gxsilver

did a base run today on a dynamic Dyno.........


car did 184.4 hp

not to bad I guess, since I came from a 2003 mustang Gt making 400hp


but this car does get the girls to look !!!

(i had a pretty, young bank teller start flirting with me in the drive thru line---the mustang never got that !!! )

rx8pilot

I'll go ahead and say it.. because rest assured..someone will if i don't..

POST PICS OF THE DYNO RUN...............................please

and what gear did you dyno in? conditions? etc..

thanks.

smrx8

iTrader: (1)

pretty good i hit 186 with a racing beat exhaust

dmp

what is a dynamic dyno?

philodox

nice baseline.. post a pic of the dyno sheet.. it's the only way you can get street credit with this crowd

Just another company that makes dyno's.. like mustang, dynametrics, dynojet, etc..

dmp

Philo - I didn't see if you answerd - sorry to topic jump;

Were the dyno numbers from your recent dyno 'correct'? If so, do you know what the correction factor was?

philodox

you should always use uncorrected results for a forced induction system. the reason being is with FI you create your own atmospheric conditions from pressurizing the air. make sense?

DreRX8

Yeah--the RX8 gets the girls to look ~$ $~

dmp

However, humidity, heat, etc, can change things - I think corrected values are still valid, having said that, I always use uncorrected results anyway...to me its more important what my car actually measures at, not what it'd measure in a 'perfect world'.

:D

philodox

True, but the thing is, the ambient air temp is not intake temp through the turbo and intercooler nor is the barometric pressure correct since the air is pressurized in the intake system. So the correction value the dyno program comes up with is going to be way off base compared to actual conditions inside the car which you can't really measure without a butt load of special equipment.

For a N/A car, corrected values are useful.. but for forced induction, they are very sketchy.

cretinx

Why are these cars dynoing so low? If they've got 238 hp like Mazda claims they should be putting down at least 200 hp stock.

philodox

hehe.. that issue has been kicked around in a bunch of threads. just search the forum and you'll probably find 15 or 20 of them

dmp

...only when comparing plots between cars in different areas, on dif dynos, etc. :D

rx8wannahave

We need pic's of the dyno run, and yes...the whp is around 175-185 range for the RX8 from what I have read.

zoom44

why do you think that?

Nemesis8

iTrader: (3)

Not bad at all - a high end claim - let's see the sheet man

Original RX8 247HP at the crank (Assume 20% loss = 197 RWHP)
Detunned US RX8 238HP at the crank (Assume 20% loss = 190 RWHP)
RX8Club Member RX8's make 210-220 HP at the crank (Assumine 20% loss = 168-176 RWHP)

Richard Paul

iTrader: (5)

Sorry your wrong Jon, corrected numbers are important no mater what. Blown engines are not exempt. We use these corrections so we can compare engines run in differnt conditions. If I run a test in Santa Monica and you run yours in Denver who has more power. I'd beat you hans down every time. You have to get a correction for altitude and temp and water vapor.

We all correct to the same standard. Now standards are different. We have SAE and Standard. All after market people use Std all Oem's use SAE.
The SAE uses ........................I don't remember. but I think it's 29.38 Hg and 70f.
Std is 29.92 and 60f. you can see the diff.

The factors seem to be accepted through out the industry. Except by some men in the RX 8 club.com. Well like I said "Just because it is written does not mean it is carved in stone"
Who knows there might be another Ricardo in our ranks.

dmp

Tis why I don't compare my car with any car but those run during my dyno sessions...Thus, I only read 'measured'.

blksf8

where's this guys sheet already?

rotarygod

I agree with that in terms of belt driven superchargers but not when it comes to exhaust driven turbos. Remember that a turbo will compensate to a point for altitude since it makes boost pressure as a reference to sea level pressure. Since a belt driven supercharger makes boost relative to ambient and not sea level, a correction is needed. Technically there should be some form of correction for an exhaust turbocharged engine too but the standard correction factors are more wrong than they are right. You and Jon are both right. It just depends on what type of supercharging you are using.

MazdaManiac

iTrader: (3)

^ Agree.

SAE corrected HP doesn't work for FI engines - turbo even more so.

gxsilver

i'll post it very soon, i'm pretty swamped at the moment.......

RX3+5

Could you post the raw data as well please?

Vince

leigh44

Please help me understand something. Mazda states 238hp. We see rx-8 club members all the time with 210-220 at the crank. Then we "assume" a 20% loss. Why dose this car only put 170-180 to the rear wheels? Don't get me wrong I love my car but crap we jump all over products that claim 5-15hp increases and spend $300.00-$1200.00 for them and we are down 58hp from the claimed crank hp to actual wheel hp. What is the reason for that big of a loss?!?!?!?!

dmp

Just a correction - I have yet to see ONE rx8club member dyno his engine at the crank. Automakers NEVER rate their cars at 'wheel HP'. We are likely down 10-20HP from what mazda rates...based on our WHEEL HP and guessing what acceptable drive-train losses should be.