Dyno results and subsequent thoughts-Pics and Vid up

[Turbineguy]

I was in Arlington TX a few weeks ago and while there I took a saturday trip to Cobb Tuning (yes THE Cobb Tuning) to check out the new shop and maybe get some baseline pulls on the dyno. A little prior info on the current state of tune. I had been running around 23psi lately but had turned it down to about 20.5 because I was messing with running less boost and more timing to see what worked better as well as it being stupid hot here. Dual nozzle setup on the water/meth injection with one in the normal place after the IC before the throttle body and another injecting pre turbo. I had also pulled the intake manifold, TB, TGV housings and turbo out about 2 months ago to do a full port match, polish and gasket match along with completing the full TGV delete and adding in the braided AVCS/turbo oil feed line setup. Cobb uses a Mustang dyno which tends to read a little lower than other types but more consistent (which is what I really care about). Temp inside the dyno room was 104 with humidity around 30%.

So at 20.5psi it put down 340whp and 360ft/lbs which is pretty consistent with what to expect on a little 18g. I can safely run 28psi through this turbo but keep it under 23.5 due to limitations of the stock MAP sensor. 23psi would net around ~360 or so at the wheels on the same dyno with about 380ft/lbs.

Thoughts and observations after the fact. I've been working on refining the current tune for almost a year. It shows on the dyno plots. Nice and smooth curves for HP, TQ and boost. AFRs transition smoothly from closed loop into open loop and stay flat at 11.2 with no fluctuation at all. Full boost at 3200rpm and table flat until the hotside chokes and then tapers smoothly to the redline. The point of all this is some encouragement for those who are new to tuning and may feel a little lost or intimidated by it. It takes time, patients, experience and alot of good knowledge to get it right in the end but it can be done. I've been at it for years now with many different cars but this one has been the biggest challenge so far. Next up is a change in tuning software in a week or two and right after that a new turbo (Blouch Dominator 1.0) thats noticably bigger than the current 18g. The new snail should net comfortably over 400whp (I'd guess ~420) at about 21psi or so and my current mods. Thats about as far as I'll push the stock internals at this point since I'm still running the stock cast pistons which are prone to ringland failure. I'll have to build a completely new map with the new software for the new turbo and plan to keep this thread updated. I had planned on doing an air to water intercooler setup but I've pushed that back for a little while until I get the rest of the other stuff done. The AWIC will require some fabrication and down time which is the reason for the hold. More to follow.

[Dzaster]

Encouraging indeed. I am trying to work out some stuff as well and am losing much sleep over it.

Anyways, I have read up on water meth nozzle placement and have seen some mix statements about having it placed preturbo. Your take? And how do you have it setup to inject--both at same time or one then the other? What kit you running?

[Turbineguy]

...Anyways, I have read up on water meth nozzle placement and have seen some mix statements about having it placed preturbo. Your take? And how do you have it setup to inject--both at same time or one then the other? What kit you running?

Preturbo is definitely a debated idea. However it just takes a thorough understanding of whats happening in the physics world relating to the thermodynamics and other associated stuff to realize that it can net very good results if done properly. There are a few people who have refined their setup enough to be able to remove the intercooler completely due to the preturbo injection and it's affects on charge temps. If done properly the turbo outlet temps can be reduced below what an intercooler can do and it then becomes an interwarmer and therefore useless. It has the effect of shifting the compressor efficiency map to the right and make a smaller turbo perform like a larger one but with the spool of a smaller snail. This is caused by removing heat from the intake charge prior to entering the compressor. A much denser, colder charge is the result and since the thermal rise from compression is constant based on compressor efficiency the outlet temps are reduced by the same amount. Air temps going into the compressor can be well below ambient and some have seen as much as a 50 degree drop preturbo. If it's 100 degrees ambient and you would normally see outlet temps of 160 and then you factor in a 40 degree drop from the preturbo injection you end up with 110 degree outlet temps just 10 degrees over ambient. It is possible to to reach an adiabatic state but very difficult, time comsuming and expensive mostly due to the required thermal data equipment. The other thing that happens is that with a denser charge entering the compressor the turbo doesn't have to turn as fast to make a given amount of boost so it has a positive affect on spool and how soon target boost is reached.

I use an Aquamist 2D system in the Suby. I have one nozzle in the normal location just prior to the throttle body and another one just downstream of the MAF sensor. The biggest issue people have with preturbo injection is compressor errosion. The upper limit on droplet size is about 50 microns and obviously the smaller the better. The problem is that there are no injection systems on the market for cars that use pumps of high enough pressure to do this on a standard orifice type nozzle. It typically takes about 500psi and a nozzle with an air jet through it to atomize small enough. The solution is to place the nozzle right in front of the compressor wheel pointing straight at the compressor nut which directs the spray to the inner portion of the vanes which have a much lower radial velocity than the vane tips but still allows the vanes to finish the atomization through mechanical shear forces. The problem is how to mount the nozzle in that location and also how to feed the line to the nozzle. There are some rings available that mount there but they're very hard to find and pretty expensive when found. Another method which I use is to mount the nozzle well upstream at a right angle to the airflow path. This allows much more time for vaporization and the right angle creates a strong shear force at the nozzle face to also help atomize. I haven't seen any real issues with errosion on my compressor so far. I've run a preturbo nozzle for almost a year and just had the turbo out about two months ago and it looked fine. Both nozzles come on at the same time. The line comes from the pump to the high speed valve and from there it has a Y connector going to both nozzles.

