Dont forget us ill be the first in line!!!

Regarding what??

I think he has several projects going on in parallel. I just received an e-mail from Paul regarding questions I had on the wheels his working on. It's nice to see that Paul actually answers the e-mails himself. Definitely looking forward to his three-piece wheel and potentially run a stagger setup (with proper springs and dampers of course.)

Looking at your handle you are probably looking for the supercharger. Haven't anything yet. For me, I am more interested in Paul's next tech article on engine performance.



Magic8

Oops double post!

I hope he will release additional info on his plans for suspension (ETA for the Stage 1) and exhaust (details) and intake (details). With a bunch of products coming to market it is getting difficult to wait -- but I am very intrigued by Yaw's offerings and have found his technical articles to be awesome.

Yep hes a smart guy.Im suppose to take delivery in the next to weeks,but i am really waiting for some dynos on mods of any sort.The 238 just aint gonna do it but i love the car.If he gets 250 to the wheels for under 4k im all over it.

First, I want to say I am in no way affiliated with Yaw. If this post is deleted it is rx8forums (and their members) loss.

I'm going to give you guys an update on Yaw's 3 piece wheels being designed for the 8. I've been exchanging e-mails with Paul and he seems like a great guy and he wants to see great things from the rx-8. The wheel will weigh 19.75 lbs (for the same size as stock). The stock wheel weighs 22.75 lbs., in case you didn't know. Cost: about $575.00 ea. Those of you who thought it would be only 100 bucks; sorry, that's just for the outer rim. Paul is trying to have them ready for Sevenstock. I asked him to post pictures/specs hoping those won't be deleted from the forum.

thanks for the inside info

Browsing through and saw my name. Thanks for the positive comments.

We've been busy with the engine project, and wheel designs mostly. Trying to do a bunch of things at once.

As much as I would like to be first to market with go fast goodies, that will not happen. This is a hard car to understand.

A bare motor on the dyno with aftermarket fuel injection is sensible enough, but the factory computer makes anything power related quite challenging.

I will probably get a big flame war started with this one, but this car will not dyno properly without the front wheels spinning. I spent an evening scouring the service manual, and there are pages of error codes caused by anything from a sensor reading being out of range, to a forced power reduction mode based on calculated catalytic converter core temperature.

This car is a rolling computer, and it is not thrilled with full throttle high rpm operation while sitting still.

The air fuel ratio will be rich, and the timing will be retarded. It's kind of like removing the speedometer cable from your TII. The car goes nasty rich and doesn't make any power.

It's so bad that I have dusted off my old in car dyno to use for development. It is a real pain to use compared to a chassis dyno, but at least the results will be accurate.

(I will probably have to amortise the cost of speeding tickets into the parts price!)

I don't want to be designing an intake system that increases power because it leans the mixture on the dyno, only to find that there is a power loss once the car is rolling and the air fuel ratio goes too lean.

The idea of running it on the engine dyno with the stock computer is not even an option.

As a result of all this complexity, and the cars bad attitude on a chassis dyno, I will need to outfit it with some data acquisition, and the in car dyno to make sense of the results.

As you can imagine, this may take a while. I want our parts to be the result of valid testing, and I need to know why the power increased or decreased as well as what the actual improvement is.

For those that are wondering, the next article will probably be about the renesis engine. I need to do a lot more testing before that can happen though, and the sponsor/customer of the supercharged engine project has asked that no specific information be made public. Kind of a bummer for me, but not uncommon in this type of situation.

It looks like we will make it to Sevenstock with the protoype wheels, and since the dyno cart is on wheels we will probably bring that along as well. If all goes well, we will have a set of prototype headers on the engine when we get there.

It is probably a goofy idea to bring an engine on a dyno cart to a show, but I think people will get a kick out of seeing it in person. You certainly can't see much of it in the car!

So...that's what we're up to. We will not be first to market, but when we do release a part it will be thoroughly tested and understood.

PY

Thanks Paul, great info.... makes me wonder how these quick to market intakes will actually perform.

Naysayers to RotaryNews be silenced!

