Yes, they delete the "butterflies" in the stock intake manifold which are prone to breaking off and ****ing up your engine. I'm not 100% but I think people see peak gains of about 5-8hp from them. You must get a custom tune for it aswell.
Ok I've never heard of the butterfly valves breaking off and damaging a motor. But you are right about the gains and a tune being required if you delete them. The delete plates remove the butterfly valves in the intake runners this allows for more unobstructed airflow. This is a good mod for people that race their car a lot or have more aggressive mods done, like cams or a S/C. The purpose of the butterfly valves is to increase the air flows velocity at low RPM's to give better torque and a more linear torque curve. This is why i think they are better for more heavily modded cars then just a Stang with a CAI and exhaust. While giving you a few more ponies up on the top end you will lose some torque down low and because of that it isn't for everyone.
you will not lose any torque down low, you will actually gain torque and horsepower across the entire rpm range provided you have a tuner who knows what they are doing. and for the broken butterfly valves, here ya go..........scary stuff!! lower et with delete plates?? - Page 2 - WWW.S197FORUM.COM -J
Wow, thanks for sharing that i've never seen that before and your right that is scary. It makes me wonder though they guy didnt elaborate on what exactly happened just showed a pic. The tune is important with going with the delete plates and it can make or break how much improvement you get with it, but thats kind of the case with any tune.
my bad, he did elaborate on another thread. Run a search on s197forum.com and I'm sure it'll turn up -J
