Need recommendation on injector size

[toomanymodz]

I'm on the fence about this and hope others can chime in. I am slowly getting together a new combo and I'm not certain if I'll need new injectors or not. The new engine is a Weber stroker engine (109 block, std bore, 3.625 stroke). Cam is a billet roller 218/212. Heads are Champion GN1's with the full CNC port option. Intake is Champion with full porting as well. 70mm throttle body. I'm not 100% certain where the shift points will end up, but I'm guessing around 6,000 - 6200 RPM. My current turbo is a PTE-51.

I currently have 60# injectors, which may or may not work on this new combo. My current engine shifts at 5300 RPM and I'm seeing 78% duty cycle. My current engine sports an unopened short block with stock cam. The heads were ported with new springs. I usually run 19 to 20 psi on 93 octane (no alky).

Do I even waste my time with 60# injectors with the new engine? I'm thinking that I may quickly run out of injector at 6000+ RPMS. I'd hate to order a chip and then quickly find out that they're not big enough.

I see 72# or even 80# injectors available. Should I go that route or stick with my 60's?

 

[Major Nutz]

You're ok with the 60's. If you had the extra cash you could move up to the 80's but its your choice.
Mike

 

[just plain john]

It's no big deal to change injectors, so if it were me I'd keep the 60's for the time being. After a couple of runs you'll be able to see what the duty cycle is doing and act accordingly. Of course, your budget is bigger than mine (they don't give those stroker Webers away do they?)

 

[forcefed3.8's]

The 60's will go mid to low 10's. Your turbo wont.

 

[toomanymodz]

Thanks for the replies. I'll keep the 60s then. Yeah, the turbo will have to be changed in the future. Money is tight right now. I'll probably go with a 6265 later this year.

 

[bison]

If you go with more turbo and run it to even 75% of its potential your current injectors won't cut it.

 

[toomanymodz]

I hear ya Bison. The cash is tight right now, so i may just run the 60's with the PTE-51 for now. Hopefully it can manage ok at moderate boost levels (16 to 18 psi).

Later this year I will upgrade the turbo, injectors and fuel pump at the same time. I'm only running a single Walbro right now. There is that Supra pump and a few other ones now available (Racetronix has one too) but that's a whole different topic that I'll have to research later this year.

 

[49-blues]

Sent you a PM.

 

[jasjamz]

You have the hard part out of the way...the engine. The 60s should support 720FWHP or so. I would just keep it mild and buy the needed fuel part when the money is there. At least it's driveable and should be able to make easy 11 second passes.