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View Full Version : WI on a Saab 9K Aero


Robert Davis
17-08-2004, 11:59 PM
Application: '95 Saab 9K Aero (U.S.-spec T5) with aftermarket ECU, 3" exhaust system, and K&N internal filter (stock replacement). Everything else is stock.

I've purchased a WI system, installed it, and am getting mediocre results. It contains a Shurflo 140-psi pump, 1-10 psi pressure switch, Aquamist 0.7 nozzle, anti-drain-back solenoid, relay, LED light for dash, and an in-dash switch for disabling the system.

The problem is that performance is little or no better in its best behavior and worse (lower boost and light misfiring) if the spray is activated too early. At this point I have it set for 10 psi and the performance level is about equal to no WI at all.

I'm getting a very good spray pattern from the Aquamist .7 nozzle, and the system is working very well. In winter the car is a race horse, achieving >20 psi with no trouble at any time, with no WI.

The problem is that the WI is not improving boost at the times I really need it, during summer months when temperatures here in Louisiana are 90?+ with high humidity. If I accelerate from low RPM (~2000) when it has just achieved operating temperature, as when the thermostat begins to open, I get decent boost, sometimes approaching 15 or more psi. At other times when detonation sets in it will boost to perhaps 13 psi, then back off to 11 or 12, presumably a reaction to detonation. It is not very consistent in this regard, but one thing is for sure--when ambient and engine temperatures are hot, boost is radically reduced. Whether or not WI is working seems irrelevant, as I can disable it at will using a swtich on the dashboard, and there is little or no difference on or off. I am using 93-octane (R+N/2) gas, the highest available here, and have tried different brands with no variation.

The WI nozzle is about 12" from the throttle body and is angled about 45? with the air flow. The Saab Trionic system regulates detonation using an ion-discharge knock sensor integrated with the spark plugs, but why doesn't the cooling effect of the WI affect this?

With the installation of the WI I was really expecting boost to climb to near-winter levels (>20 psi) even in the hottest weather, but I'm getting almost no benefit from this addition. What about adding some WSW fluid or alcohol to the mix? Any ideas would be appreciated.

hotrod
18-08-2004, 03:41 PM
Although you didn't state it explicitly it sounds like your running water only. I would suggest you go to a 50/50 mix of water methanol for your spray mix. In high humidity environments like yours, you will probably need the alcohol to get the effect your looking for. Some of the Buick GN folks run even higher percentages of alcohol with good success.

I personally do not like the windshield washer fluid but many get along just fine with it. When I used it on an intercooler sprayer I had never ending problems with nozzle clogging so choose not to use it. (they were very fine mist nozzles FWIW)

Larry

Robert Davis
18-08-2004, 07:21 PM
Thanks for the reply, Larry. I'm planning on trying to locate some methanol today and I'll post back the results.

SaabTuner
20-08-2004, 02:30 PM
I suggest a short test to see what the problem is. Here's why:

I have a 2002 Saab Viggen (T7 ECU) which also backs off the power during very hot weather. I live in Southern California where I'm stuck with CA91 octane. (Realistically it's more like 89 octane everywhere else.) I get very similar boost retardation to you. I have found a temporary solution for summer months that basically takes my octane rating to your level. That has eliminated any problems and gives me lots and lots of power. I suspect you have a different problem, but propose a way to test it out ...

Test: Buy some 100 octane fuel, 5 gallons of Toluene, or Torco race fuel in a can. If your boost goes up immediately after fuelling up with some high octane fuel you will know for sure that knocking is the problem.

If your boost does not change: Then your map from the tuner was conservative. This might be because the the tuners, living in Sweden mostly, do not have the right conditions to test your ECU in hot Luisianna weather.

If your boost does change: Then it was indeed a knocking problem. I would guess that it was either excessive heat from your A/C condensor (which sits in front of the radiator on your car) throwing too much heat onto the intercooler. Or ... that you need to move your nozzle farther away from the intake on the engine. Or ... that the combination of a VERY rich mixture and WI has caused your combustion gasses to burn so slowly that they're overheating the exhaust valves and causing hot spots which only make detonation worse. Hopefully the latter is not the case.

Just some thoughts on the matter. Try the test first. If octane makes no difference it's most likely NOT a problem.

Toluene can be bougt in 5 gallon drums from Sherwin Williams and Torco race fuel additive (which I use and is just about as good as 100 octane if you start with 93) can be bought here: http://www.need4speedpower.com./torco.html

Kevin Yankton also had some limited Success with WI on his 9000 Aero. With just the same mods as you plus an uprated intercooler and intake manifold he was running 25+ PSI on crappy CA 91 octane. So the WI just work, just a matter of figuring out why it isn't for you.

