I've been thinking about getting into the AI game once my setup is tuned/maxed out without it.

I'm running S5 internals with OEM housings and and seals. (1/2 bridged)
T04-R w/1.00
Haltech....750-1600's
bla bla bla

Reading the following :

http://www.aquamist.co.uk/phpBB2/vie...7db7b268de2a41

Got my mind cranking. I had thought about doing pre-turbo injection since I anticipate my intercooler will be maxing out efficency at the power range I'm going to need AI....but some of these "other" benefits such as compressor map alteration from the injection really seem like huge pluses.

Only problem is all their info is piston specific. I realize the turbo dynamics at least on the compressor side will be similar regarding the effects of this type of injection....but I couldn't find ANYTHING regarding using it and its benefits/drawbacks on a rotary. Again, talking specifically about pre-turbo injection.

If anyone has any experience, or knows of a decent thread with info about it that I may have overlooked in searching, fire it my way please

Thanks

 

My only concern with running any form of auxiliary injection before a turbo is that it will over time pool in the intercooler. This assumes you have one of course. Aside from that it's not a bad idea. I've seen people say that water damages the blades but this just isn't true. Many cars had carbs before turbos and gasoline never damaged them. It works fine.

As with anything there are advantages and disadvantages to this setup. My personal opinion, and others may disagree, is that if you are running an intercooler, run AI after it. Without an intercooler, run AI before the turbo. That steup makes the most sense to me. I would really like to see someone run without an intercooler and use Methanol injection before the turbo. Brian are you listening? Let's not get into the argument of which medium is better or wose. Try water there. I don't care. I just want to see it done on a rotary and actually pushed pretty good.

 

Its not pre-turbo, but its sans intercooler. I was on a television build-off a couple years ago and this is what the other team came up with. GSL-SE engine, S4 turbo, no i/c with auqamist. Ran fantastic!

I gathered that running with no intercooler extracts the most from the setup (not to mention the gains you'd see from direct plumbing!) but since my setup does include one, if I do it, it will be through a core

Maybe I'll install a pet-**** on the intercooler

So I'm gathering that this setup isn't widely used?

What about comments on the compressor map alteration apsect? bunk?

 

rotarygod,

I have been EXTREMELY tempted to try a setup like this. . .I'm just kind of scared to do it on my 3-rotor, which is presently the only turbo rotary I have. I would LOVE to not have a giant bulky intercooler, and just have my radiator getting all the love (fresh air) that my front bumper opening can provide.

Here's the question, how much water/methanol do you think needs to be injected to keep AITs in a range conducive to reliability & performance.

By my estimation, it boils down to the amount of heat generated in compressing the air, and then providing enough AI mass to absorb the heat such that the temps are what you'd like. For a mixture, the amount of energy that can be absorbed should be Mass(injectant1)*Cp(injectant1) + Mass(injectant2)*Cp(injectant2) for a mixture.

Assuming air flow rate (and therefore heat generated for a given flow rate at a given pressure) is a function of fuel consumption, with the air being consumed with the fuel at reasonably safe AFRs, the % of fuel that ought to be injected as AI is what I'm after. I realize it's just math, but I am not as confident in my thermo skills as I am in yours based on a few threads I've read. Also, I could be completely wrong in my thinking, so I'd really appreciate your thoughts on the matter.

I'm tuning on July 7th, there's a good chance you could talk me into doing it sans intercooler.

Thanks
ryan

 

Good questions...

Dunno how much it helps you (or what the intake temps were) but the above setup in the pic I attached ran 12-13psi on the stock S4 turbo (ie. nearly a f***ing blowdryer at that boost level ) and had a single 550cc equivalent nozzle...

And depending on what type of injectant you're using (meaning if you're using water or a mix with water) I presume you'll be limited to the point at which your intake air stream will become saturated...........?

 

talk to riceracing. He's doing lots of stuff with preturbo water injection.

 

I PM'd him a while back but haven't gotten a response....

 

check out his differant threads. you should beable to get some info from there. To be honest rotarygod is the first person I heard say that water can't hurt a compressor. I've never heard that before. Interesting though.

