RX8 with Grams 1000CC injectors

Tuning discussion for all first generation Mazda RX-8 (2004-2008)
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Torchwood007
Posts: 6
Joined: November 3rd, 2021, 9:12 am

RX8 with Grams 1000CC injectors

Post by Torchwood007 »

Hi

Can anyone help please as I am losing the will to live here !!

I have 1000CC Grams injectors (x4) to be put in place of the standard YELLOW injectors in my 231BHP RX8 Series 1 which has had a full complete rebuild to the engine

I have the Latency table direct from grams but cannot figure out how to convert it for use with the VERSATUNE software which uses the same mapping tech as most tuning software

Would you be able to assist me in getting my Versatune information correct for these injectors ?

Thanks

Latency table is here : https://gramsperformance.com/g2-1000-1000.html
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wcs
Posts: 61
Joined: May 12th, 2021, 12:46 am

Re: RX8 with Grams 1000CC injectors

Post by wcs »

Omg don't lose the will to live!
:thumbup
I have to ask why haven't you hired a Tuner to do this for you?
You've obviously laid out some big dollars just go the last mile.

So that aside.
I've only ever remapped known latency tables from other RX8 injector sizes to my tunes.
(I've spent a few trips around the block swapping out various size injectors).

Maybe someone can step in a validate my assumptions or add insight.
(or tell me I'm an idiot)

I have wondered about the table value units and the X axis sensor input.

First I believe the top BARO PSI values are measured using the Barometer located by the Secondary Air Pump.
Making those values ambient atmospheric PSI readings.

Second, the Table Values in Milliseconds I believe is incorrect and should be Microseconds.
The latency at 14.93 psi and 14 volts would be 610 milliseconds or over half a second.
VT_LatencyTableAxisDefinitions.jpg
VT_LatencyTableAxisDefinitions.jpg (204.26 KiB) Viewed 2391 times
With that out of the way I would make the assumption that the injectors were tested at sea level pressure or 14.7 psi.
The RX8 Series 1 should have 60 PSI of Fuel Pressure.

First would then modify the X and Y axis to match the know parameters for the Grams Latency table.
If you've never done this I've briefly pointed out the steps
VT_ModifyXandYAxis.jpg
VT_ModifyXandYAxis.jpg (386.24 KiB) Viewed 2391 times
Then enter the table value from the Grams latency table to our update VT Latency table.
VT_GramsLatencyValues.jpg
VT_GramsLatencyValues.jpg (161.73 KiB) Viewed 2391 times
Then its a matter of using the interpolation tool to make it look something like this:
Do NOT use this latency map!!!!!
I just slammed this together to show you how you could possible create your own.
Assuming my assuming above is correct.
VT_Grams1000ccLatencyTEST.jpg
VT_Grams1000ccLatencyTEST.jpg (162.56 KiB) Viewed 2391 times

If someone that does actually have experience doing this and would take the time to skool me (us), Please I'm all ears and have a thick skin.
Enlighten us please.
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wcs
Posts: 61
Joined: May 12th, 2021, 12:46 am

Re: RX8 with Grams 1000CC injectors

Post by wcs »

It doesn't look like the OP is around anymore.
But I stumbled across this process to build a latency table for Injectors on the RX8 so I thought I would post it here for anyone else that may require latency assistance.
It might be tricky to complete the table without using a Load bearing dyno.
I've never tried this process so you've been warned.
The source is from the Cobb Access Tuner Race Helpfile for the RX8

"Most fuel injector manufacturers will be able to provide you with this latency data and the voltage they are referenced at.
Use that as a starting point and modify from there. Don't be afraid if your final values differ from what the
manufacturer provided. To tune this table, we suggest that you first establish a good Injector Size value.
One way to find the correct latency (or at least the latency that works best with the injector drivers
in the ECU and your particular injectors) is to have your fuel system running stock fuel pressure and have
the stock intake system installed then;
1st - set the proper size value for the secondary and auxiliary injectors you are using based off the injector
set size calculation.
2nd - start the engine and let the car warm up to temperature (coolant temperature between 180-195 F and
intake air temperature +/- 15 degrees F of ambient temperature) then re-set the ECU so your fuel trims
start at zero.
3rd - start the vehicle again and watch the SUM of your fuel trims, A/F Trim Immediate + LTFT
If you see that the SUM of your fuel trims (STFT + LTFT) is positive then add injector latency until you
see the SUM of your fuel trims come closer to zero. If you see that the SUM of your fuel trims is negative
then reduce injector latency until you see the SUM of your fuel trims come closer to zero. You will have
to test this throughout the operating range of the engine...the entire MAF curve. Try to avoid sudden
throttle movements during this process, you want to avoid seeing any corrections based on the tip-in
enrichment table settings.
This is part of a calibration process that should be able to get you close to the ideal settings
necessary to properly control your secondary and auxiliary fuel injector sets. Please take into account that
you will most likely have to fine tune the MAF calibration table as the final step. This will be necessary to
match the characteristics of the new"
Walle
Posts: 51
Joined: August 29th, 2021, 7:27 pm

Re: RX8 with Grams 1000CC injectors

Post by Walle »

very nice writeup :burnrubber
Torchwood007
Posts: 6
Joined: November 3rd, 2021, 9:12 am

Re: RX8 with Grams 1000CC injectors

Post by Torchwood007 »

Thanks to WCS for the info

I have attached the detail from the Gramms website for these specific injectors - If someone can send me a screenshot of what I need to change where so that the map corresponds to the values from the Data provided by Gramms I will be very grateful indeed - You are right - I did spend a lot of bucks on these and want to get them in the car and working correctly

Can someone help please as they are just sitting on a shelf gathering dust at the moment

Thanks

David
Attachments
Data Table
Data Table
IMG_1879 small.jpg (36.52 KiB) Viewed 2108 times
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