965 heat exchanger solution?
02-09-2009, 11:48 AM
#16
Rennlist Member
My 3.6T with just a 1 bar spring B&B headers, stock cat and K27HF turbo showed about 3 years ago:
330rwtq @ 3300 rpms
300rwhp at 4000 rpms
Peak rwtq @ 5000 rpms
peak rwhp @ 5800 rpms.
When I did the cat bypass and muffler change I could tell power and torque is up considerably but have not had a chance to dyno it since. Using a 15% loss my car was seeing peak BHP at 430 or roughly 365 rwhp with cat using the numbers above. I figure it is closer to 450 now. I also find power delivery is a lot earlier and far more linear. I had some CIS leaks when the other numbers were recorded.
The only true way to tell BHP is to engine dyno you engine. But 15% loss is an acceptable number most commonly used. Also consider atmospheric conditions and type of dyno ed. My car was dynoed on a dynapack
02-12-2009, 05:09 PM
#18
Instructor
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Foot in mouth, sorry.
Killer Job, very creative.
I had assumed before looking closely that the merge was at a 45 degree angle to the other secondary.
It is gonna be a huge improvement over stock...
Killer Job, very creative.
I had assumed before looking closely that the merge was at a 45 degree angle to the other secondary.
It is gonna be a huge improvement over stock...
02-18-2009, 05:13 PM
#19
Pro
Thread Starter
its very deceving to look at but when you see the inside of the merge it looks very even
02-19-2009, 04:44 AM
#20
Burning Brakes
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Wow neat solution and nice job, looks really good and very interested about the final result!
I'm curious about the reason behind going with dual wastegates, avoiding the common overboost problem is obv a factor, but are there other advantages with a dual setup?
I'm curious about the reason behind going with dual wastegates, avoiding the common overboost problem is obv a factor, but are there other advantages with a dual setup?
02-20-2009, 10:02 AM
#22
Rennlist Member
More pics please.
BTW I understand the equal length of the pipes but why the long distance on the right side? I was told that you want to equalize the lengths of both sides from their mix point to minimize any imbalance. Also how is the lag? Wouldn't turning the pipes inward have helped to shorten the distance and still allow enough bend to minimize turbulence?
Last edited by cobalt; 02-20-2009 at 10:28 AM.
02-20-2009, 01:21 PM
#25
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When tuning the exhaust on a turbo engine, it's the positive pressure exhaust pulses arriving at the turbo which have the maximum impact on performance rather than the reflected negative pressure waves (that you would look to optimise on an N/A engine) returning from the collector. Shorter lengths are usually preferred because they loose less heat (and hence energy) from the exhaust gas before it arrives at the turbo.
With respect to the turbo flange detail, you should ideally re-work the shorter of the two secondary pipes so that you can use an evenly spliced pair of 90 degree bends for the feed into the turbo itself. Inside this pipe you would also weld in a divider wall to keep the left & right sides of the flow seperate. In doing this you will reduce the effective area of each side and make a "nozzle" to accelerate the flow at the turbine housing.
Secondly, it is then critical that the wastegate pipe is fed evenly from both sides of the engine, so the pipe has to be located centrally on the divider wall. Finally, the wastegate pipe must also be at less than 90 degrees to the direction of flow, otherwise you could get into a situation where the flow prefers to got through the turbo rather than down the wastegate pipe & the engine will boost creep. We had this situation on a customer's 965 once and only rectified it by changing the angle of the wastegate pipe on his US made headers. Obviously for MB911's system using twin wastegates is a better overall solution, however I thought I should mention it just in case anyone else is making their own single WG system or having creep problems with their bought in headers.
With respect to the turbo flange detail, you should ideally re-work the shorter of the two secondary pipes so that you can use an evenly spliced pair of 90 degree bends for the feed into the turbo itself. Inside this pipe you would also weld in a divider wall to keep the left & right sides of the flow seperate. In doing this you will reduce the effective area of each side and make a "nozzle" to accelerate the flow at the turbine housing.
Secondly, it is then critical that the wastegate pipe is fed evenly from both sides of the engine, so the pipe has to be located centrally on the divider wall. Finally, the wastegate pipe must also be at less than 90 degrees to the direction of flow, otherwise you could get into a situation where the flow prefers to got through the turbo rather than down the wastegate pipe & the engine will boost creep. We had this situation on a customer's 965 once and only rectified it by changing the angle of the wastegate pipe on his US made headers. Obviously for MB911's system using twin wastegates is a better overall solution, however I thought I should mention it just in case anyone else is making their own single WG system or having creep problems with their bought in headers.
02-21-2009, 12:08 AM
#26
Rennlist Member
When tuning the exhaust on a turbo engine, it's the positive pressure exhaust pulses arriving at the turbo which have the maximum impact on performance rather than the reflected negative pressure waves (that you would look to optimise on an N/A engine) returning from the collector. Shorter lengths are usually preferred because they loose less heat (and hence energy) from the exhaust gas before it arrives at the turbo.
