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Author Topic: Audi RS4  (Read 21375 times)
mikers4
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« on: February 18, 2018, 10:21:53 AM »

Hi, I am trying to read an Audi RS4 2007 B7 with MPPS v16 but it won’t find the master or slave ECU...?

It won’t even show the ECU info.... I know it has a map on it but thought it would still show the ECU ID?

I have removed fuse 15 for cluster in case this has any effect but it has not done anything.

Any help appreciated.

Mike
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nyet
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« Reply #1 on: February 18, 2018, 04:06:52 PM »

Why bother? You can't get any more power out of that motor. Waste of time; its crap.
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prj
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« Reply #2 on: February 18, 2018, 06:52:38 PM »

This is not quite true. There is a torque limiter in the first few gears that limits the throttle angle between 60-70%.
Lifting this limiter makes a noticeable difference around town.
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mikers4
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« Reply #3 on: February 18, 2018, 11:29:22 PM »

I wanted to look at improving low rpm throttle input as it is very jerky when cold. Only been like that since map installed.

Also wanted to lower the cold rpm limiter down from 7k to 5k but can’t even read th ECU.

As for not getting any power it is already 430bhp (carbon clean and intake flap delete)

Thanks for the input.

Mike
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mister t
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« Reply #4 on: February 22, 2018, 11:49:22 AM »

Why bother? You can't get any more power out of that motor. Waste of time; its crap.

Totally disagree, there are some significant gains to be made tuning any of the N/A Audi engines. I've personally tuned 2 BBK 4.2 V8's my 3.0 AVK and my folk's AXQ 4.2 V8. In all instances, overall performance was increased as well as transitory responses.

In the case of the touareg,  the tune I wrote made a significant difference despite it being completely stock. Even my parents think it's a marked improvement.

In the case of a modified N/A engine (especially one with the cats removed), dialing in the cam phasing is critical if you want to get the most out of the engine. Adding in timing as well as enriching the A/F ratios will also make more power especially under the curve. Finally, dropping the time it takes to go into closed loop makes a significant difference to transitory responses. 

So while you certainly won't see the gains you'd see in the case of a turbocharged car, it's certainly worth remapping an N/A car
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prj
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« Reply #5 on: February 22, 2018, 04:13:44 PM »

Please show some dyno graphs to back up your claims.

Most VAG V8 engines run lambda 0.9 flat until temperature limit at WOT through lamfa.
Adding more fuel does absolutely nothing to power. Timing has been MBT on 98 RON for me.
Camshaft timing has been on point apart from a couple very specific engines.

Let me guess, you never dynoed before and after. I have on my dyno.
Waste of time.
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mister t
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« Reply #6 on: March 09, 2018, 05:07:26 PM »

Here is a recent example of where dialing in the cam timing resulted in another peak 12 AWHP and a noticeable gain between 6000-7000 RPM on my recent S4 build.

MODS:

-Headers
-dual X pipe
-shaved throttle plate
-re-engineered intake manifold
-3 inch smooth bore intake tube
-My own ECU tune

DOUBLE VS TRIPLE PUMP CAM TIMING DYNO by zimbu themonkey, on Flickr

DOUBLE VS TRIPLE PUMP CAM TIMING DYNO POST 6200 ZOOM by zimbu themonkey, on Flickr

Triple pump cam timing (best cam timing)
triple pump cam timing by zimbu themonkey, on Flickr

Double pump cam timing (drops off from 6000-7000 RPM)
double pump cam timing by zimbu themonkey, on Flickr



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mister t
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« Reply #7 on: March 09, 2018, 05:14:57 PM »

As well, here are pictures of my data logs of how my B6 S4 Cabrio lost a ton of power when I went to 2.5 in straight pipes on the stock cam phasing and manifold changeover.

STOCK VS CATLESS DOWNPIPES VS NEW VS OLD CAM PHASING MAF READINGS by zimbu themonkey, on Flickr
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contrast
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« Reply #8 on: March 09, 2018, 05:27:38 PM »

I don’t think Virtual Dyno will cut it...
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prj
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« Reply #9 on: March 09, 2018, 06:21:30 PM »

lol virtual dyno.
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nyet
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« Reply #10 on: March 09, 2018, 09:39:18 PM »

SMH

Sorry, that motor is a POS
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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 #11 on: March 09, 2018, 10:15:54 PM »

lol virtual dyno.

Well, if it's good enough for the guys at MotoIQ, it's good enough for me.

Please tell me exactly how it's a deficient metric? Assuming that the pulls are done in 3rd gear, same day, same stretch of road, how is it NOT accurate?

I'm not using it for a measure of outright power, however when two pulls overlap so closely with a smoothing factor of 1 and my MAF readings jump in exactly the same spot between 6000-7000 RPM, please explain how there WASN'T a gain in HP.

prj, you wanted evidence that tuning these motors is worthwhile, I took the time to provide you with that evidence, the least you can do is address my point.

(Seriously, this place is starting to sound like the B6/B7 S4 forum on Audizine...)
« Last Edit: March 09, 2018, 10:53:51 PM by mister t » Logged
mister t
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« Reply #12 on: March 10, 2018, 12:17:54 AM »

Finally, here's an interesting thread showing multiple comparisons between Virtual Dyno results and actual Dyno results.

https://innovativetuning.wordpress.com/our-experiments-with-virtual-dyno/

If you take the time to read through it, you will find that the results are in fact, eerily close.

Note, that this is above the scope of my argument for Virtual Dyno being an accurate metric for pre-post changes. However, it's simply additional evidence which suggests (as I've been saying all along) that Virtual Dyno IS in fact accurate and therefore the 12 AWHP peak gain that I demonstrated between 6000-7000 RPM on my S4 is legitimate.

Finally, prj, if you could be so kind, I would honestly like to get your input as to why that 3rd rise and fall of the cam timing had such an effect on the engine vs just continuing to overlap the valve angles as the RPM's rose. (I have my own theory, but I'd certainly appreciate some extra input from another who is well versed on the subject).
« Last Edit: March 10, 2018, 12:19:39 AM by mister t » Logged
mister t
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« Reply #13 on: March 10, 2018, 12:27:59 AM »

Finally, I wish to point out that no one here addressed the post where I found that I was loosing major power with catless downpipes and the stock cam timing.

My conclusion was that this phenomenon was due to the internal construction of the S4 exhaust manifolds.

Basically, the fact that you had these tiny tubes keeping the pulses separated in that cloverleaf arrangement until they hit the end of the manifold, means that the exhaust gas is in a very high pressure area. Then, when it hits the end of the manifold and there's no longer any cat to slow the pulses down, they exit into a massive vacuum.

This causes a reversion as they exit, which likely pushes some of the exhaust pulse back into the chamber and out into the intake manifold during overlap before the exhaust valve even has a chance to close.
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prj
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« Reply #14 on: March 10, 2018, 08:30:49 AM »

1. If you think "virtual dyno" is evidence, then LOL. I can't even be arsed to explain. I have my own 4x4 non-virtual-real-world dyno and I trust that any day over someone doing pulls on the road with different drivetrain temperatures, different wind, different outside temperatures and so on.
2. The car was not stock.
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