Do I need to change my IFR table if I installed a Walbro 255?


Thanks,
Jason

 

This will depend entirely on the pressure you see after vs. the pressure you see before. With a Walbro 342 I found the stock wiring to be very inadequate. The current demand from the Walbro will cause a voltage drop over the stock wiring...enough to show up as as a significant pressure drop at high loads. I did the calculations on the factory wiring guage and length and found them to match the voltage drop I saw back when I first installed the pump. I ended up running 10 guage directly to the pump to eliminate the voltage drop.

So to answer your question... maybe. It will depend on whether or not you see a difference in pressure before/after.

Tim

 

I find the best way to learn is to ask regardless of silly or not;
silly is if a person never asks, they will never know the answer.

You have to recompute the IFR table if either of the following changes:
a. fuel rail pressure; does you Walbro put out a different pressure than previous...?
b. injector rated flow/pressure (i.e. injector swap).

Edit: you'll have to measure your fuel rail pressure.

Regards

 

your fuel pressure will likely increase some (2psi or so) so you will probably need to adjust the IFR slightly (in the stickies, you can use the spreadsheet for IFR calculation... old PSI would be 58, old injector size would be whatever you have, then new pressure would be whatever you measure at the rail)

 

I have a 98 with stock injectors. I'm not sure what there rated at? They should be 28.5lb...not sure what there flow rating is?


So I get it right...

Injector Rated Fuel Pressure: ???

Your Fuel Rail Pressure: 58?

Injector Rated Flow Rate: 28.5?



Thanks,

 

Injector rated pressure would be 58, your fuel pressure would be whatever you measure it at at the rails, flow rate 28.5

It'll likely be a very minimal increase (if any at all , I know for sure my walbro 225 raised me up to 60psi since i Have a electric fuel pressure gauge)

 

Thanks...looks like my values went down from the stock setting. But...I have not measured pressure at the fuel rail...I guess its time to get a guage.

 

Fuel pressure gauge (screws onto end of fuel rail) is not expensive, goto Sears or parts store.

You'll have to search the forum or web to check the rated flow/pressure of your stock injectors.