Any ideas for tuning a ka-t with an safc????

[sil80drifter]

if i made pancakes, would you believe MY advertisign that said that pancakes are more nutritient than salad?All this site says is the same thign over and over and it can be simplified to this: A turbo 2 liter made same power as a NA 3 liter. Comgrats. There is no way to beat physics. HP comes from fuel and air. you can force more air into a 2 liter with a turbo, and make it perform as a 3 liter. Quote from that site oyu posted:

"The turbo — more relevant than ever to modern needsTurbochargers harness and recycle the energy produced by automobile engines, by using exhaust gas energy (speed and heat) that would otherwise be lost and transforming it into power. As a result, turbocharged engines deliver significant fuel cost advantages over their naturally-aspirated counterparts. Because a turbocharger delivers more air to the engine, fuel combustion is easier, more thorough and therefore cleaner.

For gasoline passenger cars, where the trend is for smaller displacement engines, turbos contribute to CO2 reduction by delivering 10-20% better fuel efficiency than a non-boosted car of equal power. In turbo diesel vehicles, the fuel efficiency gain is 30-50% better than a non-boosted gasoline vehicle. These gains help meet the increasingly demanding emissions standards being applied in the US, Europe, and Asia."

Thats great. The turbo chargr delivers more air to the engine...? ok, but it does so at a COST. It is spun by exhaust, the exit of which is what makes an NA engine run. There is a reason why the Civic DX is the most fuel efficient (notice NOT the most powerful) car out there. It is tuned to consume the LEAST gas under most conditions, not just under WOT. NA cars will always be more efficient, while turboed cars will be more powerful. (Same car, same engine, cane be either tuned for economy OR power, and it'll either be fuel efficient OR powerful, not both).

sil80

[240SicknessX]

^^ i agree.

yes, if you run c16/simalar race fuel or alcohol injection you can run leaner AF's because of the slower more controlled burning of the fuel that you have. thus you will make more power like what WD said.

when buying a turbo it is just as important to plot your turbine maps as your compressor maps. if you have a huge compressor wheel and a smaller turbine wheel, the compressor will be able to feed engine more then enough air, but when the exhaust trys to escape past the turbine it could cause too much of a restriction which will actually limit the capabilities of the compressor side. make sure with in reason that your wheels are realitivly matched.

[deezlins]

A turbo does not increase volumetric efficiency of an engine. Volumetric efficiency deals with the volume of air the engine can flow, but when you add a turbo and compress the air it wont give it more volume, it just makes the volume more dense.

The BSFC (brake specific fuel consumption) of a turbo motor is usually going to be higher (worse) than that of a NA motor.

Theres been dyno tests that have proven that fairly dramatic changes in afr do not have a significant affect on power output from the engine. Ive seen it myself on a dyno with the car being held at a certain load and rpm and changing just the afr didnt make a significant affect on power.

[WDRacing]

I guess your correct, when adding a leaner mixture only, you probably won't gain any power. However, who the hell just leans out a mix? The best way I can think of to lean out your mixture is to add boost!!!!!!!!!!!!!

I do disagree with the VE not improving on Boost though.

What the hell was this thread about??? LOL.

[deezlins]

The turbo wont increase VE because it wont increase the actual volume of air flowing through your engine, it only increases the density of said air. Say you had an engine with 100% VE NA, then you had the same engine with a turbo on it and it still had 100% VE and it is pushing like 10 psi, so both engines cylinders are completely full of air. They both have the same volume of air in the cylinder, but the air in the cylinder of the turbo engine will be much more dense.

haha, yeah we did get a little off topic, but talking about this stuff is fun
Modified by deezlins at 3:25 PM 4/1/2005

[SonyPete]

Deezlins your comparing a physical dimension to density, and density will over come physical dimensions. Of course you'll never reach 100% VE. But by adding a turbo your VE jumps up, due to being able to cram in more air. A turbo allows you to get closer to a 100% VE with out having all conditions perfect in theoretical situation of a 100% VE.

And comparing a 100% VE N/A Engine to a 100% Turbo Engine is just not right hahah, very unlikely to ever happen maybe with another 50+ years of technology. Though the turbo engine would more than likely reach it before the N/A.

