Fpr

So as soon as I get my tax return back the gsx is getting 990 or higher injectors a 255 walboro, dsmlink, and a 60 trim. And some new fuel rails and misc crap.

My question to all of you is. How necessary is an FPR. With Dsmlink does it matter or not if I have one? Now I know alot of you will preach the greatness of an FPR but honestly around here no one runs them. And these are people with 400hp+ setups. People around here are quick to slap on a 255 and have no regrets. I have talked it over with several people here and the guys at the shop and they all agree while an FPR is nice it's not necessary. I talked to them extensively about it and they say the biggest difference is a little rougher idle.
But with dsmlink this is always eliminated.

So why is there so much emphasis placed on FPR's? I am just curious as to what everyone here thinks and If Kevin could chime in with his opinion that would be great.

I just want to know if I should get one or not. The guys here say no, what do you guys say?

You will need a fpr, i asked the same question that when i got my dsmlink would need a fpr and they all said yes.

So scottsee helped me out and this is the best one to get!!!

http://www.importevolution.com/product_info.php?cPath=24_45&products_id=3629&osCsid=21dbc8079dd409114871d02e89b87e41

My understanding is that not running an afpr with a 255 will over run your regulator causing the pressure to increase subsiquently causing you to run rich and that cannot be tuned out because the only way to prevent it is to lower the pressure and the only way to lower pressure is with the regulator, I'm probably off but I think I'm close. I was wondering this same question to, my friend told me that in his setup he only had a problem when he first started it and then it was normal so I guess I'm not sure

I agree, if you are going to put that much into you're engine, I would do it right. The Aeromotive AFPR's are only like $140 from SBR so they arent overly expensive. The Megan ones are only $70, thats what I will personally be getting.

I'll let you get the megan first and and then you can let me know how it works :wink:

So why is there so much emphasis placed on FPR's? I am just curious as to what everyone here thinks and If Kevin could chime in with his opinion that would be great.

He has covered it extensivly on this site already, give it a search..

I have explained this in great detail, but I'll toss up a quick blurb anyway. If anyone does do the search, post hte link here so people searching in the future are more likely to find what they are looking for.

Be careful not to quote how much HP someone makes with or without an FPR, since at full throttle/boost the FPR overrun issue becomes totally irrelevant. It only applies below some specific boost (and therefore fuel) pressure, namely at idle and cruise since we are either at idle/cruise or WOT, and rarely in between. ;) BUT, a quick example, fuel pressure overuns to 50 psi. Base should be 43 (2g example I guess). So at anything below 7 psi the fuel pressure is too high, and over 7 psi the FPR will take over and work properly again. The ECU however has no idea this is going on. Many poeple tune around it, but that does not mean that running without the AFPR is "ok." :) It's up to the individual and his or her definition of what is acceptable.

So if I understand what you are saying. If rough idle is acceptable you wouldn't need an AFPR? Not saying I'm not going to get one, but just out of curiousity.


Also, the info.

http://www.automotiveforums.com/vbulletin/showthread.php?t=390338&highlight=AFPR

That's the basic idea. Not so much a rough idle, but the trims will be maxed out leaving the ECU with little to no control over idle/cruise AFR, making things a bit rich, and you'll probably never pass inspection. It can make it idle funny, but usually the ECU has just enough range to keep it running "normal." Some poeple only care about WOT, and for them an AFPR isnot really necessary. I like my tuning to make sense however, and I do a lot of mileage, so an AFPR is mandatory for me.

Wow, I'm glad I read this thread. This and that link taught me so much about fuel systems. I'm going to be able to apply it to my car soon.