Stuttering at Spa?

[shimmy]

For you guys running standard ecu maps that also have changed your back box and/or Cats you will be running lean at WOT and top end rpm....

The standard ecu map does not have a wide enough range of fuel adaptations to cope with the extra flow from the exhaust ie car runs lean at certain points through rpm range...

Wether or not this is enough to cause that much extra heat who knows, but yes it will cause extra heat!

However this lean running is not lean enough to cause damage as car will retard timing...only if it hears detonation though! To see if it is retarding timing plug in a GT1 and go for a drive while looking at the instant ignition timings screen...

Best get your car on a good dyno for a quick check of the AFR's Shimmy, or install an AFR guage which is more accurate and see what it's doing. You can also run the GT1 on the dyno to see the ignition timings...very interesting to see what the ecu is doing with them and how fast it changes the timings in each cylinder!!!

I have found that the AFR for the S54 should be in a range of between 12/1 or 13/1 mine run a steady 12.5/1 from about 2500 rpm...

as ive had my car thru loads of years and situations i know however that it has nothing to do with remap, nothing to do with exhaust (only item changed at some points was to 100 cell cats)

I will do some checks however and see what i can pick up

[cantfind1]

• Wide open throttle depletes intake manifold vacuum at the tip of the fuel injectors and in the fuel pressure regulator vacuum chamber. The spring closes the restriction valve to raise fuel pressure available to the fuel injectors. This maintains pressure differential (fuel flow through) for the fuel injectors.



From BmW sheets! I wonder if the fuel pressure isn't allowed to raise itself!

Take a look at this

http://www.unofficialbmw.com/images/m3engineelectronic2.pdf

You mean you think you have a problem with your pressure regulator, possibly a weak spring not closing the return line restriction?

Easy to check mate attach a fuel pressure tester to the rail and take it for a drive or on the dyno and see what pressure its maintaining at the fuel rail. Obviously ur looking for 5 Bar...

[shimmy]

You mean you think you have a problem with your pressure regulator, possibly a weak spring not closing the return line restriction?

Easy to check mate attach a fuel pressure tester to the rail and take it for a drive or on the dyno and see what pressure its maintaining at the fuel rail. Obviously ur looking for 5 Bar...

There are a large amount of E46M3 owners, especially in States, that seem to have high temps on track at 100% throttle on hot days. Nobody sems to have really cured it and most hide it with increased oil coolers (i can see that might work) but id rather solve it tbh.

I think that its something simple and to do with the age of the cars (something wearing out).

I think my APP does fuel pressure reading from the OBD so ill try that first this weekend and see what it records.

[cantfind1]

Cool let me know how you get on.....I think you may be right something is wearing the question is what......I think it may be old radiators.....old oil coolers becoming less efficient with age....

[shimmy]

Cool let me know how you get on.....I think you may be right something is wearing the question is what......I think it may be old radiators.....old oil coolers becoming less efficient with age....

My oil system is 100% new with engine change so not that and countless US cars have had new rads or aftermarket rads with no improvement.

It's gonna be a little more obscure than that and simply o fix, I betcha

[shane@mbtech]

My oil system is 100% new with engine change so not that and countless US cars have had new rads or aftermarket rads with no improvement.

It's gonna be a little more obscure than that and simply o fix, I betcha

try a fuel filter Shimmy, and if no joy, change the pump.

Ive got a tank here, I might disect it and see if I can fit baffles, to stop the fuel surge issues.

[alexk]

ignoring the fuel starvation on RHD crners at 1/4 tank fuel, i think the fuel system is the root cause of the high temps at 100% throttle on hot days that i and others have experienced. Even FLOW got a bit at ZOLDER.

could the fuel at 100% THROTTLE be running short and running the engine lean and therefore hotter thus affecting oil temps and eventually water temps?

Christoforos from Cyprus resolved the temp issue when he re-mapped the ECU with the factory map.
The car was re-mapped.

So what stats do we want to see with the GT1 guys ?
I can do a test.

[83SY]

I got that in exactly that place, assume was fuel starvation, with me went away if I filled up.

+1 keep it min 3/4 tank

[ac427]

What is the recommended pump these days?

Has anyone used an HRC fuel pump?

Is the Bosch 044 too large to fit?

[Mike RT4]

What is the recommended pump these days?

Has anyone used an HRC fuel pump?

Is the Bosch 044 too large to fit?

The 044 is an external pump, the CSL uses an internal pump.

You would have to make a "surge tank" that the OEM pump feeds to and the the 044 takes the fuel from the surge tank to the fuel rail.....

[cantfind1]

Careful fitting aftermarket pumps, whether internal or external. You will change the fuel flow, normally will require remap if you fit a higher flowing pump.