Mistakes were made, my R34 Story

[MBS206]

1 hour ago, GTSBoy said:

That's the thing. Especially at idle, changing the cam angle by that much could be spewing more fuel out the exhaust courtesy of everything happening that bit later. More fuel also means more air (if the fuel didn't burn, then neither did the O2) and so the O2 sensors can start to tell interesting but misleading stories.

And the specifics of what is happening could easily be affected by everything else you changed as well. And it could be dynamic, where a few revs more or less could somewhat change how the engine is breathing.

I agree, and yet my "HRM " hat is also on, as his wideband is in disagreement with the narrowband where they used to play closer attention to each other.

[GTSBoy]

8 minutes ago, MBS206 said:

I agree, and yet my "HRM " hat is also on, as his wideband is in disagreement with the narrowband where they used to play closer attention to each other.

Yeah, but the narrowband is truly narrowband. So you take it out of the linear zone and it is effectively nonsense. And that linear zone is so literally narrow, that nonsense is not very far away. Unless they are flicking back and forth across the stoich point, for real, under actual control, they can't be trusted for anything except entertainment value.

[soviet_merlin]

So you had a car that by all accounts drove well and survived track days, and that was looking great after months of being stuck at a paint shop. Some might call that a finished project.

But you decided this is not quite right. So now the car does not run anymore. And the engine doesn't fit anymore. And the body parts don't match anymore.

But, this is progress somehow.

Greg, I think your subconscious does not like you and does not want you to drive this car.

(I know I know, this whole escalation was not intended, but man, what a rollercoaster)

[The Bogan]

8 minutes ago, soviet_merlin said:

So you had a car that by all accounts drove well and survived track days, and that was looking great after months of being stuck at a paint shop. Some might call that a finished project.

But you decided this is not quite right. So now the car does not run anymore. And the engine doesn't fit anymore. And the body parts don't match anymore.

But, this is progress somehow.

Greg, I think your subconscious does not like you and does not want you to drive this car.

(I know I know, this whole escalation was not intended, but man, what a rollercoaster)

[Kinkstaah]

33 minutes ago, soviet_merlin said:

So you had a car that by all accounts drove well and survived track days, and that was looking great after months of being stuck at a paint shop. Some might call that a finished project.

But you decided this is not quite right. So now the car does not run anymore. And the engine doesn't fit anymore. And the body parts don't match anymore.

But, this is progress somehow.

Greg, I think your subconscious does not like you and does not want you to drive this car.

(I know I know, this whole escalation was not intended, but man, what a rollercoaster)

So... the whole idea was to upgrade the power of the motor from stock. The motor I bought with the gearbox had 'some' stuff done to it in the past, but it wasn't as well thought out/what I had wanted to do. The stock heads typically are a big restriction on LS's and need porting to unlock quite a lot of power.

You can then go a bit silly with aftermarket castings to get more, aftermarket intake manifolds for a little more, and then porting those for more. <- We are here.

Nobody in Australia really goes down this path (for some reason). It might* make 3kw or something more than doing things the tried and true path for 10X the cost. So that's probably why - I wouldn't even recommend it to people, the money was and is likely better spent on just CNC'ing the stock heads and putting a 6.3L stroker kit in.

I didn't want to go down the 'normal' path and then think:

But if I'd just done a bit more - I could have had a slightly better result.

I assumed the heads were running out of flow and it always annoyed me - Turns out the previous installer advanced the cam 6 degrees so this is likely why it was coming on earlier and running out of puff earlier than advertised.

The body panels were just lack of planning/no information on this anywhere on the internet and the fact they came out different was annoying. From test fitting the guard it appears I could have gotten away with GTR guards only, but I got the bonnet and raisers and everything else as well for a pretty decent package deal.

[Kinkstaah]

51 minutes ago, GTSBoy said:

Yeah, but the narrowband is truly narrowband. So you take it out of the linear zone and it is effectively nonsense. And that linear zone is so literally narrow, that nonsense is not very far away. Unless they are flicking back and forth across the stoich point, for real, under actual control, they can't be trusted for anything except entertainment value.

