OSUGT Posted April 20, 2006 Report Share Posted April 20, 2006 Hey, guys. I just had Ford Racing Shortie headers installed on my 99 GT auto. Now I've got the headers, catless h-pipe, and 2.5in catback. I've noticed the car hesitates when you jump on it at low rpms. (Almost a sputter or something). At cruising speed it runs great. Could this be a backpressure issue? Is it possible to have air exit too quickly for a particular setup? All I have is an K/N intake, stock TB, and no power adder. Thanks in advance for the help. Jason Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted April 20, 2006 Report Share Posted April 20, 2006 Do you have a programmer? and or the O2 sims? Quote Link to comment Share on other sites More sharing options...
OSUGT Posted April 20, 2006 Author Report Share Posted April 20, 2006 No program on the car right now. Are o2 sims something like MILs? Thanks Quote Link to comment Share on other sites More sharing options...
s13 Posted April 21, 2006 Report Share Posted April 21, 2006 Only way to find out is put the original stuff back on. My car was sorta hesitant to move when I floored it untill I changed the fuel filter. Quote Link to comment Share on other sites More sharing options...
Tractor Posted April 22, 2006 Report Share Posted April 22, 2006 Not sure how true it is, but I've always heard that backpressure is accounted for in the stock programming and actually helps the cars performance. especially a nearly stock low HP engine. It would really help with the lower end of the rpm range. Of course I'm sure it opens up the HP in the top end, but thats not where your car spends most of its time anyway and that goes back to the stock programming comment. I know thats how it works on my 05 taco. So far there isn't really any exhaust system that improves it enough to make it worth doing. Evan Quote Link to comment Share on other sites More sharing options...
Lustalbert Posted April 22, 2006 Report Share Posted April 22, 2006 The larger tubes in the header probably do not maintain enough velocity at the lower RPMs to scavenge the exhaust out of the cyl, so part of it may be flowing back into the intake during the overlap of the cam. Once you have some RPMs, there is enough velocity to help draw out the exhaust so it wont backflow. Should not be a backpressure problem. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted April 22, 2006 Report Share Posted April 22, 2006 Only way to find out is put the original stuff back on. My car was sorta hesitant to move when I floored it untill I changed the fuel filter. That is NOT the only way, and is probably the worst way. You tune your car for the mods you add. Quote Link to comment Share on other sites More sharing options...
Razorback Posted April 22, 2006 Report Share Posted April 22, 2006 That is NOT the only way, and is probably the worst way. You tune your car for the mods you add. Yep yep. Get it tuned, especially with a full exhaust. Probably just running rich when you romp it or something. If anything the tuners will be able to look at it when it goes wide open throttle and they'll be able to tell you exactly what's happening when it sputters. Quote Link to comment Share on other sites More sharing options...
OSUGT Posted April 24, 2006 Author Report Share Posted April 24, 2006 Thanks for the thoughts, nurk and razor. I've had a hypertech programmer since I got my gears and wheels. I installed the timing program yesterday and it seems to be running better but not 100%. Any idea where to get a tune? Thanks Quote Link to comment Share on other sites More sharing options...
Buckeye1647545503 Posted April 24, 2006 Report Share Posted April 24, 2006 I just saw this Jason sorry Ya I would say takeing it to http://www.dynotunemotorsports.com/ and let brain chip it would be a great idea Quote Link to comment Share on other sites More sharing options...
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