The best way to find out if something is wrong with this dyno is to have a bone stock rx8 dyno at where you dynoed yours at. If he is hitting around 210 then you will know whats up.

I say get someone who has a dyno at about 200 should race him. At least then, he'll know his car is not faster... though he might still try to defend his HP numbers.

^ lol ok lets do it... I dynoed 201.5

Hmm Dyno Dynamic dyno's are usually quite good. Used by most mechanics here in Australia. Plus, l'm pretty sure my old car was dyno'd on a dynamic.

That figure is whacked though...

I'm not saying this dyno chart is or isn't accurate. However a completely stock Renesis has the ability to dyno 230 rwhp at the wheels but that's about it no matter what else you do short of forced induction.

Fred: I agree that the Renesis can probably squeeze out that horsepower but it woudl require quite a bit of work. Exhaust has to be redone, (and I don't mean just a catback) better spark, and extensive tuning would all be needed.

This RX-8 didn't have any of that done. (well, except for a Borla catback to make it sound pretty)

All signs point towards this dyno chart not being accurate, not with the mods this car has.

I'm talking about the potential of a completely factory internal stock Renesis with a stock intake manifold and even a paper air filter as that's what Speedsource has used to hit 230 rwhp. It does take a lightweight flywheel, a nice exhaust system, some high octane fuel, and some damn good tuning though. Performance is more than just bolt on parts. There's a deal of skill involved too.

The inconsistencies between so many Renesis engines on the dynos is quite simply due to the oil metering and it's inadequacies. Not all engines make the same compression due to slight warping issues with the apex seals. This is why the '09 models now have the 3rd center mounted oil injector and I'm willing to bet they would dyno more consistently and higher than the pre '09s as a result.

As I stated I'm not saying that this dyno is or is not accurate. I'm staying neutral on that although without any tuning you can probably tell which way I'm leaning. What I am pointing out is that the Renesis engine (assuming everything is working perfectly) has the ability do it with no special internal mods.

As a bit of an fyi: Mazdatrix built a Renesis that had peripheral intake ports but retained the side exhaust ports. They got around 230 at the wheels. My actual opinion on the motor is that the exhaust ports work great until about 230 rwhp n/a after which point they are too turbulent. I don't think the intake port sizes are an issue as they are huge. I feel the intake ports could flow enough for 300 hp n/a but the exhaust porting would have to be dealt with in order to do it whether through going back to an all peripheral setup or through some very difficult creative work on the stock ports.

Glad we're on the same page. :)

that's all very nice but the topic at hand is the dyno posted and for you to stay neutral on that has me scratching my head .....

Brettus:
read between the lines. ;)

What's got you scratching your head about my "neutral" comment Brettus? I know the topic is on a dyno run. I think I've been relevant as I've stated what the engine can do when everything is done properly which eclipses even this number and I've even quickly stated what it takes to get there as well as an explanation as to why some dyno higher than others. Look and see what parts on that list match or don't match the vehicle in question. My "neutral" stance is merely to avoid confrontation simply because it's not impossible. Probability is a different thing though. I have hinted my suspicion on it. The result nevertheless is posted for all to see and you know what they say about seeing. Don't question my contribution to the thread on the grounds that I won't just call bs on it. I have a few ideas but I'm not just going to arbitrarily say it's impossible. I do think it needs to be looked into more to base a firm conclusion though.

no it doesn't .
The key here is the difference in the two runs , the second run shows gains right through the rev range culminating in a peak never seen before with the mods done . No NA mods ever done have shown a result like that - never ever ever ever .
The peak is even flat and is at the wrong rpm suggesting the second run there was a fault with the engine like coils or something so with that fixed it would go up another 10-15 hp . Do you really believe that is possible ?
How you can even remotely suggest that it warrants a closer look is beyond me .

what numbers you see depend on what dyno you use, even within the same brand, but specifically how the measurements are made determine why some brands read higher/lower than others for the same car/mods

when I first made the major mods to mine with no tuning I made 201 hp on a Dynojet dyno in Texas

when Cobb did the initial tuning on mine it pulled 213 hp on a Mustang dyno at Cobb's SLC location

additional work by me and tuning Cobb brought it up to 220 hp on a Mustang dyno at Cobb's MMP location, this was after tuning, it read several numbers higher to start, but with mid-upper 14.x AFR readings, richening it up cost us a few hp/ft-lbs on the top end

they were all corrected to standard altitude/temperature

in *theory* a Dynojet dyno is reported to generate numbers approximately 20% higher than a Mustang dyno, the dynos that bolt to the wheel hubs in place of the drive wheels reportedly read higher still

