pulse width questions?

[mudygmc]

I have a 68 cheetah 40%over nozzles and an 85%over cp3. In my tune I am running 40-42psi boost and a max pulse width of 2725ms. I have logged the tune on the street and pulling. It shows the demanded psi at 271xx and the most I have logged is 26107. Is this the max psi my cp3 will put out or is there something I need to change in the tune. It still blows a moderate cloud of smoke at wot. Does it pay to add a little more pulse width or would that just create more heat? I am just looking for a little more power.

 

[dmaxvaz]

Take some pulsewidth out and increase rail psi, you shouldnt need that much pulsewidth, with the 40% overs

 

[mudygmc]

How high can the rail pressure go? When I log the tune the rail psi shoots up to 26107 and never goes higher. The smoke isn't bad like I'm over fueling. I ran a 2600pw tune and the rail pressure was the same. Wouldn't pulling pulse width out of the tune lower power?

 

[dmaxvaz]

it shoots up there, but does it hold the rp at 26,xxx? i've removed 650 pw from my tune with very little to no loss in power.

 

[mudygmc]

It shoots up and stays at 26107psi. It will hold there and drop to 25750psi on my 3-4 shift then be right back at 26107. I have never seen it go any higher. I can bury the speedo and it stays at 26107. That is why I think something is limiting it there.

 

[DuramaxPowered]

the sensor scaling stops 26107....

 

[TrentNell]

Be careful with that high of pulse width , if it happend to actually hold rail pressure you motor is going to pop in a big hurry , it might take a bit to catch up to you but something will break . I would start around 21-2200 maybe go higher if needed .


Make sure your logging actual rail and not cammanded also . all we care about is actual rail pressure

 

[DuramaxPowered]

look at {B0203} in your tune. See how at 4.53 volts and above the value is 180MPA, change it to read out linear and you'll be able to read the pressure higher.

 

[DuramaxPowered]

look at this, and make yours the same http://www.duramaxdiesels.com/forum/showpost.php?p=118402&postcount=133

 

[mudygmc]

So the table would look like this.
4.53 181
4.69 188
4.84 195
5.00 202
The numbers rounded themselves up when I entered them. This will give me actual rail pressure beyond 26107psi?
I log both desired and actual rail pressure. Desired was 271xx and actual showed the 26107. How high could the pressure actually go? If my smoke cloud is cleaning up( it's still there but not as black as say stock turbo, injectors and a PPE hot +2 on level 10) I am not over fueling it really. What would be the reason for pulling out so much puslewidth?

 

[sweetdiesel]

look at {B0203} in your tune. See how at 4.53 volts and above the value is 180MPA, change it to read out linear and you'll be able to read the pressure higher.

cool

 

[TrentNell]

So the table would look like this.
4.53 181
4.69 188
4.84 195
5.00 202
The numbers rounded themselves up when I entered them. This will give me actual rail pressure beyond 26107psi?
I log both desired and actual rail pressure. Desired was 271xx and actual showed the 26107. How high could the pressure actually go? If my smoke cloud is cleaning up( it's still there but not as black as say stock turbo, injectors and a PPE hot +2 on level 10) I am not over fueling it really. What would be the reason for pulling out so much puslewidth?

That was based purly off what i have seen on my 45% overs along with 2 other trucks that run 45% overs as well, built motor guys with dual cp3's that run low elevens are only running 2750-2800 . my big worry would be your rods bending , unless your motors built and not in your sig, or you got one planned for if it was too pop , my dyno run was a 2750 tune with dual fuelers and big twins and i asked if i cleaned up all the fuel and was told no that it still smoked your truck /injectors could be very different than mine .

 

[mudygmc]

I run 40-42psi boost. It still smokes but not that bad. I don't want to blow it up as the funds for a build aren't there yet. I am just trying to get some good power out of my setup for pulling. I am not making headway on the dodges this year. Any rough estimate on my hp #'s? I haven't had time to dyno at all.

 

[othrgrl]

If you are holding that kind of pressure you should be able to get 600hp out of it with that turbo. As trent said you shouldn't need that high of PW if you have true 45% over injectors and that much pressure - that would be ALOT of fuel. A drive pressure gauge is the best way to get a Cheetah dialed in.

 

[mudygmc]

What is the easiest way to put in a drive pressure guage? I obviously want the truck as efficient as possible. It will be a while before the funds are there to build the motor.

 

[RodZZilla]

You could tap the pass side manifold to run a guage from there. Some people have also tapped their up pipes.

 

[mudygmc]

So I am just putting another boost guage in the exhaust side. I have a bd manifold with a blocked off port. I assume you use copper line? Or what do you use for the heat?

 

[RodZZilla]

Coiled copper will help w/the heat. I have heard some people use a inline filter to help w/the soot buildup. If you are not using the port on the BD, that would be the easiest place to start.

 

[RodZZilla]

I think Larry Jewel has a post on how he did his.

Found it

http://208.109.104.11/forum/showthread.php?t=2613&highlight=drive+pressure+gauge

 

[mudygmc]

So could somebody kind of help me with a shopping list. I would like to do this on a reasonable budget, but want parts that are accurate and that will last. Is an electronic guage the best option? Do you run like a -3 an braided hose to the sensor say 3ft away to keep the sensor cool and clean? I just want to do it right the first time. I appreciate all the info.