AEM Water/Meth injection pre, post turbo(s) or both?

[Valhalla]

So I can qualify as much information as possible (I know there is going to be some questions) I will lay out my system and concerns.

• 1997 NSX-T 3.2
• AEM Series II stand alone EMS
• AEM wide band UEGO O2 sniffers
• Twin Areodyne 55 series variable vane turbos with single port adjusters and blow off valve
• Corky Bell cold side intake with ATA intercoolers behind the rear tires (one per side)

So what is the issue? Once I get above 6k the little ATA intercoolers can not keep up, my IAT's climb and so my timing gets pulled by the AEM. I'm good with that as that is what the Series II reads and does on it's own. My built in security blanket. But my EGT's are 1300 at 3k and i'm just concerned with longetivity and keeping the ringlands intact.

I've followed with keen interest the research done by RYU and LMR with their water only setups on their Comptech Superchargers and have recently purchased one. But before install, I need some thoughts on install because I have found different lines of thought on placements. So here goes with the questions;

• I have the one gallon resevoir with the fail safe, low level indicator and trip if I do run out of fluid.
• I would like to mount this under the front hood where the spare tire used to live. Any issues with this remote location? I need the trunk space as my wife packs lots of shoes!
• I know this can be wired up off the EMS to flow juice at whatever desired rpm/boost I want. I'm thinking of 2psi or setting it off IAT, independent. Thoughts?
• Now here is where it gets crazy, I've researched where some folks suggest adding the water/meth pre-turbo(s) at the inlet to cool the charged air at the source of it getting hot. Some say "stay away" and add pre throttle body. I've even read where some say you can add pre turbo and a secondary driver can add more pre throttle body as needed!
• I'd like to stay with water only but my tuner suggests going 50/50 as I won't have to worry about a hazard with going with straight meth and the added cooling feature. I'd like to stay with water only. Thoughts here?

So what do you think?

 

[RYU]

Are you doing 50/50 meth/water or just water?

 

[Valhalla]

Sorry Regan, was updating the thread when you were posting. I'd like to stay H2O only but will entertain everyone's thoughts.

 

[doc_tai]

From my understanding pre turbo water injection is for when try to get a little more out of turbo. It can damage the turbo compression wheel if some clog the jet and not spray fine mist instead of water drop

 

[RYU]

This is just my opinion. I have not studied the Aerodyne turbos at all.

I would do it post turbine, pre TB. This way none of the Aerodyne vanes, turbine, seals, bearings get exposed to any additional moisture than what's in the humidity from atmospheric conditions (rain, fog, mist, etc). I can see some benefit in cooling the turbine and turbine housing itself if you're really trying to squeeze out every ounce of performance but for longevity sake, i'd argue not spraying even 100% water pre turbine.

With that said, I certainly would not spray any meth mixture pre-turbine. It might be fine for the short term but its not worth decreasing the life of the turbines thru potential corrosion. If I was spraying 50/50 meth/water (which i'm not a fan of for mildly boosted engines) i'd definitely do it pre TB or even try for post TB.

Again, not an expert. Happy to be proven wrong. Just applying some basic logic in my arguments.

 

[Valhalla]

I respect your opinions. The thought and reasoning behind pre turbo is you get even greater atomization and also cooling the charge air more effectively at the point where it normally gets hot, under pressure. Of course the down side is potentially damaging the turbine, seals and bearings and of course the condensation in the ATA intercoolers. As with everything in life, a compromise.

So if I decide to spray post turbos, do I opt for the juction to the TB or do I add the injector post ATA intercoolers, two feet upstream of the TB? Would I gain better IAT's at this location or would the atomization fall out of suspension that far away from the intake manifold?

 

[RYU]

I respect your opinions. The thought and reasoning behind pre turbo is you get even greater atomization and also cooling the charge air more effectively at the point where it normally gets hot, under pressure. Of course the down side is potentially damaging the turbine, seals and bearings and of course the condensation in the ATA intercoolers. As with everything in life, a compromise.

So if I decide to spray post turbos, do I opt for the juction to the TB or do I add the injector post ATA intercoolers, two feet upstream of the TB? Would I gain better IAT's at this location or would the atomization fall out of suspension that far away from the intake manifold?

Yes, it's always a compromise unfortunately.

I do hope other people chime in and it's not just me here.

