How much HP gain?

Last night I was driving over to Blockbuster with my girl to rent a movie. Well, on the way I was waiting for a light to turn green when another Si stopped next to my and started to rev his engine. It looked like it was bone stock Si because it didn't sound like he had a exhaust or intake. As we raced, it was pretty even until about 5,000 rpm in 2nd gear and then I started to pull ahead. At about 80 mph, I was 2/3 car lenght ahead and had to slow down because there was a car in front of us. My question is, how much HP gain do you think I have over a stock Si. All I have right now is a Greddy Evo Cat-Back. I know driving skills also come into the factor but I just wanted to know how much HP my exhaust would make.:)

Greddy Evo. I like that exhaust. anyway, an exhaust by it self wouldn't make that much of a difference. maybe 5-8 HP. It prolly had more to dowith the shifting.

prolly around 5hp at most

You can most likely drive better than him :D

yeah, I'm thinkin no more than 7 or 8. Get a CAI and a header and you'll be handing si's their asses all day.

just about all catbacks are good for no more than about 5 to the wheels...i attribute ur 2/3 car lengths on him to about 1/2 a car length from the exhaust and the rest due to him prolly not punching it as hard as u did. thats what i hate about pick up street races....u might race ur arse off, and then the other guy lets off after 2nd gear....or someone might pick wit a race with u and then u screw with him for a gear or 2 and then let off...the only true test is at the track when everyone is racing to their full potential to get that best time
:bandit:

Originally posted by craz_e_99
thats what i hate about pick up street races....u might race ur arse off, and then the other guy lets off after 2nd gear....or someone might pick wit a race with u and then u screw with him for a gear or 2 and then let off...the only true test is at the track when everyone is racing to their full potential to get that best time
:bandit: good point

Originally posted by kicker1_solo
good point

THANK U THANK U!!! its the truth though...u know how it is out on the streets
:smoka: