GT Upgrade help.

My son has a 2002 GT , We have done several upgrades. X-Pipe with flow masters and left the converters. K&N filter removed the silencer, 3.73 Ford racing Gears. JMS performance chip, Pro-50 shifter, and aluminum drive shaft.Next we plan to install 70MM throtle body and cold air. I think this should have it to around 320 hp. Is this correct? And where would this run out on the track ( time and miles per hour ) can you give me a close guess.This is a daily driver and we do not want to go into the motor. Where should we go from here?

I'm only guessing because there are to many varibles (weight of car with the driver,  altitude, driver capability, etc. ) The car w/320h.p. should run about 13.2-13.4@102-105mph. Next thing to buy would be headers and if your willing N.O.S. or a supercharger.

X-Pipe with flow masters and left the converters.  Your car will be louder but exhaust alone will not give a huge hp gain. If later you decide to go with another power adder such as a supercharger you will see a benefit over stock but not in your curret setup. I would expect a 10-15hp gain

JMS performance chip. Again your going to gain a little but not much, especially for the cost in using premium gas. You migh wish to go for a 160deg thermostat

3.73 Ford racing Gears, Pro-50 shifter, and aluminum drive shaft. the drive shaft will free up some rotational weight but it wont affect your HP , neither will the shifter but combined they do help the car perform a bit better.

Next we plan to install 70MM throtle body and cold air. Your car came with a 70mm TB which is not as efficent as what your looking at but still flows quite well.

Test have shown many  cold air kit's are marginally better than stock with a quality airfilter such as a K&N.

 I think this should have it to around 320 hp. Is this correct? I own a 2002 Mustang and with no disrepect I think your a bit optimistic. I would suspect your HP is still in the 285-295 range.

Im not saying your doing this but its far to easy to get into the HP addition game. Part a gives 20% more, Part B gives 15hp, part C well you get my point

Be careful how a manufacture rates there HP gains, they may not be talking about peak HP gains and instead  a rating comparison at a RPM range where it showed a benefit.

 ( AKA My part willl give you a 15hp gain! what they may not say is there part shows a 15hp gain at 2900rpm andshould you use there part your peak HP may drop 12hp from stock) get my drift?

SInce your ready to spend some cash why not get underdrive pulleys and a ignition timing adjuster kit which willallow you to adjust your timing for best possible torque and peak hp

Moroso2 is right. 

Don't get caught up in advertised claims.  Read their dyno charts and look where the horsepower comes on.  5,000 rpm-6,000?  Did they lose 20 ft/pounds of torque under 2,000 rpm for that 15-20 top end horsepower?  Torque is what you want no matter what they say.  If you rev higher most engines will give you a few more hp for the revs.  Nice for advertising, not for your wallet.

As all the magazines say, an engine is an air pump.  More crammed in means more has to dump out.  But leaving one bottleneck in the path means you will not realize the potential of the 5 other parts you added.  For pre-99 cars it was the restrictive cylinder heads.

99 and up heads breath real well.  That is why you get the guestimated numbers of Moroso2.  Just look at what 96-97-98 engines make stock and you will see where your next step is going to take effort.

99 heads fixed the 4.6's major problem and made it a strong runner with reasonable torque.  Ford maximized the engine.  Now you want more from just tuning things.  Not going to happen I'm afraid.  What you are going to get is a twitchy launching car with deep gears and the same h.p. and torque within 10-15% of a stocker.

To get what you want.  A cheap 03' cobra, you are going to have to force induce some air or nitrous, add more fuel capacity and delivery, optimize your chip again and then see if you can launch your creation on the track while still driving to get groceries and not get pulled over for idiling to loud!

A lot of people would agree that beyond 300 h.p. with 4.6 liters is going to involve changing your Mustang into something totally different than what you drive right now.

Good Luck!

I hate to tell you, but I have to agree with everyone. I have an '03 GT with Bassani X-pipe & X-haust, Steeda pulleys, Pro-M 80mm mass-air, AFM Power-pipe, Accufab 70mm Throttle Body & Eibach Drop-kit w/ Steeda cast/cam plates w/ polyur... bushings & Mobil 1 Synthetic oil and obviously I'm running better than stock, but to be honest, I really cant feel that much of a difference and it's really making me mad. Part of it is the fact that I'm running an AUTO so I know I'm losing power there and my car has about 7k miles on it so the engine may not be used to the new parts yet?! also I don't have gears or a chip to tune it. I was wondering what you think of the chip you put on your car and how you like it. Also, I would definately recommend that you drop your GT if you haven't yet. Make sure you get poly-bushings though. It remarkable how much better launch you get from stock to lowered height. Not only that but it looks way better. Please let me know about your chip.

I don't understand something.  Why not go into the engine?  Just because it is a daily driver?  I had a '91 LX, ported heads, intake, Vortech, better clutch, exaust, cam, rear gears etc.  It ran low 12's@120, got 20 mpg on the highway and I drove it everyday.

I am just looking into buying a new Mustang.  After two kids, a dog and a house with a picket fence, it is about time to get back into it.  My debate is '04 Cobra convertible and leave it be vs a stock GT and I pull the engine to get it into the 11's.

With fuel injection and computer management, it'll run fine daily with better flowing heads and a performance cam.

I own a 00' GT and I have wanted to put headers on it, but I don't know  which company to go with. I also do all of my work myself, and I have never installed headers before....so if anyone knows any good websites/books/etc., that explain how to, I would greatly appreciate it...

AHHH!!!!! don't buy a 70mm throttle body anything above 65mm takes away from low end torque unless u plan on buying better fuel injectors then u can do it  

Im assuming that the 02 has 260 hp or something like that. The following mods might bring you up to around 290-300 hp. With the T. body and cold air intake will most likely get you 300-320hp you are looking for,full lenght header will help big time espeically in the upper RPM's. I would suggest the timming adjuster, this is alittle pricey but worth being able to adjust timming that little bit and you have 320 hp for sure with good tune up. If not wanting to get into the motor, as I dont blame you, and get all the suspension goodies you can. Upper and lower rear control arms with poly bushing, Energy Suspension should have a complete bushing kit that car which will make it more responsive in the handling department, subframe connectors should be a must with the control arms. All the power in the world wont do you any good if you cantget it to hook, period.  

Hey, why does a 70 mm Throttle Body reduce your low-end torque? Not questioning you, just curious. If you change your fuel injectors, wouldn't you have to recalibrate your Mass-air? What size fuel injectors would go good with a 70mm T.Body?  

a lot of manufacturers list that their product will add 10-20% more hp or whatever   this is only true about super fast cars on the strip  not for everyday drivers or street legal cars   so please dont always believe what you read  i guess your car might run high 13s to low 14s on street tires  

Go with a aluminum flywheel next. I run one on my daily driver 2000 Mustang GT(75mm Accufab throttle body and elbow, under drive pulleys,Diablosport tuner, AEM cold air kit, SLP x-pipe and Loud Mouth cat back) it made a huge difference in performance, and as long as you stick with a good street clutch( like a FMS cobra clutch) it's easy to drive in stop and go traffic. I can tell you from experience the cold air kit didn't make a noticeable difference. The exhaust was just barely noticeable., but the the Accufab 75mm throttle body/elbow made a huge difference as did the flywheel.