Questions about '03 Cobra

Discussion in 'SVT Tech Forum' started by tlrdynes, Jan 28, 2006.

  1. Hi all,
    I am about to purchase an '03 Sonic Blue Cobra coupe private party. It is mostly stock. The owner has some uninstalled items he will throw in with the deal (benefits of a Military to Military handshake and smile deal). The car is very clean and very well maintained and I will run a carfax on it when I get the VIN. I have searched the forums and have not found out some basic info on the '03 Cobra.
    What are the stock injector sizes?
    What is the stock gear ratio?3.55?
    What is the stock upper pulley size?
    Will any mustang 8.8 ring and pinion fit in a Cobra IRS diff?
    What can the stock fuel pump handle/what is its rating/are there one or two?
    What size is the stock MAF and does it need to be larger for upped boost/injectors?(personal experiences on this one)
    Will the stock computer safely let the car run more boost with an aftermarket exhaust or will it go lean?
    Is the Kenne Bell Boost a Pump a solid add on or a waste of time?

    Sorry for all the questions, thanks for any answers you all might be able to lend me.

  2. Welcome to the forums and congratulations on the new acquisition. You'll love your new Cobra!
    There are two pumps in the Cobra tank and they are rated at a combined total flow of 238lph.
    Stock MAF is 90MM. You do NOT need to go with a larger MAF on this car, just better MAF electronics. STAY AWAY from larger MAF housings!!!! Makes tuning the car VERY difficult.
    Hmmm... adding an exhaust usually reduces the overall boost level a little and the car is bone stock form is pig rich from the factory, so no problem there....but if you add a smaller SC pulley then YES< you ABSOLUTELY need to get the car tuned to ensure a safe A/F ratio.
    It's an effective means of increasing fuel flow utilizing the stock fuel system components. It works as designed and can help increase pressure and flow when you need it most preventing the car from going lean. Unless your car is starving for fuel though (somewhere around 500RWHP using stock injectors, MAF, pumps) there's no need to get the BAP.
    Sounds like you are ready to just jump right in and start modding the crap out of this car. Would you mind divulging your plans to us? We may be able to steer you in a better direction and save you a lot of time, money, and trouble if you tell us first what it is you're wanting to do with this car. Are you looking for a fast corner carver? A straight line car? A street brawler? How much horsepower do you want?

    Here's a great link to a FAQ that will answer many of your standard 03/04 Cobra questions if you have any others...

  3. Thanks UM for the quick response, the info, and the link to the info page you provided. I don't have the car yet so I don't know all the specs and can't go out to my garage and just look, so this forum is invaluable. I don't have plans of modding the crap out of it. Truth is I like the '03 mostly as is. No one can deny that Ford engineered the car for much more than what it came stock with and so the car can safely handle the extra umph. The car I'm looking at already has BBK longtubes, Magnaflow catless x-pipe, and Magnaflow catback installed, thus the ?'s on exhaust on this specific car. I'm not a fan of the catless x-pipe, so I may try to find a catted one I can trade for. My intentions are a fun to drive car (got that as is) with somewhere between 450-500 hp at the crank. That should be easy from a car like this. I don't need a strip monster or a road racer, but I do enjoy trips up the canyons (military in AZ) :flag: on my ZX10R and have always dreamt of a car that could handle those roads. So, handling will be modestly addressed. The owner also installed a Steeda CAI, Billetflo(sp?) IRS brace, spec III clutch, and a few other small things. A stock sized quick change upper is already installed with a 2.93 sitting in the trunk along with a 4# quick change lower. I am not going to install either until I know for sure I can without damaging the engine. He also had the stock Eaton ported. Also in the trunk just waiting is the Kenne Bell Boost-A-Pump, so thank you for the info on that.
    My thought right now is to install just the upper and get some sort of a programmer that I can at least use a generic map with until I find a good shop for a custom tune. Then address the suspension with a few solid mods and call it a day. I do need some advice as to what all of you think is a good programmer, the Predator looks good but give me your opinions.
    Like I said, I'm not one to try to fix a good thing, but this car already has alot of quality parts installed so why not add the last few that come with it and be done with it? By what you said UM, the fuel system is pretty stout and should handle modest upgrades and the MAF is large enough for anything I'll ever need, I just didn't know the stock specs.
    Thanks again for your help.
    I hope I can help others on this forum like you have.

    P.S. I'm an F-16CG crew chief, so I am a total motorhead. Ahhh, I feel so at home in this forum.:nice:

    P.P.S. I have a set of 3.73's sitting in my garage I was going to use for my '95 Cobra driveline that I was going to put in my '68 Coupe.
  4. By the sounds of it I'm betting your car, if tuned properly, is already capable of putting down 450 without the upper or lower pulleys! My Cobra has similar mods as yours (minus the porting) and I'm making around 435 at the wheels. Adding the 2.93 pulley to your existing mods will definitely put your car very close to the magical 500RWHP level and then adding the 4lb lower will put you over. That upper & lower combo will be over-spinning the CRAP out of the blower though. There are plenty of guys out there doing that right now with great results, but you'll want to invest in a bunch of bigger/more efficient cooling mods if you decide to go that route. Plus you may need to get a new alternator pulley too because you may be over-spinning it with a larger lower pulley installed. These engines are pretty tough and can take a good amount of abuse, but I can't tell you what the long term results of running a 2.93 upper with a 4lb lower will be. I know that Eaton states our M112 blower is rated at 14,000RPM max. This is conservative according to most of the experts and they say the M112 can handle upwards of 16,000RPM for short durations. The stock pulley combo spins the blower up to 13,534RPM's when the engine is at it's 6500RPM max. Add a 2.93 in place of the stock upper and you're now spinning the blower at 16,860RPM's when the motor is at redline. That's almost a 25% overdrive. Now throw in a 4lb lower to go with the 2.93 upper and you're looking at 19078RPM's!!!!

