Dyno charts for my 2

[Gravity]

Here's the dyno results today. All 3 pulls were identical.

I'm a little confused though.... I removed the second cat today and went to a smaller resonator, and i almost feel (butt dyno) like I lost a bit of power... but I've got far more torque than I thought I'd have... I'm actually impressed with the BHP numbers, but sort of disspointed with the drivetrain losses. And I'm dynoing wheel HP lower than stock (according to CorkSport's SRI dynos) I'm almost wondering if I should put the second Cat back in... Could removing that second cat have actually lowered by HP?

At any rate... here are the charts!

 

[BRIAN_MP5T]

Wow, That is the flattest power curve I have ever seen.

Its as if the engine simply makes the same HP all the way.

 

[Gravity]

I was pretty amazed by how flat the torque curve was. The HP curve only looks like that because the scale is so low... Silly 100hp engine...

 

[Mazdamatic]

seems about right. need a box on that filter for the best intake setup. with my exhaust now i expect 100hp and 10lb ft LOL.

i think you should also ship me a yozora wing lol i like them.

 

[Gravity]

A couple of things still bother me though:

1) my modified max HP is LOWER than Corksport's stock max HP. In theory we should be running the same car. Both NA, both same model year, and both acquired within a couple of months of each other (give or take).

2) After removing the second Cat from my exhaust set-up, the car feels subjectively slower. Less subjectively, when my new clutch went in a couple weeks ago I could hard shift to second from redline hard enough to get some pretty significant driveline shock (this, of course, was after i had properly bedded in the clutch.. don't worry!) Now under the same conditions I can barely get a chirp. Is it possible that removing that second cat has somehow compromised flow velocity or some such enough to see a drop in HP?

3) I'm looking at losing 14hp and 10ft/lb or so to the drivetrain... Are those fairly high losses at these output numbers?

I'm now wishing we'd done one dyno pull before and after the cat had been removed!

 

[Racebrewer]

Hi Grav,

All dyno's read different from each other. It depends upon type, construction, operator technique, correction factors for weather, etc, etc. It makes it diffiult to compare at different locations.

Also, what were you running for gas and did you drive it much after the exhaust changes?

John

 

[Gravity]

I sort of figured about the dyno differences.. that makes sense. We sit around 300m (1000') elevation. Temp was around 20C yesterday.

I'm running 89 in the tank right now. I only drove it for a little while, maybe 50 or 60kms after the changes yesterday. I got home and cleaned my SRI filter (it needed it) and reset my ECU to see if a new learning cycle would help. About to go driving now, but I'll have a passenger for the first while so it won't be a great comparison.

 

[magnumP5]

I'm going to play devil's advocate a little bit...

A couple of things still bother me though:

1) my modified max HP is LOWER than Corksport's stock max HP. In theory we should be running the same car. Both NA, both same model year, and both acquired within a couple of months of each other (give or take).
As racebrewer said, all dyno's, even ones of the same manufacture, read differently so comparing your results to Corksport's isn't valid. Also, there is car-to-car variation so even comparing you car to Corksport's isn't valid.

2) After removing the second Cat from my exhaust set-up, the car feels subjectively slower. Less subjectively, when my new clutch went in a couple weeks ago I could hard shift to second from redline hard enough to get some pretty significant driveline shock (this, of course, was after i had properly bedded in the clutch.. don't worry!) Now under the same conditions I can barely get a chirp. Is it possible that removing that second cat has somehow compromised flow velocity or some such enough to see a drop in HP?
It's very possible the car is setup to make the most power from the factory. Bear in mind the 2 is supposed to make 100 bhp out of a 1.5L engine. How much power were 1.5L engines putting out 20 years ago? To use the RX-8 as an example, the factory intake and exhaust are designed to optimize power. Just about every intake/exhaust modification will result in a negative or zero power gain. Remember, a team of experienced engineers designed this car to be a balance of economy, reliability, power, and emissions. Anything you do will change this for better or worse.

3) I'm looking at losing 14hp and 10ft/lb or so to the drivetrain... Are those fairly high losses at these output numbers?
Okay, I'm lost here. How are you figuring this? Unless you dyno'd a stock car I don't see how you can estimate drivetrain losses. Remember, you can't use Corksports reported numbers for your car.

I'm now wishing we'd done one dyno pull before and after the cat had been removed!

I sort of figured about the dyno differences.. that makes sense. We sit around 300m (1000') elevation. Temp was around 20C yesterday.

I'm running 89 in the tank right now. I only drove it for a little while, maybe 50 or 60kms after the changes yesterday. I got home and cleaned my SRI filter (it needed it) and reset my ECU to see if a new learning cycle would help. About to go driving now, but I'll have a passenger for the first while so it won't be a great comparison.

Unless this is the lowest grade of fuel you can get in your area you're wasting money. The 2 is designed to run on 87 octane in the US and you'll see no benefit from running anything higher unless you've made modifications (turbocharging, advancing timing, etc.) necessitating it. Octane is a measurement of knock resistance!

 

[Gravity]

This all makes sense to me. Though I would push back a bit on design from the factory. It's pretty common practice for manufacturers to strike a balance between comfort, performance, economy etc... And often times I think most mainstream manufacturers tend to err towards comfort and economy and more away from performance. Were this not the case forums like this would probably not exist, and we'd likely not be having this conversation ;-)

My approach to upgrades has always been to only spend money where I expect I can get measurable gains... I'm probably not always right, but I like to do my research! So all these opinions are very useful. esp with this exhaust part, since I've read about 50 different exhaust articles and with a few main points, people seem to have vastly differing opinions, generally not backed up with any real science!


