1600 Zetec SE Race Engine.

[Stu]

I admit, i did over react and close the thread, i'm not in a particularly good mood today.

 

I've calmed down and if you want to have this discussion, then by all means reply.

 

But lets start again. Why do you think, it can't produce more torque per litre than an F1 car? Also, how much torque does an F1 car produce? I thought it was a little over 200Lbft, perhaps i'm out of date on it as JAM says it's up to 270 now, so what do you believe it is?

 

Firstly, forget about total torque for the entire engine. When comparing, you should measure an engine's performance by specific output, be it power, torque, whatever, against a common unit. Typically in this context you will use the litre unit.

 

You claim your 1.6 engine has a specific torque output of 112.5 ft-lb per litre.

 

An F1 engine will have a specific torque output in the region of 100 ft-lb per litre.

 

This means that you are able to produce higher cylinder pressures than a Formula 1 engine, MEP's.

 

The reason I cite F1 as an example as this is a works level motorsport where every last bit of torque (and thus power) has to be extracted from the engine. It's a playing field where quarter of a foot-pound of torque makes a worthwhile difference. Even if an F1 engine produces at peak 270 ft-lb of torque, that's still the same specific output as your 'back garden' engine (not meant in a derogatory way, but relative).

 

Another example could be your typical 200bhp 2 litre n/a race engine. The highest you tend to see on these are around 165-170 ft-lb torque, which means a specific torque value of around 85 ft-lb/litre.

 

Or another example, the production FA20 engine by Subaru peaks at 151ft-lb and produces 200bhp at 7400 rpm. STO of 75.5.

 

The bottom line is your specific torque output can only go so high. It is ultimately limited by the swept volume of the cylinder. The ability to fill this chamber with air/fuel mixture is called volumetric efficiency. You can only go above 100% VE with either forced induction or with some resonance properties (like heim-holtz), however this only tips you over the edge and at one flow rate/engine speed. An engine produces MEP's (torque) based on how much fuel it can burn in one event. To burn fuel you need oxygen. There's only so much oxygen you can fit into the cylinder at atmospheric pressure.

 

If you use 100% VE as the theoretical max at atmospheric pressure then you may start to see why having a STO which is 30-50% greater than other race engines, and even works level engines, looks a bit ridiculous.

 

 

Now, don't take me the wrong way. I am not suggesting that this particular engine does not perform or that anyone is trying to fudge the figures. What I am suggesting that it is highly improbable that the figures are accurate due to the above. This is most likely due to method used to try and measured the torque (and thus calculate power). I suspect it was done on a rolling road. Perhaps an inertia type one? Rolling roads are often inaccurate and the only true way to measure torque accurately is to use an engine dyno (of course, this also needs to be operated correctly). This gives you a controlled environment where you are measuring torque at the crank itself. There's no fudge factors which may affect the readings (beyond atmospherics for correction purposes).

 

Anyway, I digress. I only post in the hope that it urges you to look into these things at greater depth. I was just looking through my Bosch automotive handbook for a couple of relevant pages I could photo+post up for you but alas nothing too relevant here. I'll keep on looking though. Enjoy, and keep building!

[Ahmotorsport]

Right, a nice essay there (genuinely)

 

1600 engine has 178lbft - 178 / 16 gives us the torque per 100cc = 11.125 x 10 = 111.25lbft per litre.

F1 has 270lbft - 270 / 24 = 11.25 x 10 = 112.5lbft per litre.

 

So it isn't more but anyway lets move on.

 

F1 have done brilliantly getting that torque, when it peaks in the region of 15,000RPM

1600 would peak at around 5000RPM

 

Therefore the 1600 has three times longer to fill the cylinders with air. There is also more room to fill due to the bigger bore size and stroke.

 

As you say, MEP's are produced by how much fuel it can burn, if there's more of it, along with more air per cylinder, more torque is produced, no?

[minirotty]

Sorry pal, although yes, I have gotten more fond of you lol those figures of torque are miles out.

 

And as said, it's possibly down to the r/r used not you bull sh!tt!ng.

 

I've had years of experiance now with r/r's and the conclusion I have come to when having my engine mapped for L2, Harvey Gibbs/Jimbo will be doing it, on a dyno. They know their sh!t, and I will defi any one who questions my engines power out put after they map it.

 

Not often I agree, stick up for Stu as he does my nutt in also, but this time he's correct.

[Ahmotorsport]

Sorry pal, although yes, I have gotten more fond of you lol those figures of torque are miles out.

 

And as said, it's possibly down to the r/r used not you bull sh!tt!ng.

 

I've had years of experiance now with r/r's and the conclusion I have come to when having my engine mapped for L2, Harvey Gibbs/Jimbo will be doing it, on a dyno. They know their sh!t, and I will defi any one who questions my engines power out put after they map it.

 

Not often I agree, stick up for Stu as he does my nutt in also, but this time he's correct.

I don't doubt they're not absolutely spot Ball. It was done on Northampton Motorsport (i think that's the name) rolling road, i don't have any experience with them so i can't tell you if they're good or not.

 

Of course, it would be ideal to put it on the engine dyno and hopefully one day it will be.

 

Don't get me wrong, i don't believe RR's are 100% accurate, but i honestly, from previous Zetecs can say, that it wont be far out. The way i look at is, even if it's 20lbft out, it's still good going and those cams we have made just pull and pull, you can hear it when they scream past.

 

 

Anyway, figures aside, arguments aside. It did what we told him it would and that's sh1t on the Fiesta with a Zetec SE in the same championship (which is also heavily tuned and a good driver)

Edited November 19, 2012 by Ahmotorsport

[Stu]

Harvey Gibbs/Jimbo will be doing it, on a dyno.

 

I wonder if i'm still the only person to have fallen asleep in Harvey's dyno (most likely much to Martin Hadland's surprise, as it was his engine being mapped!).. Ha ha

[scottybo]

regardless of the whole f1 argument i would say those are still really really good figures and i bet it goes link stink