This is reminiscent of the LS1 days where 305HP rated F-Bodies routinely pulled 300HP / 300 pound feet on dynos.

Using a 15% standard drivetrain loss ratio, this 275 at the wheels is roughly 325 HP at the crank. I am unsure if this is a happy dyno, but under-rating a 4 pot by 50HP seems to be a bit much. I haven't spent much time at dynos since I gave up the SLP Firehawk, so maybe things are different. In this ancient time, I felt that a dyno session was as hard on a car as a day at the track. Just my 2 cents, only worth a single penny in today's economy.

 

Impressive numbers. As mentioned, dyno's vary. But hey ...I don't mind quoting you on those numbers.

 

The main reason why I got the dyno is to see if the Apexi N1 single exhaust adds any more HPs to the car. I’ll be installing today and taking back to get dynoed in a week or two. I’ll be sure to share the results!

 

Very fascinating. Thanks for sharing!

 

Went back to get the WRX dynoed with the Apexi N1 installed - added 10hp and 3tq for a final reading of 285.4hp and 275.3tq!

This is just stock + Catback, but I’m sure the larger hood scoop and Rays CN28 wheels are contributing to the power increase…

 

Spoiler

 

What did you do with the big blank spot on the other side? Why a single exhaust? With my OCD it’d drive me nuts seeing that big hole on the other side. 😂

 

 

I was actually looking forward to someone finally doing this the correct way. However, with the changing of the wheels on the second run. The results are now corrupted.

 

The wheels from the 1st and 2nd dyno runs are the same - both CN28- I was comparing it to Subaru’s claim of 271hp and that’s NOT to the wheels! Could it be that Subaru is under reporting their hp/tq figures?

 

There are no AWD dynos in my area...that I can find. But I can tell you, that even stock, the engine feels more powerful than Subaru lists. I've driven cars that didn't feel as fast that had more than 300hp. The key word there is "feel". I've never measured the performance of my car. Just can't bring myself to abuse it with a hard launch.

 

Sorry BlackDemonVB. My mistake. You did do it right. I thought you changed wheels between dyno runs. Thanks for the update! Although having the lighter wheels on may have given you the 4hp difference over Subaru's claim?

 

I brought my stock VB to get dynoed today to get a baseline reading before I install an Apexi single exit exhaust. This shop works mainly on Subarus and they were surprised at how much this stock VB made! I too was pleasantly surprised. I hope the exhaust increases my hp. View attachment 336663 View attachment 336664

Looks good. I’m still debating on waiting for warranty to expire or start doing stuff to mine

 

I mean that is around the advertised hp

 

Car manufacturers advertise engine HP and TQ because it’s a larger # and more impressive. . If you factor in a 15% loss from the engine to the wheels, then the engine HP would be 323.5HP if my car is putting out 275HP to the wheels.

 

Good example, the camaro zl1 is advertised as 650 hp, but they dyno around 530 ish hp. Manufactures usually advertise the hp at the crank, and not the wheels. Sometimes Manufactures will under rate their advertised hp, BMW does it, along with some others, and this wrx feels the same. It dynos higher than it should, almost to the factory crank numbers but to the wheels instead.

 

Nice to see but that could also be a happy dyno as that seems higher then what I’ve seen from everywhere else.

 

I was watching Boost Controlled Performance on YouTube and they have seen stock 22 WRXs HPs as low as 240s and even as high as 280s stock! I also thought that maybe that the dyno I took it to may be happy, but glad to see that other dynos have seen similar HP readings.

 

Most dynamometers are not properly calibrated to provide an accurate SAE output.

Internal combustion engines have varying output depending on environmental conditions - ambient temperature, pressure, and humidity play a major role. To compare results between runs, dyno software allows the operator to apply a correction factor to correct the reading to 1 ATM and 22degC ambient conditions.

Since most enthusiasts don't understand how dynos work, correction factors and calibration aren't considerations, and many tuners will manipulate the output to make the number look larger in order to please the customer.

The important metric is a comparison of measurements before and after modifications, not an absolute number. This dyno run only has a 1% correction factor which amounts to a few horsepower, but we also don't know the last time the dyno was calibrated against an SAE standard (if ever).

The best way to compare "real world" performance is to look at the quarter mile performance, which is generally done on the same track in each publication. A cautionary point: the environmental factors will play just as large a role here as with the dyno. The 2022 WRX ran ~ 14 sec @ 100mph quarter mile stock in journalistic testing. This is very similar to the outgoing VA WRX, if perhaps a tad bit slower. The VB is about 100 lbs heavier than the VA and so a 3hp increase is indeed conceivable. I don't believe the car is severely underrated in horsepower from the factory.

 

The single exhaust is awesome, can't stand dual exhausts on a 4 cylinder.

 

What does the number of cylinders have to do with anything?