6.7 Fuel Rail Pressure Drop with Hot Tunes

Dan · Feb 22, 2014

BK39 said:
Do you guys take a little out on the tuning end because of the FRP drop? To prevent that from happening?

As Zane said, "dyno results, other's may vary". It's wild to think they vary 75RWHP. I've seen ppl claim 520-550RWHP.

http://powerstrokearmy.com/forums/showthread.php?t=41501&page=7

Im under the impression these claims that the stock cp4 is worth up to 550 hp is with an upgraded turbo... Since it's the turbo that is only worth 480 hp ish....

dseitler · Feb 23, 2014

I'll let you know. I ordered Rudy's Modified VCV should have it installed Wednesday. My rail pressure drops to mid 26K. I'm at 483HP now and will see Friday night at Palm Beach Raceway test & tune if I can maintain rail pressure in the 1/4. I'll post it here.

BK39 · Mar 4, 2014

dseitler said:
I'll let you know. I ordered Rudy's Modified VCV should have it installed Wednesday. My rail pressure drops to mid 26K. I'm at 483HP now and will see Friday night at Palm Beach Raceway test & tune if I can maintain rail pressure in the 1/4. I'll post it here.

How did this turn out?

I just ordered the SPE tunes, the itch for more power is starting to get to me.

dseitler · Mar 4, 2014

The valve is still on back order. I found out Rudy's in getting them from Elite Diesel. I talked to them today and it still is on back order and has not shipped. I'll post it here as soon as I get it installed.

mattmal9 · Mar 4, 2014

dseitler said:
I'll let you know. I ordered Rudy's Modified VCV should have it installed Wednesday. My rail pressure drops to mid 26K. I'm at 483HP now and will see Friday night at Palm Beach Raceway test & tune if I can maintain rail pressure in the 1/4. I'll post it here.

Slightly off topic but I noticed you said you were at 483hp. Is that number from a dyno or calculations? Just curious to know what your truck is making as in torque. I have a 2011 350 with the same mods minus the intake tube and the SPE tune(considering to order).

dseitler · Mar 4, 2014

Trap 1/4 mile speed with the weight of my truck being at 8580. It's real close if you talk to the guys at SPE and H&S. I know I need to go to dual fuel pumps to maintain 29500. I ordered the truck the last day you could order a 13 knowing I could take full advantage of rebates and special financing. I'm just not willing to go that far yet but I know I will someday. Only had the truck 7 months. I spent insane stupid money on my 06 6.0 to get into the 12 second cat. I want to go 10 HP under rod bending power and I will be happy. Just have to find the right balance and the right smart money path to get there. Also need the find the right HP number to be safe.

dseitler · Mar 4, 2014

As for the H&S Tube, I like it and glad I have it. I popped the plastic one 3 days after I did my delete. I wish I could find the Y pipe after the cooler and scrap the plastic intake. Hook my S&B directly to the turbo. I am sure that plastic/aluminum intake is robbing me of power and air.

Default15405 · Mar 5, 2014

dseitler said:
As for the H&S Tube, I like it and glad I have it. I popped the plastic one 3 days after I did my delete. I wish I could find the Y pipe after the cooler and scrap the plastic intake. Hook my S&B directly to the turbo. I am sure that plastic/aluminum intake is robbing me of power and air.

ive been looking to do the same thing because it has to be robbing some power. I even posted a thread on here and at the nation asking about that and no one responded, emailed elite and spe for potential custom made pipes and no response from them either. I saw elite sells the intake plenum adapters to make your own, but to get rid of the actual lower intake runner you would have to have piping fit the wide oval of your intake plus the two different sized (and one oval) turbo inlets. im sure you could figure a way to bypass the intake runner, fill in the turbo muffler inlets, and have it flow better, but it still leaves the ugly lower intake runner there with two massive holes just sitting there. for me though it needs to be functional and pretty.

dseitler · Mar 6, 2014

Elite sells the intake pipes I found out today. They have the Y pipe from the cooler to the intake along with the turbo output to cooler. In the kit it also has the pipe from the intake to the inlet on the turbo. We would have to modify the connection at what ever intake filter set up we are using. The kit sells for 1100.00. They don't have any pictures of it online but I did see a picture of piping on there Facebook page. Don't know if it would be the same.

SAK · Mar 6, 2014

There is a lot on the design stages that will replace the upper and lower intake manifold. But it will be a long while before it is avaliable.

dseitler · Mar 6, 2014

I started this thread with the hopes that the members who have tried the modified VCV's or other mods would give there input. I see on other threads where people say they have purchased mods but then never post any results or opinions on the performance. Same thing with the Wicked Wheel thread. Purchased but then no results or numbers of any kind after the install. I think there has to be a ton of us who have done the deletes and installed the custom tunes but are dropping rail pressure. I was looking for other avenues before going to the dual fuel pumps at 3K. Has anyone tried the modified CP4 pumps?

RedRice589 · Mar 7, 2014

dseitler said:
I started this thread with the hopes that the members who have tried the modified VCV's or other mods would give there input. I see on other threads where people say they have purchased mods but then never post any results or opinions on the performance. Same thing with the Wicked Wheel thread. Purchased but then no results or numbers of any kind after the install. I think there has to be a ton of us who have done the deletes and installed the custom tunes but are dropping rail pressure. I was looking for other avenues before going to the dual fuel pumps at 3K. Has anyone tried the modified CP4 pumps?

It seems the easiest thing for us to do is dual fuelers. Idk not too many guys are even rolling with modified 6.7's I'm waiting still. Mines just fine as it is but I can't go to the track or anywhere so I'm content for now.

Also it seems after so many 6.4 money pits guys are really happy with how nice they are off the lot.

dseitler · Mar 30, 2014

Does anyone know the location of the sensor that throws the P0093 code? The P0093 code is for fuel system leak detected. Large leak.

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drunk on diesel · Mar 30, 2014

more than likely it's a calculation that trips the code

swinky · Mar 30, 2014

Can't help you on your problem but I'll hit you up next time I'm on leave. I'm from loxahatchee, old 6.0 has made many passes there.

Where are you getting your weight from? That sounds extremely heavy.

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dseitler · Mar 30, 2014

Yeah I was surprised too. The 575 truckstop down in Fort Lauderdale Florida. The CAT certified scale.

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dseitler · Mar 30, 2014

It's getting annoying. When I pull my boat and drop down to the street tune if I get on it it will throw the code shut off. It won't do it at the track only if I go past the quarter-mile and stretch it out it will throw the code and shut down.

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SAK · Mar 30, 2014

dseitler said:
It's getting annoying. When I pull my boat and drop down to the street tune if I get on it it will throw the code shut off. It won't do it at the track only if I go past the quarter-mile and stretch it out it will throw the code and shut down.

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What tunes are you running?

drunk on diesel · Mar 30, 2014

looks like an SPE tune

have you tried running the canned H&S tune to see if the problem is still there? maybe the SPE tune is commanding too much rail?

dseitler · Mar 30, 2014

SPE with MP8. I really like the set up and don't want to give up the power or times. I downloaded the schematics from Mitchell but it does not specifically say which sensor will do that. My theory is if it's the VCV then I have to go dual fuel. If it's the one that we all see by the fuel filter than its supply pump. I have ordered a Turbo upgrade from SPE I want to do that first from talking to the members on other threads. For some reason the 11's and 12's don't have this problem. I'm willing to do the testing at my shop just looking for input in direction.