Summary

00:00 - Our next question comes from Lewis who's asked, can you talk about the kind of numbers you want to see in cold start tuning? Yeah absolutely, so cold start tuning is one of those topics that I think is quite misunderstood.
00:17 There's a lot of people really struggle to get an engine tune that will cold start really well.
00:22 So for me, this is one of my priorities, what I really want to do is replicate the way the engine starts from stock.
00:28 So basically regardless whether we're in the middle of summer or the middle of winter and there's snow on the ground, we should be able to reach through the driver's window, turn the key, have the car start up and idle perfectly without us needing to nurse the engine for the first few minutes with the throttle.
00:42 So the first point here with cold start tuning is it needs to be done after the rest of our fuel and ignition maps are dialled in because generally they will be multipliers or adders on top of our base fuel table numbers.
00:55 So this means that we need to really have a car for a few days in order to properly tune it at least at a bare minimum overnight.
01:03 Because of course once the rest of the tune is dialled in, the engine is going to be too hot and we won't be able to perform that cold start tuning.
01:11 So on top of this, we need to understand that there are a few different parameters, depending on the ECU you're tuning, generally there will be some additional enrichment that is applied while the engine is cranking, then once the engine has initially fired up there will be a post start enrichment and then a warmup enrichment so we need to understand how the ECU moves through these tables and we need to adjust them so that we are achieving our target air/fuel ratio.
01:35 Generally for cold start tuning, I will run the engine a little bit richer than I would at idle for example when it's at operating temperature.
01:43 We may be, for example, starting our engine under cold start conditions with the target air/fuel ratio somewhere in the region of maybe 13.5:1 and as the engine warms up, it'll lean out gradually to that 14.7:1 running point.
01:57 That question was taken from one of our free live lessons.
02:01 If you like free stuff, and you're the type of guy who wants to expand your knowledge, click the link in the description to claim your free spot to our next live lesson.
02:10 You'll learn about performance engine building and EFI tuning, and you'll also have the chance to ask your own questions which I’ll be answering live.
02:19 Remember it's 100% free so follow the link to claim your spot.