nitrodann

Im not bullshitting anything, I think it will work, my experience says it will, the maths and chemistry says it will, experience tuning n/a and seeing gains says it will (despite the turbo being COMPLETELY tapped on all n/a setups). And all im saying is I think it will work and Im going to try it before the turbo gets upgraded.

No bullshit just what I think, which as far as I can work out is what you are doing also, posting what you THINK.

Dann

krissetsfire

iTrader: (1)

I don't doubt there will be some kind of increase. the point is that there is a very large restriction killing the efficiency. If you read my posts i explain why you won't get to 350. not that there won't be any gains.

Braineack

iTrader: (62)

I wonder why people don't put single .63 A/R 2560s on their v8s???

albumleaf

iTrader: (7)

It's almost like you can't understand that the amount of input air will stay constant, it doesn't matter that the turbo is supposedly tapped out at that point. That said, the more posts like this one that are in the thread before nitro posts the dyno sheets, the more backtracking and hilarious it'll be for me to watch.

Savington

iTrader: (31)

Kids, read this post until you understand why E85 can produce more power despite no increase in compressor flow.

Braineack

iTrader: (62)

if the input of air stays the same, then the turbo will stay tapped out, because we've already found the point in which that mass air flow of the compressor reaches the end of efficient compression, and that was right in the 310rwhp range on a dynojet.

You'll see a big bump in mid range on e85 for sure.

Then as the turbine housing/wheel has to deal with greater amount of volume of exhaust gasses, from the lower stoichmetric value of the e85 fuel, it might even tap out even sooner as it cant efficiently pass enough gasses through the small housing. When you surpass the 15 lb/min gas turbine flow peak efficiency of a .64 A/R 2560R turbine housing, you'll start increasing back pressure, lowering peak output.

So, I'd expect a big bump in low/mid range power compared to Paul's Monster...but maybe even loss of peak HP as the turbine and compressor became overwhelmed sooner, and you weren't able to use the RPMs to increase the peak HP; since the torque might drop off much faster and much sooner.

But even if it doesn't I wouldn't expect any huge increase in peak HP number in what Paul achieved without going to a bigger turbine or turbine housing.

Braineack

iTrader: (62)

I was never doubting the net energy increase due to the lower stoich point.

I'm doubting that even with the increased energy output, if you still use too small a turbo for the power goals, it cant produce anymore power than it can produce before the turbine is overwhelmed increasing backpressure or before the compressor just dumps hot air without any extra mass volume.


It's also why my gas stove can boil water so fast, it has insane amount of BTUs.

albumleaf

iTrader: (7)

I'll take Mass Balance for $500

18psi

iTrader: (76)

/\ The above 2 of Scotts posts are exactly what I've been trying to tell Dann in the past page. You word it better, thank you. I (and many others) have done this on td04 equipped subarus (in which the turbo is way too small for the engine, and its extremely easy to tap it out). The result was a ton of midrange torque increase, but peak power output would never go much higher than a few horses over pump gas figures. Once a larger snail was bolted up it would skyrocket, as expected. I know, not same engine and not same setup, but I think it definitely still applies. All we're talking about is turbo efficiency, and engine VE and how it relates to type of fuel used (or how much energy it has). If anything a 1.6 miata is a terribly flowing engine and I wouldn't expect it to outflow a subaru ej25 by a long shot.

Maybe we're still mis-understanding Dann, but I'm eagerly waiting for results. Hope they are no-nonsense tests that once and for all prove or disprove what we're arguing about.

nitrodann

Braineak, you have completely missed it. It has nothing to do with stoich, I simply referenced it to make a point. Also your belief that E85 may produce more gas for the same HP further shows your misunderstanding about how engines produce torque and how that translates to HP.

Furthermore, it's not important if the compressor side pumps the same mass of air at a greater temperature while the turbine side flows an extra 10% exhaust past its optimum efficiency, as log as the temperature doesn't make the engine knock limited, which on E85 I don't think it will be.

