Richard.

My TT always seems to run rich first after my EPL tune and then also after my Sportec tune on the dyno when the engine was rebuilt, I guess there is nothing to do except get it retuned again, running on a lower Octane gas would be dumb right ?

Richard.

& by running rich I mean the exhaust tips are always dark black

993GT

not necessarily a bad thing, good to be on the rich side rather than lean...if you are worried I'd do some datalogging and contact EPL if required for an 'adjustment;..
Also check for boost/vacuum leaks before 'blaming' the tuning
Cheers,

Richard.

there are no boost leaks I'm seeing 1.2 BAR, the latest Sportec Map would be the issue (not EPL) any thoughts about running lower octane fuel ?

jumper5836

lower octane will cause the sensors to change the gas mixture and de-tune the hp. It will likely still run rich with less hp.

JG 996T

Have you actually logged or checked AFR?

Land Jet

Rich is safe, be happy.

Richard.

I'm aware its safer to run rich on higher HP, I'm concerned that I am not optimising performance that's all and my Ferrari tips are such a natural colour by comparison

Macster

Diagnosing engine mixture correctness by the darkness of the color of the exhaust tips is about as valid as estimating speed by the number of bugs smashed on the windshield.

If you suspect the tune is off you need to contact the company that offered it and ask it how to determine/double check the mixture is correct.

Do not run a lower octane of fuel than the minimum permitted by the tune. The risk is the timing can't be dialed back enough and the engine will experience detonation and suffer serious engine damage.

Kevinmacd

The tune probably changed the fuel curve to support the increase boost. Lowering octane should not even be considered since these tunes are based on octane assumptions. I agree looking at the black in the pipe is not a good way to come to a conclusion. No lead fuels produce black in the pipes as compared to the old leaded fuels that left a grey color. Does the car smoke a lot? I would think if you are not getting any CEL, the O2 sensor is providing the needed feedback to take into account the change in the fuel curve. Best method to determine the fuel air ratio is to measure it through diagnostic means! To compare to the Ferrari is apples and oranges. The Ferrari is a naturally aspirated engine!

Richard.

the car doesn't smoke apart from very briefly on cold start up for 30 seconds

Kevin

Richard, didn't you lose a engine due to a overboost detonation issue?

Why would you even think of using a lower octane fuel, when you have gone thru a major engine rebuild?

If you have question about the tuning and performance of your engine, contact Sportec. Get a datalogger and log your engine to see what your actual fueling is.. That will give you the information that you need vs guessing.

Richard.

thanks Kevin but Sportec were supposed to originally address this issue, do all tuned TT's have to run rich by default ?

Kevin

I think that you are in good hands with Sportec.

Every tuner has a different tuning method for fueling. With the Bosch ME7.8 the stock fueling map is NOT constant. The X50 and GT2 fueling maps are RICH.. The last target mapping cell prior to shifting is also very rich for the shift OVERRUN.. If you are shifting at Redline, the fueling map is rich.

As your plugs and MAF degrades over time. If your ECU is pulling timing from knock retard, fueling can be "dumped" richened to protect the engine. Again it's hard to see what your engine is doing without LOGGING your values.. By a datalogger and do a 4th gear to redline pull. Send the log to your tuner or post it on Rennlist and you will get some feedback. You can always run your car over to Sportec and run it on there dyno $$$

Richard.

Sportec are a set of guys who unfortunately do nothing for free, even if they didn't do it correctly first time round and I am certainly not in the mood to drop them another $1,000, after the last $55,000 (the majority of which was paid for by an insurance co for the engine rebuild) but I did pay separately for an ECU retune.