Timing question.

[phoenix64]

I'm curious now because of what GN and teufel said about the stock timing. What is everyone running as far as timing on boost?

I don't mean to sound like I don't beleive your results, I'm more curious what I'm doing wrong.

GTP's run less timing than we do, even with less compression, and I remeber that guy that documented the whole history of his powerdyne setup years back, he picked up 10-12 hp by dropping timing on 6psi of boost. I know neither of those are intercooled, and you never know what A/F they were running, but what am I missing?

[CM boyd]

Well, before the turbo I was running 6 degress of
advance timing with Bosch platinm-4s,93 octane, ignition booster, performance coils, wires, and fuel trim set at 14%. It was good for about another 10 hp at the wheels.

I have the same mods and set the retard to 8 degrees.
It is running smoothly. I don't trust the stock tune when it comes to timing because to my knowledge the CPU is not designed to retard timing that much over 5psi. The CPU in the l67
engine can. Even Corky Bell's book
"Maximum Boost" tells that ignition retard is best used as a safety measure. Less timing is less power. What are you using (if anything) to
adjust timing? How much boost?

[1DangerousV6]

i am in no way recommending this..but when i had my 6 psi powerdyne on i didnt even have the boost timing module installed..just the kit and the FMU..just always ran 92+ octane fuel..obviously this is not an option for higher boost levels

[nocutt]

GTP's run less timing than we do, even with less compression, and I remeber that guy that documented the whole history of his powerdyne setup years back, he picked up 10-12 hp by dropping timing on 6psi of boost. I know neither of those are intercooled, and you never know what A/F they were running, but what am I missing?

You cannot talk about timing, without talking fuel octane...they all go in tandem...
The reality is the ability to map timing and fuel together is possible, just some work. The other way is to pull timing from the total commanded. I will not really stress over it if you aren't running that much psi, just use more octane like already suggested! On the other hand, when playing in big boy territory then a fuel and timing curve will need to be mapped together!

[phoenix64]

I'm using hptuners, 11-12psi, 92 octane. I also assumed that teufel was using pump gas, but it would explian a lot if he wasn't.

I still would like to hear from Teufel, and GN BTW, as to how Teufel is running stock timing, and seeing no retard.

I'm mapping the KR and then using those tables to pull timing from the tables. A/F is in the mid to high 11's under boost.

I wonder if the knock is even ignition related.

I can get away with full timing when the engine is just getting up to temp, but once its been run for awhile, it starts picking up knock. I read an article about porsches, which run the exact same compression as our 3.8's, along with 15psi of boost, they do it by extreemly precise cooling of the heads, to make sure there are no hot spots.

[nocutt]

Yes it gets very complicated...2 cars with the same mods, but because one cools better can make a lot of difference with knock.
I think in terms of knock many ppl DO NOT understand how they apply to the 3800II. The information is almost generic from a vehicles perspective, however this computers tell a different story. Teufel might be using volume of fuel...at least at the particular dynamic compression he is running...it is still safe. By adding fuel indiscriminately under boost, the extra fuel will help curb KR to a point at least!
Also another thing to consider...if the knock module is overly sensitive as is the case for most L36's running a lot of power, you occassionally find false knock. Some folks are lucky, some aren't...ultimately it can be tuned out...you just have to get into the yen zone ;)

Personally, if you are a daily driver pull timing, not too much as to start creating more heat. It will help in the long run, in regards to longevity...if you don't care then map more fuel(vol)for the cells with more kr then perhaps use octane to knock the rest off. The problem with trying to map timing is the event itself has not happened and every event is different...

[GN-T66]

two things to consider... on TF's car, the intercooler is huge. 24x12x3, and has outstanding airflow, because it is mounted at the correct angle in the nose for optimum airflow (angled back some), and is essentially ducted as well. Using a pyrometer, the intake pipe right up onto the throttle body is almost ambient in temperature. I was shocked the first time I felt how cold it was. even the clamps holding it on to the TB were cool, no heat in them at all. this gives you an idea of how well it cools the intake charge,

And also, the car does have the fuel. the FMU is working pretty hard in that car. the air fuel is very good according to the wideband in the y-pipe. there's probably 5-10hp left in the car running it a bit leaner, but the margin of safety is worth it.

