New 16G Dyno Numbers on C16

[Black_Bullet]

No to go off topic but since compressor flow limits and getting more than expected power from a given turbo is being discussed this may be interesting to some.

There is evidence to suggest that pre-compressor water injection changes the compressor's flow characteristics making it in effect behave like a larger turbo. Here is a link for anyone interested in reading more:

Waterinjection :: View topic - Injecting prior to turbo comp' impellers

The thread is very long but has a lot of good info and data (some objective, some anecdotal). But in a nutshell, the pre-compressor injection seems to be able to increase the efficiency of the compressor and cause it to flow more air than the compressor map would otherwise predict. However, despite efforts to avoid it there continues to be problems with damage to (erosion of) the compressor blades.

Potentially, one could use this on a smaller turbo to retain it's desirable spool characteristics while getting the airflow potential of a slightly larger turbo.

I'm not implying that the TPG guys are using this to get these big numbers but who knows (other than them ).

If it doesnt atomize correctly wouldnt the water hit the turbo kind of hard?
and doesnt the water take up space of airflow?

 

[dsm-onster]

No to go off topic but since compressor flow limits and getting more than expected power from a given turbo is being discussed this may be interesting to some.

There is evidence to suggest that pre-compressor water injection changes the compressor's flow characteristics making it in effect behave like a larger turbo. Here is a link for anyone interested in reading more:

I've had success with pre-blower injection, too. It is a common thing to see alky injection before the roots blower. Though the meth can eat the surface of some screws and make it a neccesity to run it just to maintain normal efficiency.

 

[pboglio]

No. Garrett maps at 13.9 psi atmospheric.

 

[romeen]

If it doesnt atomize correctly wouldnt the water hit the turbo kind of hard?

Yes, this seems to be the primary problem with this form of WI. Attempts have been made to atomize the water as much as possible and even aiming the injection nozzle at different angles (at center of compressor, away from compressor, etc) but this continues to be a problem.

and doesnt the water take up space of airflow?

Without getting into too many details (some of which are above me) it seems that not a lot of water is necessary to get the desired results and the cooling of the air charge is so effective that below ambient intake air temperatures can be achieved. Because of this some believe that an intercooler should not be used if using pre-compressor injection as it may actually warm the air back up to ambient. So even though the water vapor does occupy some space, the nearly immediate cooling of the air charge and subsequent contraction of the air (making it denser) more than makes up for it.

If you have the time that thread on the Aquamist forums is quite informative and addresses these issues in detail. I hope I'm not doing it an injustice by paraphrasing and summarizing it. But again I wan't to keep this relative to the original topic and not go off on a detailed WI post.

 

[dsm-onster]

Chicago is 590ft above sea level. You're looking at only 14.4 psi atmospheric where you live . The best you can get is .5 psi.

romeen, that thread is an excellent read so far!

 

[pboglio]

Dsm-Onster

Ah damn, so true

On another note:

There is a certain air of arrogance among a few posters here that I find disturbing. There is no need to go insulting somebody man, not f**cking cool. They don't believe you fine. Show some class. Peace out.

 

[kraka]

As far as Short runner Intake manifolds helping compressor flow...

Which IM's are these? SMIM models, ie JMF, etc?

 

[rrussell]

I'm enjoying this thread.

I was wondering if anyone knew what the pro dsm guys are running for bsfc numbers on petrol.

The reason I'm asking is when I took the efi-101 class, Ben Strader mention some of the pro Honda turbo guys were running as low as .38 bsfc.

It was also mention that VP C16 helps to run a low bsfc number because of the higher btu's.

Thoughts...

 

[pickens]

You guys are not thinking about what it takes to run a compressor at 55% efficiency. Generally, speaking you end up not being able to spin the turbo fast enough (too little energy at the TW) to even get to that point. At 55% efficiency you are basically wasting half the energy of the TW by creating useless power robbing heat on the compressor side. That's why most compressor maps don't go that far down the efficiency range. The power it takes to spin the turbo faster is less than the power the TW can supply. So yes, a choke point of flow is only one part of the equation, the available turbine power is the "speed" limiter. Just because Turbo "A" can spin to 150krpms in a given housing doesn't mean turbo "B" can spin that fast either (that's where efficiency starts to come in).

