Brettus turbo 111 (the ultimate Renesis turbo ?)
06-14-2015, 06:37 PM
#52
Or
*the gas is more turbulent in on than the other.
Yeah I think having only half the time directly exposed to flowing hot exhaust gasses will make a big difference. 6ms may not seem like a lot of time, but remember the exhaust pulses are short too. It's not just the temperature it's the flow too, you can put your hand in a 500deg oven for a while and not get burned, but if you have a heat gun blowing 500deg air at your hand it will burn quick.
*the gas is more turbulent in on than the other.
Yeah I think having only half the time directly exposed to flowing hot exhaust gasses will make a big difference. 6ms may not seem like a lot of time, but remember the exhaust pulses are short too. It's not just the temperature it's the flow too, you can put your hand in a 500deg oven for a while and not get burned, but if you have a heat gun blowing 500deg air at your hand it will burn quick.
06-14-2015, 06:54 PM
#53
Or
*the gas is more turbulent in on than the other.
Yeah I think having only half the time directly exposed to flowing hot exhaust gasses will make a big difference. 6ms may not seem like a lot of time, but remember the exhaust pulses are short too. It's not just the temperature it's the flow too, you can put your hand in a 500deg oven for a while and not get burned, but if you have a heat gun blowing 500deg air at your hand it will burn quick.
*the gas is more turbulent in on than the other.
Yeah I think having only half the time directly exposed to flowing hot exhaust gasses will make a big difference. 6ms may not seem like a lot of time, but remember the exhaust pulses are short too. It's not just the temperature it's the flow too, you can put your hand in a 500deg oven for a while and not get burned, but if you have a heat gun blowing 500deg air at your hand it will burn quick.
Do you really think there can possibly be LESS energy in the tube glowing red than the one that isn't ?
Last edited by Brettus; 06-14-2015 at 07:28 PM.
06-14-2015, 08:05 PM
#55
I think it has more to do with contact time. A cooler sustained torch flame for example will heat metal much faster than a hotter flame which is only on the metal half the time. Even at higher flow rates the exhaust temperature isn't any hotter, it just has a bit more turbulence from the higher flow. 6ms doesn't seem like a lot of time, but that's per revolution, if you think about it like a percentage it makes a lot more sense.
06-14-2015, 08:41 PM
#56
It could be for several reasons. The center port could have more flow in total, or it could just be more turbulent flow, or it could have more total contact time.
I think it has more to do with contact time. A cooler sustained torch flame for example will heat metal much faster than a hotter flame which is only on the metal half the time. Even at higher flow rates the exhaust temperature isn't any hotter, it just has a bit more turbulence from the higher flow. 6ms doesn't seem like a lot of time, but that's per revolution, if you think about it like a percentage it makes a lot more sense.
I think it has more to do with contact time. A cooler sustained torch flame for example will heat metal much faster than a hotter flame which is only on the metal half the time. Even at higher flow rates the exhaust temperature isn't any hotter, it just has a bit more turbulence from the higher flow. 6ms doesn't seem like a lot of time, but that's per revolution, if you think about it like a percentage it makes a lot more sense.
Anyway .... suffice it to say that the center tube already flows a good % of the total flow in an NA engine.... I hope it's enough for what I'm trying to do!
It will be interesting to see if I manage to take this to the point where the siamese creates too much backpressure and causes boost creep as that would give us some good info on what is possible.
The ability to fully open the WG via that plumbing/light spring as you suggested will be a major help to that end i'm sure .
Last edited by Brettus; 06-14-2015 at 11:49 PM.
06-14-2015, 11:46 PM
#57
I'll be surprised if it has full boost by 3500 rpm. Partially because of the AR even if divided, but partially because of why the center port exists; it won't be clearing out gasses on the center iron side during spool-up because the wastegate will be closed and not allowing any center port flow. There will be an efficiency issue with the center port closed off. The magnitude is difficult to assess though.
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I'm skeptical that the center port has enough flow potential to effectively control boost on it's own. As a restictive port it will potentially be self defeating for wastegate control. More backpressure can force more flow through it, but that same backpressure is also spooling the compressor wheel to pump out more boost. To be effective it must offer the path of least resistance *for both rotors*, which IMO is questionable. So potentially you are in an escalating loop that may prove difficult to control.
06-15-2015, 04:49 PM
#59
I was going to wait till it was done but thought it might be worthwhile discussing first ... in case there was something I had missed that meant it was a waste of time and money. Thanks for the input .
Last edited by Brettus; 06-15-2015 at 05:02 PM.
06-15-2015, 07:14 PM
#60
Hybrid Greddy Boosted
Awesome project, good luck with it. ETA on the initial tuning run?
If the Siamese WG setup doesn't quite pan out you could probably install an additional pair of WGs pre-turbine (1 each port) and still realise the same performance goals you're shooting for. Would be a bitch to dial them in with the Siamese WG to get best efficiency.
Can you detail any port work you might be doing on the rebuild and expected gain from the work? Tempted by the PPRE Bridgeport?
If the Siamese WG setup doesn't quite pan out you could probably install an additional pair of WGs pre-turbine (1 each port) and still realise the same performance goals you're shooting for. Would be a bitch to dial them in with the Siamese WG to get best efficiency.
Can you detail any port work you might be doing on the rebuild and expected gain from the work? Tempted by the PPRE Bridgeport?
06-15-2015, 08:06 PM
#61
Awesome project, good luck with it. ETA on the initial tuning run?
