pulsation dampner
 

lets say we get rid of the dampner and replace it with a banjo bolt.

get a marren pd and put it in line between the upper and the lower fuel rails using a tee.

would that be enough to solve the problem?

It would be much easier to rebuild in that spot and you would'nt have to worry about clearance.

Go for it..

A long loop of fuel hose would probably work also.

I have no pulsation damper. I have no problems.

It's there for a reason and should be used. Every electronic fuel injection system has a pulsation damper to smooth the shockwaves from the injectors opening and closing.

I have not seen proof of any downsides to the PD removal, even though there are particular members who offer very strong arguments against it.  A lot of it is regurgitating info and no real-world experience that back up these claims.

I've done it on stock FC's.
I've done it on highly modified FC's and FD's.
None have killed their engine or showed any weird phenomena due to no PD.
This is my real-world experience and not some regurgitated info from references.


-Ted

Here we go again...

I am not a fuel system engineer, so unfortunately, there are times when I have to trust the higher knowledge of those actually designing the system. The has to be a reason why 99% of EFI systems have a pulsation damper. Manufacturers don't just put extra parts on without a reason (except, perhaps, for that ridiculous cold-start resevoir). Unless you have specific, real world and lab proof (for example, connecting a pressure transducer to the fuel rail and driving the car under all circumstances while data logging the whole event) that the part is not required, it only makes sense to leave the part in place.

We've done Haltech tuning on PD, no PD, aftermarket FPR and none of it changes the fuel maps.  That's good enough proof for me.  If there was a problem it will quickly pop up under this condition under the EGT and wide-band.



-Ted

I have seen pulsation dampeners used on a carb'd MG Midget. Most people explain the PD's for use in a fuel-injected system. They must not be fuel-injected related though as I have seen them in this carb'd car.

how much does another banjo bolt cost from mazda, if i wanna yank the dampener? and do they come with crush washers?

I don't remember seeing any PD's on GM vehicles (camaros/firebirds)

Ok I'm not going to call my self an authority on PDs, but God knows I've lost sleep over it. I've also spent the last 3 months making a new and improved PD. At anyrate Ted is correct, the PD is much like the Cold Start crap. at most, it really doesnt do anything, other the start fires. Also I was under the impression it smoothed out pulses from the pump, not injectors, but I could be wrong about that.

Solution: Just run some SS line from the fuel filter to the rail and you'll be all good. Or, do what I'm doing, and go all out and changing the all the fuel lines to SS. :) actually, I'm changing all my lines to Stainless Steel.

-From Nevada!
Christian (see I can't even stop thinking about RX7s while on vacation! )

Re: pulsation dampner
 

If you were going to do that, and use the Marren PD, it should be attached to the main fuel rail, not between the two. The FP Regulator acts like a PD for the secondary fuel rail.

Can you replace S5 PD with banjo bolt?? If so, what size banjo bolt and what other things would I need for that? Some people said S5 can't use banjo bolt and I want to know if it's true.

No, the S5 PD is welded to the fuel rail, if you wanted to replace the PD with a bolt or an adapter for an after market PD you would need a S4 fuel rail

ok, i have an S4. what are the threads for the fuel rails? 6 or 8mm? i also want to convert all my lines to SS.

when i was installing my motor, i shook the PD and noticed that it rattled. and there is a dirty yellow plastic cover over it. i took it off and a screw fell out. so, i screwed it back into the center of the PD. aparantly, the screw has been out for a while now, even when i was running my old motor. what does that screw do??

I guess a set of hammered injectors and a popped motor is not "real world experience"...
give me a break....
I would have to say those that have experienced it, are most likely people that have moved on to a higher output level than most people experience.. I would also say there are alot of people out there have popped a motor and wondered why , how many times have you read," all the a/f's were good, the timing was good, it just let go".... well I think that phenonem is in the fuel rails..
Will it show up on a guage? probably not...
Will it show up on a wideband, probably not, although it might show up on a narrow band, much like the closed loop in that regard, its to fast of an event, and you get an "averaged" readout on most widebands..
Is it there all the time? No, it seems every fuel system has a certain resonance, where the fuel delivery will become unstable...
You can basically corral this occurence to batch injection, in sequential injection, the pulses according to GM cancels each other out.
You can read about this on visteon.com
Kinsler.com
Injector.com
delphi.com

