okay so this thread is kind of a lead form my other one but i was wondering if there is a performance lift pump for the 12 valve engines, if there are were could i get one. thanks


jason

 

Not sure if it is really a performance pump but some seem to like the Air Dog pumps. Of the pumps I've heard, FASS, Air Dog and RASP seem to be the best liked. RASP info can be found on the DTT web site and uses a little different approach then the FASS or Air Dog.

 

You can tweak your overflow valve for more pressure, I am at 50PSI at idle and can't pull it down past 30PSI at wot. After I install new injectors and a bigger turbo if needed I will install a FASS 150gph. My .02

 

how do i tweek my overflow valve, are you talking about putting a ball point pen spring inside the overflow valve spring, if so i did that, unless maybe i need a stiffer spring. if this isn't what you are talking about then please fill me in on what you did thanks

jason

 

That is probably what he is talking about. I did mine and it is 42 idle and lowest is 20 at WOT. I am about to put a factory 24v lift pump with 1/2" line behind my factory pump. I figure the 24v pump will feed my pump 10psi or so and will take some of the load off of the factory pump. I'll let you know how it turns out. BTW, Infidel has said that anything over 40psi can blow out internal seals of the IP. I think I'm going to follow his advice.

 

All good options there..

But why not Bypass teh LP with one of those haisely auxilary fuel systems if you want more FP? again tho anything over 40 psi is gonna blow the seals in the IP...

Rick

 

Wasn't aware of the Haisely fuel system. Actually I suspect the FASS, Air Dog or RASP can all be set up to bypass/replace the stock lift pump. I've read a few posts which indicate the stock LP can be left in-place and used if the aftermarket LPs fail but don't know for sure how that would work.

One thing that hasn't really been brought out is if a performance lift pump is really needed on a 12V. The perception is the stock is pretty durable even though the LPs on my 97 and daughter's 96 both had to be replaced at about 180K.

My perspective is the fuel pressure and delivery benefits of the aftermarket LPs are the real selling point. Instead, the ability to separate out air from the diesel is more important on the 12vs. I personally haven't pinned any performance issues on low fuel pressure or fuel capacity but have encountered several problems with air leaks in the low pressure fuel system.

 

I am going with a aeromotive a1000 pump and regulator. I have 50 psi at idle and 0 at WOT with my factory setup.

 

well im wondering if i should use a stiffer spring since i only have 22psi tops at idle while others that have done this are making 30-40 psi at idle and some are making more. any thoughts about puttin a stiffer spring in. thanks


jason

 

Normally i just shim the spring. I machined up an assortment of shims. It just takes a minute to drop one in.

 

Besides adding the pen spring you need to stretch out the existing spring. Not a precise adjustment but it works.

 

golly gosh dang, pulled the return valve spring deally again and stretched the springs, im now at 55-60 at idle, don't have wot #'s yet since truck still isn't drivable. but im curious, is 50-60 psi at idle to hard on the lp, should i adjust the springs in the return valve again to make it more like 40-50 psi at idle, thanks



jason

 

Infidel says that anything over 40psi can damage the seals and I trust what he says. I would play with it a bit more and try to get it around 40-45psi.

 

I ran 60PSI for around a month without any problems... I don't reccomend it though. I just adjusted mine to where I have a good pressure at idle and the lift pump doesn't tick (started at 60 and went down from there). I will probably lower it but I don't have a bunch of time now-a-days...

 

hey guys thanks for the input, guess i'll play with it till i get about 40 psi at idle, thanks again

jason