Torque dip reasoning solved?

[Hawaiian]

Originally Posted by WingsofWar

Discussed, and acoustics have been noted to be the greatest effect of this phenomenon.

Also please shift your paradigm, as its not a dip but more of a switch, its the end of extreme scavenging during low RPM.

So true, This thread was solved after only 2 pages!

[WingsofWar]

Originally Posted by Gords_zenith

Well if that is true, than my apologies. I was only trying to show that maybe timing is the key culprit, but like everyone has pointed out, it's clearly the intake runner length combined with avcs that plays a bigger role.

no need to apologize dude, if you felt you needed to share something that was different to bring more information to the table theres no reason to be sorry for those actions. We ask, we research, we learn, then we ask some more. Wrong or right, that's of no consequence to the quest for knowledge.

[mad_sb]

Originally Posted by WingsofWar

no need to apologize dude, if you felt you needed to share something that was different to bring more information to the table theres no reason to be sorry for those actions. We ask, we research, we learn, then we ask some more. Wrong or right, that's of no consequence to the quest for knowledge.

Yup, hence why i like to post proof when i can. Before I started tuning my FR-S I was sure it was all tuning too. After a couple trips to the dyno and plenty of log data latter i changed my mind.... especially after seeing Nameless and P&L's results from equal length long tube headers...

There are still more NA gains to be had without cracking the seals on the motor with the intake manifold, though how much remains to be seen... At least for now we have lots of options for headers, both long and short tube, tuned and un tuned

[itwillboost]

Originally Posted by Dimman

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.

Bam, that's well put and it's rare to hear some one talk about the acoustics. I remember when I was learning about tuning n/a cars and people started talking about this how confused I was. For people who don't understand it's all about getting the intake and exhaust gases in and out at the right time for optimal intake and combustion.

I don't get why people are complaining so much though most older cars 200hp was plenty to have fun in.

[Rayme]

Originally Posted by itwillboost

Bam, that's well put and it's rare to hear some one talk about the acoustics. I remember when I was learning about tuning n/a cars and people started talking about this how confused I was. For people who don't understand it's all about getting the intake and exhaust gases in and out at the right time for optimal intake and combustion.

I don't get why people are complaining so much though most older cars 200hp was plenty to have fun in.

So acoustics, it's kinda like a 2 stroke tuned pipe but reversed pretty much eh?

I love 200 HP, not too slow and you can let the engine sing for a longer time before hitting overly stupid speed...kinda like a Ninja 250R

[Dimman]

Originally Posted by ottopilot

So acoustics, it's kinda like a 2 stroke tuned pipe but reversed pretty much eh?

I love 200 HP, not too slow and you can let the engine sing for a longer time before hitting overly stupid speed...kinda like a Ninja 250R

Same principal of sound energy used for scavenging from the exhaust stroke. There is also wave transfer from exhaust to intake during overlap, plus the intake can generate an independent wave when the intake valve shuts on high velocity air flow.