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You're the epitome of "a little knowledge is a dangerous thing."
Man....that is the truth!
I am of the camp that thinks the power is low. My '89 did 240 rw with dual exhaust only, on a dynojet. Adjust that for a Mustang and I'd guess it would be a similar number as the OP got. Stock TB/plenum, runners, base, cam, rockers, manifolds, etc.
Looks like Inj Duty Cycle only got to the high 60s, maybe 70%. I entered 68% into the calc and I used and 26lb injectors and came up with 226 whp. Multiply that by the correction factor 0.98 and you get 221.48. So the dyno seems legit. The graph looks incorrect to me though as the highest Inj Duty Cycle came around 5k rpm and it didn't get into the mid 60s until 4k+. So maybe it is a tach pickup issue or the dyno operator entered some bad info like gear ratio, tire size, weight... etc... and it makes the graph look wonky.
If I had to guess there is quite a bit more left in it with a good tune. Looks lean from your log. It tries to get to the commanded afr but misses the mark to the lean side.
The point is that the problem with the TPI is that the runners are too long and therefore interfere with cylinder filling after about 3000rpm.
We have the same point, however you seem to think that memorizing fancy words without understanding what is really happening is actual knowledge. You've confused memorization with conceptualization.
Your conceptualization is wrong. What you're describing sort of does take place in the collector of an exhaust header. However, what is happening in the intake is contained within each individual runner.
Wave resonance and Helmholtz theories are useful for predicting the impact of intake runner length on engine performance. However, there is very little information in the literature regarding the effects of intake plenum volume. The goal of this study was to determine the effects of intake plenum volume on engine performance for a restricted naturally aspirated engine for Formula SAE (FSAE) vehicle use.
-Due to resonant charging at high RPM, average
pressure in the plenum adjacent to the intake runner
throughout the intake valve open period was seen to
increase as plenum volume was increased and was
directly related to a rise in volumetric efficiency. The
smaller plenums may have negated this charging effect
due to stronger interference waves from neighboring
cylinders
I wonder how important the plenum really is to determining this so called resonance or Helmholtz frequency
Oh ****, the Helmholtz frequency mathematics requires input from the plenum properties...
but lets see the equation maybe it only plays a minor role....
Holy ****! Every single variable of the Helmholtz equation relies on the plenum length area and volume!!
The phenomenon of Helmholtz isn't dependent on a plenum. But that fact does not exclude it from playing a role on engines WITH a plenum.
But you wouldn't know that without doing research on the subject. I mean, it is common knowledge in some places...
the equations for calculating runner length and plenum volume are co-dependant
Yeah uh, I'll keep my conceptualization seems to be working FINE the ol' knoggin **** and I just knew it without looking it up. Imagine knowing something for SURE before you even look it up. How does that happen?
Because I don't memorize jargon and trick myself into thinking I understand. I only always say "I don't fully understand anything. But I try to visualize what I can and keep my mind open to learn more"
The gain in efficiency is due to a pressure pulse that
arrives at the intake valve at or just before the intake valve closure. [Stone, 1999]
Originally Posted by Kingtal0n
In this case the frequency of the engine with the frequency of the sound arrival to the valve. When the sound arrives just as the valve opens the cylinder fill is increased. When the sound bounces from the valve just as it opens the cylinder fill is decreased.
-Due to resonant charging at high RPM, average
pressure in the plenum adjacent to the intake runner
throughout the intake valve open period was seen to
increase as plenum volume was increased and was
directly related to a rise in volumetric efficiency. The
smaller plenums may have negated this charging effect
due to stronger interference waves from neighboring
cylinders
the
compression wave arrives at the intake valve before it
closes, the increased pressure will effectively force more
air into the cylinder [2]. This tuning effect or resonant
supercharging leads to increased volumetric efficiency
and torque. Meanwhile, the expansion waves will travel to the inactive branches (with closed valves) and be reflected as expansion waves back to the active runner
Originally Posted by Kingtal0n
I can clearly see the wave is spreading out into the plenum and interfering with other waves. Therefore the coincidence will be constructive or destructive regarding nearby or recently closed cylinders. The wave which reflects back into the tube is then a combination of influences from other runners who's waves have recently arrived into the plenum.
We have the same point, however you seem to think that memorizing fancy words without understanding what is really happening is actual knowledge. You've confused memorization with conceptualization.
LOL, you mean like the term "water hammer?"
I wonder how important the plenum really is to determining this so called resonance or Helmholtz frequency
Well, at least you now understand that it's a resonance and that Helmholtz laws actually apply. That's progress!