Theoritically damp air will allow for better heat transfer in your IC. Therefore it should make your ICs mildly more efficient. I'd do it post turbine, pre intercoolers. Intercoolers are cheap. You can replace them easily. Turbos.. not so much.

 

[E-Nough Logic]

What are your IAT's reaching and what is the ambient temps?

I guess right off the bat my first instinct is to ask why not fix your intercooling problem. The water/meth is a bandaid for your issue. Others don't have options available to them, supercharger owners particularly, but you do. If a turbocharger system is designed properly and sized properly the only reason, arguably, to run water/meth is to exceed the limitations of the gasoline they are using.

How much boost, and how much power are you making? Would like to see a picture of the layout as well just for my own knowledge of that particular system, I haven't seen it before, but heard of it.

As far as the water injection, my opinion would be post intercooler and pre throttle body. Reasons are two fold, one you would need two injectors for the dual intercooler system vs just the one if you put it right when they combine(Maybe 2 is better anyway for atomization, not sure). Second reason is that if the water doesn't atomize adequately before the intercooler it may not be as effective.

 

[peiserg]

I've done thisnin the past. Seems post intercooler is best option. That way you have lowest possible intake temp. If you spray pre intercooler, and your intake temps drop to say 75f, but your intercooler is 80f, your intercooler will actually warm the intake temps. If your.intercooler is 80f or whatever temp, it's still unlikely to be as cold as a meth.spray... so you will have a temp drop across the intercooler, and yet again from the meth.

 

[Valhalla]

Thanks for chiming in guys. Much appreciated. The intercoolers are not doing the job and to try and plumb in the usual WTA intercooler, there is no room because that is where one of the turbos is sitting. The other more expensive option is to get on the IM WTA intercooler that Dave Dozier is creating but for a lot more money and I don't think he has finished up on the research, let alone availability and pricing of that system.

Ambient temperature difference is +100F when I am running high rpm's and the little ATA's are cooking hot. I'm running at 8psi and because the IAT's get so high, the EMS is retarding timing. I know the water injection is a band-aid of sorts but trying to make things a little safer and longer lasting.

Here is an article on the system I am running. Not exact but pretty similar. http://www.nsxprime.com/forum/showt...ger-Twin-Turbo-Kit?highlight=corky+bell+turbo

 

[E-Nough Logic]

100+ degree temp difference is huge yes, realistically I get 30degree +/- difference usually, and it doesn't budge under boost, it is usually at it's worst when the car is heat soaked after sitting for a bit and getting back in. I'm running a 1000hp Garrett core intercooler right next to the throttle body where the stock airbox used to be, without any issues. My charge piping comes from the wheel well though, as opposed to your setup which comes up from the transmission side. Something like that might work for you though.

 

[RYU]

Knowing how hot my under "hood" temps get I have no idea how any ATA intercooler actually works in our cars. It's part of the reason I have not gone turbo myself (outside of other bigger reasons like CARB). I agree with folks here saying that your ATA intercooler is probably heatsoaking. You might actually be better off taking out that intercooler, wrapping your charge pipes in thermal wrap or gold shield and spraying 100% water like I do in my CTSC... Just a thought. Also, I think you have your intercoolers towards the rear of your fender wheel well. That's is typically a high pressure area. Not sure how well the air flow is going thru your cores there. Perhaps a WTA setup would work better? Just trying to help you brainstorm amigo. I really enjoyed riding in your car last time. Sad to have a heatsoak problem dull that feeling!

BTW...the biggest problem I have is that i'm running too cool with the water spray. I averaged 36C IATs at the track last month and i'm already running the 2nd to the smallest nozzle I can find. This is pre-blower too.

- - - Updated - - -

It would really be interesting to provide some IAT data in your setup pre-IC and post-IC. That would tell us volumes.

 

[E-Nough Logic]

Knowing how hot my under "hood" temps get I have no idea how any ATA intercooler actually works in our cars. It's part of the reason I have not gone turbo myself (outside of other bigger reasons like CARB). I agree with folks here saying that your ATA intercooler is probably heatsoaking. You might actually be better off taking out that intercooler, wrapping your charge pipes in thermal wrap or gold shield and spraying 100% water like I do in my CTSC... Just a thought. Also, I think you have your intercoolers towards the rear of your fender wheel well. That's is typically a high pressure area. Not sure how well the air flow is going thru your cores there. Perhaps a WTA setup would work better? Just trying to help you brainstorm amigo. I really enjoyed riding in your car last time. Sad to have a heatsoak problem dull that feeling!

