The Cold Start Thread.

User avatar
scotta
Posts: 3010
Joined: Wed Apr 11, 2018 4:28 pm

The Cold Start Thread.

Post by scotta »

Cant find if we've got one so ill start this here

E90 M3 at a local dealership



My old R26

User avatar
JLv3.0
Posts: 4784
Joined: Thu Apr 12, 2018 11:42 am

Re: The Cold Start Thread.

Post by JLv3.0 »

What's the agreed protocol? Videoing device placed facing the exhaust?
User avatar
scotta
Posts: 3010
Joined: Wed Apr 11, 2018 4:28 pm

Re: The Cold Start Thread.

Post by scotta »

JLv3.0 wrote: Mon Aug 20, 2018 11:13 am What's the agreed protocol? Videoing device placed facing the exhaust?
I believe that is the correct procedure yes. Even better if you've just removed the rear silencer!
User avatar
scotta
Posts: 3010
Joined: Wed Apr 11, 2018 4:28 pm

Re: The Cold Start Thread.

Post by scotta »

Mates 55 Earlier before we went a run.

User avatar
NotoriousREV
Posts: 6437
Joined: Wed Apr 11, 2018 4:14 pm

Re: The Cold Start Thread.

Post by NotoriousREV »

Middle-aged Dirtbag
User avatar
JLv3.0
Posts: 4784
Joined: Thu Apr 12, 2018 11:42 am

Re: The Cold Start Thread.

Post by JLv3.0 »



Love the way it hunts and chunters when it's cold - been like that since the Akrapovic was fitted.
User avatar
dan
Posts: 560
Joined: Wed Apr 11, 2018 11:22 pm

Re: The Cold Start Thread.

Post by dan »

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!

User avatar
Coaster1
Posts: 1819
Joined: Tue Apr 17, 2018 10:38 pm

Re: The Cold Start Thread.

Post by Coaster1 »

^^^ nice 8-)
User avatar
JLv3.0
Posts: 4784
Joined: Thu Apr 12, 2018 11:42 am

Re: The Cold Start Thread.

Post by JLv3.0 »

dan wrote: Thu Aug 23, 2018 9:28 amwhich you only get one go a day at.
More details on that one please!
User avatar
dan
Posts: 560
Joined: Wed Apr 11, 2018 11:22 pm

Re: The Cold Start Thread.

Post by dan »

JLv3.0 wrote: Thu Aug 23, 2018 9:42 am
dan wrote: Thu Aug 23, 2018 9:28 amwhich you only get one go a day at.
More details on that one please!
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.

Image

This is the full list of parameters i'm playing with to get the fuelling right for every occasion....

Image

Here's what i'm monitoring when I fire it up...

Image

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.
User avatar
JLv3.0
Posts: 4784
Joined: Thu Apr 12, 2018 11:42 am

Re: The Cold Start Thread.

Post by JLv3.0 »

Our hero 8-)
User avatar
dan
Posts: 560
Joined: Wed Apr 11, 2018 11:22 pm

Re: The Cold Start Thread.

Post by dan »

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 :lol:
User avatar
Mito Man
Posts: 9735
Joined: Wed Apr 11, 2018 4:27 pm

Re: The Cold Start Thread.

Post by Mito Man »

Seems piss easy.
How about not having a sig at all?
User avatar
GG.
Posts: 4607
Joined: Wed Apr 11, 2018 4:16 pm

Re: The Cold Start Thread.

Post by GG. »

scotta wrote: Mon Aug 20, 2018 11:11 am My old R26
I didn't realise they did a diesel R26! :lol:
User avatar
Mito Man
Posts: 9735
Joined: Wed Apr 11, 2018 4:27 pm

Re: The Cold Start Thread.

Post by Mito Man »

Most stuff sounds like a diesel on cold start unless it’s a V8 or v12
How about not having a sig at all?
User avatar
GG.
Posts: 4607
Joined: Wed Apr 11, 2018 4:16 pm

Re: The Cold Start Thread.

Post by GG. »

Mito Man wrote: Thu Aug 23, 2018 11:30 am Most 4cyl engines sound like a diesel on cold start unless it’s a 6, V8 or v12
FTFY.
User avatar
scotta
Posts: 3010
Joined: Wed Apr 11, 2018 4:28 pm

Re: The Cold Start Thread.

Post by scotta »

GG. wrote: Thu Aug 23, 2018 11:05 am
scotta wrote: Mon Aug 20, 2018 11:11 am My old R26
I didn't realise they did a diesel R26! :lol:
Image
User avatar
scotta
Posts: 3010
Joined: Wed Apr 11, 2018 4:28 pm

Re: The Cold Start Thread.

Post by scotta »

GG. wrote: Thu Aug 23, 2018 11:43 am
Mito Man wrote: Thu Aug 23, 2018 11:30 am Most 4cyl engines sound like a diesel on cold start unless it’s a 6, V8 or v12
FTFY.
ORLY

User avatar
JLv3.0
Posts: 4784
Joined: Thu Apr 12, 2018 11:42 am

Re: The Cold Start Thread.

Post by JLv3.0 »

That sounds AWFUL :lol:

Is it broken?
User avatar
GG.
Posts: 4607
Joined: Wed Apr 11, 2018 4:16 pm

Re: The Cold Start Thread.

Post by GG. »

That doesn't sound like a diesel - that just sounds like its broken :lol:

ETA - JL pipped me there :D

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.
Post Reply