The FRS torque curve

[DeeezNuuuts83]

Originally Posted by carbonBLUE

im pretty sure toyota knew there would be a dip right there from the get go, im pretty sure it was also considered when looking at DD gas mileage.

http://www.ft86club.com/forums/showt...200#post204200

this is the first 86 owner in the US and hes getting 27~30 mpgs with spirited driving and fast highway cruising speeds

from reading a lot of different threads I imagine the dip comes form a collection of these things:
1: header design due to boxer shape
2: harmonics
3: cam phasing
4: gas mileage(pretty sure the dip wouldnt look as bad if they didnt tune gas mileage into the equation)

some people say its the direct injection, but i disagree, when the car has the pedal to the ground, Direct Injection is always on
when we can get this car on a dyno and study timing, a/f ratios, duty cycles for port and direct injection, bench flow the heads, ect ect

we wont know for sure what this engine is capable of... but im excited for the first 10 years this car is out.... lots of dif mods, ill probably have 2-3 engines in my garage in 5 years just for tinkering :P

Thanks for the reply and also for the info. But on the topic of the dyno plot numbers possibly being due to intentions of better gas mileage, with a six-speed and its ratios, does anyone know at what rpms the car would be in when cruising at normal highway speeds (say, 60-80 mph)? And have any automatic FR-Ss been dyno'd yet? I'd assume that given that dip from ~3300 to ~4600 rpm, cruising speeds would put it at a bit below that unless you're going 80+ mph.

[DarkSunrise]

It will depend on what your expectations are.

For instance, even at the dip, the BRZ is putting down more torque than an RSX-S. I posted this graph on a different thread, but I think it helps put the dip into perspective:



The BRZ makes more torque across the board, including at the dip, until 7000+ rpm. So if you think the RSX-S has adequate midrange torque for daily driving, then you'll think the BRZ is fine or even better (they're comparably geared).

If you haven't driven an RSX-S, you can substitute a comparable weight/torque car, like the 8th gen Civic Si, or NC Miata.

I'll also add, I drove an FR-S automatic during a 1st drive event. The dip in the torque curve was not really an issue, at least from what I could tell wringing out the car on a course in mainly 1st and 2nd gears.

[smbrm]

Originally Posted by DeeezNuuuts83

Thanks for the reply and also for the info. But on the topic of the dyno plot numbers possibly being due to intentions of better gas mileage, with a six-speed and its ratios, does anyone know at what rpms the car would be in when cruising at normal highway speeds (say, 60-80 mph)? And have any automatic FR-Ss been dyno'd yet? I'd assume that given that dip from ~3300 to ~4600 rpm, cruising speeds would put it at a bit below that unless you're going 80+ mph.

It would be interesting to see the injection map to see when Direct & port are used?

[carbonBLUE]

Originally Posted by DeeezNuuuts83

Thanks for the reply and also for the info. But on the topic of the dyno plot numbers possibly being due to intentions of better gas mileage, with a six-speed and its ratios, does anyone know at what rpms the car would be in when cruising at normal highway speeds (say, 60-80 mph)? And have any automatic FR-Ss been dyno'd yet? I'd assume that given that dip from ~3300 to ~4600 rpm, cruising speeds would put it at a bit below that unless you're going 80+ mph.

i would say its tuned for better gas mileage when driving spiritedly, shifting at 4-5k on public roads, the first frs owner drove spiritedly up to 4k and got 29 mpgs
my current car is like that as well, during the 3-5k rpm range fuel duty cycles are lower than at 2.5k rpms(less fuel is going into the chamber at 4k rpms per revolution vs at 2k) this also has to do with resonance frequency of the metal, in my engine the metals vibrate the least from 3-5k rpms allowing just a bit less friction thus less fuel needed per cycle, there was a big write up about it back in 2007 when someone was doing research and trying to figure out how toyota was able to achieve that, its lost in the newcelica.org threads , i cant find it anymore...

[coyote]

Originally Posted by DarkSunrise

It will depend on what your expectations are.

For instance, even at the dip, the BRZ is putting down more torque than an RSX-S. I posted this graph on a different thread, but I think it helps put the dip into perspective:

I think overlaying this plot would better put things into perspective.



That's the engine I want in my BRZ.

[smbrm]

More insight here:

http://www.ft86club.com/forums/showthread.php?t=3583

[coyote]

Self explanatory, really.

[SUB-FT86]

Originally Posted by carbonBLUE

ohh yeah and the tc has a horrible tq drop off...

173 whp = 200 bhp = 14.5% loss

143 wtq = 165.32 tq

200 hp and 165tq vs 2ar-fe 180hp and 173 tq

2700 lbs car vs 3100 lbs car

tc
First Gear Ratio (:1): 3.54
Second Gear Ratio (:1): 2.05
Third Gear Ratio (:1): 1.38
Fourth Gear Ratio (:1): 1.03
Fifth Gear Ratio (:1): 0.88
Sixth Gear Ratio (:1): 0.73
Reverse Ratio (:1): 3.56
Clutch Size: N/A
Final Drive Axle Ratio (:1): 4.06

frs


4.1 final drive

the frs will def be faster

in first gear the frs puts down around 2458 lbft of tq
in first gear the TC puts down around 2486 lbft of tq

frs weighs 400lbs less, puts down 28lbft/tq less to the ground and get better real world gas mileage, plus its rwd


sorry i got bored and wanted to research and do maths...

You know you can't really calculate torque from two different dyno's right? IL dyno is notorious for reading high torque output. I would rather multiply first gear x final drive x 151 lb ft instead. I don't think the 2.5L TC-2 engine only makes 8 more lb ft with .5 more liters of engine. Maybe if it was 2.2 liters.

[carbonBLUE]

Originally Posted by SUB-FT86

You know you can't really calculate torque from two different dyno's right? IL dyno is notorious for reading high torque output. I would rather multiply first gear x final drive x 151 lb ft instead. I don't think the 2.5L TC-2 engine only makes 8 more lb ft with .5 more liters of engine. Maybe if it was 2.2 liters.

so you're THAT guy... if we all are getting those tq figures when we dyno, then the engine really is underrated we really do make 160 something tq at the crank

[Rayme]

You only feel the dip when you are at WOT. Just driving around it's really like there isn't a dip there at all. That being said, if you want to accelerate fast downshift so you're over 4K and get over with the dip. There is more than sufficient torque at low rpm for quick city driving, and it's quite smooth power delivery too.

If it wasn't for DI, the dip would creep further down the RPM, it would be worst.

[MyNave]

this video shows the torque dip and kinda shows how to get rid of it
[ame="https://www.youtube.com/watch?v=iM_QmVF2-fQ&index=1&list=PLHxU7q4gi5_sFJCSzL7x5zPsz4WxzuKgd "]Searching for Torque - Header & Exhaust - FR-S Long Term #4 - Everyday Driver - YouTube[/ame]

[kch]

Originally Posted by MyNave

this video shows the torque dip and kinda shows how to get rid of it

this thread is almost 4 years old, man

[Tcoat]

Originally Posted by kch

this thread is almost 4 years old, man

Although surprisingly most of the people posting to it are still active. I bet they know the way to fix it by now though.
Much funnier when somebody replies to a 4 year old post where none of the people have been active for 3 1/2 years.

[finch1750]

We need a mod to move this post. It belongs in the engine and/or tuning forum