232 Hp Rx-8?
#51
Originally Posted by Roaddemon
Now I'm thinking, if not for the rx8 safe mode on dynos, turbo rx8's making 240 rwhp are probably making closer to 260 rwhp. Anyone with a turbo can confirm this? Someone on here said they could easily walk EVo's and sti's with his greddy turbo.
Last edited by Ike; 01-07-2006 at 11:40 PM.
#52
Throw out all the SAE numbers, all of Mazda's old horsepower claims, and the dyno numbers. Trap speeds don't lie, and the RX-8 traps speed indicate it's putting less horsepower to the wheels than a 230hp car of its weight should. Hell, the RSX Type S which just got lowered to 201hp is faster (traps higher) than the RX-8. So either the drivetrain is eating up more horsepower than it should be thorugh its drivetrain, the '06 is making a little more power than the 04/05 due to some tweaks from Mazda, or the SAE numbers are still a little off.
As far as I know the only difference with the SAE testing is there are SAE certified whitnesses present when the testing is done. There is absolutely nothing to keep Mazda or any other manufacturer from making ECU tweaks or other small changes to the engine before testing begins (I hope I'm wrong on this). There's also nothing keeping manufacturers from finding a particularly strong engine to test. Not saying that's the case, but new SAE system is hardly foolproof. To me real world results is what really matters.
As far as I know the only difference with the SAE testing is there are SAE certified whitnesses present when the testing is done. There is absolutely nothing to keep Mazda or any other manufacturer from making ECU tweaks or other small changes to the engine before testing begins (I hope I'm wrong on this). There's also nothing keeping manufacturers from finding a particularly strong engine to test. Not saying that's the case, but new SAE system is hardly foolproof. To me real world results is what really matters.
#53
Originally Posted by Ike
Throw out all the SAE numbers, all of Mazda's old horsepower claims, and the dyno numbers. Trap speeds don't lie, and the RX-8 traps speed indicate it's putting less horsepower to the wheels than a 230hp car of its weight should. Hell, the RSX Type S which just got lowered to 201hp is faster (traps higher) than the RX-8. So either the drivetrain is eating up more horsepower than it should be thorugh its drivetrain, the '06 is making a little more power than the 04/05 due to some tweaks from Mazda, or the SAE numbers are still a little off.
As far as I know the only difference with the SAE testing is there are SAE certified whitnesses present when the testing is done. There is absolutely nothing to keep Mazda or any other manufacturer from making ECU tweaks or other small changes to the engine before testing begins (I hope I'm wrong on this). There's also nothing keeping manufacturers from finding a particularly strong engine to test. Not saying that's the case, but new SAE system is hardly foolproof. To me real world results is what really matters.
As far as I know the only difference with the SAE testing is there are SAE certified whitnesses present when the testing is done. There is absolutely nothing to keep Mazda or any other manufacturer from making ECU tweaks or other small changes to the engine before testing begins (I hope I'm wrong on this). There's also nothing keeping manufacturers from finding a particularly strong engine to test. Not saying that's the case, but new SAE system is hardly foolproof. To me real world results is what really matters.
#54
^^^ its more than just a witness. the old rules had some ambiguous things that are up to interpretation by the automaker. essentially a lot of wiggle room for companies to be overoptimistic. The new SAE net regulations are much stricter and eliminates a lot of the old loopholes and becomes more standarized. Its not perfect, but much better than before.
#56
yeah my theory is that the crank hp of the 2 cars are probably pretty close. in fact the renesis might just be the decisively better engine since its so much smoother. there might be something draining more power on the rx8 between the engine and the wheels than the s2k resulting in the real world performance gap.
#57
Well skeptics will always have thier 2 cents because they think they know everything about everything. I'm just happy to know the crank hp of this car. Since all cars are rated by the same system, power is all relative to the next car. Safe mode explains the dyno problem period. Trap times vary by conditions and do not accurately measure Hp. It's not an exact science. Try measuring same day/time trap times to other cars the same weight/tires and hp as determined by the sae. Then report back here with the results. lets be scientific.
#58
Originally Posted by Ike
Trap speeds don't lie, and the RX-8 traps speed indicate it's putting less horsepower to the wheels than a 230hp car of its weight should. Hell, the RSX Type S which just got lowered to 201hp is faster (traps higher) than the RX-8. So either the drivetrain is eating up more horsepower than it should be thorugh its drivetrain, the '06 is making a little more power than the 04/05 due to some tweaks from Mazda, or the SAE numbers are still a little off.
the FWD rsx should and probably does have less drivetrain losses than the RWD RX-8
#59
Originally Posted by Roaddemon
Well skeptics will always have thier 2 cents because they think they know everything about everything. I'm just happy to know the crank hp of this car. Since all cars are rated by the same system, power is all relative to the next car. Safe mode explains the dyno problem period. Trap times vary by conditions and do not accurately measure Hp. It's not an exact science. Try measuring same day/time trap times to other cars the same weight/tires and hp as determined by the sae. Then report back here with the results. lets be scientific.
