I just bought an '04 GT and started perusing the forums regarding the modifications I should start doing to enhance performance. I realized before I do anything, I REALLY need to learn about engines and how they work so I can understand the purpose of each mod. I don't want to just ask what mod to get, but rather I want to understand WHY it's important so I can mak an informed decision when I start investing.
Whew... that said, do you folks recommend a good site that gives an intoduction to engines, specifically Mustang engines would be better, so I can learn about them?
Check out the technical sections in the 4.6 section to start - if you run through some of the threads, you'll see lots of data.
If you have specific questions, feel free to ask.
It is a DEEP subject, really. Reading every Mustang mag (I recommend the old back issues from 2003 and 2004 of Muscle Mustangs and Fast Fords, or 5.0 Mag) you can lay your hands on will get you started. Better to do your research first, and buy later!
I can give you a brief overview. Your 04 GT is essentially identical to all 99 - 04 GT's. There are minor changes, but those are usually not problems.
The basic decision you need to make first is what direction to go with your build list. These are some of the broad options:
1. Naturally aspirated - low impact. This means no power adder (super charger, turbo charger or nitrous) and no cracking open the motor. This path can be limited to minor changes ("bolt on's") like cold air intakes, after cat exhaust systems, upper intake plenum and throttle body swaps, underdrive pulleys, with a nice aftermarket tuner thrown in for fun. I've done all these, and you'll spend about $400 on the after cats; $400 on the intake/tb duo; $200 on the CAI; $200 for the underdrive pulleys, and $400 on the tuner (SCT would be my current pick, though the Diablo is a fine item). Gears are the biggest change in this group. 3.73, 3.90 and 4.10's all have fans, and the decision depends on your sensitivity to cruising rpm's (the more gears you buy, the more revs you make at highway speeds) and gasoline consumption. Look to spend $500 to get high quality gears professionally installed. Boltons will NOT equate to the power gains from the other options below, though they can easily yield 10 or 20 hp.
2. Naturally aspirated - more ambitious. In this case, the simple bolt on route has not satisfied. Pulling heads and getting them ported and polished (machined by experts who will smooth and streamline the contours to enhance power and flow) will set you back about $750 for the machine work at a top quality shop, while some stronger Cams and Valve Springs with new retainers will set you back another $750 or so. Your GT motor has 2 camshafts (its a SOHC, "single overhead cam" design, and literally has a camshaft mounted in each head - older design OHV [overhead valve] motors used only one camshaft), and Cobras and Mach Ones have dohc (4 camshaft) designs. Altering the way the valves open and close can enhance power production as well. You can expect to realize about 40 additional horsepower from a nice streetable cam swap and a cleaned up set of heads. Price for all the parts and work is steep - $1750 for labor, and about $1000 for parts (you'll be adding new gaskets to the cost of the new camshafts, valve springs and retainers). People that go this far usually add an X pipe (replacing the stock H pipe) which (if cats are retained) will set you back another $400.
3. Naturally aspirated - serious. In this episode, you pull the whole motor and do everything in step 2, above, with more serious cam selections and going with a forged stroker kit for the block. What this means is that the crakshaft is replaced with a stouter unit that also has been desiged to compliment longer rods and unique pistons so that the displacement of the engine is enlarged. 4.9 or 5.0 liters can be had from the 4.6 stock size. This yields more power from the larger displacement, plus the more aggressive cams, though driveability and idle character will change. Money for some dyno time might be wise at this stage, as well. Call it about $2500 more than step 2. People who go this far almost always throw on some long tube headers at the same time - which will add another $1000 to the bill. Buy cerami coated ones if you do this - they will help create more power, and they block much of the heat (headers can be heat problems).
4. Centrifugal superchargers. The way to go with this is with a complete kit. Here's where it gets a bit confusing. If you went the initial route of a Cold Air Intake, Underdrive pulleys, etc, now is when you REMOVE those nice new items and put the oe items back on, because they will interfere with the function of the Supercharger! This is one reason I encourage folks to determine their path before buying such things! A good supercharger will yield MORE horsepower than the bolt-on-na routines in 1-3 above, and is really somewhat cheaper at about $5000 installed. Its perfectly possible to do the na engine enhancements and THEN add a supercharger, but its better if you KNOW during the na build that you are going to be adding a supercharger. This will influence gear and cam selections, for instance.
I'll come back and add more to this later - dinner is calling!
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tripleblack
"You can never be free until you let yourself go."
1998 3.8L, K&N air filter, Silencer removal, True dual exhaust flowmaster 40s. Two kicker 12s. Magnaflow X-pipe. Done with the v6, saving up for the LS1 this summer.
Thanks. That was a nice intro, and you hit just the point I was looking for... incrementally built, but not to overinvest in something I will undo later.
trippleblack, I want to commend you for taking the time and effort for your giving the new people some information and explanation of how to improve their Mustangs. Thanks from me, Good Job------- Chuck ,a very experienced old guy.
Good post 3B. You left out my personal favorite though.
5. Positive displacement superchargers. These are quite similar in the final product as the centrifugal superchargers as far as peak numbers and how they work overall. However it uses a different style of supercharger that 'pumps' air in a different which yields significantly different results. There is a mountain of power right off the line. They are however a good deal more expensive than the positive displacement superchargers for the most part though.