Stupid question of the month: What is an in-car dyno, exactly? Are we talking about a G-Tech, or something more sophisticated?

jds

thanks yawpower

Well - this chap has impressed the hell out of me...

- Threw doubt at other people's offerings
- Tossed in a very plausible technical argument into the mix
- Stays true to his negotiated arrangements

If only he didn't have dud links on his website :( :( :(

Good stuff Mr Yaw!!!

At last , some credible possibilities as to the rx8 behaviour on dynos , instead of calculated speculation , well done to PAUL YAW .

Kudos Mr. Yaw !

Please continue to provide us the facts. I for one prefer to live in reality than speculation.

Originally posted by ranger4277
Thanks Paul, great info.... makes me wonder how these quick to market intakes will actually perform.

Naysayers to RotaryNews be silenced!

Thats what I was thinking. I will wait for whatever products you put out Mr. Yaw.

This may be my second Stupid Question of the Month, and in the same thread no less: Could this squirrelly behavior on the dyno be responsible for some of the dyno sheets that appear to show a larger power deficit then the Mazda-claimed 9 hp? Or is that wishful thinking? I'm no expert at reading these things, but the ones I've seen didn't SEEM to indicate a problem other than lower than expected power. From the descriptions of the problems in this thread, you would think people would have mentioned those issues before...they didn't sound all that subtle to me.

jds

From what i just read i think Paul is kinda stating that dynos for the 8 are inaccurate to a certain extent.Looks like bad news for aftermarket perf parts as far as speed of availibilty,but at least someone is on top of it.

After reading that i will most definitly wait for Yaw power parts.

The in car dyno is accelerometer based. It works much like the G-Tech, but with a few more calculations. Like the G-Tech, It measures the rate of acceleration with an accelerometer.

By doing a low speed roll down (Let the car coast in neutral from 10, to 5 miles per hour.) it determines the frictional loss. By doing a high speed roll down (From 60 to 50 mph.) it determines the aerodynamic drag.

Once the weight of the vehicle is known, it will calculate horsepower, and plot a graph.

To keep inertial losses to a reasonably low level, the run is normally done in high gear. (That's why I mentioned the speeding tickets.)

It has proven to be quite accurate, and quite cumbersome to use. Years ago it was all I could afford. Now we have the latest and greates in computerized engine dyno, and a chassis dyno on order, and I can't use either one!

(I can use the engine dyno, but only with aftermarket fuel injection.)

Some of you may remember that I supposed the RX-8 was programmed with some type of break in safety mode, and that was responsible for the rich air fuel ratios shown on the early dyno runs.

I guess I was wrong. The service manual details the way that the ECU monitors the engine, and other sensors, and how those inputs are processed. In the case of running on a chassis dyno, the computer will "investigate" the situation. And try to determine what is wrong. In other words, why is the driver asking for full throttle while I am sitting still?

For instance, DTC number P0500 States that under the following conditions, there is a vehicle speed sensor problem:

Car in gear
Engine speed more than 2,500 rpm
Load (Throttle Opening) more than 40%
In put signal reads less than 2.3 miles per hour.

It does not explain what actions will be taken once it thinks this problem exists.

In the ignition timing control section, it mentions one of the modes called Acceleration correction. It states: "Performs retard correction of ignition timing to prevent knocking at acceleration from a standstill."

There are other details about retarding timing to reduce power output, and richening the mixture in this situation to keep exhaust gas temps under control.

The manual has pages and pages of diagnostoc errors, protection modes, etc. Instead of wondering if there is some reason the car will not run properly on a chassis dyno, I am left wondering how in the hell could it run properly?

Someone asked the question, does this explain the low dyno numbers? My guess is ABSOLUTELY! Just last night I saw a dyno run posted to this forum which showed an air fuel ratio in the low 11"s! Of course it doesn't make any power! Add retarded ignition timing, and it makes wonder how it even makes 180 hp.

Right now, I have no idea how much power the RX-8 makes, but it is certainly better than the chassis dyno results show.

