I was thinking about the DSM Quiz idea I had a while back so newbs could graduate beyond the rookie level We'll I wrote a script based on a spreadsheet I have been using for a while so I could easily send it to friends for them to use since some people have a fear of spreadsheets. Anyhow, I thought I would throw it out there for you guys to take a look at and see if it is something that you would be interested in for the site. Sections could help people with some questions they may have regarding power potential, tire size, etc. There are tons of sections that could be added such as 'Effective Weight of Rotating Mass,' 'ET potential from Power,' etc. Many of the variables are automatically loaded for those who may not know their intercooler pressure drop, and changeable for those who do.Latest Update: I have added several sections for conversions/calculations in displacement. There are now OVER 12 functions including the power estimator and compressor map tool as two separate functions.Here's what it looks like thus far, color is changeable.

<table border='1' bordercolor='black' bgcolor='white' width='600'><tr><td align='center'><b><font color="red"><a name="n">Navigation</a><tr><td align='center'>Use these links to navigate the calculators.</td></tr><tr><td ><a href="#1st">1. Compressor Map Tool / Horsepower Potential Estimator</a></td><tr><td><a href="#2">2. Intake Temperature Calculator</a></td></tr><tr><td ><a href="#3">3. Airflow Converter (lb/min to CFM)</a></td></tr><tr><td><a href="#4">4. Airflow Converter (CFM to lb/min)</a></td><tr><td ><a href="#5">5. Injector Size Calculator</a></td></tr><tr><td ><a href="#6">6. Power from Trap Speed Estimator</a></td></tr><tr><td ><a href="#7">7. 1/4 mile ET and Trap Speed from Power Estimator</a></td><tr><td ><a href="#8">8. Engine Displacement Calculator</a></td><tr><td ><a href="#9">9. Engine Displacement Converter (cc to ci)</a></td></tr><tr><td ><a href="#12">10. Engine Displacement Converter (ci to cc)</a></td></tr><tr><td ><a href="#11">11. Tire Diameter Calculator</a></td></tr><tr><td ><a href="#12">12. Rotational Mass Equivalency Calculator</a></td></tr></table><form name='f1'><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='3' ><b><font color='red'><center><a name="1st">Turbo Power Estimator and Compressor Map Tool</a></td></tr><tr><td colspan='3' >This calculator uses the amount of air and fuel flowed and calculates the amount of horsepower created by burning that air/fuel mixture.</td></tr><tr><td colspan='2' width="500"><center><font color='red'>Variable</b></center></td><td width="100"><center><font color='red'>Input</b></center></td><tr><td width='500' colspan='2'>Engine Displacement (cubic inches)</td><td width='100'><center><input type='text' size='6' name='displacement' value="122"></center></td><tr><td colspan='2' >Desired Boost (psi)</td><td align='center'><input type='text' size='6' name='boost' value="10"></td><tr><td colspan='2'>Desired Engine RPM (redline or shift point)</td><td align='center'><input type='text' size='6' name='RPM' value="6500"></td><tr><td colspan='2'>Intake Temperature (Post Intercooler if applicable; &deg;F)</td><td align='center'><input type='text' name='temp' size='6' value="130"></td><tr><td colspan='2'>Intercooler Pressure Drop (psi)</td><td align='center'><input type='text' name='presdrop' size='6' value="1.5"></td><tr><td colspan='2'>Air Fuel Ratio</td><td align='center'><input type='text' name='tune' size='3' value="10.5"><font color='red'> :1</td><tr><td colspan='2'>Volumetric Efficiency (est. 90% for DOHC 4 valves per cylinder)</td><td align='center'><input type='text' name='VE' size='3' value="90"><font color='red'> %</td><tr><td colspan='2'>Brake Specific Fuel Consumption (BSFC)</td><td align='center'><input type='text' size='6' name='BSFC' value=".6"></td><tr><td colspan='2' align='center' width='500'><input type='button' value="Estimate Horsepower Potential" onClick="go()"></td><td align='center'><input type='text' size='6' name='power'></td><tr><td colspan='3'>Using the following two numbers given from the calculator above, you should be able to use a compressor map to select the turbo that best fits your desired power goals.</td><tr><td width='380'>Variables for Compressor Maps:</td><td width='120'><center>CMf: <input type='text' size='9' name='CMf'></td><td width='100'><center>Pr: <input type='text' size='6' name='Pr'></td></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2' align='center'><font color='red'><b><a name='2'>Intake Temperature Calculator</a></td></tr><tr><td colspan='2'>This calculator will calculate the intake temperature based on the compressor and intercooler.