ESC Tech

[CTX-SLPR]

Howdy,

I just got the 95% answer to my question on the use of the 7-pin HEI with a megasquirt on my planned LSR car. The answer is "stock equipment sensor controlled ignitions may be used but may not be modified in any way from stock." As such I'm now left to wonder what I can do with a factory ESC system (or if I can find one) or should I be looking to convert to an aftermarket distributor based (potentially with a MSD box type addon) system.

How capable is the stock ESC system for an 81 Turbo6? What kind of upgrades exist to parts like the module? Doesn't sound like I can reprogram it but is such a thing possible? How tollerant is it about the feedback style carb being missing? At what HP does it become a bottleneck?

Thanks,

 

[b4black]

The factory ESC runs thru the ECM on 1981 and later engines. The megasquirt replaces the ECM I presume. Sounds like a problem unless the megasquirt support knock sensors.

The 1981 and 1982 uses a ECM and the old style knock sensor (accelerometer). In 1983 they went to the peizo sensor like the SFI engines use. I assume the peizo has an advantage over the accelerometer. It's certainly a lot cheaper. If megasquirt supports knock sensor, then a sensor & module from a 1983+ should be all you needs.

If not, you can still use a 1983+ knock sensor and module with a Casper's knock gauge. It won't retard timing, but it will give you a visual on what's happening.

 

[b4black]

Try this:
http://www.megamanual.com/ms2/knock.htm

 

[CTX-SLPR]

I think you missunderstood me. I can't use the Megasquirt like I had hoped, I have to use either the factory ESC (I might be able to argue using an 80 unit but worst case the 81) or convert over to something else.

How big of a bottleneck is the factory ESC and if I'm not terribly worried about knock on 110 octane gas, how much does it give over a conventional vacuum distributor? How upgradable are the various components other than reprogramming the ECM or equivilent for earlier units?

Thanks,

 

[b4black]

Yep, sorry, I misunderstood.

I haven't used a a vacuum disturbutor on a carb/turbo, so I guess I'm not too much of a help.

Basically there are three factory setups:

1. The stand alone ESC controllers with vacuum HEI distributor and accelerometer. 1978-1980
2. The ECM-ESC controlled HEI distributor with accelerometer. 1981-1982
3. The ECM-ESC controlled HEI distributor with piezo sensor 1983

I would assume the systems improved with each year and that the 1983 is the best.

This might help:
http://www.beforeblack.net/knock.htm

 

[CTX-SLPR]

Do you know if you can jumper out the solenoid or whatever runs the feedback on the Q-jet? I would imagine that the rest of the system is going to be fine if it gets TPS and the rest of the signals from sensors, just have to convince it to run "normally" without the carb stuff hooked up.

I'm guessing the 81 system will pull timing for knock, high coolant temp, and maybe more factors? Going to read up on your link, have anyother links to stuff on the B4B electronics?

Thanks,

 

[b4black]

I follow what you are trying to do, but I've never tried it myself and don't know if anyone else has successfully. I don't know how sophisticated these ECM's are, but they are the earliest system and pretty basic. Nobody started decoding the ECM until the SFI cars came out, so there isn't much understanding of the feedback carb systems (the Chevy guys just yank the ECM and emissions 'junk'.)

I don't think the ESC takes anything but knock into consideration for timing retard. The ECM could adjust timing when there is a check engine light fault (but I suspect not). If it does, you should be able to get around the MC solenoid with a jumper or resistor. You would need to do the same with the O2 Sensor.

I'm hoping what you are trying works. It would be great to keep the factory ESC alive while using different carbs.

 

[dr_frankenstein]

The factory ESC is great and can be used in a stand alone configuration with an aftermarket carb if your going the route its very very effective.

but there is one major hurdle to overcome if you plan on using the factory system. This is the reason i went away from the ESC myself. its the 5 pin HEI module. it wont turn much past 5800 RPM. will induce bad spark scatter much after that with high boost 20lbs+

 

[charlief1]

The factory ESC is great and can be used in a stand alone configuration with an aftermarket carb if your going the route its very very effective.

but there is one major hurdle to overcome if you plan on using the factory system. This is the reason i went away from the ESC myself. its the 5 pin HEI module. it wont turn much past 5800 RPM. will induce bad spark scatter much after that with high boost 20lbs+

Well what about above 20 PSI and below 5800 Aj?

 

[dr_frankenstein]

Well what about above 20 PSI and below 5800 Aj?

well lower RPM would be better, but increased boost does little for it. the 5pin HEI module simply cannot support the needed amount of amps to fire either high boost or high RPM. its just electronically limited as this was never designed to be a high performance part. they was never any intention to cross the 11psi or 6000rpm mark. Thus, why you see the high performance modules for the 4 and 7 pin hei modules.... for hiher RPM and amp capabilities

 

[CTX-SLPR]

Well that's semi promising as I'm trying to limit the car to 6000rpm and probably going to be running compression in the 9+ range since th good gas is available. Th will probably keep the boost down but I'm not sure if enough to keep it in the range of the stock system.

I wonder if a 7-pin could be retrofitted to work with the ECM...

 

[dr_frankenstein]

Well that's semi promising as I'm trying to limit the car to 6000rpm and probably going to be running compression in the 9+ range since th good gas is available. Th will probably keep the boost down but I'm not sure if enough to keep it in the range of the stock system.

I wonder if a 7-pin could be retrofitted to work with the ECM...

So are you going to be using the electronic carb? im confused by alot of this.

is this why you want the mega squirt?

 

[CTX-SLPR]

No Megasquirt, no electronic carb.

Just a blow through carb and trying to see if it's worth trying to use the stock ESC system since it's allowed per the rules but with no changes. Give the choice, I'd use a megasquirt with a 7-pin HEI but that's not allowed.

 

[dr_frankenstein]

agh i gotcha.......... well i do have 1 early stock style ESC system... if your interested.

yea its a hard fight anyway up from there....

 

[CTX-SLPR]

agh i gotcha.......... well i do have 1 early stock style ESC system... if your interested.

yea its a hard fight anyway up from there....

Don't know if the rules will be hugely picky but just incase, what year is it from?

Thanks,

 

[dr_frankenstein]

i believe it is an 80..... but i would really really be hard pressed for a non B4B, non buick person to tell the difference.... i can barely tell the difference if it wasnt for the length of the lead and the color of the plug other then the fact its the stand alone unit.

 

[charlief1]

78 and 79 are sealed units and the 80 unit was mounted inside under the dash and isn't sealed.

 

[CTX-SLPR]

Just got a "close" copy of the rulebook.

Sensor controlled ignitions are allowed but shall be stock and not modified in any way for the year and model of the vehicle entered.

Sounds like I'd need an 81 model.

 

[iraceitall]

What rules are you racing under?

 

[CTX-SLPR]

What rules are you racing under?

SCTA/BNI