Request: injector scaling and maps

Tuning discussion for all first generation Mazda RX-8 (2004-2008)
User avatar
wcs
Posts: 61
Joined: May 12th, 2021, 12:46 am

Re: Request: injector scaling and maps

Post by wcs »

Thanks for verifying your injector setup again, I just wanted to make sure I understood.

You might be able to make adjustments to the fueling and Tip-in to improve things in the lower rpms.
Perhaps even slight adjustments to the timing.
You can always play with the Throttle Control table to make it feel a little snappier.

You may need to consider tweaking the Cranking Injection Pulsewidth table if you continue to have trouble starting.
(I'm assuming the ignition is healthy?)

Unfortunately I have no hands on experience with the 4 port.
The VDI (Variable Dynamic Intake) on a 6 port opens at 7500 RPM.
This obviously maybe lower on the 4 port Auto due to the reduced RPM Limit.

However it also could by the SSV opening around 5200 RPM.
The SSV opens based on Engine Load, RPM and Throttle position inputs. Its typically accepted that it will open in the range between 3250-5500 rpm (on a 6 port).

Again sorry I've not seen what mapping tables are available on the 4 port but there should be a table for the VDI.
Is it set to 5200 rpm for the 4 ports (I'm genuinely curious) ?

Diagram of the 6 Port Intake and Control Positions (sorry I couldn't find one of the 4 port)
RX8_6portIntake_StreetRotary.jpg
RX8_6portIntake_StreetRotary.jpg (123.93 KiB) Viewed 1806 times
Hiddeninsight
Posts: 11
Joined: October 9th, 2021, 4:48 pm

Re: Request: injector scaling and maps

Post by Hiddeninsight »

I'll follow this with some info, but I have played with cranking injection pulse width and no matter what I set it to it shows 9ms while it's cranking warm, so I don't know if the logging doesn't work or the change in the tables. I see no noticeable difference in flooding or not when it's hot.

I don't have the best compression tester but it appears to be right around 100psi on all faces at 250ish rpm and higher as the rpm climbs. This is probably due to using Atkins solid corner seals on used irons which I've now seen a lot of people don't like doing because they take forever to wear in or never work perfect on anything other than new iorns.

Anyways from the maps.

Apv1 9000
Apv2 6100
Ssv 3000 below 0deg and 0 above
VDI 5750
Vfad 10000 since it doesn't have one

Edit: I changed the ssv to 3000 across the board and no noticeable difference. But I made a larger change in cranking pulse width in the hotter temp ranges since cold is 35ms and hot is as low as around 3 so I added 3ms to the warmer ranges and now it will actually start hot but long cranking time compared to cold, I might add more tomorrow and see what happens. Up to 115mi on it now.
User avatar
wcs
Posts: 61
Joined: May 12th, 2021, 12:46 am

Re: Request: injector scaling and maps

Post by wcs »

Thanks for the update.
I'm surprised you have APV tables available with a 4 port.
I've not seen any ECU flashing software that provides any real control over the SSV .. I wouldn't even bother trying to modify any of those tables.

Not trying to be mean, but in the 17 years I've been messing around with the RX8 I've never heard anyone say the 4 port automatic was fast. Never driving one I can't personally say.
But what you have right now maybe just what you have.
If you get what I'm saying.

I think its awesome that you have everything is up and running!
And if it runs on beast mode above 5200 rpm .... well you know what that means :)

Optionally if you wish to get a bit more hard core, the 4 port maybe a fun engine to boost.

https://www.rx8club.com/series-i-major- ... ad-266951/

EDIT: Which isn't as hard as you may think and I can definitely help you with the tuning.
:drive
Hiddeninsight
Posts: 11
Joined: October 9th, 2021, 4:48 pm

Re: Request: injector scaling and maps

Post by Hiddeninsight »

I've considered boosting it, and swapping to a better transmission, I'm just having a hard time justifying it in my head because the car is immaculate aside from my now messy engine bay.

It doesn't look hard to turbo at all though.

This is probably all it has speed wise, just need it to be a bit smoother in how it runs for me to be happy with it.
Post Reply