I am concerned with finding the truth. Seriously. ray sir 6 says the "experts at Garrett" should be right, so I used their formulas that he can't seem to figure out how to use. The I win part is just me being cocky because he was being cocky in 4 or 5 post in a row where he uses his incorrect numbers. (see the funny pic thing of the dude shaking his head at me like I just got pwned while his very post he put that in contains multiple errors?)

I mean seriously, why would you add .012 to BSFC because a motor is 12% less efficient? That makes no sense at all now does it? Yet he did it.

He tried to prove me wrong with the formulas and I pointed out he calculated the BSFC wrong. More than once. Finally, he then got the wrong delta P to support his argument. I pointed that out as well. He "corrects it", but it's still wrong. I suggested multiple times his math was wrong, specifically the BSFC and he should correct it and his numbers would come out right. He couldn't figure that out. So I showed him how to do it. While I was at it, I went ahead and did the fancy formulas he used to "prove me wrong" so he wouldn't get confused again trying to use them.

 

Pssst! The Wisecos are 200grams lighter per piston. Hello quicker spool from less rotating mass.

 

That's the same as a slightly lighter flywheel.
You won't feel it much outside of neutral, or at most, 1st gear.

 

I emailed Dema Elgin if he thought higher c/r results in higher VE due to better evacuation of exhaust gas at the top of the exhaust stroke. He replied that he's on holiday and I can call him in 3 weeks.

 

And since I was playing with Garrett's "correct" formula, I took the liberty to rearange the variables such that we could solve for HP given the other parameters. Furthermore, I asked myself "what effect would changing MAP have on HP". So I setup two equations and solved them. Turns out it's a direct relationship. Therefore 30% more MAP = 30% more HP. (jc rotor didn't believe this earlier)

 

enginerds.jpg

 

Good. And I am glad you got my point. Any person who cannot entertain the idea that they are wrong, is.


To be flat-out honest (notice the automotive pun), I did not either of your posts one the math became the means of 'if-then', mostly because it is still based on some presuppostions... I think omaharam said it best; this is a situation where the true test is on the road, not on the notepad. I'll grant you, my inclination is led by my gut and that is mostly all, but...


I am just glad most of you guys allow possibilities that don't fit into your world-view, unlike most of those sanctimonious ****** on thecarlounge.com.

 

So a lighter flywheel is a waste of money. Well lets chalk that one up as fact.

 

*goes to basement to get Heywood*

will report back if I find anything conclusive.

 

You win if you consider proving me right winning.

You just proved that a LC motor takes more boost to make the same power as a HC motor.

And you didn't follow the allowed BSFC area, which was .5 being the best, and .6 being the worst. You can't use a number less than .5, so using .446. It has to be 5 or higher. So you just input an incorrect value into the formula. Read and follow directions much?

The difference will get larger as the hp increases.

And the .012 was based on 12% of .1, since the available area for the BSFC was between .5 and .6, so what is 12% of .1? Careful, the answer might shock you. If you want to see the math, put .1 into the calc, and multiply by .12, and you'll get .012, amazing what a little math can do when you apply it CORRECTLY.

Now using your math, BSFC = (mass of fuel/unit time) divided by (Power), with my motor making 100hp, that would mean your LC motor would make 88hp (12% rule again). So what is 88/50? .568, so let's plug that number in there.

Care to try your formula again using the correct data?

HP = 218 flywheel hp
A/F = 11
BSFC = .568

Therefore WA = 22.7011lb/min



WA = 22.7011
R = 639.6
Tm = 106 (datalogged)
VE = .9652
Now the 12% rule also applies to the VE. The range for the VE on a 4-valve is .95-.99. That means the range is .04 points, so 12% of .04 is??? That's right, .0048. So we need to subtract .0048 from .97 (the higher compression, higher efficiency motor) which is .9652.
N = 7500
Vd = 97.632

You come up with 8218106.93496 divided by 353379.024.

That equals approx. 23.256, but you have to subract atmosphere, which is 14.7

So that equals 8.556 psi to make the same power.

So the math says I'm right again.