There is another part to the debate which is whether to run methanol, water or a mixture of the two. Again it's an understanding of the physics which is all thats required to settle it in my opinion. Daltons law of partial pressure basically says that air can only absorb so much water until 100% saturation but the air also has a 100% saturation rate for methanol as well. The two are mutually exclusive and you can saturate the air to 100% of it's capacity for water and also saturate it to 100% of its capacity for methanol at the same time. You therefore get the heat absorbtion capacity of the water as it vaporizes as well as the same for the methanol. The methanol also has the added benefit of adding back in a cool burning combustable fluid which helps to make up for fuel displaced by non combustable water.

T

[Dzaster]

Awesome response TG!

So both at the same time. So when you say you place the pre turbo nozzle "well upstream" how many inches/feet are we talking from the compressor inlet?

Also, in regards for tuning AFR, do you pretty much tune for the same AFR when it kicks in and when exactly to you have it kick in on your 20.5psi boost range?

Also do you have a failsafe and are tuning ignition timing based on meth/water injection?

Sorry if this isn't the path you wanted to go with this thread, but its just that I've not really been able to converse personally with anyone about a meth injection kit so that is why I am picking your brain about this. I don't know anyone, PERSONALLY, running it--besides you. Therefore, my understanding is solely based on the plethora of discussions on the net--and I do mean "plethora". lol. I read through as much as I could, took the most common method/process and went with that. Seems to be working fine for me, but I use it more as a safety buffer for the not so great 92 octane gas we have here.

[Turbineguy]

Awesome response TG!

So both at the same time. So when you say you place the pre turbo nozzle "well upstream" how many inches/feet are we talking from the compressor inlet?

Also, in regards for tuning AFR, do you pretty much tune for the same AFR when it kicks in and when exactly to you have it kick in on your 20.5psi boost range?

Also do you have a failsafe and are tuning ignition timing based on meth/water injection?

Sorry if this isn't the path you wanted to go with this thread, but its just that I've not really been able to converse personally with anyone about a meth injection kit so that is why I am picking your brain about this. I don't know anyone, PERSONALLY, running it--besides you. Therefore, my understanding is solely based on the plethora of discussions on the net--and I do mean "plethora". lol. I read through as much as I could, took the most common method/process and went with that. Seems to be working fine for me, but I use it more as a safety buffer for the not so great 92 octane gas we have here.

No issues with questions like these. They all pertain.

Well upstream for my setup is about 17" or so. Is it optimal? Probably not but it works well enough to experiment with.

The best way to tune AFRs is with Lambda rather than the normal ratio everyone is used to. Lambda is based on a scale where 1.0 is stoic and less than one is rich and more than one is lean. This method works well on a multifuel setup since stoic for gasoline and stoic for methanol are far from the same. It reads residual o2 in the exhaust stream regardless of the fuel and you get the same number based strictly on the o2 and not a fuel specific ratio. Now to answer your question I don't use the Lambda method because the shop tuners don't either and neither do the other tuners on all the forums. I shoot for my target sans meth, adjust my meth flow and then start pulling fuel until I get back to my target. Right now I'm running 11.2 straight across the rev range under boost. The water/meth comes on at 8psi. The Aquamist 2d is a variable flow system based on fuel injector pulse width and gets it's signal from a tap into the #1 cylinder injector signal wire. I actually have no traditional failsafe built in to the system. My failsafe is in the tune. I allow the ECU to advance timing over the baseline table value and if there were a failure the ECU has enough authority over timing advance that it can retard the timing far enough to prevent detonation. Some people tune close enough to the edge of safety that they excede the ECUs ability to protect the engine. My method may sound a little risky but I've intentionally shut off my meth system before and run the same map under full load to see what kind of margin I have. No issues.

[maxgtr2000]

I am bowing down to that knowledge. Pics and dyno videos please.

[Dzaster]

How much psi is your pump that it flows the two nozzles and also what is the rating of the nozzles. Just thinking that I might end up giving it a whirl--pre and post turbo nozzles. I like the thought of having the turbos run like a larger yet spool like a small guy.:D

I understand the lambda deal some. Perhaps I should be shoooting for a little richer AFR. And with the failsafe in regards to timing, that is pretty much exactly what I was curious about--whether or not you were tuning to a significant timing advance on the meth/water. Man, I'm kinda weak that my ECU can't alter timing based on knock. Oh well, perhaps someday.

[Turbineguy]

How much psi is your pump that it flows the two nozzles and also what is the rating of the nozzles. Just thinking that I might end up giving it a whirl--pre and post turbo nozzles. I like the thought of having the turbos run like a larger yet spool like a small guy.:D

I understand the lambda deal some. Perhaps I should be shoooting for a little richer AFR. And with the failsafe in regards to timing, that is pretty much exactly what I was curious about--whether or not you were tuning to a significant timing advance on the meth/water. Man, I'm kinda weak that my ECU can't alter timing based on knock. Oh well, perhaps someday.