[D1 guy]

Yeah I started this thread about awhile ago and now its crazy lol. Keep posting guys!!!! I dont know what its about, but it sure is fun hearing you guys ramble on and on. Since were basically off topic, Whats the largest width tires you can get on the back of a 93 240 and a 97 240, without rolling the fender?

[JRL]

Thanks for the aem windows. That will help a lot!!! You guys are awesome!

Those arent AEM windows. What your looking at is a modded stock map with the knock feature still enabled. So dont copy the blue part. Subtract 128 from the blue part to find out the actual timing.

[JRL]

Whats the largest width tires you can get on the back of a 93 240 and a 97 240, without rolling the fender?

I think its like 9.5 and 10.

[Master_Tao]

I think its like 9.5 and 10.

is that 9.5 on the s13 still able to fit coilovers?

[deezlins]

ok, maybe that wasnt the best example."As you increase the pressure of a fluid, the amount of energy required to move it through a restriction increases. It would appear that with the increased energy of the fluid under pressure, that the increase in energy necessary to overcome the restriction would be irrelevent because of the higher force applied by the fluid on the point of restriction. The truth, however, is that the "drag" created by the restriction becomes greater and greater as pressure is increased. Keep in mind that pressure would not increase across the restriction if this were not the case. You would (in theory) be able to keep increasing the rate of flow infinitely without an increase in pressure before the restiction. Think about it a little, and it will make sense. " Actually the turbo will decrease VE, but the air is so much more dense that it overcomes that.

also there are NA engines that have 100%VE and even up to 110% VE, they have very specialized heads and cams and stuff.

[DRIFTEADOR]

if i made pancakes, would you believe MY advertisign that said that pancakes are more nutritient than salad?

well, they are. lettuce is no more nutricious than water. healthier? probably not

you're missing what i'm saying though, im not comparing a turbo ls1 to a vtec economy. I'm comparing a ka to a ka-t. the same motor with a propertly tuned turbo setup will be more fuel efficient than its counterpart with no turbo at cruising speed, not at wot. at wot you are burning more fuel because you're making more power, cruising with the speedo pegged at 70mhp takes less throttle from the turbo setup to retain the same speed. who would you need to hear it from to believe it?

http://encyclopedia.laborlawtalk.com/Tu ... er...boost DOES increase volumetric efficiency past 100%. making it "the replacement for displacement"

[onosqv]

well, they are. lettuce is no more nutricious than water. healthier? probably not

you're missing what i'm saying though, im not comparing a turbo ls1 to a vtec economy. I'm comparing a ka to a ka-t. the same motor with a propertly tuned turbo setup will be more fuel efficient than its counterpart with no turbo at cruising speed, not at wot. at wot you are burning more fuel because you're making more power, cruising with the speedo pegged at 70mhp takes less throttle from the turbo setup to retain the same speed. who would you need to hear it from to believe it?

There has to be something definately wrong here...

at cruising speed: if the turbo is not under boost -> the turbo is a restriction -> no way in hell it is more efficientif the turbo is under boost -> sure, the "VE" is greater -> more air BUT also means more fuel

fuel efficiency is determined by Air-Fuel ratio... RATIO

The only time I've read in books/articles/etc by "experts" that a turbo is more fuel efficient is when it is compared to a larger n/a engine (i.e. cargo ships) or when atmosphere air is below normal (i.e. airplanes/mountain driving). The reason here why turbo's are more efficient is because the N/A engine is no longer performing in it's "ideal" environment.

More power w/ the same motor (i.e. turbo/supercharger) costs fuel.

If you are getting better fuel efficiency from a turbo w/ the same motor, GOOD FOR YOU. All that means is that you tuned your turbo better than you tuned your N/A.

[onosqv]

and to finally beat this **** to death:

case example:

chevy cobalt 2005:

supercharged version: 2L engine curb weight: 2900 lbs mpg: 23 city/29 highway

ls version: 2.2L engine curb weight: 2900 lbs mpg: 24 city/32 highway

Source: caranddriver.comls: http://www.caranddriver.com/article.asp ... e_number=4

ss: http://www.caranddriver.com/article.asp ... e_number=2

You can do the same comparision w/ the 300zx n/a & tt. I didn't list those because I couldn't find info in the given time. And don't give me bull**** that turbo is more efficient that supercharger.

