I'm going to a dyno/tuning shop very soon to get my car dyno'd and the shop is very well renowned for tuning LT1 and LS1 chips as well as Mustangs.

So my question is, does the LG4 have chip tuning potential considering it has an ECM and the carb operations are partly computer controlled? Would I see any noticable benefit if it is possible? Or would it be better just to physically tune the carb itself?

Thanks.

 

I would say that other than the spark table and part throttle 95% of what you are seeking can be done on the carb itself. Between the idle mixture screws, jets, secondary metering rods, hanger, AV door opening tension, and mixture control solenoid adjustments. You can also tweak the base timing. As far as the prom, get you a L69 computer and use it. Doesn't really matter if it is out of an F-body or a Monte Carlo SS. From the factory the L69 prom is about as good as you can get.

 

I think he hit it on the head.
There is not much to be done with thye ECM end of things. a little more spark may be nice but playing with distributor will get you that. The majority of the engine is running from the carb itself. I have an 85' and it kills me how much I can't do compared to my $8D setup of my other car. Barely able to log data and have to do hardware mods.

 

Good to know. I don't want to limit the amount of power I can make due to the ECM. Thankfully, it doesn't seem to be a problem.

Thanks for the advice.

 

Hey... I'm in the process of modifying part of the electronics for the q-jet ECM. I've built an adjustable voltage regulator for the vacuum sensor voltage. Will be experimenting with BARO and the MCS next and Oxy Sensor voltage. Any change on input voltage will effect the ECM output. All can be done at a fraction of the cost of a new chip. Recalibration of the carb will be needed and make sure you get yourself an Air/Fuel Ratio guage and mount it inside the car so you can see the results. If your interested in engine electronics....checkout http://www.jaycarelectronics.com/index.asp

Look in the carb section of this site for my other post.

 

http://www.customefis.com/maptrick.html

All you would have to do is add in a DPDT toggle switch to switch the polarity of the battery, rich for power and leaner for mileage.

 

Get a copy of the ZZZ retrofit manual, and use the ecm knock sensor, ESC module, and chip.

Then get Doug Roe's Quadrajet Book.

BTDT, spend years playing with it all.

The HP with the CCC is getting the seondaries correct. Getting the right rods, and hangers to be able to tune it, is going to be at least difficult. What I wound up doing was making some jigs, and fixtures to bend up all the right hangers.

Then if you want to get the carb to work for lat G's you'll have to reshape the float, and play alot of games with float levels.

 

Thanks Fast355.....Looks pretty simple, I'll check it out. I made three using the LM317 adjustable voltage regulator with a 150ohm resistor and multiturn trimpot. I think RadioShack has the parts but I order mine from DigiKey.

http://www.national.com/search/search.cgi/main?keywords=LM317

or

http://http://ca.digikey.com/scripts...?KeywordSearch

this is where I got the Idea!
http://www.rightcoastcrawler.com/billaVista/MAP/ADJUSTABLEMAPSENSOR.HTM

 

Hey Grumpy,
Been playing around with the Electronic q-jet for years and enjoy every minute of it! My next tweak is setting the Duty Cycle using a kit from JAYCAR. It will be mounted in guage pod for fulltime monitoring...but a volt/ohm meter with a duty cycle fuction will work. Still checking around trying to find out if this ECM has a LeanCruise mode for the q-jet...if not...I'm going to check out that option!
Does anyone have any ideas for this! Is it better to modify the Mixture Control Solinoid signal directly or what!

{http://www.jaycar.com.au/productResults.asp?whichpage=3&pagesize=10&keywords=&CATID=25&SUBCATID=347&form=CAT&SPECIAL=&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=

 

All you need it a regular dwell meter. The M/C pulsing is so slow that a normal meter reads it just fine. It's a very simple ecm.. You can send a phoney O2 signal to the ecm for whatever DC you want. I sound up being a few sets of the *The carburetor Shops* idle jet, and idle transfer kits, and building several carbs up to be able to do back to back testing. The secondary door opening, and having an adjustible limit were while additions....

But, I got all done, the fuel slosh in the flat chamber just stopped me from getting the car to run it's best. I fab'd up all sorts of different floats, and internal *fillers* for the chamber but anything approaching 1G was a head ache.

I did about all you can do to one, to include buidling jigs for secondary hangers, and collecting as many secondary needles as possible. While it was fun, it still was just so much more work then going TBI, that I made that leap, in like 91-92 to the TBI, and haven't looked back.

If you're enjoying it, great, but there are some serious limits to the CCC.

