Boost/Drive Pressure numbers with 74+mm turbo's

Marty · May 29, 2011

Just trying to see what other people are running.

I am measuring boost from the intake y mechanically, and I am measuring drive pressure from the EBPS location mechanically as well.

At a steady 40 psi of boost, I am seeing 47 psi drive. This is with a S475/83 1.0 T4.

It's pretty drivable with 400/600's, but I know I need more turbo for this setup as 40 psi of boost is about 1/4 throttle. Believe me, I'm already thinking 100+mm in the passenger fender well but for now I'll settle with this turbo. Either way, it's just a turbo to drive the truck around on...

powerstrokenstang · May 30, 2011

i dont have any hard numbers of my own but james barder ran the same turbo i got and i believe he said 1:1 till 35psi and at 50 psi drive was like 55. thats s475 96/88 exhaust wheel 1.10 t-6. it does a real good job w/ the 350-370cc i inject goin down the track. i get about 60psi on a good track. drives seem good there, it doesnt try to snuff or anything.

Marty · May 30, 2011

Yeah, drive will be less with the larger turbine wheel and housing. I used to have the 475/88 1.15 t4i... it definitely was not as drivable as this turbo though.

I hit 50 psi in the lowest setting last night, but I didn't get any drive pressure readings because I guess my line clogged up or something. I will check it out today and go try it again. With S475/88 1.15 T4i that setting never hit more then 40 or so psi.

TARM · May 30, 2011

Mary,

I am getting ready to install a drive gauge so i did some reading on it by some guys that have been runing them on what works best:

To try to prevent any clogging with the drive psi gauge make sure there are no leaks at all. Even the smallest ones in the tube will alLow soot up the tube. Using the smallest inside diameter hose possible is suppose to be helpful as well. What you are trying to do is not have any air exchange with what's in the line. Sort of like a brake line. It will only pressurize the air already in the tube. If there is a leak you get air flow up the tube and soot build up cuasing a clog.

V-Ref · May 30, 2011

Marty said:
Just trying to see what other people are running.

I am measuring boost from the intake y mechanically, and I am measuring drive pressure from the EBPS location mechanically as well.

At a steady 40 psi of boost, I am seeing 47 psi drive. This is with a S475/83 1.0 T4.

It's pretty drivable with 400/600's, but I know I need more turbo for this setup as 40 psi of boost is about 1/4 throttle. Believe me, I'm already thinking 100+mm in the passenger fender well but for now I'll settle with this turbo. Either way, it's just a turbo to drive the truck around on...

Marty

I was about to start a thread asking the same thing. Looking forward to the data posted here.

Can you post a vid of your boost/egt guage during a full power run...like to see how responsive that turbo is.

Just have a couple logs so far for drive pressure/boost. I'm learning AE, and have a slow laptop...and not sure the factory BP sensor can read over 48 psi? AE is only grabbing like 2 or 3 data points during a full power run when I'm somewhere between 20 psi and 55 psi. Example...AE captures peak boost of 27 psi, even though I observe 50+ psi.

To be clear...what are folks calling "data logging"? To me "data logging" represents two points of data at a specific point in time time...eyeballing a boost and dp guage during a full power run would seem to be full of room of error for interpretation

The peak recall function of the ISSPRO EV2 would seem to be a good snap shot of peak boost vs drive pressure...or a video that capture a boost guage and drive pressure guage...then go back and "log" the screen shots....

Maybe I'm overthinking this......

The reason I ask...is what "system" folks are using to derive this data?

Thanks!

V-Ref · May 30, 2011

To your original post though...at 24 psi of what AE calls "Manifold Guage Pressure", AE data logs 38 psi of "Exhaust Back Pressure". I'll see if I can't post some better data logs later today.

PTE 76mm billet inducer (not sure on exducer), Dual ceramic BB air cooled center section, 75/83 compressor wheel, .81 undivided T4 compressor housing. 200% nozzles. Turbo needs 800 deg, 2100+ rpm, and then it "lights". Hard to see/log anything in the 20-40 psi boost range....kind of on/off situation.

V-Ref · May 30, 2011

trying...

