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2003 Mustang GT, how much power am I making?

2K views 20 replies 8 participants last post by  dakine858 
#1 ·
Hey i was wondering if anybody knows what numbers to expect from these mods: 03 mustang gt ;c&l intake and plenium, intake spacer, 75 mm tb, pulleys, aluminum driveshaft, mangaflow catted x-pipe and mangaflow cat-back. These are my mods now i am getting silver racing spark plugs, msd coil pack, tb spacer, bbk shorty headers, and 30lb fuel injectors; can anybody tell me what kind of power all this might add to my rear wheels?
 
#4 ·
No chance of 300 or higher...maybe 260 with a perfect tune...you have to know the motor is rated at 260 bhp, take 10% off for drivetrain loss and you are starting at around 235rwhp...now add your mods and 25-30hp would be expected
Also you don't need bigger injectors, save your money until you get a blower. Use those extra funds to buy long tube headers instead of worthless shorties
 
#6 ·
The only way to know for sure, is to put it on a dyno. I've been doing this for forty plus years, and if you had the motor dynoed and new what it made with those mods being used on the dyno. There's a formula that you would use, take the number that you're making on the dyno at the crank and multiply by .85 and that would give you the number that you are making at the wheels. But you need to know at least one of the numbers, like if you were making 350 HP at the wheels and wanted to know what the motor was making you would divide 350 by .85 and it would give you 411.764 so just say 412 HP at the crank. You can't make guess work, when it comes to HP you need to put it on the dyno. As for the 30lb. injectors, don't waste your money. For the mods you have added, you won't need them because you won't make that kind of HP without heads, cams, and intake if you make it. Before changing your injectors, have it dynoed and tuned. If you need to change at all, the most you would need is a 24lb. injector. You won't gain any power, bye changing your injectors. Injectors are rated for HP, most injector MFG's have a chart as to what size injector you'll need depending on the HP you're making. With the mods you have installed, you'll be lucky to be at 300 - 310HP at the crank. And if that's the case then go to 24lb. injectors not 30lb.. But have it dynoed and tuned, so you know where all your parameters are set and what you have gained. You're in for a big learning experience, Mike. :nono::nono:
 
#7 ·
Im going to guess you might be making 250 or so, there is no real way to tell except put it on the Dyno. Read my mods and I make 312 RWHP. so Im almost sure you are not going to make 300 and up....
 
#11 ·
If I'm not mistaken, Zukman put down the 312 w/o the nitrous. I was surprised as well. That's impressive for those mods.

OP- I'm gonna tell you the same things that other members did, but I'll phrase it differently...Injectors don't MAKE more horsepower, they merely SUPPORT it. With your planned mods, you're flushing $$$ down the toilet by buying them.

Also, the MSD COPs arent' going to help you out any. The OEM ones are more than adequate for your mods, so save some cash by not purchasing those.

Throttle body spacers are generally accepted to be pieces of garbage as well, and really...most people will tell you that shorty headers suck, too. Especially BBK. I understand your reasoning for wanting to use shorties, but longtubes are better unless you you have a power-adder and then you might see some gains out of shorties.

You're choosing your mods like a newbie, and that's ok, because you might be one. Do some research and ask questions and you'll learn stuff that will save you money and headaches down the road.

As for mods you could do...Other members already mentioned cams, heads, and a shot of NOS. Given your list of planned mods, these may be out of your price range. You've got to pay a significant amount of cashmoney to get 300+ hp to the rear wheels in these cars. Trust us...we know all too well, and I personally am scared to add up all the receipts for the mods on my car.

The good news is that you have other options. You can make the power you have now more useable...Doing a gear swap to 3.73's or 4.10s is one of the best mods out there.
You can also add subframe connectors to stiffen up the chasis, and springs plus shocks/struts will have that car handling better than you ever imagined.

The bottom line is that a few bolt ons aren't gonna get you 300 hp. I wish it were that easy.

Good luck.
 
#16 ·
maximum motorsports makes the best...it costs the most too...go figure...Steeda makes good stuff, there are lots of other options, just shop around...it also makes alot more sense to build a foundation for any power adders you may buy in the future...I can't tell you how many 500hp cars I see at my tuner's shop that have no suspension, brake upgrades and they drive like total crap...they are like missles with no fins.
 
#14 ·
Subframe connectors. These will stiffen the chasis and prevent flex. There are two types, bolt-in and weld-in. Weld in is preferable, but obviously must be welded in. Most people don't have the means to do that so you may have to pay someone to install them. They're fairly inexpensive, my guess at the average cost to buy them would be around $150 depending upon brand.

Lower control arms. The stock ones suck. There are also a billion different brands of these, and some are adjustable for ride height. Pretty easy to install. These will help with wheel hop, and allow you to put more power to the ground.

Springs will lower your car if you want, and make the car look, ride, and handle a lot better. The problem with springs is that often, you must also upgrade your shocks/struts to match the springs, because aftermarket springs usually have higher spring rates that the OEM struts/shocks can't support. Lowering the car also usually means that you'll need Caster/Camber plates to properly align the car. Some people get away with not needing them, though.

Those are a few ideas. I'd research brands like Steeda, and Maximum Motorsports. I personally go with MM for all my suspension mods. Their customer service rocks, and they know what the hell they're talking about.

As I stated earlier, do some research on your own (Google is pretty nifty) and narrow down your choices/ideas. Then come back and hit us up with more questions or find out what others are using that works well.
You can't go wrong with suspension mods. All the power in the world isn't worth **** if you can't steer it properly.
 
#19 ·
312 RWHP on my car was straight motor, during myrtle beach mustang week tuned by Dan at Pro Dyno. I am running a Zex wet kit and play around anywhere from 75 to 125. I am having a small fuel problem now but it should be fixed within a week or so. The Comp Cams and Valve train kit made the biggest differance I have done after Dan tuned it. The Cams made the car pull like a beast.. I love it...
 
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