EFIDynoTuning Forum

Thanks

Decipha, what do you recommend for a replacement PPRV? How/where can I get one?

A few questions:

How does a properly functioning PPRV function? My current understanding is that it is a valve that dumps pressure when it gets too high. Like a pressure relief valve in a hydraulic circuit would. A spring loaded bypass if you will.

Does a pprv function better than an external regulator near the tank and why?

Not trying to complicate anything just trying to be solution oriented and also gain some knowledge and understanding as well.

I’m on board with redoing a replacement pprv if I can source one and I would like to know more about how it benefits the tune.

Am I losing something by reducing pump prime time?

Please share

Apologies if my questioning is unclear

Wow! Thanks for the information!

Update: Currently have pulleys to run 18 lbs of peak boost now with the 2.65 tvs and the engine doesn’t “fall apart” with valve float that I thought might be happening at 20+ lbs. I clearly didn’t think enough about improving valve train components for that boost/power level. I will entertain the idea of springs and valves + guides if I run into additional issues as I was unaware. It seemed quite a few 03 cobra owners were getting away with more than it seemed in this sense…. I am wanting to hear or understand more wisdom on this topic please

Update: I set the throttle blade correctly. Then I had so make some changes to the mas air adders for a/c as fords values were bunk. I got it running more seamlessly during those compressor clutch engagements. I’m starting to understand how some stock functions were “calibrated” so inadequately.

I raised the values to lambda of 1 for tuning purposes but now that a have inefficient aftermarket high flow tiny cats I might just revert those values. Do you agree?

To update: I found the commanded slip table and reduced it and now the 3rd gear torque converter lockup is occurring to where it’s noticeable like a 4R100s lock up. Very nice!

Update: I went ahead and replaced the 1-2 shift servi and the springs (which were different than what was in there) per ford (snap on) catalog. So far it hasn’t acted up again. I reduced the speed at which 1-2 is commanded and now currently playing with pressure. Decipha’s recommendation considered I am at 30 psi and probably going to experiment with the next 10. Thanks everyone!

Update for fyi only: The factory marauder PPRV is integrated properly I believe. (Not something I wouldn’t have thought out and integrated well). And so, it just can’t handle the coyote pump imho. I went ahead and used a Holley filter regulator assembly set to 60 psi and plumbed a -8 return line to a bulkhead fitting at the sending unit hat. Then, reduced fuel pump prime time. I will call it success because it is now safe and pressure is stable. The Holley part wasn’t expensive looks clean and fits in the factory fuel filter bracket.

mbsvt1 wrote: ↑2023 Nov 27, 08:39

m-barans wrote: ↑2023 Nov 26, 21:56 Also forgot to note that mod max piston charts may not be organized quite well and is a best guess from what I had calculated. CPs are good pistons but a custom piston isn’t really more expensive. Might as well stroke the motor a touch while you are there.

My last build was with MMR 4.75 stroker kit for my 03 Cobra with a gen 3r 2.65 VMP

Sounds like a good build! My marauder engine is an iron block with Manley stock stroke crank, h-tuff Manley h beams and CPs with stainless rings and the 2.65 on top. I went a little heavier on the rotating assembly but she wraps out nicely.

But if I were to go N/A without the larger bores I would at least throw a coyote crank and rods in there. Inexpensive high quality mass production components, kind of like a Chevy thing! So that is a win for mod ford rodders… not to mention the weight savings