There is a large enough sample of most cars that you don't need same day conditions. Besides, when I make my statement I'm using the RX-8s best trap speeds, not what the average person is getting. Also, that is a compeling argument for safemode. Ignorance is bliss.
#60
Originally Posted by zoom44
trap speeds dont lie- we can all agree on that. but what is trap speed an indicator of? whel hp or crank hp. also is there a formula that you use to find HP from trap speed?
the FWD rsx should and probably does have less drivetrain losses than the RWD RX-8
the FWD rsx should and probably does have less drivetrain losses than the RWD RX-8
#62
No, Your wrong on the safe mode. Rotary news explains even if you disconnect all sensors the car registers no feedback and something isn't right. It goes to a different map. the The new map makes everthing rich so no damage can't occur. The Emc changes to a setting that will handle conditions that negate safety sensors.
As for trap speeds, how can it possibley measure hp at the crank. hp is a measurement of how fast work is done over a given distance. Low tq needs high rpm to make time. Higher torque should get you there faster and at higher speed than low torque, depending how long it takes the low tq car to get up to it's rev range. Trap speeds are not reliable hp indicators. Not unless you know all the mechanical and natural conditions involved.
As for trap speeds, how can it possibley measure hp at the crank. hp is a measurement of how fast work is done over a given distance. Low tq needs high rpm to make time. Higher torque should get you there faster and at higher speed than low torque, depending how long it takes the low tq car to get up to it's rev range. Trap speeds are not reliable hp indicators. Not unless you know all the mechanical and natural conditions involved.
#64
Originally Posted by DrKillJoY
From what I understand the AT got some of its significant power bump due to the change in transmission choices.
The old AT were handicapped because they could not take full advantage of the RPM range of the Renesis.
The old AT were handicapped because they could not take full advantage of the RPM range of the Renesis.
#65
Originally Posted by zoom44
what is the formula and does it indicate BHP or WHP?
btw the advertised power still needs top be within 5% of the actual power
btw the advertised power still needs top be within 5% of the actual power
As for the formula now I'm not sure if it's WHP or BHP even though I said WHP earlier. The formula works sometimes and other times it really doesn't IIRC. When I say trap speed is a good indicator I'm moreso going by what cars with similar dyno numbers and weights trap. For instance the WRX traps around 94mph (maybe a touch lower than the 8 and weighs slightly more), it regularly dynos around 175-180whp on a dynojet.
Here's a link if you want to play around... http://www.ajdesigner.com/phphorsepo...horsepower.php
#66
Isn't the wrx awd? I thought it had a big advantage from a start. I'm surprised the 8 would stay with it from the dig. On a roll I'd give it to the 8. There's alot of obvious and not so obvious dynamics involved in track times and racing. That's what makes it so interesting as a participant and spectator sport.
#67
Originally Posted by Roaddemon
Isn't the wrx awd? I thought it had a big advantage from a start. I'm surprised the 8 would stay with it from the dig. On a roll I'd give it to the 8. There's alot of obvious and not so obvious dynamics involved in track times and racing. That's what makes it so interesting as a participant and spectator sport.
#68
Originally Posted by Ike
As far as I know the only difference with the SAE testing is there are SAE certified whitnesses present when the testing is done. There is absolutely nothing to keep Mazda or any other manufacturer from making ECU tweaks or other small changes to the engine before testing begins (I hope I'm wrong on this). There's also nothing keeping manufacturers from finding a particularly strong engine to test. Not saying that's the case, but new SAE system is hardly foolproof. To me real world results is what really matters.
#69
Originally Posted by r0tor
umm.. all the pieces tested come off of the production line
#70
Originally Posted by RX8-TX
Reason why the WRX gets better ETs than a comparable RWD vehicle with the same power output; however, it generally puts out a lower trap speed. Am I right this time?
With all the flashes that have gone on since the car was first released it wouldn't shock me at all if Mazda has extracted a little more horsepower out of the car from when it was first released. When I first test drove the RX-8 it was rated at 247, and I came back and said it felt like it was more like 220 or 225hp and then got flamed like mad. Looks like I wasn't so far off afterall.
