Wow what a difference. Heard that BMW is coming out with a 3 Turbo set up 1 being a electric Turbo. Editorial: Tri Turbo and Electrical Assist

 

Hmm. Links not working. I do remember they filed a patent for one a couple months back though.

 

Its working here, I have McAfee firewall and anti virus.

 

Check this out..http://www.mitsubishi-motors.com/cor...004/16E_04.pdf

http://dspace.mit.edu/bitstream/hand.../676953430.pdf

One more I found http://210.101.116.115/fisita/pdf/A033.pdf

 

Yup knock is going to be heavily dependent on mean chamber temperature. By adjusting block/head cooling it looks like they were able to pick up 4* advance on the test bed.

This is why you can stand to pick up so much more power on the same setup by switching to say, an alcohol fuel. At the expense of considerably greater fuel consumption of course.

 

Those links answered my question I asked you earlier but I still think when the warmer temps come back that motor in question is in trouble.

 

Eh. I am sure it will be fine.

You have to remember, there is a huge safety overhead left in on these ECUs. They don't get to aim for peak torque. OE's often have calibrators dedicated specifically to limiting torque production under all circumstances.

That's why these ECUs clamp down on performance when they detect conditions that can produce "excessive" cylinder pressures. Not just referring to knock obviously.

3* advance might make or break a turbo L15, but not NA. Especially since it is coming in on the top end way past peak VE where torque is plummeting and cylinder pressures are considerably lower..

 

Yea, I get it now. Besides the air is less dense in warmer temps too.

 

Does anyone have any inkling as to what the VE is for the L15A? Is it around .9 @ 6000rpm?

 

Based on the stock torque curve, thats pretty close mike.

On the few stock dyno plots I have seen with peak coming in with 87-88wtq @ 4800 and closer to 75wtq @ 6000 its going to be about 85-87% VE.

Thats what the Load/MAP table seemed to say in the FIC as well.

FWIW, those are aligned with some of the numbers I use to match turbos for people with the A1 cylinder head.

 

Well, I had a bunch of pics forwarded from my phone to my email to show the progress made lately. Including the first attempt at mounting both turbos (has since been re-desgned), the chassis bracing, the new brakes with SS lines, sway bar, rotating assembly and modified oil pan, urethane mounts/bushings, springs etc.

Only two pictures made it and one is justthe new brake bits for the DSM, and I am way too tired to do it again since my phone is ancient and it took over an hour. F*cking T-Mobile.

So here is all I got for an update - Enjoy:


Cost was only $225 + $17 for UPS ground from TireRack.com

The Goodridge SS Line kit was cheap as hell too through these guys (~$125)
http://www.hawkpadsdirect.com/Goodri...r20027.434.htm

 

At peak torque its 87 percent efficient. A 10.4 compression would have a Mep of 195 at 100 percent VE. Torque/Cubic inch *150.8 =mep. All Honda stock motors have a MEP of 173-175 at peak torque. Even the K20 has a low mep with higher compression.


DSM, I would like to learn how to read Load/Map to figure VE from those numbers.

 

Can torque alone determine volumemetric efficiency? I thought the torque curve just gives us an idea of what the VE curve looks like. Otherwise how would we account for the differences in brake specific fuel consumption

 

There are many ways you can do it, what is correct is subject to interpretation. I use a few different ways personally depending on whether we are dealing with an NA or FI piston engine, or what information on the engine I have available.

MEP/BMEP and BSFC will give you the theoretical numbers, but dyno numbers work very well for a practical application on an individual car.

Depending on how you look at the situation, for instance, from the ECU's "point of view" peak torque will be 100% VE.

In terms of AVF/TVF x 100, peak would be in the high 80's low 90's for an individual L15A depending on atmospheric conditions.

Which is why I use the Load/MAP tables.

Airflow, Fuel Flow, Torque and Power are all ways to do it. If they don't all come up relatively close to each other, something in your math is off or your base data is wrong. They should all be in the same ball park.

 

Thats what I was thinking about. What if a hypothetical engine is not operating under ideal circumstances. Say it has a flaw, like higher than normal frictional loses for whatever reason. If you tried to determine the VE from a dyno the VE numbers would be artificially low. A correspondingly poor BSFC would give you an idea of what the actual VE looks like... just trying to make sure I understand these things by applying them to each other. On an interesting note the GE8 sometimes gives me an ABOVE ambient MAP in the manifold's 'tuned' 3000-4000 range.