</td></tr><tr><td align='center' width='500'><font color='red'>Variable</td><td align='center'>Input</td><tr><td width='500'>Turbo Inlet Temperature (Consider inlet pipe and filter location)</td><td width='100'><input type='text' size='12' name='compintemp' value="100"></td><tr><td>Turbo Inlet Pressure (psi: filtered:~13.95; open:~14.7; -0.5psi/1000ft elev.)</td><td><input type='text' size='12' name='compinpress' value="14.5"></td><tr><td>Boost (psi)</td><td><input type='text' size='12' name='compoutpress' value="16"></td><tr><td>Compressor Efficiency (Map Pr and CMf on compressor map)</td><td><input type='text' size='12' name='compeff' value="70"></td><tr><td>Intercooler Efficiency (%)</td><td><input type='text' size='12' name='inceff' value="80"></td><tr><td>Intercooler Pressure Drop (psi)</td><td><input type='text' size='12' name='incpresdrop' value="1"></td><tr><td>Ambient Temperature (outside the engine bay &deg;F)</td><td><input type='text' size='12' name='ambtemp' value="80"></td><tr><td align='center'><input type='button' value='Calculate Intake Temperature' onClick='go10()'></td><td align='center'>----------</td><tr><td>Intercooler Inlet Temperature</td><td><input type='text' size='12' name='incintemp'></td><tr><td>Intercooler Outlet/Intake Temperaturev</td><td><input type='text' size='12' name='intemp'></td></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2' align='center'><font color='red'><b><a name='3'>Airflow Convertor (lb/min to CFM)</a></td></tr><tr><td colspan='2'>This calculator will convert airflow rates from pounds per min to cubic feet per minute.</td></tr><tr><td align='center' width='500'><font color='red'>Variable<td align='center'>Input</td></tr><tr><td>Airflow (lb/min)<td align='center'><input type='text' size='12' name='lbmin11' value='22.17'></td></tr><tr><td align='center'><input type='button' value='Convert to CFM' onClick='go11()'><td align='center'><input type='text' size='12' name='cfm11'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2' align='center'><font color='red'><b><a name='4'>Airflow Convertor (CFM to lb/min)</a></td></tr><tr><td colspan='2'>This calculator will convert airflow rates from cubic feet per minute to pounds per minute.</td></tr><tr><td align='center' width='500'><font color='red'>Variable<td align='center'>Input</td></tr><tr><td>Airflow (lb/min)<td align='center'><input type='text' size='12' name='cfm12' value='293.25'></td></tr><tr><td align='center'><input type='button' value='Convert to CFM' onClick='go12()'><td align='center'><input type='text' size='12' name='lbmin12'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='3'><center><font color='red'><b><a name="5">Injector Size Calculator</a></td></tr><tr><td colspan='3'>This calculator will allow you to calculate the needed injector size for you to support a specified horsepower at the injector duty cycle.</td></tr><tr><td colspan='2'><center><font color='red'>Variable<td width='100'><center><font color='red'>Input<tr><td colspan='2'>Engine Horsepower<td><center><input type='text' name='power5' size='12' value='210'></td></tr><tr><td colspan='2'>Number of Injectors<td><center><select name='numbercylinders'> <option value="4">4 <option value="6">6 <option value="8">8 <option value="10">10 <option value="12">12 </select></td></tr><tr><td colspan='2'>BSFC<td><center><input type='text' name='BSFC5' size='12' value='.6'></td></tr><tr><td colspan='2'>Injector Duty Cycle<td><center><input type='text' name='IDC' size='12' value='.8'></td></tr><tr><td width='380'><center><input type='button' value='Calculate Injector Size' onClick="go5()"></td><td width='120'><center><input type='text' name='flow1' size='5'> Lb/Hr</td><td width='100' align='center'><input type='text' name='flow2' size='5'> cc/min</td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='3'><center><b><font color='red'><a name='6'>Estimate Power from 1/4 mile Trap Speed</a></td></tr><tr><td colspan='3'>This calculator uses a modified version of Force=Mass*Acceleration to calculate how much power it would take to make your car go a certain speed by the end of a quarter mile.