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Discussion Starter #1
Hey guys, I've been idly thinking about adding a water injection system to my 99 9-3 2.0T to help it cope with the 19-21 psi of boost that my turbo can now put out thanks to the wonderful folks at Speedparts. How many of you have done it? Is the Aquamist system reliable and effective? I've seen ERP's page on his custom system, and while I could save some money building my own from separate components, I'd probably just go with an install-ready kit.

Also, assuming I do decide to go with water injection at some point, should I upgrade the IC to a Viggen-spec first? I'd think I probably should..... Thanks for any advice!
 

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Pyro,

I won't bother going in to all the basic benefits of water injection, 'cos they're adequately covered on the Aquamist site. It's popularity on earlier cars was, I believe, born out of the inability to accurately control fuelling, boost and ignition timing within a single closed loop system. Trionic gives you that and, in most applications, you won't notice a huge effect from water injection, apart from the benefit of a further cooled charge.

Where I believe it does show it's real value is when you're pushing the power outputs very high. With higher power outputs go two things- more boost and increased combustion/EGT's, which are bad news for longevity.

In order to reduce these temperatures, Trionic will use fuel dumping ie injecting more fuel than can be burnt in order to allow the unburnt fuel to act as a "heat soak". The down side of this is that it robs power by impairing the combustion process. Water does this much more efficiently and allows a better burn as it has a far higher SHC per unit volume than fuel.

I've installed an Aquamist 1s system on my 93 9000 2.3T. The primary reason for doing this was that I was running the same sort of pressures as you- but with an MBC, so I'd had my APC eliminated. The water injection was there as a protective measure to prevent pre-ignition and ensure EGTs didn't rise too high as I knew I would be at or about the limit of what the stock fuel system could deliver.

In terms of an improvement in performance on your car, I would say fitting the water injection would be a lot less significant than an uprated intercooler. Uprating my intercooler was one of the most noticeable improvements- and, from a protection point of view, it's very simple mechanically and there's not a lot can go wrong!!


I'm expecting my Stage 5 upgrade from Maptun soon, which offers around 350hp. After it arrives, I'm going to book a tuning session at the rolling road where I can measure fuelling, EGTs and so on and thus be able to adjust the injection for optimum performance/protection.

I shall try it using a 50/50 water/isopropyl alcohol mix as this is reckoned to provide a further performance enhancement. I will experiment with injector sizes to find the optimum value.

When done, I shall write up my findings and publish them.

But, to reiterate the main point: go for the intercooler first.
 

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Discussion Starter #3
Thanks for the advice, Mark, much appreciated I believe I will be installing the Viggen IC first, then perhaps looking more into WI in the future. Good luck with your Stage 5 -- I'm green with envy
 

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Not entirely (although in Pyronerd's case I would replace the stock IC with the Viggen one, but that has to do with restriction and the resulting pressure drop rather than cooling itself!).

It's like this.

An intercooler cools the charge air. Cooler charge air is denser, so more fuel can be burnt, which results in higher cylinder pressures equates more power and higher combustion temperatures.

Water injection (1) cools the charge air and (2) controls in-cylinder combustion temperatures -effectively preventing detonation - whilst an IC can only do (1).

Huge intercoolers have one big drawback - they increase the amount of air between air filter and throttle housing, which negatively affects throttle response. Which is the Achilles' Heel of turbocharged engines anyways, whilst getting big power from them is hardly a problem!

Therefore I would size the intercooler (the cooling effect of which is quite dependable) so that if everything else fails, still reasonably high boost levels can be reached before detonation, and achieve the rest via water injection.
 

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Eric, this is a biggy, and I'm not going to disagree with you on the problem of large mass intercoolers... however I can report that fitting the Abbott intercooler to my 9000 significantly reduced spool up times and increased throttle responsiveness.

I believe this is due to
1) a reduction in internal resistance
2) more efficient cooling

Certainly, now it is fitted, although I get quicker response, in summer the temperature gauge runs hotter, presumably because the intercooler is taking a greater degree of the cooling capability out of the incoming air, and leaving less for the radiator (this weekend's project- install an EWP
)

The only bit of what you say that doesn't stack up for me is about an uprated IC not affecting combustion temperatures/detonation.

Detonation is caused when the temperature of the fuel/air mix due to compression reaches flash point. The increase in temperature is proportional to the increase in pressure, ie how much you have reduced the volume of the gaseous mix. Given that the change in volume is the same regardless of starting temperature, I think I'm right in saying that the temperature increase will be the same for any gaseous mix compressed by the same ratio. Thus if the mix starts out cooler, it will end up cooler at the end of the compression.

So, in a round about way, a more efficient intercooler will in actual fact help to reduce combustion temps, although nowhere near as effectively as water.
 