    If it were me, I'd slap on the 2.93 and forget about the lower... Once you get up there around that 500RWHP level then you have to start worrying about bigger injectors, better pumps, BAP, different MAF, etc., etc., etc. I wonder why the original owner took the pulleys off in the first place? I wonder how badly the car has been beat on by the previous owner. With mods like that I'm sure it's seen a fair amount of abuse. Sure hope you're not buying a damaged car and not know it...

    If you do decide to get the car and you want to finish off the mods what you really need is a good SAFE tune to go with them. I have a Predator myself only because that was the only thing available when I bought my car, but if I were looking for a new handheld programmer today I'd go with the XCal2. The professional tuners prefer the XCal2 over the Predator because they are able to create a more detailed tune than what the Diablosport tuning software is capable of.

    If I were in your shoes I would give James from RWTD (Runnin' With The Devil) a call. If you provide him a COMPLETE & ACCURATE list of all your mods he will create you a killer custom tune, load the tune in an XCal2 or Predator tuner and ship it to you! All you do is "Flash" your ECM via the ODB II port and you're good to go! You would still want to get the car on a dyno with wide-band capability just to make sure the A/F is within safe limits, but the tunes James provides are usually 99% spot on the first time!

    All the information you need to know about James and his company can be found here:

    So I take it you're out at Luke huh? I was out there TDY a couple years back installing the new CAS (Combat Ammunition System). I'm a retired ammo troop myself.



    P.S. I know in Arizona you probably like to get out on the back roads and make some high speed runs on that ZX10R of yours! Word of warning, don't try making an extended high speed (150+MPH) run in the Cobra! More 03/04 Cobra motors have been damaged due to high speed extended runs than anything else! The cooling & oiling systems in these cars can not handle extended runs like that without some serious upgrades.
  5. I have read about the max RPMs on the Eaton, and about needing fuel upgrades above 500hp. That's why IMHO more than 450-500hp is excess on a street Cobra, especially if that's RWHP. One thing I also read, on Kenne Bell's web site of all places, is that the max rpm rating on the stock blower is more likely due to inefficiency than fear of breakage. The stock simply doesn't flow enough to maintain 14+psi from low rpms all the way to max engine rpm like it can with 8psi. The stock blower drops off alot toward the upper engine rpms when running more and more boost, the more boost you run, the more it drops off. However, if the stock blower is ported it will flow substanially more air and you will not experience such a drop off at upper rpms. So you may be safe to run a bit above the recommended max rpm, not that I really want to. Just food for thought.:nice:

    Awesome info on the tuner. I have only used the Predator on my friends Lightning and it is nice, but I haven't seen the XCal2, I'll check it out.

    I understand your concern about the mods on the car. The TSgt I'm buying it from just bought the car. He hasn't even had it long enough to get the plate in the mail. He bought it as a completely stock Cobra from the original owner in Las Vegas, and it is in awesome shape. I like things mostly stock, and this TSgt is obviously not like me in that regard. First thing he did was put the exhaust on and CAI with brand new Nittos in the back, along with sending the Eaton out for porting. I believe he drove it hard but I know he didn't abuse it outright, at least not any more than what these cars can handle.:nice: He is now selling it because he's getting a new GT500, that lucky [email protected]#$. So I trust him, and this car, but thanks for the concern. I also have the complete CARFAX and it's clean. One concern of mine, I started it up the other night with him there and it was cold out. It idled well, but if you turned on the headlights or rolled the windows up or down the idle seemed to drop quite a bit IMO. Like I said before, no cats and no MIL correctors yet, so this may cause something like a weak idle, but I'm still looking into it. I am going to test drive it tomorrow, so I'll let you know.

    I don't plan on any extended high speed runs, but thanks for the great info on that. I never would have known. Most people drag these cars so that is probably a little known fact. I'll definitely look into oil sys upgrades if I go road racing.

    :flag: Thanks for serving, if you're ever at Luke look me up. I'll show you my jet, talk about thrust, 03 Cobra ain't got nuthin on an F-16!:hail2: "If you ain't ammo, you ain't *****" :nice:

    Thanks again!
  6. The links on RWTD's website for the SCT aren't working. Do you know what he charges for the tuner and the custom tune shipped?
    Much appreciated.
  7. How the HELL does a TSgt afford a GT500!? Must be living in the dorm with no bills/no life or his wife has a killer job!

    Sounds like you've been doing your research! Do you know whether you have an "Apten" port job on your blower or a "Stiegemeier" port? Technically both of these were done by the same shop, it's a matter of what "Stage" porting has been done. The latest is a Stage IV and coupled with the right pulley set up it can create and hold 16-18lbs of boost right up to redline! You can read more about the porting here:

    As for contacting James at RWTD... best thing is to just call their shop. They have many different packages available, you can even get one where he will provide tunes for the life of the car!!!!

    They just started carrying the XCal2's and his website needs to be updated for sure! Call their sales dept at: (251) 479-9451

  8. You know you're a motorhead when you're already plotting before you even take delivery on a car!:nice:

    His wife has an awesome job, she's the one wanting him to get the GT500! Military isn't that bad anyway, my wife and I do ok with the right budgeting and savings plans. That's the key, look forward to the future, not just the now.

    I'll give James a call as soon as I can, see what he can set up for me. Thanks for the number.