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mister t
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« Reply #15 on: March 10, 2018, 11:53:16 AM »

So if I understand you correctly, you're of the opinion that your dyno is a better measure of a car's power output specifically because it DOESN'T replicate the temperatures and airflow that a car encounters in normal operation???

You ARE also aware that the same confounds which you reference (i.e. different ambient temps, etc...) are still present on your dyno. Further, issues like heatsoak are probably exacerbated on your dyno vis a vis a moving car on the highway.

When I look at the content of your reply, you really haven't addressed why Virtual Dyno isn't reliable. Nor have you addressed the dyno vs virtual dyno testing I sent you in that link above.

While it may seem that I'm nitpicking, I am only doing so because I expect well thought out / logical responses from members on this forum (especially senior ones).

Dodging valid questions and stating opinion evidence as a fait accompli is what I expect out of Audizine forum members. Maybe I'm mistaken, however I think that we're better than that here.

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mister t
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« Reply #16 on: March 10, 2018, 12:13:23 PM »

SMH

Sorry, that motor is a POS

Sorry, still gonna disagree with you Nyet.

While they may have their issues (re: cam adjusters and rails) the BBK 4.2 with it's variable independent inlet cam phasing, dual length intake manifold,  11:1 compression, lightweight valvetrain and sheer size (relative to other Audi offerings) make it an incredibly responsive and torquey engine which will still happily rev to 7200 RPM and sound knee droppingly gorgeous while it does it.

In fact, I have yet to see another crossplane V8 of this size which is more rev-happy as this engine.

As indicated in my earlier posts, my 2004 S4 has absolutely every modification you can make without going internal and (corrected for elevation) it's putting out between 380-400 CHP which puts it just about perfectly at that 1/10 HP/Lb ratio which I find to be ideal (fast enough to be fun, but not overpowering the chassis and/or tempting you to loose your licence).

Another often ignored concept which was made known to me by one of the owners of Cone Engineering (one of California's best exhaust system manufacturers) is the concept of 'time until torque'.

As it's name suggests, it refers to the delay from the time you put your foot down, to the time when the engine delivers your torque request. In may cases, it may only be 0.1 0.2 seconds difference N/A vs Turbo, but in the real world, where we all drive in cut and thrust traffic, ANY delay will be felt as a detriment by a decent driver.

What I can say, is that in the era of downsized engines we are living in, I'll probably never have another car that responds as quickly as my 4.2 S4. With a lightweight flywheel, throttle response and torque is INSTANT!!! If I so much as breathe on the throttle, the car just snaps to it.

Don't get me wrong, having done 7 different turbo set-ups on my Passat 1.8T and A4 1.8T ranging from a stock K03 to a fire-breathing Comp 5556, I have plenty of love for turbo cars and totally agree that for ultimate power, F/I is the way to go.

However, if I was asked to pick one Audi engine to live with for the rest of my life in daily driving, I would give SERIOUS consideration to a well modified and sorted 4.2 V8.
« Last Edit: March 10, 2018, 12:24:18 PM by mister t » Logged
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« Reply #17 on: March 10, 2018, 12:30:08 PM »

There are gains to be made over stock programming on the 4.2 fsi engines.
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« Reply #18 on: March 10, 2018, 01:29:10 PM »

You ARE also aware that the same confounds which you reference (i.e. different ambient temps, etc...) are still present on your dyno. Further, issues like heatsoak are probably exacerbated on your dyno vis a vis a moving car on the highway.

Precisely that, especially when one uses a tiny desk fan for cooling. I am a dyno believer myself (especially proper direct axle steady state one like Dynapack), but I am not dismissing reasonable field methods.
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nyet
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« Reply #19 on: March 10, 2018, 01:42:45 PM »

It's a fine motor stock. For tuning purposes, it's a POS
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mister t
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« Reply #20 on: March 10, 2018, 02:32:30 PM »

It's a fine motor stock. For tuning purposes, it's a POS

Actually Nyet, while I can totally see why you might have that impression (due to so many incompetent tuners and vendors selling crap for these engines) these motors respond well to PROPER tuning (BIIIIGGG emphasis on the proper part).