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Sometimes I think that government fits that old-fashioned definition of a baby: An alimentary canal with an appetite at one end and no sense of responsibility at the other.
- Ronald Reagan
Good post 3B. You left out my personal favorite though.
5. Positive displacement superchargers. These are quite similar in the final product as the centrifugal superchargers as far as peak numbers and how they work overall. However it uses a different style of supercharger that 'pumps' air in a different which yields significantly different results. There is a mountain of power right off the line. They are however a good deal more expensive than the positive displacement superchargers for the most part though.
Hey, I didn't get this fat not eating! I was gonna get to the Kenne Bells next.
How ya doin', Blue? How's that new job working out?
Anyway, you did cover #5 pretty good, though I think you mean "centrifugal superchargers" in that last sentence. A good install of a Kenne Bell twin screw will run about $6500 on these cars, while a VorTech (without cooler) can be had for closer to $4500. More power from the Kenne Bell and better driveability, though.
The centrifugal unit I'd suggest would be the ATI ProCharger, (has its own oil supply and does not require sucking hot oil from a pierced oil pan) which would be about $5500 installed.
Since the Kenne Bell's are about the most complete kits out there, I consider them better buys than virtually all the centrifugal kits, even though they do cost a bit more. Good value, and with their latest twin screw designs, very up-to-date. OE style install (similar to 03-04 Cobras), too.
6. Turbochargers. HP makes an excellent 50 size twin turbo kit that www.modularpowerhouse installs for about $8400. This is about the ultimate in power production for an unmolested stock 4.6. NOT a do-it-youself install, unless you're a VERY experienced mechanic! If you know you just won't be satisfied with anything less than 500 hp at the rear wheels, its a sure way to get you there (or much higher, if you elect to rebuid the block to take the strain).
Thanks for all the compliments - it helps me to do a brain dump like this ocassionally, just so the load is taken off the mods for a while! Payback for all the times I've lounged around AFM!
Any questions and let me know - if I don't know it, I know who does!
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tripleblack
"You can never be free until you let yourself go."
I just put this thread in my favorites. I'm definitely coming back when I get my '03 GT this spring...
NICE JOB!
You're welcome, for whatever I've contributed.
Just realized I left out Nitrous Oxide!
OK, imo nitrous is a neat add-on power adder for the person who wants a naturally aspirated motor 99% of the time - and the extra 100hp he can get from nitrous on the rare ocassion when the bottle is full, the track is clear, and its time to rumble.
Those who want that sort of added power in a street car or daily driver all the time should consider another path (chargers, turbos, or some serious N/A work) - inevitably, the bottle will be empty when you need it most, or your tune will be off and you'll detonate a motor, or you'll struggle with the various tunes needed for the motor when its On or OFF the squeeze.
Having been on all sides of this equation, I will say that if you do it, go wet (adding fuel AND NO2), not dry, and keep the tune sane. You would be well advised to get a switch chip (SCT makes a good one) or tuner so that you can switch back and forth between your normal tune and the nitrous version. Establishing that tune is something that is best left to an expert with a dyno, so count on some money ($300+) for dyno time, plus the chip ($250+) the wet nitrous kit ($800+), etc.
Nitrous has fans, and I have seen great results at the track with well-tuned cars.
I have also seen not-so-well-tuned cars thrill the fans with intake fragments exiting the hood scoop through holes the owner never intended!
They don't call it laughing gas for nothing.
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tripleblack
"You can never be free until you let yourself go."
While the answers provided are very well thought out and presented they neglected to ask you one very important question..... What is your experience level with engine work?
Look, you can do any number of things to your car. You can research each itme you wish to change or think you might want to. You have been provided some very comprehensive info as to how to go about it in steps. This kind of info is always helpful! these guys are some of the sharpest 9this forums members) I have seen about answering questions in a more information than you want fashion, and sometimes more is MUCH more. This is good.
Listen closely to these guys. I have been playing with cars since I was 11 (now 38), and can tell you for sure these guys won't steer you in the wrong direction.
Now, answer my question above.
Now think about this very hard. YOU CAN DO ANYTHING ON YOUR CAR YOU WISH TO. You do not have to pay money for the simple stuff to be done......ever! You can crack open the motor, and you can do the work (I'd leave the porting stuff to experienced help, and research who you plan to use before you send the first dollar, or part to them for work.)
Now, you need information that would take too long to give you in a forum. First, you need a book on basic engine tuning (old school carbed engines are simple to work on and simple to troubleshoot.) If you can learn from that perspective then the newer EFI engines will be easier to understand.
Most good auto parts places have a book section in them. Go get a book on your car (specific year models in the list of coverage), and read it from cover to cover to familiarize yourself with what is where and what it does. You can also find books in this section on building high performance Ford engines. Pick one up, and read. Go to Amazon.com and locate some books that will help along the way. Read like mad.
The single best tool you can have is knowledge of what you are looking at, and what you wish to do. These guys can help.....AND WILL.
Thanks Doc. That's just what I intend to do. I've also talked with a couple sport tuning places that specialize in late model mustangs and they've indicated a willingness for me to come by and get an orientation as well. That will also get me familiar with who's out there to do the stuff best left to the experts.
Need an "Enging 101" Lesson 
Tech 
