DonG35Miata

I already started a poll on this:

Would you have preordered at 220hp?

As of this posting, 67.13%, around two-thirds have indicated they would not have preordered a $30,000, 220 hp RX-8.

RICE RACING

Sounds very bad to me.

Why cant the RX8 match the smaller capacity S2000 which puts out well over 200rwhp from only "240bhp" ?

I will definatley wait a fair while till this issue gets clarified before I think about the RX8, I love the car but that is alot less power than claimed ?

Magic8

I don't know if this will help anyone, but FEED did dyno their RX8. The article didn't show any scales on their dyno results, but apparently they didn't raise any issue about a lack of HP problem. I can't read Japanese, but I wonder if that article raises any issues?

The following is the article I am referring to:
http://www.rx8forum.com/showthread.php?threadid=6259

The article says that they were able to get 12ps from an exhaust upgrade. Heck they even have pictures of their RX8 on a dyno.

Magic8

Edit
I just read the article more closely, they did mention 213.8 ps. I am guessing this figure was after the exhaust upgrade. The HP was mentions on the second page in the paragraph next to the dyno graph.

RobDickinson

Well 213-12 = 201 so sounds about right for the 247bhp car?

altaic

201ps * 0.98632bhp/ps = 198.2503bhp

That's a bit far from 247bhp, no?

My take on the whole lack of hp thing is that Mazda is running it rich on the high rpms until it's first or second scheduled maintenance, where they'll reprogram the ecu's fuel maps. It's possible they are still working on finding the optimal map, taking the break-in into consideration. Either way, the most we'll hear is that the car gains more hp the more miles you put on it. Someone should be sure to dyno before and after scheduled maintenance.

My basis for this theory is Paul Yaw's findings, that it runs "pig-rich by the time it reaches 8,000 rpm." It'd be nice to dyno while tracking air flow and F/A ratio by rpm, though, just to see what the F/A maps look like.

BTW, I don't actually know anything. I've been reading this board and various articles, and things seem to fit together, so I decided to put my thoughts forward.

P00Man

lol, thats a lot like me...

in another thread BOOSTD7 found out that the engine has no problem putting out the 250 in the mazda racing series. so, like he pointed out, it is not related to the engine and is in all likelyhood an ECU "problem"

i think it is most likely fuel maps, like many have said

gettingan8

What are fuel maps..could you explain them please.

thanks P00man

P00Man

i dunno what they would be exactly but from what i can gather...

they are "maps" if you would, that the ECU uses to regulate the Air/Fuel mixture in the engine which is developed to acheive a certain goal, say maximum power or maximum efficiency or what have you, which would be determined by R&D specialists and then given to the programmers to code for

jmanolov

Are you sure the Star Mazda Series use the exact same configuration? Exact same intake manifold? Exact same throttle body? etc. It might be only the ECU, it might be something in addition too. We'll have to wait and see what happens. At this flow of dyno charts Mazda should answer soon

altaic

Actually, now in skeptic mode, I'm a little curious: Paul Yaw, I was wondering how you discovered it was running rich at 8000 rpms; did you measure it yourself, or did you get that information elsewhere?

Thanks.

wakeech

dude, you can see that from the first dyno plot here (it was a Dynojet, had the Lamba pick up), where it was running really rich in the upper half of the rpm band.

edit: bam, first page of this thread, second post (1stRX-8's dyno plot).

A/F ratios are >13:1 after about 5.25k rpm

altaic

Woops. It sort of got lost after reading so many posts on this subject. Thanks.

86rx7

The s2000 uses CV joints insted of u-joints on the drive shaft, making it more efficent.

neit_jnf

Actually, I believe the one-piece carbon fiber drive shaft used on the 8 to be more efficient. This is only my opinion as I don't really know anything about the efficiencies of either one.

Skyline Maniac

So.... what's going on with the power issue now? Still waiting for Mazda to answer to the inquiries or just give up, believe the 247hp and brush the dyno data aside?

Hercules

Unlike you Skyline, we can enjoy our cars even if numbers don't make us the best in some category.