Thanks for showing me how to get the correct BSFC. It REALLY proved my point. Next time follow the minimum and maximum ranges before you try to do a calculation, it really helps. Those directions are there for a reason, not just to fill in empty space on the page.

Shall we continue the math battles or do you accept defeat?

We are only at a difference of 2.887psi right now, and that's a LOW POWER example. The difference gets bigger (funny thing about percentages) the more you compare higher hp cars.

Incase you didn't catch that one....

12% of 100 is 12, but 12% of 300 is 36. See how the percentage gets bigger?

 

Yes, and thank you for fixing my errors on the BSFC. Too bad you couldn't use your own formula correctly. .5 was the LOWEST ALLOWED BSFC, so you had to go UP from there to account for 12% less effeciency.

I learned something new today, and it really helped me out. Thanks.


Cause I was doing the simply math of adding 12% of .1, which is .512. Thanks for giving the appropriate BSFC formula so I could come up with the correct value of .588.

You never pointed out the VE error, I found that trying to find the error for the BSFC.

You ended up confusing yourself at the same time. Luckily I found your errors and corrected them.

 

Jeezus.

If BSFC of one motor is 0.6, then the BSFC of a motor with 12% higher efficiency will be:

0.6 / 1.12 = 0.536

All else being equal, power and torque are proportional to MAP.

 

I have been forced to resort to using the only method some people will listen to, MATH FORMULAS, to prove what is already known in the REAL WORLD.

He is normally pretty smart, but he has been disappointing me lately.

 

: magna:

I think you guys should let this go. Fighting about it is obviously not going to change the mind of either of you. Quite frankly I'm bored with it.

 

That is the same as the formula I used.

If my motor is .5, and it makes 100hp, then a car with 12% less efficiency will be have 88hp.

0.5/.88 = .568.

So it is correct BSFC.

 

 

It's actually fun to find little areas where we messed up in our calculations and fix them.

I'm well aware I am correct, I work in this field, Import Performance Shop for the win.

 

OMG you're STILL doing it wrong. I 100% give up trying to explain it to you. I give up. You surround yourself with whatever you want. I know what I'm doing. You don't just add decimals to BSFC. EVER WTF? Still wrong there buddy. And who said .5= "normal" and .6= 100% efficient? WRONG AS **** BUDDY. Look up BSFC for the 14th time. Hell, you just talked about your BS way of calulating BSFC, but then you used the correct method I just pointed out in your "argument". Good job.


EDIT: And I did point out your VE error in my 1st screen shot of math. See the *'s.

 

You mean AFTER I fixed my VE #?

.5 is most efficient, and .6 is least efficient. You seem to have gotten that completely wrong. No, .5 doesn't mean 100% efficient, it just means that is the highest available per the instructions for the formula. Again, you are missing the INSTRUCTIONS when you do the formula. The allowed range for the BSFC is .5-.6, so how do you have .4** in your formula? Are you gonna fix that or just keep insisting that the formula you gave me for determining BSFC is wrong?

 

Wow, you needed to use the formula to figure that out. Just like Jason C said, with all else being equal, MAP = HP, higher MAP, higher HP. But the formula only works if you use it right. A LC engine is LESS EFFICIENT than a HC motor. So you have to CHANGE (not the same) the variables that reflect the engine's efficiency, which are BSFC and VE. So now you have more than MAP changing in the formula.

Do we need to keep this going? I'm sure you are getting as tired of correcting my errors as I am of correcting yours. I have already quoted experts from several fields who work on turbocharged internal combustion engines, and they agree with what I have said, based on their REAL WORLD experience. Go call up an expert, like engineers at JE, or Garrett, or Turbonetics, and they'll tell you the same thing. You've dug this hole you are in, so you can either keep digging till you hit China or you can get some outside help to pull you out. Sadly that would mean admitting you were wrong, but hey, it happens sometimes. Just like I was wrong figuring for BSFC, and input higher VE numbers for the LC lower VE motor. Nothing to be ashamed of, it happens, but you just have to accept that it happens and move on.

Math, unless it is done wrong, will always represent real world results.