Jump to content
SAU Community

Recommended Posts

I have programable ECU and wanted peoples opinion on the best idle ignition timing to use, it's currently 14°.

I have idle probs sometimes but I have big injectors, light flywheel, big turbo and exh cam timing retarded that don't help. I have also played with fuel (dropped) to improve city cycle fuel econ. so I can easily increase it up again to get rid of problem but I want to be more smart about it.

Apart from trying it, will an increase in timing from 14° improve idle quality and reduce stalling etc?

Link to comment
https://www.sau.com.au/forums/topic/51659-idle-ignition-timing-s1-rb25det/
Share on other sites

I'm running a Wolf 3D on a Stagea RB25DET, standard injectorsa, but light flywheel. At idle (around 800), its got about 16 deg, but at the rev point below idle its got 19. Apparently produces more torque to pull the engine out of a stall.

I thought the timing for an RB25DET was 15 deg. I'm pretty sure thats what the Nissan sticker says under my bonnet. i have a very smooth idle... it has been set to 740rpm... according to my rsm it is never more then +-10rpm!!!

I have programable ECU and wanted peoples opinion on the best idle ignition timing to use, it's currently 14°.  

I have idle probs sometimes but I have big injectors, light flywheel, big turbo and exh cam timing retarded that don't help.  I have also played with fuel (dropped) to improve city cycle fuel econ. so I can easily increase it up again to get rid of problem but I want to be more smart about it.

Apart from trying it, will an increase in timing from 14° improve idle quality and reduce stalling etc?

I reckon you are on the right track, as I have backed by base timing of a little and it caused a slightly lower and rougher idle

I adjusted this using the idle control valve on the plenum, but I reckon a small increase in timing (say around 1 to 2 degrees) should make it better rather than worse

I adjusted this using the idle control valve on the plenum
Nothing to do with ignition timing. All it does is change the amount of air bleeding into the plenum at idle (closed throttle).

Thanks guys.

Actuall I should clarify, idle quality is OK, it just stalls under certain conditions with the current fueling I have.

I had a go on the way home from work....plenty of bloody idling opportunities!... and increased from 14° prgressively to 16°. Was funny though, woudl still stall sometimes but other time with all parameters the same it would be OK. The ECU has other idle functionality I need to play with so I'll keep ya posted.

Edit: Just read in book that 15-32° is typical for motors, so I'll jack it right up and see how it goes.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
    • You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine. Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.
×
×
  • Create New...