I see what you mean. I thought you were referring to tuning Toyota variable intakes in general. I think it would be near impossible to use a three stage intake without spending huge amounts of money and making one off parts to adapt the system.

Here is some graph of the intake I think. Don't know what is it about but maybe there could be some relation between both this graph and the dip in torque.

Nah that's the intake noise piping thing. Supposed to give the engine more audible growl as the rpms pick up. I think I'm going to remove that crap.

Yes me too I'd remove it. It just thought it could be restrictive what would explain the drop in power and torque.

It's possible that it affects tuning but it looks like a pretty small tube so I don't think it'll have much of an effect. But IMO the idea of piping engine noise into the cabin is pretty stupid.

beats this,

[u2b]vLs8YcWMIx4[/u2b]

Lol

My theory on the dip is acoustics. We haven't heard of any variable intake configuration so I think this is a pipe (exhaust and/or intake length) induced 'flat-spot' like on bikes.

Reason being is for the sizing to flatten out the curve as much as it does on either side of a more natural inertial torque peak of ~4800 rpm, there will be neg(intake) or positive (exhaust) waves that had to be accepted as a compromise.

A header and AVCS tuning can probably 'fix' this, likely by moving the torque/power curve up the rev range, but naturally sacrificing the low.

The curve is actually very good. 90% torque from about 2,500 to 7,450 RPM. That's great. The little dip in the midrange will likely barely be felt. Dimman might be right on the acoustics; but we'll have to wait and see for sure as we start fiddling with both hard parts and ECU tuning.

I have a hunch there's torque left on the table at 3K and 5-7K RPM, where the torque mysteriously shelves perfectly flat. Porsche's n/a curves are curiously similar.

Is this my 4th or 5th 'final answer' on torque? Heh...

I'm liking this graph, the flat torque curve above 4k is pretty exciting. *Sits down and waits for US pricing*

http://i43.tinypic.com/63u8uf.jpg
And with about 15% losses
http://i39.tinypic.com/2rh8e9s.jpg

edit:

my mistake, you convereted the numbers correctly.

the reverse power/torque graph threw me off.

Second one in the post just above looks converted to match the 170whp from the vid.

I hate looking at the numbers of this car on paper...:help:

Comparison 1:
Honda S2000 (F20C engine) vs Toyota FT86:



http://s14.postimage.org/8lghaaue7/torque.gif




http://s15.postimage.org/v6t9mapgp/image.gif

Curves look very similar. Those who have driven an S2000 will know how the BRZ feels, minus 2000rpm. Makes me wonder if Ti retainers and valve springs will let this engine spin to 9000rpm and continue making power.

Comparison 2:
Honda Civic SI (K20 engine) vs Toyota FT86


http://s13.postimage.org/dhgfr0311/Civic.jpg

from another forum

http://www.rs25.com/forums/f5/2146164-post4.html

essentially, it's an oil problem

whether this new engine will be able to spin to 9-10K will be found out soon enough.

Yeah, looks about right when scaled on same units with estimated whp values. Nicely done :thumbsup:

Here's another one converted to English units

Except for being mathematically impossible, sure. :D

Wow nice and flat :)

This is an interesting idea. However, I just don't think its possible to get such good torque across the range on an NA motor with a fixed intake size/length, there must be some sort of valve altering intake properties. Either way I agree that if you were willing to sacrafice low end power you probably could get rid of the dip

eh, oil isn't really the problem ;)

http://www.youtube.com/watch?v=_F30Vzb0qHg

This was Dom's budget destroker with stock oiling system. Lived happily until it's guinea pig phase was over and it was torn down and inspected.

lol, I wonder how many people actually noticed :P

Yeah I thought your long-rod motors spun to 9K without problems. How's the thread on NASIOC where EQ's trying to trash the motor?

a bigger free flowing exhauast and bigger intake system just might fix that dip in the torque curve

Doubtful. Larger exhaust diameter combined with most "cold air" intakes negatively affect low-end torque, so if anything, it'll smooth out the bump between 2500-3500 rpm.

Ah thanks for the reply, I understand a little more now!

I see what you did there. :laughabove:

THe torque curve looks quite good considering that it is an NA engine. with most of the torque available from 2500 - 7000RPM.

There could be a number of reasons behind the dip ranging from switching of valve timing, axillary components, intake and exhaust resonance, etcs.

For me, this slightly bumpy torque curve will give the engine a unique character. It probably won't win races but it will be more exciting to drive as the driver anticipate the torque build-up then followed by a rush from 4k to 7k (3000RPM).

Can't wait to test one on our MAHA dyno...

Do you really feel torque? I thought it was Hp that actually moved the car, if anything you might feel the slight dip in Hp. Am I wrong?

Yes, you are :D

You feel torque. Horsepower is just a function of torque/rpm.

No, it's torque that moves the car, and that is what you feel. Horsepower is just some complex number: (torque X 5252)/rpm. It is important, but torque is what puts you back in the seat.

Yup! Dynos don't measure HP, they calculate it from the torque measurements.

eh, he found he had no ground to stand on. It is however an engine that isn't for everyone.

Still trying to get reliability over 10k...need better valve springs.