For other rx-7 owners views

http://www.sa22c.org/cat_12/36391/
Bosch shows the puslation damper in all of their fuel injected schematics, even in Teds beloved "maximum boost" its in there as well
The best read is fuel injection installation performance and tuning where there is a significant write up on it, in the design of fuel rails..
Its in alot of SAE the papers on fuel injection and fuel delivery, its in the haynes efi manual, other car manafactures to use it include Honda, Volvo, toyota, nissan, chrysler, etc etc.
How I found about the problem, is dealing with a problem on a buick Grand national, that wouldn't set a code for a misfire, I was given the phone number for GM technical support, in trying to diagnose the grand national, I was enlightened to the injector flow rates changing on batch fired cars, and ijectors having a higher failure rate than sequential fuel injected cars, and the pulsation hammering phenonem. The less rubber you have in the fuel line , the worse it gets...
If you can save a buck on a car, and you make a million cars thats a million dollar saving, they aren't putting the pulsation dampeners in over a million cars, just for kicks now are they...Max

RETed posted his own experiences with no pulsation dampener. I would count this as "real world experience".

What you "think" is happening to other vehicles is not "real world experience".

PD's may not be useless, but I fail to see your factual input on this, Maxthe7man. Certainly automakers don't spend money on useless parts, but your guesses on other motors failing is not proof

Since I know PD's have been installed on NON-fuel injected cars, I know the protection isn't only for the injectors. It seems, in some more research, are designed to protect the fuel pump.

If the PD's double as protection for the injectors, I can't say. I have no evidence to say that. I certainly wouldn't go out and say they don't protect the injectors, but thats because I wouldn't overstep the boundaries of my knowledge.

Dude,

Max and Ted are arguing on like 2 different threads... WTF?

I am not arguing with Ted, Ted is arguing with the rest of the world on this one, it seems his experience on his mostly stock FC outwieghs what most of the auto manafactures in the world think, along with leading manafactures of efi equipment.. Most of Teds real world experience is unprovable, you don't get 10000 posts working on high output FC's and FD's, you get it by sitting on the internet blowing your own horn..
I know what failed in my car, that is a real world experience, on high output rotary...
If you are gonna chance a 2000.00+ motor, on skimping on a 100.00 dollar part, you deserve what you get...
Maybe Pyrojunkie would like to tell us why they are there, they do not protect the fuel pump, the check valve on the outlet of the the pump would close with a wave of back pressure.
I dunno, I am tired of explaining this, if you are dumb enough to risk your motor when there are nearly a 100 credible sources written by people alot more credible than Reted, then all the power to you...max

Since I have seen this questioned a million times I did as much research as I could on the purpose of the pulsation dampener. In other applications, the only protection I can see it designed for is the pump. If the protection was for the injectors, then it wouldn't be found on non fuel injected engines. I have seen for myself though they exist on such engines.

So Maxthe7man, you say your engine problem happened from no PD? That would count as "real world" proof. Strange, you didn't mention your car in the first post.

Max: Dude, no need to attack him personally. If you wanna argue about PD, then do it but no need to attack him like that. Ted has been very helpful to the members here and always kindly answered everyone's questions.

You're just taking this way too far. It's just a discussion about whether you need PD or not. CHILL OUT. :)

http://www.autoshop101.com/forms/h42.pdf

PULSATION DAMPER:

The rapid opening and closing of the injectors cause pressure fluctuations in the fuel rail. The result is that the amount of injected fuel will be more or less then the desired result. Mounted on the fuel rail, the pulsation damper reduces these pressure fluctuations.

Page 19.

I have a PD, and I intend to keep it. But if you all want to remove it. Knock yourselves out.

Rat

To tell you the truth, I have never seen pusation dampener on carbed vehicle, I did just have a carter race mechanical pump part though, and there is a fuel pressure regulator, no dampener by any means though, so I don't know where you got your info from ? Links?

Rookie84, not and attack, just an observance...
J-rat, yep.... I guess you can lead a horse to water eh?,,

Well, now I wouldnt put it like that.

I just present the facts. I respect Ted, and I feel that he provides alot of support to the rotary community. I just disagree on this point. Does that make me right and him wrong? Honestly, I dont think so. Its like the ATF argument, or the E- fan argument, or the fuel pump cutoff switch argument... There are 2 sides.

I run an E-fan (unshrouded too!.:eek::))
I run a PD
I wont put ATF in my motor..EVER
And I use fuel pump switches sometimes.

So am I right on those points or am I wrong? I say I am neither right or wrong. I just do what I think is best for me.

