LINK Standalone.
02-12-2008, 09:34 AM
#121
Drifting
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But why do you have a problem with that? Why do you say it would not need bigger injectors?
I can understand the point Eniac made... that HP @ RPM is dealt with by the TQ to HP conversion equation... BUT this assumes BSFC would remain constant, which I cannot see as being the case. From memory, it was this assumption about BSFC that A.Wayne was critical of... I think he mentioned in certain applications it really needs to be determined on the dyno... otherwise it's really just a lucky guess.
I would expect BSFC to increase as you go from 6,000 to 9,000 rpm and hence I can see A.Wayne's point.
Not sure I quite follow Chris White's logic where he said:
"So if you choose the correct injector for the 6k rpm engine it will be too small for the 9k engine – by a lot! (for the sake of the argument we will assume that all other things – fuel pressure and boost – remain the same). At 9k RPM you only have 2/3rds of the ‘real time’ to inject the same amount of fuel that you would have at 6k RPM."
As, assuming the same BSFC, which he seems to be, yes, you'd only have 2/3 the real time but you'd also only need 2/3 the fuel per cycle... the net result would be identical fuel consumption (I'm not suggesting this would in fact be the case, because i content that BSFC would in fact increase).
The thing to remember here is that A.Wayne mentioned 500 HP @ 6,000 and 9,000 rpm... not 500 TQ. What Chris White said would make sense to me if we were talking about TQ at the same level for 6,000 and 9,000 rpm with BSFC remaining constant. But 500 HP @ 9,000 rpm is a lot less TQ @ 9,000 rpm than 500 HP @ 6,000 rpm is TQ @ 6,000 rpm.
Perhaps, A.Wayne will e good enough to step in and further explain what he meant... I'm asking nicely!
I can understand the point Eniac made... that HP @ RPM is dealt with by the TQ to HP conversion equation... BUT this assumes BSFC would remain constant, which I cannot see as being the case. From memory, it was this assumption about BSFC that A.Wayne was critical of... I think he mentioned in certain applications it really needs to be determined on the dyno... otherwise it's really just a lucky guess.
I would expect BSFC to increase as you go from 6,000 to 9,000 rpm and hence I can see A.Wayne's point.
Not sure I quite follow Chris White's logic where he said:
"So if you choose the correct injector for the 6k rpm engine it will be too small for the 9k engine – by a lot! (for the sake of the argument we will assume that all other things – fuel pressure and boost – remain the same). At 9k RPM you only have 2/3rds of the ‘real time’ to inject the same amount of fuel that you would have at 6k RPM."
As, assuming the same BSFC, which he seems to be, yes, you'd only have 2/3 the real time but you'd also only need 2/3 the fuel per cycle... the net result would be identical fuel consumption (I'm not suggesting this would in fact be the case, because i content that BSFC would in fact increase).
The thing to remember here is that A.Wayne mentioned 500 HP @ 6,000 and 9,000 rpm... not 500 TQ. What Chris White said would make sense to me if we were talking about TQ at the same level for 6,000 and 9,000 rpm with BSFC remaining constant. But 500 HP @ 9,000 rpm is a lot less TQ @ 9,000 rpm than 500 HP @ 6,000 rpm is TQ @ 6,000 rpm.
Perhaps, A.Wayne will e good enough to step in and further explain what he meant... I'm asking nicely!
I know that formula is not exact, but nothing is exact on paper due to real world variables.
02-12-2008, 10:03 AM
#123
On the subject of VE, it seems like this is why a Stand Alone with a VE table is absolutely necessary. For each setup it would be different. Engine conditions will also make it different. Even air filter choices affect VE at different RPMS that VE would have to be corrected for. I went with a stand alone make adjustments to keep up with mods.
02-12-2008, 04:35 PM
#124
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So do you need to determine your VE before hitting the dyno?
02-13-2008, 02:32 AM
#125
Burning Brakes
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Not really unless of course you are planning to fire it up and then immediatley go to high boost without doing any detailed tuning. If you plan to get a decent base fuel and ign map and then either go to a dyno or with datalogging of afrs, Egts and possibly knock sensing, you can figure out what your engine needs in the different operating conditions. Then get to a dyno with the help of some good tuners and fine tune for max power that you are looking for.
02-13-2008, 03:01 AM
#127
Burning Brakes
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02-13-2008, 03:19 AM
#128
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Andrew, what do you think of the thought that I don't need the Knockblock as a permanent fixture, rather a tuning tool? Doesn't the LINK have a built in knockblock or sensor?
02-13-2008, 04:23 AM
#129
Drifting
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i don't think it does have it built in . i think you may be able to retain the KLR for knock monitoring . the old amp and head phones is the best from all accounts and cheap as **** . its often not possible to log Knock sensing on the dyno but it's crazy to try tune much with out any knock monitoring
02-13-2008, 06:20 AM
#130
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Thread Starter
The tuner has all the knock monitoring equip and I'm not going crazy trying to squeeze every last morsel out of this build. So should be ok, but I'll get the KB if it's deemed the best form of insurance.
02-13-2008, 08:07 AM
#131
If you are using a standalone that has knock sensor control then definitely use it. Better safe than sorry. I know the tec3r does support knock sensors and also it is possible (how mine is set up) to still use the two factory knock sensors.
VE is set up in some standalones initially at 100% enrichment. Meaning that we assume VE is a straight line rising as rpm goes up. Thing is at certain rpm points the engine may make better use of the air moving through it than other times so say at 4600 rpm AFR's go rich for a 500 rpm range. VE for that RPM point can be decreased say 10% (so take off 10% of whatever the amount of fuel for this point is) if lean then 10% more fuel (or any percentage increment you want to start with). Then run through the same range and see if AFR stays where you want it. Not easy to tune because it is difficult, usually mistakes are made because we are in such a hurry to burn up the road and drive that we sometimes skip the important little things that make the difference.
Also, do not forget to choose the correct combustion chamber design for your application. Notice how the 3.0L 16V and the 8v 3.0 L have different combustion chamber designs. SO choosing the wrong pistons could cause the traveling flame front to exert its hammer like force of the center line of the piston/rod. Like pushing a car straight from the far right corner. Lines of force can make critical differences as some have already found out.
VE is set up in some standalones initially at 100% enrichment. Meaning that we assume VE is a straight line rising as rpm goes up. Thing is at certain rpm points the engine may make better use of the air moving through it than other times so say at 4600 rpm AFR's go rich for a 500 rpm range. VE for that RPM point can be decreased say 10% (so take off 10% of whatever the amount of fuel for this point is) if lean then 10% more fuel (or any percentage increment you want to start with). Then run through the same range and see if AFR stays where you want it. Not easy to tune because it is difficult, usually mistakes are made because we are in such a hurry to burn up the road and drive that we sometimes skip the important little things that make the difference.
Also, do not forget to choose the correct combustion chamber design for your application. Notice how the 3.0L 16V and the 8v 3.0 L have different combustion chamber designs. SO choosing the wrong pistons could cause the traveling flame front to exert its hammer like force of the center line of the piston/rod. Like pushing a car straight from the far right corner. Lines of force can make critical differences as some have already found out.
