Tom M'Guinn

Marren was in its original place? So, was this with a Lindsey Racing fuel rail? (I'm having the issue with a stock rail.)

Tom M'Guinn

Well I spent half the afternoon trying to find the source, and it just seems like the knocking is the sum-total effect of the line pulsations. Now I remember why I started in on the dynamat stuff...

Duke

Ah yes. Sorry, thought we discussed the LR rail here.
IMHO any knocking/tapping kind of noise will come from pulsations in the rail and not have anything to do with the fuel pump.

But with a damper in bad shape the increased flow from the 044 pump might exaggerate the pulsation noises. But that's just plain theory though

Guns951

I don't think that explanation works...Rob's old car had new everything (which I would "***"ume included a new damper), so why would it knock in that instance?

I'm curious as I'm about to get the lindsey fuel rail and an 044 or so

Duke

Because something in the design is wrong.

Guns951

Duke...this is why I love you explanations.

So basically this is something we have to live with?

Duke

Haha, I just had to mess with you after the "I don't think that explanation works" comment

The tapping noise is from the pulsations in the fuel rail, IMHO so if they are loud and you have a damper installed - something in the design is wrong.
Installing an additional damper has been proved to solve the problem. The one from 911 Turbo is an in-line design which makes it pretty easy to install.

I will investigate this further as soon (couple of months) as my engine is up and running (using the LR rail kit).

Guns951

I'm going to talk to Chris White about it as well. I can stand noise, when its coming from where I want it to! But with my exhaust I doubt I'll hear ANYTHING especially the sirens behind me

Thanks Duke

RolexNJ

I'd like to share something here for you guys, for what it is worth. These are facts too, period. When I had my old 3.0L car, Lindsey gave it to me with these mods, which were all brand spanking new.

LR Billet Fuel Rail With Dampner
SS Fuel lines
AJFR
LR HV Fuel Pump
55 lb injectors

Never, ever once did I hear any clunking or tapping noises. It was perfect in that respect!

Then I got the car back and we did the following upgrades:

LR Billet Fuel Rail With Dampner
SS Fuel Lines
AJFR
Bosch #044 Fuel Pump
83 lb injectors

As soon as those items were installed, I "immediately" heard what I would call as a tapping and clunking (not whining) noise coming from the back. I never looked into it, for ST told me this was the nature of the pump itself. So, I believed him. And I don't blame him at all for anything too. He did use, if I am correct, the same insullation that LR used for the first pump too. But ever since those minor mods were done, that's when all these issues started. So at least for me, I cannot say that there is a flaw in the design with the LR Billet Fuel Rail. However, I do know that earlier productions there were some issues, I believe, with the dampners, and it was brought to Lindsey's attention. And what is odd, is that both Tom and Tim have stock fuel rails, yet, have the same noises. Maybe it is the #044 pump?

Anyway, that is what I experienced, and I am still looking for answers. For I am building another car and don't want to deal with that obnoxious BS again with this car. If it was a track car, I could care less, but not this baby.

David Floyd

I have the stock fuelrail, Pauerman fuel lines, Lindsey Bosch HV pump and have the tapping sound in cool/cold weather, hot temps no noise.

So it's not the O44 pump itself.

RolexNJ

Ugh, WTF David, I am so lost!

Tom M'Guinn

David, what size injectors do you have and what is your fuel pressure? It's a small sample, the people who are reporting the knock all seem to have a big pump (HV is no slouch) plus 83lb injectors.

Duke, do you have a part number of model/year for that 930 damper? I can't seem to find anything matching that description on the online retailer sites.

The pump itself is not making the noise, but its flow and some other combination of factors seems to be creating too much pulsation at the rail, which is carried through the lines to make the muted thump/knock. I seems to come in to the cabin in large part via the little stud posts that the rubber anchor mounts attach to.

David Floyd

[QUOTE=Tom M'Guinn]David, what size injectors do you have and what is your fuel pressure? It's a small sample, the people who are reporting the knock all seem to have a big pump (HV is no slouch) plus 83lb injectors.
QUOTE]

72lb @ 38 psi

Duke

Exactly, the pump itself will never knock. That is common sense.
But as I wrote earlier, and some others write too, a high flow pump with large injectors could promote this sound. Injectors are either on/off and they always tick. Even stock you can here the tick's but they are consistent not that loud. Remember large injectors means lower duty cycle which creates fewer ticks and not as consistent and smooth.

The other fact is that the LR rail package itself really promotes this sound.

Puppans turbo cup has the 044 pump, 95 lbs injectors with stock rail and lines. NO unusual knocking/ticking at all.

Rich Sandor

Could it be that the stock fuel dampener is not sufficient for the big pump & big injectors?