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A beginner's guide to modifying your V6

148K views 188 replies 71 participants last post by  crjackson 
#1 · (Edited by Moderator)
So as i flip through these pages day in and day out, i feel we find a lot of the same threads:
"which intake is the best?"
"What gears should i get"
"What exhaust should i get"

And i just felt it may be beneficial to have a "sticky," or "beginners guide to understand your v6," so to speak. This is not a be all, end all tuning guide, it is simply meant to be a starting point.

Eventually this post will be updated with links and datalogs, and charts, and graphs as we all work to compile useful data, but for now i'm just going to get down to the nitty gritty. Please, feel free to discuss anything you would like added to the OP, and i will do my best to make this a user friendly and understandable guide.

For starters, The forum is here to serve as a knowledge base for those interested in learning more about their cars. Since this platform has been out for nearly 5 years now, there is a good chance most basic questions have already been covered, and one can access that information fairly easily in a few easy steps.
Simply type your question into google: " Mustang 3.7 Air raid intake..." Followed by the forum you wish to search: "Mustang 3.7 Air raid intake mustangevolution" and Google will pull all the threads on that forum with those hot words in the title. You may have to get creative with your wording (remember, less is more so you can pull in a wide variety of threads), but all of the information and more is easily accessible this way.
The goal here is to avoid 100 threads on the exact same topic, and the useful information that may be in 1 or 2 of those threads getting buried and lost. Hopefully this helps those eager to learn, but for now, lets discuss what items you can search to further your understanding.

1. The Cold Air Intake.
Ford has actually done a pretty decent job with the factory intake, so for most practical purposes your aftermarket CAI will serve two purposes: Sound, and bling. This will be true on about 75% of the cars out there, but there will be cases where more airflow will allow more power.
The reason the aftermarket "No Tune Required" intakes do not require a tune, is because the MAF (Mass Air Flow) sensor diameter is the same as stock. The MAF calculates how much air is being brought into the engine and adds fuel accordingly. NOTE: if you do change to an air intake with a larger MAF diameter, YOU MUST have your car tuned for it or you will run dangerously lean, no if's, ands or buts about it.
So, the argument here is that an intake that is larger than stock will have a higher flow potential, and could possibly bring in more air than an otherwise stock sized intake could.

2. Throttle Bodies
There has been a lot of discussion on Throttle Bodies, and i'll admit the information seems very garbled. Some say it makes a massive difference down low, but virtually no peak gains, some say it is hands down the best money they have ever spent ... I personally believe this forum could benefit from understanding the value of datalogging. A datalog can very easily show where areas in the RPM band are flowing more air / less air / the same air... all those factors will determine power. This is a section i will come back to later, as i hope those here who have first hand experience can allow me to elaborate.

3. Headers.
The general consensus here (as well as in the 5.0 forums, where i spend most of my time) is that Long tubes will net you higher peak gains, and shorties will give more low end and mid range grunt.

Longtubes: Long tubes will require a tune. One, because you are deleting the cats, but two, because of the way headers flow. The technology in these Ti-vct motors is incredible, and they basically allow you to tune the car to optimize virtually any set up at any rpm. Here is an article on understanding tuned length headers, and how the Ti-vct system allows us to maximize these gas pulses, but also why the tune is incredibly important to making power.
Let's get technical. The biggest controversy in header design is the "equal length" versus "shorty" styles - which is best?

As far as the rest of your exhaust, you will need a mid pipe that is designed especially for long tubes. This is very important when planning your exhaust mods, a mid pipe that works with stock headers WILL NOT work with long tubes.

Shorties: Whether a tune is "needed" with shorties or not is another highly debated topic. Seeing as how the runners lengths are still "tuned," i believe the cam timing can be optimized to match, therefore i would suggest a tune. However, the changes are a little less drastic than longtubes, so you likely can get by without a tune for some time.

4. Midpipes: The Factory mid pipe is a Hybrid H/X pipe with 2 cats, and 2 resonators. Your aftermarket mid pipes will come in 1 of 2 configurations, either a dedicated X or H, with the option of cats or no cats typically.

X-pipe: It has been dyno tested that an X will make more power, however marginal it may be (typically 3-5 whp at best). Typically however, your X-pipe will induce a LOT more rasp, something someone may want to keep in mind when choosing their mods.

H-pipe: Again, as was said above the H-pipe will give up a few whp to the X-pipes, but the lack of rasp may be a little more what some folks are looking for.

