Timing retard amount...

[Powertechn2]

This may be a stupid question, it likely is answered here somewhere too, I did try to search and kept coming up with old dead unrelated posts, some dating back to 2003...
So, here goes.

How much timing retard is acceptable, and what factors change the varying amount of acceptable retard?

So, I did a bunch of work to the car last weekend, finally took it to work after a buddy was giving me a hard time. Got the air bag hoses fixed, a ton of vac lines replaced, installed the dump block off, and a shitton of miscellaneous stuff that was necessary.

Long story short if you don't care to read, I don't want any TLDR responses, so. reading 890 for mv I guess of the 02, which I know should be like mid 700's, and 1.2 timing retard, this went up as the car got hot, highest was 1.7... Car currently for some reason has a 195 tstat in it.

What is acceptable and what is danger zone when it comes to timing retard?


**Now for those who care to read on...
Found the nut on the boost control rod was loose, figured this might be why boost was fluctuating lower the more I drove the car. Also knew the builder 10 years plus ago would run 16psi on 93 octane (pre-10% ethanol) and 55psi static fuel pressure....
So, tightened the nut, gave a turn or so to the rod as I knew it was down on boost and the last guy was messing with all sortsa things and he was an idiot.
Also found the jam nut on the fuel pressure regulator was loose, was only at 37 psi.

Thought the car was about to run out of fuel on the way to work, had hoped it was low even tho the gauge read 1/2ish tank, it would fluctuate around a lot and tapping on the tank sounded really low. Added 6 gals of 93 and the damned thing is now at near full. Damn. Last guy said he had put a mix to be about 98 octane, but not really sure about this, it was in fall, said he added stabil, also unsure. Going to drain tank and run in the tractor before I swap injectors and chip to newer chip.

Found out car has a precision ta60 turbo, front mount that I think says precision on the side, was hard to read due to 10 years of dust and dirt, comp 212/212 cam, th down pipe, lt maf with translator. Trans was built by a guy in or near Roseville Mi, was supposed to be a great 2004r trans builder back then) has trans brake as 1st gear, 3000rpm 9 inch stall (had message stored in phone, kinda ran it over with my truck so going off memory), has 280 or 300lph fuel pump, heads are p&p cast, roller chain, upgraded valve springs... I fixed the hot wire also... Also has some unknown headers.

Car idled horribly and would stall, sometimes backfire soooo loud that on the way to work it did the backfire stall deal and as everyone turned their heads at me I just turned around and looked around like wtf was that as the car coasted in neutral to the light...
Fixed all the vac lines and a buncha stuff, found vac lines the middle previous guy tried to fix that seemed to just go nowhere other than to another melted vac line hanging down
Now the car idles, doesn't stall (hasn't yet anyways)...

So, work in progress.

 

[earlbrown]

No timing retard is acceptable.

 

[Powertechn2]

the guy that had built my car said what I had readings of was acceptable and then said it depends on many different parameters. I was kinda like ummmmmmmmmmm.....????

 

[earlbrown]

If it's false knock, it only hurts your performance and you're ECM get's compromised information as the knock reporting devices aren't accurate.


In a world where 'small amounts of knock (not knock retard) is OK, then it depend on how much power you're making and you're build quality. If you have a bone stock engine, full roller with all forged internals at 12psi.... then a little bit of knock isn't going to hurt you in real world conditions.....


a cast crank, high mileage engine running alcohol and high boost making over 100hp per hole will come apart at that same amount of knock.

I guess the 'parameter' in question is if your engine is going to barf it's guts all over the road. :\


Moral of the story, avoid false knock and tune for 0 detonation. Nobody goes faster with a retarded ignition map.

 

[Mr.Spool]

no knock,false knock could be downpipe hitting the frame,tranny mount, exhaust etc.gotta fix it either way.a wideband sensor would show how the tune is when you encounter knock.

 

[Powertechn2]

The retard was under extremely rich conditions, the guy who had built the car ran it down the track more times than I could likely imagine so that is why it threw me off when he said what I was seeing wasn't bad.

I assume it is false knock, I also know the coil seems to not be able to handle it's own at higher rpms.

There is a ratchet strap holding the drivers side of the engine which I am unsure as to why it is there, I remember asking about 10 years ago and he said it needed to be there to prevent false knock.

