Water Injection on a Stage 2+

GruvenS4 · 10-13-2005, 06:12 AM

My mechanic is trying to sell me a water injection system for my Stage 2+ S4 (chip,cat back exhaust, I think that makes it a 2+). Does anyone have experiences with these? I don't know the brand name on it, but it's around $300 and is relayed with a pressure switch to come on a a preset boost level. It comes with a gallon reservoir. I've got experience with nitrous, but never with water injection.

Thoughts??

~DonQPremiumTequila~ · 10-13-2005, 07:21 AM

GruvenS4 · 10-13-2005, 08:01 AM

Hey, Mark P, what are you thoughts?

Flyboy · 10-13-2005, 08:40 AM

are horrible, don't bother. The only benefits I've seen is that on a dyno, where the IC's aren't getting the usual cooling, the W/I helps to offset heatsoak. On the road, the W/I will help to keep the IAT's from rising as fast after about 5000 rpm.

But on the flip side, you have the potential to lower performance with W/I if the car is running correctly without it. Back to my first point, if the software isn't tuned to take advantage (higher boost, advanced timing, leaner AFR) I don't think it is worth it.

rojodosformula::red · 10-13-2005, 09:46 AM

and using a fuel injector to pulse the spray. You would have 100% rpm/injector duty cylce control and for a lot less than the aquamist set up =) Plus you get slightly more fuel control and adjustments on the fly as a benefit to the emanage. This might end up being my winter project. I have a friend with a turbo fiero who is looking to go the same route.

silvino · 10-13-2005, 10:07 AM

Water helps fight detonation yet doesn't promote good combustion which will hurt power.

Methanol cools intake charge and raises ocatane. The only issue I have in general with injection kits is that you don't know how evenly distributed the methanol/water/whatever will be.

Mark P · 10-13-2005, 10:54 AM

For the Aquamist system I got, pricing was up around $900. It does help, but at that cost, I have a hard time saying it was worth it.

I wasn't too fond of the basic system that is merely On/Off with just a pressure switch. This means that it's either going to be adjusted to flow too much at lower RPMs or not enough at higher RPMs.

The 2D system I have monitors the fuel injector flow so it increases water with more flow, which follows the MAF flow as well (w/relatively flat A/F curve).

With that system, here were some results I observed on the dyno:

below data is 4 runs on the dyno, 2 with AM on, 2 with it off...

Ton of data on my website too:

http://ctny.audiworld.com/mark/s4/aquamist/

Flyboy · 10-13-2005, 11:12 AM

Methanol does not cool in-cylinder as well as water, which is where W/I is going to give the biggest benefit. While it may increase the effective octane slightly, it has less than half the net energy content of gasoline. There are a number of things to consider, and there is not a one size fits all answer to what mixture should be used.

GruvenS4 · 10-13-2005, 11:27 AM

a 50/50 mix in the cars he's installed it on (STI, a few Eclipse GS-T's) with a relative amount of success. It would seem that most chips on the market automatically retard the timing when the sense an oncoming detonation.

I am running stock IC's and probably will always run them unless I go the full stage 3 (not likely).

silvino · 10-13-2005, 11:40 AM

Methanol cools intake temps which is power, period. It dramatically cools intake charges to the point some people have run efficiently without a restrictive IC that is normally needed to keep intake temps reasonable. Lower intake temps also helps keep detonation under control in some circumstances.

It is true though that you do need to use more methanol than you would a race fuel equivalent BUT you only use it at WoT which many guys have proven isn't so bad (filling once per week on HIGH hp cars using a reasonably sized container under hood). When you drive around on race fuel you waste fuel just sitting at a light or during light cruise. The Methanol wuold be triggered only when enough boost is seen.

FYI, look on the aem forums as well. Many of the Supra and other cars runnning methanol have high resolution, accurate logs of their proof and none of this stock ecu crap that is vague.

I'm sure you'll be happy once you realize how mistaken you are.

Oh wait, one last bad thing about methanol. Methanol IS indeed dangerous to have should you get into an accident and high heat/flames are near.

10-13-2005, 06:12 AM	#1
GruvenS4 New Member Account #: 73341 Join Date: Apr 2004 Posts: 87	Water Injection on a Stage 2+ My mechanic is trying to sell me a water injection system for my Stage 2+ S4 (chip,cat back exhaust, I think that makes it a 2+). Does anyone have experiences with these? I don't know the brand name on it, but it's around $300 and is relayed with a pressure switch to come on a a preset boost level. It comes with a gallon reservoir. I've got experience with nitrous, but never with water injection. Thoughts??

10-13-2005, 07:21 AM	#2
~DonQPremiumTequila~ AudiWorld Super User Account #: 68023 Join Date: Jan 2004 Posts: 6,176	Ask Mark P i am pretty sure he has water injection. __________________ 01 S4 6-speed stage 3.5 95 S6 avant very stock.. sold 95 90 quattro 5 speed winter car MK3 (L322) Range Rover HSE full size with mods Leader of the Anti Windows mobile militia Blackberry pimp..... NOW WITH the 3G IPHONE :-)

10-13-2005, 08:01 AM	#3
GruvenS4 New Member Account #: 73341 Join Date: Apr 2004 Posts: 87	Re: Ask Mark P i am pretty sure he has water injection. Hey, Mark P, what are you thoughts?

