redbar0n11

I just recently bought my '07 GT and I have some questions and observations that maybe someone can shed some light on. First off, it's a 5-speed and I notice that in 1st and 2nd gear, it's really sluggish until you hit about 2k RPMs and then the power kicks in. Is this normal with the stock gears or something? I know that a lot of people upgrade to the 4.10's to get power in 5th gear, but never heard anything about 1st or 2nd. I do not have the Interior Upgrade, but I was wondering if anyone knew if it was possible to upgrade the guage cluster to the optional one with the information center and the my colors option in it? Is it a straight swap, or would it be more involved? I am also looking to Mod a lot more of the car especially the stereo. I have the Shaker 500...want to put in double-din 7" touchscreen HU. Will the stock speakers/wire setup be compatible? Or does aftermarket stuff not jive with the factory components? I want better speakers, just might not get them at the same time as HU - if you know what I mean. And finally for now, what's the best bang for the bucks when it comes to semi-minor performance upgrades? Pulleys? CAI? Mass Air? Throttle body? Exhaust? Headers? Anyway, thanks for reading. SORRY POST WAS SO LONG![sm=sleeping.gif] I appreciate the input. I'll take all that I can get! Thanks all!

rmr1923

as far as all the interior stuff goes, i have no clue because i don't pay much attention to how my car looks, mostly how it runs. the first thing you should probably do is change your gears to a 3.73 or 4.10. if you drive on the highway a lot and are concerned about fuel mileage, then try a 3.55 maybe, or don't mess with them at all. but from the factory, the Mustang has a VERY conservative gear that's aimed (it would seem) at getting a respectable EPA fuel efficiency rating. the gears themselves aren't too much, you can get a good set from Ford Racing Performance Parts for under $200, and you're looking at anywhere from $250-$400 to have them installed. you'll also need a speed corrector, otherwise your speedometer and odometer will be off. i'd recommend getting some sort of flash tuner, like a Diablo Predator or something like that. you can program what size gear you get with that tuner, as well as getting some more go from your engine with the more aggressive tune. you can get a good tuner for about $400-$500 probably. JMS has their own custom tunes, and i loved the custom tune they did for my car. i got a custom-tuned X-Calibrator for $380 and it was a noticeable difference. the amount of modifications you do really depends on your budget. another thing you should probably do is a cold-air induction. for about $200, you'll boost power a little bit, get better fuel economy since the engine breathes easier, and the filter only needs to be cleaned, never replaced (unless it gets torn for some reason). you may also consider a bigger throttle body and MAF meter to increase intake flow. on the exhaust side, you should probably do a cat-back exhaust system. i'm not familiar with the systems for the newer 'Stangs (mine is an '02), but you should be able to get some good advice from other guys on here about exhaust systems. i'd recommend replacing the entire exhaust system, from the headers on back, but it can get really expensive, so a cat-back exhaust is a good starting point, and you can always get an x-pipe and headers later. whenever you do mods like this, you may want to have your tuner re-programmed to get the most out of them. whoever you order your tuner from, make sure you can send it back to them for a re-program any time you make changes. if you're looking to do a little bit more work, a set of cams will really open that motor up. i'm not sure about the new 3V engines, but my '02 2V engine has a horrible top end. it pulls great until about 4000 rpm then just sort of dies, it's really pathetic. i just ordered a set of Comp Cams for it (about $700), so that should open my top end up a bit. you may also consider a supercharger. go pick up any of the Mustang monthly magazines and there are articles everywhere that deal with 3V supercharger installs, and the power increases are amazing. in my opinion, a supercharger is the best power-per-dollar modification you can do, but then again it just depends on your budget. a good supercharger kit will run anywhere from $3500-$5000. i believe JMS sellsa kit that includes the fuel injectors and a custom-tuned X-Calibrator 2 tuner as well. what modifications you do also depends on your level of expertise. if you have limited mechanical knowlege, you should be able to install a cold-air kit and throttle body with no problem. a supercharger may be a little complicated if you're not familiar with general engine function and repair. you'd hate to get in the middle of it and not know where everything bolts back up to. this post got a bit longer than expected, but i hope it helps.

redbar0n11

Do you or anyone know what the ratio of the '07 gears are stock? Just to compare how big of a change it is to go to the 3.55, 3.73, or 4.10's... I guess I do a good deal of "highway" to/from work daily. It's not that far, but it's 55+ mph driving. Now, correct me if I'm wrong, but tuners change things like air/fuel ratios to get you more power, but at the cost of fuel efficiency? B/c I was looking into getting the Stage 1 Ford Racing package that came with a tuner that changed it to a 93 octane. I know thatI will get a CAI, just don't know which yet, but ifI got the FR package, it came with the K&N. I also want the twin 62mm throttle body. Now I figure if I retune the engine or install better gears, that by getting a CAI, throttle body,and even the MAF (even exhaust too)... that all of those could replace the fuel efficiency that was lost by the tune and gears... I am definately interested in doing intake/exhaust work... but that will probably come later. As for things like superchargers or cams, I think I wanna stay away from those fora little while. I only have 7k miles on my 07'...I think I wanna keep my warranty a little bit longer . Anyway, thanks for the post. Anything is appreciated. I was kinda shocked to see such a long response (not a bad thing), butI was definately not disappointed. Thanks again.

rmr1923

i'm not too certain what gear it comes with from the factory. i believe my '02 comes with a 3.27 rear gear (or something close to that). here are a couple formulas that will help you with gear selection, but first off, let me define what the variables are:

FD- Final Drive, to get this number, simply multiply your rear-end ratio by your transmission gear ratio
RO - Rollout (this is a circle track term).. take the diameter of your tire and multiply by 3.14, or get a cloth tape measure and measure the entire circumference of your tire

If you know what speed you're going to be cruising at, you can calculate the RPM with this forumla:
RPM = (MPH x FD x 1056) divided by RO

This is handy if you know your current gear and want to see how much higher RPM you will be turning with a gear change at that same speed. Of course you'll need to know your transmission ratios, rear end ratio,and tire circumference (or rollout). Here's another way to find your tire diameter if you don't have a tape measure. Let's say you have 245/45R17 tires on your car (i believe this is the size tire my car came with in '02, although i'm running 275/40R17s now). So take the 245 and multiply by .45, this will give you the size of the sidewall, and then you'll multiply this by 2. So for a 245/45R17, this number will be (245 x .45 x 2) = 220.5mm. Now take that number and divide by 25.4 to get the height in inches. So 220.5/25.4= 8.681 in. Add this to your 17" rim diameter, and the diameter of your tire is 25.6811 inches. So for this 25.6811" tire, the rollout is 25.6811 x 3.14 = 80.6796 inches, so you'd use 80.6796 as RO in your RPM calculation. i might just put this all in a spreadsheet, i've been considering a gear change lately so i'd get some use from it too. if you'd like the spreadsheet, PM me your email address and i'll send it to you.

redbar0n11

Wow... You sure have done your homework. This is exactly what I have been looking for. I will definately PM you my email. A spreadsheet would be neat to play with. I work for a software company so that's right up my alley . Now, pardon my ignorance and confusion, but the gears that we have been talking about (i.e. the 3.73 or 4.10's)... what are these gear for? You mentioned rear-end ratio, and I'm doubting myself as to what gears these are for... transmission? (rear-end ratio made me think of differential...?) haha, wow... you can tell I'm a noobie when it comes to engine/powertrain parts still. I'M LEARNING THOUGH! [sm=icon_cheers.gif]Thanks a lot for all this and your time/interest to help a rookie!

birdoffire7

3.55 is stock.

rmr1923

when i talk about 3.73 and 4.10 gears, those are the rear-end gears, and yes they are housed in the differential housing. the "differential" is what the gear physically bolts to, and which allows the rear wheels to spin at different speeds when you're making sharp turns (otherwise one tire would be dragging and your car would be hard to turn). the only way to change your transmission gear ratios is to swap trannies, but i doubt you'd have any need for that because the gear ratios are pretty good on the stock Mustangs.

i sent you that spreadsheet. it's nothing fancy, but it should help you out with what you need. i also included a MPH calculator if you plan on taking it to the strip. it may or may not be of any practical use, but i was bored so i did it anyway. if your stock gears are 3.55, then swapping to 3.73s would probably be a waste of time and money, but 4.10s may give a noticeable boost in acceleration (at the cost of gas mileage on the highway though). if your car currently has 3.55s, then you'd be better off spending your money on the intake, exhaust, and tuner first, along with the interior upgrades you're considering.

redbar0n11

Ok, cool. Good to know. Now I know that birdoffire7 said that stock was 3.55, but I found this in an online brochure from ford on the mustang:

Includes V6 Deluxe content, plus:

manual GT transmission (3.31 axle ratio) • Stainless steel dual exhaust with

bright tips • Power 4-wheel disc anti-lock brakes • Front and rear stabilizer

bars • Traction Control • Fog lamps • Rear spoiler • 6-way power driver’s

seat with power lumbar • 17" painted-aluminum wheels • P235/55ZR17

performance tires

Is the axel ratio what we're talking about here? Cuz if so, that says stock is 3.31. Still dont know what the tranny ratio is, still looking. Thanks guys!

rmr1923

axle ratio will be the rear end ratio. i tried to do a search to find your transmission gear ratios and didn't come up with anything. you might call the service or parts department of a Ford dealership in your area and ask if they can tell you what rear end gear ratio comes in your car, and ask if they know what the transmission ratios are for each gear in your tranny. my guess is that your 5th gear ratio is probably between .65 and .70. I believe the one in my '02 GT is 0.67 for 5th gear, and the rear end came stock with 3.27 gears, so a 3.31 axle ratio for your car sounds about right. i'd still call a service department and ask if they know, and if not, ask if they know who will.

redbar0n11

I found a great source for all the info I needed. It broke down all the ratios...everything.... I mean just about everything for the car. Turns out my ratios are 0.72 & 3.31 stock.

Here's the link: http://www.conceptcarz.com/vehicle/d...ptionalEngines

The V8 Optional engine stats are at the bottom... I might post this link and the spreadsheet for others to use in a new thread. Seemsa lot of people have questions just like what we have been discussing. And the spreadsheet & linkcould solve a lot of questions... We'll see... I'll embed a picture of whatI came up with for my car (in case anyone out there with a manual 2007 Mustangis reading this). For clarity, all of these figures represent conditions IN 5TH GEAR using 235/45R17's. The Gain column = RPM increase from stock gears (3.31). ThisSHOULDbea good estimatefor any 2007 Mustang 5-speed using similar wheels and tires, mine happens to be a GT (but transmission ratios appear to be the same for all 2007 5-speeds) *DONT QUOTE ME ON THIS* I guaged this info from the link above! Peace out!

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