I think there is a wideband O2 installed, haven't crawled under to check, but found an empty bosch wideband box under the pass seat.
I actually have a wideband afr kit from dynojet that I have for tuning the quad, might just throw it on the car, might have to extend the harness as it is made for m/c installation.

If ignition was not firing under the pressures/rpm, could that itself cause a false knock/retard situation?


I am assuming it is stock turbo crank, I know the car held up under 22lbs boost at the track w/110 , he said 24 was the head gaskets limit and that he found that out twice...

Wish I knew more about the internals, the guy is a good friend of mine and answers whatever I ask when he remembers what he did lol.


Also thanks Earl, you pretty much answered what I was looking for as I was unsure what he meant by differing parameters

 

[earlbrown]

The ratchet strap is installed with the hope of fortifying the DS motor mount. Since it's nylon and not metal, the science is that it helps avoid sharp metallic 'bangs' when loads get applied abruptly.

If you're ignition if flaking out at high RPMs it don't necessarily cause detonation, but ignition dropping out when cause the A/F to read richer than it actually is.


Adding extra fuel has been a common way to dry and suppress detonation for years. Up to a point it actually works (kinda). By throwing in more fuel than you actually need, the burn isn't as hot. So with less heat, you have a lower cylinder temp and less chance of spontaneous combustion. (of course, with less heat, you have less HP and higher fuel consumption). The other 'benefit' of throwing too much fuel into the engine is the chemical intercoolling you get from phase change. Liquid fuel requires heat from the cylinder to change from a liquid to a gas. Throwing in extra fuel will absorb more heat. Couple that with a less than stoic burn, and you're on the way to avoiding the dreaded ping!

That only works up to a point though, detonation resistance goes down as you add fuel, up until the point that it doesn't. At that point, you've killed your efficiency, burn too much fuel, and created a source of knock. There'll also be buttload of carbon growing on everything and the cylinder walls will have a nice layer of oil displacing fuel on them. The oil will be nice and black pretty quickly too, with a slight hint of gas station aroma.


Moral of the story, tune for 0 knock (and don't run rich as hell )

 

[Powertechn2]

Yea, thanks.

I understand tuning richer to compensate for higher compression than octane capabilities in n/a engines, I guess that is true in boosted applications. Also know it helps aid in cooling diesels to a point.

I did notice that the retard climbed to the second value after getting hot, not sure what t-stat should be ran in these engine, but I would not think a 195 is anywhere near optimal.

I am planning on changing injectors and chip, from conversation between me and the buddy that had built the car, it seems the chip he had was made for the strip and 110, I will save it I guess and get a proper tune chip for the street that matches the injectors.

He had said he had an issue with ignition breaking up before he parked the car about 10 years ago, I will also work on that first, then work on tuning.
Not sure if I will go tr6 or just factory components for now.
Thanks for the help and explanation of things, including the ratchet strap, it seemed soo hooptie to have a ratchet strap in the engine bay. It has actually degraded over 10 years and isn't tight and won't ratchet, might be some cause for false knock from the mount banging, not sure. Guess a new strap should be there. Never seen a strap in an engine bay before this car, nor after lol.

Also never seen a strap in any pics I have seen.

I can only assume there are better bad ass motor mounts out there??

 

[jhanson1750]

HR parts poly mount on the drivers side and pitch the ratchet strap. Also look if the chip is that old it "probably" doesn't have the street manners of a newer one. I and many others run Turbo Tweak chips which would give you another benefit of being able to just pull some timing in the range your seeing the knock to verify if it's real or false. The 37psi is about right if the vac line is on. Should be @ 43-45 line off. Good luck and happy boosting!

 

[earlbrown]

A $10 Pioneer mount from Advance Auto has held up in the 10's.

Odds are your mounts are original and have delaminated. That could be a source of false knock too. The mount design has a failsafe that has a metal 'hook' that grabs the other side if the rubber should ever become compromised. That makes one hellova 'clunk' when the engine torques over. ESP if it lets downpipes bang into frame components too.

As far as your cooling system, stock thermostats are 180. Odds are at least 2/3rds of your radiator is clogged and only the top 1/4 to 1/3 is actually doing any cooling. It's the nature of the beast when you run horizontal flues. They clog from the bottom up.