Jump to content
SAU Community

Recommended Posts

10 hours ago, MBS206 said:

No cats will keep discolouring the rear bar. Sends white paint a weird yellow stain.

Cut and polish normally gets it out, but you'll be doing that every fortnight I found.

Not sure I will have much paint left if I do that … I am going to do my mirrors shortly with some n45 primer from dr beasley then ceramic coat them. The rear has been ceramic coated already after the paint. 
 

going to put the high flow back on but just need a tuner to help me and mine is out of town for the next two months or more.  Just worried about the ignition timing. 

1 hour ago, GTSBoy said:

Definitely needs ceramic coat and fresh wax every week.

And cats. Running with no cats is a (unt act.

Problem with putting them back on my ignition timing with the tune might get screwed up. What u think? 

55 minutes ago, Sleepergm said:

Problem with putting them back on my ignition timing with the tune might get screwed up. What u think? 

I'd be surprised if it's a problem. A highflow cat doesn't present a massive restriction. You'd have to be tuned on the ragged edge for there to be any likelihood of something going wrong.

  • Thanks 1
14 hours ago, Sleepergm said:

Not sure I will have much paint left if I do that … I am going to do my mirrors shortly with some n45 primer from dr beasley then ceramic coat them. The rear has been ceramic coated already after the paint. 
 

going to put the high flow back on but just need a tuner to help me and mine is out of town for the next two months or more.  Just worried about the ignition timing. 

If the slightly higher internal EGR caused by a high flow cat causes detonation your tuner was way, way, way too aggressive to begin with. Timing scatter is a problem unless you go to a crank trigger, winter vs summer blend has different octane, list goes on.

  • Thanks 1
8 hours ago, joshuaho96 said:

If the slightly higher internal EGR caused by a high flow cat causes detonation your tuner was way, way, way too aggressive to begin with. Timing scatter is a problem unless you go to a crank trigger, winter vs summer blend has different octane, list goes on.

So you’re saying pretty safe to put back on the high flow. I guess I will lose alittle horse power which is fine. Never heard of timing scatter? My idle has been an issue running rich since I put on a custom intake with smaller pipings so not sure how it will react to the high flow cat also - would add some more back pressure to the system no? 
 

Thanks 

22 minutes ago, Sleepergm said:

Never heard of timing scatter?

The stock Nissan CAS gets very messy at high rpm, particularly with bigger cams/springs, and most aftermarket ECUs don't do as good a job of filtering the noise as the OEM ECU somehow manages to do. So you get "scatter" in the timing signals that can be really destructive to the ECU's knowledge of engine position. And so you can get spark firing many degrees early, leading to catastrophic detonation events.

10 minutes ago, GTSBoy said:

The stock Nissan CAS gets very messy at high rpm, particularly with bigger cams/springs, and most aftermarket ECUs don't do as good a job of filtering the noise as the OEM ECU somehow manages to do. So you get "scatter" in the timing signals that can be really destructive to the ECU's knowledge of engine position. And so you can get spark firing many degrees early, leading to catastrophic detonation events.

I’m running links ecu and an upgraded crank sensor. So I guess I have less chance of this. 

29 minutes ago, Sleepergm said:

I’m running links ecu and an upgraded crank sensor. So I guess I have less chance of this.

Probably. But keep in mind that all Joshua was saying that because of things like timing scatter, and many other related and unrelated things, tuning too aggressively should be avoided. Hence why both he and I said that fitting the cat shouldn't cause you to suddenly fall into the danger zone.

1 minute ago, GTSBoy said:

Probably. But keep in mind that all Joshua was saying that because of things like timing scatter, and many other related and unrelated things, tuning too aggressively should be avoided. Hence why both he and I said that fitting the cat shouldn't cause you to suddenly fall into the danger zone.

Yeah its tuned relatively conservatively being dynoed at 525hp with every bolt on and top end of the motor built wtih HKS vcam and springs etc. 

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

    • @Haggerty this is your red flag. In MAP based ECU's the Manifold pressure X RPM calculation is how the engine knows it is actually...running/going through ANY load. You are confusing the term 'base map' with your base VE/Fuel table. When most people say 'base map' they mean the stock entire tune shipped with the ECU, hopefully aimed at a specific car/setup to use as a base for beginning to tune your specific car. Haltech has a lot of documentation (or at least they used to, I expect it to be better now). Read it voraciously.
    • I saw you mention this earlier and it raised a red flag, but I couldn't believe it was real. Yes, the vacuum signal should vary. It is the one and only load signal from the engine to the ECU, and it MUST vary. It is either not connected or is badly f**ked up in some way.
    • @Haggerty you still haven't answered my question.  Many things you are saying do not make sense for someone who can tune, yet I would not expect someone who cannot tune to be playing with the things in the ECU that you are.  This process would be a lot quicker to figure out if we can remove user error from the equation. 
    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
×
×
  • Create New...