The newest 100% bolt on Greddy Hybrid turbocharger!
05-27-2010, 06:02 PM
#776
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iirc correctly brettus, yes. at a given compressor rpm it will flow the same with 1" pipe or 3" pipe. it will just be at wildy different pressures and temps
Last edited by paulmasoner; 05-27-2010 at 06:06 PM.
05-27-2010, 06:14 PM
#777
BUT not at the same wastegate setting . You need to block off the wastegate a lot more and have the compressor spinning a lot faster makeing hotter air at a higher pressure to get the same flow .
Exactly the problem these guys are having - they can't contol the wastegate because (apart from the weak *** greddy actuator) there is so much restriction downstream of the turbo that it just blows open when they try and up the boost .
Also explains why the only guys that actually have made good power on any Greddy upgrade have jammed the WG closed like I do .....
Last edited by Brettus; 05-27-2010 at 06:35 PM.
05-27-2010, 07:47 PM
#778
This is hopeless and I don't have any more time to dedicate to turbo basics.
Grab Hartman's book or Bell's book.
Understand how the discharge volute and compressor A/R work to convert velocity into pressure.
Then, come back and post what you find.
BTW - a straw would be a restriction, but the effect wouldn't be what you think in this location.
Grab Hartman's book or Bell's book.
Understand how the discharge volute and compressor A/R work to convert velocity into pressure.
Then, come back and post what you find.
BTW - a straw would be a restriction, but the effect wouldn't be what you think in this location.
05-27-2010, 08:13 PM
#779
This is hopeless and I don't have any more time to dedicate to turbo basics.
Grab Hartman's book or Bell's book.
Understand how the discharge volute and compressor A/R work to convert velocity into pressure.
Then, come back and post what you find.
BTW - a straw would be a restriction, but the effect wouldn't be what you think in this location.
Grab Hartman's book or Bell's book.
Understand how the discharge volute and compressor A/R work to convert velocity into pressure.
Then, come back and post what you find.
BTW - a straw would be a restriction, but the effect wouldn't be what you think in this location.
There were good reasons Greddy designed that piece the way they did
1/there was no room to do anything different with the turbo they had for the job
2/It really didn't matter at the flow a stock Greddy turbo produces .
If you were designing a 400whp turbo setup there is no way in the world you would use a restrictive bend like that Greddy one .
Found this on the Garrett site :
Last edited by Brettus; 05-27-2010 at 11:01 PM.
05-28-2010, 09:41 AM
#780
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The worst restriction to flow on the Greddy kit is the bend on top of the turbo . I believe this a big part of the problem guys are having extracting decent power from these upgrades.
Suggestion :
Bryan , when you do these turbo upgrades offer (as an extra charge) to machine off the flange at the outlet such that it is suitable to fit a 2" 90degree silicone coupler .
Then all we need is a short 2" extension pipe to fit to the existing tube .
The improvement from that alone will be huge .
I plan to do this when my turbo needs rebuilding but that might not be for a while .
Suggestion :
Bryan , when you do these turbo upgrades offer (as an extra charge) to machine off the flange at the outlet such that it is suitable to fit a 2" 90degree silicone coupler .
Then all we need is a short 2" extension pipe to fit to the existing tube .
The improvement from that alone will be huge .
I plan to do this when my turbo needs rebuilding but that might not be for a while .
What makes you think a 90° silicone coupler is less of a restriction?
You still aren't getting how the diffuser in a turbo works.
I use a 135°, 2" bend at the outlet of my turbo. It is absolutely no restriction (as the pre-bend pressure is exactly the same as the pre-intercooler pressure).
You still aren't getting how the diffuser in a turbo works.
I use a 135°, 2" bend at the outlet of my turbo. It is absolutely no restriction (as the pre-bend pressure is exactly the same as the pre-intercooler pressure).
05-28-2010, 10:34 AM
#781
Turbocharger Guru
Thread Starter
There is pressure and volume drop with pipes and bends (might be a fraction of a PSI but its there). Depends on the radius and the size/length of the tube and volume that you are flowing through the tube.
I have seen some rigged pipes that were crush bent, small diameter pipes, and slash cut strait pipe, and PVC as intercooler pipes. Also there are pipes that were too big for the turbocharger. All of which works beleive it or not lol.
Mandrel bent pipes work best for flow. There is a science to intercooler piping sizes. There is absolutely no point to make the upper intercooler pipes bigger than the inducer of the compressor wheel (unless you have an absurd amount of bends or length). The lower intercooler pipe doesn't have to be as big as the upper IC pipe. You want to keep air speed up as high as possible without restriction. It will improve response and the system will be properly set up of for the turbocharger.