Having tuned and owned 2 of them (2004 S4 sedan and a 2005 S4 cabrio) I found that when you uncork them, they're a gem of an engine.

I think where a lot of the misconceptions stem from is the fact that VERY few people know how to:

1) fabricate the proper hardware (i.e. headers, collectors, exhaust, intake manifold, etc...)

2) tune the ECU once the hardware is bolted on

With respect to tuning it, I've literally spent in the thousands of cumulative hours and hundreds of file revisions. I don't exaggerate when I say that I've looked at over a gigabyte worth of logging data, trying to work out the optimal cam phasing and manifold changeover points whenever I made significant VE changes to the car.

Since I'm not on Audizine, I can finally let go and rip on JHM lololol. Having looked at their almighty tune (courtesy of Daz (God rest his soul)) I was amazed that JHM did NOTHING to change the cam phasing!!!!

Why this is, I'll never know, because whenever I challenge them about it on the 'zine, JHM suddenly goes very very quiet.... But what I can tell you from having tuned these engines 1) stock, 2) catless downpipes and 3) w headers is that the optimal cam phasing is VERY VERY VERY different for all three.

For example, with catless downpipes, as I indicated earlier, you need to keep the lobe angles separated much farther into the RPM band than you do with the cats on.

However, with headers, you can introduce overlap much earlier. That said, I found that in order to keep the airflow from flatlining, i had to introduce another 'pump' (i.e. quick retard over 150 RPM) and then quickly drop back into overlap for that last 1000 RPM.

Interestingly enough, you can actually feel it in some gears, almost like the engine takes another gulp of air and shoots towards 7200 RPM.

To make an analogy of it, think of it like body surfing. When you start dropping into overlap, the air pulses become excited as the engine starts scavenging and you get a sudden surge in torque.

However, since your range of cam phasing is limited, you eventually loose momentum and the airflow starts stalling out.

That's when I pull the cam timing back, usually to coincide with an event like the manifold runner changeover. When you do that, it's like going down to the bottom of where you're standing and pushing off into another wave.

Any of that make sense?

In any event, due to the comparative rarity of these engines, there is NO information online about how to tune them. Everything I've learned has been gleaned from other platforms and many, many many scientific journal articles on pulse dynamics and resonance theory.

So while I can certainly see how you may have gotten the impression that these engines were duds in terms of tuning, they actually respond very well IF you know what you're doing; and trust me, that's a BIIIGGGG if...
« Last Edit: March 10, 2018, 02:41:42 PM by mister t » Logged
mister t
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« Reply #21 on: March 10, 2018, 02:38:14 PM »

There are gains to be made over stock programming on the 4.2 fsi engines.

Agreed, same goes for the port injected 4.2 V8.

Ignition timing plays a huge part in the 5 valve engines making power.

After a lot of head scratching, I came to the conclusion that these engines need a lot of timing due to the 3rd intake valve shrouding the sparkplug.

Basically, in order for the flame front to ignite optimally, you need a lot of advance compared to a 4 valve configuration.

Question, have you played around much with the cam timing on the 4.2 FSI? In particular, on engines with the cats removed and a proper X pipe exhaust?
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nyet
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« Reply #22 on: March 10, 2018, 02:40:14 PM »

Makes sense. I understand what you are are saying about being uncommon, and that being the reason the 4.2 seems to not respond well to tuning.

Also, remember i'm accustomed to tuning solely FI motors. Tuning NA motors just doesn't feel that gratifying because of the outrageous cost/benefit.

that said, the non-rs4 4.2 is definitely a dog.
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ME7.1 tuning guide
ECUx Plot
ME7Sum checksum
Trim heatmap tool

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
mister t
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« Reply #23 on: March 10, 2018, 02:45:49 PM »

Makes sense. I understand what you are are saying about being uncommon, and that being the reason the 4.2 seems to not respond well to tuning.