#71
Originally Posted by Ike
I'm fully aware of that, which is exactly why the car was set at 238hp. Some people prebought the car at 250hp so Mazda did the math and 238hp is just slightly below 5% while 237hp is slightly above.
As for the formula now I'm not sure if it's WHP or BHP even though I said WHP earlier. The formula works sometimes and other times it really doesn't IIRC. When I say trap speed is a good indicator I'm moreso going by what cars with similar dyno numbers and weights trap. For instance the WRX traps around 94mph (maybe a touch lower than the 8 and weighs slightly more), it regularly dynos around 175-180whp on a dynojet.
Here's a link if you want to play around... http://www.ajdesigner.com/phphorsepo...horsepower.php
As for the formula now I'm not sure if it's WHP or BHP even though I said WHP earlier. The formula works sometimes and other times it really doesn't IIRC. When I say trap speed is a good indicator I'm moreso going by what cars with similar dyno numbers and weights trap. For instance the WRX traps around 94mph (maybe a touch lower than the 8 and weighs slightly more), it regularly dynos around 175-180whp on a dynojet.
Here's a link if you want to play around... http://www.ajdesigner.com/phphorsepo...horsepower.php
actually no- the reason they had to re-state it from the ADVERTISED PRODUCTION number of 247hp to 238hp is because 247 was NOT with in 5% but 238 was/is. that the 2006 models are ADVERTISED at 232 suggests that they are closer than 5 percent of the actual.
Trap speed is an indicator of WHP. It has been accepted and thouroughly examined since the late 50s or earlier 60s. the formula which is used is
((.00426 times x MPH) to the third power) times a weight of xlbs
darin and i had a discussion about this some time ago- https://www.rx8club.com/showthread.p...hlight=formula
to calculate the flywheel hp from that you have to know the losses thru the drivetrain in eitehr percentage or hard number. that is a huge debate in itself. some will choose to be on the exact number side "drivetrain A will always lose 25 hp no matter what engine it is connected to". some (including me) will choose the percentage side "it cant be an exact number because it is affected by rpm and rate of rpm change".
people tend to say that cars should have 15% drivetrain losses. well that seems optimistic. look thru that thread and i have shown examples of 17 and 19 percent. hell FWD cars should have less losses and they seem to have 13-17 percent fromt he ones i have looked at. i have seen figures as high as 25% for rwd cars(some of the newer limslip difs cause high losses). those run down tests on dynos are no good because they are slowing down and the losses are different (more) when accelerating (affected by rpm and rate of change of rpm).
and neither side will agree on the drivetrain losses- so we cant get anywhere that way. there is only one way to test the engines power- take it out of the car but keep allthe accessories on it the full exhaust too. test it on a standardised engine dyno that has been rigourously test itself. run several tests with the accessories all on adn then average them. funny that sounds like the SAE standard.
2 years ago some engineers submitted a paper to SAE on the renesis. in that paper they showed the output to be 231ps. thats 228bhp or guess what? 5% less than the advertised 238. im not suprised by the new number of 232
#72
Originally Posted by Ike
When I first test drove the RX-8 it was rated at 247, and I came back and said it felt like it was more like 220 or 225hp and then got flamed like mad. Looks like I wasn't so far off afterall.
#73
Originally Posted by zoom44
actually no- the reason they had to re-state it from the ADVERTISED PRODUCTION number of 247hp to 238hp is because 247 was NOT with in 5% but 238 was/is. that the 2006 models are ADVERTISED at 232 suggests that they are closer than 5 percent of the actual.
#74
I don't see why you people even care. It's the same car!! If you are so worried about a silly number for the engine you have been driving for the past X months / years, get rid of your car because you don't deserve it. There are a lot of people that would kill to get a car like the RX-8 (Myself included).
Anyways, the reason that the WRX and RX-8 have similar 1/4 mile times with different traps is because the WRX can launch a lot faster than the 8, resulting in a lesser 60 ft time. But after launch, the RX-8 can catch up because of gearing etc.
Anyways, the reason that the WRX and RX-8 have similar 1/4 mile times with different traps is because the WRX can launch a lot faster than the 8, resulting in a lesser 60 ft time. But after launch, the RX-8 can catch up because of gearing etc.
#75
Originally Posted by Beodude123
I don't see why you people even care. It's the same car!! If you are so worried about a silly number for the engine you have been driving for the past X months / years, get rid of your car because you don't deserve it. There are a lot of people that would kill to get a car like the RX-8 (Myself included).
Very well put!!!! As far as I'm concerned, it doesn't matter what number they attach to the horsepower. What matters is that I like the car and it suits my uses just fine.