MonzaRacer
05-21-2017, 11:40 AM
This was in an old Corvette and they decided to install a crate motor. So this engine is roller cam, so I know I need the melonized gear. But this for the guys who have swapped tpi in before. I searched but got limited info. I am wondering if this is for 305 and I swapped the tpi to my other car and it was 350 can I allow for ci difference/injector size by simply upping fuel pressure temporarily. I do intend to swap injectors but to just get it running but time and funds may be limited. I have majority of parts. Just wondering about temp fix for smaller injectors.
battenheaded67cutlass
05-25-2017, 09:08 PM
Hello,
So, it sounds like you are trying to install a 305 tpi setup with the smaller 19lb injectors onto a 350?
The 350 TPI would have had 22lb injectors, so a very marginal difference.
You can make the 19lb injectors flow 22lbs by squeezing the FP regulator in a vice with an air line flowing at 60psi of regulated pressure hooked up to it while adjusting or adjusting it with a screw if yours is adjustable, you will need to add about 5lbs of static pressure for an increase of 1lb of flow approximately; 3lbs of additional flow would equal about 15psi additional pressure required.
Obviously, you can crack the FPR can and cause a leak when squeezing it. Don't do that, and don't start fires and blame me either. Check it with solvent for leaks and then hook it up if all good and check for fuel leaks. I had some super cheap but fun turbo dodges back in the day with crushed regulators to bump up the fuel available before hitting 100% duty cycle.
As a side note, most stock high pressure pumps will still be able to supply enough fuel at 60psi, but one of the in-tank high pressure Walbro 340's or Bosch 044 pumps will flow a lot more if you want to turn it up more.... Most of those larger body injectors will control seating just fine at 60psi..... some start acting funny at 80psi plus and just won't work that high.
You can set your flowing air pressure on your regulated air supply to 60psi and hook it up to the inlet side of the regulator. Set it up to squeeze it in the vice while hooked up to the regulated air supply; it will get quieter and shut off as you get close to 60psi of adjusted tension. You can turn up your flowing air regulator supply slightly and see that the fuel pressure regulator bypasses just over 60psi. This is a good start.
So, if you up the fuel pressure from 43.5psi to approximately 60psi static, you will have enough fuel flow for a mild 350 V8, giving it about 22lbs of flow.
Good luck