Go ahead and try it if you'd like by sealing off your wastegate port and run the turbo as hard as you can.

 

[tstkl]

A well balanced blade can spin 10000000 rpms if enough energy is there, but like pickens said, you can't exceed the amount of energy the turbine wheel is able to supply. The amount of energy a turbine wheel is able to supply is determined by the volume, pressure, and temperature of the exiting exhaust gases. You can say that in theory pressure can always be increased, (volume is limited to the volume that can flow through the exhaust manifold and turbine housing), but you have to realize that pressure in the exhaust manifold is accumulated by the piston rising and compressing the exhaust gases in the combustion chamber. Increase this pressure, and your reducing the power created by one of the other strokes, decreasing the volumetric efficentcy of the cylinder with all the pressure built up, and potencially exceeding the pressure the piston is able to create by the given compression ratio (very very unlikely, as the motor will seize at this point due to a 0% VE). The general rule of thumb (according to fp I believe) is for exhaust manifold pressures to never exceed 133% of intake manifold presure. This would limit pressure of a car running 30 psi to 45psi. After calculating the surface area of the turbine wheel, the volume flow of the turbine housing, and using this maximum pressure efficentcy rating, you would find the energy the turbine wheel could put into the compressor wheel, and using the mass to calculate inercia (good luck, ), you could calculate max compressor wheel rpm.

since no one is going to do that, again, I ask the OP to divuldge some of the information I asked for earlier. When does boost drop of? If we know this we can get an idea for the VE, turbo flow cfms, and a lot of other things.

also, pboglio, I don't think you realize that the compressor housing itself limits the amount of air a turbo can flow. Only so much air can pass through a pipe. Take a small straw and a large straw and drink some drink. What is easier? More importantly, no matter how hard you suck, will the small straw ever give you more than what the big straw is capable of? Thats what I thought. And just because you live in a hell frozen over world doesn't mean the rest of us do. Unless they had the dyno outside or are in a garage that doesn't have heating (they MUST be crazy) I seriously doubt they saw 40 degree air temps at the manifold. I seriously doubt 60 degree air temps at the manifold.

I still think this can't be done, as I don't think the turbo can hold that much boost for a long enough time to create that much power.

I don't even know were to begin with all this intake manifold bs, other than to just say, pressure ALWAYS flows from areas of high pressure to areas of low pressure. If a turbo flows less pressure than the manifold has to "add" 6-8 psi, your on drugs.

 

[tkelly27]

also, pboglio, I don't think you realize that the compressor housing itself limits the amount of air a turbo can flow. Only so much air can pass through a pipe. Take a small straw and a large straw and drink some drink. What is easier? More importantly, no matter how hard you suck, will the small straw ever give you more than what the big straw is capable of? Thats what I thought...

If a turbo flows less pressure than the manifold has to "add" 6-8 psi, your on drugs.

I think if you check pboglio's profile, you'll see that he probably knows the simple straw theory you've put up. Hell, he might even be the kid that was showing up while I was skipping fluid dynamics to sleep off my hangover (I still passed!). Anyways, that's incompressible flow, when you get into compressible flow things can get weird. This is what he was trying to point out with the temperature thing. Suck a denser fluid through the smaller straw and you could get significantly more mass transfer without even trying that hard. Go to supersonic flow and everything flips upside down. Small straw going into big mouth accelerates, while the big straw might still be in the subsonic region.

I wish I were on drugs! I might be getting to sleep! Positive manifold pressure is not unheard of when using resonance tuning, I've even heard as high as 3psi on a naturally aspirated engine. I can only imagine with a stiffer spring (more dense air pressure in the plenum due to boost) and pressure surges due to the turbocharger singing it's death knells there could be larger spikes. Maybe there isn't though, I really don't know what the deal is with resonance tuning in forced induction applications. It's gotta be something though, otherwise runner length shouldn't matter at all.

If you believe this is some fabrication of the dyno, then who has the legit 16g record? It's going to be over 400whp. Why do they have 4xxwhp and lots of people can't break 300, let alone 350.

Someone else has to have this combination of parts out there. Let's steal their car, pull the vacuum line going to their wastegate and run it on the dyno until it breaks or we get 450hp.

