| I've now verified by replacing the fuel filter with a Nissan stock filter and my fuel pressure is working exactly as it should. Full boost at high rpms feels good again (it's been so long!) I sent the following email to K&N and will keep everybody informed if they respond (if you care LOL)
Hi,I have been using a billet filter for about 2 years. I drive a low mileage 1993 300ZX TT which is highly modified. About a year ago, I blew the original engine (only 35,000 miles) by shattering the ring lands on the #6 piston which is notoriously hot, especially when running bigger turbos and higher boost. After replacement with a brand new short block and some dyno testing we discovered that my fuel mixture ran very lean on the top end after about 5500rpms on 18 pounds of boost. After putting a fuel pressure gauge on the car the fuel pressure would rise up and then drop off to stabilize around 50psi. On this car, 43.4psi is reference pressure and should rise 1:1 with manifold so at 18psi manifold the fuel system should be 61psi. It would spike to 61 and then drop to 50, thus causing my lean condition. If I ran lower boost that caused proper fuel pressure to be at or less than 50psi, it perform properly. After checking that the filter was clean I went through every diagnostic including replacing the fuel pump itself, replacing the stock regulator with an Aeromotive, bypassing the stock damper, and FINALLY bypassing the fuel filter. Lo and behold, when I bypassed the filter, my pressure would hold peak perfectly under high boost. As of today, I have pulled the K&N and replaced it with a $10 Nissan stock fuel filter and my problem is now solved. Obviously I am more than disappointed in the performance of this filter and can only surmise that I had this lean condition caused by the filter when I blew my original engine. Upon posting my results to our online community two other individuals indicated they have had the same troubles in the past. I was curious what any official response might be and wanted to let you know of the situation. Isn't this filter designed to handle pressure loads in the 60-70psi range? Just to make absolutely sure, I pulled the filter again to check the screens and they are perfectly clean with no visible restrictions. I look forward to your response. Thanks, Greg Fields
Owner/Admin
[ http://www.twinturbo.net ]
Meddle not in the affairs of dragons,
for you are crunchy, and good with mustard.
 |