So now, will you please STFU!!! -

[DRIFTEADOR]

at cruising speed: if the turbo is not under boost -> the turbo is a restriction -> no way in hell it is more efficientif the turbo is under boost -> sure, the "VE" is greater -> more air BUT also means more fuel

If you are getting better fuel efficiency from a turbo w/ the same motor, GOOD FOR YOU. All that means is that you tuned your turbo better than you tuned your N/A.

yes, the exhaust is a restriction to the exhaust stream whether at idle or at wot, however you need to remember that the compressor wheel is spinning with the exhaust wheel. i couldn't tell you at what load/rpm a turbo's compressor overwhelms the exhaust restriction so the engine works less to pump the same amount of air (therefore making it more "efficient"), but in my case (1.8l w/ 57 trim t3/t04e, rather large turbo for such small displacement which theoradically would mean more of a restriction) i could get more mileage on long freeway trips (Dallas>Houston) than epa ratings or before turboed, as long as i stayed in open loop mode. I did have tuning done by one of the best, if not the best tuner in tx (anthony palo from team norad if anyone cares), but #1, i really doubt a self learned guy in his 20s can come up with a better tune in a couple of hrs than Honda engineers in years of testing and #2 it wouldn't matter since the stock program still controls fuel delivery in open loop mode (chipped ecu, much like biki's a few posts up).

i can't find any articles by someone you'd consider an unbiased "expert" but just so you know honeywell, aka garret (http://www.honeywell.com/sites/ts/tt/turbo_feature.htm) and turbo international (http://www.turbointernational.com/turbos.shtm) are some of the biggest names in turbochargers. I'd consider them credible sources.

and fyi, bsfc is a measure of engine efficiency and a higher number= a more effiecient engine

[Jookmasta]

i can tell u from personal experience, with a turbo, the engine is less efficient especially when referring to MPG. remember that with us safc guys, our fuel maps are constantly being used so our afrs are alot richer than what stock is...... this increase in fuel is good for the turbo, bad for the MPG. ive personally gone down about 4 MPG; i basically get 50 miles less to a full tank of gas........so im living proof of this as are others on this board

[deezlins]

"Keep in mind that VE tables expressed for a given engine include the ambient temperature, pressure, and humidity (normally corrected to standard.) Otherwise, VE changes with pressure as I've described above"

If you ever use Desktop Dyno 2000 you'll notice when you build a virtual engine with a turbo or supercharger the VE goes down as boost goes up (it's not a software mistake)

and fyi, bsfc is a measure of engine efficiency and a higher number= a more effiecient engine

With a BSFC of .50 your engine would consume .50 lbs per hour of fuel for every horsepower it makes, so if you had an engine with a .40 BSFC (.40 lbs per hour of fuel for every hp) that means its using less fuel for each hp. That means that the lower the BSFC is, the more efficient your engine is.

[deezlins]

edit: double post

[DRIFTEADOR]

"Keep in mind that VE tables expressed for a given engine include the ambient temperature, pressure, and humidity (normally corrected to standard.) Otherwise, VE changes with pressure as I've described above"

ok...

Quote »If you ever use Desktop Dyno 2000 you'll notice when you build a virtual engine with a turbo or supercharger the VE goes down as boost goes up (it's not a software mistake)[/quote]either there is a mistake in the software of you are not reading it correctly.

http://www.epi-eng.com/ET-VolEff.htm

"In a four-stroke naturally aspirated engine, the theoretical maximum amount of air that each cylinder can ingest during the intake cycle is equal to the swept volume (displacement) of that cylinder (0.7854 x bore x bore x stroke). Since each cylinder has one intake stroke every two revolutions of the crankshaft, then the theoretical maximum volume of air it can ingest during each rotation of the crankshaft is equal to one-half its displacement. The actual amount of air the engine ingests compared to the theoretical maximum is called volumetric efficiency (VE)."

a force inducted motor can fill the cylinders with more air/oxygen than if naturally aspirated. i dont see how you can refer to that as decresed ve

Quote »With a BSFC of .50 your engine would consume .50 lbs per hour of fuel for every horsepower it makes, so if you had an engine with a .40 BSFC (.40 lbs per hour of fuel for every hp) that means its using less fuel for each hp. That means that the lower the BSFC is, the more efficient your engine is. [/quote]ok, i admit it, i was wrong in bringing up either of those terms in reference to fuel efficiency (getting more [miles] from your fuel) because clearly, they both measure engine efficiency (getting more [hp] from your engine/displacement). in both terms a turbo motor is more efficient by making more max power but not necessarily more or less fuel efficient in other scenarios (like part-throttle). my only valid point then, is that a turbo recycles energy that otherwise would have been lost, and my own experiece, if you could consider that valid. i'll try to find out more...maybe a mod should split the thread where we veered off the original topic.

jookmasta, i doubt youre running off your safc maps all the time. if anything, you should be in open loop longer than with, say a jwt setup, since you need a higher maf reading before your ecu will make the switchover, as described in a previous thread.