 

In the link I posted they say that also. The key is atomization.....they use this example and I think its perfect.

Ride your motor cycle in a rain storm, the big droplets sting like hell, but drive through a mist around a lake on an early morning and it just makes your skin wet. And there's the whole draw-through carb scenario also......

 

It's not to say that water CAN'T hurt the turbo. Blast a firehose at the turbo and see what happens! At the levels that will be injected to control detonation, it just won't hurt it. Think about how much water would be injected over an amount of time in the worst possible scenario. Compared to the amount of air and fuel entering the engine, it just isn't much. We know a carb can be run in front of a turbo and it would provide far more liquid through the turbo than AI would.

 

From my research into the pre-turbo injection question, my take is that the effect is a shift in the compressor map, which in effect makes the turbo have the abilities of a larger turbo. I think given that the injection would be at higher RPMS the chance of the water from the jet re-formulating into water after the turbo...which will vaporize it, is a small chance. The key to this would be a very small jet that is only activated at high RPMS and WOT. I would look at your compressor map for the turbo you are using and see where its effeciancy starts to fall off and then plan injection to keep the compressor map large where you need it. Keeping the injection window at this jet small and only for a brief time will yield results while also limiting possible turbo damage.

 

What do you want to know? Compressor map alternation is far from bunk, what is bunk is not running preturbo injection and having to run a big laggy compressor...

 

do a google search, you wont find many compressors that are for shure (dude) damaged by water injecton. you'll find a few maybe cases.

as long as you dont get stupid, it seems to be a moot issue

 

interesting, Makes me want to try it out but I think since I'm going to be using c16 then I won't do anything terribly crazy with my AI besides run 2xm10 injectors on the tb inlet.

 

I would think that if your turbo is considered small.....meaning that an upgraded turbo would yield significant results, then try pre-tubo injection before the upgrade. I think pre-turbo would really shine more on a car with a smaller turbo then on modified all out maximum effort car....on these cars its lag thats a problem not flow in the upper RPMS or gears.

 

Interesting point on using the compressor map to select the injection point....

Does anyone have a map for a T04-R? Most sites such as ATP don't have maps for the T series stuff. Would a T04-Z map be "close enough" to gauge a decent starting point?

So I take it from this post that the change is going to occur or be most effective at the top of the turbo's range? Making a smaller compressor act larger correct? Not make a larger turbo spool faster?

What kind of jet sizing are the guys running this using, and I'm planning on running a water/alchol mix....but for discussion sake, what would be the benefits (or possible downsides) to using meth in this location? Similar to the benefits it has over water in general?

 

i used it on my elford turbo without an intercooler with the carb infront of the turbo, worked well. was really dependent on jet size though i had to use a really small jet like one gph other wise the turbo struggled to spool. went like stink.

i used it up to 16psi were i moved off the compressor map. it was with a T3 turbo.

but well worth a try.

Ollie

 

I have not tried pre-turbo to prove it to myself yet. But before I went to an upgraded turbo I was did some preliminary research into pre-turbo injection. Points that everyone seems to agree on are very small jet, jet located very close and pointing directly at the nut on the compressor wheel, high pressure behind the jet. I think after reading its the chemical reaction of the water being injected/compressed at the turbine is what is wanted, the chemical reaction is what in effect alters the compressor map. If the compressor map matches the engine operating parameters at a lower RPM and then falls off later on......usually this would be because of a smaller turbo, then in my mind what would be effective is to keep this turbo and use its map where it works well and then when it runs out of steam, inject water to bring the map back into the sweet spot. On a bigger turbo I do not think that altering the compressor map will help unless the engine can benefit from the change, usually with the larger turbos you have got the top end already and its on the short side down low where the sacrifice has been made hence nitrous being used to get it spooled up.

Now it comes down to what parameters to use for triggering this pre-turbo jet and for how long. IMO it would be WOT, RPM, and MAP.

