soundkillr

Hey, I have a 91 l98 6 speed with the following mods, adj fpr set at 43 psi, k@n open lid, ported intake, 24 pound injectors, ED Wright stage 2 chip, high flow cat, and borla exhaust, pulleys, and 160 thermostat. I am looking at bumping up my timing. Here is the question, does the chip effect timing at all? What should stock timing be, and what do you recommend bumping it to? The car only sees 93 octane. Also could someone give the procedures for doing it? I have never adjusted timing on this car, and as far as I know its stock. :confused:

soundkillr

???

scorp508

Stock timing is 6* BTDC. I ran my engine as high as 9* without issues before. L98Terror I have seen run 12* without issue before. Every car is different, it just takes some trial & error to see what it likes. :)

On my own car when it was stock I gained 1.5 mph in the 1/4 mile going from 6* to 9*. I never got a chance to try higher that night.

scorp508

Procedure...

..with the car off disconnect the EST wire. It is a single brown wire near your brake booster. A single connection.

Loosen the distributor bolt slightly (9/16" bolt) and start the car. With a timing light set your timing. The timing tab is on the timing chain cover. You have to kind of look through the AIR pump bracket to see it. Turning the distributor cap counter-clockwise I think is adding * BTDC (brain fart).

Once you have it set tighten down the bolt and recheck your timing with a timing light to make sure you didn't move it. Shut the car off and reconnect that EST wire. Then start the car and try it out.

soundkillr

Thanks Scorp! BTW The chip doesnt effect timing does it?

scorp508

Your computer controls the amount of timing it can pull out, but has no control over the base timing which you are setting here.

0ski_dwn_it

This is my opinion and I think its fairly on track.....

To just add timing without any reasonable way of telling if you are inducing knock is just silly. To make the assumption that just adding timing picked you up X amount of time can be actually the result of many things. ie. Temp, humidity, etc.

I would bet that in nearly every case of where timing is just added at the distributer, there are knock counts added as well.

Now for ETs that may actually help, here is one instance. If your car is running very strong, say spinning badly off the line. When the timing is added it could induce some knock and actually decrease that spin ultimately turning a better time. Then the person walks away with the thought that they were not running enough timing, when in fact if they had the proper traction they would have seen the results and then some.

Again this is my thoery, but GM has spent tons of money researching and developing the timing tables. If you want to generic them up by adding universal timing to the whole thing. I guess that is your perogitive.

I don't mean to be harsh, but I think you deserve the right to hear the downside of taking shortcuts. And adding timing via the distributer for anything more than experiment, of one area of the map, is just that.




[Modified by ski_dwn_it, 6:56 PM 6/29/2002]

scorp508

GM also has to deal with emissions and making a car likeable to all buyers. We don't. Another thing about timeing is the less BTDC you go, the more bottom end power it adds while sacrificing a little top end. The more BTDC you go, the less top end and the more top end.

I have played with the timing in the course of a night at the track and it can and does help to find the sweet spot knock count sensing or not. Computers are only as smart as you tell them to be.

0ski_dwn_it

Yeah and you are lying to yours. If you talk to any tuner, they will tell you that the base ARAP timing map has WAY too much timing to begin with. I almost every case you will need to pull timing to get the car running correctly. Not to say you can't get one condition correct by adding timing at the distributer. For instance WOT, but I will be a million dollars your throttle response at cruise will suck. Or your bottom end will blow and top end will feel good.

Once you get to tuning your setup, Scorp, you will realize what I am trying to say. Ask 88 triple black if his car runs any better. He was doing the same thing to his and he swore it would not make that much of a difference above his method.

When you look at the timing map of the ARAP chip it becomes very obvious take a looksie.

20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
20.0 20.0 29.9 29.9 29.9 29.9 27.1 26.0 23.9 20.0 20.0 20.0
20.0 29.9 40.1 38.0 35.9 34.1 34.1 28.1 26.0 23.9 20.0 20.0
29.9 34.8 40.1 40.1 40.1 38.0 35.9 32.0 29.9 26.0 22.1 20.0
41.1 41.1 41.1 41.1 40.1 39.0 38.0 35.2 34.1 28.1 22.9 21.1
43.9 43.9 43.9 43.9 41.8 41.1 38.0 34.1 32.0 28.8 25.0 23.9
46.1 46.1 46.1 46.1 46.1 43.9 41.1 41.1 39.0 28.8 25.0 23.9
48.2 48.2 48.2 47.1 46.1 45.0 43.9 41.1 38.0 30.9 28.1 26.0
48.2 48.2 48.2 47.1 47.1 46.1 43.9 41.8 36.9 30.9 28.1 27.1
48.2 48.2 48.2 47.1 47.1 46.1 43.9 41.1 35.9 30.9 27.1 25.0
48.2 48.2 48.2 47.1 47.1 43.9 43.9 38.0 29.9 27.1 25.0 22.9
47.1 47.1 47.1 46.1 41.8 41.1 38.0 30.9 26.0 22.9 22.9 22.9
47.1 47.1 47.1 45.0 40.1 39.0 38.0 30.9 26.0 23.9 23.9 29
47.1 47.1 47.1 45.0 40.1 39.0 38.0 30.9 27.1 27.1 27.1 27.1
47.1 47.1 47.1 45.0 40.1 39.0 38.0 33.0 33.0 33.0 33.0 30.9
47.1 47.1 47.1 45.0 40.1 39.0 38.0 35.2 35.2 35.2 35.2 35.2

When you figure at WOT it adds another 9 degrees of advance at WOT for 3200 RPM! Plus your 3-5* across the boards. Comeon we are not running big blocks with 120 octane gas or 350-406s with pump gas? Besides that there is only 45* of seperation on the distributer post and that much timing would induce cross firing. But GM must have suspected such activities and worked in a ceiling advance in most of the bins.

As I stated before, there are many ways of doing things, then there is the right way.

You decide what is best.

Triple Black 88

Hey soundkillr, about 2 months ago I got a 3.73 rear, complete tune up, new trans, dual exhaust, Borlas, etc... The car felt better, but it wasn't what I expected. It was lacking torque, had soft spots and it felt like I was dragging something. I posted questions about it and replies said to check the basics, one being the timing. The mechanic assured me that he set it after the tune up, but I decided to check it anyway. It was at -1BTDC :eek: . So I bumped it up to 6 and WOW, what a difference. Then I got curious. What would it feel like at 8,9,10??? I played around with that and the TPS for over a month looking for that sweet spot. It seemed like everytime I adjusted it, it would feel good for a day, but then that feeling would go away the next day.
So I posted a question about that and most of the replies pointed towards tuning with a Laptop. I have no idea how to do it, so I asked "ski_dwn_it", on of the guys who replied, if he could help me out. He agreed (Thanks Again Jesse) and I made the 4 1/2 hr trip to his house. He noticed that I had major knock, even before I made it out of his driveway. I had a Hypertech chip and the timing was at 8* or 9*. To keep a long story short, he tuned it for about 6 -7 hours until he eliminated the knock, along with a lot of other things. (something about BLM's ). The car feels 100% better. No drag feeling, infact when I hit the gas it feels like someone is pushing me down hill. It feels strong and smooth, and the timing's back to 6* and the TPS is back to .57. I get solid chirps and flawless throttle response. I can even break the wheels at 15mph :yesnod: !!! I don't pretend to know anything about tuning, but I am definitly a believer. I can almost guarentee that you are getting knock counts (which are slowing you down) all through the RPM range with that cookie cutter chip. Its like giving everyone who wears glasses the same pair. I believe cars are the same way. Get your car tuned right and you'll see what I mean.
Scorp said that his MPH increased after adjusting his timing, and I believe it. Like I said, mine felt great when I adjusted it, but the real test would be to leave and go back another day under the same conditions, and make another run. I don't think you'd see the same results. That was my biggest problem. I kept thinking, if I it would just stay like this. Well with the new chip, it does stay like that.
Let us know how you make out. I'd be curious to see if yours reacts like mine.

soundkillr

Interesting you bring this story up. I have complained to others that some day the car runs like an animal, and other days, doesnt run so well. I cant figure out what it is but.....
So what I have gathered, is perhaps before I adjust base timing, I should get someone who really knows about these cars, with the laptop software, and go from there? I would also suspect I am getting knock from somewhere... :confused:

0ski_dwn_it

What you are doing is messing with the BLMs when you adjust the timing. Until it learns and makes adjustments your car *may* run/feel stronger. Then back to the old after it does.

Get ahold of me via email if you like and maybe I can help.




[Modified by ski_dwn_it, 10:58 AM 6/30/2002]