Lost the kick at 5000 rpm

[silverRS4]

time ~10 sec
mixture is perfect
timing is perfect

my bet, flaps

Intake air temp is high. A 10-second time is normal with a method that doesn't depend on eyeballs and finger tips. My bet, the car is fine and times will drop substantially with cooler temps.

[ArthurPE]

agree 100%
air density
that is why it is measured in mass flow, not volumetric flow
there is no 'right' number, it varies with temp, atm pressure, altitude, etc.

A car with a new engine will flow 165g/s per bank.

Not when the IAT is 36C. You need to be more careful with your comments or RS4 people will start looking for airflow problems where there are none, i.e. "Why can I only get 150 g/s?, what's wrong with my car?" If you determined the volumetric efficiency of an RS4 that's pulling in 150 g/s per bank at 36C, you'd see it's in line with a healthy RS4.

[ArthurPE]

I'm not sure
it's not that much higher than Mals (36 vs 30 or so)
and yet Mals car, depite being 200+ lbs heavier, ran 1.7 sec faster
Mal's g/sec is a bit higher over the range

I'd like to see him run it again with high resolution

time ~10 sec
mixture is perfect
timing is perfect

my bet, flaps

Intake air temp is high. A 10-second time is normal with a method that doesn't depend on eyeballs and finger tips. My bet, the car is fine and times will drop substantially with cooler temps.

[neckarsulm]

ArthurPE wrote;

"time ~10 sec
mixture is perfect
timing is perfect

my bet, flaps"

Are you suggesting their is an issue with my flaps and if so is it the airbox one or intake manifold flaps?

FYI this data was taken just after the car had just driven within the speed limit on a slow urban road, the DIS run was done when the car had been driving along flowing A/B roads

Thanks for all the analysis chaps

[ArthurPE]

Forget the AFR's, get a GTR - sorted

simism
very useful

[Doug_S2]

that is at similar intake temperatures with ambient of 17/18 outside.: new engine 1000miles old after running it in, 405ps on our dyno - the only stock uncleaned car that has dynoed over 400 on our dyno.

[ArthurPE]

honestly, without a few more runs at high resolution it's too early to say
everything seems fine, but the times do seem a bit slow...

ArthurPE wrote;

"time ~10 sec
mixture is perfect
timing is perfect

my bet, flaps"

Are you suggesting their is an issue with my flaps and if so is it the airbox one or intake manifold flaps?

FYI this data was taken just after the car had just driven within the speed limit on a slow urban road, the DIS run was done when the car had been driving along flowing A/B roads

Thanks for all the analysis chaps

[ArthurPE]

Let the kids win.

simism

do you think post count ~ credibility?
it's not working

[ArthurPE]

am I the only one who noticed sims NEVER gets involved in technical discussions?
no comments on timing, mixture as relates to deposits, ie, no impact, although he contends that it does...

only divisive, political, gibberish, to cause trouble...to inflame...
BS like the problem is 'German engineering' when the shocks are built by the Japanese...
or the attacks against Petrol Dave or P_G becasue we share an opinion on ocassion, and do not on others
you guys hanging your hat with his are seriously misguided or mislead...
I do not want a 'following', as it appears the 'messiah' is attempting to generate...

do not let him distract from the technical discussion
even if you don't agree with me (<1% vs >25% for dcr, deposit impact, HP rating, etc.) it's technical, not personal and vindictive like him....
after all, one sided technical discussions seldom bear fruit...

[neckarsulm]

am I the only one who noticed sims NEVER gets involved in technical discussions?
no comments on timing, mixture as relates to deposits, ie, no impact, although he contends that it does...

just ignore trolls, both your posts and Dougs are far more useful to owners.

[silverRS4]

that is at similar intake temperatures with ambient of 17/18 outside.: new engine 1000miles old after running it in, 405ps on our dyno - the only stock uncleaned car that has dynoed over 400 on our dyno.

Really? From the air inlets (one in the grill and one in the fender), you see temps increase from an ambient of 18C all the way up to 36C as measured at the mass flow sensor? I understand a dyno pull is different than a highway data log, but my IAT's are rarely over 5C higher than ambient at full throttle. This is of course, with a airbox powerflap that is functioning OK.

[neckarsulm]

My IAT was 36 degrees at ambient of below 20

I have just checked my power flap as per SilverRS4's excellent sticky and it's only moving a few mil, Houston do I have a problem?

[Sims]

am I the only one who noticed sims NEVER gets involved in technical discussions?
no comments on timing, mixture as relates to deposits, ie, no impact, although he contends that it does...

only divisive, political, gibberish, to cause trouble...to inflame...
BS like the problem is 'German engineering' when the shocks are built by the Japanese...
or the attacks against Petrol Dave or P_G becasue we share an opinion on ocassion, and do not on others
you guys hanging your hat with his are seriously misguided or mislead...
I do not want a 'following', as it appears the 'messiah' is attempting to generate...

do not let him distract from the technical discussion
even if you don't agree with me (<1% vs >25% for dcr, deposit impact, HP rating, etc.) it's technical, not personal and vindictive like him....
after all, one sided technical discussions seldom bear fruit...

Art, It's wrong for you to bring your disagreements with me to this thread in an attempt to garner support. What I said was in light banter (in view of on-going GTR thread at present) with 2manytoys, and no diversion intended. I shall say no more on this thread.

[silverRS4]

Neckarsulm: The position of the flap with no vacuum is normally closed. So you are saying that during the function test that its not opening all the way? If it was stuck closed, you wouldn't see any drastic problems with IAT at full throttle, but you may be hurting mass flow at higher rpm's. If its stuck open, then yes, I'd say IAT's would tend to almost always be higher than they need to be. For example, when the car is moving at slow speeds, the engine is drawing in a fair amount of air from the engine compartment and the entire inlet system, including the tube the mass-air / IAT sensor is mounted to, gets heat soaked even more than it would normally.

In any case, a sticky flap would indicate that its not closing all the way and thats not good either. Time for emery cloth and a decent lubricant. You should be able to cycle the flap 15-20 times fully open and closed during the function test before your vacuum reserves deplete to make sure it moves smoothly. Good luck.

[lengster1]

My airbox flap isnt closing fully any ideas?