So when somebody says they dynoed at xxx hp, the first thing I usually look for is what kind of dyno were they on ... the number by itself is about as meaningless as it gets, though as stated originally there will always be some variation even using the same brand/model at different locations so you can always question the validity of comparisons at different locations

Sure it warrants a closer look. I'll tell you exactly what assumption you are making in case you forgot. You are assuming that this shows an actual absolute power gain with nothing more than bolt on mods and you are assuming that this is all bogus as you've never seen it happen before. Keep in mind putting your faith in any dyno spitting out a true number is meaningless anyways as if they were accurate all dynos from different manufacturers would read the same. People only believe the one that gives them the highest reading yet no one definitively knows which is most accurate.

I see this chart differently and I take the numbers with a grain of salt. I see a first run that was done on a stock engine in June in Connecticut and another run that was done 8 months later after mods on a Connecticut day in a much colder month of February. We have no idea if these numbers are corrected or not. It doesn't say. There may or may not be a correction factor that we aren't seeing and it may apply to neither, one, or both of them. We just don't know. If these are non corrected numbers then you bet you could see a variance that wide. You are also discounting the mapping differences based on intake temperatures which is why you are doubting the validity based on the shape of the power curve yet this too is completely possible. You don't always have the same power curve in every temperature or load situation. That is one mistake with putting all of your faith in dyno numbers.

I actually don't care what his numbers are. To me it's worthless if not performed on a calibrated engine dyno. I look at a chassis dyno as being good for 2 things. One is tuning assuming you know how to use it. Full throttle runs are just a part of it. The other thing I see them as good for is comparisons but even then only when comparable conditions exist. That's the purpose of correction factors but I don't put too much faith in them because as I said your power curve may change based on intake air temperatures among other things and a correction factor won't change your powerband. It'll only scale it up or down linearly.

This dyno shows off 2 important things. One is that for best results, comparisons should be performed in as similar of air conditions as possible. High dollar race teams test engine dynos in air conditioned rooms for this very reason. They can control temperature and humidity of the tests regardless of outdoor conditions. You can not do that on a chassis dyno and a simple correction factor can't fix that.

The other important thing this chart shows is how uneducated so many people are when it comes to chassis dyno readings. If people don't provide a dyno chart, they get called out for it. When they do, they get called out for the results. It's a lose lose situation. Just because one car shows a dyno chart that read 180 hp and another done elsewhere or on a different day shows on that reads 200 hp doesn't mean one will necessarily be faster. They may actually have the same amount of power. How tightly are the straps holding the car down? How much air pressure is in the tires? You get the idea.

If you want to call bs on something, at least know what can affect the results before you do so. I may have my doubts about the true amount of power the engine is actually making but that could be affected by many things. I do see the shape of each power curve though and that's what gets my attention. I also don't really care how far apart in power the before and after runs were. It goes back to when they were performed.

Now if you're going to tell me that it doesn't at the very least deserve some more attention, give me a more thorough reason than I just gave for wanting to know more. I didn't say it did based on the power level. That's irrelevant anyways. I want to know more details about each run and how they relate to each other.

RG - wow ! I can't write that much in one sitting .
I am aware of the variances you speak of and did take that into account before I concluded that the dyno was BS .
To me the first base run was actually almost believable although suspect . The second run however is just so far off that none of the variables you mentioned could possibly cause that much of a discrepancy other than the dyno was wack . Look at the torque figure !!!!!!

How far out would it have to have been before you jumped off the fence and called BS ?

(waiting for the new dyno sheet with the coils)

wow talk about a fire storm i started lol, guys alot of good info on here and im truely taking it all in. Im not pissed at you guys for calling BS, i know very lil about the car and motor still learning by reading all these threads here. If you guys have questions about when i did it, yes the 2nd run was in a cold month but i also was driving around all morning athat day. what i was running for tire psi was 32 nitrogen filled at the time. I do all work on my car except tunning, that i have no clue what to do. I maintain it very well and run AMSoil in it. high test fuel. I will hit the dyno soon, and sorry i havent been on but i had to go play army for the weekend. The only thing i can think of is there may be somethnig i may have missed b/c i cant see it ie cluth and or fly wheel, but sence i have never had a lightened wheel in any car i have owned i cant tell you if it tacs up fast enough to have one.

Dyno will be soon

avanti . Have a read of this thread . This is what a race team could do after 1000's of hrs of testing . Food for thought .....



https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/223-rwhp-dynojet-na-4th-gear-178210/

i deff will tonight

I have it on good authority that the 09's make better and more consistent engine dyno power----your bet is a winner.