The phenomenon of Helmholtz isn't dependent on a plenum. But that fact does not exclude it from playing a role on engines WITH a plenum.
I never said the plenum doesn't play a role in an engine's performance (where a plenum exists).
Let's try to recap. You originally said:
Around 4200-4400rpm depending on the air temp, water hammer is causing a drop in VE as sound waves created by opposing valves are bouncing from the opening valve just prior to the open event.
I said that is wrong, that the VE drops due to the resonance in the runner tube. I am correct about that. You tried to say that it's pressure waves from the other valves causing it. That is incorrect. It's also not the same thing as the SAE sentence you highlighted:
Originally Posted by SAE
...
Originally Posted by SAE
the expansion waves will travel to the inactive branches (with closed valves) and be reflected as expansion waves back to the active runner.
It's also not the same thing as:
Originally Posted by SAE
The
Originally Posted by SAE
smaller plenums may have negated this charging effect due to stronger interference waves from neighboring cylinders.
Good luck trying to calculate how that affects the individual cylinder VEs in a cross-plane V8, though!
If you want to argue that plenums can influence intake flow in various ways - whether due to waves coming from other cylinders or the same cylinder - I won't argue with you. I'm sure they do, especially as they get smaller. It's not a secret that plenum volume matters. But those things have dick-all to do with why the L98's torque curve falls off a cliff after 3000rpm. The primary problem the TPI intake has is an overly long runner length. Legions of people have tried runners with bigger cross sections or tried to modify the TPI plenum only to find that the thing still has a major resonant restriction above 3000rpm and their engine still can't build real power. You can believe that or not. I don't really give a ****.
In an effort to get this thread back on the rails here...
I realize I was missing a ton of other factors when I mentioned the discrepancy between the WUD datalog of SA and the actual SA tables posted. I am extremely new to the EBL Flash II system and I am actually playing with things now for the first time, in prep for starting up my 85 with it.
If you look in tuner pro, there are 21 different spark advance tables. So even though the main and extended SA tables seem odd, we would also need to know your PE advance tables look like.
There are several different ways to go about tuning SA. For example, you can make your changes in the main and extended tables, zeroing out the PE tables entirely or you can use the PE tables to either add or reduce advance based on MPH, gear or RPM.
I recommend going through all these tables and seeing how they are setup compared to a starting BIN. You shouldn't have any radical changes. I still think your datalogged SA is a little low for a WOT pull, but at least now there is an explaination as to why it is so much lower than your main and extended tables.
I just wanted to update that I'm collecting your inputs and advice. I also consulting BobR the creator of DynamicEFI and have his inputs as well.
attched the base BIN and current BIN. it can be opened by using TunerPro.
YG_100.BIN is the base BIN.
170123 in The current BIN.
EBL_V40.TXT change it to EBL_V40.XDF (tunerpro)
the pdf is the output as PDF for the dyno pull.
I will add, Bob hangs out on thirdgen (as well as others) the tuning section is really good as far as EBL because a lot of guys run it. If you need additional input it would serve well to check that out as well. I believe it was mentioned earlier but figured I'd add it again.
As far as power numbers, I think it comes down to the cam is a little mismatched for the combo but it's not out of line with what a stock L98 would have... the 117 degree LSA is what is hurting it the most as it favors (depending on various things) higher rpm power... They went to a 117 LSA on 88-89 L98s and also went to a 207/213 duration at .050. they then went bac to a 202/207 at 114.5 LSA for whatever reason, which is in line with the 87 cam... Your numbers seem a little low, but not "out of line" but with the advice given you can pick up some numbers for sure. You could always play with the advance of the camshaft too, it would shift the power peak down a little and maybe play nicer with all your parts... Which is easier said than done I know.
I just wanted to update that I'm collecting your inputs and advice. I also consulting BobR the creator of DynamicEFI and have his inputs as well.
attched the base BIN and current BIN. it can be opened by using TunerPro.
YG_100.BIN is the base BIN.
170123 in The current BIN.
EBL_V40.TXT change it to EBL_V40.XDF (tunerpro)
the pdf is the output as PDF for the dyno pull.
What I find most odd is that TPS is not at 100 until almost 4000rpm and MAP is in the low 90s until almost 3800rpm. A pull from a bit lower in RPM might have given a more complete picture.
I looked at some of your SA tables. Things certainly seem high around high map, high rpm portion of the table. The log shows a different story though. Your SA is 35 at peak power and then tapers off from there and there is no knock retard throughout the run.
I've gone through all your tables compared to my bin and the only things I see that would give this result against your main and extended tables would be the PE reduction vs MPH table.
Looking through your previous posts, you have been running EBL for a few years, so you are much more knowledgable than myself at this point. I would just think it would make your life easier to tone down your main and extended SA tables and zero out the PE vs MPH table.
Just to reiterate what others have said, after reviewing your log .pdf, commanded and WB O2 seems a bit too lean, especially above 3900rpm.
I appreciate this thread as it is giving me a chance to explore tunerpro and get familiar with things for my own car. It is amazing how many parameters there are to play with. This is certainly making me feel better going the EBL route versus holley EFI.
Here are two of the BINs I plan to start with. One has the Main and Extended SA tables the same as the included 3006 BIN, the other I modified the tables a bit by adding SA under high RPM, high MAP portions of the table. I may start with the standard SA values until the car has done a few learns, but it seems many agree that the base calibration for SA in the BINs included with the EBL Flash II are very conservative.
Ran a SIM of your engine using the info you provided.
Very conservative model with hot engine, full exhaust.
Laid it on top of your dyno chart.
Something isn't right either with your engine or the dyno?
I know I'm going to sound like a broken record, but does your sim account for the TPI's resonant boost and obstruction? There's no way any engine with a TPI intake is going to run like your sim graph.
What I find most odd is that TPS is not at 100 until almost 4000rpm and MAP is in the low 90s until almost 3800rpm. A pull from a bit lower in RPM might have given a more complete picture.
I looked at some of your SA tables. Things certainly seem high around high map, high rpm portion of the table. The log shows a different story though. Your SA is 35 at peak power and then tapers off from there and there is no knock retard throughout the run.
I've gone through all your tables compared to my bin and the only things I see that would give this result against your main and extended tables would be the PE reduction vs MPH table.
Looking through your previous posts, you have been running EBL for a few years, so you are much more knowledgable than myself at this point. I would just think it would make your life easier to tone down your main and extended SA tables and zero out the PE vs MPH table.
Just to reiterate what others have said, after reviewing your log .pdf, commanded and WB O2 seems a bit too lean, especially above 3900rpm.
I appreciate this thread as it is giving me a chance to explore tunerpro and get familiar with things for my own car. It is amazing how many parameters there are to play with. This is certainly making me feel better going the EBL route versus holley EFI.
Thank you for your response.
Yes, we are a community and we should help each other and share thing even if they are wrong so other can learn from it.
I have noticed the "PE reduction vs MPH table" was too lean (higher AFR). I share with you BobR response to my questions:
Yariv,
> * SA - TCC Locked retard, Should I copy the values from YG_100.BIN > (or zero it from 2600-3200 80-85)?
Probably. The purpose of this table is to prevent chugging and/or detonation when the TCC locks up at lower engine speeds. Note the mid-range of the MAP axis along with the low RPM range.
> * PE - AFR command. I see @ YG_100.BIN is all 12.8. mine is 13.8 up > to 14.1 @ 4000 and above. Should I change mine as in YG_100?
I would. Also, the WB reporting is also on the lean side. Within danger territory.
> * What about SA - main and extended? the area of 4000 up to 6000+ > (extend) is above 40 degrees, isn't it too aggressive? should I reduce
> the area of 4000-6000 RPM @ 95+100 to 33*- 36*?
Give the engine what it wants. For the most part the heads dictate what the SA should be.
I know I'm going to sound like a broken record, but does your sim account for the TPI's resonant boost and obstruction? There's no way any engine with a TPI intake is going to run like your sim graph.
Does 318 flywheel horsepower @ 4600 surprise you for a large tube TPI with his parts combination?
Yariv ... this may not matter but I did not see any atmospheric info on any of your dyno stuff ... you are in Israel ... what were the weather conditions during the dyno test ? ... air temp , barometer , humidity ? I did see an SAE correction factor of 0.98 .
Yariv ... this may not matter but I did not see any atmospheric info on any of your dyno stuff ... you are in Israel ... what were the weather conditions during the dyno test ? ... air temp , barometer , humidity ? I did see an SAE correction factor of 0.98 .
It was about 68F , 50% humid and the Dyno is @ sea level.
Does 318 flywheel horsepower @ 4600 surprise you for a large tube TPI with his parts combination?
Yes. If that combo had an intake that didn't sharply impede airflow around 4000rpm, then I could see the torque and power curves you posted. But with a TPI intake - regardless of larger runner cross sections - the torque curve won't extend as flat and remain as high above 3000rpm as your graph portrays. It's not about steady-state flow like you find on a flow bench, but rather about the resonant tuning we were trying to discuss above. The TPI runner length is just tuned to such a low RPM that it impedes airflow in the RPM range where you need to run to build real power. Bigger runner cross sections, porting the base, and modifying the plenum can't make that much of a difference.