</td></tr><tr><td colspan='2'><center><font color='red'>Variable</b></center></td><td><center><font color='red'>Input</b></center></td></tr><tr><td colspan='2'>Vehicle Weight (Including driver)</td><td align='center'><input type='text' size='12' name='weight' value='3300'></td></tr><tr><td colspan='2'>1/4 mile MPH</td><td align='center'><input type='text' size='12' name='trap' value='88' ></td></tr><tr><td colspan='3'>Select Drivetrain: &nbsp;&nbsp;<input type='radio' name='drivetype' value='20' checked>AWD<input type='radio' name='drivetype' value='12'>FWD</center></td></tr><tr><td><center><input type='button' value="Estimate Power from MPH" onClick="go2()"><td align='center'><input type='text' size='12' name='wheelpower2'></td><td align='center'><input type='text' size='12' name='power2'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='3'><center><b><font color='red'><a name='7'>Estimate ET and Trap Speed from Horsepower</a></td></tr><tr><td colspan='3'>This calculator uses a modified version of Force=Mass*Acceleration to calculate how fast a car with the given power and weight would take to lay waste to a quarter mile.</td></tr><tr><td colspan='2'><center><font color='red'>Variable</b></center></td><td><center><font color='red'>Input</b></center></td></tr><tr><td colspan='2'>Vehicle Weight (Including driver)</td><td align='center'><input type='text' size='12' name='weight3' value='3300'></td></tr><tr><td colspan='2'>Wheel Horsepower<td align='center'><input type='text' size='12' name='power3' value='175.51'></td></tr><tr><td><center><input type='button' value="Estimate 1/4 mile from Power" onClick="go6()"></td><td align='center'><input type='text' size='12' name='ET'><b> @</td><td align='center'><input type='text' size='12' name='trap2'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2'><center><font color='red'><b><a name='8'>Engine Displacement Calculator</a></td></tr><tr><td colspan='2'>This calculator will determine the displacement in cc's of an engine based on the bore, stroke, and number of cylinders.</td></tr><tr><td width='500'><center><font color='red'>Variable<td><center><font color='red'>Input</td></tr><tr><td>Bore (mm)<td><center><input type='text' name='bore' value='85' size='12'></center></td></tr><tr><td>Stroke (mm)<td align='center'><input type='text' name='stroke' value='88' size='12'></td></tr><tr><td>Number of Cylinders<td><center><select name='NOC'> <option value="4">4 <option value="6">6 <option value="8">8 <option value="10">10 <option value="12">12 </select></td></tr><tr><td align='center'><input type='button' value='Calculate Displacement (cc)' onClick='go7()'><td align='center'><input type='text' name='displacement1' size='12'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2'><center><font color='red'><b><a name='9'>Engine Displacement Converter (cc to ci)</a></td></tr><tr><td colspan='2'>This calculator will convert cubic centimeters to cubic inches.</td></tr><tr><td width="500"><center><font color='red'>Variable<td><center><font color='red'>Input</td></tr><tr><td>Displacement (cc)<td align='center'><input type='text' name='displacement8' value='1997.42' size='12'></td></tr><tr><td align='center'><input type='button' value='Convert to Cubic Inches' onClick='go8()'></td><td align='center'><input type='text' name='convert1' size='12'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2'><center><font color='red'><b><a name=10>Engine Displacement Converter (ci to cc)</a></td></tr><tr><td colspan='2'>This calculator will convert cubic inches to cubic centimeters.</td></tr><tr><td width='500'><center><font color='red'>Variable<td><center><font color='red'>Input</td></tr><tr><td>Displacement (ci)<td align='center'><input type='text' name='displacement9' value='121.88' size='12'><tr><td align='center'><input type='button' value='Convert to Cubic Centemeters' onClick='go9()'></td><td align='center'><input type='text' name='convert2' size='12'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='2'><center><b><font color='red'><a name="11">Tire Diameter Calculator</a></td></tr><tr><td colspan='2'>A tire with a larger diameter will make your speedometer read slower than you are going and a tire with a smaller diameter will make your speedometer read faster than you are going. In addition, a tire with a larger diameter will take more power to rotate.</td></tr><tr><td><center><font color='red'>Variable</b></center></td><td><center><font color='red'>Input</b></center></td></tr><tr><td>Tire size example: 215/55/17<td><center><input type='text' size='1' name="tirewidth" textalign='center' maxlength='3' value='215'><input type='text' size='1' maxlength='2' name='aspectratio' value='50'><input type='text' size='1' maxlength='2' name='wheelsize' value='17'></td></tr><tr><td><center><input type='button' value='Calculate Tire Diameter' onClick=go3()><td><center><input type='text' size='12' name='diam'></td></tr></table><a href="#n">Back to Navigation</a><br>

