2 piece E-shaft and carbon seals?
11-09-07, 04:37 AM
#26
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Its the morons that generally ask 'how high does it rev mate?'
You should aim to use as little revs as possible. Nothing should be dictating where you rev it to, other than the power band.
You should aim to use as little revs as possible. Nothing should be dictating where you rev it to, other than the power band.
11-09-07, 09:46 PM
#29
honestly, NRS seals are amazing with what they do. i really hope rich can chime in on this since he is putting them into my engine. but for what an e-shaft is worth, it would be more efficient to use those funds towards a single turbo, maybe a street port, LIM, PFS diff brace or something more useful to that affect. to be honest, you will not be ready for that e-shaft unless you are in the 3 rotor playing field or have maxed out every possible means of upgrades for your engine.
11-09-07, 11:39 PM
#30
maybe this guy wants to rev to 12k rpms for a greater purpose...did you ever think he may want to go single turbo. he'll be cranking out major hp for longer periods of time if thats the case.
plus if hp and torque dont drop to much after power band than steady power for longer period of time would be better. cant anyone do research before stating there opinion? if fd's peak power is somewhere around 6-6.5krpms, then why would they have it rev to 8k, use your heads
11-10-07, 01:24 AM
#31
Lives on the Forum
It's an NA engine, so unless it's got MONSTER ports there's no point, all this talk about turbos is irrelevant to what the OP was asking about. With a street port only it WILL drop off in power past 8k rpms, and will be making significantly less at 12k than it was at peak power.
Revving it higher becomes irrelevant once the power to the wheels in a higher gear surpasses what it would be if you kept it in the lower gear. By scaling a dyno plot to the gear ratios used you can find the optimum shift points.
Revving it higher becomes irrelevant once the power to the wheels in a higher gear surpasses what it would be if you kept it in the lower gear. By scaling a dyno plot to the gear ratios used you can find the optimum shift points.
11-10-07, 05:54 AM
#35
i looked up seting the power band for more power at higher rpms and this is what i found...
Power Band Tuning Considerations
The tuning of the power band is a great challenge. It is possible to create a peaky engine which generates more power from an engine if the manufacturer is willing to tune it for a very narrow power band. However, an engine with a narrow power band is more difficult to use. Such an engine must be coupled to a close-ratio transmission with many gears in order to remain in its power band while providing an acceptably wide range of output speeds. A flexible engine has a wide power band with less peak power, but could be tied to a less complex transmission with fewer gears and would not need to shift gears as often. Such an engine is also often called torquey because it maintains a more constant level of torque over a wider range of RPM.
[edit] Cost and Usage Considerations
Sports cars and other performance vehicles are generally designed for peak power in a narrow power band. In these vehicles, the higher cost of a complex transmission would be more acceptable, and the driver could be assumed to be more willing to shift gears often to remain in the power band. These vehicles attempt to achieve the greatest possible power to weight ratio, and benefit greatly from using a smaller engine tuned for high peak power rather than a large engine with a wide power band. Trucks and full-size cars are more often tuned for a wide power band and use larger engines to achieve acceptable power over a wide range. These vehicles have the benefit of not having to shift as often as vehicles with a narrow power band.
[edit] Tuning for high Horsepower Output or high Torque Output?
Since automobile shoppers rely heavily on the peak power output figure (typically given in horsepower or kilowatts), some auto makers tend towards producing "peaky" engines. For example, Honda's 2006 Civic Si's K20Z3 engine generates 197 hp (147 kW) at 7800 RPM. Though it produces a fairly flat torque curve compared to many engines, it only produces 139 ft·lbf (188 N·m) and it has relatively sharp (or "peaky") power delivery, this requires the driver to keep the engine at high RPM to extract the best performance from the Civic. In contrast, Volkswagen's 2006 GTI's 2.0T engine produces about 200 hp (149 kW) from 5,100 RPM to 6,000 RPM and a relatively flat torque band of 207 ft·lbf (281 N·m) from 1,800 to 5,000 RPM. This wide power delivery makes it easier for the driver to extract the vehicles best performance.
Power Band Tuning Considerations
The tuning of the power band is a great challenge. It is possible to create a peaky engine which generates more power from an engine if the manufacturer is willing to tune it for a very narrow power band. However, an engine with a narrow power band is more difficult to use. Such an engine must be coupled to a close-ratio transmission with many gears in order to remain in its power band while providing an acceptably wide range of output speeds. A flexible engine has a wide power band with less peak power, but could be tied to a less complex transmission with fewer gears and would not need to shift gears as often. Such an engine is also often called torquey because it maintains a more constant level of torque over a wider range of RPM.
[edit] Cost and Usage Considerations
Sports cars and other performance vehicles are generally designed for peak power in a narrow power band. In these vehicles, the higher cost of a complex transmission would be more acceptable, and the driver could be assumed to be more willing to shift gears often to remain in the power band. These vehicles attempt to achieve the greatest possible power to weight ratio, and benefit greatly from using a smaller engine tuned for high peak power rather than a large engine with a wide power band. Trucks and full-size cars are more often tuned for a wide power band and use larger engines to achieve acceptable power over a wide range. These vehicles have the benefit of not having to shift as often as vehicles with a narrow power band.
[edit] Tuning for high Horsepower Output or high Torque Output?
Since automobile shoppers rely heavily on the peak power output figure (typically given in horsepower or kilowatts), some auto makers tend towards producing "peaky" engines. For example, Honda's 2006 Civic Si's K20Z3 engine generates 197 hp (147 kW) at 7800 RPM. Though it produces a fairly flat torque curve compared to many engines, it only produces 139 ft·lbf (188 N·m) and it has relatively sharp (or "peaky") power delivery, this requires the driver to keep the engine at high RPM to extract the best performance from the Civic. In contrast, Volkswagen's 2006 GTI's 2.0T engine produces about 200 hp (149 kW) from 5,100 RPM to 6,000 RPM and a relatively flat torque band of 207 ft·lbf (281 N·m) from 1,800 to 5,000 RPM. This wide power delivery makes it easier for the driver to extract the vehicles best performance.
11-11-07, 11:05 AM
#36
Full Member
Thread Starter
i looked up seting the power band for more power at higher rpms and this is what i found...
[edit] Cost and Usage Considerations
Sports cars and other performance vehicles are generally designed for peak power in a narrow power band. These vehicles attempt to achieve the greatest possible power to weight ratio, and benefit greatly from using a smaller engine tuned for high peak power rather than a large engine with a wide power band. Trucks and full-size cars are more often tuned for a wide power band and use larger engines to achieve acceptable power over a wide range. These vehicles have the benefit of not having to shift as often as vehicles with a narrow power band.
.
[edit] Cost and Usage Considerations
Sports cars and other performance vehicles are generally designed for peak power in a narrow power band. These vehicles attempt to achieve the greatest possible power to weight ratio, and benefit greatly from using a smaller engine tuned for high peak power rather than a large engine with a wide power band. Trucks and full-size cars are more often tuned for a wide power band and use larger engines to achieve acceptable power over a wide range. These vehicles have the benefit of not having to shift as often as vehicles with a narrow power band.
.
Thank you for some good feedback.
To all those who are insulting and criticising before reading properly, this is a LOTUS 7, weight is 550kg...
Thus power to weight ratio is a big factor.
A turbo is not neccesary for this type of car, please read and then think before replying.
11-11-07, 11:20 AM
#37
Full Member
Thread Starter
So what kind of motors do you think rotaries are? How strong is your FD at 4k rpm?... They are not torquey motors.
You just contradicted yourself, superbikes are setup for high rpm power, and you said cruisers are setup for low rpm power, so what type of car do you think this lotus is? It's definately not a cruiser fool, read my first msg, dominantly race car...
Dont be so ignorant and unhelpful if you are going to post.
11-11-07, 01:38 PM
#38
2/4 wheel cornering fiend
Yes, there is reason to rev NA engines higher. That said, as Black91n/a stated, volumetric efficiency includes porting, intake, and exhaust, and with any engine design, there's a point of diminishing returns with regards to ever-higher rpms and internal friction, as well as powerband (your torque curve becomes increasingly spikey, making the engine harder to use without compromises...and that includes both roadrace circuit and dragrace). I'm not so sure that a NA rotary that revs to 12K would be all that driveable...
And not to go off-topic here, but turbocharged engines aren't high revvers like NA engines, because once forced induction systems achieve the beginning of their efficiency curve, they realize their biggest benefits the longer the intake cycle is open. As rpms rise and the intake cycle becomes shorter and shorter, the decreasing amount of time to fill the combustion chamber becomes much more of an issue than it is for NA engines.
11-11-07, 11:38 PM
#39
I don't think anyone is actually suggesting running an engine at 12K is going to be a productive venture. That number comes from the manufacturers claim of it's abilities. From what I've seen, people run these on PP cars in much more reasonable RPM ranges, but still quite a bit higher than stock.
You need to read up on peripheral port motors...
You need to read up on peripheral port motors...
11-11-07, 11:44 PM
#40
honestly, NRS seals are amazing with what they do. i really hope rich can chime in on this since he is putting them into my engine. but for what an e-shaft is worth, it would be more efficient to use those funds towards a single turbo, maybe a street port, LIM, PFS diff brace or something more useful to that affect. to be honest, you will not be ready for that e-shaft unless you are in the 3 rotor playing field or have maxed out every possible means of upgrades for your engine.
B. This is a 2 rotor e-shaft we're talking about here. It is not 2-piece simply for strength, but to allow for a center bearing to lighten the effects of higher-than-stock RPM shaft flex. This allows for less clearancing, resulting in better performance.
