any one have problems with paxton sc

71dusterjon

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just curious as to if anyone who has these superchargers have had problems with fuel delivery/pressure. I have been talking to Dan and my dyno guy and they both believe my lose of 90 hp and 100 ftlbs from when Dan tuned this engine is due to fuel delivery. I ordered two belts from paxton since mine is cracked and talked to another member on here and he said just switching the belt fixed his similar problem.
 
if any thing I am making to much boost. I top out at 10 psi at the upper RPM.I thing the blow off valve needs adjusting
 
one you need to put a fuel pressure guage on it, that is the ONLY way you can tell if the fuel system is up to par.

also you really need two more guages, one is a must.

you absolutely need an air/fuel guage(lets you know when you are running rich or lean)

the other a boost guage.(lets you know how much you are putting out, and when it changes from an average you know there is a problem)

with these three guages you can tell just about whatever you need on your supercharger by looking at them, they are critical guages on a set up like yours.

but you can also check your belt to see if its slipping by taking a piece of chalk , mark the belt and a pulley at the same place, run it up in the rpms,,comeback, an check to make sure the marks are still in the same place, if not the belt is slipping, a cracked belt has nothing to do with performance, most of the time a month later a new belt can have cracks in it
 
for the boost gauge would i need one with vacuum or just a boost gauge? for the fuel pressure Dan said fuel pressure can be 55 psi at idle then 100psi at peak power so i need one that goes to 100 psi? Thank you guys for getting on the right track. i still have a lot to learn about this truck especially since its my first forced induction engine.
 
you should get others chiming in to help bud, but I like a manual vaccum guage, I like the true time readings, on the fuel pressure , yes you will prob need on to around 100 psi, but maybe I am wrong, but even boosted you should stay withing ten pounds of your set fuel psi?
 
this is if your running the stock fuel kit setup from paxton's novi kit,

the fuel pressure is at 60 psi below 1 pound of vacuum, between 1 pound of vacuum and 1 positive pounds of boost the first pump kicks in and it should be around 80 psi, above 1 lb of boost the second pump kicks in and it should be no less than 100 psi. mine runs around I would guess to be 110 PSI. the gauge only reads to 100 PSI. this is how it is in my truck anyway. I have a vacuum/boost gauge, AEM wideband, and a 100 PSI fuel pressure gauge. I also monitor the air temp post intercooler with an older autometer IAT gauge.
 
dang! didnt think they ran that high? heck I made 1000rwhp on 60lbs and that was at max?

well there is a ton of difference too I didnt think aobut the paxton runs that boosta pumpin deal dont it"? my bad:eek:

cant help it , I;m old school , still like my one bigol pump that if I stick it in a water bucket i can hit the neighbors a couple houses down:D
 
interesting. my dyno guy said that the reason i was running low afr and for my strange power curve was due to my secondary fuel pump. im waiting to here back from dyno guy to see when i can get in and have him tune my engine and see what's going on. then afterwards i'll be getting gauges.
 
71dusterjon said:
interesting. my dyno guy said that the reason i was running low afr and for my strange power curve was due to my secondary fuel pump. im waiting to here back from dyno guy to see when i can get in and have him tune my engine and see what's going on. then afterwards i'll be getting gauges.
may be bud, i am not a fan of multiple pumps, too many parts to fail or not work properly, i like jsut one big pro series pump, and your good for 2000hp, plus it just looks cool:D
 
me either Stink, as soon as I get a decent tuner figured out, most likely DC performance, I am going to can the pump setup and go with larger injectors and a SCT tuner.

stink, the way Paxton did it is a fairly simple set up an works well if you don't go crazy with other mods, I on the other hand will sooner or later, more likely sooner. the increased pressure is paxton's way of cheating not putting larger injectors in. I think I've heard that increasing the pressure to 100+ PSI is equivelent to a 60 lb injector. and I would assume at the time of release of the novi kit the split second timer with the 2 pumps were a cheap and effective alternative to a VEC II or VEC III, now I would imagine an SCT with new injectors would be a close cost to the pumps and split second timer setup. I doubt Paxton would spend the time and money to research that though since they have a proven kit already.
 
mr. anderson said:
and I would assume at the time of release of the novi kit the split second timer with the 2 pumps were a cheap and effective alternative to a VEC II or VEC III, now I would imagine an SCT with new injectors would be a close cost to the pumps and split second timer setup. I doubt Paxton would spend the time and money to research that though since they have a proven kit already.
thats it right there bud, I dont think as long as you dont push the envelope its a bad set up, and a very enexpensive way also, which is the only way a manufacturer can make money, it works, and works well, LOOLOl even me and fstjack have had REALLY heated discussions over this, but I still am a one pump man:D by jingys if it goes out, your stopped, if ya got a couple pumps and one goes out............wellllllll:p
of course alot will say you can put a switch here, a relay there an so forth, but what is that? more things to go wrong:p

dont get me wrong , a ton of tuners go that route and have a ton of success, underground beign one of em, but eh, its just me I guess:p

but yeah bo, I can get the single pump for ya, but really , trust your tuner, he is the man that has your nutts in his hands;)

you need to have ultimate trust in him:rock: listen closely to him , and bet my bottom dollar he will most likley say that some of what I say is BS:p but thats his way of getting his point accross and his way of doing things,

but what you must do is relax, sit back , take notes, do research, take it alllll in, sit down, and make your own decisions, in the end it is your truck , and like all of us you will make a mistake or two, but its all fixable.

And dont for petes sake take my word for gold, its jsut the way I do things, which most on here will tell ya, is usually a little out of the ordinary from others:p but I will try my best not to steer you wrong, if I dont know, I'll tell you I'm stupid:D
 
haha thats some good advice. from the sounds of it i think the two pump system will be fine for me since everything i wanted to do to this truck is already done and i dont plan on doing any rebuilds of the engine to make more power. Still not sure what the true problem is, this is just a guess from dan and my tuner based on my recent dyno pull.

stinker when you said mark the belt and pulley with chalk wouldn't the belt not line up again after several revolutions?
 
I have a few questions.

Was it a mustang Dyno or Dynojet on the last pull?
Have you checked your spark plugs for fouling or detonation?

I also agree with Stinker on the Gauges... these will help you trouble shoot any problems you may have.

Again, I'm no expert and I would take the advice from Dan at DC performance over mine any day. In my uneducated mind I think that the fuel pumps are working fine if your running rich. If a pump would fail it would lean out. The split second box switches to open loop at WOT. So, at any given RPM it will provide a set amount of fuel based on RPM's. If the boost is not where it should be it will run rich. There is also an IAT Mod you could try if the ECU is pulling too much timing when hot. http://www.vtcoa.com/forums/showthread.php?t=24109
 
heres the link to the dyno they use
http://dyno-comp.com/tuning.php

I was thinking the same thing that if my afr was 10 then that would lead me to believe both pumps are working correctly. Dan thought maybe i should change the mechanical discs in the fmu to lean out the afr.

I'll check my spark plugs tomorrow. could just my timing and afr cause this amount of power loss?
 
tsmith3 said:
I have a few questions.

Was it a mustang Dyno or Dynojet on the last pull?
Have you checked your spark plugs for fouling or detonation?

I also agree with Stinker on the Gauges... these will help you trouble shoot any problems you may have.

Again, I'm no expert and I would take the advice from Dan at DC performance over mine any day. In my uneducated mind I think that the fuel pumps are working fine if your running rich. If a pump would fail it would lean out. The split second box switches to open loop at WOT. So, at any given RPM it will provide a set amount of fuel based on RPM's. If the boost is not where it should be it will run rich. There is also an IAT Mod you could try if the ECU is pulling too much timing when hot. http://www.vtcoa.com/forums/showthread.php?t=24109
see, I knew someone with brains would come along:D

didnt even pay attention that you were talking dan at DC, listen to him bud, he is very good on the paxtons:rock: and chris is a top notch tuner bud:rock: , your truck IS in good hands:congrats: :congrats: :congrats:

:dontknow: tsmith3 eats boogers tho:D
 
Stinker said:
see, I knew someone with brains would come along:D

didnt even pay attention that you were talking dan at DC, listen to him bud, he is very good on the paxtons:rock: and chris is a top notch tuner bud:rock: , your truck IS in good hands:congrats: :congrats: :congrats:

:dontknow: tsmith3 eats boogers tho:D


What I do with my own boogers is my business. :p

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