<table border='1' bordercolor='black' text='black' bgcolor='white' width='600'><tr><td colspan='3'><center><b><font color='red'><a name='12'>Equivalent Mass of a Rotating Object Calculator</a></td></tr><tr><td colspan='3'>This calculator will calculate the affect of taking weight off the engines rotating assembly as multiplied through the gears. This includes flywheels, pulleys, etc. prior to the transmission.</td></tr><tr><td colspan='2' width='500'><center><font color='red'>Variable</b></center></td><td width='100'><center><font color='red'>Input</b></center></td></tr><tr><td colspan='2'>Change in rotating mass<td><center><input type='text'name='mass' size='12' value='10'></td></tr><tr><td colspan='2'>Diameter of rotating object<td><center><input type='text'name='radius' size='12' value='5.5'></td></tr><tr><td width='300'>Weight equivalency in first:</td><td align='right' width='200'>First Gear <input type='text' size='3' name='first' value='3.083'> :1</td><td><center><input type='text' size='12' name='firstout'></td></tr><tr><td>Weight equivalency in second:</td><td align='right'>Second Gear <input type='text' size='3' name='second' value='1.684'> :1</td><td><center><input type='text' size='12' name='secondout'></td></tr><tr><td>Weight equivalency in third:</td><td align='right'>Third Gear <input type='text' size='3' name='third' value='1.115'> :1</td><td><center><input type='text' size='12' name='thirdout'></td></tr><tr><td>Weight equivalency in fourth:</td><td align='right'>Fourth Gear <input type='text' size='3' name='fourth' value='.833'> :1</td><td><center><input type='text' size='12' name='fourthout'></td></tr><tr><td>Weight equivalency in fifth:</td><td align='right'>Fifth Gear <input type='text' size='3' name='fifth' value='.666'> :1</td><td><center><input type='text' size='12' name='fifthout'></td></tr><tr><td>Final Drive ratio</td><td align='right'>Final Drive <input type='text' size='3' name='final' value='4.848'> :1</td><td><center>----------</td></tr><tr><td>Tire Diameter (Use calculator if needed)</td><td align='right'><input type='text' size='5' name='tirediam2' value='25.46'> inches &nbsp;&nbsp;&nbsp;</td><td><center>----------<tr><td colspan='2'><center><input type='button' value='Calculate Mass Equivelence' onclick='go4()'></td><td><center>----------</td></tr></table>