On my car with the original factory turbo, near the end of the track it would seem that the pull was dying off.....it might be that gearing at this point as well as load plus the size of the turbo all help to contribute to this. Maybe it might be also wise to have a 4th or 5th gear switch added in.....not sure though.

I will possibly revisiting pre-turbo in a couple of months.....but right now for me its all talk.

 

Benefits being initial impact being against the durable (more so then the blades that is) nut? As well as the water being able to efficetively sweep across the entire blade, cooling the blade and air charge the whole way?

Am I following correctly?

What car/turbo?

On a T3 you said correct? Any lbs/min figures on the turbo? As well, the 1gph nozzle, what kind of pressure (or even better, which kit/system?) were you using? and were you using water? water/alky?meth?

 

it was a 12a turbo first gen.
i havent got the info on the trim of the turbo to hand.
it was a coolingmist varicool thing with elegedly 100psi pump (cant confirm)
i used the o.75m jet with water which gave the best cooling and 50/50 with 1 gph
and 3gph of methanol which in my situation made most power. the car didnt like any more water than 1gph but that might have been my ignition ( second gen coil)

i fogged the aux injection in the sock filter of my velocity stack on my carby which was before the turbo.

Ollie

 

search is your friend

Many years ago I posted a dyno sheet of 472rwhp (dynapack) on a H trim compressor wheel @ 19.9psi boost on street port. H trim is from memory a 57~58mm minor diameter.

This is with my own pre turbo WI system
That exact same set up made 435+rwhp for 2500rpm on a dyno dynamics system on a stock block 13B..... running for many years.

Pre turbo works fantasticaly well.
A mate of mine here uses it on his car and makes 578rwhp (dyno dynamics system) on 21psi boost ! on 72mm compressor (T51) on pump fuel alone and the power band is absolutley insane !!! you can leave the car in 4th gear and accelerate and at 5k rpm it is all over the road and totaly out of control.

My experience of pre turbo WI is that it indeed does help turbos maps and lets you use a smaller turbo and get great responce, i dont run any turbo rotaries without it personaly

 

hey rice what do you think about what they are saying about not needing any special atomizer, that water doesn't hurt a compressor wheel?

 

rubbish

it will **** the compressor real quick if not atomized to proper size.

on a draw through carburettor system it may be ok, as many here 10 to 15 years ago ran simple dribble water injection systems but on any modern pre turbo set up I can tell you it will damage the leading edges of the compressor wheel if not properly atomized prior to hitting the compressor.

my jets/atomizers go to around 5 micron and dont start injecting untill there is sufficient flow of air to ensure best operation, the other tip I can give you is after a decade of doing this on a number of instilations that I would strongly suggest filtering your water with a mineral filter as is bought in a supermarket to make you own *clean* water at home. It takes 10's of thousands and many hundreds of litres of water use but there is benifits in doing this too.

 

Peter,

I have searched all of your threads concerning pre turbo WI; and I have gathered some of the data, however I honestly don't know where to start, or how to piece everything together.

I have invested so much time and sweat on my FC, that I am afraid to try (or piece together) things that I don't understand. I am VERY interested in your WI setup\kit; could I just buy one from you?

I am very close to completing my FC, and would like to start with pre turbo WI right out of the bat

Could you hook me up? Pppppppplease!

 

Thanks for the info!

Thanks for the info also! I have searched your threads as I believe I mentioned in the PM but I'm still a little foggy on a few aspects.

One being I don't plan on exactly "betting my engine" in tuning...my mind might change on that later but losing a 400km rebuild driving down the road in vac has left a bad taste in my mouth...would there still be benefits to be had with pre-turbo injection while bearing in mind the car will be on a relavtiely conservative tune?

More simply put, will the setup provide benefits even if I'm not tuned to detonate without the WI?

On a personal question, do you run straight water? or water and denatured alcohol? If so at what mixture?

Another question would be if these setups have intercoolers? I have one in my setup, is there something I should be planning ahead for like a petcock to drain out water? Will water actually even fill my intercooler at a "moderate" spray level?

I'm sure theres more....but I think its a worthwhile discussion.

Thanks again for sharing!!