 

I think your confusing VE to thermal efficiency. You run the Fit with 87 and produce the same Torque but use more fuel to get it. VE is related to hard parts and thermal efficiency's is related to temp corrections,knock and barometric pressures etc. With out changing parts the VE remains the same but the BFSC is related to conditions. Yes they are related but only to the point of fuel used to get the fixed VE.

 

Actually I might just be confused all together. I thought volumetric efficiency was simply how good the engine is at getting its physical displacement actually in the combustion chamber.

Say a single cylinder displaces 374 cc. but due to restriction and turbulence from the valves, intake manifold, throttle body, etc. It only fills up with 336cc of air each stroke at say 6000 rpms. Then it would have a VE of ~90%. Volumetric efficiency is just how good the engine is at getting the air that it should be getting.

What was on my mind is that a lot of 'stuff' happens between that air entering the cylinder and power being transfered from the wheels to the rollers on the dyno. So even if an engine is operating at 100% volumetric efficiency and drawing in every bit of air that it physically displaces, some of the energy that is produced can be lost for reasons not relating to VE before that energy makes its way to the dyno.

So I asked myself how we could tell if power is less than we expected due to poor VE or some other factor. The amswer that came to mind was BSFC. In other words how much fuel it takes to make a given amount of power. It came to mind that by combining brake specific fuel consumption WITH torque we can help to eliminate some of the factors that might be robbing power before it even gets to the wheels.

So again back to 2 hypothetical engines. Both engines have the same displacement, timing, combustion chamber design, etc. Both of these engines have 100 percent volumetric efficiency from the factory. In 1 engine I place a restrictor plate in the throttle body that reduces volumetric efficiency to 90%. In the other engine I do not place a restrictor plate. I leave it at 100% volumetric efficiency. But I drain the oil and fill it with chocolate syrup. This imaginary chocolate syrup is extremely viscous, heat resistant, and still adequately lubricates the engine. On the down side, the high viscosity increases frictional losses up to 10% of the overal torque output. Or we could just say that the drivetrain has more 10% more loss than the other engine. Either way these losses play out similar getting worse as rpms increase. Just like VE losses getting worse as rpms increase.

So now that I've got these 2 engines setup let's say that I run them both on a dyno and hand you the printouts and ask you what the VE of each of these engines is. You would tell me that both have a VE of 90%. If I then handed you a printout of the brake specific fuel consumption, you would notice that 1 of the engines was consuming approximately 10 percent more fuel to produce the same amount of power. Now if both engines are set to run at the same AFR, The only way 1 engine could use more fuel to produce the same amount of power is if it's also using more air... so if torque tells us one story but fuel tells us another, VE is likely not the culprit.

Now of course I'm trying to leave out as many variables as possible like air density/temperature, exhaust scavenging, etc.

Actually I'm pretty sure I just went insane instead.

 

I guess we will have to wait for DSM to correct us. Now I am confused. I do know that using the least amount of fuel that produces the most torque is where you want to be.

I see your point but I think that is thermal efficiency because no parts in the motor has changed.

 

What I am aiming at is the relationship between VE and torque. In my limited understanding VE is not concerned with torque. Let's use another hypothetical engine. This is a single piston 4 stroke engine with 250cc displacement. I disconnect the plug wire from the spark plug. Then I turn the engine over by hand. If the engine sucks in and spits out 250cc of air (ignoring density) every 720 degrees then it has 100% VE even though it is producing no torque. If it takes in 125cc worth of air then it is operating at 50% VE.

VE= (actual air flow) / (theoretical air flow).

On the other hand

Torque = VE + (other factors)

Fortunately VE is usually the largest factor in torque production so we can get a good picture of what it looks like from the torque curve. But, in order to determine the VE from torque alone, then (other factors) has to be exactly the same in every single engine for brake torque and every single engine, differential, and transmission for wheel torque. But that is impossible! It's for that reason that I suspect that a formula that attempts to calculate VE from torque alone can never be perfectly accurate.

 

I got it thanks, VE changes because the air changes. I was using both VE(air) and thermal efficiency's (fuel) to figure 87 percent at max torque but with more air or fuel that would change.