DanielBlakley

Alright the manifold I am using is hitting the goddamn pulsation dampener and so I can't put it on all the way... I can't think of any way to move the pulsation dampener and I tried getting a banjo bolt but no-one carries it in that size... the car is an S3... someone help me because this is pissing me off.

gsl-se addict

iTrader: (3)

I think that we need more info. It sounds like maybe you are tring to install an S5 manifold on a GSL-SE, but that is just a guess.

As far as the banjo bolt, I am not sure where you could get one locally. I know that you can get something online. Maybe search on here for "banjo bolt pulsation dampener" and see if you can find where others have picked one up (some people remove the PD and replace with a banjo bolt).

trochoid

iTrader: (6)

Banjo bolt for S4's is: Earls part# 997591 12X1.25. Don't know if it fits any other rails but I suspect it may.

DanielBlakley

That is the correct size banjo bolt although I was hoping to keep the pulsation dampener...

mjm4jc

Some people have removed the PD with good results. I think there is something in the archives on this. It may be in the throttle body mod thread.

Mike

DanielBlakley

Yeah I saw a couple things written up about it but nothing with tests or actual data just people saying "i don't feel a difference"... IMHO thats as uninformative as saying nothing at all... Alright so today I took everythgin out so I could actually get to the fuel rail and went a little overkill with some fitings and then tested the results with and without the pd... my data showed absolutly no differenece between the two with the exception that during a full throttle to fuel cut situation you would get a quick fuel pressure spike that is slightly more pronounced in the non-pd setup... This should not be a problem for two reasons... one the injectors are off at this point so the fact that you are multipling by a higer coeffecient to get the amount of fuel injected doesn't matter: your multiplying by zero... second when the fuel spike was at its worst (while I'm trying to make it spike) it was still less than 15 psi pressure which shouldn't be a big deal as I know people who have run the top feed denso's reliabley on a consistant pressure much higher than 55 psi... For those of you who are worried about the shock cuased by the spike damaging the injectors, due to the way the fuel rail (mine at least) is built and the way the fuel comes into it the shock is mostly absorbed by the pressure regulator and is barely noticable at the injectors... By the way I did notice that the fuel rail holds its pressure much more constant without the pd... I ran a lot of tests on the pressure relationships of everythign etc. so if anyone is interested or needs help with soemthign else surrounding the fuel rail pm me since I have all this data just laying around now.

As for why the pd even exists... well they are used in a number of industries that use liquids in order to dampen the violent shock caused by closing a valve with a high velocity liquid moving through it. Since liquids don't compress like gasses all that pressure and momentum* behind the liquid in the line closest to the valve causes the liquid to bind on itself, so ti speak and search for another way to release its pressure. If its violent enough, before the pressure is relieved back through the line it will bust wahtever is containting it. The only thign is there is just not enough pressure or velocity for this to be a problem in our fuel rails (at least not one set up as mine)...

I'll post pictures of my setup sometime tommorow

*I know momentum really has little to do with it, its all about pressure... It was easier to illustrate this way though.