As for the script, well you can download it in the .doc file found later on in the thread, paste the text into notepad, save as .html and play with the fully functioning version.

Are you an expert in Fortran or C++ or some other program language?

dyno_detour said:

Are you an expert in Fortran or C++ or some other program language?

Click to expand...

I'm not sure if you are being sarcastic, but nope, I have a 4 year in MIS from the University of Houston and was just screwing around and thought this might be a useful tool for my fellow members. What do you think?

I get an error ont his end, but this would be a very nice tool. I wouldn't mind tinkering around with it.

destruckeclipse said:

I get an error ont his end, but this would be a very nice tool. I wouldn't mind tinkering around with it.

Click to expand...

It won't work on this page because the script can't run. Did you save the word document and copy the text to notepad and save as a .html file? Again, it won't work inside a post.

I've updated the original input screen to accommodate the new scripts which you can see in the original post, and I provided the changes in the script that you can download below that for the working versions. If there are any suggestions as to what calculations we could add, please run these by me and I'll see what I can do.

How is this going to be accurate without taking airflow into consideration? Ve is going to be near or over 100% for boosted applicationsat peak efficiency. There is more pressure drop from most intercooler pipes than the intercooler itself, you might want to add that in there as well.

GVR4592 said:

How is this going to be accurate without taking airflow into consideration?

Click to expand...

I'm not sure where you got that the first calculator doesn't take flow into consideration but that IS what the calculator does, calculates the flow of the system (read Corrected Mass Flow a.k.a. CMf)

GVR4592 said:

Ve is going to be near or over 100% for boosted applicationsat peak efficiency.

Click to expand...

Nope. You will still not see 100% cylinder fill, but what you do fill the cylinder with is pressurized, which is taken into consideration with the CMf calculation.

GVR4592 said:

There is more pressure drop from most intercooler pipes than the intercooler itself, you might want to add that in there as well.

Click to expand...

Nobody takes that into consideration, but you can calculate the volume of your pipes, use the universal gas law and figure it out if you want and add it to the intercooler pressure drop. Better yet, measure the pressure in the compressor and at the throttle body and you will know your custom pressure drop. Simply using intercooler pressure drop is more than accurate enough is what I'm getting at. If it's not sufficient for you, I would add what I thought appropriate for my pipe setup.

Hope this clears things up for you.

Maybe you can explain to me how it determines flow, I guess I don't get it. Wouldn't you need to take into account the amount of air entering the engine, not just the pressure of the air?

I wasn't referring to the volume of the pipes and the time it takes to pressureize them I was referring to the roughly .3 psi pressure loss for every 90 degree bend in intercooler pipes. That would add up very quick with most setups. More than the average 1.5 psi for an intercooler alone.

According to every book I have read on the subject and the makers of dsmlink, a forced induction engine can achieve 100% ve. N/A engines can go over 110% VE. Can you explain how a boosted engine can't?

GVR4592 said:

Maybe you can explain to me how it determines flow, I guess I don't get it. Wouldn't you need to take into account the amount of air entering the engine, not just the pressure of the air?

I wasn't referring to the volume of the pipes and the time it takes to pressureize them I was referring to the roughly .3 psi pressure loss for every 90 degree bend in intercooler pipes. That would add up very quick with most setups. More than the average 1.5 psi for an intercooler alone.

According to every book I have read on the subject and the makers of dsmlink, a forced induction engine can achieve 100% ve. N/A engines can go over 110% VE. Can you explain how a boosted engine can't?

Click to expand...

Okay:cracks knuckles:
Pr=(Boost+Atmospheric Pressure+Pressure Drop)/Atmospheric Pressure

Di=(Boost Pressure+Atmospheric Pressure)/(R*12*(460+Intake Temperature)

Mf=Di*Displacement*(RPM/2)*Voumetric Efficiency

CMf=Mf*((sqrt(Compressor Inlet Temp/545))/(Atmospheric Pressure/Corrected Compressor Inlet Pressure)

Horsepower Estimate= (CMf*60)/(A:F*BSFC)

I'm not sure how you missed it, but now you can clearly see that the estimation takes the airflow into consideration, which is based on how big the engine is, the density of that air, the rpm of the engine, and the VE.

