Cobb Tuning dyno pull

[serialk11r]

Load bearing dynos are theoretically better since you can adjust the load to imitate the car's mass or hold the power constant to find how much energy the transmission is sapping...greater load would give you a higher number since you're reducing the rate that the rotational mass is accelerating.

[zAnSh1n]

yea, i didn't believe him...

[Jordo!]

Originally Posted by serialk11r

Load bearing dynos are theoretically better since you can adjust the load to imitate the car's mass or hold the power constant to find how much energy the transmission is sapping...greater load would give you a higher number since you're reducing the rate that the rotational mass is accelerating.

They're better for tuning (although nothing beats the road or track) but as far as measurement goes there is not great consistency from shop to shop with various load holding dynos.

A dynojet reading will vary insignificantly from shop to shop -- the speed the known weight of the drum rotates is the yardstick, and it is consistent.

Quick comment on Cobb -- they dropped the 370Z like a bad habit a little while ago. No further support. Hopefully if they do offer tuning software for the Toyobaru they will not abandon it before even the first refresh cycle.

[tranzformer]

Originally Posted by TheRipler

That looks like it says 190-some hp to me. Maybe it says 200. *shrug*

It looks like 149-150kw @ peak which is ~200hp.

[ashtray]

Why would Cobb put one on a dyno if they weren't considering tuning it or developing performance parts for it?

I bought the Access Port when it first came out (early 2004 I believe?) for my WRX. It's been a great 8 years of extra power. The $500 amortized itself quite well.

If Cobb adds a little torque here and there - maybe doesn't increase peak hp, but gives more hp throughout the band, and adds some toys in the Access Port, I think there would definitely be a market for it - especially from the Suby guys who have used them in the past.

[Gardus@Supersprint]

Hi guys, great to finally have independent testing.
I did a few comparative charts of the most similarly engined car I can get, which is the Renaultsport Clio RS 200cv.
The weight is pretty much the same, 1210 kg, engine size is 2000 cc, power is 200 hp.

These are the charts from our in house MAHA dyno. It's a brake dyno and well know for its precision. In the full charts you have all the info:
Norm-Leistung is flywheel power corrected
Morotleistung is the flywheel power
Radleistung is WHP
Schleppeistung is power loss
Drehmoment is flywheel torque.

Stock clio:

Full exhaust clio:


I couldn't compare the torque so i just used the WHP, which is pretty much the same for the BRZ, 164 whp.

Stock BRZ vs Stock Clio


Stock BRZ vs Full exhaust Clio


This will also give you some idea of the tunability of a 2.0 l engine, but the 86 engine may be better as it's newer, it has direct injection and maybe they had kept it more restrained.

In the end this car as stock will go as a Clio RS midly tuned, it's no bad thing but it certainly slower than most fo the same price range car. A Golf GTI will leave it in the dust on the straights.

I drove the Clio quite a few times and I can tell you in the slow tracks power is enough, but try it in Monza or any fast track and you will miss the power, especially if you have turbo or bigger engine cars around.
The Clio also have a very esploitable chassis and Brembo brakes as stock, so you can make the difference in the corners and braking zones, especially if you fit some semislick, we still have to see how the BRZ/86 works with sticky tyres in this area.

[Deslock]

I took a screenshot yesterday (I see S2kphile has one also). I roll my eyes when places like this mislabel dyno torque as wtq, but whatever



Its shape is similar to the dyno from the .jp website months ago:



And here's a version of the .jp website dyno converted to lbf*ft and HP:



Cobb's dyno torque drops off at 6200 instead of 6900 RPM, which is what caused peak power to be low. The good news is that below 6200 RPM it's underrated and/or has little drivetrain loss (only 6% less output than what's officially rated at the engine). It'll be interesting to see if other dynos produce similar results.

[Gardus@Supersprint]

It has indeed low drivetrain loss for a RWD car.
I really want to test it on our dyno so we can get all the data and not just these at the wheels values.

Torque comparison:

BRZ vs Clio Stock


BRZ vs Clio Supersprint

[blu_]

Originally Posted by zAnSh1n

yea, i didn't believe him...

It very well could be that surgeline will do open source tunes, but cobb won't develop an AP for it.

Its possible Cobb higher ups got pissed and made them take the video down, not Subaru.

[Allch Chcar]

Originally Posted by serialk11r

Hmmm speaking of gas, seeing the very rich looking AFR, I wonder what E85 conversion can do...and what would happen with E85+supercharger :O

EDIT: actually I just looked back at the AFR, and I think it tells some of the story. AFR is going up in the torque dip range, which means it's a volumetric efficiency issue I think, so the intake tuning theory sounds plausible (Subaru boxer engines all have a manifold like that, makes sense that they'd all see the same drop like that). Below 3000rpm it runs quite rich, that looks like the extra fuel they're using to combat the internal EGR effect of advancing the intake cams. The high end being so rich is a mystery though...