My first TII lacked a PD all together it was an 87. MY current one has one, and it's highly modded. I didn't know the 87 was missing one, until I hit a bridge abutment. Never felt any form of bucking. Flooding, but that's common on those. So? I don't know. I know personally some Automotive Engineers and they're not all there.

YES they're engineers, but just because you're a janitorial engineer doesn't mean you can build a bridge. Or design a kick ass mop either.

Ted offered his personal experience, So Max don't come off and have this "small penis" syndrome. If you disagree then do so, and leave it at that. Seems to me like you came off a little aggresive, for no reason really.

Shouldn't the dampner work just as well between the rails instead of being at the end of the main rail?

My info on carbed vehicles having PD's is from a MG Midget my father owns. He asked me the same question one time when I came over to help him work on his car; "What is a pulsation dampener". So there isn't any links, I guess I can work on getting you a picture. Really its only my word you can take for it now.

I am still trying to understand your experience though. Did you say you had a motor fail because you didn't use a PD?

killinfoo66: since no one "really" understands the PD, it would be arguable on how effective its position is now.

I bet not one of the anti-PD people can asnwer this one simple question.

If it's not needed, why does every EFI car have one?

It's not a hard question, but every time I ask it in these threads (many, many times...), nobody answers. Ever.

The problem I see here is that Max is giving you his experiences with his car, as well as the links to discussions and other literature on the subject, written by very knowledgeable people.

Ted on the other hand keeps telling us he has "real world" experience. He refers to "ours" and "we". In order for his comments to have ANY merit he needs to tell us who "ours" and "we" are. Otherwise it's just him making shit up. I have no problem wtih his style of arguement, but he needs to show some evidence of his experiences. I for one am not willing to be led to slaughter just because the "almighty" ReTed asks me to follow him.

There are a few people here who are saying they've done a ton of research on the topic, but when it comes to the facts their way off, leading me to believe they either didnt do the research they say they have, or they don't understand the principles involved. I'm not sure why people are fighting this tooth and nail, maybe their affraid to go back on their word and eat a little crow. From reading the links Max posted, and checking out a few books on the topic from the library of my local technical institute it's become clear to me. Regardless of the type or model of FPR a pulsation dampner is beneficial to any car that has reliability to think about.

Not to get off topic (the argument), but fstrnyou posted a good question, that I am also curious about.. What does that screw in the middle of the PD, underneath the yellow plastic cap, do? Mine was also loose, although not falling out or anything, I screwed it down a bit, then put it back on, so far my engine hasn't caught fire, should I be wary?

Thanks!
~Wonko The Sane


And now back to the argueing

I'm not anti one, Mine just didn't have one, and I never noticed anything.

RETed only posted that in has never affected any of his cars he has tuned. He only said from his testing that he had enough proof for himself. He mentioned only that it was his real world experience and not info read in an article.

On the other hand, Max came into the conversation he has a Grand National that failed because of the PD(or lack there of, he hasn't explained yet). He has even mentioned having a high output rotary car fail because of the PD(or lack there of, still no explanation). I would give him credibilty, if he said these cars failed because of no PD. I certainly don't appreciate all the name calling he is sending out.

I am not for or against having a PD, but I seriously want to know its function. Maybe its has a function to keep fuel flow constant from injector pulses? To me, my real world experience is having seen one on at least one carb'd vehicle. Besides the RX7, I don't remember having one on any of my cars(all fuel injected), so I am still looking into if they did have one. For now though I just want more info on the PD's function.

Ya I know, that's precisely the problem. What cars? What customers? What experience?

Fair enough, but let's not single anyone out for name calling lets face it Ted has done is fair share, in this a other threads.

That's what's being asked of you and others. Go and read the books Max mentioned in this and the other threads. Go and search on the web yourself. I know every honda I've owned has had a PD, that includes new and old models I can go take a picture of the one's on my CRV and Prelude that are sitting in my driveway. All you have to do is turn a tap on in your house, shut it off fast and listen to the pipes bang to realize the principles involved here.

So I pulled the "spider" & ran heat shielded rubber hose (3.5 meters total) from the firewall to the rails.
The PD stays for now, but it leaks, it's gone.
The hose is my PD..

Where's your proof?
I here a lot of claims from you, but I never hear of proof.
You keep "hiding" behind your references.

