So Im trying to set up my 01 XJR with an adjustable fuel pressure regulator for various "reasons". Ive gotten just about everything needed but have so far been unable to find a suitable fuel rail adapter. Does anybody know of an aftermarket one that fits this application? I think the port side is 14mm but dont quote me.

 

So after some trial and error I managed to find an adapter that I was able to use. Only thing was it doesn't match the regulator exactly, the flange is spot on but the port differs in that it lacks a shoulder after the o-ring. I got around that by using a slightly larger o-ring then what came with it, ( but the same as what's stock on the regulator) and backed it up with two thinner ones stacked behind it for support. Bolted right up and so far no leaks even at 65psi. Adjusted it down to 38 and 45 without vacuum reference.

 

Sorry for the last potato pic

 

Nice work!

im about to do the same

Anyone found a perfect fit adaptor?

 

Not trying to resurrect an old thread but wanted to update this, I was never able to get the adjustable fpr to work properly. It would run fine at idle and midrange but at wot it would throw rich codes on both banks. I switched back to an oem fpr after much struggling and haven’t had any trouble since……well fuel pressure trouble anyway. It’s still a jag.

 

You could offset the rich codes with a ‘big n little’ upgraded pulleys.

Do you think (or know) your adjustable FPR could lower fuel pressure at WOT? Yes, I know you said it was too rich at WOT but, do you know why? I think I want to have some type of alcohol (or E85, **not nos**) injection setup spray before the TB. I want to spray a considerable amount and be able to reduce the fp @ WOT so I don’t have an over rich condition.

 

That I don’t know, I’m guessing it could if you had a way to manipulate the vacuum reference accordingly, like a vacuum/boost source that rose then dropped, on an arch rather then linear incline. You might need to go with something way more purpose designed to both increase fuel pressure as manifold pressure increases, but then decrease it at whatever point you decide to introduce / switch to e85.

 

“You could offset the rich codes with a ‘big n little’ upgraded pulleys”

Also a mod to fix a mod is my favorite kind of mod.