chaadster

Hi Everyone,

I'm hoping that some of you out there won't mind sharing your thoughts with regards to the benefits of my using an AFPR/RRFPR.

I'm looking for slightly snappier throttle response, and of course, a bit more power would be nice!

My car is an '88 auto with an Autothority chipset and an RMB. It is otherwise stock. Would an adjustable/ rising rate (are all RRFPR's adjustable?) offer any seat of the pants improvements, or would I just be burning up more gas?

Are my expectations of noticeable performance gains reasonable from a RRFPR?

Any thoughts are appreciated!

Jim R.

Without more mods to the car (headers, x-pipe with/without cats, etc.), I probably would not bother. There would have to be some dyno time to play with different fuel pressures to assess any gains/losses. I also don't know what the chips do to the fuel maps vs stock-do they just play with the timing or do they also adjust the fuel maps in the LH? You will probably see more gains by getting the injectors cleaned, the MAF rebuilt, and making all systems are working as they are supposed to unless you want to go further down the slippery slope of mods........

Hope that helps. You see which direction I took.

Jim R.

Gretch

Second the motion.....in and of itself a RRFPR won't make much if any difference. You need some modification to your engine where raising the fuel pressure under load conditions will make a difference in performance. The fuel pump, FPR, injectors, mapping computer and dampers were designed to more than cover the operational range of your engine in stock configuration.

Also re the dyno comment, this is good advice. It makes no sense to add manual tuning capability to your car if you do not intend to tune it properly. RRFPR do not come "pre-tuned" ........they are one of several components you add for unique custom tuning.

MarkRobinson

I went from 282rwhp to 302rwhp on my '86 car just by dialing out the extra fuel that Authority programs into their fuel maps (for their safety) on the dyno 6 years ago.

AA programs for rich, but too rich. 20rwhp too rich in my case.

Mark

chaadster

Thanks for the replies, guys. It seems like there's a pretty good list of stuff to do before I really need to start worrying about the fuel pressure!

bigs

Or, another way to look at it...

Presently I need new injectors. And someday, I'm not sure yet, but someday I might give in to the temptation to supercharge.

So, I'm going with 40 lb injectors (I think that's what they are) as well as a RRFPR. I'm not expecting major HP gains, but if the day comes that I do install a SC, some of the fuel stuff will have already been done.

MarkRobinson

40# injectors are flow twice as much (dun, 19#) as your stock injectors: which are already good enough for 400hp. 30# injectors will allow your O2 to proplery correct your AF while driving normal, possibly w/o needing to lower your fuel pressure to compensate, though I suspect you'll get better mileage if you do. Also, 30# injectors suffice well into the 600hp range, and, they're only $230 out of Summit or Jegs. 40# injectors will cost you a few hundred more as they are not as main-stream as the 30# Ford Motorsport injectors (you'll need to purchase new injector-at-the-manifold o-rings as the motorsport o-rings on the nipple of the injector are too small.

.02.

Gretch

Mark took the words right out of my mouth..........40# ers sound like way too much......only guy I have heard using them is Lag or Z and they were talking about adding an atmosphere to an already boosted shark......

Ketchmi

Bigs made a mathmatical error as we discussed 30# instead of 40# so you can relax. I have 30's in an 89' that runs 5psi (at the moment, soon to be 11#) and it passed emissions easily. It runs smooth and has no problem controlling the A/F but still provides enough fuel for an estimated 370rwhp uncorrected. (415ish rwhp at sea level)

Gretch

I am running 30# ers with as much as 10psi and I had to lower my fuel pressure from stock at idle to get the car to run right. Dual function RRFPR takes over after that and we are green at WOT to redline.

Benton

30#ers would be good on an SC, but wouldn't that just cause an extremely rich condition up until you SC?

Ketchmi

Not if you are running in closed loop (w/O2 sensor) and you reduce the fuel pressure to the low 30's. Runs fine and clean and is within the allowable parameters of LH control. If you leave the fuel pressure at 45psi, then it will run fat as hell hence the need for an adjustable FPR. The added benefit of a rising rate is a bonus as I have seen a lot of engines have a lean surge before the MAF takes up the slack upon activation of WOT.

With my exhaust work on my 86.5', I raised the fuel pressure a considerable amount to get enough fuel for WOT running without idle or low rpm problems. Unlike Mark R. I richened mine to provide 12.5/1 at WOT. This one is not supercharged but dyno'd at 257rwhp uncorrected. (290+ rwhp at sea level)

MarkRobinson

I'll have some good reports in 1.5 weeks as my dyno-testing will show the difference the AFC will make. Doing this in lieu of the regulator as my hole is too big. Hey Dave: I wouldn't say I had a lean surge, as it was on my red car & is on my grey car, exactly in the middle of the torque curve, regardless of where i nail the gas. Back 6 years ago on the dyno, we just ended up starting the runs from 3500 to avoid spending too much time in WOT in the lean dip. Seemed to work, still got 296rwtq/302rwhp...though with corrected fuel, torque could have gone up I'd say at least 10rwlb-ft.

M>

bigs

Yep. My bad. Dave's never steered me wrong yet, so I think I'm gonna go with his suggestion. I'll report back if anyone's interested. Probably won't happen until next month.

worf928

Bigs, Why do you need new injectors?