Pre-Turbo Meth Injection

[mb7050]

Post Intercooler Injection(3)

Post intercooler injection technically refers to injection anywhere after the intercooler. However, in this discussion we are specifically taking about post intercooler injection which takes place directly after the air-to-air intercooler on an application which has a considerably lengthy discharge tubes

Here the user has numerous locations and plenty of space available to inject after the intercooler. Often times users will believe by placing the nozzle further away from the intake of the engine, they will have better atomization, better charge cooling and ultimately better performance. In a case like the engine above, placing the nozzles directly after the intercoolers is not as desirable as placing them directly inches away front of the throttle body or carburetor, as this is excessively further away then needed.

While this will result in a well atomized, cool air charge entering into the intake manifold. Much of the water methanol injection would have already evaporated leaving little injection available for internal cylinder cooling, added detonation control and reduced EGT's. Additionally, In some case's the air charge can actually begin to heat back up due to excessively long discharge pipes being routed around hot radiator, turbocharger, hot pipes and exhaust.

Location of the mass air meter and IAT or ACT sensor location should always be considered. Never inject pre-mass air. Only in pre-turbocharger applications when done properly can one inject prior to the mass air.


Direct Port Injection

Direct port injection involves positioning a water/methanol injection nozzle in each intake port of the manifold. This allows for the use of several smaller injectors to be used in each intake port as opposed to one larger nozzle located upstream of the intake manifold servicing all the cylinders. Unfortunately, direct port injection generally requires the removal of the intake manifold to complete installation. Thus making for a considerably longer and more complex installation.

While this does offer the benefit of better atomization, more uniform and even distribution through out the cylinders. In addition to possibly better detonation control, cylinder cooling and reduced EGT's. It's generally not needed as other nozzle locations can be nearly just as effective requiring considerably less work and costs involved. Furthermore, one problem with running direct port injection is users are not likely to monitor differences in IAT's (intake air temperatures)

Port injection is more common on 4 cylinder engines as added cost's for additional nozzles and fittings is acceptable and removal of these type of intake manifold is generally much easier. In general, we do not recommend port injection as we have achieved excellent results using other less complicated and costly nozzle arrangements and locations.

Pre-Compressor Injection Precautions

Never place your water methanol injector before the mass air meter. The only time this may be allowed is with pre-compressor injection. When done properly, little or no fluid is exiting the compressor. Only a cooler denser, high humidity air charge with little or no actual fluid remaining in the air charge after the compressor.

When installing your water methanol injection system on a EFI vehicle, it's best to first determine where the IAT or ACT sensor is located before deciding on a nozzle locations. Often times we can position the nozzle before the factory IAT (intake air temperature) or ACT (air charge temperature) sensor location without having to relocate it. This allows us the ability to better use the IAT or ACT sensor for retuning the ECU for the addition of the water methanol injection system.

Unfortunately, many of our newer vehicles have now incorporated the IAT sensor in to the mass air meter. With most applications we can disable this IAT sensor in the mass air meter and install a new separate IAT sensor in a new desirable location.

http://www.alcoholinjectionsystems.c...icle_info.html

[thor'svr4]

All the above mentioned setups are after the maf sensor. The main topic Is about locating the nozzle between the the maf sensor and the turbo (right before the turbo).

sorry im so used to running a blow through setup that i forgot the stock maf was draw through and before the turbo. my bad.

[TT Eric]

Not something I would ever do, but a good conversation starter. It seems that spraying 100% meth about 1" from the compressor yields the "safest" results. Nozzle has to be aimed directly at the nut, with a .75 or .1 GPH nozzle. Don't get it wrong or else...

I'm more interested in post turbo spraying, say a couple inches away from the outlet on both turbos. Hopefully giving the liquid time to atomize before it gets to the intercooler, preventing the liquid from pooling. In theory.

You probably mean .75 to 1.0 GPH I guess ?

Eric

[TT Eric]

i can see where the benefit would be, but for a DIY person, i think its a terrible idea unless you just have lots of time, money, and knowledge on the subject. interesting that its so widely used though.

on a dif note, i always thought meth injection was more desired to keep the pistons cool. you would not get that from pre turbo injection. making more boost is easy, keeping pistons cooler is not so easy

Yeah I would go staggered, not just pre-compressor.

Eric

[mehrshadvr4]

i'm thinking since methanol has tendency to absorb heat , it also would help to drop the charge pipe temperature even more after the air going through IC.

[mb7050]

I would start with a 1gph(63 ml/min) per turbo to be safe and then work my way up from there by adding more nozzles/ or a bigger nozzle. Just make sure it atomizes perfectly the droplet size is key to safe pre-turbo injection. People seem to have best results with 130ml/min - 175ml/min per turbo at 400chp or about 610cfm at compressor Inlet Conditions...

[mb3000]

You probably mean .75 to 1.0 GPH I guess ?

Eric

Yes that's what I meant. Sorry about that.

[mb7050]

Have a look on Aquamist uk forum, there is a 50 page post on it!.

this one ?
Injecting prior to turbo comp' impellers - waterinjection.info

[TT Eric]

I've looked into those jet holders and personally I would not bother with that, especially with small TD04's inlet, what a restriction it would make, plus we would need to find a way to introduce a line into the intake pipe to go to the holder...

About this picture :

I've talk with Rodney at AIS (alcohol injection systems), very very nice guy and he told me that this picture has been floating around the internet for sometime now. That impeller was not ran with any water methanol injection. Had it been using water methanol injection the impeller would be totally clean and not dirty. This damage was caused by not running an air filter in a really dirty environment...

I was asking him if they were selling .75GPH and he said that they do not offer nozzles this small, so I though maybe 1GPH... So I told him what I actually run (1000ml/min pre-throttle) and asked him what he would recommend me as pre-compressor nozzles, he said to not bother with 1GPH as it would do nothing, more like 4-5GPH (250-300ml/min) before each turbos... and this is additional to the 1000ml/min I'm already injecting before the TB. 1'' to 6'' before the turbos would be best.

Eric

[mb7050]

hmm interesting . I have noticed that most WI kits max out at 1600-1800cc(after that the line pressure is going to drop drastically) or so in that case you are very near the flow limits