So from reading this thread I am gathering that most here think the dip is caused from the injection and intake system along with tuning.

What about all of the people that say it is the headers? Do the headers not really have anything to do with the torque dip?

They made the most out of what they had to work with.. Everything is a compromise..

Plenty of other 2L 4 bangers out there with more linear tq curves.. Just trying to understand why the FA20 has a hole..

There aren't too many 2L's banging out at least 200HP though. The ones that come to mind are the Acura RSX-S and the AP1 Honda S2000- VTEC sure is nice.

it wouldn't be a hole if you rev it out. Problem solved, idk why people are making these threads.

I'm not the one complaining about driving this car or the characteristics of the torque dip.. but there is no denying the fact that it exists..
nothing wrong with wanting to know why or trying to "fix" it..

I haven't seen anything about the intake casuing it. Its been a combo of tune plus a good header, but nothing by itself. My tune alone helped, but it was still there. Then adding the header helped even more, but it was still there. Once the tune was readjusted for the header, problem solved. It may have to do with cam and ignition timing with the header.

Here is an example of a good equal length header and a tune...
http://i972.photobucket.com/albums/a...pseec669fd.png

That's quite impressive. What header?

Nicely done. I hope to meet up with you sometime, I would consider doing what you did. I am not looking for 300whp for a daily driver, this looks just about perfect.

This is the Nameless long tube header with 3" exhaust. This particular header is not out yet...but just showing an example of what the right header and tune can do.

That would be great! This isnt my exact set up thought. This header is not in production yet, but soon. I am running an equal length header and tune, the torque in the dip area feels pretty flat. This is the only dyno I have with the header and tune, but keep in mind, this was just slapping the header on. It has now been tweaked much more...I have yet to dyno it with the new tune.

http://i972.photobucket.com/albums/a...ps17208996.jpg

Well, in stock ECU there is a clear change in AFR and injection table, so there are 2 torque dip, one is caused by engine's component and geometry, the other is caused by ECU limitation, that's why changing parts and ROM makes the car rev much better.

And if you just check fluid dynamics parameters you can see that the stock car can't breath.

Toyobaru did a great engine and perfectly hit their commercial target! This is the funniest car ever with a 2.0 L NA engine!!

Besides it earns a lot of hp every time you look at it lol

Hello. Since december 2011 i'm interesting by the new Hachi roku. You can't have port injection and direct injection between 3000 and 5000 rpm because the motor would overheat. I've seen a PDF from Toyota and it is said that the motor turn not enough quickly to refresh the combustion chamber. After 5000 rpm it turns very quickly and the exhaust valve open quickly to absorbe the heat. I research the pdf file see you soon! I think the D-4s system needs Toyota ingineers to be updated with Ecutek. The complexity from the system whith back pressure and injector heating is to complex for tuners. Toyota says that the injector could be damage by using DI and PI in the same time. The ijectors could reach 150°C and overheat.