Cats Vs Catless: Depending on how strict inspections are in your area, you may want to choose an aftermarket mid pipe option that includes High flow cats. High flow cats are an interesting topic, and one that is also highly debated, but i will include my personal opinion. The only reason cats are "high-flow" is because of the number of cells they have, the fewer the cells, the "higher flowing" it is. Well, if a cat flows enough, it can still register (as far as the computer is concerned) as "catless" and cause issues with emissions testing. Just food for thought. Personally, i would either go catless or stick with the factory pipe. I personally dont see the point in spending $500+ on a mid pipe that still has cats, but this is a decision you will have to make for yourself.


Gears: Gears will basically change how your car reacts in its powerband. A longer gear (smaller number) will mean longer gears or more time in gear, whereas a shorter gear (higher numbers) will move through a gear much more quickly. There is a balance, people get hung up on the fact that the car is "revving faster" with a higher gear (4.10 ...) but that does not mean the car is going faster. A higher gear will mean more acceleration, but there is a point of diminishing returns as far as overall acceleration and speed is concerned.

Your typical "all around best gears" are going to be anything in the 3s, 3.31 - 3.55 - 3.73, and your more extreme, really 1/4 centered gears will be anything in the 4s, 4.10 - 4.56 ...
This changes the more power you have however, a 3.73 may be a very well rounded gear for a lightly modified car, but a boosted 3.7 making 400-450 whp will certainly want a longer gear, something more along the lines of a 3.31 or 3.55. The more power you have, the less gear you really need (or in fact, want) because you want to let your car pull through the more powerful powerband.
The factory gear is a 2.73, which is a LONG gear designed for one purpose: gas mileage, and this brings us to our next point. As you move to a gear designed more for acceleration, it means you will impact your gas mileage as well. Typically a gear that is more acceleration oriented will actually improve city mileage (if you can keep your foot out of it) while decreasing hwy mileage. There is a LOT of information on this forum regarding gears, this thread is not the place to discuss that. A good way to easily find information is using the "google search" technique. Simply type your question and forum name into google: "3.7 mustang best auto gear mustangevolution," or "2011 v6 mustang auto 3.55 mustangevolution," and it will pull up threads on this forum. You may have to experiment with your wording, but the information is out there, and it is plentiful.

Tuners: The tuner is likely going to be the best bang for your buck on your modern engine, allowing your car to optimize either its factory components or aftermarket parts you have added.
A tune consists of a handheld device that you can load tunes on, that can then be loaded onto the vehicle. This handheld is also your means of datalogging your car, for either your own understanding or for sending logs to your tuner for reviewing. NOTE* virtually all hand held devices, save for the very newest models, will require a laptop for datalogging. It is important you have a firm understanding of the software, and the PIDS your tuner wants logged for a successful tuning experience.

What a tune does: In a nutshell, the tune is the recipe for success. Think of your car as a cake so to speak... you can have the best parts (ingredients), but if you have a poor recipe, you will have a poor cake... The tune basically adjusts (or can adjust) every single performance aspect of the car so that everything works in harmony for the best combination of performance, driveability, mpg.

Air / Fuel ratio: This is very straight forward, the ratio of air / fuel that your engine is burning. For those that have a basic understanding of chemistry, the basic Stoich ratio of gasoline and air is about 14.7:1, and this will be your ideal "cruising AFR." As you transition into WOT conditions, it is very common for your tuner to richen up the mixture; 1, for safety (making sure the engine does not run lean), and 2 too cool things down. The reason lean conditions damage a motor is because lean is VERY hot and will melt or damage critical engine components. Most tuners in the Mustang community chose to measure AFR in lambda, which is typically given as a ratio of 14.7, with 14.7 being 1. Numbers 1 will be leaner.

Spark advance: This is the amount of advance before TDC (piston top dead center) that the spark plug will fire and ignite the air / fuel mixture. If the spark plug fired right as the piston reached the top of the cylinder, the piston would already be moving back down as the flame expanded, and you would end up with a very weak powerstroke. By advancing the spark, you can basically time the explosion of the Air/Fuel mixture to do the most work on the piston, and make the most power. This is a very critical part to making power, but is also one of the easiest ways to damage an engine. It is not uncommon for a novice tuner to get carried away with their new found power and actually advance the timing past MBT (Maximum Brake Torque) and actually have the piston advancing up into an already lit Air / Fuel mix which can result in bent rods.
---Knock ******: Knock ****** is the amount of spark advance being removed from the engine if the computer detects a "knock event." A knock event is when the air/fuel mix ignites before the spark plug actually fires. This can be very dangerous and lead to damaged pistons, or bent rods (similar to passing MBT as i mentioned above), so the computer will remove spark advance to subdue this. Spark advance makes power because it increases cylinder pressure, Heat + Pressure will lead to more power, but also the potential for knock, therefore reducing the spark advance will reduce the pressure and the chance of knock.

