1FooknTiteFD

this is what I have heard so far: Guy from vishnu got 157rwhp. But I also know of another guy that had his dyno tested at XS and got 185rwhp.

What other numbers have you guys been seeing?

Metallic_rock

I don't know what's going on with those particular Rx-8's, but the one I test drove was fast as all hell!! I was very impressed. With the salesman and IoTus in the back seat, I was doing 55-60 around 20mph corners and that thing accelerated quite well. I thought it was very impressive for the size and weight of it. (3800 lbs)

wwilliam54

rx-8 are 2900-3000 pounds not 3800

t-von

iTrader: (8)

Shame on you for thinking any "Rx" vehicle weighs that much I hope that was a typo.

t-von

iTrader: (8)

Thats what I think. I think the ecu is manipulating the electronic throttle. Here is a reply I left over at the Rx8 forum:

wwilliam54

yuh
i think it will be 10k before it goes off, let the engien get good an settled

im betting the they will start dynoing at 210-220 like they are supposed to and turn out to be the most reliable rotary ever

artguy

vishnu uses a dynapack yes? their numbers are always much lower than the other peeps like xs who use the dynojets.

regardless...when i heard what they were doing back at sevenstock a couple years ago..with the port size and move...i knew it would be a dog....

when does rikki get his? he should be able to dyno his at pfs..im sure he will...i would.

j

RICE RACING

vishnu's result = a 190bhp engine !

Most dynapacks RWHP figures when run in a "normal mode" can be multiplied by 1.20. My own car dynoed 472rwhp on a dynapack and engine power was near 565 to 570bhp (from my data). If his car was dynoed on a dyno dynamics in normal mode you could multiply the rwhp result by 1.36 factor which would bring it up to 214bhp (even so still a hell of a long way off) and both these dyno systems read LOWER than a dynojet when run in a "normal" mode.

This is a hell of a long way short of the claimed 247bhp !
And is LINE BALL with the numerous dynojet readings.

Mazda has lied to the tune of 30+bhp and it is a shame.
RENISIS sucks ***, said it from the outset when people were craping on about how much power these things were going to make.

I will go on record as saying that they will be one of the most unreliable NA rotaries too, 9400rpm is too much for them to handle for the long term. I will be very suprised if many see over 100 000 miles especially if owners often use the full rev range on every journey.

Very disapointing results thus far, and what looks like plain lies on the behalf of Mazda. I have NEVER seen so many excuses as have been thrown around for this cars lack of claimed power. Funny how 350Z's dyno spot on rwhp figures compared to claimed engine power yet Mazda are a LONG WAY OFF !

infinitebass

1. Everything I've heard about Dynapack's is they give higher hp figures than dynojets, and dynojets give higher hp figures than mustang dynos.

2. RICE RACING, I've seen a couple of times where you really seem to talk out your ***. Most cars usually dyno low until they are fully broken in, which can take up to 5000 miles. I know these do not have that many miles on them. Also, the 350Z's WERE dynoing lower than expected until they were broken in fully. Showed a big difference going from ~1000 miles to 3000 miles.

3. Explain how 9400 RPM's is too much. They were DESIGNED for that. Just like the S2000 was DESIGNED for 9000 RPM's. Can you honestly say you know more about designing engines than Mazda?

You make all these claims, yet nothing to actually back the up. No reasons as to why you think that Mazda "lied" about the HP, or why they can't handle 9400 RPM's, etc.

I think you're talking out your ***, and will be proved wrong pretty quickly.

Blake

RICE RACING

Blake you need to listen carefully to what I'm about t say to you.

GO FARK YOUR SELF !

I have dynoed on a dynopack, have you ? NO by the sounds of it.

I have seen MANY dynojet readings, and especially how they corelate to 3rd gen stock cars so I think we all know what factors they run at !

Time will tell about the durability of these engines !

Time has already shown that they are low on power, NO EXCUSE offered by either yourself or the many others who have commented will make up for the loss of power in these engines compared to the claims made by Mazda.

Now go back to your moms *** and stick your head back up it before you insult me with your 2 buck opinions you **** smoker

Again 1.2 is the accepted factor used to multiply RWHP dynopack figures to get estimated BHP, 1.36 is the factor used for dyno dynamics & about 1.25 is the multiplication factor used for dynojets.

ALL RX8 dynos offered so far are ALL VERY LOW no matter what system quoted, NO AMOUNT OF BREAK IN will solve this LACK OF POWER compared to factory claims .......... PERIOD !

Rotary engines go on a down hill slide after the first 600 to 700 miles of break in with regards to power output. If it dont make its claimed power now then IT WILL NEVER MAKE IT.

Metallic_rock

that's what it said on the door - no typo

RICE RACING

I will answer the no insulting part of your responce with some facts.

