Seeing as compression testers are difficult to come by where i live, and i know a guy with a dyno i decided to get the dyno'd as after a bit of reading this seems like a fairly decent way to see the condition of your rotary. The car got 213hp at the wheels. but according to the dyno man this figure is between 8-10hp + what it should be, as customers seem to prefer a slightly higher reading. i didnt put this up in the dyno thread as its not sae correct or whatever it is. im getting the graph mailed to me mid next week, so il post it up here. i do remember there being a slight dip in power at around 7k rpm but i think this may be something to do with the extra ports of the 231 opening up. Any way is this a fairly decent figure? after trolling through the dyno thread it seems as though anything above 200 seems to be acceptable.

 

Anything above 200 is good for a stock car.

 

It is difficult to make any statement on engine health based on this number without a proper frame of reference. Indeed the number itself seems to indicate good health, but to really make a statement would require that we understand what that dyno is reading relative to others. You mention that "according to the dyno man this figure is between 8-10hp + what it should be, as customers seem to prefer a slightly higher reading" - does this mean that typical, stock RX-8s are reading 8-10 hp higher than yours on that dyno?

 

no it just means that consistently the readings are that much hp higher than what the actual reading is. so say a brand new rx8 was getting 210whp it would read 218-220whp. if this is what you mean?

 

I have seen fairly new low mileage 8's dyno in the 190WHP range. Dyno results are kind of useless if you don't know what other 8's have put down under the same conditions on that dyno.

 

anything over 200 is actually pretty much impossible with a stock renesis.

175 is about normal if the dyno is reading right .

 

yeah you have a point if no other 8's have been dynoed on this dyno (as far as i know). i dont know if the higher octane fuel we have over here in europe would effect those dyno numbers though brettus. i was just using this as piece of mind, knowing that low compression motors seem to get alot lower numbers.

 

No - that wont make any difference.Seeing as the numbers are not SAE corrected , I'm guessing the test was done on a cold day . This could inflate the figure by up to 10%




A better way to analyse your dyno would be to compare the shape of the curve with others in the dyno thread .

 

its the UK. they "correct" everything to flywheel numbers. they never give a "wheel" number. this car, judging from past rolling road UK dynos, is probably in the normal 180-190 wheel numbers for a stock 8 in good working condition

 

I a greed with this!!!

 

I was about to say...

200 would be better, but with a stock engine of 175 is below average to me.

 

yeah it was a cold day about 1-3 celcius, no he did have a flywheel number but i wont get that till later on in the week when i have my next lecture. i do remember him saying specifically that this number was at the wheels, il have a look at the dyno thread though to compare figures. but i would still think 175hp is pretty low? these cars are supposed to be 227 from the factory right (at the crank) thats a 52hp loss.

 

The number from the factory is a lie. Just gotta deal with it. Only reason the numbers are so high is because the guy running the Dyno has it rigged and it's not SAE corrected. My guess is you're more in the 170-180 range.

My car made 174RWHP untuned and running pig rich with all my mods. Should be able to get to the 195 range after it gets tuned but that's about it. See VBGarage link in my sig for the list... kind of sad.

 

227 HP flywheel number is not a lie.

 

surely it wouldn't be a lie, what kind of kackhanded manufacturer lies about their figures

 

:facepalm:


neither is 270 give or take a few ...

.

 

Dyno numbers mean nothing unless you include conditions and what dyno you ran on. Even then it's iffy at best.

 

well they're talking stock. i nearly corrected Brettus on that earlier until i saw he specified stock

 

you guys are right, i spoke to a dyno pro yesterday who spent lots of time trying to get his dyno to correctly read the rx8's horsepower. but he said theyve all dynoed between 165-190 at the wheels, And that none that hes dynoed have ever made the 227 (flywheel) claimed by mazda. Its a shame really that they'd advertise it as that. But its still great car.

 

Not impossible, just not typical.
I've had more than a dozen specimens pop up over 200 with no modification or tuning.
As you might expect, those cars made minimal gains with tuning alone.

Not "normal", just typical. "Normal" would be about 190, which is where the majority of healthy, stock RX-8s have landed.

 

my reference is internally stock from TB to exhaust port exit

I don't know of anyone who has put said engines back to 100% OE trim. They always have at least pre-TB intake and post-port exhaust mods of some sort, and usually some tuning too.

 

A quick flick through the first 10 pages of the dyno thread

https://www.rx8club.com/series-i-tech-garage-22/dyno-results-compilation-77031/page8/

yielded theses results :

Stock : 165,176,177,175,190,173,160,147,178

Modified : 188,181,200,181,186,186,187,213,189,200,198,196,19 4,190,190,184

This includes the 'best' results from the first socal dyno day .

 

Yea but what Dyno? Some are extremely generous.

 

That was almost 5 years ago.
Many hundreds more cars have passed my way, so the sample size is several orders of magnitude larger.
Also, very few - if any - of those cars were stock, let alone "fresh".

 

last 10 pages of that thread :

Stock: 178,183,170,169,165

Modified : 186,181,183,160,167,218(ported),187,189,196,190,18 9,181,210(heavily modded),198,185