 

Yup..your right...it is a pile of work...and I'll probably go with EFI
later, but this old system has been quite the learning experience. It's a stepping stone for DIY Fuel injection..it's all about guys working on cars no matter what.. eh!

thanks alot...talk later...

 

If you are interested in tuning the electronics get the $40 hack from moates fileman. This is a hack of the 1228079 1987-88 CCC carb ECM. 2532 is a drop in PROM. Get these off of Ebay.

This carb has a lot of the physical limits of a carb but it improves the system (over a regular carb) by allowing electronicly adjustable timing, and electronicly adjustable "jet size" (metering area) Just turn off closed loop, add a wide band and adjust for the A/F ratio, and the timing the engine wants.

For max HP tweaking the base timing and secondaries will produce max power, but it is nice to be able to set up part throttle to what the engine wants instead of being stuck with what you get.

John

 

32V_DOHC, does Digikey or Mouser sell this EPROM? I'm having a little trouble locating it. Also I haven't bought TunerCat because it doesn't list this ECM, how easy is it to fool it into editing it?

 

Thanks guys ...I'll check it out on Ebay.

 

I found a couple of the 2532 proms on ebay for $7 each shipped, but can you guys recommend a programmer?

Also Thanks for the $40 hack 32_DOHC!, I've found TunerPro a useful tool to modify these bins, but I'm curious how you came up with the constants for the spark table, ie. how many degrees per bit.

 

Where do I get this TunerPro device...I think thats the way to go. Even if my CCC system seems primitive, its still a computer and needs some tweaking too.
Trumps2000...I tried E-bay my serch comes up zero. Help?

One more question...Where do I cross reference the codes stamped on the prom? I have one from MR. GASKET , 1988 Caprice CCC, and my stock Prom.. which I read was a very good chip and already maxed out for the 87 Monte SS.

 

Search Ebay for 2532 eprom, you'll see the But It Now for $7, selller super-genius!.

TunerPro software: http://tunerpro.markmansur.com/

This will edit a bin file. What I've done so far is create an ECM definition file with what 32_DOHC put together and used it to decifer some of the ZZ4 bin.

I'm a newbie at this as well and haven't done much of anything yet, but I figured too the computer needs some tweaking and for less than the price of a JET chip I could customize it. I bought an 8079 ECM and am waiting for these EPROMs to show up. Then I need to buy a programmer.

I don't know how to cross reference the numbers off the chips.

This is actually a backburner project for me. I need to buy up a bunch of parts to redo the steering, suspension, add C4 brakes and get it on the road, but with the weather the way it is, who knows when I'll actually get to do that stuff.

Hope this helps.

 

The "jet size" is still basically set by the main jets. While you can tweak the dwell slightly, you still have to change the main jets to make much of a change. The secondaries are strickly mechanical. Setting the air door up to be adjustible is a biggy. But, gathering up the hangers to make up a full set is a pain......

Not to mention, that the idle discharge ports are limited, the idle jets are fixed, and take some real skill to make to be replaceable, and the idle restrictors.

 

My comment about the adjustable jet size pertains only to non-WOT. At WOT there is adjustability but only to go leaner. At part throttle there is a great bit of adjustabilty. You only really need this if you are abandoning closed loop.

Idle discharge ports are like any other Qjet. Just drill them bigger. The idle screw will allow you to get whatever area you need as long as the hole is big enough.

Off idle is a different story. It is fixed and changes are made by mixture strength. This is where the IAB comes in to play.

The idle jet was not much of a problem. There are two ways you can get more fuel through the idle jet. Bigger jet or smaller air bleed (more suction.) The Air bleed is adjustable both on the carb and in the computer. Open area and closed area are blended by duty cycle.

The restrictor are only a problem when to small. Drill them bigger and trim with the IAB. Restrictor and idle/off idle area combine to regulate A/F volume. Change strength to change delivered fuel.

Set the IAB height on the carb so that transition from idle circuit to main circuit happens smoothly.

Set idle speed with the idle air bypass holes and not by cranking the primaries open.

Also watch out for cheap gasket kits. I have found some barnds don't properly connect the idle air bypass on one side of the carb. Needless to say this mess things up quite a bit.

These carbs are definately not EFI and in some respects it shows. Float bowls and venturis are downsides you won't ever really bring up to EFI levels but they will do things that a non-ccc carb and mech dist will not do.

HTH

John

 

Excellent info.....Are the Air bypass holes at the base of the carb? AIB is at the top...right! