I can only offer my direct experience data...

I have tuned dozens of Haltech equipped FC 13BT's - both with and without PD's.
If there was an obvious effect of the PD's on fuel delivery, I HAVE NO SEEN IT.
If there was an obvious effect of the PD's on fuel delivery, the fuel maps would've been drastically different.

See YearsOfDecay's post on his experience with not having a PD - it's very obvious that the Haltech(?) adjustment on fuel delivery was not having any effect on his problems with hesitations.
This is an OBVIOUS effect on fuel delivery.

Sorry, but I haven't seen this type of phenomenon on ANY of the Haltech tuned FC's I've worked on.
As I have stated on my PD page link, I only have direct experience with stock ND and Bosch "light blue" 1600's.
The people who have direct experience with PD's affecting fuel delivery have confirmed they were using alternative fuel injectors - this could be a big hint.
Chrysler "brown" 1600's are rumored to "react faster", which can imply their operation is different than other 1600's.
Sorry, I can't confirm this theory myself...it's just a theory.

FC's running stock injectors have never gave me a problem.
Even with S-AFC mods, fuel delivery was not significantly changed after removal of the stock PD.
If it did, the S-AFC would need to be retuned and wide-band readouts would change before versus after.

I cannot claim the mod is 100% safe.
I do admit that the cars with fuel pressure gauges show a slight increase in fuel pulsations when the PD was removed.
Does this mean everything is going to leak and blow up?
Right now, they are all still running...

You can take this however you like.
This subject gets rehashed every few months.
I wrote up my PD page for this purpose - it all ends up being a broken record.
To the people who have experienced negative effects upon removal of the PD, they are entitled to post their opinion.
To the people who have done the PD removal and have no significantly effects after this mod, they are obviously entitled to post their experiences also.

TO ALL THE OTHER (&#%& WHO DO NOT BELONG TO EITHER GROUP, SHUT THE )$)(%)$)(@ UP.
You have no right to tell me my direct experiences are WRONG.
Sorry, I like to try some very controversial things, and I do trust my own direct experiences rather than listening to someone who thinks it's wrong.
If it wasn't for crazy things like this, I wouldn't have come across my controversial modified flush procedure or this PD removal...


-Ted

 

Oh, and that Marren aftermarket PD retrofit...
This thing is NOT bolt-in.
Is there a write-up on parts and labor?
I think it needs at least one maybe two extra adapters to make this thing fit the stock secondary fuel rail?
I think by the time you get all the parts, it's more like $200 in parts?


-Ted

 

i am just forming the parallel setup seeing summit racing in so close to me. and i cost me about the same as an aftermarket PD.

 

Please keep this thread friendly. It's archive material, and I would prefer not to have to spend a great deal of time deleting and editing posts.

Thanks.

 

I'm the author of the Marren FPD Retrofit and wanted to put in my 2-cents.

The retrofit costs more than a stock PD, and is NOT a bolt in. However, it can be fitted without permanent modification to the fuel system.

I did it because I *preferred* to have a PD that's a better design than stock, not because I didn't trust the banjo bolt mod. In fact, I hold Mr. Lander's knowledge of RX7s in high regard. Plus, I'm looking to upgrade the entire fuel system over the next few years.

I'm NOT saying that a FPD is required for stock or even an upgraded fuel system, I think it's a matter of preference.

As Aaron Cake has said: Please keep things civilized.

 

do you have proof? and if so what other modifications were on the car? so far i havent seen any proof posted that has shown this will happen on lightly modded or otherwise stock cars.

that was explained earlier in the thread. because if a major company is putting great quantities of something out on the market with a warranty it wont break they dont want to take the risk of something possibly breaking. they try to make it last as long as possible, unless its going to cost them more that fixing a broken part would.

i never said it was your argument directly. it was for other posters with that point of view.

 

i tallied it up and it was a bit under $200, but your parallel system was like $250+ but a more complete and thorugh one. so im just inbetween wether to do the parallel mod or the aftermarket PD one. i may go the cheap route so i can have more left over for my BNR

and i never thought my idea would be so controversial. just keep it clean

 

What kind of proof are you looking for? You won't seem to accept the knowledge of the people who designed your car, so posting collected rail pressure variances from a pressure transducer would be useless.

There's no sense in posting proof to people who don't understand it, or want to understand it.

 

Although my diagram uses SS AN lines and fittings, someone has figured out how to use the Russells "socketless" hose and fittings - this makes the prices significantly lower.



-Ted

 

As stated earlier there are several Fuel Pressure Regulators on the market that have a built in puslation damper. I don't know if they are more expensive than the ones you are looking at, but if you are in a toss up between doing the parallel fuel system and just doing the pulsation damper, you can get all the benefits of the parallel system, and have the (benefit or safe of mind, or however the hell you view this subject) of the pulsation damper.

- Steiner

 

no i do accept the knowledge of people with experience with it (kevin and ted). from their experience a lightly modded or stock car will have no problem with it. and no one has posted any proof that a lightly modded or stock car will have problems from doing this mod.

 

I had a PD fail about a year ago, bought a new one from mazdatrix, 10 months and ~6k miles later it failed. If I didn't know much about my car it would be a barbacue 2X over. Installed a banjo bolt a month ago. 1k miles of flawless fuel delivery and no leaky fuel.

I will never put a PD on a FC again. anything I drive or rebuild will get a BB.

 

It's not that it is built-in.
Your typical FPR *is* a PD to begin with.
An FPR is just a PD with a bleed orifice.
So, although you eliminate the stock PD, the stock FPR still acts as a PD in the fuel system.


