I wouldn't try the 3" exhaust yet, since you already have the 2.5". I took my exhaust off Sunday because I think the stock muffler may be restrictive. With the exhaust off, with boost the same, the difference between my best runs were .18 seconds ET and about 2.4mph. Yes, open exhaust was definitely faster, BUT, also consider that it's less weight (I don't know, maybe 40 or so lbs), and it's STOCK (probably restrictive). If I can run open exhaust, I'd do it all day long. I think 2.5" exhaust might be fine up to the mid to high 300hp range. I ordered the 3" one because who knows what will happen with my car.

People were suprised at the track when I listed my mods. Maybe my car was built on pay day or something.

 

The car was picking up to 17 HP without the exhuast - particularly from 6000 - 7000 there was a huge gain in that zone - SO - I have GOT to try the 3" and see what difference if any there is to the system I am using now

I would expect not much of a gain - maybe 7 - 10 hp at the most - but I would like to get the most power I can

Still the test pipe and 2.5" combination is a great value b/c you get 12 hp better than stock - for only $300.00 and it sounds great

If you are totally HP crazed like me and want every single HP you can get - you have to pay approx $850.00 for a full 3" turbo back system with test pipe to get like 20 hp or so more than stock

 

Are you running a stock downpipe, or 2.5" one? I am running a stock one, and when I dropped the exhaust at the track, I noticed that there's a lot of kinks and tight bends in it. Much ****tier than the rest of the exhaust. I think there might be power to be found there.

 

The stiock exhaust and downpipe are rediculously restricted. I installed a 3" turbo back a few weekends ago and man is the stock exhaust janky. Resonators everywhere and heat sheilds all over the downpipe. Not to mention bends for days. And heavy as hell ! ! Good lord that thing must weigh 70 freekin pounds.

 

One other point. As stated, the stock downpipe and exhaust are pretty restrictive and replacing it nets 10 to 30 peak horse power gains. However, the power and torque under the curve is substantially improved across the entire power range. Some owners who have replaced the stock exhaust report the car pulls much harder and longer thu the rpms. Peak HP is not the fun part... its the area under the torque curve.

Speedlimit......

 

I can nopt wait till they post up my 317 wheel hp dyno sheet - the trq curve to the left is GIANT ! Your right the exhuast removal yields mega trg - - suprizing - b/c that famous guy norris from the UK runs a 3" exhuaszt in his 711 wheel HP evo vii and says a small exhuast is necessary in the evo to make trq

Anyway - I am hoping they post up the dyno sheet soon

 

Here it is http://www.pruvenperformance.com/images/aldyno3.JPG
After living with a WRX for two years - its nice to have a turbo with some ***** down low !

 

somebody host his pictures

 

I am really hoping the 3" full exhaust is going to make some power for me. I wonder what the car will pull on the dyno with it.

Might go to the track again tomorrow night. I really shouldn't, because I haven't done any other mods yet. If I go tomorrow, I'm going to run open exhaust, and just leave it off till my 3" stuff comes in, hehe. The car isn't real loud, even at full throttle. I think in some of the video clips of Sunday's event has sounds of my runs.

 

impresive times. even tho i'm not into drag i wonder what my IMPREZA can do. how much power are you putting down? weight of the car? and does the EVO have LSD>..


thanks

 

I was putting down 286hp/274tq to the wheels at the AWD dyno at BM Tranny. That was with the stock exhaust on. I ran 12.7 at 106mph that way. With the exhaust off, I ran 12.5 at 109mph. I'm assuming the car makes a little more power with the exhaust off. Car weighed in at 3414lbs with exhaust on, 1/4 tank of gas, and somewhere in the high 3300lbs range (depending on how much gas I had at the time) with exhaust off.

From what I know, my Evo has open diff in the front, viscous coupling LSD in the transfer case, and a regular LSD (Is it Torsen?) in the rear.

 

From what I have seen this week on the dyno - the bigger FMIC picked up about 15 hp and takling the exhuast OFF the car also picks up about 15 HP

BUT you have a much bigger gain from 6,000 - 7,000 rpm with the exhaust off - thats where the stock one really falls off and running the exhuast system off really picks you up power - look at my dyno sheet posted above and you will see the power in the 6 - 7,000 range

 

OK, back from the track again.
It was hot as hell today, compared to all the other times.
Ground was hot.
Seems like nobody ran good times tonight, and lots of cars were breaking, probably due to extreme traction.

Made 4 runs tonight.
2.5" test pipe
Greddy BOV
SAFC2
Hallman boost controller @ 20psi (drops back to 19psi)
K&N filter
End of mods list. Stock exhaust intact.

1st run, 6200rpm launch. (only 18psi for some reason)
81 degrees.
Felt like clutch slip. Tires didn't spin. RPMs didn't move.
.678 reaction time (sucked. .500 is perfect)
1.863 60'
13.022 @ 105.41mph

2nd run
79 degrees. 5800rpm launch
Spun tires for a second then bogged hard.
.555 reaction time
1.986 60'
13.212 @ 106.03mph

3rd run
78 degrees. 6000rpm launch
Spun tires for a second again, then bogged hard.
.509 reaction time. WooHoo!!!
1.987 60'
13.312 @ 105.03mph

Was gonna go home after the 3rd run cuz I was pissed as hell, but couldn't leave without crackin a 12 second pass.

4th run
74 degrees. 6500rpm launch. Going for broke.
Blazed tires for a little bit, then slight bog.
.486 reaction time (redlight)
1.756 60' (when I saw this, I knew it was a good run)
12.731 @ 106.82mph

Then I went home.
Don't bother racing when it's hot, cuz it sucks.
If it's hot and humid out, stay home.
Have 1 or 2 video clips from tonight. I'll try to get someone to host them.

 

Your dyno numbers are really high for the mods you have. I'm pretty impressed. Are those numbers post-AFC tuning, and if so I'm curious what your numbers were pre-AFC.

Also, what did you put down stock.. I know you told me but I forget.

 

Nice runs bro - keep up the good work - seems like you are right in there with the times I was running on Sunday - with my exhaust

So it seems like the removal of your exhuast was good for like 4 mph in the 1/4 mile>?>>>???

The last run was great - nice launch !