With respect to the turbo flange detail, you should ideally re-work the shorter of the two secondary pipes so that you can use an evenly spliced pair of 90 degree bends for the feed into the turbo itself. Inside this pipe you would also weld in a divider wall to keep the left & right sides of the flow seperate. In doing this you will reduce the effective area of each side and make a "nozzle" to accelerate the flow at the turbine housing.
Secondly, it is then critical that the wastegate pipe is fed evenly from both sides of the engine, so the pipe has to be located centrally on the divider wall. Finally, the wastegate pipe must also be at less than 90 degrees to the direction of flow, otherwise you could get into a situation where the flow prefers to got through the turbo rather than down the wastegate pipe & the engine will boost creep. We had this situation on a customer's 965 once and only rectified it by changing the angle of the wastegate pipe on his US made headers. Obviously for MB911's system using twin wastegates is a better overall solution, however I thought I should mention it just in case anyone else is making their own single WG system or having creep problems with their bought in headers.
With respect to the turbo flange detail, you should ideally re-work the shorter of the two secondary pipes so that you can use an evenly spliced pair of 90 degree bends for the feed into the turbo itself. Inside this pipe you would also weld in a divider wall to keep the left & right sides of the flow seperate. In doing this you will reduce the effective area of each side and make a "nozzle" to accelerate the flow at the turbine housing.
Secondly, it is then critical that the wastegate pipe is fed evenly from both sides of the engine, so the pipe has to be located centrally on the divider wall. Finally, the wastegate pipe must also be at less than 90 degrees to the direction of flow, otherwise you could get into a situation where the flow prefers to got through the turbo rather than down the wastegate pipe & the engine will boost creep. We had this situation on a customer's 965 once and only rectified it by changing the angle of the wastegate pipe on his US made headers. Obviously for MB911's system using twin wastegates is a better overall solution, however I thought I should mention it just in case anyone else is making their own single WG system or having creep problems with their bought in headers.
Do you really think that the turbo will see evenly spaced exhaust pulses with that system, with the left feed pipe being so short?
Since the turbo has to be offset to one side it won't be possible to have evenly spaced pulses to the turbo and really it's not that much of a priority on a road car anyway as the turbo has to be packaged inside the rear bumper.
If a twin volute turbo was being used I could see utilizing a divided flange.
02-21-2009, 05:54 AM
#27
Burning Brakes
Colin, take a look at the picture that you posted.
Do you really think that the turbo will see evenly spaced exhaust pulses with that system, with the left feed pipe being so short?
Since the turbo has to be offset to one side it won't be possible to have evenly spaced pulses to the turbo and really it's not that much of a priority on a road car anyway as the turbo has to be packaged inside the rear bumper.
If a twin volute turbo was being used I could see utilizing a divided flange.
Do you really think that the turbo will see evenly spaced exhaust pulses with that system, with the left feed pipe being so short?
Since the turbo has to be offset to one side it won't be possible to have evenly spaced pulses to the turbo and really it's not that much of a priority on a road car anyway as the turbo has to be packaged inside the rear bumper.
If a twin volute turbo was being used I could see utilizing a divided flange.
https://rennlist.com/forums/993-turb...ber-two-3.html
02-21-2009, 08:39 AM
#28
Rennlist Member
I'd take Mr Belton's advice with a huge pinch of salt...his so called expertise has convinced several people on this board (one being a former boss of mine) to spend very large sums of money on big bhp engines that have subsequently blown up, twice. If you want the details look at this thread, especially from page 3 onwards:
https://rennlist.com/forums/993-turb...ber-two-3.html
https://rennlist.com/forums/993-turb...ber-two-3.html
Oh wow. I've just read 3 pages. Sounds like Schnele's saga (tuner blew up his engine twice and Schnele footed the bill both times; he's now on rebuild #3).
So, in England it's NineMeister; in the colonies it MotorMeister.
Last edited by Metal Guru; 02-21-2009 at 08:59 AM.
02-21-2009, 12:51 PM
#29
Burning Brakes
Yeah, the lecture about stuff I wasn't even talking about was a red flag in itself....
Oh wow. I've just read 3 pages. Sounds like Schnele's saga (tuner blew up his engine twice and Schnele footed the bill both times; he's now on rebuild #3).
So, in England it's NineMeister; in the colonies it MotorMeister.
Oh wow. I've just read 3 pages. Sounds like Schnele's saga (tuner blew up his engine twice and Schnele footed the bill both times; he's now on rebuild #3).
So, in England it's NineMeister; in the colonies it MotorMeister.
Don't worry, he'll p*ss of to another forum where he can show off his amazing ability to over promise and under deliver...
02-21-2009, 03:31 PM
#30
Rennlist Member
free speech rules here