Marty..not sure my data is going to be of much use. I can't make sense of what AE is logging, and don't want to sidetrack your thread. This run saw 53 psi before blowing a boot.

Time Injector Control Pressure (PSI) Manifold Gauge Pressure (PSI) Engine RPM (RPM) Exhaust Back Pressure (PSI)-14.7 Exhaust Back Pressure (PSI) Vehicle Speed (MPH)

2:40:07.427 825.28 0.72 1611.2 2.12 16.82 21
2:40:08.316 866.01 0.80 1643.7 2.3 17.00 21
2:40:09.205 881.84 0.94 1668.7 2.3 17.00 21
2:40:10.094 908.43 0.91 1696.7 2.37 17.07 22
2:40:10.984 923.14 0.91 1685.9 2.45 17.15 22
2:40:11.873 946.33 0.98 1714.4 2.45 17.15 22
2:40:12.762 1031.17 1.05 1760.4 2.81 17.51 23
2:40:13.651 1192.38 1.27 1813.2 3.28 17.98 23
2:40:14.556 1390.93 1.38 1897.4 3.86 18.56 25
2:40:15.445 1633.59 1.70 2001.9 4.22 18.92 26
2:40:16.334 1791.97 4.64 2081.9 7.99 22.69 44
2:40:26.038 2542.02 5.47 2186.4 8.75 23.45 45
2:40:26.927 2556.16 6.09 2250.7 9.77 24.47 47
2:40:27.816 2616.12 6.85 2349.4 10.57 25.27 48
2:40:28.705 2664.76 7.94 2415.9 12.41 27.11 50
2:40:29.594 2808.44 9.21 2476.6 14.3 29.00 51
2:40:30.484 2750.18 10.69 2543.9 14.73 29.43 52
2:40:31.373 2664.76 10.66 2591.1 14.92 29.62 53
2:40:32.262 2684.00 11.09 2638.6 16.11 30.81 54
2:40:37.550 3011.50 8.26 2131.7 13.43 28.13 57
2:40:38.533 2689.09 10.48 2186.4 15.5 30.20 60
2:40:39.422 2910.25 14.10 2272.4 18.65 33.35 62
2:40:40.312 2919.87 16.93 2370.1 23.07 37.77 64
2:40:41.201 2907.99 21.68 2494.6 30.87 45.57 68
2:40:42.090 2823.71 -0.14 628.2 0.16 14.86 47

TARM · May 30, 2011

V-ref,

You likely. Already know this but just to correct it when comparing to gauge boost numbers, the bp sensor readings are absolute psi.

powerstrokenstang · May 30, 2011

I am wonderin if the 88 wheel is the only way to keep them in check. Kinda like when i had a 71 mm ex wheel on my old h2e. Went from a 19 to a 22 housing and it never changed drives, the wheel was just to small. I wonder if you can get a housong smaller than a 1.15 made for the 88 mm wheel to keep it really drivable. Heck my 1.10 t6 doesnt lite till 25-2600 lol.

Marty · May 30, 2011

Tarm

My line blew off. Time for a clamp on the barbed adapter.

V-Ref said:
Marty

I was about to start a thread asking the same thing. Looking forward to the data posted here.

Can you post a vid of your boost/egt guage during a full power run...like to see how responsive that turbo is.

Just have a couple logs so far for drive pressure/boost. I'm learning AE, and have a slow laptop...and not sure the factory BP sensor can read over 48 psi? AE is only grabbing like 2 or 3 data points during a full power run when I'm somewhere between 20 psi and 55 psi. Example...AE captures peak boost of 27 psi, even though I observe 50+ psi.

To be clear...what are folks calling "data logging"? To me "data logging" represents two points of data at a specific point in time time...eyeballing a boost and dp guage during a full power run would seem to be full of room of error for interpretation

The peak recall function of the ISSPRO EV2 would seem to be a good snap shot of peak boost vs drive pressure...or a video that capture a boost guage and drive pressure guage...then go back and "log" the screen shots....

Maybe I'm overthinking this......

The reason I ask...is what "system" folks are using to derive this data?

Thanks!

