Went to Topspeed to get retuned yesterday. Reason for the retune was a few weeks after the last tune by Doug my stock manifold took it's toll and started cracking around the EGT tap. Also the uppipe developed another leak. I can vouch 100% the car had no leaks when it was last tuned. Due to the insane cost of a stock manifold I started researching. Rich of MadDad Exhaust Systems just release the MadDad Equal Length Header (ELH) so I contacted him. We worked out a sweet deal and I agreed to critique and do a nice writeup for Rich. So there are NO changes to the last tune except for the headers and uppipe. At first I was disappointed. Made I think 2 more hp and a few tq more on the first pull and the headers simply fell on it's face up top and lost like 20 hp. Then Scott said Dude your car is FAT. It was running 10.2 AFR! No wonder I was throwing flames everywhere. All said and done I now have an insane 18g powered 2.0L. Went from 343 hp and 316 tq to 351 hp and 337 tq. Midrange has REDICOULOUS tq gains. There are gain EVERYWHERE. 14 more tq down low and all. Makes the same from 6K up like before now so I lost NOTHING. Scott took the time to smooth out the driveability and the car is simply like butter. I'm in love with the WRX all over again Scott also took the time to talk about his impressions with these headers. Doug still doesn't seem to like them and said this test was redundant because of the different days but I personally disagree. Either corrected or uncorrected the dyno says it make more power. Scott did something he 'never' does and went to talk in theory and I think he's right. He didn't have to change much. Most of the tuning was from 6K up where the EGT's dropped so much that you could get more aggressive. All said and done I think Scott told me that these were the only headers that he could recommend as a good mod if you wanted them.
My impression of the header are just that. I think it may "Work" ok on this car, but just like the perrin header once you start to make over 350whp it chokes the topend. Like I said when you were here, the only way to have proof is to tune the car without the header and then install it the same day and re dyno. Last pull from the previous tune to your first baseline pull with the header showed an increase in about 4hp and 15tq down low below 4.5k. But you lost 15hp @ 6k and about the same tq. So if you want to go off just a part standpoint then it makes little hp down low but lost a ton up top. The additional power gained was from now being able to run the tune a bit more aggressive because of the lower egts. Which if its the lower egts that are allowing you to make more power, then any header will show similar gains if not more. Take M2 header I run on the race car, its 4-1 large primaries with an awesome collector. Unlike the perrin/maddad equals it makes power all the way to redline. I am not trying to knock the header... its good for sub 350hp cars. I would go Thermalogic, M2, TODA, GTspec, Agency Power, and then APS in that order as well.
Thanks for explaining. You and Scott were both discussing and my deaf self was trying to understand both of you and my brain went ????? Last night I've decided to not go rotated on the 2.5L. I think I'm going tdo6 20g or FP green with a mild cammed WRX head setup.
I only lost hp and tq after 6500. I usually shift by then. From 4500 to 6500 I gained a TON of TQ and some good hp. That means a lot in my opinion. When SS gets a break from his super busy schedule I'm hoping he will email me the dyno sheets I requested which I'm pretty sure he will
Googled thermalogic m2 and toda for Subaru headers didn't find much so any links would be appreiated. I assume they are all equal length?