I have 150,000mile 1999 24 valve. I purchased in december and first thing i checked was lift pump, it was bad 0psi. I didn't know any better so I went to auto parts store and purchased a factory replacement one shaped different but worked. Now today was first time to put fuel and boost on truck and it shows 17-18 at idle and with cruising 2-3psi boost I am getting 15psi fuel. I laid into it in third gear and made 16psi boost and my fuel pressure went to about 8psi and jumped up as soon as i let off. Is this what everyone else is seeing? How about boost is 16psi top of third unloaded about all stock will do? Thanks guys. CD

Usually we see a 2-3 psi drop for fuel pressure when you romp on it. Using a stock pump like you are would account for the excessive drop. Smaller fuel lines and weaker pump. Start saving for a FASS, AirDog, or Raptor! Your life will be better if you do! IMOP

Would adding a big line kit help with the stock lift pump?

Stock I saw 18-19 PSI boost pressure WOT... Edge Comp 5x5 and RV275 I see 34 PSI... But tip the Pyro at 1,450 to 1,500*F WOT at 100 MPH...

You need a Big Line kit... 8 PSI is way to low!

I have 150,000mile 1999 24 valve. I purchased in december and first thing i checked was lift pump, it was bad 0psi. I didn't know any better so I went to auto parts store and purchased a factory replacement one shaped different but worked. Now today was first time to put fuel and boost on truck and it shows 17-18 at idle and with cruising 2-3psi boost I am getting 15psi fuel. I laid into it in third gear and made 16psi boost and my fuel pressure went to about 8psi and jumped up as soon as i let off. Is this what everyone else is seeing? How about boost is 16psi top of third unloaded about all stock will do? Thanks guys. CD

Is the turbo a hy or a hx 35??If it is a hx you can get a little more boost with a different brass elbo.I dont know if the hy can be helped.I dont know much about turbos.What do you want out of your truck.

Stock I saw 18-19 PSI boost pressure WOT... Edge Comp 5x5 and RV275 I see 34 PSI... But tip the Pyro at 1,450 to 1,500*F WOT at 100 MPH...

You need a Big Line kit... 8 PSI is way to low!

Mike you think a big line kit would help my pressure stay up? Can I use factory filter etc or do I have to have after market pump etc... Big line kit kinda cheap isn't it? Thanks chris

---------- Post added at 07:37 PM ---------- Previous post was at 07:34 PM ----------

Is the turbo a hy or a hx 35.If it is a hx you can get a little more boost with a different brass elbo.I dont know if the hy can be helped.I dont know much about turbos.What do you want out of your truck.

How do I tell what turbo mine is? Its a five speed transmission so I figure it has different ex housing from what I have heard. I want to just get truck realiable, I have fixed all oil leaks, done kdp mod, changed lift pump, put lift pump realy mod on, have it on 2stroke diet, can see putting new tires on, clutch, big line kit, muffler, and a programmer or injectors of some sort in future. Trying to do it right. Thanks CD

Mike you think a big line kit would help my pressure stay up? Can I use factory filter etc or do I have to have after market pump etc... Big line kit kinda cheap isn't it? Thanks chris

This is what I ran for nearly 2 years... 15 PSI at idle and 13 at WOT. I would condemn a pump at 11 PSI...

http://forum.mopar1973man.com/attachment.php?attachmentid=181

---------- Post added at 07:37 PM ---------- Previous post was at 07:34 PM ----------

How do I tell what turbo mine is? Its a five speed transmission so I figure it has different ex housing from what I have heard.

HX35... 12cm exhaust housing in my memory serves me right... The Auto's are a HY35 with a 9cm exhaust housing...

I want to just get truck realiable, I have fixed all oil leaks, done kdp mod, changed lift pump, put lift pump realy mod on, have it on 2stroke diet, can see putting new tires on, clutch, big line kit, muffler, and a programmer or injectors of some sort in future. Trying to do it right. Thanks CD

A set of RV275 are worth it...

Mike you think a big line kit would help my pressure stay up? Can I use factory filter etc or do I have to have after market pump etc... Big line kit kinda cheap isn't it? Thanks chris

---------- Post added at 07:37 PM ---------- Previous post was at 07:34 PM ----------

How do I tell what turbo mine is? Its a five speed transmission so I figure it has different ex housing from what I have heard. I want to just get truck realiable, I have fixed all oil leaks, done kdp mod, changed lift pump, put lift pump realy mod on, have it on 2stroke diet, can see putting new tires on, clutch, big line kit, muffler, and a programmer or injectors of some sort in future. Trying to do it right. Thanks CD

The hy has a pipe.The hx has a rubber hose with brass elbo on cold side.

Is the turbo a hy or a hx 35??If it is a hx you can get a little more boost with a different brass elbo.I dont know if the hy can be helped.I dont know much about turbos.What do you want out of your truck.

