Alright, I know this will be a totally noob question/post, but work with me here..

I am looking to get into a 99-04 GT by the end of the summer, and I am working my *** off to do so.

So, obviously, I came to mustangboards/mustangtuning. Here are my questions (and these could apply to all automobiles) - keep in mind, I love cars, know a decent amount about them, but I dont work on them or anything so I dont know certain bolt ons/mods.

What do gears do for you? 3.73, 4.10, etc? What are they?

What do underdrive pulleys do/what are they?

And one I feel totally stupid for asking, what exactly is a catalytic converter, what does it mean, is it better to go catted or catless, difference between them, etc.

This post is probably way under you guys, so dont feel like you have to answer any of my questions, but if you do, I appreciate it alot.

 

you shouldnt feel stupid at all...once i had these questions

the gears will help you accelerate faster but decrease your top speed...i think most 99-04 GT's come with 3.27 gears and if you went to 4.10 you would really feel a big difference in acceleration

underdrive pullies i am not really sure...just pullies that go on the belt on the engine...someone else can answer that

and cats...basically it keeps harmful things from coming out of your exhaust and keeps your car street legal (in some states that matters). Depending on what state you live in, you can decide if your state checks for emissions...kansas does not. but alot of states look for that and therefore you would want to go with a catted midpipe...if the state doesnt care or does not inspect your vehicle for that then get off road (or uncatted) midpipe

well im not much of an expert but i hope that helped a little

 

Yeah it did alot actually. Thanks alot for the response, I'm hoping to get into a GT and get some SLP exhaust, gears, and pulleys before christmas. I am very anxious haha.

So I have a much better understanding of gears, but what exactly are they?

 

http://www.mustangtuning.com/rearend...FT2GFQodExG81A

they sell them at mustang tuning...they allow the rear end to rotate at a faster rate...therefore increasing acceleration

but i am no expert...someone will chime in soon who knows more than me

and for the exhaust i would recommend if you want the full slp setup to get slp long tube headers, slp catted or uncatted x hipe, and the loudmouth 2 catback...the loudmouth ones are really really really loud and raspy when you have no cats

 

The number of the gear (3.27, 4.10, etc.) is actually a ratio, for example 4.10:1. The ratio is the number of times the driveshaft rotates for a single turn of the wheels. The higher the ratio, the more engine torque is multiplied, thus making your car accelerate more quickly while sacrificing top speed. I highly recommend a gear change (at least a 3.90).

Underdrive pullies are replacement crank (smaller), water pump and alternator (larger) pullies. The idea is actually similar to that of the gears, by changing the ratio of diameters of the drive and driven pullies, you are sacrificing the speed of rotation for the ease of rotation, effectively using less of the engine's power to turn the accessories. I don't recommend going with pullies, IMO they aren't worth the money.

Catalytic converters are chambers that are inline with your exhaust which convert harmful emissions into less harmful emissions by passing the gasses through a "filter" that is coated with certain catalysts. While that is great for the environment, the 4 that your mustang comes with stock rob about 20RWHP from you. When you get a new midpipe, go with a catted one (not only does it have 2 less than the stock mid pipe, the 2 remaining are much higher-flow than the stock 4) or if you must go with off road (catless).

Hope this helps.

 

lol see i had some of that...just shorter version

 

Awesome guys, thanks a lot for the responses. I feel much more...enlightened now. It helped alot.

 

Now tell me, why do manufacturer specifications say 260hp with 302 lb of torque, but some cars only dyno at like 240 with bolt-ons? =( i dont get that.:foot:

 

I've seen that as well. I think that is referring to rwhp (hp to the wheels) - the specs saying 260 hp stock are saying to the crankshaft, which is always higher than the hp to the wheels. I think the 260hp engine puts out 215 or so hp to the wheels. It's always around 35-65 hp lower than crank hp, I believe.

Another question, sorry guys. When you get a "tune," what exactly does that consist of? Are there new parts involved, or is it basically a tune-up, where everything is refreshed and what not..?

 

interesting, what is at the crank mean, (big noob = me)

 

lol @ this thread!

 

Why do you have to be mean?

 

Well, horespower specs from the producer, mustang GT being Ford, are measured in hp put out by the engine unit (at the crank), being 260 hp. When you dyno your car, power is measured in horsepower at the wheels, mustang being rear wheel drivetrain, it is rwhp (rear wheel hp) - the difference, im not quite sure. Rwhp is the hp that is actually getting to the tires, while crank hp is what the engine/motor is producing possibly when not being applied to the wheels? That is what I have come to speculate, someone correct me.. haha.

 

Your right. A 99-2004 mustang has 260 HP to the crank, what the engine itself(crankshaft) will actually dyno but it will put aournd 220 HP to the wheels, and that's due to drivetrain loss like transmission, driveshaft, rearend, then finally to the wheels. usually manual transmissions lose 12-15 % and auto 18-20% drivetrain loss. Autos lose more cause they are bigger thus having more internal gears and such that do alot of work.

A tune can be done via programmer like diablo predator or also by a custom chip, i prefer the chip, they can play with alot more areas in the computer.
A tune-up is your basic spark plugs, spark plug wires, sometimes people do little extras here and there when it's time for a tune up. like me, i'll go ahead and flush the radiator, new pvc and so on.

