Audi A5 Forum & Audi S5 Forum banner
41 - 50 of 50 Posts

·
Registered
Joined
·
1,971 Posts
Discussion Starter · #41 ·
I was low on fuel, again, light on. Floored it on the motorway and it went into limp mode with just the EPC light on. Engine was running smooth, just no boost. The supercharger wouldn't come in, no boost according to my FIS control, scrolled down in the FIS to fuel pressure and that was normal at 5.2bar low side and 128bar on the high side, intake temp was only 51 C as I had the charge coolant pump running full in this hot weather. :) Got my FIS control running properly the other week, but I don't drive much as working from home, but it is really good, especially when something happens like limp mode as you can check the stats instantly reading from the CAN-bus. Exhaust and cats were at 750 C. The EPC light hasn't come on before and the engine light has never been on.

Came off the motorway, turned off and on, all back to normal. :) Got some expensive V power fuel (£1.51 now!!!) Pulled like a plane or train, whichever is the best analogy for zooming towards the horizon. :)! Ran VCDS and no faults. Guessing the EPC light is more a plug or coil pack miss fire or possibly a gap in fuel supply as it only had 10 miles left, oops.

Even though the 3.0 SC V6 runs hot, or seems too, this hot weather doesn't seem to affect performance. :)
 
  • Like
Reactions: HTB

·
Registered
Joined
·
673 Posts
So Dave, intake air temps. Have you seen any really high temps out on the road? What's your opinion on the charge cooler upgrade now?
 

·
Registered
Joined
·
1,971 Posts
Discussion Starter · #43 ·
So Dave, intake air temps. Have you seen any really high temps out on the road? What's your opinion on the charge cooler upgrade now?
Since fitting the FIS, I haven't been on a long drive so not got heat soak, well only after being parked. I've only done 30-45mins driving with some blasting on the motorway and it got to around 65 C. But when I've been parked up and come back to the car, it's been at 75-80 C! But as soon as I start the car and drive it does drop quickly to around 60-65C. On WOT it does initially drop by about 10C as the air rushes in and then starts to slowly climb as as it gets towards the redline. But the conclusion is, it's not hitting 80C as it did on the rolling road, but we did drive there, then wait a while, whilst it's strapped down. Then it's only run a little on the rolling road before going for it, so the heat soak won't have time to cool off. I reckon if the car was ran with some throttle to let the air in, but no heat producing boost for longer, then you might have a chance. But I think the pump will only run when on the throttle, maybe with boost, so unless you do the pump mod, it's not going to get chance to cool down.

From my limited drives, it seems to settle around 60C and drop initially when on WOT, but not seen the dirty 80C IATs, yet!

Got a universal heat exchanger on order, so will fit this and see what this does! For what it is and it does seem that we only experience limiting IATs on the rolling road, in the summer, I don't want to spend loads on a charge rad. The one I've ordered is the same as Merc racing was offering before they started to make specific rads for the 3.0T. I'm going with the stack route. I emailed a few places and it's basically £400+ for a big replacement rad. On Audizine, the stacked method appears to be just as good! The Jag XKR uprated rad, as far as I can tell is just a single pass. The uni rad I've ordered is a twin pass so the coolant has a longer trip/route on the cooling stage. For £145 for the rad, it's worth a punt! Most only went with a single large rad for aesthetics and a bit more cooling power. The combined surface area of the stacked route I'm going for is pretty much the same as the single large rad, so in theory it should provide the same cooling and stacked will also provide a 4 pass route.

I do want to try the rolling road again once it's fitted, just to see, but also want to wait until Autumn to get the best cooling for a map tweak. :)

Plus all fuels are going to E10 in September, so a remap maybe beneficial!? :) Might get more power as the guys do in the US using E85.
 

·
Registered
Joined
·
673 Posts
Ah that's interesting Dave. So you are piggybacking another charge cooler presumably on the top side of the crash bar?
I'm sure that would do the trick.
Any idea where you'll source some hoses from or will you just wait until it arrives and have a play?
 

·
Registered
Joined
·
1,971 Posts
Discussion Starter · #45 ·
Yeah, leaving the OE rad in, then putting the Uni rad on top. I'll gauge the position once I've got it, but there is only about 330mm from the top of the OE rad to the top where the slam panel cover is. So I'll see if the uni rad is the most exposed to air flow directly on top of the OE rad or better right at the top.

I'm going to get some 19mm aluminium piping (as you can get all sorts of sizes and bends etc on Ebay) and make the connections with straight hose as there will need to be a 180 degree bend out of the top of the OE rad into the bottom of the Uni rad, so don't want a hose to kink on that sharp 180 bend. Going to assess once I get the rad and what room is available. Might get some aluminium MIG wire to weld the pipes and mount points in the middle of the Uni rad as the mounts are top and bottom, so then I can bolt straight to the crash bar like the big single rads. But we'll see what the final fit is like after assessing and trial fits.

But researching the big rad kits, there is only so much cooling done upfront that the intercoolers in the supercharger then become the limiting factor! No point in spending thousands on a mahoosive charge rad when the small SC intercoolers still have a limit on how much heat they can soak out of the heated boost.
 
  • Like
Reactions: Smokey Joe

·
Registered
Joined
·
1,971 Posts
Discussion Starter · #47 ·
Me too!

Ps, the rear caliper covers are nearing final stages! Just need to get the samples cut and trial fit them :D
 
  • Like
Reactions: Smokey Joe

·
Registered
Audi S5 sportback
Joined
·
271 Posts

·
Registered
2015 S5 Coupe
Joined
·
291 Posts
So pulled the error codes tonight, and it's the same as last time:

Code:
15074 - Cylinder Disabling
          P130A 00 [096] - -
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 57111 km
                    Date: 2021.07.18
                    Time: 11:06:20

                    Engine RPM: 6902.50 /min
                    Normed load value: 100.0 %
                    Vehicle speed: XX km/h
                    Coolant temperature: 89 °C
                    Intake air temperature: 32 °C
                    Ambient air pressure: 1010 mbar
                    Voltage terminal 30: 13.789 V
                    Unlearning counter according OBD: 40
                    Misfires per 1000 revolutions of cyl. 1 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 4 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 3 intake manif. injection: 500
                    Misfires per 1000 revolutions of cyl. 6 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 2 intake manif. injection: 0
                    Misfires per 1000 revolutions of cyl. 5 intake manif. injection: 0
                    Engine torque: 456.31250 Nm
Interesting to note the RPM, 6902, which is quite high.

So it's cylinder 3 and I recon the coil pack will be my first port of call. I'll swap cylinder 3 with another as a test in the first place and see if the error moves.
 

·
Registered
Joined
·
1,971 Posts
Discussion Starter · #50 ·
Hi Tony, could also be a dodgy connection.
 
41 - 50 of 50 Posts
Top