I was playing with timing today and I think I'm getting best results
at 14 BTDC.
Isn't this too high?
I read somewhere that stock it should be @6 BTDC.
I've tried with 6 BTDC but it's definitly not good.
The scale is only to 12 BTDC but it feels to me that it's best when
timing is set of scale @ 14 BTDC.
What do You think?

 

Can you say knock? A guy just came to my home this past weekend that wanted his car tuned. He had his timing cranked up to 9* and I expressed to him that he had to be getting all kinds of knock retard. Slowing him down ultimately. He said everything felt good.

He showed up and before we even got out of my driveway he had 6-10 knock counts! When he was driving it was just FULL of counts. It felt like we were towing a boat behind us. We put his timing back to 6* and started tuning from there.

The car is much, much better now. No more boat. You can not tune a car by just adding time. As I stated before, it may feel better, but your butt meter is not a good tuning tool. By the time the guy left this weekend he was very happy with his car and has called me the past two nights thanking me. I'm sure if he reads this he will pipe in.

All in all, you can not efficiently add timing via the distributer. WHat you are doing is increasing SA in all area of the table. So you may be helping some areas, and killing yourself in others.

Others will say they have done it and it worked. But there is a right way to do it and that is with a scanner and new chips.




[Modified by ski_dwn_it, 3:28 PM 6/25/2002]

 

The harmonic balancer might have spun a little. Mine did on my 86.

 

did you have the 'advance' wire disconnected?

 

I'm not sure what do you mean by "advance" wire, but I didn't
disconnect anything.

When I put it to 6 BTDC it feels like I'm towing the house, not boat.
It's missfiring and there is a lot of poping from exhaust.

Now on 14 BTDC it really feels strong, especially on low rpm's
and it maybe feels a little worse past 4000 rpm's but I can't
tell for sure.

One thing is sure. It's almost impossible to start without wheel
spinning, and when I tried with timing @10 BTDC it could barely
spin the wheels even with powerbraking.

 

There is a connector to the inboard side of the brake booster that needs to be disconnected in order to set the base timing.

 

Yeah...It sounds like you have been messing with the timing without first unhooking the wire next to the brake boost.

That wire gives you the ECM advancement. You should unhook the wire and set it at 6*. Plug the wire in and all will be right.

Sorry. I the first post I thought you were purposely setting the base timing at 14*. Well I guess you were, but not really.

 

I ran my 86 at 10 degrees with no ill efects. As long as I ran premium there was no pinging.

 

I agree that altering the tables in the prom (or whatever) is best. It is the distributor recurve of today. However, not being blessed with the tools and instrument to do that I have experimented with my initial timing. Currently, and for the past two years, I am running 14* initial advance, set properly, with the EST disconnected, when setting the timing. My peformance meters are the clocks at the strip. For the timing, I pay the most attention to the MPH. MPH is the best indicater of overall HP. I have NO knock counts. If you don't have a dyno and/or re-programming facilities, this is better than nothing. Good luck.

 

Sliding, sounds like you and me were in the same boat. I to would play around with timing looking for that sweet spot, and I found it between 8 and 10. The only problem is that the next day it felt like I was dragging something again. I posted questions like this and the replies all pointed to custom tuning. I realized that I didn't have the knowledge to do this myself, so luckily "ski_dwn _it" did me a huge favor and spent all day tuning it with the laptop. The car runs perfect now. Strong from start to finish with no slow spots. It was a 4 1/2 hr drive up and another 4 1/2 hr trip back, plus a night in a hotel...and well worth it. Before the custom chip I could barely spin wheels even with the 3.73's, and now I can break them at 15 - 20 mph, and I'm getting solid chirps out of my shift kit. Bottom line is that if your serious, tune it with a laptop. If you're like me and lack the knowlege, try to find someone that can. After seeing my tuning scans, I can't imagine your not getting knock. Like "ski_dwn_it" said, I had knock before I made it out of the driveway. Good Luck.

 

I have the same problem always - I live in Croatia, and here you can
count Corvettes on fingers of one hand. Nobody knows a lot about this cars
so I prefer to do everything myself.

I'm planing to get a scan tool and tuner cat software but not just yet
(financial issue). Until then I have to do everything with butt-meter.

 

Is this wire connected to distributor?
How does connector look, I don't want to disconnect something wrong.

 

The connector is black it's self. it is a 1 wire connector. I believe the wire is tan with a black stripe???? I cant remember, I wired mine up to a switch.

BTW, when you disconnect this, and set your timming. Then reconnect. When you get in your car, you will probably have your check engine light on. This code is telling you there is an opening in the (ESC???) circut. Disconnect the negative battery terminal after you set the timming, for about 1 min to clear that code, and go drive it about to see how it is.

On a side note, when I put my new motor in, it liked 14 degrees. after getting it running better I backed it off and now run about 10.


[Modified by bill mcdonald, 1:48 AM 6/26/2002]

 

O.K. Thanks!

:chevy

I'll be back with results.


[Modified by Sliding, 1:33 PM 6/26/2002]

 

I've tried with disconnected "advance wire" yesterday.
Guess what?
14 BTDC with connected wire = 6 BTDC with disconnected wire
I guess my but-meter is very accurate! :D