View Full Version : New Guy with general questions re: S/C

03-16-2003, 09:28 PM
I've just purchased one of these potent cars, and am wondering about a few things I've noticed....
1) I get a gravely sounding, rumbling noise (my best description I can think of) out of the engine compartment around 2500 rpm up to the point where the S/C kicks in. Is this normal, or is there a bearing in the S/C that needs some first aid? Could it be a clutch mechanism noise from the S/C?? (I'm a s/c dunce, so please excuse any dumb questions prior to this, or after this disclaimer!)

2) I'm prepping for an upper pulley change, and if I do, I'd assume the noise would occur even earlier in the RPM range...true?

3) Looks as though you'd want to do all your mods prior to chipping the car, to include all the changes in the performance chip. Do exhaust and intake upgrades also require a re-burn of a chip?

Thanks in advance for the help...your forum has really opened my eyes as to where to put my money and time.


03-17-2003, 08:51 AM
1, If you are getting a noise that you think is coming from the supercharger, have it looked at before you start modding the car. Ford is just looking for ways to void warranties, and chances are they will not do anything for you once a pully is installed.
btw: The supercharger is running all the time, it doesn't have boost when you are just light on the throttle, but it is always running.

2, See above

3, Any pully 3.10" or smaller should have a chip burned to compensate the a/f ratio. It has been reported that the 03's are very lean in the midrange, don't take any chances.
I wouldn't worry about the chip for just a cai kit or exhaust, but if you are going to bump the boost alot, deffiantely don't wait with the chip. :thumbsup:

03-19-2003, 06:31 AM
Cobra R is correct. The blower will start making boost well before 2500 rpm with enough throttle. Under light throttle the engine is actually pulling vacuum. You could see it if you had an aftermarket boost gauge with an Hg side. Take it back to the dealer. I really don't know what kind of sound you could be hearing. A cammer motor makes a lot of noises.

03-19-2003, 11:57 AM
Gravely rumbling sound... I'd almost say, from the way you described the sound, that maybe you were in 2nd-6th at too low an RPM, but if you say its going on upwards of 2500, then I agree with the rest, you should get it checked out.

03-20-2003, 11:25 PM
Thanks for the info!
I definitely think a trip to the dealer is in order, just to see.
No modding prior the fix, if there is one.
As for the " too low" RPM, 2nd-6th gear, I don't think I'm bogging it. It usually shows up over the 2000 rpm range, when I'm not asking much of the engine, just cruising around 80mph or above.

Now...if you'l entertain them, a couple of other questions:
1) The car has just died a few times, usually when coming to a stop. The car was out of gear, and just coasting to a stop when the engine died. It can also idle a bit rough at times. I saw someone else had this problem, in a prior post....Has someone actually had this problem resloved? What is the deal with this?

2)The vibration at 80 mph.....Is it jus a matter of bad balancing or alignment...what's the fix for this little annoyance?

Thanks again!

03-21-2003, 07:43 AM

There is a "fix" for the idling problem, just take it to the dealership. AS for the "vibe" at 80 mph, that's an indexing problem of the driveshaft. Again, the dealership should be able to fix it for you. Sounds like you need to take a trip to Mr Blue Oval. :doubt:

03-21-2003, 05:22 PM
Unless something new has come out within the last month or so, Fords "fix" (computer reflash) hasn't been much help to the stalling problem.(it may have helped a few cars, but not most of them) My car has stalled 3 times in 174 miles and it has the new program in it.
Some people have had success adjusting the iac valve, I am going to try and mess with that when the car comes out of storage. It certainly is an annoying problem.

03-21-2003, 05:38 PM
something worth trying... clean the MAF sensor. very easy to do and fixed the problem in a few cars with the stalling issue.


03-22-2003, 12:07 PM
Should the MAF be that dirty in 1000 miles, or has it come contaminated from the factory? I'll give it a try, no matter what....

As for the driveshaft, my '94 Z-28 came with a severe vibration around 115 mph. The dealership was nice enough to replace it with the aluminum variety!

Thanks again, as I continue to work out the kinks!


03-24-2003, 01:11 PM
If you have an aftermarket filter or CAI then someitmes excess oil from the filter element can get on the sensor and cause little things to stick. One person had found a little plastic shaving that was stuck to the sensor after installing a CAI kit. This was causing his car to intermitantly stall.

Best of luck to you :thumbsup:

03-24-2003, 10:59 PM
Thanks again....
Figure the Ford folks will get first whack at it, in the next few days.
The stalling problem seems to be getting more frequent, with no alterations to the car, to date.

I'll let y'all know how many of these bugaboos disappear after my dealership visit.


04-05-2003, 11:54 PM
I had the stall problem happen to me as well once, but I figured it was just a freak occurance... Since it only has happened once, I'm not sure if I want the guys at the dealership touching the thing until it becomes a problem. I also seem to be suffering from the "tick". I took it to the dealer and after 3-4 days they still could not seem to fix problem AND it had 20+ more miles on it than it had when it went in! :mad: Make sure you let them know you watch the mileage if you are going to Northside.

04-08-2003, 11:03 AM
Well, Here's what the folks at Northside Ford said and did with the problems:

1) 80 MPH vibration: balanced the tires, and found the left front "out of round", meaning the tire needs to be replaced. Of course the F1 tires are out of stock, and on back order, so I wait for a call back. Since the tech moved it to the rear wheel, the vibration has practically disappeared. The equipment they used was new, and puts a load on the tire as it spins, and senses any deformation the the tire. Cool stuff, and I highly suggest anyone who has a vibe should ask if their delaer has this machine.

