427 fueling issue

[cesar]

Got a 427 TT 5th gen in front of me, bosch 210 lb injectors.

I have done absolutely everything in the amount of time I had, and the car goes dead lean when the throttle is stabbed from a roll. The car also goes lean when it is being shifted into the next gear. I.E. perfect air fuel ratio, 15 psi, go to shift, make the gear change, stab throttle again, goes about 15% lean around 140 kpa, then transitions back to commanded afr. This seems to happen only after 4k rpm.



I have messed with simply modifying the transients, impact factor, ifr vs map table, transient gain mass, and just adding fuel on the VE.

The table on the tune im about to post, the fueling was all done in 4th gear.

When in 1st, 2nd, 3rd, whenever you hit it from a dead stop and as it progresses going into boost, it goes very lean around 15-20% lean until the afr stabilizes once the boost hits 15 psi. But, it doesn't do this in 4th, only in 1st, 2nd, 3rd.

Im convinced it is a transient issue as the heads are 265cc PRC ls3 heads. So the impact must be modified accordingly, but nothing i have tried has worked yet. Any help would be appreciated.


P.S. I have not applied the speed density air mode patch. Can this be an issue? I don't know what the patch does so I have not applied it.

and yes I have tried various injector data from ID, FIC, etc.

[5FDP]

Sorry I don't have the best help for the issue but you should not just max out the injector flow rate at 127lb/hr when your injectors are that large. You need to use the double stoich, half the IFR and IVT terms. That will allow you input the data at around 105lb/hr with the double stoich method.

[07GTS]

i do have some injector data for the bosch 210 lb when i was using them on 14psi boost they were quite good, yours will be better to scale with the larger IFR if u want the excel file just PM me with your email and ill send it thru, looks like doing the double stoich halve IFR as said above might be most of your issue but if u want to give it a go

[cesar]

ill pm you 07GTS, to compare the data.

@5FDP, the fuel is perfect when in steady state. The issue comes in when there is transients, which leads me to believe that it is an issue with transient tables. I have recently found out about Desoot, gna give that a try. As well as intake manifold volume.

I will report back.

[07GTS]

if your IFR is out like it is then steady state can be dialed in so it may seem to be ok but its not, enter the data i gave u and scale IFR 50% and do the stoich/IVT then the offset/min/short tables also and then adjust to suit and should be much better, also your stoich at the top ethanol is changed so just make that same as stock before u scale it if u use flex