Also, remember i'm accustomed to tuning solely FI motors. Tuning NA motors just doesn't feel that gratifying because of the outrageous cost/benefit.

that said, the non-rs4 4.2 is definitely a dog.

Ohhhh, trust me man, I totally agree with you that tuning these engines to go fast can be an excruciatingly long process lol Wink

That said, I find it kind of rewarding, especially since so few people have really taken the time to figure out how to go about it properly.

Finally, as for the non RS4 4.2 FSI, well I've never tuned or owned one, so yeah, let's both agree it's the dog of the bunch hahaha.
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mister t
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« Reply #24 on: March 10, 2018, 02:55:53 PM »

On a bit of a different note, I would REALLY like to see what kind of gains you could make on a 4.2 with a set of upgraded cams.

I know Schrick sells some, but they're ungodly expensive and I have yet to see ANY information other than one thread on Audizine where the guy just kinda mumbled some dyno number (without a graph) and said that he wasn't very impressed.

Again though, I'll bet that IF the tune was dialed in right, he would have noticed some substantial gains.

When I look at the Schrick specs, it appears that they pretty much used the grind from their VR6 cams and just ported it onto the V8 cams. This would make sense given the relatively low rate of return they would be getting from a 4.2 camshaft.

With all that said, the Shrick VR6 cams seem to make some solid gains on an R32 (15 WHP or so IIRC).

If you were to extrapolate that to a 4.2 v8, I would think that a set of upgraded cams could let you crack 420-430 CHP if everything else was done correctly.

(PS: in my experience, the stock cams seem to choke out at about 380-400 CHP in terms of absolute output).

Any N/A tuning experts care to weigh in here?
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prj
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« Reply #25 on: March 10, 2018, 05:06:11 PM »

Dodging valid questions and stating opinion evidence as a fait accompli is what I expect out of Audizine forum members. Maybe I'm mistaken, however I think that we're better than that here.

Yo dude.
Call back when you have actually tuned of these on a real dyno. Until then, no amount of typing walls of text will make anything you say true.
Simply, you have no evidence to back up your claims, end of story.

You ARE also aware that the same confounds which you reference (i.e. different ambient temps, etc...) are still present on your dyno. Further, issues like heatsoak are probably exacerbated on your dyno vis a vis a moving car on the highway.
Actually they are not present. My dyno's cooling is better than you driving on the highway. By far.
Unless you're doing 200+ km/h.
You know how they say assumption is the mother of all fuckups? I can pull a 1000 hp car back to back in my dyno cell and the ambient temp never goes up, because the whole volume of air in the dyno cell is fully changed every 8 seconds.

Precisely that, especially when one uses a tiny desk fan for cooling. I am a dyno believer myself (especially proper direct axle steady state one like Dynapack), but I am not dismissing reasonable field methods.
My 15kw dual centri blower setup would like to have a word with you.
My cooling blowers make more power than the anecdotal "power gains" discussed in this thread LOL.
« Last Edit: March 10, 2018, 05:08:32 PM by prj » Logged

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mister t
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« Reply #26 on: March 10, 2018, 07:11:05 PM »

Yo dude.
Call back when you have actually tuned of these on a real dyno. Until then, no amount of typing walls of text will make anything you say true.
Simply, you have no evidence to back up your claims, end of story.
Actually they are not present. My dyno's cooling is better than you driving on the highway. By far.
Unless you're doing 200+ km/h.
You know how they say assumption is the mother of all fuckups? I can pull a 1000 hp car back to back in my dyno cell and the ambient temp never goes up, because the whole volume of air in the dyno cell is fully changed every 8 seconds.
My 15kw dual centri blower setup would like to have a word with you.
My cooling blowers make more power than the anecdotal "power gains" discussed in this thread LOL.