Cam Timing: Each component of tuning is enough to have its own thread, if not more, especially cam timing. The important thing to know is that each mod that effects airflow can be optimized through cam timing. Power is made in 1 of two ways: Air speed velocity, and maximum CFM (cubic feet per minute) flow.
Air speed velocity: Torque is directly dependent on airspeed velocity (both intake and exhaust), the faster the air moves into and out of the engine, the more torque you will have. This is especially true on the exhaust side (remember, tuned headers...) and leads to the common misconception that "back pressure means more torque," which it does not. A smaller exhaust pipe means higher air speed, at the cost of overall flow, which is why on cars not equipped with technologies similar to the Ti -vct you would tend to lose torque going with an aftermarket header.

Maximum CFM: Obviously this one is straight forward, the more air you have, the more power you can make. Keep in mind when choosing your mods however, the flow and velocity have to work in a balance. Tuning the cams can aid to some extent, but typically more of one means less of the other. This is why its common to see a low end torque trade off for high rpm horsepower (think Boss / CJ manifolds).

Shifters (auto only): The tune can adjust shift firmness, the time of the shift, and basically every function of an automatic transmission. Faster, firmer shifts can lead to faster times at the track, but can also be a lot to live with on a day to day basis. Also, on the 13-14 models, the tuners do not have the ability to adjust the way the car shifts in sport mode. Your car will still be tuned when driving in sport mode, but the shifts will be the ford factory "sport shift" settings.

Feel free to link my thread on bama tunes and anything else to the tunes if you would like. Reading through that thread will answer pretty much any question someone wanting to tune will have . Good job again on this

Sent from my 831C using Mustang Evolution mobile app
http://www.mustangevolution.com/forum/f356/t356228/




Suspension:

Lower control arms (and brackets): I believe there is a lot of debate regarding lower control arms and brackets. If your car is lowered... at all... regardless of how small of a drop, you need lower control arm brackets to correct the suspension geometry. People say their car gets by fine, and drives fine, and you dont "need" them, but i disagree 100%. The car WILL NOT load the rear axle properly without relocation brackets (if the car has been lowered), and the car will suffer during launches and shifts.
Upgraded lower control arms come in a few variations, poly bushing vs spherical, fixed vs adjustable... i will leave you do do your own research in regards to those, but i will just cover their general purpose: which is to put load on the axle.
Your lower control arms are anchored on one end on the body, and at the other end on the axle. When you accelerate and the car shifts weight to the rear, it transferees the weight onto the rear axle and improves traction. The stock LCAs have a very soft rubber that tends to deflect during hard driving, and upgraded LCAs will improve the weight transfer.

Upper control arm (and bracket): This part is critical for correcting pinion angle. This is important when a car is both A. Lowered, and B. has a one piece driveshaft. It is very commonly known that an aftermarket UCA will cause a "clunking" noise when used with the stock bracket, so it is highly recommended to upgrade both at the same time.

Adjustable Panhard Bar: This is another critical piece to upgrade when the car has been lowered. One end of the PHB is anchored on the body, and the other on the axle. When the car is lowered, it will cause the body to shift in relation to the axle, so it is very important to have an adjustable panhard bar to re-center the body over the axle.

Sway bars: I believe there is a lot of confusion understanding the point of a sway bar, it is not simply to "reduce body roll." The point of a sway bar is to adjust grip independently between the front and rear, depending on whether your car is "pushing" or "pulling" in corners. This is a part 90% of street cars will not need, but is not something i will not spend the time explaining, i'll allow this article to. This is just another one of those mods you will need to do research for your specific goals and needs.
Car Suspension Tuning: geometry setting guide

Strut bars: Again, another part that is supposed to reduce body roll. There are some that will work really well, and some that i believe are all fluff ... this thread is not really meant to be the time or place for that, just another mod you will have to research for your goals and needs.

Brakes: Big brake kits do not mean more stopping power. Again, big brake kits DO NOT mean more stopping power. The point of a "Big Brake Kit" is for higher heat retention, and a fixed caliper + more pistons for more even pad wear on a road course. All a street car, or even mild track car, needs is a decent set of pads and rotors. For example, i run a set of Carbotech XP10 (more of a track pad, not really recommended for street use), and just a set of centric premium rotors on my GT (non brembo) and i can kick the abs on at about 75% braking with 295 nitto NT05s on all 4 corners. What this means is i still have WAY more brakes than i do tire. If you want better stopping power, what you need is good tires. Tires + a good set of pads + a good set of rotors, in that order, is the recipe for better stopping.