Dann

18psi

iTrader: (76)

What about overspinning the turbo due to pushing both sides off the charts?

nitrodann

No idea what happens in that case. The car will have 3D EBC and perhaps we will find a point that it works best at. Perhaps max compressor flow in mass will occur at 17psi and allowing the wastegate to open rather than overspeeding the compressor and allow the exhaust side to flow through the wastegate will make a difference F'd if I know. But we are going to find out.

Dann

Braineack

iTrader: (62)

I understand how a motor produces torque and how that translates to HP, but you seem to misunderstand how a turbo uses exhaust volume flow to spin a turbine, to spin a compressor, to compress air and increase the density ratio in the charge and how that translates into HP.

Are you suggesting that with an increase in backpressure there is not a reduction in TQ? Because I'd argue that instead of all the energy being used to push the piston down, it not how to expend some to push the exhaust out to overcome the excess pressure.

Also, if there's significantly more fuel being injected per volume of air during each compression, the byproduct also increases; this will spin the turbo sooner and faster, but a turbine has limits... there's published flow numbers for the 2560 turbine housing. If you surpass this point, the turbo's output drops off significantly regardless of magic fairy fuel or not.

I find it very important.

Also keep in mind I'm just an art student...so I hope that makes it feel worse when we can't disprove me.

albumleaf

iTrader: (7)

Jesus Christ.

For the sake of simplifying things, say you have 10kg/min input air and fuel. Assume max power gasoline @ 12.5afr, E85 7.0afr

E85: 8.73kg air, 1.26kg fuel
Gasoline: 9.25kg air, 0.75 kg fuel

1.26 kg E85 * 33.1 MJ/kg = 41.70 MJ
0.75 kg gasoline * 47.2 MJ/kg = 34.9 MJ

Here's the amazing part that you keep looking over. MASS IS CONSERVED. 10kg in, 10kg out.

If you move the numbers closer to stoich, the power output/kg advantage moves down to 3% or so for E85 which isn't quite as encouraging, but the fact of the matter is that E85 will make more power without changing the mass flow rate.

Enginerd

iTrader: (1)

I don't think this is what he's saying. I think he's saying this:

2C8H18 +25O2= 16CO2 +18H20

8.33C2H6O + 24.99O2 = 24.99H2O + 18.66CO2

24.99H2O + 18.66CO2 > 18H2O + 16CO2

For the same airflow in, complete, ideal combustion of ethanol will produce significantly more exhaust.

albumleaf

iTrader: (7)

This is pretty stupid because your masses don't add up.

2C8H18=228g
8.33C2H6O=383.18g

Whoa look at that, the percentage difference in your stoichiometry is similar to the amount in which you were off in mass.

Enginerd

iTrader: (1)

OMFG

That's the point, moron.

dk wolf

HAHAHAHAHA!!!!!!!!!!!!!
this just made this thread.

albumleaf

iTrader: (7)

Holy ****, are you really that ******* dumb? If your MASS INPUTS AREN'T EQUAL THERE'S NO POINT IN COMPARING THE TWO. One apple has less caloric value than two bananas well who the **** cares?

I should show this thread to my old thermo professors, I always wondered what I could do to make them cry. Miataturbo: teaching high school chemistry one post at a time.

nitrodann

Will its mass flow drop off or its efficiency. If it's just its efficiency, then as long as the heat produced doesn't lead to knock limiting then it's inconsequential.

If this happens on the exhaust side the turbine may become a restriction and limit exhaust flow and then we are going to stop making power. However if the turbo is producing x Lb/minute of flow at 17psi but can also produce x Lb/minute at 19psi due to inefficiency surely boost control set at 17psi will result in the wastegate opening and increasing flow through the rear housing?

A reminder of what we are doing here.

Current set is a built 1.6L with a log manifold and a downpipe that is 2", and exits the turbo at a 60* angle, it's not a bend, it's straight 2" that's Ben slash cut.
It then goes into a 2.5" exhaust with a cat,a hot dog and a chambered muffler. turbosmart T boost bleed valve.

On this setup it has made 297whp.

This is being replaced with a tubular long radius 1.5" steam pipe manifold with a low angle collector and at least 3" downpipe and exhaust feeding into a single hotdogs and exiting under the car.
It's getting 3D EBC and I happen to know a bloke who writes firmware for the ECU who's happy to help with whatever I need in this regard.

Dann