So I must have the hy because I have an auto so does that mean I'm hooped for getting more boost when the time comes or what can I do:shrug:

So I must have the hy because I have an auto so does that mean I'm hooped for getting more boost when the time comes or what can I do:shrug:

I have a old hx 40.I will take a picture of what i am talking about.I dont think the auto makes a difference.I could be wrong.As you look at the front of the turbo if there is a tube instead of a hose ,i dont know how to "trick" that turbo into more boost.Maybe someone here can chime in and help us both learn more.Maybe there is a way?Now with a factory setup over lets say 45 lbs of boost can be flirting with disaster.You dont want to blow a head gasket .Mine let go around 55 lbs.Some will take more ,some less.You can still have fun at 35/40lbs.

Stock I saw 18-19 PSI boost pressure WOT... Edge Comp 5x5 and RV275 I see 34 PSI... But tip the Pyro at 1,450 to 1,500*F WOT at 100 MPH...

You need a Big Line kit... 8 PSI is way to low!

Mike,

I am getting no where near as much boost as you are. Would love to see in the 30's and believe that the highest I have seen is the high teens or early 20's.

Suggestions for this? Am I looking at a new/oh turbo? Truck has 120k on it and runs great.

Thx,

Joe A

Mike, I am getting no where near as much boost as you are. Would love to see in the 30's and believe that the highest I have seen is the high teens or early 20's. Suggestions for this? Am I looking at a new/oh turbo? Truck has 120k on it and runs great. Thx, Joe A

Are you running a boost elbow in unison with your Edge? Or some type of turbo waste gate control to allow the boost to exceed 20 psi?

Sorry for the delay, did not see this reply.As far as I know, except for the "jake brake" the truck is stock. I added an Edge w/attitude but do not have the VP-44 wire hooked up so its at range 1 with no extras. Have not seen anything amiss with the turbo tubing but have no reason to believe that the turbo is not the original one, so 120k is a lot of miles for a turbo. Joe

Shoot... a Turbo will last a very long time if you take care of it... I've got a 170K miles on mine... I'm sure there is other people that will chime in with more miles.. As for the VP44 if you going to tap it I would opt for the stealth plate...

Mike,Thanks for the suggestion. For now I am just real happy that its running nicely and reliable. What I would love to do is put an overdrive unit of some sort on it to get the rpm's down to reasonable at 75 mph, but having to save money for that for now. Joe

(Shaking head) You should actually reduce you speed more than chasing a over drive gear unit... Vertical number is required HP. Horizonal number is road speed. Colored lines is drag coeffiency. Typical stock truck without oversize tires and no lift is about 0.48 in drag. Now look at the curve as you increase speed the wind drag grows exponentially. Now if you got a leveling kit or lift kit the drag co. will rise so will oversize tires.

Though speed is a big factor, I am not so sure that RPM doesn't play a role also. I run 2050RPM at 70mph, that gets me right at 21mpg, but I think a lower RPM around 1800 could yield higher results. It's the same factor between 4.10 and 3.54 trucks. Even if the 4.10 does make the engine have an easier job, it still uses more fuel to turn the higher RPM, this has been proven by people over and over who constantly say they top out at like 18mpg. From what I have tested and found out, 5mph=2mpg on average, this relationship is exactly the same curve as what Mike just posted, where HP could be replaced with MPG. I was getting more than 2mpg drop as I got around 70 then 75, but down around 55-50mph, I was getting 1.5mpg drop. When you start slowing down, wind becomes less of a factor, so your mileage drop isn't as big, as you speed up, wind starts getting really hard to push and can bring your numbers way down as you speed way up.

(Shaking head) You should actually reduce you speed more than chasing a over drive gear unit... [ATTACH=CONFIG]1261[/ATTACH] Vertical number is required HP. Horizonal number is road speed. Colored lines is drag coeffiency. Typical stock truck without oversize tires and no lift is about 0.48 in drag. Now look at the curve as you increase speed the wind drag grows exponentially. Now if you got a leveling kit or lift kit the drag co. will rise so will oversize tires.

In flight school, it is taught that as your airspeed doubles, the drag is squared. These trucks have a max. optimum speed of about 45 mph. Frome there the fuel economy and coefficient of drag drops like a Simmonized piano. My fuel economy drops from around 23 to 24 mpg at 45 mph to about 13 to 14 mpg at 75 to 80 mph. You mileage may vary......just sayin'.

I have to say you guys are right on. My 410 truck gets it's best mpg... in the 18s... at 45 or so. I run highway at 55-60, just under 2000 rpm and the mileage is decent. It'll run 65 but the mpgs drop off. All this is lightly loaded. Russ

Thanks guys, and guess I will just stick with driving at 60-65 then!My truck seems to get best mileage around 1600 rpm, and once I get too close to 2000 area it falls down. Joe

Thanks guys, and guess I will just stick with driving at 60-65 then! My truck seems to get best mileage around 1600 rpm, and once I get too close to 2000 area it falls down. Joe

same with my truck. i typically am the slowest driver on the turnpike. i try to stay above 60 for safety, as the posted speedlimit is 75 and most do 80