I've always felt a difference with pulleys and have had them on my 95 GT and my 97 Saleen. I've seen them get 3-5 HP and same TQ on the bottom end but around 10HP on the top end, and that's on a dyno before and after dyno. Also if you take your stock crank pulley off and hold it and the new under drive pulley, you will definitley see a size and weight difference and that's what takes the parasitic drag away. Then of course the alt and water pump has to be a little bigger to accomendate for the crank pulley becoming smaller and being able to use your stock belt, in most cases.

I would def. go with gears first as being your first mod, either 3.73's or 4.10's. It multiplies the torque, as mentioned, and you will think you gained power, though the wheels are now turning at a fast rate. It will also help your city mpg, with gears, it takes less strain off the engine to get your car to go from a red light, thus less gas to make it go. but if you beat on it from redlight to redlight, then the mpg's go down. Hwy might go down and maybe not. Your top end wont be affected to much. my 95 GT had 4.10
s and it could do 145mph, my saleen has 3.73's and i'v gotten it to 130mph

 

Dont feel bad being a noob, we all started there once too, just be prepared because sometimes noob questions are entertaining - lol

I won't try to answer things that have already been covered, but let me help you understand gears better....

Going from stock gears (3.27) to 4.10's, is like driving a 10 speed bike and changing the sproket in the back so it is easier to pedal. You can now accelerate better, but you loose some top speed.

IMO keep your cats. Why?

1 - High-flow cats work nearly as well as going catless

2 - Removing the cats require other tricks like turning off the o2 sensors etc... it is not hard, just added steps.

3 - It is environmentally sound....sorry, I am no tree hugger, but no sense in adding to polution.

4 - Keeping your cats will give you some great exhaust options and the car can still sound amazing with them.

 

lol @ me for being mean!

 

Awesome, thanks guys. Now I have another stupid question, Im sorry! The more I read these the more I wonder.. but yeah this thread will die soon no worries.

When purchasing exhaust, gears, etc., when i purchase those, since they are pretty much direct bolt ons, do i purchase the exhaust setup and gears and thats all i need for installation and everything? Or do I need to purchase components such as x pipe and y pipe for the exhaust, or are those not necessary? Sorry guys... Thankyou for all the explanations..

 

for the exhaust...if you want a catback system only then you do not need a new midpipe...and u need no special tools besides some sort of saw that will cut the old system out...

as for the gears you should get those installed profesionally at a speed shop or somethin...

 

ah, interesting! thank you for the explanation! :banana:

 

gears are a great first mod. However with the 99+ cars you'll need some way of correcting the speedo. hence why alot of people get a tune / programmer. that or a speedcal.
UD pullies I have them IMO if I hadn't gotten a steal of a deal I won't have them. Ac doesn't blow as cold and didn't make much difference on my car.
Exhaust Ok depends on your state. Also there are some federal laws dealing with cat's. It is the main reason why I went with shortie headers. I can always slap the stock h pipe back on if I need too. But in the exhaust you'll see your biggest gains in a OR mid pipe and headers. a catback IMO is just for the sound/ appearance.
Tune - most are referring to having the computer tuned. The best is on a chassis dyno preferable a loaded one, with a good wideband o2. The tuner's that are good will work to insure that the car is safe and making good power through out the rpm band. Now as far as handheld vs chip. I have a handheld and kinda wish I had went with a flip chip setup now.

 

Pulleys won't interfere with your AC, it must need recharging.

 

I wouldn't attempt to install gears yourself unless you really know what you're doing. Also, you're looking at around $400-500 for a gear mod after all is said and done. Maybe more if you're doing a full tune to fix the speedo.

 

ok for your question about gears the magazine "modified mustangs" the june 2006 issue has an artical that would help you a bunch. the article is called "dont fear the gear" it tells you all you need to know about what they do and the pro's and con's to each ratio.

 

I've got a question... your getting gears and your car is your main auotmobile... what is more I dunno cost worthy I guess? You want that quicker acceleration but then again your drivin it everyday... 373 gears or 410 or anything else maybe

 

My 95 was my daily drive and it had 4.10's in it but with the saleen, i drive it when i can and it has 3.73's. it's good to go if i drive it to work or if i'm driving it hours away. Gears is the best bang for the buck and if you can afford to buy them and have someone install them, then that would be my first mod.

For the Tuning part, if your close to NC, i recommend pro-dyno. Just make sure you call a few days before you appointment so they know you are still coming. but they know their sh*t.

 

Anybody know any good places out in Cali....I'm around the Sacromento and San Fran area....Fairfield(Travis AFB)

 

Ok being a first time bolt-on modder like yourself, you prob. wont be able to install the gears or the pullies. The cat-back and mid-pipe are a lot easier only wrenches, extensions, and perhaps a swivel which will allow you to get to those hard to reach bolts. You'll need an air gun or impact wrench to get the pullies off and the gears you'll need the correct spacing and install can be tricky. Go with cold-air intake and exhaust (mid-pipe/cat-back, i went with mac prochamber and mac cat-back) first then onto gears (3.73s - 4.10, depending on how much accel. you want to gain and how much top speed/ gas milage you want to lose) which I recommend you get done by a shop.