what to do next?

[6DoubleDuece]

hello Guys,
I have a 1989 CTD with a powerstroke intercooler, tweaked pump, 4200GSK, 60Lbs valve springs, custom fuel pin, HTT 64/14 turbo, 4" straght pipe's, and a nitrous system.

Here is the deal. I had POD's in the truck and I dyno'd 340 #2 and 417 on N2O. Then I changed to some big injectors (lets just say they hold some records ) then dyno'd again and 356 on #2 and 433 on N2O.

Not what I was expecting, so I figured I would check my fuel pressure. As expected full throttle and 0 psi. I then a holley Blue that I had laying around and now I have 15.5psi @ Idle and 8psi @ ftb

Am I losing TONS of HP with my low fuel pressure? I would like to break 500hp I just don't know where to get the rest


thanks
Brenden

[Begle1]

500 HP with the stock pump has yet to be done; with nitrous you should be able to get there, though.

If you're seeing 0 PSI at full throttle, that could steal a whole bunches of of power.

I would think that you could get to 400 on #2 only if you had a good fuel supply.

[KTA]

If they are ddp injectors they are probably your problem, I know Stomp lost power with his set. what works good with a p-pump isnt necessarily what works good with a ve.

[6DoubleDuece]

nope they are stomp's 370's What do you think about the fuel pressure? Should I just bypass the stock lift pump?

I wonder how much difference it would make?

Thanks
Brenden

[Paccool]

Hey Brendon

Still trying to figure it out huh? I tried several times to get up there but couldn't. I have a set of new Era 435's coming, I'll let you know how they do. If you are going to the race on the 11th you can see for yourself.

[KTA]

If it is your fuel pressure you will notice a lack of smoke at full boost. If you are getting plenty of smoke you may try advancing your timing. I also think you may be having a problem with the stock lift pump or fuel filter restricting you.

[6DoubleDuece]

Stan,
Still trying to get this sqaured away, anytime you want to come by you can look at my old truck


Brian,
Thanks For the help I really appreciate it. I am going grey at full boost, and I was thinking that the 64/14 was doing the trick. I guess I was wrong Probably is fuel supply. As for timing it's a early motor so it's a 1.5 stock and I have it bumped about 3/16".

About the lift pump and filter should I bypass them? What would you do? Maybe a inline filter and bypass the lift pump? Or should I go piston?


Thanks,
Brenden

[wannadiesel]

I built a parallel system on mine, the Walbro feeds into a tapped banjo on the filter head. No less than 15 psi under any conditions.

[6DoubleDuece]

Hey Wanna,

What pump are you using and how many GPH is it? What size line did you use and which banjo bolt? Got Pic's?


Thanks

Brenden

[wannadiesel]

I have a Walbro 391. At the pressure it's running the flow is around 40 GPH. It's plumbed with 3/8" hose, it goes into the dirty side banjo bolt so the it gets filtered by the stock filter.

The secret to maintaining pressure under load is to have a bypass line after the filter with a relief valve. That keeps the pump from "seeing" the restriction of the filter.

There are pics in my DTR gallery.

[bgilbert]

Well the 4200 gov spring will do more harm than good. Put in the proven 3200 (366) spring. Did you trim it to stock gov spring length? What if any throttle linkage mods did you do with this spring?

I am not surprised you didn't gain much with the 370's over POD's. Pod's actually flow more fuel.

Give back those 370's and get a good set of EDM's.

[6DoubleDuece]

Thanks Wanna,
I will Check your gallery. I would like to get the fuel delivery constant just to eleminate it.

bill,
I don't know what your problem was with the 4200 gov spring but it works great in my truck. I ran the 3200 gov spring. I like this one better.

I did modify the spring ends so that it is the same length as the 3200 spring. No other mod's are necessary! It works perfectly.

You know you hear a lot that POD's flow more than 370's but I think the record is what 386 with them What is the record on 370's????? Or for that matter what is the record on a VE with 370's????????? I think the guy who flowed them worked for Lucas!

So bill I think we can rule out the injectors as the problem.


Thanks,
Brenden

[bgilbert]

Well sounds like you got it figured out.