As far as the drivetrain losses go, I'm basing my numbers on the dyno results. They supply engine HP and TQ and wheel HP and TQ. So I'm making my assumptions based on those numbers. However I don't fully understand the mechanics of how they arrive at the engine power number from the dyno runs, so I'm more than willing to be wrong on that.

And yes, i usually put in the lowest grade I can get.... With gas sitting at around $1.30/L (~$5/gal) I have no desire to spend more than I need ;-)

I'm going to play devil's advocate a little bit...




Unless this is the lowest grade of fuel you can get in your area you're wasting money. The 2 is designed to run on 87 octane in the US and you'll see no benefit from running anything higher unless you've made modifications (turbocharging, advancing timing, etc.) necessitating it. Octane is a measurement of knock resistance!

 

[Phone]

Octane is a measurement of knock resistance!

Wrong.

 

[Racebrewer]

Don't forget, there is the octane when the gas is refined and then there is the octane when the gas finally gets into your car. It may be two different things.

If the octane has deteriorated due to the good stuff evaporating out, any transient knocking will cause the ECU to retard the ignition timing. Then you lose power and mileage.

John

 

[BRIAN_MP5T]

Wrong.

You are wrong... Actually...

He is correct (although it is a very simple broad stroke definition of something that is a bit more complicated than that..)

 

[Gravity]

Yea. I figure I'll give it a few hundred km. Driving around today felt a little more normal. This could easily all be in my head too. Without having a before and after dyno, it could very easily be all psychosomatic!

Don't forget, there is the octane when the gas is refined and then there is the octane when the gas finally gets into your car. It may be two different things.

If the octane has deteriorated due to the good stuff evaporating out, any transient knocking will cause the ECU to retard the ignition timing. Then you lose power and mileage.

John

 

[Phone]

You are wrong... Actually...

He is correct (although it is a very simple broad stroke definition of something that is a bit more complicated than that..)

Octane isn't a measurement of knock resistance; I literally have no idea how he got Octane = Knock Resistance! Yes, there is cause and effect where if you run too low of an octane, you wind up with detonation; however, the octane rating refers to how resistant to self-detonation under compress the gasoline is. Octane isn't a measurement of knock resistance, it's a molecular compound.

 

[BRIAN_MP5T]

Thanks Nerd, We all know the Textbook definition... However, the overall result of all of that crap that we don't care about is....


Drumroll....


87 will detonate sooner than 89
89 will detonate sooner than 91

He is correct and you are a fool for simply saying "Wrong!" without telling him why "You Think You Are Correct"

 

[Mazdamatic]

>2012
>still using fossil fuels

i fill my car with moonshine and civic blood

 

[magnumP5]

Wrong.

Octane isn't a measurement of knock resistance; I literally have no idea how he got Octane = Knock Resistance! Yes, there is cause and effect where if you run too low of an octane, you wind up with detonation; however, the octane rating refers to how resistant to self-detonation under compress the gasoline is. Octane isn't a measurement of knock resistance, it's a molecular compound.

http://en.wikipedia.org/wiki/Octane_rating - "The higher the octane number, the more compression the fuel can withstand before detonating ..."

In other words, knock resistance...

Stop being a dick. I've seen nothing but condenscending posts from you on these forums. You know damn well I was referring to the rating and not the compound.

Gravity, sorry for cluttering your thread but I'm glad to see a civil response to some criticism I will agree most manufacturers err toward economy and comfort, especially with cars in this segment. Even though I don't have any intention of doing power modifications to my 2 (it's my DD) I do like to check out these threads to see what kind of stock power and gains people are seeing.

 

[Gravity]

I'm all about civil responses! Well, at least when people aren't a complete waste of time... Like you (and most others it would seem), I've seen little to nothing out of our friend here that hasn't been arrogant, condescending, douchey, and more often than not, wrong or at least excessively pedantic. A waste of time and a waste of skin, and completely destructive to the purpose of these forums in the first place. It's too bad you can't get banned for being a useless troll.

At any rate, back to the productive discussion! I'm pretty much squared away on all the dyno info... The only thing I'm still trying to work out is if I could actually be seeing a loss in power from removing that second cat. My butt certainly feels it, but without a before and after I've got no objective way to be sure!

Gravity, sorry for cluttering your thread but I'm glad to see a civil response to some criticism I will agree most manufacturers err toward economy and comfort, especially with cars in this segment. Even though I don't have any intention of doing power modifications to my 2 (it's my DD) I do like to check out these threads to see what kind of stock power and gains people are seeing.

 

[magnumP5]

At any rate, back to the productive discussion! I'm pretty much squared away on all the dyno info... The only thing I'm still trying to work out is if I could actually be seeing a loss in power from removing that second cat. My butt certainly feels it, but without a before and after I've got no objective way to be sure!

It's possible you've shifted the power band some. Perhaps losing some power down low to gain it at higher engine speeds? You're right though, without any dyno numbers it'll be hard to say for sure. Is it possible to put the cat back on? You could always do some "street legal" speed tests to see if you're 30-60 mi/hr (sorry, U.S.) acceleration times are any different in any single gear.

 

[njaremka]

here's my take on it... (and, i'm probably reiterating some thoughts already expressed...)

your car is showing wheel power of 92hp and 103ft-lbs, and that's only with an intake and exhaust? that is some serious gain, especially on a 1.5l engine. stock ratings are 100hp and 98ft-lbs at the engine. figure 15% loss for FWD drive train, and you'd be seeing 85hp and 84ft-lbs. so, for just an intake and exhaust, you're looking at +7-8hp and +18-20ft-lbs!! holy crap! throw some light wheels and a light flywheel on that car, and you'll have a nice little screemer on your hands.