2) Stalling: They reset the "idle strategy" by removing power to the computer for some duration of time (a post on this is else where in the forum), but it did nothing for the stalling problem. Has stalled twice in the last week since it was reset. I know it takes a while for the computer to learn the car, again, but I think more than 250 miles had passed, and it's still dying!

3) The "gravely" bearing type sound: Said it was quieter than most, so I guess it's normal. Still looking for a ride in another couple of 03 Cobra's to confirm this, though...

Here's the scoop on what San Antonio doen't like as far as mods:
Everything I wanted was fair game, except a pulley (and the associated chip). The service manager said he could probably sneak it by, if I didn't want to have to remove the pulley (pressed on), since it could hurt the SC to keep yanking on the shaft to do multiple swap outs.

The stuff he said was no prob: Headers, shifter, exhaust, cold air (though he said the CAI with a bend in it too close to the MAF was making some Cobras act wierd...computer messing up fuel delivery, etc, because air wasn't flowing straight over sensor).

That's about it for now....any inputs as to headers and exhaust? The SVT tech said he would wait and buy the JDM product over the Bassani, and the like? Anyone else think JDM is the way to go? (supposedly cheaper, and much easier to install the headers)?


04-08-2003, 12:24 PM
Kooks are the best. These are the longtube ones that JDM sells for the 03.

the bassani mid-lengths are very very very hard to install. Whereas, the JDM (kooks) are only very very hard to install because each tube is installed independantly of the others.

Headers are just difficult to put in regardless of which ones you get.

04-08-2003, 07:56 PM
Well, it sounds like those guys at Northside are pretty cool about mods then. I have not talked with them about it, so that's good news.

As for mods, I was really starting to lean toward the Bassani exhaust without headers for now. The only reason I have not thought about headers is cause I had a lot of problems with some headers leaking that I had on a truck. Maybe it was just a freak or something.

As far as CAI, what do you guys recommend?

04-13-2003, 11:42 AM
So JDM has actually started selling the "Kooks"? I was told it was in the works, but not on the market, yet.

If I wanted to go the easy route, and do cat-back, or collector-back, I assume I'd miss about 80% of the power increase that headers would provide? Almost makes me want to go through the pain of installing the headers....

I've also had a leaky header on my AC cobra replica. Always afraid of valve damage from shock-cooling. Would this be a problem with the JDM prtoduct?

Thanks again....

04-13-2003, 09:58 PM
I think I know the noise you're talking about. Once you get the gear hooked up and clutch out, under that initially low RPM acceleration is where you're hearing it? I hear something in my car too. I've owned a 1995 Cobra R and a 2001 GT, and I believe I've heard it with those cars too.

I think it may be a Tremec transmission thing. However, if you think it's coming from the engine, I'd get it looked at.

04-14-2003, 01:58 PM
Originally posted by Cobra_Squared
So JDM has actually started selling the "Kooks"? I was told it was in the works, but not on the market, yet.

If I wanted to go the easy route, and do cat-back, or collector-back, I assume I'd miss about 80% of the power increase that headers would provide? Almost makes me want to go through the pain of installing the headers....

I've also had a leaky header on my AC cobra replica. Always afraid of valve damage from shock-cooling. Would this be a problem with the JDM prtoduct?

Thanks again....

JDM is currently selling the kooks headers. They are available in ceramic coating. But they will be releasing the stainless steel very soon.

I don't have headers, and I've been very happy with the performance my car is making. It sounds good too. I have the bassani x-pipe with cats removed and the bassani cat back. So far it has been the loudest thing on the road and sounds like it has long tubes.

I've also heard of a couple of people having some exhaust leak problems with the kooks but havn't heard of any valve damage reports. Id' think it could still happen though.

So, for now, I've decided not go go with headers. The gains would put me near 475+ rwhp but it's not worth the potential headache to me now. I would rather invest in a fresh set of tires.


04-15-2003, 02:05 PM
Here is a thread describing an exhaust leak issue that a few JDM/Kooks LT owners are having. :(

There was also a ceramic coating problem with the early batches of the LTs that were produced. They would get extreme rust and pealing when in harsh salt/winter climates. Supposedly corrected now though.

I'm beginning to think that the Bassani mid length headers might be a better way to go.


04-19-2003, 11:38 PM
Yea, I agree,
Headers might have to wait... I'll likely do a cat-back. I had a Z-28 I ran with Flowmaster cat-backs, and the noise was deafening! My nice Bose system thatt GM threw-in was always cranking to hear the tunes!

Is there a high-flow, low-noise option out there, that will minimize the advertising until you step on it, or are most the after market exhausts trying to get you noticed, even at a stoplight, or at low idle cruising?



05-13-2003, 12:15 PM
there is the Ford Racing FR500 exhaust. It is pretty quite until you stomp on it. It has flaps that keep the volume low until you give it the gas at which point the flap doors swing open. They flow pretty well too. And they even have an X-PIPE where the two pipes join just in front of the gas tank

05-27-2003, 06:36 PM

05-28-2003, 12:29 AM
The Ford Racing exhaust with the x-pipe after the exhaust sounds like the perfect match to me....quiet when you wnat 'em to be, and raucous when desired! Are the HP/torque numbers for the Ford system near what the "louder" systems are putting out, or do you sacrifice power for the stealth and "flap valve"?