Adjustable Fuel Pressure Regulator

[boxyjeep]

Thought you guys would appreciate a sneak peak of a kit we are working on for an adjustable fuel pressure regulator for Renix 4.0L.  Inspired by this thread and the fact that the Hesco unit is trash, we came up with our own solution.

 

Will have a video up soon with an overview of what's required, but this has resulted in my 4.6L Renix stroker running really well, without the need for an adjustable MAP sensor (which is actually a pretty poor solution).

 

 

Overview video (please subscribe!):  

 

 

[Eagle_SX4]

That is really cool. I kept my Renix fuel rail when I swapped in a 98+ manifold. If I ever have fuel pressure issues. This will be the solution.

[boxyjeep]

Just now, Eagle_SX4 said:

That is really cool. I kept my Renix fuel rail when I swapped in a 98+ manifold. If I ever have fuel pressure issues. This will be the solution.

 

How'd you pull that off?  From my understanding the fuel rail bolt holes are in different locations from HO to Renix...

[Eagle_SX4]

Just now, boxyjeep said:

 

How'd you pull that off?  From my understanding the fuel rail bolt holes are in different locations from HO to Renix...

Yes the bolt holes don't line up so I cut the center 2 feet off and welded some 90 degree brackets on them and it works very well.

[boxyjeep]

Just now, Eagle_SX4 said:

Yes the bolt holes don't line up so I cut the center 2 feet off and welded some 90 degree brackets on them and it works very well.

 

Nice!  I'm impressed.  

[Eagle_SX4]

I was going to use a '93 fuel rail but I didn't want to make new fuel lines. The Renix fuel rail also runs cooler due the full circulation of fuel and shouldn't vapor lock as easily.

[garyweb3]

Anything for a Renix 2.5?

[boxyjeep]

2 hours ago, garyweb3 said:

Anything for a Renix 2.5?

 

DM me some pics and we might be able to work something out!

[TheNerfsmith]

Are there advantages to the Renix rail? I didn’t know that the systems were that different. 

[boxyjeep]

11 minutes ago, TheNerfsmith said:

Are there advantages to the Renix rail? I didn’t know that the systems were that different. 

No, lol.  But it’s the only rail that bolts to the Renix intake manifold.  If you’re going to swap to a HO rail, it requires a HO intake, throttle body, ditch EGR, etc, then this kit is unnecessary.  But if you want to keep it somewhat original and gain some adjustability, this is a good option.

[garyweb3]

This diagram is from the TBI manual. It looks like the factory had some sort of fitting to set fuel pressure. I don't know if this helps or would you like an actual picture of my throttle body?

[boxyjeep]

20 hours ago, garyweb3 said:

This diagram is from the TBI manual. It looks like the factory had some sort of fitting to set fuel pressure. I don't know if this helps or would you like an actual picture of my throttle body?

 

Unfortunately I don't think kit is going to easily adapt with the 2.5L TBI engine.

[garyweb3]

Not the one you have for the 4.0 The manual says that adjustment of the fuel pressure regulator is necessary after a replacement has been installed. some models didn't have the pressure test fitting on the throttle body but the fitting PN8983 501 572 could be obtained from the parts Dept. I don't know how we're supposed to adjust it now.

[boxyjeep]

Finally available!  https://boxyjeep.com/products/renix-adjustable-fuel-pressure-regulator

 

[89 MJ]

Added to my list of parts to add to my MJ someday!

[watchamakalit]

Well crap. Looks like ill have to work some overtime.....

[pizzaman09]

That's really nice.  Looks like it does a great job of tuning in the fuel pressure.