Drilled and/or slotted rotors. These are a gimmick, they look damn cool, but will offer 0 performance benefit over a premium blank rotor. Drilled rotors crack, period, it is not a matter of If, but when. Drilled rotors means less thermal mass to absorb heat, and less surface area for the pad to provide clamping force, they are a waste of money, and not beneficial in any way other than cosmetics. Slotted rotors are somewhat the same, really you're just paying for looks, and they do look cool, but just keep that in mind when shopping for brakes.

Cross-Drilled Rotors Myth - Xtreme Import Performance


I think that basically is "modding 101" for this car, and if anyone has any items they would like added to this list, i will do my best to implement them. There will likely be some disagreements, and i have tried to keep this as objective as possible, but again i am not claiming this to be the end all - be all of modding, just simply a good starting point. I welcome any and all feedback, and hope we can make a solid beginning guide for people looking to modify their 3.7L mustangs. Eventually i would love to have dyno graphs, datalogs, and other hard data for people to be able to look at and decide how to start modding their car.

Here's a compilation of 3.7 V6 exhaust videos http://v6mustangperformance.com/productreviews/3-7l-v6-mustang-exhaust-clip-compilation/
 
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#3 ·
Good info voltwings! ?

Sent from my SM-N9005 using Mustang Evolution mobile app
 
#7 ·
To keep these thread on topic, i dont really think we should dive into which particular mod is the "best," this is really designed to be more broad and just cover what each modification does more or less.

I'm sure there are other posts on this forum that are more geared towards your specific question though.
 
#12 ·
+1
 
#23 ·
I doubt anything will reduce those threads...
 
#11 ·
Very nice write-up. Thank you very much for sharing.

It'd be helpful to add a paragraph on axle-backs.
 
#26 ·
Feel free to link my thread on bama tunes and anything else to the tunes if you would like. Reading through that thread will answer pretty much any question someone wanting to tune will have . Good job again on this

Sent from my 831C using Mustang Evolution mobile app
 
#29 ·
#30 ·
Awesome write up, should help a lot! I know it helped me understand things a little better.

How about making it manditory for all new members to visit this thread before posting?

Also here is a great link for exhaust clips for the 3.7:
3.7L V6 Mustang Exhaust Clip Compilation | A 3.7L V6 Mustang Owner Resource for Modifications and Repairs

Thanks for the link, i am trying to move this to the OP, but it looks like the "edit" button is gone ... is there a limit to the number of times you can edit a post?
 
#31 ·
An addition to the exhaust section comes to mind. Obviously sound is very subjective, but the topic of power gains and back pressure have been beaten to death, axle backs vs cat backs, pipe diameters, etc.

Maybe even how to change the sound with things like resonators. I'm in that boat personally, finding the perfect placement for resonators to eliminate the new drone and the ever present rasp.

Sent from my SM-G900V using Mustang Evolution mobile app
 
#32 ·
That!! And the issue of hi flow cats. I personally haven't heard em in person, however they're known to make your exhaust system loud. Do they bring in rasp/tin can sound like a catless system? And by loud, does it mean they will amplify the 'mild' gurgle of stock/gt500 exhaust?

Just a couple of questions I have, much like a noobie going to venture into this setup.

|| ~BlackOnBlack~ ||
 
#34 ·
Good write up.

Could it be expanded to break it down to a bit more detail on each section? For example tuners, maybe a breakdown of the more popular brands of tuners, what they do and where to find more detailed info for each brand. Or exhaust, again the most popular brands, straight through vs chambered, build material etc. all while trying to keep opinions on what's best to a minimum.

You could almost have a separate sticky for all the major common areas of mod - tuners, suspension, exhaust, intakes, FI. That could really help IMO.
 
#36 ·
I have lost the ability to edit OP it seems (must have been edited too many times already) but at some point i can look to sit down and make something like this. I really do appreciate others input on this, its not something i want to take all the credit for (nor certainly be solely responsible for) so i appreciate any and all input.
 
#66 · (Edited)
HOLY ****ING **** YES!! Im so tired of seeing the same threads on here over and over "Im buying headers soon, should i get LT or Shorties? :lalayla:" (add a ****ing hello kitty gif in there as well) :facepalm:
Somebody with REAL power on this site...Voltwings, SoCalStang, ANYBODY?! Can we make it a requirement that new members HAVE to read this before joining into threads or Starting their own threads. Its such a waste of space that you cant find articles anymore in the search because EVERY thread has some post by an idiot about something that was covered extensively on another. try searching for grabber thread...i bet you it will be close to the bottom because its been pushed (no cheating by searching his SN either).

Also I push to ban or immediately close all threads started with some reference to "V6 vs V8"....its ****ing annoying...grow up.:banghead:

OP!...Here it is...3rd from bottom! http://www.mustangevolution.com/forum/search.php?searchid=3926617
 
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