I kind of don't like the "secrets" thing though. I think of racing secrets like the Pen and Teller clear cup and balls trick. They can put it out in the open for everyone, but only they can pull it off. *shrug* they're your secrets though, do with them what you please : D

 

[pboglio]

Pickens,

Very good point. I never did a power calculation to see if it was even possible to run that low of a compressor efficiency. Here's what I come up with:

Compressor power at 30 psi, 50 lb/min massflow, 65% comp efficiency, 70*F inlet temps = 108 h.p.

Compressor power at 30 psi, 50 lb/min massflow, 55% comp efficiency, 70*F inlet temps = 151 h.p.

If the car were laying down 500 h.p. at the crank roughly, then the exhaust would contain enough power in BTU's equivalent to 160 h.p. available to power a turbine. I'm using the assumption that 44% of the total BTU's show up at the crank & 14% of total BTU's are dumping out the exhaust ready to be utilized by the turbine.

With a turbine efficiency in the 72% range (taken from a GT28RS), the turbine could generate about 115 h.p. to the compressor, mechanical friction losses in the shaft not withstanding.

 

[dsm-onster]

I wish I were on drugs! I might be getting to sleep! Positive manifold pressure is not unheard of when using resonance tuning, I've even heard as high as 3psi on a naturally aspirated engine. I can only imagine with a stiffer spring (more dense air pressure in the plenum due to boost) and pressure surges due to the turbocharger singing it's death knells there could be larger spikes. Maybe there isn't though, I really don't know what the deal is with resonance tuning in forced induction applications. It's gotta be something though, otherwise runner length shouldn't matter at all.

Oddly enough more pressure does nothing to affect the speed of sound, so resonance tuned runner lengths are the same for n/a or boosted intake manifolds, if the temperature remains the same between the two. It's the temperature that affects the speed of sound. So the speed of sound variable , c, plugged into the runner length and diameter calculation for optimal length needs to be modified depending on intake manifold temps. . . Which changes as boost comes on and throughout high load to redline. In otherwords, a different intercooler can drastically affect optimal runner length (water injection definately included), or just an unusually cold day. A different boost can affect optimal length, but only because more or less heat is developed in the aircharge.

The higher the aircharge temp, the shorter the optimal runner length. The higher the duration, the shorter the optimal runner length. So most leave runner length as short as possible, hoping that at the hottest temp their intake manifold charge is, the runner length is close to the particular c value. I think it should be calculated and delt with, too. Just because it's difficult to predict doesn't mean it shouldn't be.

All this does is increase VE of the system the turbocharger compressor is trying to fill.

 

[red91gst]

Ambient air temps in the shop that day were 78*. Its a MAFT car so no monitoring of intake air temps or intercooler effciency. 30psi falling to 22 or so at redline. AFRs fairly fat at 11.3:1 pretty much the whole way. Timing around 17* at peak torque advancing to 24* at redline.

Hope this helps a lil

 

[dsm-onster]

Thanx, Nate .

 

[dsmsucks]

I have to say you guys are VERY smart and know your stuff. I feel so out of place

 

[delta448]

Ambient air temps in the shop that day were 78*. Its a MAFT car so no monitoring of intake air temps or intercooler effciency. 30psi falling to 22 or so at redline. AFRs fairly fat at 11.3:1 pretty much the whole way. Timing around 17* at peak torque advancing to 24* at redline.

Hope this helps a lil

I'm no where near your level of comprehension Nate, but do you think the tune is as aggressive as it could possibly be?

Y or N, (not asking for specifics) Are there any hard parts, or any "special customizations" to other engine systems that weren't mentioned that may have helped achieve the power level (read: lower bsfc; lower pumping losses), or are we looking solely at the tune and only the non-OE parts you listed previously?

BTW, -if you say you did it, in my mind you did, end of story. Congrats! Seriously, what do you really have left to prove that anyone would think you'd ever make this up?

I respect that some of your tuning secrets should be kept secret, and I would really just like to see people start giving credit where it's due.

 

[tstkl]

ok, so I don't know what his actual redline is, but Im assuming he means 22 psi by 7250 (about where the dyno graph ends). This would mean that there are 3625*4 combustions per minute. 14500 * 1.997/4 * VE (I'll get to this later) * (22+14.5)/14.5 (I believe someone said that they were located at 500 feet above sea level which equates to 14.5 psi barometric pressure). This gives you the number of liters per minute the car is consuming. For 100% VE, thats 18222.625 liters. 1 liter = 0.0353146667 cubic feet, so thats 643.525928 cfms. Since we all know cars don't run at 100% VE, we can assume between 85% and 95% (although motors can get high, at the redline they have a tendency to drop). This gives us a range of 546.9970388-611.3496316 cfms.

