2003 Corolla S - How Can I Improve

#1
So I have a 2003 Toyota Corolla S 5-speed with 161k miles on it. The past owner took incredible care of this car and it still runs great (knock on wood), anyways stock it comes with 130 hp. I put a cold air intake and a magna flow exhaust on it so i probably have almost 150 i hope. I use 5w-30 oil, and have brand new pirelli tires on it as well. I was wondering what you guys suggest i can do in order to gain more hp out of my corolla s? Its a very fun car right now with the two mods i have on it, and i get 31 mpg. I just want a little bit more power so what are your thoughts on what i can do?
 
#2
Cold Air Intake and Exhaust won't give you that much power. You're probably more in the neighborhood of 135, tops.

Your bottleneck is in the heads. Valve timing and valve diameter (as well as port and polish) will take more kindly to a less restrictive intake and exhaust system. The stock equipment is designed to handle the stock heads, so adding intake and exhaust stuff doesn't do much.

There are turbo kits out there for that year Corolla, but you are looking at close to $4k, and you would need a clutch and a limited-slip differential to make use of the power. People are dropping 200 horses at the wheels with them, which is roughly 240 at the crank.

Other than that, not much else you can do. There are no bore and stroke kits for these engines that I'm aware of, although there are cam kits that you can add in addition to your intake and exhaust that will help you see the benefit of adding them.

Just keep in mind that anything you do from the throttle body to the exhaust ports on the heads is going to require tuning by a professional so that you don't destroy the engine by running lean or foul it by running rich.
 
#3
Hey are you Armenian? haha that last name sounds like it, i am as well ha. Thanks for the advice i was thinking of putting new headers and injectors on it but the more i think about it.. its not really a race type of a car and is meant for gas mileage and good transportation which it does nicely. so far with the intake and exhaust i get good power within my first 3 gears. then when i shift to 4th and 5th.. it looses power greatly. some extra power on 5th gear is all i really want
 
#4
Yup, Russian-Armenian.

A Corolla isn't a race car, but I would still turbo one just to make Civic Si and Focus ST owners weep.

Toyota should have considered a 180 hp engine in the S. Leave the L, LE, LE Eco for fuel economy conscious and make the S what it begs to be.
 
#6
If the exhaust actually increases flow, and the intake is actually a cold air intake (more so than stock), then I'd say you might have 140hp.

I'd look into a lightened flywheel, it will make 1st and 2nd gear feel noticeably faster. Only thing is that it will make it easier to kill (needing more clutch and finesse to start from a standing stop) and would be a lot of work to replace yourself and expensive to have someone else do it.

If you have steel wheels, then consider getting a set of lighter weight rims that are the same diameter or up to 1 in taller (to allow lower profile tires). Reducing any weight that rotates will be about doubly noticeable than reducing the overall weight of the car. Don't just get aftermarket wheels, find out what wheels are actually lighter.

Consider other weight reduction. I don't really have suggestions because I don't know that car.

In the end, a turbo is really the sensible option if you're serious about getting more power out of your corolla.
 
#8
Yes, most significant weight reduction I would not recommend for a DD. But it's amazing the pounds you can shave with no drawback if you are in the right mindset.
 
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