Good to see the dyno data, Dave. Thanks for sharing that.

Now, I have a question for all the FI developers who may be watching this thread.

Dave, your dyno chart is another in a series of FI dyno charts that shows the benefit of FI falling quite dramatically beyond 7000rpm. (Please note, this is not a criticism of you or your set-up, just an observation about all for there has been some data published)

Why is this, I ask?

My theory is (and on which I would be grateful for comments) that it all has to do with an adverse interaction between the FI system (all systems I have seen) and the Renesis S-DAIS. Or perhaps (since induction has been changed fairly dramatically) with what the stock ECU says should happen because of the S-DAIS operation at 7250rpm, and the piggybacks aren't counter-compensating

As you know, in the NA Renesis, the S-DAIS has a major change point at 7250rpm, at which point, under WOT, the VFAD opens to allow additional fresh air. You feel this quite clearly on the road, just as you feel the the third set of injectors kick in (and your fuel economy kick out ) after 3750rpm

The Yamaguchi book talks about S-DAIS producing "supercharging effects" once the VFAD opens above 7250rpm, such that "the sonic speed of the incoming air....obtains maximum charge effects as high as 105%"

Are current FI systems negating or interfering with the S-DAIS engineering, and can a FI system be developed which co-exists with, or enhances it?

IMO, this might be partly answered by fitting FI to the 4 port (auto) model and seeing what the results are. My hunch is that the benefits of FI will be much more striking (please leave the remains of the auto tranny in the box ) and suggests the 06 model with the 6sp auto will be the ideal candidate for a stunning FI RX-8.

But...I could be completely wrong, and would be interested in people's views, especially about the interaction of FI and the S-DAIS

 

Hmmm....maybe I should post that elsewhere

 

No I think your reasoning is quite sound Timbo

In fact most FI in Japan are fitted in the 4 port engine. They are yet satisfy enough to put on all 6 port yet. Although I have seen TRUST and Fujita promoting it.

There will be a Hotversion DVD on the very topic. I hope I can get hold of it before the next VIC meet to show.

 

Thanks for your comments guys

Timbo you raise some interesting points . Thanx

I thought perhaps it might have been an issue with the Turbo itself ;ie. housing sizes

I hope to make the power curve a bit more linear at the top end
Ive seen the PTP Motorsports Turbo do a similar thing at the top , it just drops off
Between 7500-8 k rpm it drops 50 hp ! (in 500 rpms)
I'll endeavour to get to the bottom of it
Next dyno day is wednesday ..

Ciao

Dave

 

How about some torque figures ?
Every power curve i have seen drops after 7 k Rpm . PTP ,which has the largest Hp gain Drops off worse than this one . It may be a design thing with the Renisis
This engine does'nt need power gains at 8-9 k .It needs it lower
I feel happy that you dont need to redline it to make max power .
I think this power curve would be ideal if it came on a bit earlier and held it a bit longer up top
I have a feeling the torque curve would be better than rotormasters as you can see it makes big power gains at 3-5 k Rpm . The torque curve is a must to see here!
For a first go its a mighty achievement ,Im sure you know what you have to do
Its all about low to mid range power ,and I think your nearly there !

Carl

 

???? :

Hmmm... may be he does not track his car. The more rev the better Carl. It is all to do with gear ratio.

 

You Aussies and your extra "U".
Colour. Honour. Powour.

Something like that...

 

Umm, that's kind of what I was saying. I don't expect peak power at 9K either but I also don't want something that is peaky to drive.

 

With that much power and such deep gearing, it will seem "peaky" now matter how flat the torque curve is.
All 9k goes by quite quickly when you begin to mulitply the power output to such a degree.

 

Fair enough. I guess I'll have to drive some of these kits for myself to see how they feel.

 

Carl, that's exactly the point I was making in this post

All the FI modded cars just die at over 7250 rpm. It must be to do with the S-DAIS

 

Mine doesn't.
Even though my initial gains were modest (around 235 or so at the wheels at 4 PSI), my torque curve was flat and my power output was linear.
Now at 9 PSI and probably well over 260 HP, the delivery is approximately the same.
The G-Tech shows this. A real dydno run is in order, but probably a few months away.

 

I think we all in agree here ,in a round about sort of way ,I think Timbo you are maybe right about s-dias .Have to swing that idea over to MM ( Jeff )

Mazda maniac , how did you get the power curve linear ,is it to do with the phisicality of the turbo itself , the tuning etc. Its just that no-one else seems to know how
You have probably the best FI knowledge on this forum , this side of Tokyo Your comments are well respected
By THe Way , do you have any power/ torque figures of your kit
It would be interesting to see , I believe you and Ciao are using similar spec turbos .

Carl

 

I tried to find yours. My recollection is there was a technical glitch that prevented us seeing a plot of power vs rpm. However, if as you say, it runs linear above 7250rpm I'll have to rethink this

 

I'll get some torque figures when I get back on the Dyno Wednesday
The dump is finished and flows better.

Im sure you all know this was the first proper dyno pull and although I got some work to do to refine It Im sure with some trial and error We'll sort it out

Thanx

Ciao

Dave

 

All your U's are belong to us

and then there's the 's' vs 'z' thing....how did that happen?!

not to mention smaller gallons...and horsepower (scrambles back on topic)

 

Horsepower and torque are inextricably related to each other via RPM. Without getting into units etc, the basic formulae is Power = Torque X Revs.

So in general terms, the torque "curve" is constant (I.e horizontal), then the power curve will be a linear slope upwards. You generally see that with the NA RX-8, apart from the dips when the ports change, and the very top part. If the power stays "flat" as the RPM's increase, that means torque is dropping (which is inicative of what is happening on my posted pic).

All I am saying is you can pretty much derive the torque curve given the power curve.

Cheers,
Hymee.

 

I can recolect now at around 7000rpm the Air Fuel ratios spiked lean , and we had to richen it up there , but I dont think this has to do with the power drop off
Next dyno run will hopefully clear up a couple of things as I am testing a couple of theories ......wish me luck

Ciao

Dave

 

Good luck.

 

+1 (just wantted to see is i have a higher post count )

 

Well you should - you've been around a lot longer!

 

But I'm catchin' up fast - you're on 2.9 posts per day.

I seem to have cracked the 7 mark.

Hmm, who says I talk too much.

 

thirsty yet?

 

Ive got some footage that shows the engine bay appearing as stock
All engine bay covers fit in there stock positions
Even to the trained eye its hard to tell what lerks beneath
All covers come off and on in seconds as you will see

Here's the link http://www.ezzy-style.com.au/esmpix/...-eng-cover.mp4

Thanks heaps Ezz

Ciao

Dave

 

you know my email addy Dave...
dont be shy
it will get through as long as it is less than 10mb (attachment) per email

EDIT:
oops..... should've check my emails first hey.....
here is the link (quicktime player ver. 7 required)
http://www.ezzy-style.com.au/esmpix/...-eng-cover.mp4

EDIT#2
Dave (aka ciao) is actually in Sydney atm...... i have the official SPY shot to prove it......
the colour is right
it is turbo
and the number plate says CIAO

(apologies for the dodgy spy shot..... didnt think i had time to zoom in for a clearer shot )