california style

As some may have realised im a tuning and mod nub.

I have seen many interesting and informative threads here and am following supercharger and engine manager news avidly. However i would like some help from the esteemed community here.

1. Dyno stuff. I see a lot of "show me the numbers" calls.... but i have no idea what the numbers mean!!!

Can someone explain the stock numbers, torque, HP, Wheel HP (is that what people are on about?) and what the diference is between HP and wheel HP and how u measure it.

A post with all the Hi Power stock numbers for all figures would be pretty handy for comparisons.....

Also, on another subject, can some1 clear up the basic diferences between the Hymee, Petit and Axial Flow SC's?

california style

no one can explain the numbers? has everyone been bluffing til now?

Red Devil

No one is bluffing anything. You probably don't have a response because what you ask for can be found on Pettit's website and in their thread, or for that matter Hymee's thread and website and the Axial Flow website and thread. The threads are long, but information is already available.

As for the difference and relations between torque and hp, this is a good start...
http://www.yawpower.com/tqvshp.html

california style

thanks for responding Red, but i have been to Hymees site and the pettit one, and see no base HP figures for a stock Hi Power RX8. esp as people keep going on about HP to Wheels....
Hymees site has a dyno thing for the stock vs his exhaust, but i cant make head or tail of it.

I know the stock has 231 HP (officially but is this right? does the constant remapping from Mazda change this at all?) but what is it to the wheels etc? Also i have no idea about stock torque numbers

I know the diference between torque and HP tho 8)

Richard Paul

iTrader: (5)

As near as we know from independent tests the stock HP at the flywheel is 215 +/- 4. The rear wheel HP is 175 +/- 5. That's the truth of it, don't cry in your beer.
The HP outputs of the various superchargsrs is still up in the air as there are not any production units in customers hands yet. Wait a few months and save up your money.

Hymee

iTrader: (1)

California Style,

I think RD meant read the threads, not my site. I have not publlished any info on my blower on my web site yet. Not long now though...


https://www.rx8club.com/showthread.p...24#post1045724

Cheers,
Hymee.

mikeschaefer

Flywheel Horsepower (also known as just "Horsepower") is what car manufacturers list as the car's horsepower rating. It is measured at the flywheel (before the transmission). It basically tells you how much power the engine can make.

Wheel Horsepower is measured at the driving wheels and will always be lower because power is lost through the drivetrain.



It's important to keep in mind that most of the people that dyno their cars are measuring their Wheel Horsepower. So if you see someone getting 250 WHP (Wheel HP) you might be thinking, "Well the car came with 238HP... so that's not much gain, only 12HP?!?!" In all actuality 250 WHP is a considerable gain for our cars.

So take what Richard Paul said: We only get about 215 flywheel horsepower (not 238 like mazda says) and about 175 Wheel HP.

If someone dynos and gets 250WHP they probably gained around 75 HP. Much better than 12 eh?

Hymee

iTrader: (1)

Nice explanation mike. Well done.

Cheers,
Hymee.

california style

thats great fellahs... exactly what i was looking for.....thanks a lot

Now any ideas about 'real' stock torque figures as well?

PS Can i cry to Mazda about my 'missing' 15 hp? Did they lose it on route to the UK?

pcimino

Has Mazda ever explained how they got the 238 HP number? I remember when the RX-8 first came out it was officially "250". Then they backed off that and came out with "238", and offered all sorts of deals to customers who already bought the 8, to avoid lawsuits, including a buyback offer.

But so far, I've never read that anyone dynoed over 220 with a stock engine. Admittedly, that is getting the wheel HP and calculating the engine HP. No one seems to think the transmission on the 8 eats up 25%+ HP. So how did Mazda come up with 238?

Glyphon

mazda lists torque at 159ft/lbs (6MT), and i seem to recall seeing wheel torque from dyno sheets at around 125-135ft/lbs range.

and no, you can't go crying to mazda about "missing" power.