[Mk2] [Turbo] Water/meth injection

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Tsia
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Location: Milton Keynes

Re: [Mk2] [Turbo] Water/meth injection

Post by Tsia »

I thought progressive kits only responded to boost level? I.e. you dial in minimum and maximum boost and it just changes the flow accordingly, irrespective of RPM.

Edit: therefore if true, 1.3 bar @ 3500 or 7000rpm will have the same water/meth injection, even with progressive?
jimGTS
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Location: North Kent

Re: [Mk2] [Turbo] Water/meth injection

Post by jimGTS »

shinny wrote:
jimGTS wrote:unless you have progressive BOOST, then no its not valid.

once you hit 1.3bar, it injects the same amount, no matter at 3k rpm or 7k rpm.
so no its not the same as fuel injectors.


But 1.3bar boost at 3500rpm is only consuming air at half the rate as 1.3bar at 7000rpm. So if you're injecting the same rate of water/meth for both then you're actually injecting twice as much per cylinder stroke at the lower RPM than at the higher rpm... right? Or are non-progressive kits still reading the engine RPM and reacting to that?


not injecting twice as much, just ingesting the same amount much more quickly?
very few kits, if any (i havent done a search), inject based on rpm.
Tsia
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Location: Milton Keynes

Re: [Mk2] [Turbo] Water/meth injection

Post by Tsia »

And one more question - what sort of cc/min nozzles are you guys running? With the AEM kits I'm seeing an option of 250, 500 or 1000 and haven't the foggiest which I'd need to use.
shinny
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Location: Reading, UK

Re: [Mk2] [Turbo] Water/meth injection

Post by shinny »

jimGTS wrote:
shinny wrote:
jimGTS wrote:unless you have progressive BOOST, then no its not valid.

once you hit 1.3bar, it injects the same amount, no matter at 3k rpm or 7k rpm.
so no its not the same as fuel injectors.


But 1.3bar boost at 3500rpm is only consuming air at half the rate as 1.3bar at 7000rpm. So if you're injecting the same rate of water/meth for both then you're actually injecting twice as much per cylinder stroke at the lower RPM than at the higher rpm... right? Or are non-progressive kits still reading the engine RPM and reacting to that?


not injecting twice as much, just ingesting the same amount much more quickly?
very few kits, if any (i havent done a search), inject based on rpm.


I've not really investigated injection kits, so I'm just thinking it through. My point is, however, that given a constant injection rate and a constant boost, the amount of water/meth actually in the cylinder during a single ignition decreases as the RPM increases.
Dale_V
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Re: [Mk2] [Turbo] Water/meth injection

Post by Dale_V »

shinny wrote:
jimGTS wrote:
shinny wrote:

But 1.3bar boost at 3500rpm is only consuming air at half the rate as 1.3bar at 7000rpm. So if you're injecting the same rate of water/meth for both then you're actually injecting twice as much per cylinder stroke at the lower RPM than at the higher rpm... right? Or are non-progressive kits still reading the engine RPM and reacting to that?


not injecting twice as much, just ingesting the same amount much more quickly?
very few kits, if any (i havent done a search), inject based on rpm.


I've not really investigated injection kits, so I'm just thinking it through. My point is, however, that given a constant injection rate and a constant boost, the amount of water/meth actually in the cylinder during a single ignition decreases as the RPM increases.


yup

or if you want to look at it from the other way... is too much before the rpm increases :-$
androo007
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Re: [Mk2] [Turbo] Water/meth injection

Post by androo007 »

I use a 500 cc nozzle. Light mist at 8psi and full spray at 20psi+

There are progressive kits but cost a lot but imo would only get if I was mapping with safeguards etc. I just have it fo safety.


It reduces torque a little and power in reality......but worth it as a safety net.
Tsia
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Joined: Fri Sep 23, 2011 9:12 pm
Location: Milton Keynes

Re: [Mk2] [Turbo] Water/meth injection

Post by Tsia »

Thanks - I'll opt for a 500cc then. Thing is, I'm running 1 bar currently, which I'd like to bump up to 1.2 post WI, so overall it'd be a net gain in power I'd like to think :)
jimGTS
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Location: North Kent

Re: [Mk2] [Turbo] Water/meth injection

Post by jimGTS »

Guides advise on nozzle sizes based on power output.
Not sure of size of mine specifically, but I got the size rated for 300ish hp.
Though I believe I’m running a bit more than that.

Am sure a google you’ll find the size you need.
Dale_V
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Re: [Mk2] [Turbo] Water/meth injection

Post by Dale_V »

I made 20bhp from a 500cc nozzle, it allowed the timing to be advanced a couple of degrees, and that was before I took out some injector fuelling to compensate for the meth richening the map up. that was at 450bhp. increasing the jet to 1000cc didnt give any gains, except waste water/meth.
androo007
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Joined: Mon Mar 03, 2014 1:43 pm

Re: [Mk2] [Turbo] Water/meth injection

Post by androo007 »

Ah so yours is mapped in then dale?

I just have mine for hot days where iat may climb
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