It will be resolved when it's resolved. Since you're not doing any detective work about this, nor do you have any vested interest, please just wait for an answer like we all are. Not like it makes a difference to you anyway.

Skyline Maniac

Unlike you Hercules, most owners and potential buyers do care about Mazda's claim since nobody should get a 215hp car when they paid for a 250hp sport car. If you really don't care, then keep dreaming~

RX-Nut

True.. we all care.. owners or not.. If somehow someway we were shortchanged, intentional or not, we will find out eventually. Sooner the better. I just hope for the best..

As we know, Herc has a way of making things sound snappish, I'm sure he didnt mean it.. We love him that way :D

I promised myself not to get in this thread, but I couldnt resist. I just want a peaceful resolution to this issue, not petty lashing at each other.

Hercules

Hey, if it's below their published specs then I know I'll be compensated for it in some way.. so I'm not worrying terribly.

omahawk

Sorry if someone else has posted something similar. I have been out of town at a family members funeral.

I emailed Mazda last week and they replied with the following...


Thank you for contacting Mazda North American Operations. I appreciate
the opportunity to respond to you.

In regards to your question on the horsepower in the RX8, Mazda is
aware of what has been posted on the RX-8 Forum and we are currently
looking into the matter. However, we stand by the current stated power
levels: 247hp for the manual transmission cars and 207hp for the
automatic cars.


I asked for further explaination but did not receive any.

BRealistic

Not to ask a stupid question (heck, all my questions seem stupid I guess)- but exaclty who has contacted Mazda about this? And who in the Mazda USA organization did they contact? Just curious.

Also, did the people running the dyno verify that the throttle was reaching WOT? I hear the floor mats ride up sometimes.:p

Skyline Maniac

No no, you ASSUME you will be compensated for it. If everyone who owns a RX-8 deals with the power issue the same way as you do*, Mazda won't have to do a damn thing, since everyone is already happy. What's up with the compensation? It's not about screwing up and then having to make up for it through bribes. Like I said, you guys need to speak up, start e-mailing media and contact Mazda USA regarding this issue to get a quick resolution. If I was in your shoes, I would rather sell the car back because it's more about faith than 'how much discount I get per hp that's missing)

*Judging by your posts, it seems that you don't care about the power loss since the car is fun to drive. This sit back and relax attitude won't motivate Mazda to solve any problems anytime soon. I assume you paid the full MSRP for your RX-8, so like everyone else, you deserve what was promised to you by a manufacturer. No matter how cool you try to act and how you try to justify 'I don't need all 250hp'; it's not a matter of what you are willing to live for, it's about what was promised to you and the failure to deliver on that promise.

Quick_lude

It's not a "floor mat wot" problem.. :p There have been at least 4 or 5 dynos of different cars with various miles on the odo. Combine those results with 15 sec plus 1/4 mile times for the 247hp 6MT car and obviously there is some power missing at the top end. Look at the dyno graphs in the R&D thread in the general section. The torque seems to "disappear" around 6500rpm and thus hp is affected.

SlideWRX

For a little perspective:

The WRX is rated at 227, puts down ~160-170 to the wheel, 60-70 hp loss. We have AWD to deal with, so ~25% loss makes sense for us. Haven't seen a 2WD manual with more than 15% loss.

A/F stock for the WRX was below 10:1! Tuned, it sits around 11:1. With water injection, we barely hit 12.5:1. Yea, I know completely different setups, but food for thought.

Our ECU is very adaptive with the ignition timing and A/F - After an ECU reset, letting the car run at mild load around 4000 rpm for 20 seconds will change the dyno results by 10 hp. The ECU has an ignition multplier it uses to do crude tuning (in addition to fine tuning by rpm). Jsut letting the ECU change that multiplier under light load for a short time gives 10 hp.

There are also high and low detonation fuel maps. changing from one to another changes A/F by about a point (10:1 to 11:1).

Tom

Lensman

This may be nothing and almost certainly was taken into account when the various cars were dynoed but on page 5-4 of the owners' manual it states: