Tuning with O2 sensor

[Freddie's Buick]

Rich,

I have Summit's coil and it is very very good! I keep it as an emergancy back-up coil. I used it for about a month then I bought a D.U.I. coil and distributor cap as a combo. The D.U.I. is hotter, (52,000 v), so I stored the Summit coil and installed the D.U.I. one. Any of those after-market coils is an improvement to OEM.

Summit is way cool!

 

[Ttype83]

Originally posted by b4black
If the ignition is the problem, any improvement should help. I went ahead and ordered a coil from Summit. It's there own brand, but it should be an improvement over the stock coil:

It's $35 with free shipping, but a $8 "handling fee".
The MSD stock style coil is $70. The MSD 6 BTM is $335. It's actually cheaper to combine a MSD 6A for $132 and an add-on BTM for $180.

I have the MSD coil...not that I wanted it. My stock one gave out and besides the stock ones at the store they only had the MSD.


Jim, are you racing Staurday? I'm glad you have your problems sorted out. Racing is the best way to tune, IMO. I'd go every weekend if I could. You get can get 18psi? I definately have a problem. 12 is tops for me. I hope this coil does the trick. :fingers crossed:

YES...MY RACING...No problems are not fixed but working on it, narrowed down part of it to a leaking crossover pipe. I'll repull it again tonight and reseal it with cooper. Hopefully it will hold this time.
NO I can not run 18psi....see more below

I'm not sure I follow on the actuators. A leaking actuator shouldn't keep you from building boost - it will stay closed. A blown actuator won't open and will overboost.

If it's opening too early, maybe the spring is week. Try adding an external spring to help it. Most hardware stores have a pretty good selection.

GOOD LUCK!!

OK the stock adjustable style actuator is leaking into the vac side...you can fell the pressure coming out with the car idling. But it still will build boost and is very adjustable (0-15 psi)
The replacement one the I made is to short even when adjusted out all the way. YES the spring on this one feels about half as strong as the stock one. So it will build more boost due to it being to short. I can not handle that much boost with out retarding the timing about 8 deg. Which means I lose on power...it's a no win.

ADD A SPRING How?
Hmmmm If I add a washer to it, I guess I could put a spring inbetween..no that would push it out.

 

[b4black]

I have found that all my (used) actuators leak on the vacuum side. But I have also found that the vacuum side does absolutely nothing on our set ups (the 86/87 actuator doesn even have it). This is a big vacuum leak for the engine however. I have always remove the hose and capped off the nipple on the plenum. So it sounds like your current actuator is OK to me.

If 15 psi is the most it will do, than you can add a spring to hold it closed longer. You need a spring a little shorter than the rod. Hook one end over the WG at the same place where you disconnect the rod (when you make adjustments). Hook the other end to where the acuator mounts to the compressor. It might help to open the loop on the end of the spring. The spring runs (almost) parallel to the rod.

I read about this trick in a magazine. Red Armstrong bought his wife a TR back in 86. He used a door hinge spring to hold the non-adjustable actuator closed to get more boost. I think he bought himself a GN soon after.

 

[Ttype83]

Originally posted by b4black
I have always remove the hose and capped off the nipple on the plenum. So it sounds like your current actuator is OK to me.

That is how I had it setup, plenum pluged and no hose on the vac side of the actuator. If you put your hand over the vac connection you(on mine) will feel the pressure exscaping out. Not out from around the rod. I found it when I was looking for a vac leak and I heard pushing air. I removed it and used a small hand pump and pump in a little air in to the pressure side and it could come right out the vac connection. It still pushes the rod out but will not hold it inplace with out constate pressure. It worries me.

You need a spring a little shorter than the rod. Hook one end over the WG at the same place where you disconnect the rod (when you make adjustments). Hook the other end to where the acuator mounts to the compressor. It might help to open the loop on the end of the spring. The spring runs (almost) parallel to the rod.

OK...If I use a washer locked on the rod..drill a hole in it.....Thanks Rich I got it

 

[b4black]

Originally posted by b4black
If the ignition is the problem, any improvement should help. I went ahead and ordered a coil from Summit. It's there own brand, but it should be an improvement over the stock coil

New coil in, no improvement.

 

[b4black]

The MSD 6 BTM is $335. It's actually cheaper to combine a MSD 6A for $132 and an add-on BTM for $180.

I think I've found an alternative to the MSD 6BTM.

Crane Cams HI-6S for $136 (This is there "budget" Multi-Spark Ignition which should be plenty). To this add a TRC-2 for $118, which is the timing retard control module. It has three modes, one of which is boost proportional when used with the MAP sensor. It turns out to be a lot cheaper and doesn't use two seperate boxes like the MSD 6A w/ the add on BTM. (It also requires a wiring harness, but so does the MSD).

http://www.cranecams.com/ignition/hi6s.htm
http://www.cranecams.com/ignition/hi6sacc.htm
(Prices are from Summit Racing)

 

[b4black]

Originally posted by b4black
The MSD 6 BTM is $335. It's actually cheaper to combine a MSD 6A for $132 and an add-on BTM for $180.

Well, I cracked open my wallet and dusted off the credit credit. I got the MSD 6 BTM. I thought about going the 6A/BTM combo, but finding room for two boxes would be tough.


Easy to install. The $20 wiring harness was a waste of money. I just laid it were the charcaol canniter was for now. I'll mount it better later.

THE STUMBLE IS GONE! The car pulls hard all the way thru 2nd and 3rd. This is been my biggest problem for the last year. I can't wait to see what this does for my ¼ mile times.

Now I just need a bigger downpipe.

 

[Freddie's Buick]

I got a nice spot for the box. (It's were I have mine). Passenger side. Remove the OEM BAR and MAP sensors. Place the box in thier location. Re-locate the sensors around the box. I'll see if I can upload a pic for ya Rich.

