I'm having trouble to decide what injectors to go with. I talked to a good buddy of mine about it but was wondering what you guys think.

Here's my current setup:
99 GSR
DRAG III Turbo
V-AFC
OBD-I ecu

I'll be taking out my Walbro intank pump and replacing it with the inline pump that came with the DRAG kit. I've got a set of RC 370's sitting at my place right now. After speaking with my buddy, I've come to the realization that they may be too big. Do you think that a set of RC310's should be sufficient with my setup???

 

why are you taking out your walbro?

 

You can use either but you'll have to change the disk on your FMU accordingly. The 310's should be fine with a 6:1 or 8:1 disk. I take it you aren't boostin more than 10 lbs on stock internals.

 

You have an AFC. How can they be too big?

What else do you have as far as your fuel system?

 

Yea if you have an AFC, you could go as far as 440's and just trim them. IMO, go with the 370's and the Walbro, you should be fine at 8-9psi and proabably more.

 

Do you need a VAFC or SAFC to tune the FMU? I have an A/F ration gauge, does the FMU hav eany tuning capabilites or do I have to buy another piggy back to tune it?

 

you can buy disks to lower the pressure ratio, but its best to have the afc to fine tune it.

 

The only reason that I wanted to change from the Walbro intank pump to the DRAG inline pump, was from a number of threads that the Walbro would not be sufficient in handling the fuel demands of the DRAG kit. So should I stay with the intank or switch to the inline?

Also, another question about the injectors. Would I have any idling problems with the 370's as compared to the 310's?

 

Also another question, would I have to swith out the FMU disk? If so which one and where could I get it from?

 

I am not sure if I missed it, but what boost PSI are you shooting for? If you already have the 370s for your car, use them and fine tune them with the VAFC. DBman on this board has 440s (non RC injector) and is idling fine, even lowered his full boost fuel pressures with the VAFC mod. You can go to rceng.com and play with the injector calculators to find out how much pressure you'll need with the bigger injectors at full boost. It is always best to tune it on a dyno with a wideband, but not all of us do. Do the math and you'll be in the ballpark by lowering fuel through the VAFC for idling and off-boost settings, and check rc's calculators to find what max fuel pressures you'll need. And, about changing fuel pumps, there is a walbro that can handle (somewhat) high fuel pressures, check to see if you have it. We should never hit 100+psi fuel pressures, with a Bosch or walbro. HTH

 

you can have both pumps in there btw. botht he inline nad the intank.