HUGE 6.4L build project complete

[bigrpowr]

I checked on the way home. Boost is hitting 62 psi. Back pressure is hitting 86 psi and my rail pressure is right around 25000K on wide open long pulls. I'm done beating on the truck until we get the waste gate set. I think that's way to far apart for the boost numbers and drive pressure. Hopefully early next month we'll be able to get it back on the dyno for tuning purposes. It'll be the same one we dynoed on last weekend so it'll be interesting to see how much we pick up from just getting the gate set right.

at over 800 , I was at 64/72, for a reference.

 

[dmkolb]

Was that the closest you could get it?

 

[bigrpowr]

Was that the closest you could get it?

as far as I remember , much less than 10psi differential hurt spooling characteristics . my pistons made it about 100 miles making long hard pulls at this level. I did get pulled over for 140 in a 45 , and he let me go on grounds I was too stupid to learn from a ticket.

 

[dmkolb]

Wow 145 in one of these trucks? Holy ****. 10 psi hurts spooling. Hmmm. I'll pass that on to my buddy when we set the gate.

 

[forcefed6.4ford]

as far as I remember , much less than 10psi differential hurt spooling characteristics . my pistons made it about 100 miles making long hard pulls at this level. I did get pulled over for 140 in a 45 , and he let me go on grounds I was too stupid to learn from a ticket.

You must teach me the ways of your people.

 

[madman1234509]

Got ya, so is the 62psi of boost coming from your water meth sensor? I think your back pressure sensor is maxed out. Your boost definitely is around that level as well.

 

[bigrpowr]

You must teach me the ways of your people.

the guy said at 100 , I never saw him behind me, I was walking him bad. thank god I had my laptop hooked up , I was literally testing boost/bp number at high rpm in overdrive in the silver ecsb . he did ask me to pop the hood to see what made that ungodly noise and high rate of speed. he also mentioned that if he ever saw the truck over the speed limit by 1mph in town that he would arrest me. point was taken . i'm pretty sure because I was flat honest about why I was doing what I was doing he figured I wasn't a complete idiot. needless to say he got more respect and cooperative response from me than any cop who had ever given me a ticket ever. don't think he knows what my 13' looks like thank god.

 

[B585Ford]

I'm usingmy Dashdaq to monitor drive pressure and rail pressure. I have seen rail pressure higher as it spiked to over 25K and then came down to around 24950 somewhere. Not sure what the max is for the sensor monitoring drive pressure. I can monitor boost pressure from my water/ meth controller as it has it's own sensor which reads higher than the stock sensor the dashdaq reads from.

If you are monitoring with a DD, you maxed out your EBP sensor....factory maxes at 86-87....I can't remember for sure, but I thought you stuck with the factory up pipes. If so, I would definitely upgrade while you are puttin in the gate...and I definitely would hold on spray until you are gated.

 

[jdgleason]

86.7 I believe is the max for the factory Bp sensor.

 

[bigrpowr]

86.7 I believe is the max for the factory Bp sensor.

I don't think he is remembering to subtract barometric which is 14.xx for most of us.

 

[dmkolb]

I don't think he is remembering to subtract barometric which is 14.xx for most of us.

I'm not subtracting 14 from the number so am I close to 72? which would put me into that 10 PSI sweet spot you were talking about.

Also for who was talking about when I gate it, it's all ready got the gate installed. Now it just needs to be fine tuned. I'm not going to worry about the uppipes unless they break or leak. After HARD drag strip pulls, and some dyno runs they are still fine so I'm not gonna change what aint broke. I'm also out of cash due to the build so more parts right now isn't an option. I have more into this truck than most people have in their house. It's freakin retarded.

 

[dmkolb]

So I know I'm monitoring the right thing I'm watching sensor "Exhaust Back Pressure Absolute". Is that the one I should be watching?

 

[bigrpowr]

So I know I'm monitoring the right thing I'm watching sensor "Exhaust Back Pressure Absolute". Is that the one I should be watching?

absolute will be the reading that does not subtract for current barometric pressure. are you monitoring on a dashdaq ?

