Kjewer1
Well-Known Member
- Thread starter
- #61
Power may be PCM controlled and limited in stock form, but the whole point of tuning the thing is to get around all that. The only limiters my engine is subject to are the ones I want in place.
Freeing up the exhaust will still reduce back pressure at a given boost, which increases VE and reduces pumping losses. You can see the VE change in the logs if you know what you are looking for. I've created a number of math channels that show me things you wouldn't see with just the normal Cobb/Ford parameters which are also very helpful.
The gains are fairly small though. With my car in the 11.9s, dropping the catback (open 3" downpipe) is only worth 10 hp, 380s to 390s. That should be worth a tenth in the quarter but I struggle to even find that much. This is mostly because back pressure really isn't bad on these things in stock form. A 2:1 back pressure to boost ratio isn't terrible. I've run much higher. In fact now that I think about it, when I set the record for the EVO3 16g turbo on my car it was at the same back pressure to boost ratio the Mustang runs.
To give a more extreme example from my Talon just because I have the numbers memorized, the difference between 55 psi boost and 80 psi back pressure, and 55 psi boost and 36 psi back pressure, is 5% VE, and somewhere around 30 hp in pumping losses (estimated). The gains are bound to be less on the Mustang at a fraction of the boost and HP.
Freeing up the exhaust will still reduce back pressure at a given boost, which increases VE and reduces pumping losses. You can see the VE change in the logs if you know what you are looking for. I've created a number of math channels that show me things you wouldn't see with just the normal Cobb/Ford parameters which are also very helpful.
The gains are fairly small though. With my car in the 11.9s, dropping the catback (open 3" downpipe) is only worth 10 hp, 380s to 390s. That should be worth a tenth in the quarter but I struggle to even find that much. This is mostly because back pressure really isn't bad on these things in stock form. A 2:1 back pressure to boost ratio isn't terrible. I've run much higher. In fact now that I think about it, when I set the record for the EVO3 16g turbo on my car it was at the same back pressure to boost ratio the Mustang runs.
To give a more extreme example from my Talon just because I have the numbers memorized, the difference between 55 psi boost and 80 psi back pressure, and 55 psi boost and 36 psi back pressure, is 5% VE, and somewhere around 30 hp in pumping losses (estimated). The gains are bound to be less on the Mustang at a fraction of the boost and HP.
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HP is 390, but torque I've seen up to 475 if I really load it up down low. I did find 75 whp at 3000-3500 which I really hoped would improve the 60 foot, but I never did get it to materialize. It still runs in the high 1.5s. At this point a transbrake would really come in handy... I should get back to racing this car again, it's been many months of just doing daily driver duties.
