UMW Stage 2
10-26-2008, 03:28 AM
#16
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It's taken me a while to finally clue into what the Motronic ecu is doing by controlling boost and its benefits. I've read a lot of posts and asked a number of people. On the surface, Kevin saying that the larger stage 2 won't help if you have a ebc vs a stage 1 with ebc, may not seem right, but it actually makes sense. If you look at Dyno graphs of Motronic boost controlled cars and ebc cars it helps...
I'll try to explain with a simplified example (pls someone correct me if I'm wrong).
Say you believe that max boost your engine will tolerate is 1.1 bar at maximum torque - say 4500 rpm. So with a ebc set at 1.1 bar, and stage 1 turbos, your engine may reach 1.1 bar say at 3000rpm and maintain that through peak torque ie 4500 rpm and up to red line at 1.1 bar. The stage 1 turbos can maintain the 1.1 bar without difficulty.
If you have stage 2 turbos and an ebc (max boost engine will tolerate at max torque is the same 1.1 bar at 4500rpm). So, with larger turbos, you may not reach 1.1 bar until 3500 rpm (ie some lag), you have 1.1 at 4500 rpm and also up to redline...What's happened is you have lost out on the 1.1 boost from 3000 to 3500 in this example....less power under the curve....
If you were running the Motronic ecu and allowing it to control boost with proper programing, and same condition of 1.1 bar max at max torque 4500 rpm.. With Stage 1 turbos, hit 1.1 bar at 3000 rpm, 1.1 bar at 4500 rpm, but also see 1.2 bar at 5000 up to redline (the 1.2 bar is safe after max torque is exceeded). With stage 2 turbos, and programing, you may see 1.1 bar at 3500 rpm, 1.1 at 4500 rpm and from 5000-6000 see 1.3 bar (also safe because it's past max torque) and get more area under the curve/extra hp higher up in rpm range.
The above explanation does not take into account the 'efficiency' of turbochargers and heat generated by smaller turbos, so it is more complicated. The stage 2 turbos may also give a little denser air/less heat than stage 1 (but may be not enough difference to overcome the rpm difference of my example with ebc, and also helping to allow higher boost in the stage 2 Motronic controlled engine).
hope this helps someone...
Ryojo
I'll try to explain with a simplified example (pls someone correct me if I'm wrong).
Say you believe that max boost your engine will tolerate is 1.1 bar at maximum torque - say 4500 rpm. So with a ebc set at 1.1 bar, and stage 1 turbos, your engine may reach 1.1 bar say at 3000rpm and maintain that through peak torque ie 4500 rpm and up to red line at 1.1 bar. The stage 1 turbos can maintain the 1.1 bar without difficulty.
If you have stage 2 turbos and an ebc (max boost engine will tolerate at max torque is the same 1.1 bar at 4500rpm). So, with larger turbos, you may not reach 1.1 bar until 3500 rpm (ie some lag), you have 1.1 at 4500 rpm and also up to redline...What's happened is you have lost out on the 1.1 boost from 3000 to 3500 in this example....less power under the curve....
If you were running the Motronic ecu and allowing it to control boost with proper programing, and same condition of 1.1 bar max at max torque 4500 rpm.. With Stage 1 turbos, hit 1.1 bar at 3000 rpm, 1.1 bar at 4500 rpm, but also see 1.2 bar at 5000 up to redline (the 1.2 bar is safe after max torque is exceeded). With stage 2 turbos, and programing, you may see 1.1 bar at 3500 rpm, 1.1 at 4500 rpm and from 5000-6000 see 1.3 bar (also safe because it's past max torque) and get more area under the curve/extra hp higher up in rpm range.
The above explanation does not take into account the 'efficiency' of turbochargers and heat generated by smaller turbos, so it is more complicated. The stage 2 turbos may also give a little denser air/less heat than stage 1 (but may be not enough difference to overcome the rpm difference of my example with ebc, and also helping to allow higher boost in the stage 2 Motronic controlled engine).
hope this helps someone...
Ryojo
Last edited by Basal Skull; 10-26-2008 at 11:12 AM. Reason: edited
10-26-2008, 03:45 PM
#17
Stage 2 is larger and has more output than Stage one.. Larger turbochargers, more fueling. However, as I told you, if you are going to run a EBC there is no sense in upgrading because your output will be less. Put another way, the ECU is tuned for specific load and boost control it is not constant. It will deliver "X" amount of boost for a specific load and RPM and will raise and lower boost where a EBC cannot.
