jungles82

Well i hit the dyno again and i went from a set of 50hp ddp's to a set of 5x14's which are custom flowed to a little over 150hp. The problem was that i only gained 13hp and 50ftlbs of torque. This is for the ctd in my sig. So does anyone have any ideas? I still need studs and springs but i don't think it would hold me back that much, Also i was running about 45psi of boost. I had no top end smoke and egt's were only 1200-1300. With my 50hp ddp's i was at 340 850 which was still not that great for what i have so im stumped. Please help thanks. Matt
Low fuel pressure?
181 Dv's?
timing?
injectors out running my lift pump?
Or anything else you can think of.

Wicked500R

What did you do with your DDP 50's ?

Mcmopar

I'd check the fuel supply/pressure first. Have you changed the filter? What is the fuel pressure? The timing could be an issue.

jungles82

i ran 340 850
will do i will change the filter timings at 17.5*

Fueling around

Bigger turbos are really tough to light on a chassis dyno.

jungles82

well i got it spooled great 46psi but no smoke

6speedcowboy

you should be able to do better than that with stock injectors. what you running for a fuel plate? im assuming stock lift pump?

jungles82

A #100. stock lift pump but today i checked fuel pressure and it was 19-20 at idle and 10-15 at wot in OD with TQ locked 41psi boost. So i think i have a lift pump problem what do you guys think? Also with that little of fuel pressure i think my 5x14's are gonna make my egt's out of control till i go to twins.????

DZLPWR

I dont have a solution to your problem, as it seems your headed in the right direction, but i figd id chime in and give the specs on my old truck for a hp/tq benchmark with the mods on the truck. Not saying it was set-up perfect, but a solid example.

1998 12v 215hp, marine 300 inj, banks plate, stock timing, hx35 w/14cm exh housing w/wg, bhaf, 4" exh
349hp/902tq 38psi

Fueling around

You answered your question on fuel delivery. The pressure is marginal at idle and very low with the pedal mashed. A new (stock) lift pump & overflow valve is slightly over $100 these days.

I wasn't impressed with DDP stage 4 injectors. A buddy of mine put a set in his truck and the hp numbers were dismall, plus the injectors slobbered fuel which was confirmed with a bench test. He changed to another brand with much better results.

The local pump builder can get some massive fuel delivery on stock DV's. I have one of his pumps in my truck with a custom plate (set very conservative) that defuels the same at higher rpm as a stock plate and still gives me 300 rwhp.

Big HP differences between stock auto & manual pumps due to the plunger & barrels and governor. Another buddy with a 96 manual hit 400 RWHP on a #10 plate and 5 hole injectors roughly equivalent to the marine 300 which are 4 x 12.

DZLPWR

Oh i see, didnt know there was that much of a difference! Wow

jungles82

Yea i am not a huge fan of ddp's the ones that i have "besides my 50's" are a custom built set by engineered diesel. I think I'm gonna swap-out overflows and see what that does and then go into lift pump im just gonna get rid of the stocker and go with an airdog or fass setup it will unclutter my motor a bit also. Im also being told my a guy that i know that its my lack of 4k gsk and valve springs and delivery valves but im thinking his credibility for 12v knowledge just got bumped down a few notches also he said fuel pressure wasn't that big of an issue i say bs.