Unfortunately, the manual does not get too specific, and I don't know exactly what is happening to fuel and ignition maps. It is clear however that the mapping changes if the ECU thinks that the car is sitting still.

So for the time being, I still have more questions than answers. Until I have answers, I cannot design quality parts. We'll be working on it, and the suspension, which thankfully is not computer controlled.

PY

Yaw,

Wether gtechs are accurate or not is debatable, but they are still getting the same shape torque curves as the normal dynos. Here's one memebers gtech (i.e. in-car/wheels-moving results):

http://www.rx-8forum.com/showthread.php?s=&threadid=9186&highlight=gtech+pro+curve

http://www.rx-8forum.com/attachment.php?s=&postid=100614

Notice the downward sloping of the torque curve. It is down about 12% from 6K RPM to 8500 RPM. Very similar to other rear wheel dynos from other members:

http://www.rx-8forum.com/attachment.php?s=&postid=86764

Personally from driving the car I think there is just something "wrong" in the upper RPMs starting at 6000 RPM. I can feel the loss in acceleration (i.e. torque) and my mind says switch gears well before I should if the car was making all the top end power it is supposed to. And the run was done in 2nd gear so aerodynamics, if the gtech didn't compensate properly, would not be much of a factor.

None of these torque curves match the Mazda's published torque curve which was almost flat from 6K to 8.5K.

Whatever the problem is, I am sure you will find it, but I don't think has to do much with the stationary dyno being a factor.

-Mr. Wigggles

Mr. Wiggles,
How did my car end up in this thread?!? :p

I think that you were probably try to link one of my Gtech graphs.

Strange, I closed Internet Explorer and the graphs I linked still come up for me.

Are my graphs not coming up for anyone else?

Speed,

Yes, the graph you posted is very similar to the one I posted (or tried to post).

-Mr. Wigggles

Ps. as an FYI, my friend just got the Escort/Bel car dyno model and he is very happy with it. The results are much more consistant and the equations are much more accurate than his old Gtech. (He hasn't tested the new Gtech pro).

Originally posted by MrWigggles
Ps. as an FYI, my friend just got the Escort/Bel car dyno model and he is very happy with it. The results are much more consistant and the equations are much more accurate than his old Gtech. (He hasn't tested the new Gtech pro).

I was looking at the Escort performance meters before I bought my Gtech Pro. They looked like the would work well but at the time I couldn't find any reviews on them so I opted for the Gtech instead. If you get a chance you should try out your friend's Escort in your RX-8 and don't forget to post your results. :D

This does indeed look very promising.... There's another thread about trying to get all the sensor data out of the RX-8, and I'm wondering if anyone has tried using Autotap, or similar ODBII type interface to read info from the 8...

OverLOAD

I know this sounds like a suggestion that would require skills found only from one of the teams on the show "Junkyard Wars", but ...

Wouldn't it be possible to find a way to spin the front wheels? It would require a way to know approx. how fast the rear wheels are spinning as well as a way to spin the front tires at that speed without requiring any power from the car to do it. The "rig" would also have to allow the car to be firmly strapped into the dyno machine.

I have no idea what I'm suggesting since I've never even seen a chassis dyno!

Just a crazy thought. :)

how about a 4-wheel dyno? sounds even better?

maybe even a way to gear the rolling of the chassis dyno rear section with another section which keeps the front wheels spinning on the same section, since the car would normally have to spin the front wheels to accellerate.

Then you just need to find a way to bolt, strap, connect, somehow the car so that it doesn't go flying off the dyno... maybe like big roller wedges??

OverLOAD

I would be interesting if somebody tried dynoing the RX-8 with the front jacked up so the front wheels could spin. Then dyno the car with the front wheels still, and then hand spin the front tires as fast as they will go by hand and dyno again. If the computer is looking at the front wheel speed, it would probably show some difference.

Originally posted by yawpower


To keep inertial losses to a reasonably low level, the run is normally done in high gear. (That's why I mentioned the speeding tickets.)



in 6th you have no chance of reaching redline, in 5th there is a slim chance if conditions are perfect. Considering drag is proportional the square of the speed, I doubt you would want to do a pull in anything higher then 3rd gear.

