Water injection - before and after results?

The 1UZFE EGR Delete Kit is available for sale here.

20vseven

New Member
Messages
22
Location
Christchurch, NZ
I have upped the boost on my M90 supercharged 1uz from 7 to 11 psi. Good improvement in torque and power at lower revs but this falls away markedly above about 3500 rpm. Peak power before was 190 kW, now 200 rwkw - about the same as a stock LS1 on the rolling road I used.

I believe the reason for the drop in improvement is due to the heating from spinning the M90 so fast! There is no space for intercooling so water injection is the next thing to try.

I see several people have run various systems. Wondering if they have any before/after comparisons re air temps or power?
 

JustenGT8

New Member
Messages
2,432
Location
Canberra, Australia
I just used a common as muck surflo pump (120psi version I think), with nozzles from Aquamist. Nozzles are around $15 each but the best option I have found for atomisation.

Using the bigger M122 intakes temps were well over 100 deg C with no WI @ 17psi. With two nozzles pre TB and one in the plenum post SC we got temps down to 50 deg C....using water/meth. About 400cc/min of WI.
 

JustenGT8

New Member
Messages
2,432
Location
Canberra, Australia
Nah, just a boost trigger point via the ECU. staged control would have been better, via a solenoid valve or 2 but even in it's basic form it worked well enough
 

BlackUZZ31

Member
Messages
469
Location
Melbourne, Australia

20vseven

New Member
Messages
22
Location
Christchurch, NZ
Thanks for that.

The Gen 5 M90 map indicated it might still be near 50% efficient at peak revs but inlet temp still at 130C+ so plenty of scope for cooling here! Mine is probably an earlier version so less efficient/higher temps.

Agree a larger pulley/less boost would possibly give a better max HP but will reduce the power at lower revs when the supercharger speed is still moderate. I like wheelspin on demand. :)
 

cribbj

"Supra" Moderator
Staff member
Messages
4,795
Location
Houston, TX

20vseven

New Member
Messages
22
Location
Christchurch, NZ
Dynoed the car. Intake temps without injection were about 95C. Dropped to about 60C with the water /meth injection.

Added a couple of degrees timing to about 19 degrees (on 98 octane) plus pulled out some fuel as the meth had richened it a bit. However I had changed the muffler which had killed the power above 6000 rpm.

Max power went up from 202 to 206 kw - bit disappointing. Then I pulled off the air filter and power jumped to 219kW. Still dying above 6000 rpm so I'd better sort the muffler. Also lost about 1.5 psi boost - even without water injection so bit of a mystery there.

Conclusion - if I change back the muffler and sort a decent filter then I'm looking at a good 20 kw at slightly less boost. Overall making about 30% more torque than a 5.7L LS1 up to 4000 rpm on the same dyno. However I wonder how much I would have got earlier with a better filter........
 

20vseven

New Member
Messages
22
Location
Christchurch, NZ
Two jets fitted upstream of the throttle body - nominally rated at 600 hp. Just one jet dropped the temp about 25C so noticed the difference with the second operating. Probably better to fit at least one near the supercharger inlet so mist is entrained, not water flowing along the manifold walls.
 

20vseven

New Member
Messages
22
Location
Christchurch, NZ
Running larger Supra injectors. Exhaust is a bit freer flowing than stock but lengths are all over the place to make it fit. Changed the sound quite a bit though! As I said, If I sort the restrictive muffler then the power should be about 220 -225 rwkw - almost exactly what the spreadsheet on page i of this post predicts.

Also rolling road, not hub dyno so power isn't inflated.
 

Darby

New Member
Messages
13
Location
Christchurch New Zealand
Hey just been reading your post and thought why could you not run a liquid nitrogen cooler in your intake system before the supercharger because the hot air is quite thin as you well know and are trying to avoid. So why not super cool the air going in to make it as dence as posipal?

And any chance of seeing a pic of the engine bay?
 
Top