| ausmini https://ausmini.com/forums/ |
|
| Supercharger Heat Variation Effect on Air Fuel Ratio https://ausmini.com/forums/viewtopic.php?f=2&t=100928 |
Page 1 of 1 |
| Author: | MINI66 [ Fri Apr 30, 2021 9:32 am ] |
| Post subject: | Supercharger Heat Variation Effect on Air Fuel Ratio |
Hi there I am running an SC12 (normal draw through) at 12-14PSI on a 1275 with Mikuni HSR carb and just wondered if anyone had experienced idle AFR variations based on blower temps. It is bit of a pain to tune the idle (everything else is fine). After warming the engine up and taking a few low speed runs around town, including stopping at lights, I then tune for a target AFR of around 13.5:1. All good, let it idle for 5 min and it may drop to 13:1 when the blower heats up a bit. I can then take it for a run on the highway at say 120kph, the air flow cools the blower and when I pull up to a stop the idle AFR will be around 16:1 (which results in a rough lumpy low idle on an A series). Let it idle for 5 min and it will slowly creep back to 13.5:1. Just wondering if anyone has tried to cool the SC body on an SC12 in some way to keep the charge temps a little more consistent? Cheers Rick |
|
| Author: | Morbo28 [ Fri Apr 30, 2021 1:22 pm ] |
| Post subject: | Re: Supercharger Heat Variation Effect on Air Fuel Ratio |
You could run a water injection sprayer at the inlet to the blower that comes on at say 6psi of boost. That could take the edge off the heat? They are pretty cheap. My advice if you get it is to not worry about progressive systems, the cheaper on/off system is best for the Mini for reasons I can go into if you're interested. Edit: re reading this, I see it's actually heat at idle, so this solution won't help. VMax had a supercharger body cooler on theirs but not sure how effective it was. Sent from my Pixel 3 XL using Tapatalk |
|
| Author: | MINI66 [ Fri Apr 30, 2021 1:54 pm ] |
| Post subject: | Re: Supercharger Heat Variation Effect on Air Fuel Ratio |
Yeah thanks Morbo. I have seen that vmax setup and I think they discontinued it due to minimal effect? I notice that their most recently installed kits don't include this. I was thinking along these same lines though. The eaton blower that they use has a valley in the middle that makes it easier to create a water cooled heat sink area. They just glue on a water jacket kind of thing. I was just curious to see if anyone had done similar to an sc12. Due to the shape it would be a mission I reckon. Yeah I am not interested in the complications of water injection. I have no detonation at the moment with 14PSI and a fair bit of ignition advance too all good there. I could tune the idle to be a bit richer but am scared of fouling plugs in the Macca's drive through that has happened to me before. This colder weather is awesome for building boost but downside is how much it cools the blower. (I have thought of restricting air flow over the blower but that is a bit counter intuitive for a non intercooled setup) Especially when pushing the sc12 to 14-15psi cheers Rick |
|
| Author: | MINI66 [ Fri Apr 30, 2021 2:10 pm ] |
| Post subject: | Re: Supercharger Heat Variation Effect on Air Fuel Ratio |
Hey Morbo PS. Loved your supercharged deluxe build thread. I went through all the same stuff for this build back in 2006 but didn't have much to go off. I also had issues with engine temp at boost and ended up using the normal steel manual steel 16 blade fan, a 2 row aluminium china 50mm radiator, an aux rad (heater matrix) and a big 11inch Spal 1300cfm thermo in the wheel well with an aluminium cowl. Also sealed up the gap between the body cowl and the radiator with rubber door seal. (used the original rubber stipping for the NA mini) I have attached a pic of the setup. Might help someone (this is on my NA mini but the same setup) |
|
| Page 1 of 1 | All times are UTC + 10 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|