The whole reason I left the fields changeable is for people like you who wish to change them. It is the only way to make everyone happy (you're welcome). I could have just used preset numbers and asked for the boost and assumed 2.0L for displacement, but I know that this could prove useful to people with more than the average users knowledge of such things. Beyond that, the first calculator may only estimate horsepower, but it is perfect in helping choose a compressor wheel. Have you tried the working script?

So is this supposed to be able to calculate horsepower for any application?

GVR4592 said:

So is this supposed to be able to calculate horsepower for any application?

Click to expand...

Yes. I plugged in the numbers for my sisters Lancer OZ (heh, it's yellow) and it came out right . Inputs: 2.0L, 0 boost, 0 pressure drop, .45 BSCF and .9 VE came to 163 hp potential. That makes total sense assuming you would actually see atmospheric pressure in the manifold. I'm going to say that after some reading, it would not be unjustified to assume a greater VE, perhaps calculating the pressure ratio and using that as a percentage, but that has to be looked into further.

Yes the entire calculation allows you any configuration. It would also be helpful with my latest addition (fuel injector selector) since you will now be able to have this conversation with yourself:

[Injected Theater presents: Crazy Newb's Converstion with Himself]
Person inside head #1: "Hey Steve, I want a 2.4L 500 hp street monster on pump gas, what turbo should I use?"
Person inside head #2: "Well who doesn't, Bob? Well plug in the numbers and figure it out, you idiot!"
Bob: "Okay, okay! SHEESH, you don't have to yell. It's close quarters inside this head and plus, it echoes."
Steve: "Alright, I'm sorry, Let's figure this out. For displacement we need 2.4L in cubic inches, put that in."
[I'm going to add this calculator into the mix in a bit, don't get your panties in a wad!]
Bob: "Ah, 148 cubic inches. How much boost should I put in?"
Steve: "Well we get 93 octane at the pump, so 22 psi on a good tune would be alright, it's been done."
Bob: "Alright, I'm not sure about all of these other numbers but I've heard we can put at least 100 for VE on a boosted application."
Steve: "Okay, well then do that, say 110%...What did we get?"
Bob: "465."
Steve: "What? That seems a bit low! Aren't we going to upgrade the valve train and rev it higher? Change the RPM to 7500 and see what that gives you."
Bob: "Alright..."
Steve: "Well.."
Bob: " 'Well' what?"
Steve: "What does it say now?"
Bob: "Oh, sorry. It now says 537 hp"
Steve: "Now that's more like it! Let's pick a turbo"
Bob: "How do we do that?"
Steve: "Use those two numbers Pr and CMf and compare them to the compressor maps you can find online."
Bob: "Okay, looks like the GT35R is a pretty good match, we'll go with that. What size injectors should we run?"
Steve: "How am I supposed to know? Put 537 hp in the calculator."
Bob: "Good idea."
Steve: "Well..."
Bob: "Oh, yeah, it says 1057 cc/min"
Steve: "Dang, that's a big injector! Crap, here comes Larry!"
Person inside head #3 "What's up guys?!?
Bob: "Hey Larry!"
Steve unenthusiastically: "Hi, Larry. Well, that's my que. I'm leaving." Exits.
Larry: "What's going on with Steve?"
Bob: "He's got some crazy idea that when you and me get together there's a strong chance the world will end and he doesn't want to be associated with it in any way. We were planning a 500hp DSM build!"
Larry: "WOW! That sounds like it would be fast! How fast would that go in the ¼?"
Bob: "I don't know, let me tinker with this calculator and see what I can get." Tinkers. "Well it says 11.21 @ 120.1 in a 3300lb car with 537 hp."
Larry: "HOLY CRAP!"
[Curtain]

I just finished The injector section, but haven't had time to update the code. I'm also working on the ET from Power calculations and a few others, but I'll probably hold off for a while.

