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Old 05-31-2009, 01:14 PM   #27
Scooby Specialist
Member#: 4498
Join Date: Feb 2001
Chapter/Region: NWIC
Location: Portland, Oregon
WRX H6-3.0 Turbo


Originally Posted by Phatron View Post
If you could make more power with more boost, then you cant call it an aggressive tune

13 whp at redline is nothing to sneeze at.

Also, if you really look at the data you'll notice that the boost is actually lower with the Cosi manifold and it was also richer and still making more power.

the manifold also "unoptimized" your setup. Before you were peaking at 6200rpm which allowed you to stay in the meat of the powerband by shifting at redline.....where as now you are leaving power on the table unless you're gonna rev to 8000rpm.

I'd really like to see how far that slope carries out. almost looks like the hp peak would be 7000-7200 rpm now.

Seems like this is a mod where you're gonna need a huge turbo that causes the intake manifold to become the restriction, but once you get rid of that restriction you're gonna need a valvetrain to take advantage of your newfound powerband.
LOL.. Agreed.. but of course one mans agressive is another mans engine rebuild. I did do a few more runs with a bit more boost on the cosworth manifold. I'll posts a few of those up as well. They made more power, but were not stable run to run (knock that is). This is pump 92 octane, and I have discovered that on the dyno with the right conditions I can make better power then will run on the street day in/day out. In the 5500-7000 range, my 08 gains about 10whp with a degree or so, but on the street that degree is too much. I suppose I consider a 'tune' agresssive before I consider a 'run' agressive.

Indeed what Ed said, and you as well is very true.. this is an unoptimized setup for this manifold. Part of this test was to see how well it worked at 'lower' power levels.. if you call 390-400whp low.

Sure enough at a bit more boost the upper end came alive more. I am sure that with an agressive race fuel tune more upper end power, especially near 7k, can be had.

For me it was instructive to first see a bit of the lower limits of where this part might come into play. Our next step (this week) is to get a solid tune on Tim's STI (35R, 8k RPM), then swap in a Cosworth manifold. I suspect we can make some good gains.

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