The previous switchover point was 501mv. The stock value is like ~360. They now were idling at about ~880.

The thing is, most people get a false lean condition. I am getting false rich conditions. This isn't a quirk of terminology, most cam upgraders get awful fuel economy because the O2's read false lean and add fuel - Mine are attempting to aggressively subtract fuel.

[GTSBoy]

6 minutes ago, Kinkstaah said:

The previous switchover point was 501mv. The stock value is like ~360. They now were idling at about ~880.

The thing is, most people get a false lean condition. I am getting false rich conditions. This isn't a quirk of terminology, most cam upgraders get awful fuel economy because the O2's read false lean and add fuel - Mine are attempting to aggressively subtract fuel.

Messing with narrowband switchovers is a terrible bandaid. I don't want to think about it.

You are a cam "upgrader" only in concept. As you said, your new cam is actually smaller, so it's technically a downgrade. OK, likely a very small downgrade, but nevertheless. But the big thing that will be the most likely suspect is the change of the advance angle. That change could be equivalent to a substantial decrease in cam lobe duration. I haven't gone to the effort of trying to think about what your change would actually cause. But until someone (you, me (unlikely), Matt, someone else) does so and comes to a conclusion about the effect, it remains a possibility that that is the change that is causing what you're seeing.

[Kinkstaah]

In the context of cam 'upgrader' I mean generally people who upgrade headers/cams - not my specific change.

I mean it makes sense that if I had a bigger cam, I may get more false lean readings.
So if I went smaller, I'd get less false lean readings.

To a point where perhaps stock.. I'd have no false lean readings, according to the ECU.

But I'm way richer than stock. My bigger than normal cam in the past also was giving false rich leanings.
It's rather odd and doesn't add up or pass the pub test.

Realistically what I want is the narrowbands to effectively work as closed loop fuel control and keep my AFR around 14.7 on light sections of the map. Which is of course the purpose of narrowband CL fuel control. So if I can change the switch points so the NB's target 14.7 (as read by my WB) then this should be fine.

Haven't actually tested to see what the changed switchpoints actually result in - car needs to be in a position it can idle for awhile to do that. I suspect it will be a troublesome 15 min drive home with lots of stalling and way too rich/lean transient nightmare bucking away for that first drive at 2am or whevener it ends up being.

Hopefully it's all tune-able. Realistically it should be. This is a very mild cam.

[GTSBoy]

I'd be installing 2x widebands and using the NB simulation outputs to the ECU.

[Kinkstaah]

1 hour ago, GTSBoy said:

I'd be installing 2x widebands and using the NB simulation outputs to the ECU.

I mean I can be OCD'y but this is really over the top. At that point why not just run a full wideband fuel controller? Especially if you run 3 widebands.

The system works pretty well, which is trimming low load stuff to be within a few percent of the base map. Pre-engine _change_ the base map was only 1-2% off, depending on ambient temp, elevation, etc.

Under load the LS is really very straightforward to tune, enough that a wideband closed loop would be overkill. If I really cared (and I hope I don't) I can always just go back to the MAF system the car actually came with. Which does all those nice calculations for me (temp, altitude, etc), now that you can buy 102mm MAF's that do not cause restrictions.

[GTSBoy]

1 hour ago, Kinkstaah said:

I mean I can be OCD'y but this is really over the top. At that point why not just run a full wideband fuel controller? Especially if you run 3 widebands.

Well, you've already got one of them, so you only need to add one more.

C'mon, you know you want to. Deep down your inner masochist is just aching to punish your bank account a bit more. Just a bit more.

[MBS206]

Whats a couple of hundred dollars to protect a multi thousand dollar engine that is going to have a Gregged water pump on it soon...

[Kinkstaah]

I actually have a replacement bosch 4.9 (from mx5mania!) to replace my current 4.2 one when/if it dies. It did weird shit once so I pre-emptively got a new kit. I also do not remember where I put it after losing it for about 18 months. I think I left it in a brake box.. which left it with brake stuff.

