Over cooling a SC or turbo engine

The Aquamist forum has a lot of discussion on mixes of water/methanol and some guys are also mixing in nitromethane as well...

water/methanol mix evaporates faster than water alone, so absorbs heat during its evaporation.. question tho is there a certain temperature where such evaporation wont occur as readily to absorb heat which is'nt there.. like a well cooling FMIC setup.

I have run mine on previous FMIC core and it gave/retained top end power with 10-15bhp top end. Far more repeatable run after run. With the current core, which logs colder induction than previously, the aquamist contributed nothing on the dyno.

wondering what mix of water/meth/nitro becomes classed as a fuel !

 

When i was at goodwood i had a poke about a cosworth WRC engine
(zetec based) it had direct port water injection. EGT and knock for every
cylinder, aparently it could trim injection/ignition/water individually for
each cylinder to keep the entire engine running at peak performance
rather than limiting it by the weakest cylinder.

Water rail


The engine in question 300bhp 550lb ft (WRC trim):


Anyway, intercoolers, seems to be a lot of BS about mainly propogated by
people trying to pedal huge ones. I see robs point about the turbo
combating the pressure loss by increasing impeller speed to acheive the
same manifold pressure when experiencing a greater loss over the IC.
also that this could shift the turbo out of its effiecency range and how
this shift can put more heat into the intake.

how i understand it (gross over simplication i know) KPA and C used.


While we are talking turbo selection, lots of people seem to be pusing
small turbo's extremely hard, is this not putting them waaay outside their
adiabatic effeciency band? I have heard of people complaining of massive
lag when running larger turbo's and even running N20 low down to
combat it, but then u look at their downpipe:


Surely the install is just as important as component selection? No poin in
having coilovers if your tracking is out.
Edited by: Rallye

 

i had a chat to the cossie boys about this, they seemed to just use it to
cool in cylinder temps rather than charge temp, hence having it at the
port.

It does seem to do the trick though, from talking to the PSD/G-Werks
guys.

 

are you asking about water injection or intercooler fogging? (or both)


i would say water/methanol injection would be a perfectly reasonable addition to a performance car setup allowing additional control to prevent Det and chill intake temps.


IC Misting is likewise - however the most important thing with it is the control of the misting - IC misting has a *delay* before it can start affecting charge temp, so needs to be carefuly controlled so it's working when you need it, without being wasteful


Both have limits - they are finite resources, and the more you use them, the more weight they are adding to your setup.

Also you need to make sure the engine management has a *fail-safe* so that if you run out of fluid, get restricted flow, get a leak etc you don't find out with religious pistons.

 

Talking injection, like Aquamist system which is what I run. Misting is used on EVO's as I understand as std, and will help some thermal transfer no doubt.

Aquamist instructions suggest location of the injector, just after the IC outlet allowing as much distance hance time for heat absorbtion, so I guess their thoughts are also induction temp related with cylinder temp related being a bonus if there was anything left. Would explain my dyno results with and without it, on previous and existing core.

I know not IC related as such, but I was staggered when I saw in the flesh the use of NOS ona 1.8T on its induction temps.. started off hot 40-50'C and went to -8'C immediately the progressive gas control started.. at the end of the power run the temp had risen to 0'C One hell of a thermal shock to cycle on and off. Great coolant.. and fuel

 

Oversize cooler having same outlet temp?
Is this explained by higher p-loss across the core and extra work for turbo to do to achieve same tgt manifold pressure accounting for more temp load for it to deal with, hence nett zero gain. - Questionable core perhaps

System being a good match of components... as you say. Onkly as good as the weakest part of the system design.

 

yeah i know table isnt a true representation, i was just trying to put down
how i understand it writing.

 

I dont see why not, there is still al arger temp drop by the bigger core, but the inlet temp is higher due tot he turbo working harder.......

 

yea.. no nett gain, hence my comment questionable core.
in that scenario you would be dissapointed in the change

 

Yes questionable core, a core that is clearly too big

 

is it me,
or have several posts been deleted, shortly after goldens on this page???

 

I cannot believe what a bell end bill has made of himself in this thread!

you just do not argue with TT on subjects like thsi. he knows the facts, it's his job to know things like this, and he can back up all his "ideas" with cold hard fact and calculations.

just becasue you've bought a nice big shiney one (or 3) doesn't mean you know what you're talking about, and there's certainly no need to get all arsey about it and start sl*gging clearly more knowledgeable people off when they put you to rights.

just because you can afford to run 3 modified 1.8t it doesn't make you an expert on the matter.....

 

from my limited school boy physics isnt the cooler surface area to
amount charge cooled an exponential relationship? each time u double
the surface area the effect is less? (like db in sound) so surley it gets to a
point where the increased pressure drop over the core negates the effect
of the cooler charge?

 

I`ve been on the Vortex a few time recently and quite a few people use metanol injection instead of an i/c, usually comes on around 8 to 9 psi of boost?

Would have thought Supercharged intake temps would be a lot cooler as the air hasn`t been pumped though a hot turbo but I could be wrong?

 

well compressing air will always heat it, but how much onto top of that is
down to the effiency of the compressor. Yes the turbo will be physically
hotter, but if its more efficient at a particular flow rate and/or pressure
ratio it is quite possible for the turbo's charge to be cooler than the
superchargers. I think
Edited by: Rallye

 

Pray tell how this is (a) relevant how many 1.8T's I have had and (b) what business it is of yours..

I know what I have learnt from my ibiza and the examples of cores USED on my car, with the results they gave. The bigger one gave better results, but to most people this would be fairly obvious??

Wonder why RS500's had bigger FMIC than the normal Cosworths?
Edited by: badger-bill

 

one which has more losses across the core and happens to be bigger.

this is all very symantic and theoretical.

 

A larger core that has a larger pressure drop across the core.......


You're so wrong Bill its not even funny anymore

 

The cores in the picture I posted were small and larger.. smaller one had the greater pressure drop across the core. Thats what I saw. Larger one works better.. Torque request made from less boost... and much lower intake temps to boot. Now why is that not possible? Its what I have seen on mine..

Talking bigger is worse is all relative to what actual size your talking about. Mine is using the example of ACTUAL cores on my motor. In this instance the gains were what they were.

What you're trying to argue is bigger WILL give a bigger pressure loss.. well bigger than what exactly?

I'll stick with what works on mine.. do whatever you want to do.

 

Could it be because, jus at a wild guess, they arent the same engine???