If you run your EBC set at 1bar.. You are missing the torque benifits with the programmed boost control. If you set your EBC to 1.3 bars, you risk engine damage going thru peak torque with those levels of boost. Again what I am saying is, the Motronic ECU does a better job and dialing out the boost requirements to maximize requested output vs having a EBC do it.
If you run your EBC set at 1bar.. You are missing the torque benifits with the programmed boost control. If you set your EBC to 1.3 bars, you risk engine damage going thru peak torque with those levels of boost. Again what I am saying is, the Motronic ECU does a better job and dialing out the boost requirements to maximize requested output vs having a EBC do it.
10-27-2008, 09:20 AM
#18
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Ryojo, great synopsis.
I gather that the larger K16/26 turbos can and will provide boost up to 1.2 or 1.3 Bar as determined by the Monotonic, influenced nevertheless, by the physical limitations of the turbo to provide the boost at a given rpm, the specific Monotronic program tables, IATs and the octane of the fuel being used. Kevin has frequently advocated using the highest rated fuel you can get so as to minimize heat related programed retardation. At the same time, boost will be reduced and timing retarded if combustion conditions are unfavourable for whatever reason, thus protecting the engine from detonation etc. (A very valuable safety feature of the Monotronic Vs Fixed Boost Control). Thus, oportunity exists for significant periods when boost will be safely in the 1.0-1.3 Bar range, permitting a better outcome than with fixed boost it might be suggested. Phelix has postulated that when high boost is maintained say in a Vmax type activity, this high boost can result in heat soak, and significant Monotronic timing retardation, negating or diminishing the benefit of the higher boost on offer. How that extends to street, mountain road, or track applications remains unclear to me at least. So much depends on your intended application. You can see how an F1 team can spend the equivalent of the GDP of a small 3rd world country sorting this out and gaining all of few tenths in lap time!
In any case, your explanation helps me understand how the performance of the smaller turbos would be the same or even greater than the larger units, if the boost was fixed at a level that the smaller units could deliver.
As for the power output of the Stage 2, my expectation was somewhere between 460-480hp depending on fuel, temp etc. The potentially mathematically flawed calculation of HP from the 3rd gear run in fact comes out at 470hp, (17.5% gain)whilst the TQ comes out at 440lb ft. The 470 -480 mark is about where others on this forum such as Phelix have placed it, in keeping with expectation. A 60--130 time would shed some light also.
I gather that the larger K16/26 turbos can and will provide boost up to 1.2 or 1.3 Bar as determined by the Monotonic, influenced nevertheless, by the physical limitations of the turbo to provide the boost at a given rpm, the specific Monotronic program tables, IATs and the octane of the fuel being used. Kevin has frequently advocated using the highest rated fuel you can get so as to minimize heat related programed retardation. At the same time, boost will be reduced and timing retarded if combustion conditions are unfavourable for whatever reason, thus protecting the engine from detonation etc. (A very valuable safety feature of the Monotronic Vs Fixed Boost Control). Thus, oportunity exists for significant periods when boost will be safely in the 1.0-1.3 Bar range, permitting a better outcome than with fixed boost it might be suggested. Phelix has postulated that when high boost is maintained say in a Vmax type activity, this high boost can result in heat soak, and significant Monotronic timing retardation, negating or diminishing the benefit of the higher boost on offer. How that extends to street, mountain road, or track applications remains unclear to me at least. So much depends on your intended application. You can see how an F1 team can spend the equivalent of the GDP of a small 3rd world country sorting this out and gaining all of few tenths in lap time!
In any case, your explanation helps me understand how the performance of the smaller turbos would be the same or even greater than the larger units, if the boost was fixed at a level that the smaller units could deliver.
As for the power output of the Stage 2, my expectation was somewhere between 460-480hp depending on fuel, temp etc. The potentially mathematically flawed calculation of HP from the 3rd gear run in fact comes out at 470hp, (17.5% gain)whilst the TQ comes out at 440lb ft. The 470 -480 mark is about where others on this forum such as Phelix have placed it, in keeping with expectation. A 60--130 time would shed some light also.
