What all would it take to run 680cc injectors?

[blackgamer16]

I ask because am about to source me a vpc with a 550cc chip and if i remember correctly i read a member running the same setup as i am about to do. I just really wanna know on the guys that have ran 680ccs. What did you use to control your a/f and if you think a vpc is the good/great/bad choice with of course a afc of some sort. I understand that some mk3 owners gone standalone but I really don't feel the need for that right now.

Money is not an option but i do live in oklahoma and the closest aem tuner be like houston or something and that be a b*tch to get tuned.

My setup:
rebuild stock bottom end (clevitte(sp) bearings the works, you know)
2.0mm Titan MHG
Port n polish head + 3 angle valve job

And waiting on puttin on Ron's FFIM, AiResearch t04e 60 trim, Powerhouse Exh. Mani, HKS Wastegate

And IC either be HPF 3 row or an ebay cooler.

My goals are 450-500 street.

Just give me any info you can think of. I know there is tons over the 550ccs and i just hope we can get a good thread about 680cc injectors.

Thanks in Advance
Blackgamer

Ps. And yes I've searched, i only get very brief info on running these size injectors.

 

[Turbo. Targa. Life.]

Funny, I actually got on here to post nearly an identical question. Hopefully you won't consider this as hijacking.

Planned setup:
RC 680cc injectors
Dual Walbro 255's (Refuse to use an a1000--too noisy)
SAFCII
Aeromotive AFPR

Would this setup require a bigger fuel rail and/or lines?

 

[supra90turbo]

Stock fuel rail is proven to provide enough fuel for at least 800rwhp

 

[empera]

hmm could i run vpc with 550chip and 680cc injectors?

 

[ToyoHabu]

The problem with large injectors comes in the low rpm range where control can be a problematic here is an excellent write up on the megasquirt site injectors

 

[dbsupra90]

what i have found is 550cc inj work better on the 440cc chip and the 680cc inj work better w/ the 550cc chip.

aside from that, the biggest tuning aid will be an adjustable fuel press regulator. changing the base fuel pressure will allow you to control the flow from the injectors. you can essentially make the injectors flow more or less than their rated size. be careful tho, if you change it too drastic you can effect the spray pattern.

for what its worth, between my friends and myself we have ran 680cc injectors with lex afm/afc, maft/afc, vpc/afc, and maftpro- all with an afpr as well. all ran very smooth and very tuneable.

 

[blackgamer16]

good info dbsupra90

you have any numbers you where putting down and around where was your A/F at?

 

[WeDgE]

Why bother with 680s if you're only using a 60trim T04E?

 

[supramike7m]

ya arent 550's enough for 450 - 500?

 

[Turbo. Targa. Life.]

Future planning my friends, future planning

I have another motor in the works with a higher compression ratio. Shooting for 400-450 at ~10psi, up it to ~20psi for 5-600 It shall be a monster!

So in essence, why buy injectors twice, when I know of a source where I can get 680's cheaper than most places 550's? RC of course. Turn the duty cycle down to 70-75% and be done!

 

[supramike7m]

damn, 450 at 10psi!

 

[Justin]

what i have found is 550cc inj work better on the 440cc chip and the 680cc inj work better w/ the 550cc chip.

I second that about the 550s working better with the 440 chip... couldn't commend on the 680's though

 

[blackgamer16]

Why bother with 680s if you're only using a 60trim T04E?

the 60trim to4E is my first setup... And for sure won't be my last. If i was just going to keep the to4e i'll be satisfied with 550s. And no need for making this thread.

Back on topic- I guess i'll just give it a shot and see where it goes. If i remember right i think the mk4 guys do the same thing but theres chip maxes out at 720cc and they've gone well beyond that injector size for sure. Anyways its worth a shot! Thanks for the replies guys

 

[peter551984]

OK that sounds nice but I want the same goals, 550hp at wheels in streets, but in future plans 750 or 950cc... but I have a question can I use 680cc with stock fuel rail, dula walbros, fuel regulator, lexus maf and an Apexi SAFII?

 

[gotsomegetsome]

AFPR is necessary? So the stock setup simply wont take it huh