AsianStyle

I was wondering if a simple ecu upgrade would happen on the rx8 and what the gains would be. The rsx does a quarter mile in 16secs, but many people state that with just intake,exhaust, and hondata=ecu swap, they have the ability to do the quarter mile in the low 14s. Whats even more interesting is they gain the ability to rev up to 8.9k rpms and the only problem the cars seem to be faced with is a little loss in mileage, no reliability loss or loss in life of the engine.

Sputnik

The benefits of an ECU upgrade won't be known until someone does some testing.

As far as what people claim about their little bolt-on mods, always take that with a grain of salt.

As far as revving the engine higher, on an engine that can normally last 150K+ miles, it will take a little while before someone can claim that there is no loss in reliability or shorter life. Another reason to doubt the reliability of such "claims".

---jps

AsianStyle

I don't doubt the rsx's performance gains with the ecu because they have time slips and videos to back it up. I just don't believe the reliability issue of being able to rev higher then the car is made for and have useful power in te higher revs. The ecu upgrade is also suppose to make their vtec kick in earlier.

OrangeBingo

My father bought an '89 SHO when they were brand new and as soon as it was broken in he replaced the exhaust and installed an ECU. One thing that the ECU upgrade did was to raise the rev limiter. The car only has about 16k on it so I don't know what the long term effects will be, however, the first time I took it up to 8 grand I forgot to turn off the A/C and promptly blew the seals.

AsianStyle

O that must suck yea I just went to the actual hondata webpage and I found out the 8.9k is where the rev limiter kicks in. 8.6k is the redline and 8k is peak hp(they had a dyno). It looks like with ecu and intake the car gets 190whp and they mention LITTLE more hp with exhuast and headers to create better air flow. So I'm not sure about the people who state 230-240whp because thats a significant gain not a LITTLE gain that the webpage themselves mentioned. Maybe they did some weight reduction like taking out back seats and etc. Another thing I found out that was very very interesting is how the webpage states that the higher rev is at the owners risk haha. They state they wont cover any issues caused to the engine because of high reving and how honda wouldn't cover it in their warranty either. I guess I was right about reliability of the higher rev limit but I wonder if the sooner vtec has any reliability problems. If it doesn't wouldn't the rx-8 also gain alot by the ecu swap because the vtec is simillar to the power ports in the rx8 so making the power band start lower without any bad effects would be a very good mod at its $600 price tag.

babylou

If there was a power band advantage to opening the bazillion intake ports the Renesis has at different RPM's Mazda would have coded the ECU like that from the start. Any tack on device that only controls the opening of the ports will be a waste of money and will hurt the power band.

AsianStyle

The ecu swap would also improve hp not just adjust the power band, but yea I agree with you about why Mazda wouldn't do that from the start. Then again the rsx's ecu changes its vtec time at the revs and hp just by a ecu swap. Why wouldnt Honda just kept the rsx like that from the start? Maybe it really does have reliability problems or for mileage because that is suppose to drop with the ecu swap.

Sputnik

When you are looking at this kind of thing, you have to remember that Honda designed the car for around-town performance, good gas mileage, decent sound levels (for the general public), and reliability for gas and environment situations that the car may find around the country. When you are modifying the car with things like exhaust, ecu, and intakes, you aren't magically gaining something, you are making trade-offs. While most of these trade-offs are acceptable to those who want to modify the car, it is not for the general car buying public, and that's why the car manufacturers do things how they do.

For example, with basic ECU changes, you change rev limits, vtec points, and timing. Timing advance will give you a nice increase, but at the risk of detonation from poor gas. So, if you always get premium gas, that's a tradeoff that most gearheads don't have a problem with. Increasing rev limits stresses the engine internals. This is not something that will show up in the near future (unless you really increase the rpms), but it will cause the engine to wear out sooner. With the VTEC points, you might get some increases when running the car on the dyno or down the strip at WOT, but it messes up around-town and off-throttle drivablility. While the drag racers will want to sacrifice a little around town for a faster run on the strip, others would rather have a car that drives better around town.

Same thing goes for something like the exhaust system. Bigger is not all around better. Even considering nothing but WOT running down the strip, there is a point where a bigger exhaust actually hurts performance. From the factory, the exhaust is sized so that you lose a couple of HP up top for a couple of lbs torque down low (where we all drive on the street), and for more mpg when cruising down the highway at 65 mph, or caught in street traffic at 30 mph. Again, some people are perfectly happy giving up low end torque, off-throttle response, and some gas mileage, for that little bit of power up top for the strip or dyno. But as much as their "but-dyno" might tell them that they've gained all around power, they lose power down low, at cruise or WOT.

Then there are things like mufflers that are restrictive for sound reasons, and changing them out just to remove that restriction might help all-around.

Then consider how the car is marketed. For example, the Civic is supposed to be an inexpensive, reliable, frugal car. And so, the exhaust and intakes are sized for every last mile per gallon at cruise and idle, so they are as small (which is also cheaper in mass-production) as you'll see. So changing the exhaust and intake out on the Civic will offer a bigger increase in top-end WOT performance than on other cars. The RSX is more of a "sporty" car, so you won't get as much of a kick out of changing out intake or exhaust, but you will still get some out of it, with certain sacrifices, of course.

Anyway, that's why the factory doesn't seem to have things "optimized" from the start. It's because they are "optimized" for their legal requirements and for the biggest portion of their targeted customer base, not for what is the most desirable for you or I.

---jps