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  #1  
Old 19-06-2007, 12:23 AM
keithmac keithmac is offline
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Default "Best" mixture for port water injection?.

I`m currently running a 6 0.3(75cc) jet setup on my V6 Twin Turbo, the jets are approx 3 inches away from the intake ports. At the moment I`m running a 30%methanol 70% water mixture and I`ve leaned the fuel out slightly to suit (net 12:1 afr).

I`ve been reading up on different mixtures and I`ve heard a lot of conflicting information. My goal is soely knock control, any inlet air temp cooling is a bonus. a 50/50 mix seems to be the best starting point, but then I hear that straight water is better due to it`s higher cooling capacity, but then methanol evapourates quicker and can aid cooling..

Cost is another factor, a 30m70w mix is twice as expensive for me than straight water and I get through 16l to a tank of fuel if my right foots itchy! I don`t mind spending the extra if the methanol is really benificial but then again I don`t want to pour money down the drain!. Water is 20% by volume of the fuel injected (2200cc/min of fuel at peak flow).

Anyone care to shed any light on my situation, would like to here from people running direct port setups but there doesn`t seem to be many around for some reason?, any comments are welcome.
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Old 24-06-2007, 07:18 AM
JohnA JohnA is offline
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A few people have settled down experimentally to around 70water/30meth as a compromise of in-cylinder cooling and atomisation/octane booster.

Your water/fuel ratio is higher than average and you shouldn't have any cylinder distribution issues (where methanol helps) so I guess ambient temperatures would be another deciding factor for your mix. In the summer maybe a bit more meth (for the extra charge-cooling effect)

Have you ever seen any hint of detonation with your setup?
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Old 25-06-2007, 05:06 PM
keithmac keithmac is offline
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Hello John, thanks for the input.

Originally before any water I had bad detonation and had to pull 6 degrees of timing which really dampened the engine down, I then tried injecting the water before the throttlebody and still had detonation problems (I'm assuming that was down to my log style manifold).

With my port setup and 30meth/70water I`ve been able to add back the 6degrees of advance and it isn`t detonating, think I`m just going to leave it be at 30m/70w as it seems to be doing the job. The methanol is pobably more use as an octane booster rather than charge-cooler in my setup.
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Old 27-06-2007, 08:12 AM
JohnA JohnA is offline
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Quote:
Originally Posted by keithmac
... The methanol is pobably more use as an octane booster rather than charge-cooler in my setup.
Methanol in the mix helps reduce the surface tension, so atomisation is better.
This isn't as crucial in port injection, but it helps. :smile:

20% of 2200cc/min is 440cc/min. Are you sure your pump configuration can support this much? If so, then you're having roughly 140cc of methanol mixed with 2200cc of fuel under those conditions - percentagewise it isn't very dramatic and neither will be the octane rise. But it's nice to have under boost anyway :smile:
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Old 28-06-2007, 07:19 PM
keithmac keithmac is offline
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Hello John, I`m running a race pump with primer and 6 75cc/min jets. I tested it with battery voltage at 12v and was getting 450cc/min into a jug, may be more with the car running and the voltage up to 14v but there`s the boost pressure at the nozzle which would porbably cancel that out.

Wideband looked like the meth was making the afr`s 1/2 a point richer, will have to have another look into that, as you say the amount of meth injected is a drop in the ocean compaired to the fuel going in!.

If I ran pure meth it`d only be 20% meth to fuel ratio, I`d need to pump a litre/min in to make any real dent I suppose!.
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Old 29-06-2007, 08:15 AM
JohnA JohnA is offline
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Quote:
Originally Posted by keithmac
Hello John, I`m running a race pump with primer and 6 75cc/min jets. I tested it with battery voltage at 12v and was getting 450cc/min into a jug,..
Ah, looks like you are indeed running this volume then, with the primer pump and all. :wink:

Yeah, if I had a mitsubishi TT I'd definately go for port WI, it's the only way to keep it from misbehaving under high boost Left alone, the cyl bank next to the bulkhead does feel a bit hot under the collar, doesn't it? :shock:
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  #7  
Old 02-07-2007, 07:09 PM
keithmac keithmac is offline
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Yeh the rear bank does get toasty warm after a hard run!, they`ve also got a tendancy to let go on number 6 cylinder which is the last in the line for fuel supply.

Port injection`s worked very well with it, I`m leaving it be for the time being but if I go for bigger turbo`s I`ll be looking into higher volume port injection, Shurflo pump with Aqamist fittings I think.

I was a bit dubious going for port injection, but it was worth the effort.

The primer pump is an amazing upgrade for the Erl pumps, before 330cc/min was it`s limit and it can flow 600cc/min after the primer depending on jetting..
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Old 16-11-2007, 04:25 PM
Pit Viper Pit Viper is offline
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I realize this is an old topic, but I wanted to get a little input.

I have 2003 Dodge SRT-4, with a 2.4L turbocharged engine.

I'm currently running an Aquamist HFS-5 system, with a 4-scroll 0.3mm nozzle (98cc) at each intake runner, and a .5mm nozzle just after the intercooler. I'm running 680cc fuel injectors.
With this setup, I'm still getting some knock running a 50/50 mix of water/methanol and 91 octane fuel. Unfortunately, that's the highest octane I can get here, other than race gas.

Would it make sense to increase the nozzle sizes at the ports, and reduce the one for the air charge?
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  #9  
Old 16-11-2007, 05:21 PM
JohnA JohnA is offline
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Quote:
Originally Posted by Pit Viper
....Would it make sense to increase the nozzle sizes at the ports, and reduce the one for the air charge?
I'd think it's certainly worth trying.
0.4mm nozzles are less prone to blockages as well.
I wouldn't think that the post-intercooler nozzle adds much under these conditions, yet lowers the available pressure for the other ones! (they need the pressure for good atomisation).
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  #10  
Old 17-11-2007, 11:19 AM
keithmac keithmac is offline
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I found after a bit of testing 75%methanol - 25%water mix was best for my engine to control knock (flowing 1.2l/min), I changed to a Shurflow pump. My engine must be octane limited by the looks of it, I run BP Ultimate petrol - 97 ron or slightly higher. 10psi and under it needs no det control, after that I need something to stop knock or else I have to retard timing 6 degrees which kills the power/ engine responce.
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