Cant find if we've got one so ill start this here
E90 M3 at a local dealership
My old R26
The Cold Start Thread.
Re: The Cold Start Thread.
What's the agreed protocol? Videoing device placed facing the exhaust?
Re: The Cold Start Thread.
Mates 55 Earlier before we went a run.
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NotoriousREV
- Posts: 6436
- Joined: Wed Apr 11, 2018 4:14 pm
Re: The Cold Start Thread.
Love the way it hunts and chunters when it's cold - been like that since the Akrapovic was fitted.
Re: The Cold Start Thread.
This a brand new 2.2 k20, its only run for about 3 hours so far, fired up for the first time on the weekend and so far have spent many hours just getting it to idle and start as it’s on a different ecu to those I usually use so I’m doing everything from scratch including cold start, which you only get one go a day at.
Here’s this mornings cold start, for a 300hp n/a engine on massive throttle bodies and no idle control valves to start on the key like this is not easy to achieve!
Here’s this mornings cold start, for a 300hp n/a engine on massive throttle bodies and no idle control valves to start on the key like this is not easy to achieve!
Re: The Cold Start Thread.
Cold start isn't just cold coolant and cold air, its also massively affected by whether or not the engine has already been run, whether the port walls are completely dry or not and a bunch of other factors. The first start of the day needs significantly more fuel dumped down the ports to wet them before it'll start, each subsequent start needs less and less as temperature increases. To properly replicate cold start you only really get one go a day, or at best one go in the morning and another at night, as long as you haven't run the engine all day.
This is the cranking fuel multiplication table, each value is a multiplication factor of the overall injector pulse time with 2 being double the usual pulse time. You'll see for the first couple of revolutions of the engine whens its cold its pumping over 100% more fuel down the ports yet within a dozen revolutions its down to 30% and dropping fast.
This is the full list of parameters i'm playing with to get the fuelling right for every occasion....
Here's what i'm monitoring when I fire it up...
During my brief stint at JLR running the timetable for prototype cars I got a good insight in to just how many hours are spent tuning this kind of thing, when you add up all of the people and hours they spend you quickly get into decades so its no wonder OEM cars start on the key every single time no matter the conditions.
Re: The Cold Start Thread.
I shut it down immediately after that video and didn't touch it, so its as cold as it was before, but i've just started it again an hour later and this time it catches quicker and is more responsive as the fuel hasn't evaporated from the port walls.
All I have to do now is get that absolutely perfect for every imaginable condition
All I have to do now is get that absolutely perfect for every imaginable condition
Re: The Cold Start Thread.
Most stuff sounds like a diesel on cold start unless it’s a V8 or v12
How about not having a sig at all?
Re: The Cold Start Thread.
That sounds AWFUL
Is it broken?
Is it broken?
Re: The Cold Start Thread.
That doesn't sound like a diesel - that just sounds like its broken
ETA - JL pipped me there
I really can't stand the modern generation of farty poppy upshift turbo engines. The Merc ones sound especially retarded.
ETA - JL pipped me there
I really can't stand the modern generation of farty poppy upshift turbo engines. The Merc ones sound especially retarded.
Last edited by GG. on Thu Aug 23, 2018 12:34 pm, edited 2 times in total.