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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Fri May 04, 2012 10:54 pm 
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Joined: Sat Nov 12, 2011 6:24 pm
Posts: 96
Location: Montreal, Canada
ECU Model: S100 Pro
Firmware Version: 61
The "massive voltage fluctuations" you're aluding to aren't even near that Steve :lol:. I get 11.5 to 12 volts idling at 1150RPM and a healthy and steady 14+ volts anywhere over 2K RPM.
Forget the street car needs, how much time do you think you spend below 2k in a 3.2L inline six race car that revs to 8K?
The whole reliability thing just doesn't make much sense to me either. Turning accesories slower, like Ignitionautosport mentions, ADDS reliability to these systems (at least in a racing environment) it doesn't take any away. On a 2:1 ratio (stock alternator gearing) at 8K the alternator is spinning at 16k. If I reduce the ratio to 1:1 I've cut the alts speed in half! How could this be detrimental to reliability given that the car spends 95% of it's life above the 2K RPM that gives me the steady 14V you all seem to find so important? Trust me, I know I need the strongest voltage possible but as mentioned I've got it where/when it counts. Same goes for the water pump and power steering pump (if I had one...).


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Fri May 04, 2012 11:22 pm 
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Joined: Sat Nov 12, 2011 6:24 pm
Posts: 96
Location: Montreal, Canada
ECU Model: S100 Pro
Firmware Version: 61
Hard to say, I guess it depends on how much money you want to spend. A short while ago, Alex (DTAS54) had Chuck Stickley quote him on a knife edged S54 crank and we both fell on our asses when he got the price . If I remember correctly it was over 2k for roughly the same amount of power a good set of pulleys will give you .
Windage trays are cheap but better at controlling oil aeration than producing noticeable gains.
Slightly off topic but does anybody remember how Mazda got in sooo much trouble when they falsely advertised the (then new) RX8 as having 250hp when in fact you couldn't dyno one above the 230ish mark?! . Maybe they disconnected all the belts and ran the engine stripped as mentioned by VR6Turbo...

VR6Turbo wrote:
ignitionautosport wrote:
And yes, quite right about the parasitic loss though charging - if you want to see, give an alternator full field and see if you can turn the pulley by hand. Feels rock solid.


On parasitic losses in general, is there much gain in knife edged cranks, windage trays etc etc?

Out of interest, when OEMs dyno their engines, do they measure the power in full road trim, or do they just strap it to the bench tester with no alternator or pumps etc? I've seen pictures and videos of bench testing and some of them have no accessories and the intake and exhausts are obviously radically different to what the engine will see in the car.


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Fri May 04, 2012 11:27 pm 
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Joined: Fri Jul 29, 2011 9:08 pm
Posts: 30
stevieturbo wrote:
I'm certainly not a convert. It's obvious various things have drive loads, friction, whatever.....Not a chance. I certainly wouldnt want a system that had massive voltage fluctuations, nor would any professional race team

See next note....

On a serious note, I appreciate the heads up that going to an HTD belt system would be even better at reducing parasitic losses, and there is no reason (other than the OBVIOUS ie avoid loss of reliability) that I can't do both at the same time.

The intent of this forum I believe is to provide a platform for useful exchange of information to help people in the DTA community manage their engines. Although I've become expert and even Board Certified in one field, that of Obstetrics and Gynecology, I am not under the illusion that I am expert in the field of engine management.....so I really appreciate input from everyone (contrarians included) when I post in here. I hope to benefit from people's experience in the forum on engine management issues, and whenever I feel I can give back in any way, I'll be very quick to do so.


Last edited by DTAS54 on Sat May 05, 2012 1:24 am, edited 1 time in total.

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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 1:21 am 
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Joined: Fri Jul 29, 2011 9:08 pm
Posts: 30
10 years ago in a hypothetical forum.....

Steve: I want to use a DTA to turbocharge my engine in a reliable fashion.
Alex: Don't do it, it could be unreliable.
Steve: But I think I could make more power.
Alex: You could make more power.
Steve: So you are a convert?
Alex: No, it might not be reliable.

Steve: Shrug, I thought the whole point was to use DTA to make it reliable?

Might as well have fun with this....


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 6:33 am 
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Joined: Wed Jul 27, 2011 5:30 am
Posts: 570
Location: New Zealand
ECU Model: S80 Pro
Well said.
DTAS54 wrote:
The intent of this forum I believe is to provide a platform for useful exchange of information to help people in the DTA community manage their engines.
-{snip}-
I hope to benefit from people's experience in the forum on engine management issues, and whenever I feel I can give back in any way, I'll be very quick to do so.

_________________
| '94 GSR Lancer | '96 Toyota Carib 20V | '83 Toyota Starlet | www.ignitionautosport.co.nz and also on Google+ |


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 9:16 am 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2882
Location: Norn Iron
ECU Model: No ECU
DTAS54 wrote:
10 years ago in a hypothetical forum.....

Steve: I want to use a DTA to turbocharge my engine in a reliable fashion.
Alex: Don't do it, it could be unreliable.
Steve: But I think I could make more power.
Alex: You could make more power.
Steve: So you are a convert?
Alex: No, it might not be reliable.

Steve: Shrug, I thought the whole point was to use DTA to make it reliable?

Might as well have fun with this....


Not even close the what this discussion is about.

