'd suggest that the manual was the weaker option. For the 9000 they limited the Aero auto to 200hp and the manual had 225hp but that was a totally different box again.

Anyhow, I'd suggest that you could go to 275hp with an autobox as long as you don't abuse it, but then it won't be hp that kills the box it'd be torque.

[sgould]

Well there's certainly a difference in the engine outputs between the manual and the auto.

[sgould]

And in the 9-5 there's the same difference for the Aero.  And the workshop manual has a slightly different lower value for the max torque in the auto.

[Audax]

Yes, max torque is lower but the bhp is the same

Anyhow, I ran a 9000 autobox with the car pushing 240hp and over 330 nm of torque and the gearbox didn't explode.  To be honest, even with a standard map and poor driving you could kill the manual more easily than the auto (but with a tuned car and doing boy racer style pulling away you will kill the autobox) but to suggest the autoboxes are weak isn't something I believe as I've seen many a highly tuned 9-5 Aero with an autobox that hadn't failed and many more manuals which had. One guy when tuning 9000's asked for a map that removed all the torque limiters and took his car to over 400nm of torque, he destroyed manual gear boxes after a single nights stock car racing....

[sgould]

My auto 9-5 Aero is still OK with 300 hp after 85,000 miles with the upgrade. Now at 104,000 miles.

Previous 2002 9-5 Aero was also auto, but 280 hp.  Gearbox went clunky at 103,000 miles after 30,000 miles of Hirsch tuning. New owner replaced it at 130,000 miles.

But I'm trying to find out if the rumours of an upgraded exchange auto box that will take a lot more than 400Nm are true.   I was told that if I need an exchange box, these can be had for £2k.  But the info was at least second hand.

[phoenix]

Personally I'd be more worried about the plasticine chassis coping with extra torque than the gearbox

The 4 speed AW boxes share the same basic mechanicals for the 9-3 and 9-5 but have different gear ratios and control software, both of which will impact on the durability.

If you want to tune the 9-3 then there are without doubt IMO two elements: the chassis and the power output. I've driven a manual 9-3 Sport on stock chassis tuned to ~275hp and it was not very pleasant. The front end squirmed all over the place under acceleration.

In terms of enjoying the car, I'd go for a Viggen rescue kit before any power upgrades. We currently have a 185hp manual 9-3 on stock chassis but with Abbott steering rack clamp. It makes a huge difference (it's t'other half's daily driver and I didn't tell her I'd fitted it, but straight afterwards she asked me what had I done to the car because it felt much better).

To get the most out of a power upgrade with an auto box, I'd be looking to go for a 3" downpipe and higher flow intercooler, plus an Aero Cobra pipe.  On my 9-5 I had the cobra pipe then added firstly the exhaust then the intercooler, without making any software mods. Both of them had a similar effect- reduced spool and opened up the top end, so more of the rev range can be effectively used.

Making sure the ATF is changed often will also help protect it.

[Audax]

If you want to tune the 9-3 then there are without doubt IMO two elements: the chassis and the power output. I've driven a manual 9-3 Sport on stock chassis tuned to ~275hp and it was not very pleasant. The front end squirmed all over the place under acceleration.

I would totally agree with that, If I had to chose between a standard Viggen or an Aero then I'd go for the Aero. The Viggen is just too much with the standard chassis setup, once you add a rescue kit it's actually becomes driveable.

[AdvancedRoadcraft]

Thanks to all who have responded so far; more thoughts would be welcomed.

Don't worry - suspension/handling/braking would all receive attention (both refresh and improve) before going forward with power increases; that's the way my current 9-3 Manual was approached and I'd go down a similar route with the proposed Auto.  I'm fairly well versed in how to improve the handling and how to get the increased power; was just unsure how much the auto box could take.

Seems, though, that the auto box (at least if not abused) could take the sort of power and torque that would keep me happy.  I'm not a "Traffic Light Grand Prix" kinda guy - but I do like my mid-range brisk overtakes!  (Saabnoob's point about using the gear shift rather than the kick-down was a good thought in particular.)

Thanks again, chaps.

[win_k]

The AW 50-40LE auto trans has been successfully used at 300 BHP, the killer is sudden surges is torque.

So, I'd suggest a custom tune, preferably with a fairly local source that can road tune the engine and really provide a very smooth torque curve.

Most of the off the shelf tunes available are perfectly suitable for the manual transmission but the T7 system is not as aggressive in limiting torque as the T5 system and care needs to be taken to keep the box health.

[AdvancedRoadcraft]

Thanks for the input, chaps.  I've (rather reluctantly) decided that as an auto replacement for 'my' 9-3 (in whatever configuration) would be too emotional a direct comparison, I'm going to go down a totally different route.  I've bought a Range Rover.

Thanks for the help over the years; it's been much appreciated.

Best, B

[sgould]

Good Luck!

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