If the only thing the OP did was swap on a short-runner intake of some sort, he'd unlock that power. As someone else already suggested, the very wide LSA of 117 means there is almost no overlap on that cam, which pushes the power band higher (or tries to). However, the intake is blocking flow up there, so it's kind of wasted. Swapping it out for one that flows well up to 5500-6000rpm would be the easy-button solution to get the kind of curves you showed.
If someone insists on sticking with a TPI intake, then I think the thing to do is focus on building power in the midrange. That calls for a whole lot more overlap. You don't need tons of lift (a little less than .500" would be plenty) and you don't want lots of duration (205-210 at 0.050 is probably plenty). I'd find the cam lobes with aggressive ramp rates and 1.6 rockers so the valves get open early and I'd spec it on an LSA of 106-108. Also, I'd want to find heads with relatively small runner volumes but high port velocities. The heads the OP has seem pretty "lazy" based on the published flow numbers and 195cc port volume. Contrast those with, for example, the AFR 180 street casting: it has 15cc less port volume but still flows 8cfm more at 0.500 lift and more importantly it flows 17cfm more at 0.400 lift where the OP's cam is living. A cam and heads like that would have a really strong midrange: the car would be significantly faster through the gears (probably shifting around 5000-5500rpm) with better average power and it would feel a whole lot faster.
PS - None of this negates the import discussion of tuning that is taking place. Also, I have no idea how the OP's location of Israel impacts parts availability and regulations.
Yes. If that combo had an intake that didn't sharply impede airflow around 4000rpm, then I could see the torque and power curves you posted. But with a TPI intake - regardless of larger runner cross sections - the torque curve won't extend as flat and remain as high above 3000rpm as your graph portrays. It's not about steady-state flow like you find on a flow bench, but rather about the resonant tuning we were trying to discuss above. The TPI runner length is just tuned to such a low RPM that it impedes airflow in the RPM range where you need to run to build real power. Bigger runner cross sections, porting the base, and modifying the plenum can't make that much of a difference.
If the only thing the OP did was swap on a short-runner intake of some sort, he'd unlock that power. As someone else already suggested, the very wide LSA of 117 means there is almost no overlap on that cam, which pushes the power band higher (or tries to). However, the intake is blocking flow up there, so it's kind of wasted. Swapping it out for one that flows well up to 5500-6000rpm would be the easy-button solution to get the kind of curves you showed.
If someone insists on sticking with a TPI intake, then I think the thing to do is focus on building power in the midrange. That calls for a whole lot more overlap. You don't need tons of lift (a little less than .500" would be plenty) and you don't want lots of duration (205-210 at 0.050 is probably plenty). I'd find the cam lobes with aggressive ramp rates and 1.6 rockers so the valves get open early and I'd spec it on an LSA of 106-108. Also, I'd want to find heads with relatively small runner volumes but high port velocities. The heads the OP has seem pretty "lazy" based on the published flow numbers and 195cc port volume. Contrast those with, for example, the AFR 180 street casting: it has 15cc less port volume but still flows 8cfm more at 0.500 lift and more importantly it flows 17cfm more at 0.400 lift where the OP's cam is living. A cam and heads like that would have a really strong midrange: the car would be significantly faster through the gears (probably shifting around 5000-5500rpm) with better average power and it would feel a whole lot faster.
PS - None of this negates the import discussion of tuning that is taking place. Also, I have no idea how the OP's location of Israel impacts parts availability and regulations.
From a lot of the tests I've seen over the years, regardless of setup, a SBC seems to favor near 108 LSA for the best mid peak and average torque... I know people have mixed feelings on Vizards 128 rule... but you start looking at all the data from all those tests people do on LSA and it does come pretty close... not really arguing just saying for max effort the 108 would be a nice fit but also be a lot more annoying to tune for drivability.
One other interesting thing about the 117 LSA cam GM did use in the L98 was it had a lot more duration. So even though the LSA was pushed wider, with that extra duration you can assume it also had more overlap between intake and exhaust which probably offset some of the pushing up of the LSA. Just food for thought. I do think there is power on the table still. I haven't been able to look at the data log, my laptop has been down, but I feel with the direction given there can be reasonable gains had for sure.
PS - None of this negates the import discussion of tuning that is taking place. Also, I have no idea how the OP's location of Israel impacts parts availability and regulations.
Its very expemsive to buy parts for the Vette. For instance pair of heads that costs about 1000$ (exclude tax) in the end it costs me about 1800$ (local taxes and shipping). If I remember, the BP heads cost me in 07/2020 about 900$ before taxes and shipping.