Here's his site: http://www.kyankton.net/9000index.htm

Adrian~

Robert Davis
20-08-2004, 09:46 PM
Adrian, thanks fo the post. I have been looking for a source for methanol lately, but the only hit was Sherwin-Williams who wants $23/gal. for it, so I passed. I thought I'd mix methanol and water (50:50) to the WSW reservoir (WI mix) on the advise of another respondent. What's the cost on a 5 gal. can of toluene? I suppose it isn't really that important in the interest of research.

I think you may have hit on something with the concept of a mapping error. Today I was getting very poor boost (~9 psi) with no indication of detonation, usually manifested as a peak and quick back-off of boost. This is the usual syndrome when the ambient temps and engine are hot. But occasionally the boost will go to 12 or 13, back off slightly to around 11, then move up slowly as RPM's increase. But on one occasion to day I hit 15 psi and it quickly backed off to 9-10 and didn't exceed that level the rest of the drive. I feel that something in the mapping is reading the heat from some source and tells the wastegate, "Don't boost beyond 10 psi, period!"

Keep in mind that I get excellent boost when the car is not heated up fully, like just as the thermostat opens. If I could locate the sensor that is doing this dirty work perhaps I could figure out a way to alter its feedback.

That said, I think you have a good plan and I'll try to implement it. Stay tuned.

SaabTuner
20-08-2004, 11:14 PM
Toluene is sold as a form of paint thinner. It should be about $5 a gallon if bought in 5 gallon drums. (Use all 5 gallons with one tank of gas. You'll about 99 octane if you do.) Make sure it's PURE Toluene as best you can. It's already in gasoline, so it shouldn't harm anything. Xylene works like Toluene as well if that's all you can find. However when using Xylene put it in BEFORE your fuel, then quickly pump fuel in to wash down the Xylene. If it's left in the fuel-tube it will corrode the rubber. It's not a problem once mixed with gasoline, but in high concentrations it's a problem. I found that out myself the hard way.

You could also buy that Torco stuff. It's only about $12 + $8 shipping or so. It's almost pure MMT (anti-detonant) and will take the octane with one can per tank from 93 to about 98. If this makes no difference, 100 octane probably won't either. I've used both.

Here are a couple other things to try:

1. If it's a mapping error you might be able to get around the error by moving the nozzle by the intercooler and then moving the temperature sensor up near the throttle body. That way the ECU "sees" the colder more dense air from the water injection.

2. I highly reccomend heat insulating your intake pipes. Especially with T5 as they are aluminum. I did my T7 plastic pipes and noticed an immense difference in hot weather: http://www.saabscene.co.uk/ubb/ultimatebb.php?/topic/23/970.html

The insulating wrap can be bought at nearly any local hardware store for like $5 a roll, and it should take between two and three rolls if you also do the intake before the turbo as well.

3. If it never freezes in the winter where you live, you might consider bypassing the throttle coolant heater: http://www.saabscene.co.uk/ubb/ultimatebb.php?/topic/23/974.html

T5 cars use a 1/2" tube to the throttle, T7 cars use a 1/4". Since that was my car (T7) you'll need a larger bypass tube. The coolant tubes are also located differently on T5, but you should be able to find them pretty easily.

Hopefully if all of the above techniques are implimented you will see much more power!

Adrian~

Robert Davis
21-08-2004, 02:18 PM
1. If it's a mapping error you might be able to get around the error by moving the nozzle by the intercooler and then moving the temperature sensor up near the throttle body. That way the ECU "sees" the colder more dense air from the water injection.

I thought about moving the nozzle close to the IC, but it seems it would delay the response since it would take longer for the water injected to make it up to the CC.

I have a heat sensor near the TB now, about 10" upstream. There may be another somewhere and I'll look around.

2. I highly reccomend heat insulating your intake pipes. Especially with T5 as they are aluminum.

That'll be easy to do so I'll give it a try.

3. If it never freezes in the winter where you live, you might consider bypassing the throttle coolant heater: http://www.saabscene.co.uk/ubb/ultimatebb.php?/topic/23/974.html

It does freeze here on occasion in winter, but the car is stored in a garage where the temp rarely falls below 50?F. This sounds like a good idea.

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hotrod
21-08-2004, 05:02 PM
For the methanol source, call around to shops that support serious racers. Alcohol class Drag racers and some circle track classes run pure methanol fuels. Here in Colorado I can buy fuel grade methanol at $2.25 a gallon at a local speed shop that sells fuels to racers as well as speed parts.

10 minutes on the phone should find you one. If all else fails call a local race track some of them even sell fuels at the track and one of the hard core racers should be able to point you to a source.

Larry