Today, I was able to run over 100% on the MAF fuel table. When I did this I had a wicked fuel cut or something. It was real similar to when the vacuum line blows off the regulator. I noticed that my AFR's try to go to the high 9's-low 10's in that region. So basically, what happens when the injectors hit 100% or when the MAF goes over 100%?

Is it ok to add a 105% row on the MAF fuel table?

 

I'm assuming you have a Walbroor other fuel pump. I don't know the specific answer, but it obviously sounds like you need bigger injectors.

From a layman, my question would be how can injectors function at over 100% duty cycle?

 

Injectors can't, but the MAF may be able too. What I want to know is what happens if one or the other becomes 100%.

 

Going static on the injectors wont induce any strange fuel cut. Have you measured IDC with PWM0in? Also, the 100% point on the load axis is pretty much arbitrary. We just picked a max frequency and assigned that to 100%. We could rescale MAF quite easily with a big-turbo specific firmware update. I'll talk to the software guys tonight...

shiv

 

No. I am not exactly sure how to do that either. I assume I just splice into the injector signal, but what port on the XEDE do I run the signal too?

 

I tried adding a 105% row, but the XEDE overides it to a 128% row. Any values I put in it gets scrambled and new numbers will appear in the zero row.

 

Adding the 128% row seems to have fixed the problem. Hopefully, when I turn up the boost another 4 psi this problem doesn't come back.

Shiv, have you ever seen any problems w/ the traces on the MAF map? Mine seem to be skipping 5000-5500rpm cells which is where I am stupid rich (low 10's). Everything above is 11.5-12.0 and at 4500 its 11.5.

 

I found the limits to the injectors yesterday. I kept adding fuel (up to positive +8.0) and nothing would move the AFR's lower then 12.1-12.3 at 7000rpm at 28psi. I am ordering some 880cc injectors and sending my ECU in for a reflash Monday.

 

I assume you aren't on the stock turbo....BTW....I may be interested in your 680s if the price is right.

I have been hanging out in motorsports forum. Most of those fellas recommend bigger than stock injectors for road racing.

After you get the larger injectors and XedeFlash, do you still use the same XEDE maps?

 

My injectors are for sale in the sale section. I don't think injectors need to be upgrade until the turbo is upgraded. Even w/ cams you can run the stock injectors to an AFR into the low 10's.

If you do buy injectors you have to get them scaled w/ the XEDEflash and you won't be able to use the base maps. They'll need to be adjusted for the added fuel.

 

Roger that....thanks.

 

I don't know what's going on but its starting to irritate me. I keep getting a stutter at 5000rpm and I can't get rid of it. It's running crazy rich right there, but I can't adjust it because it isn't hitting any cells in that column. Actually, I am only hitting 2 columns after 5000rpm. I'm pretty sure this is why my positive fuel adjustment w/ the smaller injectors have had no effect in the 6500-8000rpm range. Now, with my big injectors I am going to have some low AFR problems in those regions and probably an extremely rich spot at 5000rpm.

OK Vishnu, I am going to need your help on this since I have your dyno day coming up next weekend and I would like to attend w/ a functional car.