devinbase

Just got a Redfire 03' SVT Cobra. Already have 2.75 pulley, diablosport programmer, shifter, exhaust, and k&n intake. Have driven a stick for a long time. Just wondering if there are any hints or tips from more advanced racers than i on how to bolster down all this horsepower at the line, what is the best rpms to shift at, double/power clutch?, what rpm to jump at? I have goodyear F1's, 285's, great tread left, just have a lot of trouble, after putting the pulley and programmer, from keeping the car straight, it keeps going sideways. Also, if any good mechanics out there can answer this question too- when i floor it , there is kind of a knocking sound coming from the engine, not like an engine knock, just something ive never heard before. I know it isnt the engine cuz it runs great, never makes that sound with normal driving, just when i mash the gas. Anything can help me at this time.

CobraSnake

i don't know what the knock is but i'd definately get it checked out. Unfornately you voided the warranty with all those mods.

RR03Cobra

The knock you hear can be deadly to your engine!! Especially if it's spark knock!! That is the number one reason for blown engines~~ Is your car dyno tuned? If not, I suggest getting a good tune in it before getting into boost, if not, you are risking on blowing the engine!! I believe in shifting around 5800-6000 rpm, that's when these cars are in full power, any more and the HP curve is dropping. You will definitely need drag radials to play! With a pulley and a proper tune, you HP should be around 450 to 480 rwhp and your rwtq. should be around 460-490. A regular street tire is not gonna hook up, no matter what kind of suspension parts you use. The only thing that will help your wheel hop and spinning is a good soft tire. Just p.m. me for more details on a good dyno tune and info. I would DEFINITELY stay out of the boost until you get it TUNED!

devinbase

Well see that was the thing, it almost isnt like its a knock, it is almost like the damned noise is a flapping sound, i dont really know how to describe it. I can almost for sure say it is not a knock, and it only happens at WOT. It sounds like back pressure or something, kinda sounds like the noise my friends old SRT 4 used to make, but not really the same. Has anyone heard of anything such as this? Oh and by the way, does the diablosport programmer's tune provide a sufficient tune? Thanks for any help

Dan04COBRA

What do you have for mufflers? Are you making the baffles rattle when you go WOT?

And no, using a handheld tuner in your driveway to tune your car with a pulley smaller than a 3.10 is asking for certain death. Your motor is going to be laying on your garage floor if you don't get a real tune.

devinbase

I dont understand. Why in the world would they sell those things if they are that inadequate. I thought they basically stepped up my car's computer's performance and tuning to compensate for the extra boost, what is it that the shop does, that the programmer doesnt? Please let me know some more.

mg01svt

Regarding the noise, check the belt, all plastic panels to see if they are loose. If you have a CAI check that it is not loose or knocking around.
Ensure the bearings in the idlers are spinning freely.

As others have said, if you are adding fuel through your handheld how do know you are adding enough. The life of your engine is worth way more than a couple hundred bucks for tuning. Do it right or you will kick yourself later.

Congrats on the new ride.

A