Ran my car two weeks ago. it was hot and humid. 86 degrees and 80% humidity. Elevation aroun 700ft.
specs then:
EGR and A.I.R. deleted.
Lid with K&N filter
SY3500 converter
Hooker long tube headers, Off road Y pipe, hooker aerochamber muffler
BMR SFCs
Lakewood LCAs
3.42 gears
3750lbs with driver.

I ran 12.9 at 106.47

Since then I installed:
GTP 420 cam (226/226 .595/.595)
Comp 918 springs
36# injectors
comp pushrods
SSRA

I dyno'd (on a mustang dyno) at less than 300hp! Tuned the car with ls1 edit, and picked up about 10hp before my laptop died.

Ran it last night in 50 degree air, 70% humidity, and roughly similar elevation.

Car went a best of 12.81 at 107.5. This was after a lot of logging and tuning through the course of the night. I picked up 1mph and dropped less than a tenth off the ET.

What gives? How can I gain NOTHING from those mods? I know I need more converter, which will help my track times, but why are the dyno numbers so low with all the stuff I've done? I tihnk I am getting pretty close on the tuning, but it seems like I should be a good 50hp higher than what I am...and I know there's not THAT much left in tuning (like I said, I logged the runs so I know how it's running now)

 

I feel your pain man.

My previous best was 13.538@105.01 w/2.2 60' with my lid and old Magnaflow muffler in 80 degree weather.

Yesterday I ran my car for the first time since I installed my Rumbler and y-pipe. I was hoping for a 13.3 with the same 2.2, but instead got the time in my sig. by improving my 60' to a 2.1, leading me to believe that my new cat-back and y-pipe didn't improve my performance at all.

I'm gonna run again in freezing cold weather and hopefully wind out a better time.

 

Mike,
How much preload is on the lifters? If the cam has a different base circle than stock you could be light on preload and not opening the valves all the way.

 

they are stock rockers. they're torqued, not set for preload.

 

Mike even with the stock rockers and lifters, when you put a cam in you need to check the preload. You do this by bringing number 1 to top dead center and loosen the rockers completely. Then screw the bolts in till you have zero clearance between the rocker, valve stem, and pushrod. From that point measure how many degrees you can turn the bolts before the rocker pedestal contacts the head. Using the pitch of the bolt you can then determine how much preload you have. I can't remember the amount of rotation off the top of my head but the preload has to be between .020 and .040". If it isn't within these specs then you'll need different length pushrods or adjustable rockers.

 

not to mention..

with some cars, messed up cam timing can screw up your valve stems.

If the valves are opening at the wrong time, you could have valves bouncing off of pistons.

 

I don't think it's cam timing. This thing pulls to 7k with no float or noise.

 

36 lb injectors sound like a little over kill. Did you happen to pull any spark plugs and read them? Probably on the rich side I would suspect.