Quote:
Originally Posted by turbotalon1g
I hear you on that one, but i don't know anyone that will dial all that shit in.
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Warning: This post turned into a long rant.
I have to dial in the airflow and deadtime on almost every DSMLink car that I do, especially if it's running a MAFT with it's poor metering. It might not be 100% perfect, since I only have a limited amount of time with the car, but I try to get it very close in the areas that you actually would drive in. Usually it's good enough that you could get by without an O2 sensor, I have done a bunch with bad or flaky O2 sensors that we just had to put the car into fulltime openloop anyways. DSMLink doesn't offer nearly as many MAF airflow points as an EPROM tuned ecu nor full fuel and timing maps, so you can't dial it in quite as finely.
I had the 4th or 5th DSMLink made and have been tuning them for a while. I know that playing with the timing slider in the 0-4000 RPM area can adversly affect your part throttle. That changing the fuel sliders usually does nothing until you are WOT and have a lot of airflow, I see tunes all the time where people try to use the fuel sliders in the lower RPMs to try to add fuel and it does nothing, often it they do nothing even at WOT until you have a few pounds of boost. I know about the 2G quirk of long term fuel trims affecting WOT fueling and how to fix it. I have also tuned DSMLink cars with no knock sensor, which actually sucks and defeats one of the main reasons to run DSMLink in the first place.
I can't tune a car that is broke though. 75+% of DSMs that come in for tuning have a major boost leak. Sensors need to actually be working right. They shouldn't overheat constantly, the cooling system needs to be able to pressurize to raise the boiling point, so no leaks, a good radiator cap and thermostat are usually needed. No thermostat or a stuck open one will make them take longer to warm up and then not cool as well once it's warmed up. If you are pushing coolant, then you probably have a blown headgasket, it isn't uncommon for a DSM to have a barely blown headgasket because of a poor sealing surface, bad install, knock or whatever and run perfectly fine and not smoke, but push some under boost which eventually leads to overheating when that space in the cooling system is now full of air. It usually doesn't hurt power either, it just annoying to have to fill it up all the time and have it start overheating every pass. BTW, I don't copper spray headgaskets either nor do I retorque headstuds. I have run over 40psi on cars without pushing any coolant, the surfaces need to be perfectly flat though and clean enough to lick. If you do want to spray your headgasket, copper spray isn't the thing to use, there are better options.
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