The geometry used by Mazda in the Renisis is EXACTLY the same as a normal 13B.

Apex seal sliding velocities are therefore the same at similar engine revs betweent he two engines, ANYONE who has experience in building and running these engines will tell you that the amount of apex seal wear and rotor housing wear is plain huge when revs start going over 8000rpm, so much so that you get a MASSIVE reduction in life of these components when using these elevated RPM levels for a long time. It is proportion to LOAD (gas pressure or power) which pushes the seal up hard against the housing mostly then secondary loadings are assosiated with weight of the elements. The amount of wear when using "normal" materials as Mazda have done witht he RENISIS is HIGH at these high RPM levels. So much so that if the engine is used especially as it is needed to be to 9400rpm to get full performance that they will wear out fast due to the speeds of the seals travel along the rotor housing surface with the associated loads present at 214bhp !.

If it is used "often" to its FULL potential it will not make 100000miles, I will bet anything you want on that If owners use LOW revs and the resulting lower power (like the old 6 port engines then yes it will do alot more miles before it will **** its self.

I will guarantee you that if that engine is specified up to 247bhp as it should be & used often up to 9400rpm, it will not be durable. It will take along time for owners to find this out, but like I saidquite a few of them will be babying there cars and not beating on it, for those that are HONEST with their usage and realy push the engine as its designed they will find out in a few years just how much wear is associated with those RPM levels and 13B engine geometry.

That is what Mazda are banking on, it takes a long while to do the required miles and also new owners are not that hard on their cars either, so it will take a little while for things to become apparant, when they do you can dig this thread up and re read the wisdom in my own little opinion

Resource

I'm pretty sure or atleast have heard that the Z06 computer does something so that it's full potential won't be unleashed until a certain amount of miles. This is the only reason I could come up with that the rx8 is weak sauce. Nothing mechanically could cause this like the infamous "the seals need to be broken in".......pshhh!

j9fd3s

iTrader: (3)

keep in mind rice that the apex seals are shorter in the renny, and presumably lighter

mike

RICE RACING

We still have lots of other elements in the engine, side seals corner seals.

Side seals especially wear badly or I should say allot when rpms are elevated too, they constantly move from one side to another "pumping" the corner seals, these clearances can and do become quite large over time and as you know all these things cause losses in power due to pressure loss from the chamber.

Either way wear will be high on all elements if 9.4k is used regularly.

My only point on the ECU "story" is that if you ask any Mazda dealer who has been brought up to speed on the RX8, none of them are aware of any such settings for that car/engine. Based on this then it looks like a strong possibility that the engine is indeed under rated.

Like others have said, rotary engines when assembled from new parts and properly clearanced seals etc will develope their best power before the 1000 mile mark for sure.

At this stage there is no logical reasons as to why ALL the cars tested are delivering consitently lower than average dyno results compared to what the factory claimed engine power figures should be.

Anyway as it stands the pattern is consistent, the RENISIS is strugling to get near 220bhp let alone the advertised 247bhp. Our Australian market models are rated at 237bhp due to tighter emmisions tune, it wil be interesting when some of these make it to a chassis dyno

Resource

I predict 35 hp at the wheels.

Carl Byck

do I hear 34?

RICE RACING

RX7 RAGE

iTrader: (22)

damn..i hope this does not signify the end of the rotary engine.

RICE RACING

I would not go that far.....but !

When you look at how much power it is delivering to the ground then look at how much fuel it consumes to generate that power IT LOOKS BAD

Jury is still out on long term durability, so I hope that this is ONE saving grace the RENISIS has, but I doubt it. Time will tell

RICE RACING

RENISIS is very gay when you compare it to this !

http://www.dynospotracing.com/s2000.htm

http://www.dynoperformance.com/searc...ils.php?ID=468

http://www.importtuner.com/tech/0108it_pps2k/

The RX8 is along way short of its claimed power, if others can deliver then why not the Mazda ? This is why people are making a big issue of it.

Hmmmm, another 600cc capacity and its still cant match the 2lt Honda power or the fuel economy, Mazda should be ashamed

Slacker7

iTrader: (2)

Rice racing,

When you talk about wear at the rotor tips you gotta consider acceleration rather than velocity.. this doesn't really matter because the accelerations should be the same at a given rpm due to the same shape of the rotor housing like you were saying. However, Mass is a very important aspect and should not be overlooked. When talking about friction normal force, N is very important F=ma. The rotors in the renesis are 14% lighter than that of the 13b-rew. So that would leave room for the motor to have a higher redline with the same amt of friction at the apex seal tips. You say that you have massive wear at the apex seal tip in previous 13b engines at above 8000rpms.. but it might not be true due to the rotors being lighter.

