water injection with sc12 high boost press

[stepan117]

Has anyone looked into or tried to run water injection to cool an SC12 running higher than 15psi boost ?
I have a 175mm crank pulley and a standard small size pulley running at 14psi . I have now a 103 S/c pulley to fit which my guess is gunna increase the boost to 17-18psi.
Thinking of the teflon coatings i was looking into fitting a water injector just before the s/c and operating it with the voltage for the clutch engagement.
Any feed back appriciated

[fixeruperer]

yes it will help, but 14psi on a sc12 is pretty much its limit anyway, yeh youll get 18psi but it just doesnt have the volume of air to match rpms.

you need something bigger.

[oldcorollas]

thats mainly because of theheat, but if the water is pulling heat out, you'll get a higher % of the theoretical air...

still probably hot though.. and worth taking temps with/without water

[stepan117]

i was going to make a 2 1/2" pipes from the outlets on the s/c with new flanges to help with increased pressure and volume and run it through a water to air intercooler.Also i am running a EMS ecu so i'll se what dyno tuning helps with it also.

I have a couple of s/c laying around so i guess i'll give it a try and see what happens.

I am in the midlle of building another GZE with a GT30 turbo and NOZ for drag and was looking into running a VW TSI twin charge set up for street use .

[JustenGT8]

yes it will help, but 14psi on a sc12 is pretty much its limit anyway, yeh youll get 18psi but it just doesnt have the volume of air to match rpms.

you need something bigger.

err that's not quite right mate. It's a roots SC so the faster you spin it the more air in moves. You are pushing it outside it's vol efficiency but, the bigger issue is the safe rpm for the blower itself. With water injection you'll get the heat and eff back under control somewhat (as OC says it'll need some testing) but if the rpms are beyond the design limit then bad idea.....i suspect they are but i'd at least be doing the calcs to see what rpm you'll be pulling and post for views on how safe they are.

[Radar]

Curious could you just put more oil in the SC and run an external oilpump/oilcooler/thermofan setup to try and keep the SC cooler?
After all if you had water injection, and you get your motor mapped accordingly, what happens when the water runs out and your half way through a hills cruise?

[Norbie]

It's not the heat of the SC itself which is the problem, it's the heat of the air being compressed. Keeping the SC cool will have very little impact on this.

[Billzilla]

You'll get more boost if you fit it to a smaller engine.
HTH.

[Duk]

At 17-18psi the old straight lobed supercharger is going to have some pretty massive internal leakage.
Water injection may help precvent some of that internal leakage tho.
I did fit a pre SC water injection system but I never had a boost gauge fitted to see if the water helped at all with SC sealing/exstra boost.
Now it helps absorb some of the heat from the turbo air but I don't have any air temp sensor to do any data logging from so I can't comment about it's effectiveness on my car.

[e30-323ti]

You'll get more boost if you fit it to a smaller engine.
HTH.

Or a bigger SC, say an SC14 !?!?!

[stepan117]

ye i was thinking of an sc14 but this is just a fun mod i was gunna try out of curiosity whilst i'm building this gt30 with NOz
I had last year the sc12 running at 14psi with a 70jet wet system NOz set up and got 210hp on the dyno but NOz was costly and also worrying with the cops on the street in Oz.
I found at night it was ok cuz of air temp but a waste of time during the day.

any ideas what the boost will be guys?
175mm crank pulley and 103mm s/c pulley (20mm smaller than the small std one) i can only guess just now on approx 17-18psi

By the way this 4agze is in a pocket rocket mk1 mr2 , lsd g/b , lots of fun so far

[oldcorollas]

123-103mm pulley?
123/103*100% faster =20% faster = theoretical 20% more boost

175mm = NEVO = 14psi?
theoretically you would get 16.7psi...

[Ben Wilson]

I used to run water injection pre supercharger on my mr2. For some reason it refused to make over 10psi even with a Nevo pulley, but according to the tuner it just loved advance at high revs. It did run very nicely and there was no damage that I could see to the supercharger.

[stepan117]

what was the highest boost you ran?

[Ben Wilson]

Not sure if it was the water cooling the charge and reducing the pressure or what, but the highest I ever saw was 10psi. It did make 130kW at the wheels though...