I was just wondering why my throttle response is becoming less than it was before. I recently got new 4-1 headers installed on my n/a si that already had I/E installed. Now for some reason when i push in the throttle there is little response for the first inch or so on the pedal, but the rpms are still climbing and the vac guage is showing increased pressure too, but theres no pull. I was thinking its the clutch, but i realized it cant be it cuz the clutch isnt engaged when this is happening.

 

with i/h/e your increasing your top end hp, while sacraficing a lil low to mid- range also what size is the piping?

you may be losing back pressure from too large a piping or something like that

 

with youer intake,header,exhaust setup you lost low end tourqe..sell all your parts and buy parts that will make low to mid power with ok top end

 

im running a aem CAI, an n1 2.5" cat, and dc 4-1 headers, i think i did lose some low end hp, but ive been told that you cant lose torque. hp= amount of work engine can do in a period of time/ torque = amount of total work an engine can do.

 

Horsepower is a function of torque. Ever wonder why a dyno sheet should always show the same output between hp and torque at 5252 RPMs? Maybe a better way to think about it is that you are losing low end power. Your setup is made for top end. Don't worry about the sacrifice of power at the cruising RPM range.

 

2.5" is kinda large for an all motor app.

 

i got the 2.5" cuz i knew i'm getting f/i so i wouldn't have to but new pipes after the cat.

 

its the 4-1 header..should get a 4-2-1 header with a 2.5 collector that will move the power to the low end a little more

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grip &raquo;</TD></TR><TR><TD CLASS="quote">its the 4-1 header..should get a 4-2-1 header with a 2.5 collector that will move the power to the low end a little more</TD></TR></TABLE>

i agree

 

Indeed what I was about to say. The 4-1 header and 2.5" exhaust is definitely made for continuously high revving motors, not really for street use. 4-2-1 with the 2.5" collector as Grip said would work out a lot better.