BTW...the biggest problem I have is that i'm running too cool with the water spray. I averaged 36C IATs at the track last month and i'm already running the 2nd to the smallest nozzle I can find. This is pre-blower too.

- - - Updated - - -

It would really be interesting to provide some IAT data in your setup pre-IC and post-IC. That would tell us volumes.

Honestly they don't. IF there is some proper routing of air it's possible, but most just throw it somewhere and hope air gets to it. Now usually this hasn't been a problem because many have run relatively large turbochargers for their power goals. Now when you take a smaller turbo, or pair of smaller turbochargers that really have to fight to feed the NSX engine at these boost levels then demand for cooling increases. I don't know the exact specs on the Aerodyno chargers, but I believe the original kit cam with the 128's please correct me if I'm wrong, and I'll come up with another compressor map.

The Black line represents the airflow demands of the NSX engine between 3000rpm, and 8000rpm assuming it can make 400whp at 8psi. Realistically the NSX engine can make a lot more power at these boost levels than they originally thought when they designed this kit. At 8psi the NSX can efficiently make 450whp, but lets shoot short, and say only 400whp. With a 15% driveline loss lets stick with 475hp. This requires roughly 47lb per minute of air which = 340cfm per turbocharger on the aero dyno kit. This is just a real quick assessment, but should be in the ballpark. As you can see the turbo is pushed way past it's efficiency. The red vertical line represents the point at which a normal Garrett compressor map would stop, which is usually around 65% although this map goes all the way to 55% very inefficient. Realistically these turbos are only healthy to produce 190hp a piece, or 380hp when paired so roughly 325whp. Now some may say, well I only want 325whp from my NSX, well it doesn't work that way, the turbo must meet the airflow demands of the engine AND do it at the boost levels the engine will want.

The green line represents how much my engine demanded at 8psi which was almost 450whp, and is not uncommon.
http://www.nsxprime.com/forum/showt...sizing-and-recommendations-for-a-unopened-3-0

 

[stuntman]

So your AITs are a little under 200*F?

Pics of your IC setup and where they get air from?

Can always spray the IC itself

 

[Valhalla]

The intercoolers are small, about 12"x12" and sit directly behind the rear wheels. They are tucked up to be flush with the bottom of the fender. They are not pushed back toward the rear valence at all. E-Nough-Logic, that looks like the right compressor map but I would have to double check. There is boost and then there is cubic feet per minute. I understand that. Little turbos can spin a lot of boost but are restricted by the amount of air they can push. Maybe I should mount small fans on the intercoolers to either push or pull air through them?
View attachment 110808

 

[E-Nough Logic]

Maybe DDozier can comment on what he has seen using these. I believe he tracks his kit I wonder what iat he sees, power levels etc. i know he uses the larger ones though.

You shouldn't have to fight so hard to keep cool at such low power levels. Any chance you have e85 available over there?

 

[stuntman]

Pics of the intercoolers mounted? Fans would help.

 

[RYU]

I know you're trying to do as little as possible so here are my ideas if this was my car and without spending a lot of money doing so. Just your time...

I'd place a few "streamers" in the front and behind the intercooler. I'd grab my gopro and film how the air flow behaves around both areas. If the air is stagnant (I suspect it is) then fans will certainly help. If there IS airflow around the area then it gets a little more confusing. Fans may help at slow speeds but may be a hindrance at high speed. At what speed it becomes a hindrance completely depends on the air flow characteristics already there.

Take a look at illWillem's build thread. He did some ducting to his oil cooler (which is located in roughly the same spot) that takes high pressure air (forced in thru the side ducts) and flows it thru low pressure air created behind the oil cooler from behind the car. I believe it is working for him but we won't know for sure until it gets really hot in the summer I reckon.

 

[Valhalla]

E-Nough-Logic - Dave Dozier does track his car and he also has the large frame Aerodyne's. But he has also created an ATW intercooler plate that replaces the VVIS plate and is able to keep his IAT's under 120F while tracking! A very nice piece but it appears to be a "one-off" system. He uses a system similar to the SOS cooler before the radiator and runs the hoses thru the tunnel and up to his IM intercooler plate.

Billy - I will take a picture of my intercoolers and their location and post up soon so you can see what I have to work with. They are not big.

Regan - I agree with airflow, or potentially lack there of. That is why when I wrote of possibly mounting fans on the intercoolers, it may depend on if i need the fans to push or pull air through. Dependent upon what ever airflow I am currently getting.

 

[kookoo4nsx]

Are these little turbos working too hard at 8psi? The article link showed initial boost levels at 4.5psi and about 305 whp.
I know this is what you won't want to hear but perhaps consider dialing the boost back to 5psi max and run it for a week
and check your average temps.

 

[Valhalla]

With the stock springs that come with this turbo, 7.5 is the max they produce. You can shim the stock spring and that gets you .5psi with every added shim. Aerodyne sent me the next two sizes of springs without me asking. We tried the bigger springs but all we got was more heat and no more wind. So we went back to the bare stock setup. I have a Zietronix gauge display with audible warning and I have that set for 7500 rpms and any boost over 7.5. It occasional goes off for over boost but I am within Aerodynes' recommendations. And I am way over the 305 rwhp in the article. I'm just trying to make the engine safer. If I gain a few more ponies, cool. But I don't want to be driving a grenade. The motor has already been apart, twice. Can't afford a third time. Thanks for the thoughts.

 

[DDozier]

So here goes with the questions;

• I have the one gallon resevoir with the fail safe, low level indicator and trip if I do run out of fluid.
• I would like to mount this under the front hood where the spare tire used to live. Any issues with this remote location? I need the trunk space as my wife packs lots of shoes!
• I know this can be wired up off the EMS to flow juice at whatever desired rpm/boost I want. I'm thinking of 2psi or setting it off IAT, independent. Thoughts?
• Now here is where it gets crazy, I've researched where some folks suggest adding the water/meth pre-turbo(s) at the inlet to cool the charged air at the source of it getting hot. Some say "stay away" and add pre throttle body. I've even read where some say you can add pre turbo and a secondary driver can add more pre throttle body as needed!
• I'd like to stay with water only but my tuner suggests going 50/50 as I won't have to worry about a hazard with going with straight meth and the added cooling feature. I'd like to stay with water only. Thoughts here?

So what do you think?

I would find a location for your tank in the rear of the car somewhere, if you look around you can find a 1 gallon tank that will fit in the fender after you get rid of the ATA coolers, You can fill from a remote filler neck in the engine compartment and run a hose to the resevoir in the fender location. You do know that this will not be an issue as soon as I get off my butt and build you a proper intercooler, (you are on the short list to get one).

I know you will not need the meth after the intercooler is installed but it will not hurt to keep it and you will make a few more ponies with the 50/50 mix. Spray at the TB, not before the turbos, the compressor map listed above shows numbers next to the pressure waves on the map, those are the impeller RPMs. I know others have done it but I cannot imagine it being good for any metal part moving at 100,000 RPM to hit anything other than air, but YMMV. Set the ECU to trigger the pump on and off at 2PSI, do not worry about refferencing IAT's as it really does not matter if you are in boost you are making heat. You want maximum cooling all the time why wait for the problem before the solution. You will not need to spray much so a single smaller nozzle will work fine.

Dave

 

[Valhalla]

Thanks for chiming in Dave. I was hoping you would. I'll wait patiently for you to start up production. I know others are looking for your setup too. Now get to work!

 

[Valhalla]

Back from the dead. I'm finally getting around to installing this post ATA intercoolers at the throttle body. Will mount the bottle and pump up front and have that all mapped out. My question is how to mount the nozzle at the throttle body coupler? Here is a picture of the junction.
View attachment 114575

Here is a shot of another Corky Bell system with additional injectors added to the same coupler
View attachment 114576

And here is a picture of a similar Bell twin turbo system. Notice the placement of the ATA intercoolers directly behind the rear tires.
View attachment 114577
As you can see there are two sites to add injectors but these are open bungs, with no threads, of about 10-12 mm. It's cast aluminum so I'm wondering if I can get this tapped and have an AN fitting installed to thread the injector nozzle into? If so, any recommendations in south OC? Thanks guys, you are the best.

 

[RYU]

Im' curious why you decided to put the nozzles post intercooler. I've never studied this but my small brain tells me the heat transfer from the intercoolers can be optimized if you spray before them. Perhaps you're concerned with low air flow to the intercoolers? If that's the case, I might consider getting rid of them and going full spray. Again, I don't know.. just posting some options.