Originally posted by BRealistic
I would be interesting if somebody tried dynoing the RX-8 with the front jacked up so the front wheels could spin. Then dyno the car with the front wheels still, and then hand spin the front tires as fast as they will go by hand and dyno again. If the computer is looking at the front wheel speed, it would probably show some difference.

I think it would be better to try to use a variable speed electric motor...

or better yet find the speed sensor, determine the electric output (usually 4-20milliamps DC), and use a signal generator to fake the speed.

However, there may be even more complicated programming which would compare intake pressure (which is related loosely to speed) to wheel speed. Cars are getting more complicated all the time.

Why not just send the signal from the rear tires to ecu input that normaly wouls be from the fronts? That way the computer thinks all 4 tires are spinning at the same rate. Shouldn't be too much harder than diconnecting the front sensor wire and running 2 wires from the rear sensor ecu input to the front speed sensor ecu input. That should work and you could undo it in about 10 mins and shouldn't have any ill effects on the car. Could be wrong but what do you think?

Originally posted by pr0ber


in 6th you have no chance of reaching redline, in 5th there is a slim chance if conditions are perfect. Considering drag is proportional the square of the speed, I doubt you would want to do a pull in anything higher then 3rd gear.

im with ya there, i've never hit redline in anything higher than 3rd...9500 in 4th, how fast is that anyway? ...way too fast for me =p

Originally posted by yawpower
The service manual details the way that the ECU monitors the engine, and other sensors, and how those inputs are processed. In the case of running on a chassis dyno, the computer will "investigate" the situation. And try to determine what is wrong. In other words, why is the driver asking for full throttle while I am sitting still?

For instance, DTC number P0500 States that under the following conditions, there is a vehicle speed sensor problem:

Car in gear
Engine speed more than 2,500 rpm
Load (Throttle Opening) more than 40%
In put signal reads less than 2.3 miles per hour.

It does not explain what actions will be taken once it thinks this problem exists.

In the ignition timing control section, it mentions one of the modes called Acceleration correction. It states: "Performs retard correction of ignition timing to prevent knocking at acceleration from a standstill."

If we assume that the car is performing poorly on the dyno due to this kind of intervention by the ECU, that still doesn't explain the poor performance and G-Tech results that at least some people have seen. Or the anecdotal reports of a lack of power at high revs.

I have one theory that might explain this: what if the cars are generating all sorts of ECU errors in normal operation, due to software bugs or problems with sensors? Lots of people seem to be seeing spurious Check Engine Lights so it looks like there are some problems in this area, and not all error codes would generate a CEL anyway (but they may still affect engine operation). This would also explain why some cars can actually achieve the stated performance - perhaps not all cars are affected and not all the time.

Originally posted by ChrisW

If we assume that the car is performing poorly on the dyno due to this kind of intervention by the ECU, that still doesn't explain the poor performance and G-Tech results

Yea, that IS the rub in all these arguments. Others, and my own GTECH Pro Competition simply show the WRHP just isn't there, save extrodinary power train losses. The other "MOST HOPEFUL" answer is we need to wait for SP1, or SP2, or SP? on the ECU at least! It's apparently one complicated piece of software that!

It seems highly likely the ECU WILL need further development, esp. if someone QUICKLY came up with a last minute ECU redo at port (who knows?) that has been done supposed to meet emmisions. If that is true is is highly likey that was not a well developed ECU effort, more like a FAIL-SAFE effort to get the cars out of port. Did someone say BUGS?

Bottom line, with:

1) a VERY HIGHLY complicated ECU-ENGINE dynamic
2) cutting edge protocol used in the ECU
3) few new-gen protocol readers
4) the tight-lipped philosophy of Mazda and its engineers
5) unknown DYNO testing possibilities

there is going to be an extended development effort required to get PROVEN results. Paul Yaw has said it best, and most dispassionately, and I'll be waiting to see what he comes up with, IF he comes up with something!

couldnt you do something rolling-road style, like the wind tunnels?
________
Pissing Panties (http://www.fucktube.com/categories/832/panties/videos/1)

Originally posted by Mazda Family
Why not just send the signal from the rear tires to ecu input that normaly wouls be from the fronts? That way the computer thinks all 4 tires are spinning at the same rate. Shouldn't be too much harder than diconnecting the front sensor wire and running 2 wires from the rear sensor ecu input to the front speed sensor ecu input. That should work and you could undo it in about 10 mins and shouldn't have any ill effects on the car. Could be wrong but what do you think?