I have seen some rigged pipes that were crush bent, small diameter pipes, and slash cut strait pipe, and PVC as intercooler pipes. Also there are pipes that were too big for the turbocharger. All of which works beleive it or not lol.
Mandrel bent pipes work best for flow. There is a science to intercooler piping sizes. There is absolutely no point to make the upper intercooler pipes bigger than the inducer of the compressor wheel (unless you have an absurd amount of bends or length). The lower intercooler pipe doesn't have to be as big as the upper IC pipe. You want to keep air speed up as high as possible without restriction. It will improve response and the system will be properly set up of for the turbocharger.
05-28-2010, 03:54 PM
#785
From what I understand MM is trying to say that a Flow Restriction and a Pressure Drop are not the same things. That 90deg bend may restrict flow but it will not cause a pressure drop in the system... hence turbo outlet pressure = IC inlet pressure. I think you may be trying to relate flow and pressure to closely.
The compressor on a centrifugal doesn't actually make pressure. It increases velocity.
Pressure is created in the volute of the compressor housing. The"bend" in question - because of its shape and change in diameter - is actually part of the volute of the compressor housing.
Look at how right-angle discharge outlets work on high-end TCs. It is the same.
You have to understand how the A/R of the compressor housing is setup and how the velocity/pressure relationship works.
05-29-2010, 12:39 AM
#786
Look at the whole thing in place on the car - it is obvious it was designed that way for clearance reasons .
Some pics of these "high end" turbos would help .
Last edited by Brettus; 05-29-2010 at 12:52 AM.
05-29-2010, 12:55 AM
#787
For Christ's sake, would you just read the things that I recommended? This is NOT advanced stuff.
Do they not have Google down there?
Last edited by MazdaManiac; 05-29-2010 at 12:59 AM.
05-29-2010, 01:59 AM
#791
/\ if only the Greddy were designed like that ..... (or the one MM posted )
here is the greddy part again for comparison with the above .
couple of things about it :
The bend radius is very small - perhaps 23mm or 0.5X tube inside diameter vs at least 1x diameter for the one MM posted .
The actual hole size is a lot smaller than the inlet dia. of the turbo (approx. 46mm ).
Which would be OK for the turbo it was originally fitted to ,the stock Greddy with a 50mm inlet, but not the BNR with a 60mm inlet.
Both NGOs and the one MM posted are a similar dia. to the turbo inlet .
here is the greddy part again for comparison with the above .
couple of things about it :
The bend radius is very small - perhaps 23mm or 0.5X tube inside diameter vs at least 1x diameter for the one MM posted .
The actual hole size is a lot smaller than the inlet dia. of the turbo (approx. 46mm ).
Which would be OK for the turbo it was originally fitted to ,the stock Greddy with a 50mm inlet, but not the BNR with a 60mm inlet.
Both NGOs and the one MM posted are a similar dia. to the turbo inlet .
Last edited by Brettus; 05-29-2010 at 08:31 PM.
05-29-2010, 06:36 PM
#793
05-29-2010, 09:34 PM
#794
Turbocharger Guru
Thread Starter
You guys are looking at the wrong place for restriction in the turbocharger. That dinky little pipe will flow more than what you think! You will max out the turbine housing well before you max out that compressor housing. 10 cm2 is very small (.72 a/r give or take). That housing will only make around 350-360 RWHP max. Doesn't matter what compressor you put in that turbo, it is game over for the turbine housing...
05-29-2010, 09:47 PM
#795
Well - can't argue with that . If that is the case then my suggestion from 6 pages ago is a good one - IE don't offer the 58lb 60-1 compressor . Just the 48lb one .........
https://www.rx8club.com/showpost.php...&postcount=636
https://www.rx8club.com/showpost.php...&postcount=636
05-29-2010, 10:01 PM
#796
Turbocharger Guru
Thread Starter
05-29-2010, 10:13 PM
#797
Turbocharger Guru
Thread Starter
Well - can't argue with that . If that is the case then my suggestion from 6 pages ago is a good one - IE don't offer the 58lb 60-1 compressor . Just the 48lb one .........
https://www.rx8club.com/showpost.php...&postcount=636
https://www.rx8club.com/showpost.php...&postcount=636
I have never seen a rotary make 360 RWHP on a 50 trim. Math says yes, but I have never laid my eyes on a dyno sheet laying 360 RWHP down with a 50 trim compressor wheel. The reasoning behind the comrpessor of choice is b/c is has been proven over an over. Once this bottleneck of the intercooler is taken care of, numbers will come!