Compressor maps: CFM vs. LB/Min - TurboBuick.Com

That being said, I believe the Turbonetics curves are lb/min at 85F and 1.5" Hg vacuum. At those conditions air density is 0.069 lb/ft3, so cfm * 0.069 = lb/min, example 600 cfm * 0.069 = 41.4 lb/min.

Im too busy with hw to do the calculations based on air temps and such for our specific case, but the difference shouldn't be too much.

obviously at peak power numbers could have been higher, but the graph looks like close to exactly 50 hp was lost from the peak, and honestly I'm baffled that all the numbers add up. I mean, I just never saw that little thing flowing that much air, and Im still partcial to believing that a different turbo, nos, water injection, or some other trick was relied on heavily. I think its kinda immature to refer to these "secrets" like your some professional who thought of these things yourself. The combustion engine has been around for over 100 years, and Im sure that during the turbo formula 1 age, amoung other times, any of your "uber technical secrets" were used before you had your "flash" of brilliance.

Until you fess up Im still calling bs. Nos, water, propane, something had to have been used.

 

[red91gst]

Since we all know cars don't run at 100% VE, we can assume between 85% and 95% (although motors can get high, at the redline they have a tendency to drop

Incorrect.

It is VERY easy to get a turbo motor over 100% VE, and also easy to get an N/A V8/V6/I4 over 100% VE. I have engine dyno graphs of several small block and big block engines well over 100% with low BSFC numbers.

Peak VE, (and peak cylinder pressure of course), will occur at peak torque.

At redline, it is a different story as most motors don't make peak torque at redline, but it is still very possible to have well over 100% VE at redline.

 

[red91gst]

Until you fess up Im still calling bs. Nos, water, propane, something had to have been used.

There is nothing to "fess" up to, I've stated everything truthfully. E316G and C16, no secrets.

Its all smoke and mirrors ;-).

 

[red91gst]

I'm no where near your level of comprehension Nate, but do you think the tune is as aggressive as it could possibly be?

Y or N, (not asking for specifics) Are there any hard parts, or any "special customizations" to other engine systems that weren't mentioned that may have helped achieve the power level (read: lower bsfc; lower pumping losses), or are we looking solely at the tune and only the non-OE parts you listed previously?

BTW, -if you say you did it, in my mind you did, end of story. Congrats! Seriously, what do you really have left to prove that anyone would think you'd ever make this up?

I respect that some of your tuning secrets should be kept secret, and I would really just like to see people start giving credit where it's due.

Thank You.

Its no where near as aggressive as it could be. Don't forget, this is a STOCK 7-bolt and a daily driver, we wanted to keep the tune safe and realiable.

There are no special parts or super secrets. Everything on the car can be purchased right from the vendors that support this site.

 

[JayRolla]

Thank You.

Its no where near as aggressive as it could be. Don't forget, this is a STOCK 7-bolt and a daily driver, we wanted to keep the tune safe and realiable.

There are no special parts or super secrets. Everything on the car can be purchased right from the vendors that support this site.

What are your plans on the motor. Low or high compression? 2.0L or stroker?

 

[red91gst]

What are your plans on the motor. Low or high compression? 2.0L or stroker?

High compression 2.0l

 

[SBR Joe]

Thank You.


There are no special parts or super secrets. Everything on the car can be purchased right from the vendors that support this site.

Hoegaarden


Joe

 

[tstkl]

Incorrect.

It is VERY easy to get a turbo motor over 100% VE, and also easy to get an N/A V8/V6/I4 over 100% VE. I have engine dyno graphs of several small block and big block engines well over 100% with low BSFC numbers.

Peak VE, (and peak cylinder pressure of course), will occur at peak torque.

At redline, it is a different story as most motors don't make peak torque at redline, but it is still very possible to have well over 100% VE at redline.

Volumetric efficiency - Wikipedia, the free encyclopedia

I already accounted for absolute manifold pressure, in the case I calculated, you can't have a VE multiplier of more than 100%.