tedesco

last weekend I tried some waterinjection into the crossover. Plan was to speed up the spool of the turbo. The water takes some heat out of the exhaust gas but therefore evaporates and increases its volume a lot.
To keep things simple, I first tried the window washer and coonected it to the crossover but as I already thought before, the pressure the pump could reach was not sufficient. Next I tried another pump which was good for up to 4bar opperation. This time the injection worked but beside a bit of staem comming from the exhaust I could not realy feal any difference. This was just a very first attempt and quite crude as well. Did any of try something similar? Even if it does not change performance, I am sure that the exhaust gas temp will drop a lot. Important would be to fully evaporate the water before it reaches the turbo. Otherwise it would become "sandblasted".

Charlie944

Sounds like you are trying to create a steam driven turbine...my take on it and from what I understand about thermodynamics and STP gas laws is that you are better off trying to keep the heat in the exhaust to help drive the turbo. Turbo rely on heat energy and gas flow velocity to spool them up. Per design a turbo charger is a heat engine that turns otherwise wasted heat energy from the exhaust into useful work. Hence I would try to coat *Swain Tech coatings* the down pipe to improve thermal efficiency or reduce the length of the runner length the exhaust must take to get to the turbocharger. On my Callaway setup the turbo hangs right off the exhaust manifold which is a log style and has been ceramic coated. And this brings my boost threshold to right around 1400rpm.
You could also try retarding your timing to about 40 ATDC where most of the combustion process would happen within the exhaust manifold...that would get that turbo moving! But is extremley rough on valves and turbo components but has been used on WRC cars.

Keep experimenting though I am all for "in the name of science" tests!

Chris White

It would freak out the guys behind you on the track...!

samluke

I agree with 944T your going backwards. The goal is to keep as much heat in the exhaust before the Turbo. Porsche already put a lot of technology into the cars to achieve this. Ceramic liners in the exhaust ports, plus the dual skin/insulated headers and crossover pipe, non of which are cheap.

Where water injection works is on the intake side. Anything you can do to reduce charge temperature has the potential to increase power, so water injection into the inlet tract, or even infront of the intercooler can increase power.

toddk911

I guess injecting at the exhaust point would add pressure to aid in spool up???

But my understading is heat will aid spool up more.

But cheers for trying new ideas!!!

hally

thats a wild experiement tedesco! My wild guess would be that the effects would be in balance, is there some data out there that suggested a net benifit?

SD Porsche Fan

You could try injecting propane into the exhaust.

BOOM!

hally

kinda like an afterburner, that would solve our spoolup problemos

SD Porsche Fan

I wonder if the turbo could take it?

M Danger

isnt that basically what the rally guys do, just dump fuel into the exhaust to spool the turbo?

hally

kindof it seems, but sounds like they don't actually inject fuel directly into exhaust manifold
http://en.wikipedia.org/wiki/Anti-lag

M Danger

right, but you could, then again heck why not just put a spark plug in the exhaust and ignite what ever hasnet burned and that should help a tiny bit, I think im going to try it

Rogue_Ant

There is a reason that aggressive anti-lag rally cars changed their turbo every race.....


Rogue

M Danger

its not like youd be using it that same as rally racers

Rogue_Ant

Anti-lag (not water injection) is something to be cautious about... Porsche moved the turbo off the head to lower turbine inlet temps. By burning fuel in the header/crossover your dramatically raising those temps.

Does anti-lag work, sure, and with a mild set-up possibly nothing detrimental will happen, just exercise restraint.


Rogue