Dude, I'm not questioning your knowledge as a whole. So calm down, take a breath and drop the chest pounding. I see enough of these responses on VWVortex and Audizine and it certainly doesn't help further your argument.

Look, I don't beat around the bush. So I'll say flat out, I've read your posts. You're very good at what you do. We all know that.

However, NONE of us knows it all and that includes you (and me for that matter).

Assuming the previous statement is true, then that means none of our statements here are above question and that includes you

I'm a smart guy, smarter than 99% of the rest of the population according to my IQ test scores (and the 3.93 GPA over the last 2 years of my undergrad) and the convocation ceremony for my Juris Doctor Degree (after 7 years of post secondary) which was held along with Medical Doctors and Veterinarians.

NOTE**I don't add that last part to be a pretentious dick. I only include it to establish that I use my head for something other than a hat rack.  

Further, these smarts I refer to also apply to anything else I take an interest in, such as all things automotive. You should also know that It's more than a hobby to me. Ask anyone one who knows me and they'll tell you and it's all I eat sleep and breathe.

So, now that we've pulled our respective dicks out and measured them. I'm going to suggest that since NEITHER of us knows it all, perhaps it would serve our respective interests if we showed each other some mutual respect. I'm certainly open to if you are.

However, if you choose otherwise, while I certainly won't go out of my way to antagonize you, be advised that I'm also not going to pull any punches or questions. Nor will I back down if confronted.

In any event, I leave the ball in your court. I think we both make better allies than enemies. What do you think?
« Last Edit: March 10, 2018, 07:33:38 PM by mister t » Logged
prj
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« Reply #27 on: March 10, 2018, 07:15:41 PM »

It's simple.
Nothing you do on a stock car will amount to anything, which is of statistical importance.
I can't be arsed to argue about virtual dyno, it's a waste of time. Anyone who is remotely serious about this knows that runs on the road are not repeatable.
Even on the dyno every run will have somewhat different whp, but the coastdown measurement fixes that issue.

Advance the timing, you hit knock -> you lose power due to timing pull.
Change the camshaft adjustment -> you lose power unless the car has stretched chains, which means it needs repair.
Adjust the fueling -> gain absolutely nothing because they already run best power.
Try tuning one on standalone in a race car -> you have a hell of a time getting it to run as well as on the stock ecm.

If you want to make power, slap a nitrous kit on or turbo/supercharge it. Probably a waste of time at this point though.

There are very few OEM NA engines where you can make actual power gains that amount to more than insignificant variance.
« Last Edit: March 10, 2018, 07:19:01 PM by prj » Logged

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mister t
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« Reply #28 on: March 10, 2018, 07:23:01 PM »

Cool, I take that as a yes (in your own way Wink

Thank you for providing a constructive response.
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mister t
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« Reply #29 on: March 11, 2018, 11:25:27 AM »

The other aspect that we haven't discussed about tuning a stock 4.2 is transient response.

Throttle mapping, fuel enrichment delays, ignition timing at part throttle, etc... are all ways to enhance a stock 4.2 V8 file.

The guys at Cone Engineering turned me on to the concept of 'time to torque' and I firmly believe that it's an important measure of how well an engine performs.

Problem is, all those transient responses don't show on a dyno.

However, on a heavy pig like a Touareg, VW/Audi the stock tuning is heavily biased towards fuel economy and numb/fuzzy throttle response. While this may only mean a couple tenths of a second delay, when you're driving in heavy cut and thrust traffic, those tenths of a second often translate into whether you can execute a quick move or not.

Ergo, I maintain that tuning these cars is useful, regardless of whether or not it makes a difference to the absolute WOT power output.

PS: I should add that I've had a number of people drive the stock Touareg that I tuned and 100% of them have agreed that there is a noticeable improvement to how the vehicle performs. As they say, 60 million Elvis fans can't be wrong Wink
« Last Edit: March 11, 2018, 11:39:47 AM by mister t » Logged
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