10-13-2005, 08:40 AM	#4
Flyboy AudiWorld Super User Account #: 4736 Join Date: Apr 2000 Posts: 3,521	Unless you plan to have some custom software tuning done, or your IC's are horrible, don't bother. The only benefits I've seen is that on a dyno, where the IC's aren't getting the usual cooling, the W/I helps to offset heatsoak. On the road, the W/I will help to keep the IAT's from rising as fast after about 5000 rpm. But on the flip side, you have the potential to lower performance with W/I if the car is running correctly without it. Back to my first point, if the software isn't tuned to take advantage (higher boost, advanced timing, leaner AFR) I don't think it is worth it.

10-13-2005, 09:46 AM	#5
rojodosformula::red Senior Member Account #: 71729 Join Date: Mar 2004 Posts: 5,879	I've been kicking the idea around of using a greddy emanage as a contoller.... and using a fuel injector to pulse the spray. You would have 100% rpm/injector duty cylce control and for a lot less than the aquamist set up =) Plus you get slightly more fuel control and adjustments on the fly as a benefit to the emanage. This might end up being my winter project. I have a friend with a turbo fiero who is looking to go the same route. __________________ ----------------------------------------- Formula red NSX-T Tein Mono flex coilovers NSX-R chassis bars Dali SS exhaust Dali ram air/ Uni filter/ SS shifter/ Leather Sparco Milanos Volk GT-P wheels CF NSX-R spoiler Viva la please use the classifieds! Riebes Auto Parts in Loomis, CA can suck it. Thanks for the help bitches.

10-13-2005, 10:07 AM	#6
silvino New Member Account #: 96333 Join Date: Aug 2005 Posts: 325	Junk unless you get a system that lets you spray methanol which IS worth your time. Water helps fight detonation yet doesn't promote good combustion which will hurt power. Methanol cools intake charge and raises ocatane. The only issue I have in general with injection kits is that you don't know how evenly distributed the methanol/water/whatever will be.

10-13-2005, 10:54 AM	#7
Mark P AudiWorld Expert Account #: 139 Join Date: Mar 2000 Posts: 27,948	mixed review.... For the Aquamist system I got, pricing was up around $900. It does help, but at that cost, I have a hard time saying it was worth it. I wasn't too fond of the basic system that is merely On/Off with just a pressure switch. This means that it's either going to be adjusted to flow too much at lower RPMs or not enough at higher RPMs. The 2D system I have monitors the fuel injector flow so it increases water with more flow, which follows the MAF flow as well (w/relatively flat A/F curve). With that system, here were some results I observed on the dyno: below data is 4 runs on the dyno, 2 with AM on, 2 with it off... Ton of data on my website too: http://ctny.audiworld.com/mark/s4/aquamist/ __________________ Mark P Current: '08 Audi A3 2.0T DSG, S-line - Ibis White - website - 25k miles '04 Porsche 911 Turbo, Speed Yellow - website - 29k miles '01.5 VW Golf 4dr 1.8T, Satin Silver, APR Stg3 - website - 203k miles '09 VW Tiguan 2.0T, Candy White - Hers Previous: '02 Audi S4 Avant, Imola Yellow, APR Stg3 - website - 191k miles '00 Audi A4 1.8T, Silver - Quattrobonium website

10-13-2005, 11:12 AM	#8
Flyboy AudiWorld Super User Account #: 4736 Join Date: Apr 2000 Posts: 3,521	I haven't read any studies that say W/I is 'junk' unless methanol is used. Methanol does not cool in-cylinder as well as water, which is where W/I is going to give the biggest benefit. While it may increase the effective octane slightly, it has less than half the net energy content of gasoline. There are a number of things to consider, and there is not a one size fits all answer to what mixture should be used.

10-13-2005, 11:27 AM	#9
GruvenS4 New Member Account #: 73341 Join Date: Apr 2004 Posts: 87	He has been using either 100% methanol or a 50/50 mix in the cars he's installed it on (STI, a few Eclipse GS-T's) with a relative amount of success. It would seem that most chips on the market automatically retard the timing when the sense an oncoming detonation. I am running stock IC's and probably will always run them unless I go the full stage 3 (not likely).

10-13-2005, 11:40 AM	#10
silvino New Member Account #: 96333 Join Date: Aug 2005 Posts: 325	Do a search on Supraforums for more hard data. Our guys have been switching to this to combat 91 Methanol cools intake temps which is power, period. It dramatically cools intake charges to the point some people have run efficiently without a restrictive IC that is normally needed to keep intake temps reasonable. Lower intake temps also helps keep detonation under control in some circumstances. It is true though that you do need to use more methanol than you would a race fuel equivalent BUT you only use it at WoT which many guys have proven isn't so bad (filling once per week on HIGH hp cars using a reasonably sized container under hood). When you drive around on race fuel you waste fuel just sitting at a light or during light cruise. The Methanol wuold be triggered only when enough boost is seen. FYI, look on the aem forums as well. Many of the Supra and other cars runnning methanol have high resolution, accurate logs of their proof and none of this stock ecu crap that is vague. I'm sure you'll be happy once you realize how mistaken you are. Oh wait, one last bad thing about methanol. Methanol IS indeed dangerous to have should you get into an accident and high heat/flames are near.

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