I have the older style magnetic pump which run at 100psi. The newer systems from Aquamist use a larger SurFlo pump that runs at 150psi. I tried to wire in one of the newer pumps but the electronics and internal relays are all different and I'm unsmart on some of that stuff. Aquamist told me it can't be made to work anyway even though there are some people who have done it but I'm sticking with the current one I'm using. My nozzles are measured by the size of the oriface in mm and not flow rate since that can vary with pressure but there is a conversion chart on the Aquamist forum. It's been a while since I looked at it and can't remember what my total flow is but the requirement is a little different when you run preturbo injection. The Aquamist forum has a large thread on the preturbo stuff with alot of pointy headed labcoat type smart people that know alot more than I do about it.

My ECU is still the OEM one. Most new factory ECUs have a learning capacity and are able to do the same as mine. Pics and dyno vid as soon as I can get em uploaded.

[Turbineguy]

Dyno Vid

http://i419.photobucket.com/albums/pp280/Turbineguy_2008/th_P1010322.jpg (http://s419.photobucket.com/albums/pp280/Turbineguy_2008/?action=view&current=P1010322.flv)

Dyno Plot

http://i419.photobucket.com/albums/pp280/Turbineguy_2008/DynoPlot.jpg

Pic

http://i419.photobucket.com/albums/pp280/Turbineguy_2008/P1010319.jpg

[Dzaster]

Nice. So did you have them do any tuning or was that visit simply to for a run on teh dyno to see where things were?

I have found the only dyno on my island and am seriously considering. Actually, I'm currently making the move to get out there--fund raising.:rolleyes:

[Turbineguy]

Nice. So did you have them do any tuning or was that visit simply to for a run on teh dyno to see where things were?

I have found the only dyno on my island and am seriously considering. Actually, I'm currently making the move to get out there--fund raising.:rolleyes:

No tuning. Just there for baseline runs. Calvin did give me a few pointers though and did nine pulls rather than the usual three that you get for baselines.

[Mrdb]

Pre turbo water/meth injection has a number of theoretical issues.

1) Water is abrasive so it will damage the vanes ( to what extent is unknown )

2) Water hitting the vanes will cause inbalance ( how much is again upto debate )

3) It will cause thermal stresses on the vanes due to rapid heating cooling.. (again unknown extent)

advantage is you do not need to produce as high a pressure to compensate for boost.

apart from that i can see no advantage but lots of theoretical disadvantages.

Although the problems so to speak could be so minimal it isnt worth worrying about but they are worth taking note of and taking your own risks...

[Turbineguy]

Pre turbo water/meth injection has a number of theoretical issues.

1) Water is abrasive so it will damage the vanes ( to what extent is unknown )

2) Water hitting the vanes will cause inbalance ( how much is again upto debate )

3) It will cause thermal stresses on the vanes due to rapid heating cooling.. (again unknown extent)

advantage is you do not need to produce as high a pressure to compensate for boost.

apart from that i can see no advantage but lots of theoretical disadvantages.

Although the problems so to speak could be so minimal it isnt worth worrying about but they are worth taking note of and taking your own risks...

1. Water is not abrasive. If it was we would use it as a polishing compound. The issue is water droplets hitting the compressor when it's rotating at over 100k rpm which is why controlling droplet size is so important.

2. Do you honestly think the water stays attached to the compressor wheel in any kind if liquid state and at the normal shaft speed a turbo operates at? You do realize the flow through a turbo is supersonic right?

3. The compressor goes through significant thermal stress as is. Think about going from ambient or even subambient at low throttle to full boost with temps double ambient or more. Properly set up preturbo injection has the potential to reduce the thermal stress on the compressor by never allowing temps to rise as high within the compressor itself.

"advantage is you do not need to produce as high a pressure to compensate for boost."

Please explain this one. It makes no sense at all. Boost IS pressure-or rather restriction to flow but thats another thread all together.

I understand it's at my own risk. Thats why it's called experimenting. Sometimes it works and sometimes the lab blows up.

[Mrdb]

water ill wear anything out eventually, errosion coast lines etc...

anything hitting the vanes at sub / supersonic speeds will cause vibration.

water cools signifcantly more than air ( or why use it ?) the turbo is a high thermal stress area and dumping water mist will cause a quick cooling of the vane.

"advantage is you do not need to produce as high a pressure to compensate for boost." prob bad wording but

Boost pressure has an effect on misting pattern. A 100psi pump misting before the turbo will produce a mist at 100psi, after turbo it will mist at 100psi less turbo boost pressure. You could probably use a lower pressure pump to produce the same mist pattern pre turbo rather than after..

All the above however is probably irrelivant and will not cause any problems for along time should / if they occur...

[bluesnowgt]

here are some more pics for u tim. i thought u would like to save these. great vid. i miss seeing that beautiful engine by of yours =)