Nice work, but theoretical physics and real life are sadly quite different The HP calculator using ET trap is pretty far off, it shouldn't take 650 hp to get a average weight 2g GSX to 125 mph at the end of the 1/4.

I think what you have done is fantastic and a very useful tool.
Persoanlly I don't care if its not 100% accurate. It's better than guessing and its certainly better than anything else anyone else has ever done.
Good job!

Injected, in your opinion what's an average Ve for a boosted 4g63?

eclipsegsx1736 said:

Nice work, but theoretical physics and real life are sadly quite different The HP calculator using ET trap is pretty far off, it shouldn't take 650 hp to get a average weight 2g GSX to 125 mph at the end of the 1/4.

Click to expand...

I ran your numbers and it was 605, not 650 accroding to the formula. I'll be the first to say that the HP estimate and the 1/4 MPH to HP estimate are just that: ESTIMATES. I can also tweak the formulas. However, if you look at the 1/4 mile times section, a 120mph pass is a very low 11 second pass, and I doubt that those cars were full weight. I ran the script and it says that a lightened DSM (3100 lbs) would take 567 hp to move down the quarter. Makes quite a bit of sense.

PieEyedPiper said:

I think what you have done is fantastic and a very useful tool.
Persoanlly I don't care if its not 100% accurate. It's better than guessing and its certainly better than anything else anyone else has ever done.
Good job!

Click to expand...

First, I want to say thanks. I'm not doing this for me, I'm doing it to help the DSM community. What you said is basically the idea. Some of the calculations are estimates and some are HARD calculations (such as Pr, CMF, Tire Diameter, Injector sizing and Equivalent Mass).

GVR4592 said:

Injected, in your opinion what's an average Ve for a boosted 4g63?

Click to expand...

I'm glad people are taking interest.

GVR4592, though I am not a member, it is still a good idea to look in other places for information sometimes:

http://www.dsmtalk.com/forums/showthread.php?t=16581

Read especially about the part where you are filling 90.5% of the cylinder with pressurized air. From that idea, imagine the pressure drop in the cylinder when the air expands to fill the additional 9.5% of the cylinder. Eh, maybe we should start a thread here (DSMtuners) about VE.

So 90%?

GVR4592 said:

So 90%?

Click to expand...

At what RPM? and are we talking about the 1G, 2G? Headwork will make a big difference. I guess the best answer I can give is to read through the post I gave you and run the calculations there the best you can, or I can turn that into a calculator as well , but I won't right now.

Take a 1g 2.0 engine, completely stock engine, stock intake manifold, stock exhaust manifold. Assume 90% ve, input 30 psi, 7500 rpms, and leave everything else alone because they are fairly accurate assumptions. Am I missing some other important variables? What hp do you come up with

GVR4592 said:

Take a 1g 2.0 engine, completely stock engine, stock intake manifold, stock exhaust manifold. Assume 90% ve, input 30 psi, 7500 rpms, and leave everything else alone because they are fairly accurate assumptions. Am I missing some other important variables? What hp do you come up with

Click to expand...

441HP using the working script. 30 psi is high and so is 7500 on a stock valvetrain. Not something I would do without race-gas. You can try downloading the working script and playing around with that.

Ok so how would I account for a larger turbo?

GVR4592 said:

Ok so how would I account for a larger turbo?

Click to expand...

What do you mean?

Well if you input 30 psi, 7500 rpms and 90% ve, you get 441hp well that's great for a 16g but what if you have a 35R or something bigger. How do you get accurate numbers for a larger turbo?

GVR4592 said:

Well if you input 30 psi, 7500 rpms and 90% ve, you get 441hp well that's great for a 16g but what if you have a 35R or something bigger. How do you get accurate numbers for a larger turbo?

Click to expand...

???

30 psi is 30 psi. The difference would be in compressor efficiency. A larger turbo will move the same amount of air, but it will be more efficient, resulting in lower intake temperatures.