My dyno numbers always seem to be much lower than others with the same or very similar combos. I think I might know why. When I bought my truck the previous had already installed a gear vendors over/undrive unit. This unit has to be causing more driveline loss. If its 5% loss through the unit and i should be around 430hp, and I'm only getting 407 that would calculate out very close. I have an e-mail in to GearVendors, hopefully they can tell me what percentage of driveline loss this unit has. Makes since though doesn't it? Stupid thing doesn't even work right now either, makes me want to chuck it.

 

I know you probably don't want to hear this, but that might be the sign of a dying vp44. I know rjohnson was having lower dyno results, and some signs of low boost/power, and it turned out to be his inj. pump. Just a thought to keep in mind, but hopefuly not your problem.

 

Well I spoke to a tech at Gearvendors, and was told that the driveline loss through the unit is less than 1%. I guess my theory is wrong.

dodgediesel4x4, What your saying might be true, but wouldn't there be symptoms of a dying pump? This truck runs fine, never cuts out at high rpm, no hiccups, nothing seems wrong. I'm going to price out a new HotRod VP-44 anyways, and some Mach-4's i think.

 

Neither did rjohnson's. The only thing that tipped him off was the fact that he couldn't build boost while power braking (that and some beer influenced logic ). Took it to the dealer and sure enough had a p0216 code. Replaced the injection pump and went from 441hp to 526hp with no other changes.

 

Neil,
I had very few indications of a bad VP-44. Still don't know how long I lived with it cause I don't check for codes unless I'm having a problem.
Over a two week period I started having very occasional hard starts and some white smoke at startup. Finally got a P1693 companion code.
Gradual power loss snuck up on me and I really did not notice it in daily driving...but had to be over at least 3-4 months.... with no obvious signs of a problem.....till a code finally showed up.

Don't know if this is your situation, but it can happen this way!

RJ

 

can you only see the p0216 code from a dealer scan tool? I have a cheapo AutoZone tool on loan but it doesn't seem to pull any codes.

 

I've heard from others that Autozone can pull up the P0216 with their scanner....if you are showing the P1693 code already.

RJ

 

Damm, Niel I was hoping you were going to 'chuck' your OD unit.... I would have liked you to chuck it MY WAY !!! I was even going to tell you it has a 13% loss too, but I guess I was too late!

I have one of those units on my other truck and I love it !!


And for the record, I feel that my CTD is doing the exact same thing, although I don't have any dyno records. Seat of the pants feel is unchanged, but like rjohnson said, it happens over such a long time you don't notice. I do notice the inability to make any big hot EGT numbers on the higher settings anymore.... I highly doubt that my HX35 is moving that much more air as it 'matures', so I suspect the VP is moving less fuel

KP

 

What kind of dyno? Corrected or uncorrected dyno numbers?

 

Bart, I dyno'd on a Mustang Dyno. I didn't see a correction factor on my printout. No codes are showing up.

 

Hmm. I have P1693 but no other codes.

 

Sorry.......but I believe the P1693 code is a strong indicator that you have a failing VP-44.

Don't know if all Autozones have the same type/quality code testers?

RJ

 

You are ONLY comparing your #'s with other HO's...Right? And only HO's on a Mustang Dyno, right?

RJ

 

Yah, Don't you think my dyno numbers are too low for my setup? How much lower are the readings on a Mustang compared to a Dynojet?

 

I know too little about how HO's react to different bombs to comment on your numbers. Is your HTB2 a 12cm2 or a 14cm2 turbine housing? I believe a 12 would cost you on the dyno.

Regarding Mustang Dynos...I know it depends on whether they "load" (build in resistance) into the dyno or not. It they do not, I believe you will get similar #'s to a Dynojet.

I use a dyno more to measure hp differences over previous set ups, than to look for total number. My last three dynos runs have not produced the same max boost I see on the road....so I take them with a grain of salt!

RJ