Originally Posted by jason miller
MAPerformance, or whatever it is, made just about 400 on a dynojet with an hta and e85. I think that was at either 26 or 28 psi. JSarv made just over 400 on an airboy plot with a regular 18g and e85 right before his car got totaled. I believe that was a 28-29 psi run with front mount, and he had previously been making 360-370ish on an sti tmic and (I think) 26ish psi. That was with an 8cm exhaust housing, which made more hp over the 7cm throughout his entire rpm range.
Really, the stock ej205 heads/cams aren't designed to make a lot of top end. Pretty much any setup is going to taper a bit up top, unless you're running such a big turbo that it's not fully spooling until almost redline.
Take MAPerformance's numbers with a grain of salt. He was running on 800cc injectors and the stock intercooler at 28psi. Somehow, that math doesn't compute for me. Until that's backed up by another company, I think it's simply the dyno.
I think that 68hta would be ideal with a 8cm td06 option, it would be out powering 20g's all day. Until that happens, it's kind of a missmash of parts that work ok. There was one thread on here with a guy who gained 30whp by switching to a 10cm2 hotside on his, of course he was running a 2.1 stroker to 8k with headwork (still dropped massive power by 8k though).