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 Detonation is caused when the temperature of the fuel/air mix due to compression reaches flash point. The increase in temperature is proportional to the increase in pressure, ie how much you have reduced the volume of the gaseous mix. Given that the change in volume is the same regardless of starting temperature, I think I'm right in saying that the temperature increase will be the same for any gaseous mix compressed by the same ratio. Thus if the mix starts out cooler, it will end up cooler at the end of the compression.[/b]
True enough when we're pushing the same amount of oxygen into the engine, which in the case of a more efficient intercooler means lower boost pressures. But if you are pushing the same air volume into the chambers before and after the IC upgrade that will mean more oxygen in the latter case, which in turn mill mean more fuel to be burnt, which equates to more power. Unfortunately this also means we are closer to detonation range again, effectively redressing the balance, albeit at a higher power level...

Also I believe the Abbott IC not to be bigger than the stock item, just a lot more efficient in terms of restriction/pressure drop. So my former argument does not apply to your case. It does however apply with giant front mount IC's replacing smallish c900 items. In that case you buy a big power advantage with a possible increase in throttle lag (especially when replacing said IC with the worse-flowing OE 9000 design), whereas a proper water injection system in conjunction with the stock IC (which is not so effective in cooling, but flows pretty decently), in my case improved with a fancooler kit, would be more a case of cake consumption and retention at the same time...
 

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Ah! You see, we do speaka da same lingo!

A physically bigger intercooler will indeed give more absolute power, but at the expense of response- and as we've said so before, it's the change in response that matters so much on a turbo engine, which is why things like air filters, free flow exhausts etc..although giving the same absolute power increases as for NA engine, will result in a much bigger real time dynamic response or, put another way, more
when you plant the pedal on the floor

But just to avoid confusing Pyro and to summarise what we've said: there's no significant size increase in going for the Viggen IC, but there is a reduction in flow resistance and improvement in cooling, so you will get a big benefit.

[edit]

Oh, I do believe the unit of consumption here is the pie, BTW!
 

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I would say the biggest benfit from the Viggen IC is the better flow. On the stock IC, the air goes through half the cooler one way and the other half the other way, so the flow capability increase is huge for the cross-flow/Viggen IC.

Anyways, I would go for the Viggen IC first. The better flow gained my car 11 hp and 14 Nm.

The best thing I gained from the water injection was the much improved hot weather performance. So, pyronerd, as you live ina rea that gets pretty hot in the summer, you will feel the difference in the hot weather performance. The power just won't fall of so much like it does without the water.

I too, will be taking advantage of the water injection here in a month or so. I will be going down to Hirsch to get my ECU reprogrammed. Since the first ECU upgrade, I added the Viggen IC, a 3" downpipe and the water injection, so Hirsch thinks they can find a good power increase from another reprogram. I'll let you all know how it goes.

Eric Burr
1999 9-3
 

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Discussion Starter #9
Interesting to read all the discussions All makes sense, too, so cheers for you lot.

Hopefully I can afford the Viggen IC pretty soon, and then be able to save up for the Aquamist S1 by summer ($439 US through a retailer not to far from me, cheaper than I expected).
 

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The Aquamist 2S system has been a key element in enabling me to reach and sustain high boost levels with my '94 9000 Aero. If you look at the dyno runs I have posted at my site (www.kyankton.net), you can see that the first run with the Abbott ECU tended to spike more. Once I installed the water injection (and changed ECU's to the SQR), the boost application was more consistent.

I have the Abbott intercooler installed and it does provides some moderate benefits over the stock unit. However, if I were to spend the money again, I would probably install one of the KJ units.
 

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KevinY,
Nice car..... nice website...... hang around on this forum, I'm sure you'll be able to contribute significantly.

San Jose eh....that's a co-incidence, my best friend of 20 years (and a ex-Saab owner) emirgrated to Campbell, Ca. just before Christmas, that's not that far south of you.
 

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I thought I would jump in here too since I often you the lot of you on the SaabNet. Its good to get a different perspective some times. One thing I can tell you off the top is that you guys go for alot of the Abbott stuff. This strikes me as strange since you are closer to Sweden than us Yanks, but you choose to you with the home grown parts. The trend I noticed in the US is that people have backed away from Abbott parts due to rich running ECU's experiences and high prices relative to other parts. However, some of Abbott's stuff is like a piece of art. For example, the rear shock brace that I installed I think adds more in looks that it does in overall effectiveness. I posted another topic and would be interested in getting your opinions on the my next project.

Cheers!
 

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Kevin,
I think the trend now (in the UK certainly) is for going to the Swedish tuners for ECU/Engine bits, but because of their racing background, Abbott are probably still tops for chassis mods.
Also, for a lot of people who don't like getting their hands dirty.. Abbott are very convienent for offering a one-stop, supply and fit service...
 
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