In any case no. I much like how the OEM sensors talk to OEM ecu with OEM wiring and don't actually know if what GTSBoy said is even possible. 

[Kinkstaah]

MR HAMMER has said his piece.

Painted up to avoid Rusty Rusty.

Actually lines up well. (i.e it lines up the same as the unmolested GTR guard).

Turns out the GTR Strut brace does foul on the bonnet vents ever so slightly. May need a little bendy bendy if intended to keep using with a strut brace. So spacing it out to clear the FAST102 is not an option.

Annoyingly, the bonnet vents also foul on the heater lines running over the engine. Given this engine does not EVER require a heater, a delete loop is going to be used. Don't worry, the defogger uses the AC. The heater is basically "Do not use the aircon and turn the fan on". It will still be effective, I promise.... once I get the system regassed...

Will have to revisit with unvented bonnet I suppose, and suitable strut brace.

There's plans to do this and other things tonight and bleed brakes (there was a weep) and put the bumper back on, and take Good Friday morning - Because troubleshooting on the side of the road limping it home at midnight tonight is ... not very smart.

[Kinkstaah]

Alright. Many little things have been sorted and the car successfully drove home with an incredibly huge exhaust leak.

Unsure if it's simply been awhile, but new heads and cam and intake sound f**kin awesome. It might only be me that notices it though, and it's hard to tell from a 15 minute gauntlet run home and attempting to bleed the radiator.

Undertrays on, tools out, road brake pads in, idle un-f***ed, time to do some road tuning. From my commute around town it sounds and drives *really* nice (with a max of like 35% throttle). It'll go to a dyno for a proper before and after once the tune is more roughly dialled in.

And @Dose Pipe Sutututu I did learn how to do a proper chop tune at idle. I did indeed even do it, but the car shaking around at idle from the driverr seat made me make it smooth again.. I feared for my engine mounts and clerances to engine bay jank. . After the exhaust is fixed I may mess around with it more. I'm just happy to have it drive around without bucking or stalling which is a WIP.

[Dose Pipe Sutututu]

Best chop idle FTW, just add an idle timing hole lol

[Kinkstaah]

Nah, apparently the way to do it is just mess with how much timing the engine uses to try to correct idle. So it massively undershoots, then overshoots, then undershoots, then overshoots. So timing is going from 5deg to 45deg to 5 deg to 45deg.

But I kinda prefer the car to not lurch around and have a dependable idle. Given it didn't idle for shit and stalled about 7 times on the way home, still yet to drive it for the 2nd time to see if it's fixed.

[The Bogan]

Noice

Once exhaust leak is sorted post vids for audible sexy time

The thing should be a laugh riot to drive

[Dose Pipe Sutututu]

1 hour ago, Kinkstaah said:

Nah, apparently the way to do it is just mess with how much timing the engine uses to try to correct idle. So it massively undershoots, then overshoots, then undershoots, then overshoots. So timing is going from 5deg to 45deg to 5 deg to 45deg.

But I kinda prefer the car to not lurch around and have a dependable idle. Given it didn't idle for shit and stalled about 7 times on the way home, still yet to drive it for the 2nd time to see if it's fixed.

That's why it's lurching, idling shit, and stalled 7 times.

Your approach is not ideal, it's literally idle hunting. Let's say your normal idle timing is 20° 

You would approach the idle timing table like this 

800rpm 20°

900rpm 20°

950rpm 0°

1000rpm 20°

So when your car hits the 950rpm cell, there isn't enough torque so it falls down to the 900rpm cell which has enough timing to produce the torque to reach the idle target again.

Then you'll need to dumb down the PID for the idle control motor to essentially ignore the 950rpm cell.

There's an art to great braps, when you don't have the option to advance an intake cam at idle.

@GTSBoy going to be real mad 🤣

[GTSBoy]

2 hours ago, Dose Pipe Sutututu said:

@GTSBoy going to be real mad

Not mad. Just disappointed.