Comparing stock spark advance tables...

[turbokinetic]

Hey guys I am tuning a turbo system on an (originally) naturally-aspirated car. It has a 7783 ECM that is MAF-based.

Could someone point me to a STOCK main spark table for an intercooled GN?

I want to compare this to my spark table in the N/A calibration.

Don't want anyone's proprietary table - just a stocker for comparison.

I have rescaled the constants to allow the LV8 to not max out and need a starting point for a spark table.

Thanks in advance,
David

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Here is my project. I have less than $1000 in the whole project including the car and used turbo:

 

[mikestertwo]

I can PM you one if you like. Stock BBKJ spark table.

 

[turbokinetic]

I can PM you one if you like. Stock BBKJ spark table.

That would be wonderful! Many thanks!
David

 

[pacecarta]

or just go here
Chips, Scantools, and EPROMs

 

[mikestertwo]

Spark table sent to your email

 

[pacecarta]

heres a more friendly table for todays 93 octane

 

[turbokinetic]

heres a more friendly table for todays 93 octane

Awesome - thanks!
David

 

[pacecarta]

heres the timing map for the BBKJ recall chip for the 87 Gn

 

[turbokinetic]

Spark table sent to your email

Thank you sir! As I tuned today - I ended up manipulating mine so that it is already getting close to this, at least at the high LV8 regions.

Sincerely,
David

Ps - I did have a good 'kill' today of a very new silver BMW 535I. It was driven by a 30something male with dark shades and a bad attitude. He was following RIGHT on my bumper on an Interstate ramp that was a long gentle curve. We were going faster than the suggested ramp speed already - and there was a car ahead of me.

When the road opened up, he started to gun it around us in the "white hash mark area" before the ramp was open.

When the lane fully opened - I politely signalled, passed the car I was behind on the ramp, and opened up the 3.8 turbo! Quickly I reeled in the Bimmer like a fish on a string - blew around and left him back there wondering what happened! :biggrin:

Later in traffic when he caught back up - he looked pretty ill about it!

David

 

[pacecarta]

keep in mind that table is for 93 octane and an intercooler at up to 255gmsec (approx 15-17psi)

you should be ok with the revised table i posted but its up to you to find out what your car will tolerate without knocking

 

[turbokinetic]

I have 2 goals here. First one I already accomplished. I learned what can be done with all the stock LG3 3.8's engine management system. Several members of the A-Body (front wheel drive) car club talk about turbocharging their cars and wonder what can be done to a "bone stock untuned" engine. With this LG3 untuned I was able to push 5 PSI boost without detonation. The LV8 was maxxed out.

Then with rescaling the LV8 I made room to control the timing under boost with nothing maxxed out. Next limitation of the stock setup was the 17.5 Lb/Hr injectors. They supported about 7-8 PSI before I could not hold 11:1 AFR. I installed some 28 Lb/Hr injectors from a Supercharged 3800 and have plenty of fuel now. I'm running 10 PSI and seeing LV8's in the 210 to 220 region. I think the next limitation will likely be the mass airflow meter maxxing out. This has a similar (but smaller) MAF than the LC2 has.

It's already far stronger than what the 440T4 transmission wants! My second goal is to make 240 flywheel HP, since this is what a stock 3800 supercharged engine has. This car has the LG3 factory roller-cam front-wheel-drive 3.8 SFI that is nearly identical to the LC2. I can only estimate the flywheel HP based on drivewheel HP on a chassis dyno. I calculated that the engine should do it at 10 PSI, since it made 150 HP natural aspirated.
It's there at 10 PSI now and I am just trying to get the spark dialed in. I've got a wideband datalogger that datalogs and displays detonation for a tuning aid.

Bear in mind I have only about $1000 in the car - including the turbo conversion and buying the low-milage 87 Century Limited. (However - not counting the repairs to the engine due to the broken timing chain.)

When it gets its turn on the dyno - I will take videos and post them here for sure!

Thanks again for the help!
David

 

[Mad_Trbo]

MAP _ Timing

heres the timing map for the BBKJ recall chip for the 87 Gn

The body of the chart holds final timing numbers correct?

Additionally along the top row is that KPA, I've been looking for something like this to get a ball park on stock timing.

 

[mikestertwo]

Additionally along the top row is that KPA, I've been looking for something like this to get a ball park on stock timing.

The numbers along the top is the LV8 numbers (engine load)

 

[Mad_Trbo]

Engine Load LV8

Great I figured it was load, now for the hard question is there a conversion to PSI or KPA?


Thanks

 

[mikestertwo]

Great I figured it was load, now for the hard question is there a conversion to PSI or KPA?
Thanks

No conversion. The load numbers (LV8) are calculated based on MAF readings, throttle position, and RPM. The computer has no idea what the actual manifold pressure is.

 

[pacecarta]

stock boost was about 14psi at 3rd gear

if your looking for a timing chart based on kpa , download c-com WP for FAST on Fuel Air Spark Technology? - The Leading Name in Fuel Injection - EZ-EFI®, XFI?, Air Fuel Meters, Distributors, Alternators, Fuel Injectors, Intake Manifolds, Big Mouth 92mm Throttle Bodies? (goto downloads)
once you're loaded up run c-com WP and then goto read files and open one of the demo file (gct), its for a buick stage motor

depending on the motor and fuel used , i/c capabilities etc the timing you can run under boost should be adjusted accordingly

 

[imaboa]

heres the timing map for the BBKJ recall chip for the 87 Gn

Mind if I interject and ask a quick question?

I'm doing my reading before attempting to tune the stock ECU in my dads GN, I noticed that the spark table only goes up to 4800 rpm, although in the particular file ive been working with the rev limiter is set to 5700.

Where does the ECU look for that other 1000rpm worth of spark values?

 

[ijames]

Might find this thread interesting: http://www.turbobuick.com/forums/computer-chips-101/52885-what-really-lv8.html?referrerid=908

 

[pacecarta]

the timing would continue as it was at 4800 @ 21.15 , fueling increase stops as well which is why you need a modern chip if you plan to play

easier way and less time consuming and safest to tune your dads gn is not to play and go to TurboTweak Home and get a chip

 

[imaboa]

Playing is fun

When you say a 'modern chip', what do you mean exactly?

I suppose if the timing is locked in at X* after 4800rpm, and the same with fuel, thats probably ok since the VE of the motor falls off as well. Providing the boost doesn't creep up substanitally in the last 1000rpms.

Is there a way to re-scale the RPM axis lke you would for the load values?