 

[dmkolb]

There is an option right under that one for Exhaust Back Pressure Desired. Would this automatically subtract the 14? Yes monitoring it on the Dashdaq.

 

[madman1234509]

Back pressure desired is what the computer is looking to make. Actual is what the sensor is reading. If you are monitoring with the dash daq turn the key on, but engine off. The reading on your actual back pressure will show you what it's reading as your barometric pressure. Then use that number to subtract from what it's reading when you're driving the truck to get your actual

 

[madman1234509]

But like mentioned before. Before you do any tuning, it may be beneficial to get a 100lb back pressure back on there to rune the gate properly. With your sensor maxed out you have no idea what your starting point is and will just be making blind adjustments. Even if you just buy a gauge a zip tie it to your windshield wiper for some test runs.

 

[sootie]

I'm not subtracting 14 from the number so am I close to 72? which would put me into that 10 PSI sweet spot you were talking about.

Also for who was talking about when I gate it, it's all ready got the gate installed. Now it just needs to be fine tuned. I'm not going to worry about the uppipes unless they break or leak. After HARD drag strip pulls, and some dyno runs they are still fine so I'm not gonna change what aint broke. I'm also out of cash due to the build so more parts right now isn't an option. I have more into this truck than most people have in their house. It's freakin retarded.

72 is maxing out the stock sensor.

upipes are a great investment because at those bp levels and heat cycles they will in fact fail in short order. heck-they fail on stock trucks. dont risk fumigating your passengers or lighting the firewall insulation in fire or melting your engine due to excessive egts...

 

[dmkolb]

I messed with my waste gate adjustment on the way home. We put it inside the cab so it's pretty easy to adjust from the drivers seat. I tried to data log on my Dashdaq but all I got where lines and it wouldn't show me any numbers. Figures. I was able to watch my back pressure which instead of the 86 I was used to seeing was at 77 and this is before subtracting the 14 so that puts me at 63 psi for back pressure. Now I was seeing 62 to 63 psi of boost on my water meth controller. That has now dropped to around 54. Is there going to be a large drop in boost when the back pressure numbers start to come down? If I'm making less boost does this translate into less power?

 

[johnp115]

I messed with my waste gate adjustment on the way home. We put it inside the cab so it's pretty easy to adjust from the drivers seat. I tried to data log on my Dashdaq but all I got where lines and it wouldn't show me any numbers. Figures. I was able to watch my back pressure which instead of the 86 I was used to seeing was at 77 and this is before subtracting the 14 so that puts me at 63 psi for back pressure. Now I was seeing 62 to 63 psi of boost on my water meth controller. That has now dropped to around 54. Is there going to be a large drop in boost when the back pressure numbers start to come down? If I'm making less boost does this translate into less power?

Im not sure on where the limit of boost is on the 6.4 and the specifics of your build but you can only fit so much air into the heads.. So say if 45PSI was all the heads could take/flow, then at 60PSI you are just back tracking the air and BP will go up.

 

[madman1234509]

The way your gate is set up, the more you bypass and limit back pressure, the more you limit boost because you aren't driving the turbos with the exhaust (aka your back pressure) and you are dumping it to the Downpipe or atmosphere. You only need as much boost as it takes to clean up your fuel at WOT. If you have smoke at WOT then you need more air to burn that access fuel to maximize your power potential. If you're not burning the fuel your not using all of the potential energy. Honestly if you were making 62lbs of boost and a total of 86lbs ebp, which after subtracting 14.7 is only 71.3lbs, then you were probably in good shape to begin with and I'd keep closing the gate back to where you had it bit by bit, until you either see no smoke at all, or get back to where you were. My concern was that at 86lbs on the DashDaq the sensor is maxed, and there is no telling what the reading actually was, 86 or 106. But if it came down that easy then you were probably in good shape to begin with. 62lbs boost and 72ebp is nothing to complain about. That's not too far off from what I see right now.