I have never heard that in my life.
All of the ones running EGT gauges have mentioned elevated EGT levels.  See the thread on NoPistons about the car Steve Kan was tuning that keeps letting go on the dyno (several times); this car is almost an identical set-up as others cars Mr. Kan has tuned, but he does mentioned elevated EGT's which cannot be explained.
It shows your ignorance on the whole subject of EGT's.  if the EGT is in it's safe range, it's next to impossible to kill a motor from detonation.  This also shows your ignorance on the relation of PD's to fuel delivery to EGT's.  If there is adverse effects from the missing PD, there *IS* going to be an adverse effect on fuel delivery.  Ergo, EGT is going to be affected due to the inconsistent EGT.  Now you're talking yourself in circles which makes no sense...which I've already claimed you're illogical.

WAG.

Again, you show your ignorance on EGT's.  Please stop claiming you know the relationship of EGT's on engine condition cause you're jsut spewing misinformation.

I don't like EGO's or UEGO's, but you're showing more ignorance on the subject again.  I'd suggest you do your homework before spewing more misinformation.

The question is this resonance affecting fuel delivery during the fuel system normal range of operation...that's the million dollar question.

Since we're just arguing in circles...how's about this deal.
You pull your PD and run an aftermarket FPR exactly how my parallel fuel rail diagram states.  If you blow the engine, I'll buy you ANY 13B engine to replace yours.  I wouldn't think you would allow me to build you an engine....pshaw...so the deal is you pick the builder (Racing Beat, Mazdatrix, Atkins, Don Marvel, R.E. Amemiya, FEED, PanSpeed, I don't care), I pay for the tab if you provide me conclusive proof the non-existance of a PD in the set-up causes the demise of your engine.

Put your money where your mouth is or JSTFU.


-Ted

Please keep this thread friendly and free of flames. Thanks.

You always seem to make it a point to state this all the time.
I dunno where you get this implication from, but it's not my intention to do so.
I think you're inferring the wrong point from my postings.

No, I think you're reading into this too literally.
I read a recent Turbo (or someting close) about PD's, and the main points were 1/2" ID fuel rail, very long fuel rails, and multi-point injection.  The FC fuel rails almost break all of these rules.

If you're talking about "scientific proof", you're right.
I do not imply my experience is a thorough, scientific proven "truth".
I'm sorry if my experience isn't good enough to change your views.
I present them as a "data point", not as an end-all answer.

You kindly forgot about the TeamFC3S forum post which you blatantly "defiled" my diagram.  THIS is what I'm most pissed about.  I really don't care about your stubborness to not believe me; I firgured it out long ago (wow, can you believe that?) that you won't believe me even if it was written in the dictionary.

http://www.teamfc3s.org/forum/showth...threadid=29559

THIS is what pissed me off.
THIS is what I'm defending.
THIS is where I think you're wrong.


-Ted

And for that matter, personal arguments between Max and Ted should be taken elsewhere.

You're welcome to edit anything I say.
Hell, you're the mod, you can delete, and I can't do anything about it.
You know the history between us.
You even started a thread about me in the Mods forum, so I understand. :)


-Ted

Couldnt agree more..

Isnt the point here that you do whats best for you?

Ted removes PDs, I keep them. You dont see me and Ted arguing all day about the point...

I generally don't edit. I delete or close, then warn or ban.

I don't always see eye to eye with Ted on matters, but the diagram shown works fine, and has for many more people than just myself. The PD is in the FPR, atleast any modern "nice FPR" There does come a time when reality means more then theory. In theory, I could say this phone on my desk keeps tigers away. I don't see any tigers so it must work.

See, I told you nobody would answer my question. :rolleyes:

I answered it right here:

Course I am not anti PD.

Well you and I know why they're there. I was actually hoping for an explanation from someone who thinks they're not necessary. ;)

I gotcha!


Watch out. We are postwhoring again...:rolleyes:

Don't hold your breath sir..Trying to get Ted to explain that is like trying to push piece of rope...
And Ted, I guess the difference from my point of view and yours is mine comes from about 150 rwhp more experience...max

All I know is they suck when they leak huh rat.....:eek:

...
And how do you think I came across this?... get your cheque book out, I ran without a PD, and parallel rails, and the motor with a toasted front rotor, with injectors that drip fuel like an eye dropper...I am in the process of putting a serial looped fuel rail back in the car with a pulsation damper...
Anyone know what makes the PD screw fall out? is it the constant pulsing?
As for ignorance Ted, apparently you need a a course on reading, Where did I say EGT's, now you are just making shit up.. Again its your logic against the world, I can produce 20 books and gazillion links, on why the PD is there, however I have a hard time finding people with a high horsepower REted tuned car to back up your claims...Max

Yes, they will cause you to have to pull up the UIM a few times looking for a stupid leak..:mad: