markotark

I own a subaru Impreza 2.0R that originally had 160hp and 0-62mph(0-100km/h) time of 8.8 seconds. Nothing special, i know. But i have installed an official Subaru sport-backbox for the exhaust and started using the 99 octane Shell V-Power as my normal everyday fuel. So i thought that the performance might improve somewhat. But imagine my surprise when i filmed 2 accellarations that both had 0-62 time around 6.9 seconds. So how is it possible to have that kind of jump in performance with just one minor mod. I mean that the acccellaration has improved by 1.9 seconds!!! The engine also feels a lot smoother and more eager to rev...and the sounds not too bad! If you wish to confirm these figures or just look and listen to my car...just search YOUTUBE with my name MARKOTARK. Could somebody explain what sort of horsepower-figures we are talking about here and how these two small changes are responsible for it. PLEASE HELP!!!!

TonyBurns

iTrader: (3)

The backbox probably did virtually nothing, the change in fuel on the other hand probably increased your performance due to the higher octane (burns better which = more power) but it could also be down to the fact your car is fairly new? and will loosen up a fair bit (10k+ miles) over time

Tony

The Rig

iTrader: (13)

looking at the vid, i get 7-8 seconds,but im using my analogue watch and its hard to know exactly when u start

gazskooby2006

hello nice looking car i would expect maybe a slight increase in speed maybe 8 secs or just under which is what it does on your clip as you set off at 1 sec and get there at 9 sec i think you would have to spend some cash to get 6.9 as thats only half a second slower than a turbo'd Impreza

markotark

Okay you off little faith...I measured it with a stopwatch 4 times after reading the comments. I pretty much know when the car starts moving and my times were between 6.95 and 7.25. Maybe saying it does sub-7 times is a bit much but low-7 for sure. And it's still 1,5 seconds faster than the official figures. The car felt more powerful after installing the new exhaust even before i started using V-Power, so how much power and where does it come from?

jaytc2003

iTrader: (1)

sorry to blow on your trumpet, but using a stopwatch isnt really accurate. Yu will be tenths out each and every time. The fact that you had 4 different times on 4 attempts says a lot.

Backbox may release a few bhp nothing major unless the oe backbox is highly restrictive. fuel may add another few bhp but not 1.5 seconds worth. That would be a heck of a power increase

silent running

If you seriously want to measure your before and after performance, forget 0-60 times. It's pointless, so inaccurate. Instead, if you must time using a stopwatch, try 0-100...this highlights differences in performance much more clearly than 0-60 does. Get a friend to sit in the passenger seat and start and stop the clock, when he (or she) thinks is right, leaving you to focus on driving.

Much better to just go quarter miling.

Obviously, run the tank of V-Power until empty and try normal petrol, leave the backbox on, that won't make any difference hardly at all. Once you've done your testing like that, fill up with V-Power and see what happens.

Microstar

I don't think the new backbox would make much of a difference unless there was something seriously wrong with the original.

The new 160bhp EJ204 engine in the NA Impreza runs a high compression (11.1 : 1 according to the Subaru UK website specifications) so I think that running a high octane fuel, like 99RON, could make a fair difference. I think this same engine gives up to 190bhp in Japanese market Subarus.

Also, you do get a bit of a difference in performance between vehicles, due to production variations and to weather conditions (on a cool damp day when the air is denser you will get a little more power out of the engine).
You also don't know how Subaru got their 8.5s 0-60 time - it was probably on a pre-production car and they may have changed the engine mapping etc since then.
It would be good to test it using some professional timing kit. Don't forget your speedo could be 5-10% out so when you read '100kph' it could actually be travelling at 95kph or so. Best to calibrate your speedo from a GPS.

gazskooby2006

easiest way is to find a impreza turbo have a drag race and you will soon see if your car is only a second slower

Microstar

That would be too difficult to do accurately I think.

Mind you, looking at his YouTube video it does look pretty quick for a non-turbo. Definitely sub-8 second I reckon, which is not bad at all.

silent running

Yes I agree it's probably 7 point something, but to then start getting into 2 decimal places when timing off video footage of a dashboard with a stopwatch...

jasonius

iTrader: (1)

Does look quite quick for a sport, but that could be the fact that it's in kph.

BTW it's much better to do in gear times, such as 30-70 and 60-100 through gears..

As a comparison..:

YouTube - WRX 30-70ish
YouTube - ktj 60-100 oct06

jaytc2003

iTrader: (1)

looking at youtube it does look to be just under 8 seconds taking a look at the seconds counter on the video when the speedo starts and when it hits 100kph

jasonius

iTrader: (1)

Try a 30-70 through the gears and let us know..