High Power vs. Low Power Model
 

I wonder what makes one engine higher power then the other and how much it would take to make the low power engine to the high power spec?

Electronics, Intake, ......??? It's the same engine right?

I would guess same engine, diffrent ECU tuning, one is rev limited due to the auto-trans, so it doesn't make the peak power of 250 horses at 8500, it just can't rev that high.

Both the auto and manual should make near identical power at 6500 rpm for example, but the manual can rev beyond that for a higher HP number, though it doesn't actually put out any more torque. HP = Toque x Revs

As we understand it, the only major change is the rev limiter.

---jps

So it will cost more money to take the rev limiter off?

better question styjan- how much is a new torque convetre or auto tranny when they blow up from going to 9000 rpm?

Is the low power auto only?

yeah in north america. japan definetly and i think europe get the option of the 4 speed auto or a 5 speed manual. but here it is 4 speed only.:eek:
edit: this is straight from mazda search mine or hercs post from the last 3 days for hercs link to three press releases. the third one is a 12 page pdf and on the last page is a chart show this and other stats.

As far as we've been told so far.

---jps

No worries then.

I don't believe so. The low-power motor produces more peak torque, and makes it at lower revs. My guess is that they've given it a slightly longer intake tract, or possibly even different port size and shape.

There was a good discussion at the below thread:
http://www.rx8forum.com/showthread.php?s=&threadid=1370

An excerpt: "The auto version has less horsepower because it can't rev as high as the 6-speed version. If anything, it has been "tuned" to have more torque at lower rpms rather than detuned. The 6-speed version has 3 different length intake paths and (if memory serves me correctly) the auto version only has 2 (missing the high rpm path). I'm not sure if the actual ports on the auto trans renesis will be made differently (higher costs). I am pretty sure that a simple change in the intake manifold is the difference."

The 2 intake paths for the auto have been optimized for different ranges.

Brian

And what reliable source has given you that information?

---jps

Try this thread. :)

The Hi-power has 3 intake ports per rotor, whereas the Standard power has only 2 per.

This comes right out of the presskit, page 28-29. Cool diagram of the intake system, too.

I'm still reading it, so I will add any other details I come across.

Edit: The variable intake control system opens and closes the secondary (and auxiliary ports). The Hi-power also has what they call a variable fresh air duct.

Take that with a big grain of salt, Hercules has a reputation of spreading around speculation as fact.

Notice that there weren't any HP/TQ numbers released with the press kit? It's because Mazda is still working on the numbers. I don't know what they're doing, or how close they are, but they did not have final numbers to release with the launch yesterday.

---jps

i was reading through the press kit, and indeed the intake runner between the high power and low power is different. the high power engine has these 2 extra 'auxilary ports' compared to the standard motor (think 5th & 6th ports on the NA 2nd gen RX-7 :D)

so yeah, it's not just a rev limiter, they also altered the intake manifold to gain top end POWA!

AND the side housings. Don't forget that the side housings will also be different with the extra port each.

Sputnik-

The HP and TQ numbers are mentioned twice in the press kit. Japan/North America high power version gets 247hp/159lb-ft of torque. You can see a chart on page 21 and a graph on page 23 that both indicate these values. I'm guessing that these numbers are pretty set.

The engine differences between the High and Low power versions that I could find in the press kit are:

Variable Fresh Air Intake (Opens above 7500RPM)
3 Path intake Manifold (Primary, Secondary and Auxiliary)
Auxiliary Airflow valve
3 intake ports per rotor (vs. 2 for the Low)
ECU programming to control the above equipment

(The press kit just says the Renesis has 3 injectors per rotor, but based on the photos I think the High power version has 3 fuel injectors per rotor, but the Low power only has 2. One per intake port. )

~Robert

I was told by good authority that they weren't set in stone yet, and even the press kit and websites still say "Provisional" next to them.

---jps

Do you think that this late in the game (production is supposedly going to start in February.) that they would actual increase the HP? I would think that they are probably in the final stages of long term testing and the provisional statement is just in case they run into something that requires them to lower the values.

Don't get me wrong. I'll take every bit of power they give me! :D

~Robert

I don't know when, what or why, if the change will be a little or alot, or if it will be more or less, but I have it on good authority that the numbers aren't set in stone yet.

---jps