Audi v8 down on power??
Discussion
Separate problem MRC believe but as it happens so so rarely at mo they told me it’s not worth finding the fault because to find the fault will/could involve hours of removing virtually all electrical modules/ecu’s to find it... basically a needle in an EXPENSIVE hay stack if I got MRC do it!! It’s only happened twice in about 5-10000 miles...
Nick
Nick
The saga continues....
This is message I sent to MRC today after after going back on local dyno....
“Hi Sarah, this is Nick Davies.... you guys had my Audi s5 4.2 in a few weeks ago for health check on dyno and found I had a broken manifold flap control actuator.
Could you give me a call ASAP please as I want you guys to have another look at it, I’ve had part fitted locally and all seemed fine till I put it back onto local dyno. I’ll email you the before and after graphs to see what you guys think but it now seems it is stuck in the “power” mode as it’s not making as much low down torque as before???
The new actuator is definitely moving as I watched it kick in when car was on dyno .
I’m just wondering if it’s been fitted incorrectly?? Car does feel quicker though🤯
I’ve added the before and after dyno print outs they’re are so different
“
BEFORE
AFTER
My brain is fried.... car feels faster, will do 60 in under 5 secs yet is down 20 bhp and 50 Nm of torque??
This is message I sent to MRC today after after going back on local dyno....
“Hi Sarah, this is Nick Davies.... you guys had my Audi s5 4.2 in a few weeks ago for health check on dyno and found I had a broken manifold flap control actuator.
Could you give me a call ASAP please as I want you guys to have another look at it, I’ve had part fitted locally and all seemed fine till I put it back onto local dyno. I’ll email you the before and after graphs to see what you guys think but it now seems it is stuck in the “power” mode as it’s not making as much low down torque as before???
The new actuator is definitely moving as I watched it kick in when car was on dyno .
I’m just wondering if it’s been fitted incorrectly?? Car does feel quicker though🤯
I’ve added the before and after dyno print outs they’re are so different
“BEFORE
AFTER
My brain is fried.... car feels faster, will do 60 in under 5 secs yet is down 20 bhp and 50 Nm of torque??
I understand what your saying but knowing now what I know about the part that has been replaced and how the manifold flaps work, to my mind now it seems it has gone from one extreme to other by that I mean I was informed by MRC the car/flaps were stuck in “Torque” phase so that’s why I was getting stock peak torque at the correct rpm (approx 3500 revs) but the actuator wasn’t moving the the flaps at around 4800 revs (to put runners into power mode) making power tail off whey earlier than it should.
But now after fitting new flap actuator torque is really low but you can now see on the graph the “power phase” is kicking in yet power is lower??
I just feel something still isn’t right, the graphs are so different, I’m wondering if the intake was reasembled incorrectly after it was carbon cleaned?
The mechanic that fitted new actuator did say the car was still throwing a fault for the flap but because it felt more lively I thought nothing of it ??
Is it even possible for a 1650kg 4wd car with 300 bhp to do a sub 5 sec 0-60 ??
But now after fitting new flap actuator torque is really low but you can now see on the graph the “power phase” is kicking in yet power is lower??
I just feel something still isn’t right, the graphs are so different, I’m wondering if the intake was reasembled incorrectly after it was carbon cleaned?
The mechanic that fitted new actuator did say the car was still throwing a fault for the flap but because it felt more lively I thought nothing of it ??
Is it even possible for a 1650kg 4wd car with 300 bhp to do a sub 5 sec 0-60 ??
I agree but my point is you would need X amount of bhp the achieve this.... the facts are after fitting new actuator car is down ANOTHER 20 horse yet car is over a second quicker to 60 (pointless I know) and 2 seconds quicker to 100...
the only reason I’m questioning it is because the graphs are SOOOO different and to me it now looks like car/flaps is stuck in power phase .... if the graphs were similar I’d prob just be happy that car felt quicker.... but to have peak torque at 5200 is just not right for this engine.
I’m deffo not chasing numbers, if I was I certainly picked the wrong platform.... hardly any gains to be had from this V8!!
the only reason I’m questioning it is because the graphs are SOOOO different and to me it now looks like car/flaps is stuck in power phase .... if the graphs were similar I’d prob just be happy that car felt quicker.... but to have peak torque at 5200 is just not right for this engine.
I’m deffo not chasing numbers, if I was I certainly picked the wrong platform.... hardly any gains to be had from this V8!!
So should be leaving MRC with right amount of horses today....
In the last week car was MOT’d, coolant system pressure tested and compression test carried out ...ALL GOOD.
So MRC has just told me that whoever had the Manifold apart to do carbon clean have put it back together incorrectly, putting flaps in the wrong way round
Hopefully they can do It this afternoon!
Why oh why does it come back to bite me in the arse every time I go cheaper option (was £500 where as would have been 800 here)
In the last week car was MOT’d, coolant system pressure tested and compression test carried out ...ALL GOOD.
So MRC has just told me that whoever had the Manifold apart to do carbon clean have put it back together incorrectly, putting flaps in the wrong way round
Hopefully they can do It this afternoon!
Why oh why does it come back to bite me in the arse every time I go cheaper option (was £500 where as would have been 800 here)
So inlet manifold was scrap.... quoted £2600 from Audi, so that was a no go... managed to source one from AUTODOC in Germany for £1150 .
Car was left at MRC last week, they contacted me today to let me know new manifold has sorted everything.... I knew something weren’t right...
before and after dyno....
That should feel like night and day now.... this will hopefully make this car a keeper now as was considering something a little more nippy... the extra grunt should scratch that itch, for a while
Car was left at MRC last week, they contacted me today to let me know new manifold has sorted everything.... I knew something weren’t right...
before and after dyno....
That should feel like night and day now.... this will hopefully make this car a keeper now as was considering something a little more nippy... the extra grunt should scratch that itch, for a while
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