[Jookmasta]

well i see the highway everyday and my throttle % stays at least at 20 if not higher. now structure posted that the safc low and high throttle maps mesh at certain throttle percentages. I know im running the safc maps most of the time due to the correction factors i see on the safc......trust me, +1% on the safc means its running the safc map.

[deezlins]

Im not saying that a turbo wont put more air into your engine, im saying that it just makes the air denser, but doesnt increase the volume. You're really getting more air, but technically the VE wont increase.

[DRIFTEADOR]

as long as youre in open loop the ecu will make necessary changes to get you as close to 14.7 afr as possile. If youre in closed loop cruising theres something wrong. btw, if your gauge reads vacumm, what does it read highway cruising on flat road?

Im not saying that a turbo wont put more air into your engine, im saying that it just makes the air denser, but doesnt increase the volume. You're really getting more air, but technically the VE wont increase.

VE doesn't mean increased cylinder volume, it means increased efficiency from the same cylinder volume. the displacement remains the same; the power you can extract from it changes.

[:: orion ::]

Im not saying that a turbo wont put more air into your engine, im saying that it just makes the air denser, but doesnt increase the volume...

Huh...?

That's backwards.

A turbo compresses air and forces it into your motor. "Compresses".

As in...take a large volume, compress it into a smaller volume so that it all fits into your cylinder.

And you simply CANNOT make twice your current power without a larger VOLUME of air (e.g.: 155rwhp N/A KA versus 300rwhp 12psi KA-T)

In fact, most turbos make the air entering your motor LESS dense...b/c a compressor heats air...and hotter air is less dense. Intercooling is a factor here, but even the best are at most ~70-75% efficient, so you're still adding ~25% of the heat a compressor will generate.

- Brian

[sil80drifter]

You are still missing the main point. A turbo can make a smaller displacement engine make more power than it's original NA form (HENCE replacement for displacement).

The ONLY thing a turbo CAN do is push more air into the mix. So the ONLY thing it can do is make the mix leaner OR when you are hitting the safety margin for leaning it out, you add more fuel and THEN you are producing more power. The following statement will always hold true:

THE BEST WAY TO INCREASE MPG IS TO LEAN THE AFR OUT.

You do NOT need a turbo to do this. It will NOT do this better than an SAFC will by altering the ECU signals.

An NA engine running 14.7 AFR is NOT more efficient at 3k rpms than a turboed engine (same dicplacement etc) at 3k rpm. In fact they should be at BEST making the same power, if the FI engine is not boosting, it will probably make a bit less, and if it is, it will consume more fuel than the NA engine.

[deezlins]

Huh...?

That's backwards.

A turbo compresses air and forces it into your motor. "Compresses".

As in...take a large volume, compress it into a smaller volume so that it all fits into your cylinder.

And you simply CANNOT make twice your current power without a larger VOLUME of air (e.g.: 155rwhp N/A KA versus 300rwhp 12psi KA-T)

In fact, most turbos make the air entering your motor LESS dense...b/c a compressor heats air...and hotter air is less dense. Intercooling is a factor here, but even the best are at most ~70-75% efficient, so you're still adding ~25% of the heat a compressor will generate.

- Brian

How can you get alot more air into the same size container, you have to compress it, and when you compress it, it gets more dense. To fit the air in, it would have to become more dense, or either it will expand its container.

And you simply CANNOT make twice your current power without a larger VOLUME of air (e.g.: 155rwhp N/A KA versus 300rwhp 12psi KA-T)

So youre saying that if i had two same volumes of air, and one was 100 times denser than the other that you couldnt make twice the power with it?

[deezlins]

as long as youre in open loop the ecu will make necessary changes to get you as close to 14.7 afr as possile. If youre in closed loop cruising theres something wrong. btw, if your gauge reads vacumm, what does it read highway cruising on flat road?

