View Single Post
Unread 11-29-2011, 10:47 PM   #3
elemein
Senior Member
 
Join Date: Aug 2011
Location: Mississauga, Ontario, Canada
Posts: 385
Rep: 19 elemein is on a distinguished road
Default

Speed Demon raises a good point, but it'll also kill a bit off your low-end torque to contribute it to your high-end torque. While this does improve fuel economy and does TECHNICALLY add horsepower, it will make your car harder to use in the lower RPMs.

Which raises the question; when merging on the high-way/any situation where you want more horsepower; do you want it in the low RPMs where the fuel economy to horsepower ratio is higher, or in the high RPMs where the fuel economy to horsepower ratio is lower?

If you need most of your power in the high-end RPMs, then Speed Demon's advice will be totally fine and sufficient and wont cost too much.

If you need it in the low end, then that's where I can help you (I personally am not a fan of exhaust-system modding as it moves the torque and power bend. Not desirable as it makes the car a little harder to manage at lower RPMs the bigger you make the exhaust system).

A cold air intake is a waste on a ford focus. They're expensive for the power and really only useful if you want to squeeze out every last milliwatt of power out of your engine. Most of us wont bother with this easy yet expensive for the power modification.

Weight reduction is a great idea. Though you seem to have some misconceptions about this; it does not even touch your horsepower or torque. It DOES indeed raise acceleration and handling characteristics. Heres an example; Imagine you're in a grocery store with a shopping cart; at the beginning when your cart is near empty, it is very easy to accelerate and has nimble handling characteristics, but as you add more things to it, it gets heavier and more clumsy. That is very good example as to what your car needs to do. Weight reduction doesnt add horsepower, it makes the horsepower you DO have more useful. Also, weight reduction helps fuel economy since your engine can rev-lower to move the same distance with lower weight.

Also, a supercharger and/or turbocharger upgrade is definetely overkill just to add on 15 more horsepower (your car has around 130 hp last time I checked. 15 hp is around 10%), you'll probably get more like 40-60 hp out of those, and YES, you will hurt your fuel economy. Not as much in the low-end, but then again, you dont make much power in the low-end with superchargers or turbochargers.

Also, you cant "upgrade" your engine with VTEC. Those come built-into HONDA engines. Not fords. This is what you call an engine "swap". And yes. It is extremely expensive for only 15 horsepower, and will turn your fuel economy to whatever the engine you put in the car to. It wont be the usual "amazing" Ford Focus mpg. It is also not only expensive, but changes the car totally, is VERY difficult for a "car modding noob", is very time-consuming, and if you get a mechanic to do it, will drain you of all your cash. Not worth it.

So, what can you do?

As said previously, if high-end power is what you want, the exhaust-system route is perfectly fine for this.

Though there are a few routes you can go down when wanting to make your car faster for a specific reason. I have three routes for you that I'll call out according to main idea.

I'm gonna call them "Weight Reduction", "Transmission Re-Gearing", and "Engine Packing".

Weight Reduction is obvious. It is free, and NO, adding carbon fibre to your Ford Focus is not only tacky, but doesnt yield extremely high-benefits for the big price tag. I reccomend taking out all the useless crap you dont need for starters. If you have a part of your car or function you dont need; trash it. Then I'd move on to a little more extrenous weight-reducing forte's, such as removing the seat belts from those rear-seats you took out (if they were pillar-mounted seat belts.), taking out some sound deadening, maybe cleaning out your trunk and the spare-tire compartment. Why not change your radio antenna from that gi-freaking-nourmous thin one to a "stubbie"? You'll get better reception, lower weight, and better aerodynamics. If you're interested in the fantastical route of weight-reduction, then Speed Demon is a proclaimed knowledgeable source of car-anorexia who will happily help you.

Then we have Transmission Re-Gearing. You said you have a manual transmission? Good. It'll be great to regear. Now ask yourself something quickly; what gear do you merge onto the highway with? Third? Fourth? Fifth? If you're merging onto the highway and at high-RPMs and is still not satisfied with the car's power, then a regearing might be in order (though here's an important bit. If you merge onto the highway and your tachometer is NOT at high-end RPMs and you're asking about adding horsepower, then jump into your car right now, go merge onto the highway, but this time, use your car's high-end RPMs. If things went much better, then you dont need to add horsepower or anything, if you already use your high-end RPMs when merging, then read on.) Now, I'm not going to go into depth here, but lets simplify your transmission ratios here. Basicly; a lower ratio = higher top speed, BUT, slower acceleration. A higher ratio = lower top speed, BUT, FASTER acceleration. Transmission work can get costly depending on your car, but it should be pretty manageable for your car depending on your budget. Basicly, when you regear your transmission, you're changing the rate at which your car accelerates and also at which speed it needs to switch gears. So go back to the question; what gear do you use when merging to the high-way? Third? Regear your third gear to be a higer ratio for faster acceleration (though also a shorter shift-point). Use your fourth gear? Then change that one out to be a bigger ratio. Fifth gear? You guessed it! Change it to become a bigger ratio. Thats all there is to it when we deal with your problem. Though bear in mind, a bigger ratio = lower top speed/higher accel., smaller ratio = higher top speed/slower accel. DONT forget it.

Then we have Engine Packing. Which is what you wanted in the first place. Lets just throw more power at your engine. First thing's first; there are very cheap things you can do at first to get some more power out of your engine before all those expensive do-dads. First, lets get you a K&N air-filter. Everyone loves them. Not a big HP increase (realisticly only 1-3 HP), but they're dirt cheap, are reusable, get you about 5-10% better fuel economy, and as said before, everyone loves them, and for around 50 bucks, where can you go wrong? Next, lets get you some performance spark-plugs (and wires too!), this is also dirt cheap, helps your fuel economy a bit, and adds an extra 1-3 HP, everyone does these, and again, for only 50-70 dollars for performance plugs AND wires, where can you go wrong? Now, those things are all fine-and dandy; and they do noticeably help, but lets get into some funner stuff. Firstly, make your throttle-body bigger. Simple, cheap, and guaranteed to improve power and acceleration up to a certain point (once your throttle body becomes bigger than all your intake runners, it's quite pointless to make it bigger.) Also, lets invest in a fuel-rail if you dont already have one. This helps fuel get to your injectors with optimal pressure, this can easily net you 4-5 HP if you dont already have a fuel-rail & Fuel-pressure regulator (which you probably do, but they may be seperate or not performance-based). Speaking of injectors; get free-er flowing ones. It lets more fuel run to your engine faster, cleaner, and with more presure; so that's an easy 3-5 HP too. Why dont we also get a high-flow fuel pump to run those injectors? A good idea; the two upgrades naturally help eachother. Also, if you're feeling adventurous, why not reflash your ECU or tune it? Your ECU is compatible with OBD-II regulations, so tuning it should be a breeze, the tools are also pretty inexpensive. With the tools, you can tell your computer how much fuel to inject at what RPM in what gear; when to send a spark to the ignition, and lots of other fun stuff to move your power-bend into the lower, mid, or higher-end (all to your choosing). All this stuff will either improve or not touch your fuel economy at all, and all these together will not cost as much as a turbo or supercharger; all are easy to install; will make your engine more reliable or wont touch reliability, and also will all make more than 15 HP easily.

You can do one route, or a combination of all them, or just two.

Sorry for a long post, I like to get detailed; the more information you give us, the better we can assist you.

Welcome to Carforum.net, you've entered the fun and intriguing world of car-modifying Hope you stick around!

elemein is offline  
Reply With Quote