If the Siamese WG setup doesn't quite pan out you could probably install an additional pair of WGs pre-turbine (1 each port) and still realise the same performance goals you're shooting for. Would be a bitch to dial them in with the Siamese WG to get best efficiency.
Can you detail any port work you might be doing on the rebuild and expected gain from the work? Tempted by the PPRE Bridgeport?
If the Siamese WG setup doesn't quite pan out you could probably install an additional pair of WGs pre-turbine (1 each port) and still realise the same performance goals you're shooting for. Would be a bitch to dial them in with the Siamese WG to get best efficiency.
Can you detail any port work you might be doing on the rebuild and expected gain from the work? Tempted by the PPRE Bridgeport?
Just rang them and it's gunna be a couple of weeks away before we start
. Shouldn't take more than a week to get all the fab work done ... then the fun starts.Doubt I will do much porting work on the rebuild ... maybe a polish of the runners . As far as the PPRE bridgeport goes - not something I would incorporate into a turbo build . BTW I might be doing the tune for that soon
06-17-2015, 08:03 PM
#63
Brettus, I worry about the large amount of heat the waste gate will see. If you plan on having the WG open as often as you are saying its going to get very hot. A traditional WG has an internal baffle made of silicone/nomex or some crap like that. You would be well past most WG's heat threshold. Synapse engineering makes a baffless WG in both 50 and 40mm. Another option would be a water cooled WG such as the offerings by TiAL.
06-18-2015, 01:37 AM
#64
Brettus, I worry about the large amount of heat the waste gate will see. If you plan on having the WG open as often as you are saying its going to get very hot. A traditional WG has an internal baffle made of silicone/nomex or some crap like that. You would be well past most WG's heat threshold. Synapse engineering makes a baffless WG in both 50 and 40mm. Another option would be a water cooled WG such as the offerings by TiAL.
The way I'm looking at mounting it , there wont be any pipes near the WG body plus it will get a lot of fresh air over it . I'm sure that will help .
Last edited by Brettus; 06-18-2015 at 02:14 AM.
06-18-2015, 04:59 PM
#65
sounds good. Why not take advantage of the the ability to use a dual spool turbine housing? It would help a good amount on such a large turbine. Any info or thoughts yet on your target piping and routing/sizing? As Team had mentioned this is a great opportunity to do some innovative work. I'm really looking forward to seeing things progress.
06-18-2015, 07:28 PM
#70
yeah ... been researching this ....http://www.rx7club.com/single-turbo-...l-flow-978453/
Older series setups go as low as 35mm ID and the ideal (spool vs peak power) is considered to be around 44mm ID .
BUT :
3x 35mm > 2x 44mm (2880 vs 2770mm2)
I also read that going larger than the turbo entry area was pointless ....... 35mm is only marginally smaller than the T3 divided flange size.
So it should be great for spoolup but I don't think it will be a penalty on the top end for my target whp.
AND ..... it will fit . the 42ID option wont.
Older series setups go as low as 35mm ID and the ideal (spool vs peak power) is considered to be around 44mm ID .
BUT :
3x 35mm > 2x 44mm (2880 vs 2770mm2)
I also read that going larger than the turbo entry area was pointless ....... 35mm is only marginally smaller than the T3 divided flange size.
So it should be great for spoolup but I don't think it will be a penalty on the top end for my target whp.
AND ..... it will fit . the 42ID option wont.
Last edited by Brettus; 06-18-2015 at 08:23 PM.
06-19-2015, 01:30 PM
#73
Pipe flow restriction is diameter x length relationship. If there isn't room for 42mm ID then it doesn't seem like there's room to make it equal length. Shorter is better IMO. Given the space you're only solution would be to make the rear port pipe longer.
But 35mm ID is close to the area of the smaller center port. So essentially the end ports are choking down to the center port size. At low rpm spooling up that should be good, but then may be too restrictive at high rpm/boost. Your power goal requires a lot of mass flow.
But 35mm ID is close to the area of the smaller center port. So essentially the end ports are choking down to the center port size. At low rpm spooling up that should be good, but then may be too restrictive at high rpm/boost. Your power goal requires a lot of mass flow.
06-19-2015, 03:44 PM
#74
Yeah , the only way for equal length is to make the rear pipe longer by about 250mm .
I think the SS heavy wall is actually more like 36ID (don't actually have a sample ATM)
so:
36.7mm pipe = 1058 (edit)
front and rear ports = 1080
centre port = 810
Turbo entry = 1130
It shouldn't be much of a restriction ... given that they don't have to flow any WG gases .
I think the SS heavy wall is actually more like 36ID (don't actually have a sample ATM)
so:
36.7mm pipe = 1058 (edit)
front and rear ports = 1080
centre port = 810
Turbo entry = 1130
It shouldn't be much of a restriction ... given that they don't have to flow any WG gases .
Last edited by Brettus; 08-01-2015 at 05:21 PM.
06-19-2015, 05:11 PM
#75
1.25" Std/Sch 40 pipe is 35mm ID, 42.2mm OD
Typically 1.50" Sch. 40 pipe is considered minimum ID for shared turbo/wastegate flow. It will come down to which one is more restricted; wastegate or turbo feed
Typically 1.50" Sch. 40 pipe is considered minimum ID for shared turbo/wastegate flow. It will come down to which one is more restricted; wastegate or turbo feed
Last edited by TeamRX8; 06-19-2015 at 05:13 PM.