VE doesn't mean increased cylinder volume, it means increased efficiency from the same cylinder volume. the displacement remains the same; the power you can extract from it changes.

In open loop the ecu does'nt use feedback from your oxygen sensor, its just going off the value it has programmed. Closed loop is when the ecu gets input from the oxygen sensor and adjusts itself accordingly.

VE is basically the volume of air your engine is actually getting into the cylinder vs. the volume of your cylinder.

[:: orion ::]

*** CAUTION, long post ahead... ***

How can you get alot more air into the same size container, you have to compress it, and when you compress it, it gets more dense. To fit the air in, it would have to become more dense, or either it will expand its container.

...

So youre saying that if i had two same volumes of air, and one was 100 times denser than the other that you couldnt make twice the power with it?

Excuse my ignorance...I was using VOLUME instead of MASS.

It should have read:

"And you simply CANNOT make twice your current power without a larger MASS of air (e.g.: 155rwhp N/A KA versus 300rwhp 12psi KA-T)..."

...

I thnk we both has just enough understading of this to confuse ourselves...so a quick trip to wikipedia.org/wiki/Density enlightened me.

Basically...

Twice the density, half the volume. As you decrease volume, density increase. Simple. But that's leaving out 1/3 of the equation...

I'm saying you're decreasing volume (compressing air) to squeeze more air into a cylinder....you're saying that increasing density is the only way...

And since (I asusme) we're not physics majors...then we're missing the big part of the equation...MASS.

Density = (Mass / Volume)

Only way to make more power is to have a greater MASS of air. All we've been discussing is changing the size of the container it fits in...same mass, same power. Twice the mass, twice the power potential.

Density of air is 1.2 kg/m3 (std pressure and temp)

So if we have a mass of air that is 2.4kg, then it occupies 2cubic meters of space.

2.4/2 = 1.2

If we compress it to fit in 1 cubic meter, then it's twice as dense (2.4kg/m3), but has NO MORE potential to make power...so what you've been saying, that more dense equals more power...is FALSE.

And what I said was that we needed a greater volume or air...also not exactly true, but along the right lines.

See, we CANNOT change the density of the air we drive in...but we can make a bigger volume of air enter our motor by compressing it.

If you rearrange the equation to solve for MASS, then you get:

(Density x Volume) = MASS.

What I've learned is important is the MASS (hence, we use a MAF)...

We cannot double the density without changing the volume...no way around that. And since air has a constant density under a given pressure and temp...all we can do is take air of a fixed density (based on outside ambient temp, and atmosheric pressure where you live), and double the volume that goes into the motor.

So the density is 1.2...we CANNOT change that until the pressure changes.

*BUT* we CAN compress 4 cubic meters of air into our motor using a turbo (as compared ot the 2 cubic meters we are getting N/A)...so:

(1.2 x 4) = MASS of 4.8kg...we now have 2 times the MASS of air, and that much more ability to make power.

Now that we have compressed it and the MASS entering the motor is 4.8kg, and it's occupying only half the space it did before (was 2m3, now it's 1m3), the density is twice what it was...but that's a byproduct of the formula....an effect, not a cause)

...

At least in my understanding of this...not being a physics major.

- Brian

EDIT: Spelling

[WDRacing]

Thanks for the headache jerk....

Its real simple fella's, add boost, get HP, nuff said...

[PapaSmurf2k3]

Ok, I dont know if this was said yet, cos i had to skip a bunch of posts because i have to go to class but i think most of you are forgetting 1 basic thing. A turbocharged motor produces more power (usually) at the same RPMs than a NA motor, and to quote motor trend "nothing eats fuel like RPMs" while this is all theory on my part, I do beleive friction is an exponential funcion. so... in conclusion with same A/F ratios and all that POOP, I think a turbo engine would be more efficient because its making more power at the same RPMs, therefore reducing the need to tach higher to obtain a faster acceleration, therefore lowering fuel consumption in order to accelerate to x speed. as far as consumption at constant speed, I beleive they should be just about the same, no matter what throttle opening (unless your drafting or something, which is reducing opposing forces, such as friction) ok now im late for class, i hope your all happy. rock on

[deezlins]

I wasnt saying that just increasing density will make power, I was saying that increasing density of the same volume will make more power, which is essentially increasing mass.