Injector question, upsizing on stock ecu

[Iantboyd]

I am currently running bp26/gtx stuff on my stock escort gt bp05 motor.

I am eventually going to put my gtr turbo on this engine, from my understanding the cfm capacity is greatly increased and so is the need for more fuel.

I am picking up a set of pnp rx7 460cc injectors and I am told that I can run these on my stock ecu.

How is that possible? I need some reasoning.

PS. When I install the GTR turbo the internals are getting upgraded and I will also have megasquirt available but I'd like to run mild boost on the stock ecu first.

[Turpro]

Seeing as the stock injectors size of the gtr is 440 is say the rx7 460 is fine to use. Gives you a little more room to turn up the boost as well.

[Iantboyd]

Yes, that is correct. What I mean is; how is the ecu able to accurately compensate? It doesn't know the inector cc's, right?

or is it just the fact that the same duty cycle is applied but since the injector is larger more fuel is delivered?

and if that is the case, would running the 460's with say a vj20 cause an overly rich scenario?

[concealer404]

You can run them on the GTR ECU, but i would NOT run them on the GTX ECU.

The ECU has no idea what injector is being used, so it's just pulse widths/duty cycles. ECU determines number/size of pulses, Injector size determines how much fuel is being delivered per pulse

460s on a GTR ECU would probably be just fine. A little rich (stock tune on 440s is a bit rich anyways), but not going to hurt anything.

[Iantboyd]

Thank you, Thats what I was looking for. From my initial searching it appeared as if people have been plugging 460's in with a gtx ecu and running the boost up. As stated I should have my megasquirt by then so I will just run that.

Thanks!

[bogaut]

Yeah you would need to run an s-afc or something to trick the ecu. But at that point, might as well go standalone

[concealer404]

Thank you, Thats what I was looking for. From my initial searching it appeared as if people have been plugging 460's in with a gtx ecu and running the boost up. As stated I should have my megasquirt by then so I will just run that.

Thanks!

They might be... to be honest, just as i started getting into the idea of boosting my Escort, i ended up going KL, and now i do own a turbo BP, but it's in a Miata using Hydra Nemesis, so... no idea what the stock ECU is really capable of. What i CAN tell you is that running 460s on a GTX ecu without an FMU or something is far from ideal.

Beyond that, it's all just general knowledge.

[CODY004WD]

I ran E85 On a bp26 ecu with 460cc injectors and 10psi from the Eaton M62. I had an a-code VAF from a TurboII RX7, and an aeromotive AFPR. This combination allowed me to fine tune with the VAF and the AFPR. Finally with enough fiddling I was able to get a very stable tune, and eventually pushed the Base timing to 18* with no signs of detonation. The wideband, A-code, and an AFPR were my main tools to get it working, but I don't know, maybe you'd need an safc to make it possible on pump gas.

[bomdoutscort]

I would ask Jinx. He ran 460 injectors with a t3 turbo on a bp26 ecu. He did have a safc but he said it was disconnected for his dyno pull. Also BoostedEscort also was running 550 cc injectors with a gtr ecu on his holset build. He said during the dyno the afrs were solid. So i'd start there.

[Boosted Escort]

^ my injectors are 460cc rx7 injectors with a gtr ecu. I am also running the egt fuel pressure regulator. I used to have a set of 550s but i sold them before i got to use them.

If you are wanting to run the gtx ecu with 460cc injectors you are going to have to tune the vaf with a wideband. You will need to trick the ecu by tighting the vaf because the gtx ecu is mapped for 330cc injectors. This will allow you to run the 460cc injectors on a gtx ecu your idle probably wont be smooth but it will alow for safe air fuel ratio in boost. I would go with the A code vaf from the turbo rx7 it is better than the B code vaf.

[concealer404]

If he's going megasquirt in the future anyways, i wouldn't mess with the VAF. The "VAF" trick also messes with your timing.

[bomdoutscort]

I stand corrected.

[concealer404]

I know people have done it successfully, but my main issue with it is in the very basis of how it works.

You're "tricking" the VAF into seeing less air to make it pull back how much fuel it dumps out of the now larger injectors.

Less air = less load. Less load = more timing. More timing + WOT/Boost = boom.

[atomicEGT]

get a GTR ecu
add 460s
run ALL the boost
???
profit.

[FE3-323]

How is that possible? I need some reasoning.

"Mazda witchcraft"

GTX ecu can fully support tested & tuned. 330cc(mx6/probe-vj11)/360cc(GTX)/460cc(rx7)/550cc(T2)
tuning with the vaf is all that is required.
given. running 100cc+ on the factory turbo isn't recommended unless your using E85 or sorts.
460's on a VJ11/VJ20 will run pig rich @ "IDLE" regardless of vaf tuning.