[phoenix64]

When you say the fuel is very good, are we talking 10:1 A/F?

Even with intake temps in the 10-20 range I still have knock, at least when the engine is warm. Like I said, with a cool engine the knock magicaly dissapears.

[nocutt]

Originally posted by phoenix64:
When you say the fuel is very good, are we talking 10:1 A/F?

Even with intake temps in the 10-20 range I still have knock, at least when the engine is warm. Like I said, with a cool engine the knock magicaly dissapears.

GN...I will agree that the IC is doing its job, but that is just one angle that helps...I can guarantee, if the IC ever gets heat soaked the situation will be different. A good example, will be a nice jaunt on a road course...
regardless it is a big IC :D

Phoenix, couple of questions? where is your IAT located? Also have you ran the motor at lesser psi? if you did, was there KR? And does the KR increase with load...how high?

[phoenix64]

The IAT is 3in before the TB. I have run the same PSI the whole time. Yes the KR will increase with load. Knock is worst at low RPM High load, even with negative timing, the sensors will pick up knock.

Like I said, this is with an engine that has been run for a while, the knock goes away if its just getting up to temps.

Also I realize that Teufels IC is huge, but my intake temps are 15-20* under full boost. Your telling me that that will make a difference?

I'm sorry, but I'm calling BS. Our engines are not well enough designed to get OVER 10psi, on pup gas, and see no knock retard. That would be like having a static compression ratio of 14:1.

[Turbo Kyle]

How much Total Timing are you guys running under boost? 15? 20? 25?

[phoenix64]

At what RPM?

[nocutt]

phoenix64,
I feel you...but you cannot call BS if you haven't seen his scan logs and 10psi on this engines isn't even close to 14:1. (T-H isn't @ sea-level...think about it).It is possible to run 10psi without seeing KR...we do it without IC's on 3800 fieros. The trick is tunning...I think you should drop down your pressure and run more octane and see what happens. In my case what I did was tuned the car (this is why I tell ppl electronic boost controlling is literally your friend) by 3psi. eg 3psi...tune...drive, another 3psi...tune, drive another 3psi tune. I stopped at 12psi!! NO knock...with 91 piss-owl octane. My setup is different from yours like night and day...I am using stock injectors and two auxillary 36lbers. The black box I am using controls this injectors, retard timing and it is also an e-bst controller. Anyways, I removed timing were there is more load...like mid RPMs...this is per 500RPMs (like cells) and then add back enough timing at the top. I am going to be getting rid of this setup soon and move into the '05. My setup is archaic...lol! I don't know if HP tuners have the ability to play with the KR tables...eg attack rates and decay rates!?!?

[ January 21, 2005, 09:38 PM: Message edited by: nocutt ]

[phoenix64]

Sorry about that I retract the BS, I forgot he's not at sea level.

When you say run more octane you mean race gas?

Yeah you can change the attack rates for KR, but I haven't gotten into that.

So are you saying that the KR is false? I don't get it. You keep saying you have to tune it better, but other than making even richer what can I do?

[nocutt]

Yes run more octane...maybe around 93-96 or just get some race gas...see what happens, if you still have KR same rate, then rest assured it is false knock, something might be loose hitting the block or the sensor is picking up background noise. It is common when making substantial HP...I don't know how they were programmed from the factory, in most cases when we use the aftermarket PCM (haltech) on the 3800s we delete the knock parameter. So in theory you don't really need it if you are 100% on your tune. The knock sensor is a fall back, which is pretty good if one is new to tunning.
Running the engine a little bit richer is safer to a point. You can still get rich induced misfires...my point is try to design a fuel curve with timing and boost. This will provide an almost 3 dimensional "feel"...Just do it one variable at a time till you are comfortable...so run the engine at a lower boost pressure with higher octane and all your available timing. Increase boost 2psi at a time, see what the car does..You know you can make more power running less boost and all your timing than running more boost with less timing on the account that the PCM is pulling it...