Last edited by malcolmd; 10-27-2008 at 09:25 AM. Reason: typo
10-27-2008, 12:09 PM
#19
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Yes, once you have your car broken in, you'll see 1.3 and perhaps a little more briefly in the upper rpms in 4th gear. Runs really well...I think the turbos themselves are capable of producing quite a bit more than that and the ecu is keeping things under control. And like other people have said, it's not just the HP/Tq numbers but also the area under the curve.
(a little hard on the pocket book but what a great hobby - eh?!
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(a little hard on the pocket book but what a great hobby - eh?!
)
10-27-2008, 06:45 PM
#20
A question for the US UMW stage 2 users.
I rarely get to drive my car - 1000 miles in 10 months and I've just 'noticed' something that could be psychological:
When flooring it in 3rd from low revs, sometimes the car roars, squats and goes. Other times the distinctive roar (compressor/induction noise apparently) isn't there although the acceleration is probably the same.
When cruising in fifth/sixth gear at 2500rpm and then flooring it, boost builds with a nice push or torque but I can feel a 'fluttering' at around 3500-4000rom that I think is just the wastegates doing there thing. This is only noticeable in the higher gears.
I would say the only real 'problem' as such I have with the kit is that it's so damn smooth!
I rarely get to drive my car - 1000 miles in 10 months and I've just 'noticed' something that could be psychological:
When flooring it in 3rd from low revs, sometimes the car roars, squats and goes. Other times the distinctive roar (compressor/induction noise apparently) isn't there although the acceleration is probably the same.
When cruising in fifth/sixth gear at 2500rpm and then flooring it, boost builds with a nice push or torque but I can feel a 'fluttering' at around 3500-4000rom that I think is just the wastegates doing there thing. This is only noticeable in the higher gears.
I would say the only real 'problem' as such I have with the kit is that it's so damn smooth!
10-27-2008, 06:53 PM
#21
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Ace, you have to realize that>> going into peak torque the ECU has to adjust boost according to LOAD (which is higher in th and 6th) temperature and octane (knock).. It is going to be a fluid situation. The wastegates are working overtime at 4000RPM's.. As the RPM increases the engine requirements for air increases>>which in turn will use more of the turbochargers output vs 3500 to 4000 RPM's..
Smooth power delivery is what we want..
Smooth power delivery is what we want..
10-27-2008, 06:58 PM
#22
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I probably haven't had enough time with the package to pick up the various nuances. I'm still a little tentative with it too.
I do know what you mean by the "roar" as boost builds at higher RPM though! I'll watch out for your phenomenon.
What I have noticed, as mentioned by we both, is the amazingly smooth delivery of the acceleration - incredibly linear I think.
Malcolm
I do know what you mean by the "roar" as boost builds at higher RPM though! I'll watch out for your phenomenon.
What I have noticed, as mentioned by we both, is the amazingly smooth delivery of the acceleration - incredibly linear I think.
Malcolm
10-27-2008, 07:03 PM
#23
Ace, you have to realize that>> going into peak torque the ECU has to adjust boost according to LOAD (which is higher in th and 6th) temperature and octane (knock).. It is going to be a fluid situation. The wastegates are working overtime at 4000RPM's.. As the RPM increases the engine requirements for air increases>>which in turn will use more of the turbochargers output vs 3500 to 4000 RPM's..
Smooth power delivery is what we want..
Smooth power delivery is what we want..
It feels to me that now the turbos have loosened up a bit they're delivering the boost earlier than they did before. There's definitely a reduction in abruptness of initial boost delivery which could be interpreted as down on power when it's probably just being smoother :S
10-27-2008, 07:13 PM
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Ace, you can increase the power by bolting on a new Secan IC or running down to your local paint store and filling your tank with some Toluene..
10-27-2008, 07:19 PM
#25
I'm thinking fuel as I the last time I felt this 'flutter' at 3500rpm I had been cruising at 70mph for a long period at 5 degrees celcius. This doesn't feel like an inlet heat issue. Probably not an issue at all.
10-28-2008, 11:47 AM
#26
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MDavidson, your data seems very reliable as it is close to other findings and seems to be repetitive. However you will have to do a certain correction to speed, as it is calculated through Gs and vehicle data, so you might have a 5% miss there, same as speedo.
Phelix's run was 5.9 seconds from 60-110mph, that is about 0.2 seconds faster than yours, which is probably a 0.3s difference when corrected, not much, maybe equivalent to 20hp resulting from weight, tire sizes, slope or anything else.. According to the data recorded, his Hp output hovers around 470hp.
A lot of data in this thread, sorry to be quoting but it makes for easier reading.
Mdavidson, knock sensors are there to protect against detonation on these engines, you need to go really crazy on the boost front to blow your engine. There are instances where I have felt performance drop significantly in very hot weather at 270kph+, I am sure timing was being retarded quite aggressively, I run pump fuel always, even at the track. Your risk is when you run without knock control or with poor programming, which is not the case here..As to opportunity loss of performance without overboost, please see below at the end of this post, 400RPMs worth of 1.3 bar will not make a recordable performance difference.
Phelix had faster times at VMAX with his 430bhp stock K16 setup seeing peaks of 1.2 Bar for a few tenths, vs. the Stage 2 with larger turbos, the small turbos seem to be holding well against heat soak with good programming. 1.2 bar is certainly beyond the threshold of efficiency for stock units, but due to the short period of time it is staying there, IATs are under control.
Data from Phelix’s Stage 2 runs:
- Peak torque happens at slightly less than 1 Bar with this programming,
- Peak Hp is achieved at less than 1.1 Bar.
- Boost does not go below 1 Bar throughout the run from peak torque upwards
- Overboost from 1.0 to 1.3 bar happens throughout only circa 400RPMs (0.6s in 4th gear)
Net net from the above, an EBC set at 1.0-1.1 bar will not compromise torque, HP, performance or engine longevity IMO.
Phelix's run was 5.9 seconds from 60-110mph, that is about 0.2 seconds faster than yours, which is probably a 0.3s difference when corrected, not much, maybe equivalent to 20hp resulting from weight, tire sizes, slope or anything else.. According to the data recorded, his Hp output hovers around 470hp.
A lot of data in this thread, sorry to be quoting but it makes for easier reading.
At the same time, boost will be reduced and timing retarded if combustion conditions are unfavourable for whatever reason, thus protecting the engine from detonation etc. (A very valuable safety feature of the Monotronic Vs Fixed Boost Control). Thus, oportunity exists for significant periods when boost will be safely in the 1.0-1.3 Bar range, permitting a better outcome than with fixed boost it might be suggested. .
However, as I told you, if you are going to run a EBC there is no sense in upgrading because your output will be less. Put another way, the ECU is tuned for specific load and boost control it is not constant. It will deliver "X" amount of boost for a specific load and RPM and will raise and lower boost where a EBC cannot.
If you run your EBC set at 1bar.. You are missing the torque benifits with the programmed boost control. .
If you run your EBC set at 1bar.. You are missing the torque benifits with the programmed boost control. .
- Peak torque happens at slightly less than 1 Bar with this programming,
- Peak Hp is achieved at less than 1.1 Bar.
- Boost does not go below 1 Bar throughout the run from peak torque upwards
- Overboost from 1.0 to 1.3 bar happens throughout only circa 400RPMs (0.6s in 4th gear)
Net net from the above, an EBC set at 1.0-1.1 bar will not compromise torque, HP, performance or engine longevity IMO.
10-28-2008, 11:50 AM
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With stage 2 turbos, and programing, you may see 1.1 bar at 3500 rpm, 1.1 at 4500 rpm and from 5000-6000 see 1.3 bar (also safe because it's past max torque) and get more area under the curve/extra hp higher up in rpm range.
The above explanation does not take into account the 'efficiency' of turbochargers and heat generated by smaller turbos, so it is more complicated. The stage 2 turbos may also give a little denser air/less heat than stage 1
Ryojo
The above explanation does not take into account the 'efficiency' of turbochargers and heat generated by smaller turbos, so it is more complicated. The stage 2 turbos may also give a little denser air/less heat than stage 1
Ryojo
Peak torque on the Stg 2 occurs around 5,700RPms in 4th gear under load at 1.05 bar
Smaller turbo compressors will give more linearity and earlier peak torque in the RPM range. They can also deliver higher absolute peak torque than the larger units if they are properly tuned and even higher HP if they have modified camshafts.
- The limit for a non "cammed" engine seems to be sub-500bhp.
- You can go above 520bhp without any head work at all, and 600+ without porting and polishing, but you will need springs, sealing etc..
With a 5 bar FPR, you can go very safely to 520FWHP. Once you factor chassis dyno optimism, you can add maybe 15% to these numbers and be very safe.
10-28-2008, 06:39 PM
#28
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Thanx for the clarification and numbers, Jean. I'm going to start collecting info and get my self a proper datalogger so I don't have to make them up in my head... sure is fun/I enjoy thinking about this stuff though.
10-29-2008, 07:01 AM
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Jean, great post and thanks for the time and effort, passing the information on. 
This is what is so great about this forum. Knowledgable people, contribute so freely, and the discourse is always in good spirit.
In showing the speed/time data, I was aiming to simply display the change in slope (acceleration) between Stock and Stage 2 in a qualitative maner, and not put too much emphasis on the actual speed and times because of the limitations of the technology (although these infact do look believable "within a few tenths"). Another factor that I had not mentioned in oversight, is that the stock runs were on OEM 18's, whereas the Stage 2 run was on the Champion 19s with 30 series tyres not 25's. This explains the slightly higher speed at the gear changes and may account for slightly slower times, say cw Phelix's.
It would be nice to see a side by side graph of Stock, Stage 1, and Stage 2. As for the Stage 3, I've not read of anyone with it.
This is what is so great about this forum. Knowledgable people, contribute so freely, and the discourse is always in good spirit.
In showing the speed/time data, I was aiming to simply display the change in slope (acceleration) between Stock and Stage 2 in a qualitative maner, and not put too much emphasis on the actual speed and times because of the limitations of the technology (although these infact do look believable "within a few tenths"). Another factor that I had not mentioned in oversight, is that the stock runs were on OEM 18's, whereas the Stage 2 run was on the Champion 19s with 30 series tyres not 25's. This explains the slightly higher speed at the gear changes and may account for slightly slower times, say cw Phelix's.
It would be nice to see a side by side graph of Stock, Stage 1, and Stage 2. As for the Stage 3, I've not read of anyone with it.
10-29-2008, 03:53 PM
#30
Thanks for the info Jean. You seem to always have facts to back your statements and it always seems to be relevant and helpful tid-bits.
Just as an fyi...I think Kevin's stuff is excellent....and Gunther's programming excellent. My challenge was getting the car to work good in the hills (2nd gear stuff) and on the highway. The EBC allowed me to do that and I am very happy w/the results. For the hills I run a 1.2 program and the highway a 1.0 program. Those seem to work best w/the different load the motor sees in those two different environments. I run on mixed fuel as the 91 here in Cali is junk. I also had the rod bolts and head studs done on my car so not too worried about that issues if there is an over boost. The car has seen as much as 1.3 bar w/no noticable fall off in performance. In cool air up on Muholland at 1.2 bar, its simply killer...w/no lag whatsoever. I think if I were doing more high speed highway stuff the 16/26 might be a good choice, but the spool on the 16/24's is remarkably almost "instant-on". Who knows....A lot of $$ to upgrade to see if I'm right or wrong. All in all, very happy w/the kit I have.
Just as an fyi...I think Kevin's stuff is excellent....and Gunther's programming excellent. My challenge was getting the car to work good in the hills (2nd gear stuff) and on the highway. The EBC allowed me to do that and I am very happy w/the results. For the hills I run a 1.2 program and the highway a 1.0 program. Those seem to work best w/the different load the motor sees in those two different environments. I run on mixed fuel as the 91 here in Cali is junk. I also had the rod bolts and head studs done on my car so not too worried about that issues if there is an over boost. The car has seen as much as 1.3 bar w/no noticable fall off in performance. In cool air up on Muholland at 1.2 bar, its simply killer...w/no lag whatsoever. I think if I were doing more high speed highway stuff the 16/26 might be a good choice, but the spool on the 16/24's is remarkably almost "instant-on". Who knows....A lot of $$ to upgrade to see if I'm right or wrong. All in all, very happy w/the kit I have.