Curt
02-08-2011, 01:46 PM
I've come up with a way to bump the base fuel pressure with our OEM fuel pressure regulator from the stock ~43 psi up to 55 psi. It's generally referred to as "crushing" the FPR.
By way of background, when WEB 3.0 was Rotrexing Grumpy's 2ZZ Spyder (over 4 years ago), he realized that in spite of a Walbro 255 and 630cc injectors, he'd run short of fuel/duty cycle at the top end. Bill was reluctant to "experiment" with his preferred solution - trying to crush Grumpy's FPR - so he shimmed it (how he did that is another story for another time). When I was deciding what to do with the fuel system for my stroker Rotrex'd 2ZZ Spyder I considered a return system (as Sammy Sandbag and WYOWRX have chosen to do), but instead opted for shimming as Bill had done for Grumpy in order to achieve a 55 psi base pressure (which when combined with my 630's and Walbro haven't yet hit the 80% duty cycle point yet - but only 90% tuned at this point). Not quite as elegant as a full return system (from a purist's perspective), but a heck of a lot more economical (I don't even want to guess how much MWR charges for a complete return system, plus a bunch of work to install).
The method for shimming was to run a small gauge stainless wire thru the FPR to basically bind up a couple coils of the spring in there. But that's a bit shade-tree and I was still curious about the possibility of a more permanent crush method. After some research on outfits selling aftermarket supercharger kits for other cars and who supplied with their kit a simple, foolproof FPR crush tool, and I could see for myself how it was supposed to be done, I figured I could probably find a way to make such a tool. And with Corky's generous help, I was able to. I picked up a couple of used FPR's from Car-Parts.com and started experimenting, and I was able to nail it.
So here's the good part that some of you reading this want to know: It's FREE (well, almost). Send me your OEM FPR and I'll crush it to that 55 psi figure so it'll be a slick plug-n-play (except that you'll need to re-tune your ECU/EMS). Include in the package $5 for Priority Mail return postage, and I'll turn it around and get it off to you in one day. Santa Claus came late this year guys! I won't loan this tool (so don't ask) and it would be too much hassle to try to make and sell them. And for $5 and using the 630 injectors and the Walbro 255, where are you going to get a fuel system that'll support a RWHP in the low 300-range.
PM me if you're interested.
By way of background, when WEB 3.0 was Rotrexing Grumpy's 2ZZ Spyder (over 4 years ago), he realized that in spite of a Walbro 255 and 630cc injectors, he'd run short of fuel/duty cycle at the top end. Bill was reluctant to "experiment" with his preferred solution - trying to crush Grumpy's FPR - so he shimmed it (how he did that is another story for another time). When I was deciding what to do with the fuel system for my stroker Rotrex'd 2ZZ Spyder I considered a return system (as Sammy Sandbag and WYOWRX have chosen to do), but instead opted for shimming as Bill had done for Grumpy in order to achieve a 55 psi base pressure (which when combined with my 630's and Walbro haven't yet hit the 80% duty cycle point yet - but only 90% tuned at this point). Not quite as elegant as a full return system (from a purist's perspective), but a heck of a lot more economical (I don't even want to guess how much MWR charges for a complete return system, plus a bunch of work to install).
The method for shimming was to run a small gauge stainless wire thru the FPR to basically bind up a couple coils of the spring in there. But that's a bit shade-tree and I was still curious about the possibility of a more permanent crush method. After some research on outfits selling aftermarket supercharger kits for other cars and who supplied with their kit a simple, foolproof FPR crush tool, and I could see for myself how it was supposed to be done, I figured I could probably find a way to make such a tool. And with Corky's generous help, I was able to. I picked up a couple of used FPR's from Car-Parts.com and started experimenting, and I was able to nail it.
So here's the good part that some of you reading this want to know: It's FREE (well, almost). Send me your OEM FPR and I'll crush it to that 55 psi figure so it'll be a slick plug-n-play (except that you'll need to re-tune your ECU/EMS). Include in the package $5 for Priority Mail return postage, and I'll turn it around and get it off to you in one day. Santa Claus came late this year guys! I won't loan this tool (so don't ask) and it would be too much hassle to try to make and sell them. And for $5 and using the 630 injectors and the Walbro 255, where are you going to get a fuel system that'll support a RWHP in the low 300-range.
PM me if you're interested.