I use the 60-1 for 350-360 RWHP applications all the time. My T2 Stage 3 is a stock turbine wheel clipped with the 60-1. Guys trap 118 MPH at the track with it. Can the stage 3 be improved? yes. Stage 4 has an upgraded turbine wheel and is benificial for 3 more psi of boost on the stock T2 turbine housing machined for the P trim turbine upgrade.
Last edited by Bryan@BNR; 05-29-2010 at 10:27 PM.
05-29-2010, 10:32 PM
#798
So you agree there IS a bottleneck the question is ----- where ?
Here are the likely possibilities :
1/The whole wastegate actuator issue
2/The turbo exit 90deg
3/The 50mm 90 deg. into the IC
4/The IC itself (I know from my own trials that the stock Greddy IC is only responsible for a fraction of the overall pressure drop)
What other possibilities do you see ?
05-29-2010, 10:48 PM
#799
Turbocharger Guru
Thread Starter
OK - but we have not seen 300 with the 60-1 yet - let alone 350 .
So you agree there IS a bottleneck the question is ----- where ?
Here are the likely possibilities :
1/The whole wastegate actuator issue
2/The turbo exit 90deg
3/The 50mm 90 deg. into the IC
4/The IC itself (I know from my own trials that the stock Greddy IC is only responsible for a fraction of the overall pressure drop)
What other possibilities do you see ?
So you agree there IS a bottleneck the question is ----- where ?
Here are the likely possibilities :
1/The whole wastegate actuator issue
2/The turbo exit 90deg
3/The 50mm 90 deg. into the IC
4/The IC itself (I know from my own trials that the stock Greddy IC is only responsible for a fraction of the overall pressure drop)
What other possibilities do you see ?
I have made 400 RWHP on a 60-1 in my own dated turbo 2, BDC even made 438(1 and 7/8" upper intercooler pipe). Not to mention about 100 other customers I have. How can you make over 300 RWHP when only 6 psi is getting through the intercooler?
If you made 333 RWHP on a Greddy intercooler, I would have to see a trap speed at the track to believe that dyno sheet. We all know dyno sheets can be "corrected" lol. My wifes FD dynoed 329 RWHP and trapped 114 MPH on regular radial tires. I would say the extra weight of the RX8, you should be atleast at 110-111 mph if you make 333. Go take it to the track and see what speed you get.
Bryan@BNR
Last edited by Bryan@BNR; 05-29-2010 at 11:43 PM.
05-30-2010, 02:02 AM
#800
Bottleneck is the intercooler. After the hard 90 coming out of the turbo, there is 16 psi constant coming out of the turbocharger. Boost gauge on the engine side is fluctuating between 6 and 8 psi. That right there tells you there is a restriction in the intercooler. If it were to be the wastegate, the boost would fall off up in the top RPM, but the boost was a consistant 16 psi on the turbo side.
I have made 400 RWHP on a 60-1 in my own dated turbo 2, BDC even made 438(1 and 7/8" upper intercooler pipe). Not to mention about 100 other customers I have. How can you make over 300 RWHP when only 6 psi is getting through the intercooler?
If you made 333 RWHP on a Greddy intercooler, I would have to see a trap speed at the track to believe that dyno sheet. We all know dyno sheets can be "corrected" lol. My wifes FD dynoed 329 RWHP and trapped 114 MPH on regular radial tires. I would say the extra weight of the RX8, you should be atleast at 110-111 mph if you make 333. Go take it to the track and see what speed you get.
Bryan@BNR
I have made 400 RWHP on a 60-1 in my own dated turbo 2, BDC even made 438(1 and 7/8" upper intercooler pipe). Not to mention about 100 other customers I have. How can you make over 300 RWHP when only 6 psi is getting through the intercooler?
If you made 333 RWHP on a Greddy intercooler, I would have to see a trap speed at the track to believe that dyno sheet. We all know dyno sheets can be "corrected" lol. My wifes FD dynoed 329 RWHP and trapped 114 MPH on regular radial tires. I would say the extra weight of the RX8, you should be atleast at 110-111 mph if you make 333. Go take it to the track and see what speed you get.
Bryan@BNR
Also videoed a run with a very soft takeoff and reached 110mph(176km/hr) in approx. 13.3s . See utube clip below .
http://www.youtube.com/watch?v=K7NMIKfdBaw
A bigger intercooler (12x3) improved the overall pressure drop for my setup by less than 1psi .
Last edited by Brettus; 05-30-2010 at 02:11 AM.