Exactly what I was going to propose. Must be a breeze, no?

Originally posted by Spin9k


Yea, that IS the rub in all these arguments. Others, and my own GTECH Pro Competition simply show the WRHP just isn't there, save extrodinary power train losses. The other "MOST HOPEFUL" answer is we need to wait for SP1, or SP2, or SP? on the ECU at least! It's apparently one complicated piece of software that!

It seems highly likely the ECU WILL need further development, esp. if someone QUICKLY came up with a last minute ECU redo at port (who knows?) that has been done supposed to meet emmisions. If that is true is is highly likey that was not a well developed ECU effort, more like a FAIL-SAFE effort to get the cars out of port. Did someone say BUGS?

Bottom line, with:

1) a VERY HIGHLY complicated ECU-ENGINE dynamic
2) cutting edge protocol used in the ECU
3) few new-gen protocol readers
4) the tight-lipped philosophy of Mazda and its engineers
5) unknown DYNO testing possibilities

there is going to be an extended development effort required to get PROVEN results. Paul Yaw has said it best, and most dispassionately, and I'll be waiting to see what he comes up with, IF he comes up with something!

Boy, did I buy a car from Microsoft??...what am I going to do when the next Blaster Worm spreads? I had enough trouble cleaning up mail servers with th original!!:D

On a different note:
Spin9K, let's do a quantitative comparisson. Can you install your Gtech on another car with known Dyno figures? Don't change any parameters on the GTech from your run on the RX8. And compare the results. We don't care about drivetrain losses here. We would simply be comparing 2 different data sources and we could come up with a scaling model for it.

For example, if you have a car X that is Dynoing at 150RWHP; you then plug in the GTech to it and do a couple runs, and results in 170HP (assuming the GTech is not 100% accurate). Verify that the results are consistent. Then you move the GTech to the 8, run it a couple times with the exact same parameters. Let's say you get 180HP on the 8.

Then we can scale this as follows:

CarX
Dyno: 150RWHP
Gtech: 170HP

RX8
Gtech: 180HP
Dyno: 150*180/170 = 158RWHP

or even bettet, you will get the following coefficient: 180/170 = 1.058 which could be applied to the RX8's GTech HP curve to correct it and compare against the original dyno'd X car.

Alright, I made it complicated. Sorry.

bump. Anybody know what Mr. Yaw is up to these days?

If you're reading this yawpower, can you tell us things you've learned about the RENESIS in the past year?

Are there new products in the pipeline?

Check out his webpage (www.yawpower.com). He updated it not too long ago.

i noticed that too, however it doesnt really have updates on the RENESIS, on supercharger plans, or about new products

Heck, he hasn't even really updated the RX-8 wheel page either!

He must be really busy, as I should be and my schoolwork. :o

well y'know, he IS trying to build a competitive race car for the Speed GT thinger.

true, but he started that last year.

Any word? The latest posting on this thread seems to be a year, six months, and ten days old as I type this.

I used to check his site periodically, but after a while gave up. I haven't heard anything about them in regards to the RX-8 in a long time.

He mostly works on different types of rotary projects such as SCCA cars, rotary airplanes, boats, custom built motors for special applications, etc. He never really did get into the retail side of things like he intended to. As a result of this and the fact he stays so busy, he doesn't really update the website anymore. You might see an update from him every year or 2 but that's about it and even then it will only be on what project he has worked on lately.

what happeng to the renesis turbo race engine he was working on?

He was originally working on a Vortec supercharged Renesis for a Speedworld GT cup car but I think the project fell through. I don't think the car owner ended up going ahead with it.