Engine Efficiency Numbers

[The Devils Own Chariot]

Im sure Im going to get a big slap on the hand for not searching enough. I have a buddy with a program that maps out the best turbo trim, size, and efficiency for any engine. He needs some engine volumetric efficiency numbers for a stock 4.3L turbo. Not really sure where to come up with that.

 

[turbodig]

Re: Engine Efficiency Numbers

Im sure Im going to get a big slap on the hand for not searching enough. I have a buddy with a program that maps out the best turbo trim, size, and efficiency for any engine. He needs some engine volumetric efficiency numbers for a stock 4.3L. Not really sure where to come up with that.

I don't know that I've ever seen any real numbers, just guesses. 350 numbers of that vintage would be comparable.

 

[Loeryder]

Re: Engine Efficiency Numbers

The turbo increases VE so are you looking for base VE numbers for a 4.3L with 8.5:1 CR?

Might be a tough number to find.

I am willing to be if you call comp cams tech support they can tell you.
VE is a mjor factor when you go to changing cams and rockers so a company that deals in those parts is gonna be your expert.
Please do report what you find because 15 minutes on google and I found nothing>
I would be interested in adding it to the specs page on sytyauthority.net

 

[turbodig]

Re: Engine Efficiency Numbers

The turbo increases VE so are you looking for base VE numbers for a 4.3L with 8.5:1 CR?

It really depends on what and how they calculate, to be sure. Some programs want the "artificial" VE, some want the actual.

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

Yeah it would be interesting to see what the numbers are for the engine. Also intersting to see what my buds program comes up with for a turbo.
Would GM have that sort of info deep in their archives?

 

[SY2455]

Re: Engine Efficiency Numbers

Try working with this.

http://www.ajdesigner.com/phpengine/engine_equations_volumetric_efficiency.php

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

Cool page. If only I had engine CFM.

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

This is what I came up with. I got the cubic feet per minute off this page.
http://www.hotrod.com/featuredvehicles/hrdp_0306_1992_gmc_typhoon/index.html
Does this look accurate for the most part. I assume when the calculations ask for engine cfm they want exaust manifold cfm.

Cubic feet per minute (CFM) 240
Cubic inch displacement (CID) 262
Revolutions per minute (RPM) 4500

Volumetric Efficiency (VE) = 0.703511450382

 

[SY2455]

Re: Engine Efficiency Numbers

If you read this VE is base on Air drawn into and not out of a engine.

This infor comes from: http://www.answers.com/topic/volumetric-efficiency

Sci-Tech Encyclopedia: Volumetric efficiency

In describing an engine or gas compressor, the ratio of volume of working substance actually admitted, measured at specified temperature and pressure, to the full piston displacement volume. For a liquid-fuel engine, such as a diesel engine, volumetric efficiency is the ratio of volume of air drawn into a cylinder to the piston displacement. For a gas-fuel engine, such as a gasoline engine with carburetor, throttle body, or port injection, volumetric efficiency is based on the charge of fuel and air drawn into the cylinder. See also Compressor; Engine.
Volumetric efficiency of naturally aspirated automobile and aircraft reciprocating engines may be 85–90% at rated speed. Supercharging or turbocharging increases volumetric efficiency, giving values over 100%. Air compressors, refrigerator compressors, and dry vacuum pumps are generally specified for a volumetric efficiency of 60–90%. See also Internal combustion engine; Reciprocating aircraft engine.

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

VE at 3500 rpm is 1.08879956545
Anyone have something esle for a stock motor?

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

Ok those numbers are not right. I need to figure out what the cfm is on a NA motor. cfm pulled into the motor that is.

 

[nallj92]

Re: Engine Efficiency Numbers

why dont you discuss this with a vendor who sizes turbos for goals/builds, theres lots of guys around here that know what works and what doesnt. I understand you would like to think outside the box, so if you figure it all out, more power to you.

btw still havent sent that out yet, its at my other residence now, hoping for next week.

 

[The Devils Own Chariot]

Re: Engine Efficiency Numbers

why dont you discuss this with a vendor who sizes turbos for goals/builds, theres lots of guys around here that know what works and what doesnt. I understand you would like to think outside the box, so if you figure it all out, more power to you.

btw still havent sent that out yet, its at my other residence now, hoping for next week.

Yeah no hurry. Thanks for doing that.
I was hoping someone would chime in with some numbers in the stock setup but it has not happened yet. I think this would be a good thread for someone that wants to upgrade their turbo but is worried about going to to big, what trim, and needing an expensive/exstensive tune. My buddy uses a program that will show a lot of net things based on volumetic efficiency.
I will keep digging around the internet for some numbers to calculate it.