Subtract 15 from whatever your AE displays and also I don't use AE. I use a max recall on the BP with a BD X monitor and I get the boost to a specific pressure and hold it there.

I can't even run a full power run. My lowest tune hits 50 psi.

powerstrokenstang said:
I am wonderin if the 88 wheel is the only way to keep them in check. Kinda like when i had a 71 mm ex wheel on my old h2e. Went from a 19 to a 22 housing and it never changed drives, the wheel was just to small. I wonder if you can get a housong smaller than a 1.15 made for the 88 mm wheel to keep it really drivable. Heck my 1.10 t6 doesnt lite till 25-2600 lol.

I agree.

Short Bus · May 30, 2011

damn marty your small tune must have a chit ton of fuel!

Marty · May 31, 2011

Yeah I guess so. It used to only make 35 to 40 at most if i recall correctly.

It doesn't smoke that bad, about like a 140 tune on a stock truck. I have one other tune that is just for cruise control that doesn't smoke at all. Doesn't accelerate through the gears very well.

These are also 2 year old tunes for 300/400s and I'm running 400/600s....

a_moore · May 31, 2011

Sounds like you are ready for a GT45/GT55 compound setup to me. One big gate on each head to keep the 45 out of low earth orbit.

Or in Borg terms, an S480 and S500 compound setup gated as above. The brand difference is good to save you a few thousand...

Sounds mean Marty. Good to see it running again.

Suns_PSD · May 31, 2011

Well what you have a very good balance between response and top-end hp.

You know you might hit 40psi at 1/4 throttle but only 45 psi at 1/2 throttle. For a single I think you are going to find that to be about as large as you can go and still be drivable.

Also, I have very similiar boost/ BP #'s w/ my large single and it's enough for my 200% nozzles. I pretty much run out of usable pw exactly as my turbo is reaching the end of it's compressor map and BP is just beganning to really climb. I have livable response down low, insane mid-top hp, and very livable smoke levels at all times in my one and only program that is no slouch.

Dieselfever · May 31, 2011

When I run the true S475 compressor housing on my pulling truck it is ~50 psi of boost to ~60 psi of drive. That is with the 88mm turbine wheel and 1.15 turbine housing. When I put the 2.6 clipped wheel compressor housing on it knocks the boost down to 40-42 psi

-Michael

Hotrodtractor · May 31, 2011

Dieselfever said:
When I run the true S475 compressor housing on my pulling truck it is ~50 psi of boost to ~60 psi of drive. That is with the 88mm turbine wheel and 1.15 turbine housing. When I put the 2.6 clipped wheel compressor housing on it knocks the boost down to 40-42 psi

-Michael

I haven't taken any measurements on the truck I just set up yet - but did you notice a drop in your drive pressures as well when the boost dropped down into the 40-42 psi range? I know there is a lot more to be had out of the turbo setup that I installed with some simple housing tweaks that would also allow it to stay within the rules.

Dieselfever · May 31, 2011

Drive pressure was still in the higher 50's-low 60's

Marty · Jun 1, 2011

a_moore said:
Sounds like you are ready for a GT45/GT55 compound setup to me. One big gate on each head to keep the 45 out of low earth orbit.

Or in Borg terms, an S480 and S500 compound setup gated as above. The brand difference is good to save you a few thousand...

Sounds mean Marty. Good to see it running again.

I was actually thinking dropping to 471/83 with smaller turbine housing with something like a s5 or gt55 would be better. Gate from collector to intermediate, gate from intermediate to downpipe.

That's if I did compounds, my original intention was a billet s480/92 1.15 from forced inductions but idk....

a_moore · Jun 1, 2011

Marty said:
I was actually thinking dropping to 471/83 with smaller turbine housing with something like a s5 or gt55 would be better. Gate from collector to intermediate, gate from intermediate to downpipe.

That's if I did compounds, my original intention was a billet s480/92 1.15 from forced inductions but idk....

I am just guessing that the fuel and nozzle you are running might need 75-80 psi to make power to its potential. A single will not fill a 60+ psi order for very long, nos will, but then you run into it overspinning again.

That sinlge should work fine, but you will need to spray and gate it to get all the fuel to use IMO.