slightly confused by your statement can u dumb it down slightly lol

 

What he's saying, basically is that power=airflow which is basically true, if you want to look at it strictly numerically. A bigger displacement will flow more air, at the same pressure, meaning more power, until the turbo becomes inefficient or the head can't keep up, and air can't flow into the cylinders fast enough. For real life usage (IE street use) that's kind of irrelevant, because an extra 500 RPM or so of spool is a huge deal, and the extra off-boost torque is super nice to have.
If all you wanted to do was drag race, or if you were cool with leaving every stop light at 8K RPM, there would be no difference between the 2.4 and the 2.0, but that's crazy. The 2.4 is a great street engine, because while it doesn't like to rev quite as high, thanks to the head, it loves to spool. I have spent some time daily driving a 2.4 LR and it's highly entertaining, it's also much easier to drive than a 2.0. I feel that the off-boost torque increase is not talked about enough, because it's awesome.

 

This should be in a brochure or something as based on this anyone would want to buy a 2.4LR.

 

And that's exactly what I want off boost grunt I drove my friends built sti and while ill admit I love my car his ta is highly addicting and it feels like he doesn't need to spool the Turbo to move so to speak as with me it feels like in never NOT in boost LOL...so I guess ill skip the bigger Turbo and just get a 2.4 then down the line a bigger turbo

 

One of the things that impressed me the most was the fact that I can drive my car normally and it feels like a really fast NA car (Think Modified S2K). I barely have to get into boost for it to haul. Between the higher compression and the displacement its fun to drive at any speed.

 

Yes, this^^^^

The one caveat to your statement, though it is technically included, is that on octane limited fuel you will make more power on a big motor than a smaller motor. The reason is as you describe its adjusted airflow, the bigger motor uses more CFM for the boost to back up in the intake manifold. This is why a proper 2.4 can make 580 at 23psi where the same power on a 2.0L would be 29psi on pump.

Yeah we can get them for you whenever. I am currently waiting on my next order to arrive though.

Aaron

 

So on 92 octane will you get more out of a 92mm, 94mm or a 100mm crank? My basic understanding of VE says to go with the higher rpm option.

Also, your dynograph of the 2.0l vs 2.4l shows the 2.0l dropping off at the same rpm as the 2.4l. This seems odd as you should be able to push the 2.0l farther into the higher rpm instead of stopping at the rpm of a stroker and should size the turbo accordingly.

 

The reason they drop off is camshaft and/or headflow related in this context. On 92 octane you will get more out of a 100mm than revving a shorter stroke higher UNLESS you have the camshafts/headflow/turbo to take advantage of it. On a given combo the 2.4 will rock the other options on octane limited fuel such as 92 octane.

Case in point-



This is what Batty and I are talking about. 29psi is about the limit for making good power on 92 octane. I have run more boost with out knock but not necessarily made more power.

Here is the 2.4 when I took it back out to 29psi-



Aaron

 

I love the bigger motor, I just wanted to be clear so people werent "upset" when they buy a 2.4L and arent making more peak power on a 16G. It will have a better powerband and better manners. I had a stock 14B on my Talon and the turbo could only hold 12psi of boost at 6K rpm. The engine was consuming the air so fast there was no resistance and the turbo couldnt keep up. The car hit 21psi and fell to 12 at 6K. Still it ran 12,6@110. I didnt realize it was falling off so bad and hadnt changed the under 15psi portion of the map from the big turbo map. It fell into a rich fuel and low timing area where I was setup to help the turbo spool past to min boost on the WG. Had I tuned that area of the map (AEM using SD) it would have run faster. I swear that car was like a 5.0L. Prob made 400tq and 320whp. It ripped at the touch of the throttle.

 

We think very much alike! Must be a short guy thing! I looked for you at the SO last summer and you were crashed in the trailer. We will meet up this summer.

 

Aaron, provided the cams and turbo are able to keep up, what kind of RPM does the 2.0L and the 2.4L start to run out of head flow on a mildly cleaned up EVO head?

 

2.4 so far really seems to be around 7800 based on my experience. The 3586 and 3794 with the S2xxx (not allowed to add R anymore) and my head make peak power around that where a 2.0L with the same setup seems to be more in the 8300-8400rpm range. I have a datapool to go though to get the best comparisons but I think typically there is a 600rpm difference between a street/strip port on a 2.0 and 2.4 with the same turbo or a full on banzai and the 2.0 and 2.4.

Batty,

I sleep alot. I will be up for the Shootout though I have made more on 2.4s with a 16G than a 2.0L for the most part though. The exception would be Luke's 522 which was a 2.0L.

Aaron

 

OK. I just need to make sure that I am following you correctly. Are you saying that with a nice head, you were able to extend the powerband 600 RPM?

 

lol no he's simply giving the difference in when the two motors start to gas out and there is a 600rpm difference between the 2.0 and 2.4

 

Wow i Gota get myself a 2.3 lol