My drive pressure numbers

trik396

trik396

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Joined
Feb 13, 2007
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150
Just wondering what you guys think about these numbers.

20psi boost, drive pressure (tip) 10psi
40psi boost,........................... 35psi
45psi............................tick over 40psi
50psi........................... keeps climbing past 60psi somewhere

had to get outta it due to traffic.

Can anyone tell me what the heck all this means? :ft:
 
It came from II wastegated at 45psi and that's what I saw as a max boost number until I added more fuel... alot more than what I had. Now I get past 50 to around 52-53lbs. Guess I have to "screw" around with it some...:hehe:
 
II told me my 62/12 was good to 60psi. My drive pressures at 48psi were well north of 60psi. So I backed it down to 38psi and they are now a tick under 40psi.
 
put your wastgate adjustment at about 46-47lbs boost, that will be right at 1:1, but if you add more fuel/nitrous it may get higher and you will need to compensate for this, by lowering again, higher boost does not mean higher hp, anything above 1:1 is not going to help. hope this helps.
 
DIESEL POWER said:
put your wastgate adjustment at about 46-47lbs boost, that will be right at 1:1, but if you add more fuel/nitrous it may get higher and you will need to compensate for this, by lowering again, higher boost does not mean higher hp, anything above 1:1 is not going to help. hope this helps.
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:umno:

Tell that to Getblown5.9- he brought down egts by boosting over 45 lbs with a Silverbullet. There can be some benefit to more boost if the turbo's not off its map, but its a diminishing return. The important thing is to keep both drive and boost to a level where your head gasket can survive.

Trike- on the Silverbullet can't you just extend the actuator a little to help bring boost back down? Or tighten the thing on the elbow?
 
My Bullet runs 1 to 1 at 47 psi, add two stages of N2O and it goes to 52.....seems to control it fine! Now we'll have to see what happens when you add a real set of injectors.

Jim
 
Jim Fulmer said:
My Bullet runs 1 to 1 at 47 psi, add two stages of N2O and it goes to 52.....seems to control it fine! Now we'll have to see what happens when you add a real set of injectors.

Jim
Click to expand...

Is it the 12v head causing that? My bullet is running 1 to 1 at 58 to 62 psi? CR on fuel only. Yes, I do have a real set of BIG sticks. I had to adj to this because it would go over 70psi before.
 
Ph4tty said:
:umno:

Tell that to Getblown5.9- he brought down egts by boosting over 45 lbs with a Silverbullet. There can be some benefit to more boost if the turbo's not off its map, but its a diminishing return. The important thing is to keep both drive and boost to a level where your head gasket can survive.

Trike- on the Silverbullet can't you just extend the actuator a little to help bring boost back down? Or tighten the thing on the elbow?
Click to expand...

ok cause i did my research and you didnt, i wont hold it against you.

the siver 64 is whats the main subject in this thread, getblown5.9's is a 66 silver----big difference between the two on drive psi and boost at 1:1, believe me i know.
 
For those of us who haven't done their research, why is there a big difference between a silver 64 and a silver 66 when it comes to drive pressure?
 
BgBlDodge said:
For those of us who haven't done their research, why is there a big difference between a silver 64 and a silver 66 when it comes to drive pressure?
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normally when you go bigger on the compressor side it will take more drive psi to make more boost psi.

a 64 may be 1:1 at 46 lbs

a 66 may be 1:1 at 49-52 lbs or even higher. so one # is not valid for all turbo's, each has it's own correct 1:1. manily cause theres more mass to move!
 
Since you say "may," does that mean it's a fact, or an inference you are making because II told you??

Why don't you show us a map of each compressor, and point us to the differences in them, and explain how that would affect drive pressure vs. boost, and efficiency?

Chris
 
II told me my 62 was good up to 60psi. Looking at drive pressures at 48psi I can promise you that ain't a fact. It was well over 60psi of TIP at 48psi of boost. At 40psi it was 1:1.
 
BgBlDodge said:
II told me my 62 was good up to 60psi. Looking at drive pressures at 48psi I can promise you that ain't a fact. It was well over 60psi of TIP at 48psi of boost. At 40psi it was 1:1.
Click to expand...

This might have contributed to the condition of your motor right now.$.02
 
BgBlDodge said:
II told me my 62 was good up to 60psi. Looking at drive pressures at 48psi I can promise you that ain't a fact. It was well over 60psi of TIP at 48psi of boost. At 40psi it was 1:1.
Click to expand...
I think what II said would be that the shaft & internals could handle 60psi, not that the drive pressure would be ok at 60psi. The reason I say this is because when I bought the HTT PS66, they said 70psi wouldn't kill it but 45psi would be optimal in my setup since that's where the compressor goes out of the map.
 
sootman said:
This might have contributed to the condition of your motor right now.$.02
Click to expand...

This thought has crossed my mind and is why I'm kinda leaning towards a headgasket after talking to hellmann. That along with the meth might have popped it.
 
joefarmer said:
I think what II said would be that the shaft & internals could handle 60psi, not that the drive pressure would be ok at 60psi. The reason I say this is because when I bought the HTT PS66, they said 70psi wouldn't kill it but 45psi would be optimal in my setup since that's where the compressor goes out of the map.
Click to expand...

I distinctly asked if drive pressures would be ok at 60psi and he said they would be on the ragged edge but would be fine.
 
BgBlDodge said:
This thought has crossed my mind and is why I'm kinda leaning towards a headgasket after talking to hellmann. That along with the meth might have popped it.
Click to expand...
Water is OK. Meth is never going into my cylinder's. $.02
 
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