Torque dip reasoning solved?
 

Hey guys and gals,

I was reading a some info on F1, and came across
this statement for a question that was asked by the writer.

Why would would you want to generate less torque in the mid revs
range?
"The trade-offs concern driveability (the response of the engine
to the driver requested torque), acceleration
(less torque = less acceleration, except if grip limited)
and fuel consumption. In general, reducing the torque is
achieved by igniting the fuel later in the cycle by means
of the ignition map. This may improve driveability smoothing
out the torque curve which may help the driver manage his tyres.
This is not in any way a forbidden driver aid or an attempt to
mimic the behaviour of a forbidden system (eg closed loop
traction control)" said Rob White, Renault Sport F1 deputy
managing director

these are my thoughts on the above.

1) If I were to hazard a guess, I would think that the engineers at
subaru or Toyota(not sure of which designed the software), pulled
timing as this statement would suggest to mitigate wheel spin,
considering that it will be using Michelin Primacy tires
that are LOW grip and narrow. So combining low grip tires and a torque
spike in the middle of the rev range could induce an overly tail
happy car that could potentially overwhelm the TC and VSC in wet
conditions-I've experienced this in stock form, pulling third on a
shitty B-road=scary! This makes me believe that the fun police at
these firms, wanted to tone this down to prevent any lawsuits,
considering that this car will be bought by mostly newbies
(young males or gals) that are new to RWD, and therefore inexperienced.
I used to have (sold it a month before) a 84 300ZX Turbo pushing 12 psi
, so I was used to the torque of that, so before flaming me
for being inexperienced, I just wanted to point that out.

2) they reduced the torque in order to "save" some for later models.

3) maybe the are also capping this engine, so that the STi model comes
out they will release a lot more power, as I'm sure the tires
and suspension will be better, to contain it.

I did a search function I didn't find anything that directly
states that the torque dip has been resolved, but only reduced. I thought
this was a very interesting statement and clearly by the article it
appears that Toyabaru have incorporated something along the same lines of
throttle pedal and engine mapping. In saying that, I am by no means an
automotive engineer or tuner, so I have learned all my info from race car
magazines and research.

This is the main page link:
http://www.auto123.com/en/news/f1-a-...-of-technical-articles-about-formula-1?artid=152064

This is the page that I pulled the above statement from:
http://www.auto123.com/en/news/f1-technique-explaining-engi
ne-torque-maps?artid=146245

whats everyone's thoughts?

Get a turbo. Issue resolved.

my AEM intake really helped w/ low rpm (sub 2k rpm) when daily driving. I have the AT and and the intake allows me to actually accelerate up hill in 6th around 2k rpm around 50mph w/o the car having to down shift. Still lacks torque between 3k-4500, but w/ oem instake it was 3k-5k rpm

I didn't think my car had any issues below 3000rpm... above that in the tq dip fuck its annoying.

I'm not sure the engine has enough power that the engineers would feel they needed to purposely add a torque dip in the mid range to make it safer. I think it's something more fundamental in the design - even the Vortech supercharger build with a custom tune has the dip (though not as pronounced).
It might just be the result of getting as much from a 2 L engine as they could within a given price range.

The components that affect power bands are cams, intake and exhaust manifolds and tuning. I'd put my money on the intake manifold, namely runner length, being to blame seeing as most other things have been tried. That won't be an easy fix though on a boxer lump.

As others have said the engine isn't powerful enough to detune for safety, besides that's what TCS is there for. I'd be surprised that they'd even leave that dip there if it was easily cured as its the only thing that ruins a perfectly good torque delivery.

It has been shown time and again that the dip is NOT just tuning related. Yes, it can be reduced in depth and duration by a small margin with tuning alone. However, what has show the complete ability to remove the dip and in some cases create a mound of power where the dip used to be is long tube headers.

Simply put the "dip" is a culmination of compromises that can be removed with BOTH hardware and software.

It's the cams

I doubt that TBH as it would make little sense to having a "hole" in the power band. Cams would generally see either a defficiency in top end or low end power depending on the profile.

It could be a combination of the intake manifold and cams, but I'd be suprised if it wasn't the IM that was the main culprit.

It's pipe acoustics, intake and exhaust.

TMC/FHI used acoustic tuning to create massive low end torque (for a 2.0L NA motor) which creates the 'dip' out of the super low-end and normal mid range.

These 'dips' have existed in bikes as 'flat spots' for ages. They are pipe related there, pipe related here. Evidence comes from the only exhaust company doing real header R&D, Nameless. Major changes in pipe design led to major changes in the power curve.

This has been discussed a lot, for a long time, but people refuse to make any attempt to understand the 'why' part because the science is hard.

The first torque hump is because of DI...It makes for some "meaty" torque right around 2500 since it atomizes the fuel pretty well despite low RPM.

I will look for the source.

This may be true, but you didn't need to add the last part about people refusing to understand the why part, when I clearly made an attempt. Also, judging from your condenscending tone you must be the expert and not the F1 engineers that wrote the article. Hmmm.... But thanks for your added info. I agree what hou said but to add another piece, the intake has clearly been designed with the utmost attention to hp, as those power figures that nameless is getting with only a header and 3" exhaust, wouldn't be possible if it wasn't. So I go back to ignition timing as being a main culprit to the torque dip. This is also supported by the dyno graph of nameless showing that it simply only shifted the torque dip to earlier in the Rpms and also a shorter duration.
Cheers.

This^. I wonder if acoustics could also explain the somewhat sinusoidal nature of the dip.

Although they are not strictly an exhaust company, and are nowhere near the size of Nameless, you're forgetting P&L. They had a header out just prior to them, and included the vband cat/turbo swap just prior to the overpipe that Nameless is now adding on.

I should have mine back on soon, this time sporting an intake.