-Ted

 

do you mean using the barb fittings and just using fuel injection hose?

 

Yes, that's basically what it is.


-Ted

 

After reading this I just couldnt help myself...

Good info, thanks for the post. That's 3 posters with actual experiences, versus a handful with theories and the old "the manufacturer must be right" argument.

 

You mean can I give you a link to click that will pour forth screeds of supporting info, instantly sinking all opposing arguments? Yeah right...

Unfortunately a lot of my knowledge has been gained the old-fashioned way; many years of reading books and technical manuals, talking to people, etc, etc. I do not limit myself to simply believing everything I read on the internet, and have been teaching myself about stuff like this long before the internet was commonplace. I guess since I can't produce any of these sources for you, you'll have to continue believing I'm making it all up as I go...

So in fact you don't know, and are simply regurgitating someone elses post.

 

holy brickwalls! each to his own. obviously it works both ways.

 

in no way am i asking for gobs or pages and pages of information. and theres no way i believe everything i see on the internet. and i never said i thought you were making it up as you go along. i was simply asking for something to confirm that doing the mod will make me run rich or lean with a lightly moddified or stock car. something as simple as a wideband reading would suffice.

no im not, i know how warranties work and i know a lot about the business thats behind selling cars because ive done it. plus its really common sense and math.

 

well i plan on using the banjo bolt. im just going to get my engine streetported and rebuilt, and do the 5 lug swap (in progress) and call my car done. then i get to work on a vert

 

2 points.

in california we really didnt have a problem with the fuel systems until we got the crappy mbte/alchol gasolines in the mid 90's then the whole fuel system leaks, not just the pd although its usually the 1st thing.

2. saying that you've seen xx fd part fail within 5 years is a bad arguement. there are 3 parts on an fd ive never seen fail. the driveshaft, brake booster, and the headliner. ive seen EVERYTHING else break. hoods, the body, motors, the fuel injectors leak thru the electrical connectors, the seats break, the wheels, everything.

personally ive replaced a few s3/4 a couple s5's and ive never seen one that failed a second time. one of my cars is a 236k gsl-se and its still on the original damper, i almost replaced it in 99, but then i decided to wait, and its still not leaking (yes this implies prevenative maintenance)

 

QUOTE=RotaryResurrection]How about this, big man. Every car on the planet comes with a stock catalytic convertor. Most come with an air/smog pump of some sort. As well as various vacuum solenoids, hoses, valves, and the like (there are tens of examples, varying from car to car). Now, we all know that aside from emissions testing, you can remove all this from an engine and itll still run perfectly fine...all you need is basic fuel delivery, ignition, and compression. That other stuff is just auxiliary stuff, an afterthought by the engineers, to make the car more friendly for a particular area's requirements, or for the everyday user's comfort. By no means are they required for the engine to run properly. By your logic, removing or tampering with any of those parts (PD included) will **** the car up. "Oh, can't take that air pump off, it'll **** my car up". But, we all know the reverse is true...thus, the THEORY has been disproven, by EXPERIENCE.

.[/QUOTE]
The pd and an emmissions device are not in the same group of equipment, removing things you don't understand will usually have some consequence, but if you cannot understand why it is there, will you understand the consequence of not having it there? probably not...
Your car will run without the oil pressure sending unit, why don't you pull that to why you are it since they are sometimes prone to leak as well...You could drive around the block 5 times, and come back here say , see no oil pressure sender and my car still runs....The one day, you hit the right duty cycle at the right rail pressure and you blow your motor, for no other obvious reasons, look at your fuel system design... I had a lot of hard line in the system that really kept the rubber to a minimum for safety, but in truth further agravated the problem...
It took me awhile to nail down what happened to my car, I probably would have never found the problem had I not been turned in that direction by an efi engineer from GM, in fact it was a fuel problem on early Grand National that I was chasing, when I happened across the answer.... In truth, I had never thought about the oscillation problem, and I had read about removing the PD from for years on various rx-7 mailing lists, forums etc, so I did it and found the consequence of listening to people that think they know better than the automotive engineering world... Lesson learned, the hard way...
My stock na still has its original pd, and its going to stay that way, when it leaks, it will get a new one..
For reference refer to page 125 of your haltech manual. The Pd effectiveness is also covered in pretty much all efi tuning and building books currently available..

If Rotary Ressurection has a book on efi that he wrote, please post the amazon link where it can be bought..
yes the FPR and the puslation dampener are constructed the same way, except the PD has atmosheric on the other side of the diapragm, leaving the fpr by itself to deal with it, though is part of the problem, its very difficult for the diaphragm to maintain a set pressure when its being pounded with pulses...I am currently using the mallory which is advertised to incorporate a design that aborbs pulsations, with large primaries, as i said before, it doesn't really work.. Needle bounce is terrible, even with a guage snubber (pulsation isolater) in the guage inlet fitting..
And yes I drove around for a quite awhile without a PD, made alot of power to, till that one time....Max

 

We're talking about pressure waves that are travelling through the rails at the speed of sound (~3300mph in water, a bit slower in fuel), and injection cycles occuring as often as every 8ms (0.008 seconds). A wideband A/F meter that refreshes maybe 10-20 times per second isn't going to show you anything.

 

maybe ive forgotten because i havent read the whole post in a few days but werent you saying that doing this mod (maybe it was someone else) will make you run either rich or lean? which a wideband would show.

 

i wonder if you could modify the pararail setup RETed made to incorporate two Marren PD's tee'ed from the rail and the FPR...