[Mk2] [Turbo] some progress pics, GT3071R MR2

[T.F.S.]

The check valve cracks open at 30psi and does not make any serious difference to flow.

The pump operates at around 175psi (250psi pump but the more it flows the more the pressure drops) so it has no trouble overcoming the resistance of the valve.

2 systems would be better yes.

[T.F.S.]

Another D05/5gph injector added..hope to shave a few more degrees off the inlet temps on the next midnight run



I would guess that the temp just before the cylinder is a good 5 degrees lower than the temp i have recorded pre throttle body...IIRC atomisation suffers at under 30/40c so I have pretty much suceeded in what I aimed to do at this point and the extra 5gph injector is not needed really.

[T.F.S.]

Interestingly the extra injector didn't make a lot of difference...I expected in the region of 5-10c drop now we are injecting around 1350cc per min but it was more like 0c-1c. The system is not leaking and I am still wondering why we did not see a more significant decrease , could it be that no more methanol can evaporate into the airstream and I either need to increase water content or add another chemical into the mix?

I believe that 250cc is about the maximum amount of water I can inject into a 2.0 engine at this boost pressure..whenever I have tried to inject beyond that figure on this engine it has bogged or misfired so with a 10-15% water content in the tank on this run it would seem I am almost at that limit already

On a much longer run than normal on a 20c daytime blast we saw temps in the low 40's at high rpm and at one point just as I came off of the throttle a split second before I changed gear temps hit over 70c which again is not something I expected!

[Zemi]

It seems like you know the stuff. Great build.

[ashley]

I came off of the throttle a split second before I changed gear temps hit over 70c

Where are you taking your pressure reading for the water injection controller- from the manifold? Might be a crazy idea, but could you take it pre TB instead and that way avoid showing the water injection controller a vacuum when you lift off on the throttle...it would keep injecting between gear changes then?

[gavinda]

this is 1 of many reasons why i ended up going with a progressive controller that uses boost and injector pulse width to control my water injection pump/solenoid.
i wasnt happy with boost alone, not saying it doesnt work mind.
great build TFS.

[T.F.S.]

this is 1 of many reasons why i ended up going with a progressive controller that uses boost and injector pulse width to control my water injection pump/solenoid.
i wasnt happy with boost alone, not saying it doesnt work mind.
great build TFS.

Would make absolutely no difference, the throttle was closed, the injector duty was 0%

[T.F.S.]

Where are you taking your pressure reading for the water injection controller- from the manifold? Might be a crazy idea, but could you take it pre TB instead and that way avoid showing the water injection controller a vacuum when you lift off on the throttle...it would keep injecting between gear changes then?

I'm not sure if 70c off boost is a problem..less so with the throttle closed, it would be nice to spray during gear change but it might be enough to swamp the pipes with WM mix with the amount I am having to spray..

Having a separate system pre turbo that was plumbed up as you suggest might work well or full throttle gearchanges lol

[gavinda]

fair enough thought u meant off WOT not off completely in this instance

[T.F.S.]

Just adding this graph that a lot of you might find interesting.



It goes some way to show why it is that my engine is in one piece where other MR2 engines have simply gone pop...like I said in page one, its all about cylinder pressure and detonation.

The water cools the walls of the cylinder preventing the cracking some engines suffer, it cools the piston, it cools the inlet, lowers EGT, reduces cylinder pressure, increases the octane of the fuel, reduces knock.

When used pre turbo it also spools the turbo earlier as it changes the density of the charge, changes the mach speed of the compressor, allows the turbo to flow more/hold on to its power for longer and pushes the turbo towards an isothermic state.

If you also add methanol into the mix it just makes the turbo go mad!

Turbo cars need WI...

[badgerbob]

just read this from start to finish.......amazing work



and work i wish to copy

[T.F.S.]

No real updates this week due to the progressive controller failing again...
https://www.alcohol-injection.com/forum ... -3568.html

I had some time to fit the new pre compressor mount







Also the blades on the compressor are still suffering from wear..



Just waiting for a Coolingmist progressive controller to arrive so we can continue with the thread

[T.F.S.]

Another change to the pre compressor injection point and I have a feeling it may not be the last, the nozzle has been brought forward just over 1.5 inches..it is now within 5mm of the compressor nut, maybe this is too close for comfort?













Another change to the pre compressor injection point after noticing the wear on the compressor in the previous post and I have a feeling it may not be the last, the nozzle has been brought forward just over 1.5 inches..it is now within 5mm of the compressor nut, maybe this is too close for comfort?











It's not easy to strike a good medium with the injector placement...I think the previous nozzle position may have allowed the WM mix to hit the sides of the turbo inlet and pool into larger droplets which have damaged the blades as they have impacted, I dont know what is the best distance from the compressor but after rigging a very basic test I believe it to be 8-12mm away from the compressor thread/nut


Well I have a 3071 core sitting around due to a rough bearing, it's not easy to hold the injector and work out an exact distance for the best placement so I took a video to watch back afterwards.
Now as crap as this vid is it would seem that the best placement would be 8-12mm away from the compressor nut would you agree?

http://www.youtube.com/watch?v=OH9wbHRJ ... r_embedded

[ashley]

Not sure I'm going to proceed with my plans to inject pre compressor having seen this- not keen on risking this kind of damage at all

[T.F.S.]

Thats why you have a pre compressor injector that is half the size bud , I am using double the recommended size and trying to get it to work.

I also have a spare compressor wheel (these are also available on ebay for £30) so dont mind doing the R+D work.

[ashley]

[vtecpower]

You need to take me out on one of these midnight runs lol

[Kongaroo]

Londonish Midnight Wangan? Sounds a blast

Nice work Brian

So from your charts roughly how many degrees above ambient does the intake temp end up when cruising for extended periods of time off boost on the motorway? For eg. cruising at 3000rpm in 5th gear for 10 minutes.

I generally found with my intercooler setup the car will generally settle at around 13 degrees C above ambient (give or take) in the above situation.

After several boosted pulls to make the methanol spray I can get the intake temps back to be approx. ambient temps but as soon as the car stops spraying the intake temp will slowly rise back to be about 13C above ambient again at that speed.

[T.F.S.]

Mine is more like 35c above ambient mate, drops very quickly when spray kicks in though.

[kingsley]

Might be a crazy idea, but could you take it pre TB instead and that way avoid showing the water injection controller a vacuum when you lift off on the throttle...it would keep injecting between gear changes then?

A friend of mine had that setup on a Calibra Turbo. His was a fairly simple setup with the WI pump set to come on when boost hit a certain level (7psi seems to ring a bell somewhere).

The prob was that on part throttle, there wasn't much air flow (obviously), but in high gears there was lots of boost pre-throttle which triggered the WI to come on. The net result was that at part throttle in high gears (when pre-throttle boost was high but air flow was relatively low) the car used to bog. If he put his foot down it would pick up again. I told him I thought that problem could have been fixed by moving the pressure sensor to after the throttle plate but he never tried it.

To be fair I don't think the system was very carefully designed; prob more of a case of guesswork and see how it goes, but it did illustrate a point.

Cheers,
Kingsley.