Some higher octane might do the trick. It'll be awhile at least before people start doing crazy stuff with the stock engine though.

It actually looks a bit too lean between 3.5-4k RPM, especially if that's a danger zone.

Originally Posted by dsgerbc

Post #23

Thanks! I missed that the first time.

Originally Posted by Jordo!

They're better for tuning (although nothing beats the road or track) but as far as measurement goes there is not great consistency from shop to shop with various load holding dynos.

A dynojet reading will vary insignificantly from shop to shop -- the speed the known weight of the drum rotates is the yardstick, and it is consistent.

Quick comment on Cobb -- they dropped the 370Z like a bad habit a little while ago. No further support. Hopefully if they do offer tuning software for the Toyobaru they will not abandon it before even the first refresh cycle.

Cobb started work on the AP for the EJ25 N/A but they dropped that too!

[PERRIN_Jeff]

Originally Posted by serialk11r

Load bearing dynos are theoretically better since you can adjust the load to imitate the car's mass or hold the power constant to find how much energy the transmission is sapping...greater load would give you a higher number since you're reducing the rate that the rotational mass is accelerating.

I think what a lot of people don't understand is that most dynos read force using a Strain gauge. Very few use the rate of acceleration of the drum (with specific weight). So as long as the tires are not breaking free on the dyno, it will read just fine. The variables to actual HP (besides drivetrain friction) is the tires, and how hard they are strapped down, and the calibration of the dyno. The other factor for dynos with no load cell are how fast the car makes a pull. Meaning a 200WHP car would take 20 seconds to make a pull, versus a 400WHP car, takes 10. The longer pulls effect the heat the engine deals with and adds to the load, which can effect HP reading a bit. And like the above poster said, not good for tuning.

I actually like the way they did the run with all 4 wheels going. This provides a comparable difference to a WRX. Also it keeps the TCS/SMS, and other things all in check. Lance told me they do this on all the RWD cars for that reason alone.

The only way everyone is going to settle down on this subject is seeing 4-5 dyno pulls from different cars and dynos. Typically the Surgeline dyno reads about 10WHP less than our Dynapack. But other local Dynojets read about 10WHP higher.

[SkullWorks]

Cobb also started development on the Gen Coupe and abandoned that to a corner of the shop.

Delock, Horsepower measured at the WHEELS is WHP, you measure this on a chassis Dyno, you can also measure torque at the hub on a dyna pack (slightly higher due to no rolling resistance or wheel/tire weight) or you can measure BHP (BRAKE horse power on an engine Dyno or commonly an engine Brake dyno)
what would you prefer they call the horse power measured at the wheel?

[Deslock]

Originally Posted by SkullWorks

Delock, Horsepower measured at the WHEELS is WHP, you measure this on a chassis Dyno, you can also measure torque at the hub on a dyna pack (slightly higher due to no rolling resistance or wheel/tire weight) or you can measure BHP (BRAKE horse power on an engine Dyno or commonly an engine Brake dyno)
what would you prefer they call the horse power measured at the wheel?

Labeling dyno hp as whp is fine. Labeling dyno torque as wtq is a misnomer (assuming wtq means wheel torque).

If COBB's curve is accurate, the 6MT BRZ with a 4.1DR has peak wtq of ~2110 lbf*ft in 1st gear and ~440 lbf*ft in 6th gear. That's more than I was expecting.

[UAmach1]

I'm not familiar with Subaru motors but N/A Ford and Chevy motors love to be 12.5-.8 A/F. If this motor is similar in that regard then just getting that A/F up will help that top end a LOT not to mention and timing and variable cam tweaks that can be done just from the tune. I've seen on a Zetec when getting the AF up from 11.5-12.5 and adding 7* have added about 20whp on a dyne jet.

I'd love to have one of these cars if a good tune/pulley/intake/exhaust will net nearly 200whp. With the look of the stock tune I wouldn't be very surprised if those items did indeed put the car in the high 180 or low 190 range on a dynojet.I wouldn't be shocked to hear people hitting 180's with just the tune alone. It will just take time for people to learn all the small tweaks. Heck maybe I'll stop my home grown Zetec tuning if I get a BRZ and learn to tune it myself.

What I love most about my Mustang is that I can throw around the rear, and it will just GO when I plans my foot. What I love most about my ZX2 S/R is that it handles great and feels nimble, much better on fuel also. If I can get the joy from both of those in 1 car and a few bolt-ons then I'll be instantly trading them in on it.