You also mentioned about loads at the apex seal tips.. Remember that in the new renesis the peripheral exhaust ports have been moved to the side housings. This practice reduces stress concentrations on the apex seal tips because it doesn't have to be supported by just two bridges over the exhaust port. Moving exhaust ports to the side housing also exposes the apex seals to lower temperatures.

The new engine also uses 2 oil injectors per rotor housing which is believed to improve lubrication of the apex seal tips

Also an additional side seal has been added to improve sealing. With an additional side seal it is intuitive that all the other side seals will have less load on them.

RICE RACING

Slacker 7

Your points are many.

The weight of the rotor is not a factor in apex seal wear !

SLIDING velocity is a great factor, the apex seal hits a peak at the tips of the "figure 8" and slowest points at the mid sections, it is constantly accelerating and decelerating ! (Ever noticed how plating "peeling off" rotor housings is greatest at the points of highest velocity ? "top and bottom of rotor housings")

The MAJOR load is due to gas pressure, weigh of the element and spring is secondary. Very distance secondary in the High pressure regions !

The extra side seal is for the exhaust, it does NOTHING to stop chamber leakage from one chamber to another or into the clearance volume between the combustion side seal and the oil control ring seal protector !

Nice try, will admit that the extra oil injection port is correct from what has been discussed but ALSO oil consumption is down, which means there is less going to the same seal cross sectional area.

This engine will need to prove its durability, but I will not be waiting for the results as its a forgone conclusion in my books, use it hard and often and you will be rebuilding it sooner than you think

Rotor weight has nothing to do with apex seals or side seal durability

If you dont believe the massive increase in wear on apex elements (and side seals/corner seal clearances) then thats up to you, realy soft apex seals show just how significant this can be increasing engine rpm from 8500rpm to 9000rpm can reduce the life of some of these rotary engine components by great amounts. Again I state this from years of pulling these things apart and I truley believe its a geometry issue, nothing has realy changed in the RENISIS and the materials and techniques Mazda use are nothing special so therefore we should not be expecting any miricals from this engine type. I have been saying this for over 18 months.

First the lack of power has been proven, next it will be the durability for hard users even at the under rated power. Hope not but I think given Mazda's record the rebuild industry will be doing a roaring trade

No7Yet

Rice Racing,

1) Especially since the engine geometry has not changed, the derivative of the compression chamber volume over time hasn't changed. This means that, with compensation allowed for the increased VE of the engine, it is under no increased gas load whe compared to any other rotary engine. You've got a point about wear occurring where apex seal velocity is the greatest, but you're forgetting that the mass of the apex seal influences the centrepital force exerted upon the seal, and thus on the rotor housing. If you reduce the apex seal mass, you decrease the force, and thus, the wear. We can then reduce the only significant factors here to apex seal mass and RPM. I'll then add that Formula Mazda racecars are known to go multiple seasons between rebuilds while spending almost all of their running time at or near maximum RPMs (about 8000 RPM) and maximum power output.

2) The oil injection points have changed and oil consumption is down, yes. The reason it's down is because no more oil is being slung off of the apex seal while it passes over the exhaust port. This was a significant source of HC emissions in the previous rotaries. The simple fact is that the apex seal is never exposed to temperatures that would cause autoignition of the oil, and the oil is not being lost out the ports. This means that the oil is being retained better. I would venture a guess that in combination with improved apex seal and trochoid housing material, apex seal wear will be negligable over one hundred thousand miles or more.

3) I'd like to see your sources concerning Mazda using "nothing special" concerning their materials. It is my understanding that Mazda's materials technology has continued to develop at an evolutionary (not revolutionary) pace. Thus, no miracles can be expected, but it's niave to assume that nothing's improved since 1986.

4) Mazda has not yet made any official statement wrt the causes of the low power output. It is my personal suspicion that the ECU is limiting throttle opening during an initial break-in, but that's pure speculation. The simple fact is, I don't know, and neither do you.

Brandon
BR7 Racing

RICE RACING

Brandon, gas pressure in combination with 9400rpm engine speeds = increased wear.

I dont care how much oil you inject into it or retain The corner section will still tear the **** out of a housing that has done minimal service just as it has done through the history of mazda rotaries that use that sealing method. 9400rpm will greatly accelerate this.

Ferrous based sealing materials, Nikasil type liners show me the evolution ?

Your ECU speculation is just that, there are no excuses for the consistent low numbers, but I am sure if you spent 30k you could think up quite a few

Break in "de tune" is a falicy, Mazda technicians who service these cars have already confirmed that.

Time will tell, multiple seasons of racing means **** ! Tell me how many racing miles it is doing and I will listen to what you have to say Better yet I can tell you if you like