Would I fit a turbocharger to an engine in the hope of only making 3-4bhp ? No way
I fit one in the aim of doubling, trebling, quadrupling or more the factory power levels. Naturally there is a risk of less reliability there if not build correctly.
So is that risk worth it for the potential gains ? Absolutely.


My issue is simply down to going to quite extensive measures only to yield maybe 3-4bhp under certain circumstances. I just dont feel it is worth the effort, unless all other avenues of power release have already been exhausted

The fact this has caused running issues, means it is compromised. Perhaps an easier solution for Simon is just to install a better ignition system. If he is seeing a genuine 11-12v, then there really should be no issue at all with spark performance even with low dwell times. SO it would almost lead me to think there is an actual problem other than running at 12v.
If an ignition system can start the car whilst cranking, which could be as low as 8-9v, then running at low load with 12v should be very very easy.

I'm not knocking anyone for going down the route of trying to reduce drive loads. Each to their own, and Ive already said it has some merit. Would I be bothered doing it myself ? Nope.
I want to ensure my fuel system, ignition system and every electrical device in my car has a good reliable source of power at all times, as well as enough surplus to keep the battery fully charged.

Even with the battery. I have tried a small race battery, and it does start the car fine. But if you had a technical issue and needed to crank the engine over for any length of time, or run cooling fans etc etc will a small race battery offer this sort of performance ?
Nope. So for me it isnt worth the risk using one.

There are of course many other areas to consider if talking about parasitic losses.

Tyres, Wheels, suspension geometry, driveshafts, bearings, gears, gear oil, clutch, flywheel, engine oil etc.

Again all of these could be tweaked to offer as little friction or resistance as possible, reduce weight and hopefully transfer the power more efficiently to the ground.


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 10:30 am 
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Joined: Sat Nov 12, 2011 6:24 pm
Posts: 96
Location: Montreal, Canada
ECU Model: S100 Pro
Firmware Version: 61
stevieturbo wrote:
The fact this has caused running issues, means it is compromised. Perhaps an easier solution for Simon is just to install a better ignition system. If he is seeing a genuine 11-12v, then there really should be no issue at all with spark performance even with low dwell times. SO it would almost lead me to think there is an actual problem other than running at 12v.
If an ignition system can start the car whilst cranking, which could be as low as 8-9v, then running at low load with 12v should be very very easy.

Just to be clear on this; my car runs fine. It starts easily, idles fine and runs without any issues whatsoever. My whole reason for asking about the batt compensation table was to find out what others were doing with it and how to set it up. I knew my idle voltage was "lower" than 13-14V because of the pulleys I use and I wanted (still want) to maybe use this to "fine tune" the ignition portion of the map.
And, TBH, we had a peek at someone elses map from a different ECU (same engine though) and saw he was using it and it got us thinking... Hope I didn't open up another can of worms with this last statement. :(


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 12:21 pm 
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Joined: Tue Aug 09, 2011 2:54 pm
Posts: 318
Location: Stevenage
ECU Model: S80 Pro
Distributor: Roverdose
generally speaking, i can see the theory of slowing the alternator down to keep it reliable, but surely your not making any more power if the electrical system isnt powerful enough to run the engine properly?.

why not find an alternator that can run at a lower speed and still provide the correct voltages?

the pulley on my mg zs is quite small, off hte top of my head maybe 2" diam, something like that not suit the engine better?

Drew


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 12:50 pm 
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Joined: Fri Jul 29, 2011 9:08 pm
Posts: 30
stevieturbo wrote:
My issue is simply down to going to quite extensive measures only to yield maybe 3-4bhp under certain circumstances. I just dont feel it is worth the effort, unless all other avenues of power release have already been exhausted


Swapping pulleys and activating an existing feature are extensive measures?


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 Post subject: Re: Parasitic reduction: Pro/Con
PostPosted: Sat May 05, 2012 12:50 pm 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2882
Location: Norn Iron
ECU Model: No ECU
Simon P. wrote:
stevieturbo wrote:
The fact this has caused running issues, means it is compromised. Perhaps an easier solution for Simon is just to install a better ignition system. If he is seeing a genuine 11-12v, then there really should be no issue at all with spark performance even with low dwell times. SO it would almost lead me to think there is an actual problem other than running at 12v.
If an ignition system can start the car whilst cranking, which could be as low as 8-9v, then running at low load with 12v should be very very easy.

Just to be clear on this; my car runs fine. It starts easily, idles fine and runs without any issues whatsoever. My whole reason for asking about the batt compensation table was to find out what others were doing with it and how to set it up. I knew my idle voltage was "lower" than 13-14V because of the pulleys I use and I wanted (still want) to maybe use this to "fine tune" the ignition portion of the map.
And, TBH, we had a peek at someone elses map from a different ECU (same engine though) and saw he was using it and it got us thinking... Hope I didn't open up another can of worms with this last statement. :(


Ahh right, I thought you were saying you were having difficulties running the engine, and you hoped a longer dwell might resolve it.

Really it's easy....if there are no running problems, then you dont need to change anything. If the spark is adequate to run the engine with no missfires, then there isnt really a lot of point increasing the dwell.

I dont bother with the dwell compensation, I just run a fixed dwell.

Some engines/coils will run fine with only around 3ms of dwell, others might take as much as 6ms. Or some might even be happy around 1-2
But if it's a n/a engine it shouldnt require very much spark at all compared to a boosted setup.

But if there are no missfires, there really is nothing to worry about.

Unless running less dwell places less load on the electrical system freeing up electrical power from battery/alternator :P


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