Looks so good no one can tell one has an MSD box.

 

[fc227]

I like my 6BTM. I have the timing set to 40° total (No Boost) and has the boost comes in I have it set to retard the timing to 26° at 22#.
It works great. It gives the car more power when not under boost and takes away the timing has boost increases. And it is sorta linear. I have the graph some place I have to find it. But it allows more timing at the lower boost levels so you can tune it to be on the edge of detonation though out the boost curve or play it safe and pull more timing out though the boost curve.

Are you going to use an external coil? If you are the Moroso 72381 is the prefect companion for that.

 

[b4black]

I have an internal Summit racing coil for now. I haven't even hooked up the boost line yet. I'm only getting 12 psi max boost thru the stock air box and stock exhaust. Once the weather gets better, I'll put the cone filter back on. That will get me to 13-14 psi. I think I have a good lead on a place to fabricate a 2½" DP.

I just get some stray knocks here and there, which might be false. Never enough to set the Casper's audible alarm off. I found a place with 100 octane unleaded in town, so I'll get a chance to confirm if it's flase or not.

I have an appointment with a Chassis Dyno this weekend. (Chicagoland GSCA)

Freddie, that's a good idea. I'll have to see if I can relocate the MAP and ESC controller. Or maybe get a smaller coolant bottle.

We had snow here last night. Outta be hitting the east coast right about now.

 

[Freddie's Buick]

I did'nt have to remove or re-locate the coolant bottle, that's the beauty of it!

Since the fender skirts are plastic, re-locating and re-attaching the sensors around the MSD box is easy. Image pending.....

 

[Freddie's Buick]

O.K. Rich.....

Let's see if this works....

http://home.earthlink.net/~familia.diaz/images/MSD 1
http://home.earthlink.net/~familia.diaz/images/MSD 2

 

[b4black]

Originally posted by b4black
The stumble was still there, ......

I had the DMM connected to the O2 sensor and saw someting I don't see on the street. The O2 reading were all over the place going thru the traps. Rich-lean-rich-lean. I think what's going on is misfiring under high rpm/high boost causing erratic oxygen levels.

....I what to buy a MSD 6AL BTM, but they are expensive

I put the DMM back on the O2 sensor today. As I expected, since the stumble is gone, the erractic WOT readings are gone as well.

The weak ignition must not have been igniting the air/fuel charge. The oxygen levels were going back and forth from low (high mV-rich) to high (low mV - unconsumed oxygen).


For the first time, I can say the car is running very well. Now to get some more boost.

 

[Freddie's Buick]

So what's the verdict on MSD Rich?

 

[fc227]

What plug gap are you running?

 

[b4black]

Did so "test n tune" today.

1. Put the K&N cone on and went for a ride. THE STUMBLE CAME BACK!
2. Took the cone off. Still stumbled some.
3. Last year I had speculated it might be too much CFM from the carb. It seemed to stumble worse with the secondary air valve tab bent (allowing the valves to open further). So to confrim this, I bent the tab again to see if the stumble got worse. I also clamped the wastegate shut (it was set at 12, the best I could get out of it last year before it fell on it's face). Went for a ride, just a little stumbling, but 15 psi!
4. did some more runs bending the tab back and forth. No correlation with where the tab is and the stumbling. It's always there, but not as bad as before. Last year at 12 psi, it would about shut down. I was able even to get up to 18 psi without setting off the knock alert.


So the MSD definately helps (a lot), but it hasn't cured it 100%. Still, I give it a thumbs up!


The plugs are AC/Delco R44TS plugs; 0.035 gap. That's the tightest I have gone. I've tried a heat range colder before, but no difference. Maybe I need to go 0.030???

 

[fc227]

You could try going down to .030" . But what shape or the cap & rotor in and the wires?

This "stumble" is it only at WOT? Or is it off idle? , Is it above a curtain boost level? When I had too much carb the car fell on it faced a stumbled like there was 3 plug wires off.


Just my opinion.

 

[Freddie's Buick]

Yous guys got me confused.....

Why are you running cold plugs with short gaps?

The HEI systems were made for wider gaps.

The OEM HEI spark is huge.....that is why a wider gap is required. (.080 on mine, R45TS8 or it's modern equivelant R45TSX).

Are the Turbo cars that differant?

 

[fc227]

True, A HEI system provides a hot spark, but under the higher boost conditions it will require more voltage to fire that gap. Also when you run a wide gap on the spark plugs it makes the rotor & cap live shorter because of the increased load of the wide plug gap.

I run a MSD6btm with a Moroso 72381 coil, that baby produces up to 80,000 volts. I used to run a .050 plug gap. Didn’t have a problem with a miss even at 22# of boost, but I was replacing the cap & rotor every 3 months because I burned the tip off the rotor. I am not running a HEI dist. I have a Moroso Billet dist.

 

[b4black]

Originally posted by fc227
You could try going down to .030" . But what shape or the cap & rotor in and the wires?

This "stumble" is it only at WOT? Or is it off idle? , Is it above a curtain boost level? When I had too much carb the car fell on it faced a stumbled like there was 3 plug wires off.


Just my opinion.

The cap and rotor are original. I just bought a Wells premium cap and rotor. I don't know how good they are, but they are a step above the el cheapo caps. The wires are newer, but 8mm. I have some new, better quality (8.5mm?) wires on the shlef I can try. Seeing how the MSD helped, I think I just need to get the rest of the ignition up to par for 15 psi of boost.

The stumble comes on as soon as I hit second gear. It's not rpm or boost dependent. I know of a electronic Quadrajet "expect" in my area that I can call if the cap/rotor/wires don't help.