Over the past few months , several members have noted off boost flat spots between 2k-3k RPM. It appears that a few members have purchased and installed the new CJM damper rails in attempts to resolve this issue. If anyone would like to share their results, the information would be much appreciated. Thanx

 

i have the CJM damped rails along with a big marren fuel damper and my lean spot at 2700rpms is gone now.

 

Rich, how do you have your Marren fuel damper setup?

 

it just T's in on my -10AN feed.

 

str8, any reason you are running a double dampner system? thoughts on how just the cjm dampened rails would be without your marren dampner?

 

^ I think that he had the Marren damper from before he installed the damper rails... I am not sure if he has tried the rails without it?

 

I had lean spots at 1900, 2400, and 2900 rpms in low throttle accel. It would hit 18:1 or higher and buck. It made cruising through parking lots almost impossible. I tried tuning around it for over a year. Hal worked his magic on it as well and it helped some but there were still spikes between 16:1 and 18:1 in those areas.

After installing the new rails I still get a little bit of a lean area in those places but they are low 15's which isn't far off from my 14.7 target so in truth i think it fixed it. I haven't adjusted the map or anything since adding the new rails. I just put them in adn drove it and the 18:1's dropped down to 15:1 at most i've seen is mid 15:1 in those same areas. Now i think i could probably do some minor adjustments and make it perfect but since the car doesn't buck I decided to leave it alone.

g35
cjm stage 3 (twin pump)
HKS 1000cc injectors
built engine/built heads/cams
haltech

in case anyone was curious the setup.

 

thanks for the info guys. charles, lmk when everything is ready and i can swing by!

 

correct. stock fuel system have 3 dampers as well.

Space is so cramped, I doubt I will ever pull out that Marren to fully check. I do know that the marren alone wasnt enough.

 

I had symptoms almost identical to Binder's.
I rigged up my own three damper system (one new one on passenger rail) to the rear of OEM rails and my issues seem~98% resolved. But if the new CJM rails can resolve the issue same or better , I think they would be a much cleaner installation than my one-off hack.

Thanks for the info.

 

We hope that they would accomplish the task on their own. We placed them in the same location you will find them on HR and VHR (370z) Rails. Given, as mentioned already, these cars have a 3rd one from the factory. The 3rd one is always integrated into the stock rail feed softline that comes off the front of the hardpipe.

So hopefully the two are all thats needed. Strangely enough, we have somewhere between 30-40 sets out there maybe more, but we havent received any immediate direct feedback. But I am hoping the two dampers will settle it, or at least well enough to eliminate any noticable bucking etc, since so many cars have not needed any at all.

For me... my own 350z went years without any issues not having dampers, and then at some point I cannot pinpoint in time, it just started having the bucking issues. Anyone else get away without dampers for years then suddenly need them later?

 

WRT

"The 3rd one is always integrated into the stock rail feed softline that comes off the front of the hardpipe."

Yes I still use this one, though it's placement is just kind of silly.

For no extra cost on the DEs , the OEM could have simply placed that third feeder/damper directly onto the rear of the passenger side rail. Why they placed it all the way up top like that just eludes me.

 

Actually yes, come to think of it, I can only recall 2 being on the DEs... there is the one on the back of the drivers rail, and the one on the end of the softline we are mentioning. Your right, the fitting on the back of the passenger rail doesnt have a damper... so the DEs only have the 2. HR and VHRs have 3... one on the softline and one on each rail coming off the bore. The HR ones at towards the end, the VHR ones are in the middle like our damper rails.

 

as soon as the fuel system gets installed and everything put back together i'll let you know my experience charles. unfortunately it wont be a 'direct' comparison since i'm upgrading from a modified stock fuel system...so i'm not sure that it would matter much to you.

 

^^ Btw I tried texting you a little bit ago! I got that system ready for pickup

 

Curious if Nissan does this from the factory more for noise reasons or for tuning. I have no dampers on my setup and have no lean spots, but it sounds like diesel clatter inside the car. There were damper failures on the DE's that caused a service bulletin for the noise, I wonder if the 3rd one on HR's was more of a 'backup' to the original 2 to keep cars out of the service bay, rather than functionally needed.

 

^ Could it just be the injector noise you are hearing? My 370z is running a stock fuel system with Aeromotive pump and ID1000 injectors... and boy can I hear those injectors from inside the car.... unless its the VVEL system noise im hearing. My HKS 1000s in my 350z were loud as hell though... but then again I didnt have dampers in the car then, so maybe thats what I was hearing. Well either way I know that large injectors are noisier lol.

 

No, it's definately resonance in the fuel system coming into the cabin.. the injectors themselves are not very noisy. Mainly from the regulator itself thru the firewall, but also from the entire hard line you can hear it in the floor. Was the same with 440cc and 600cc. Since I have such a quiet exhaust it's probably more an issue for me than others.

 

I should have some before/after data within the next 30 days (sorry for the delay Charles)

 

gotcha... ya i havent personally noticed that in my cars, but my cars also have a very loud exhaust and i dont hear a whole lot other than what i have believed was injector tick.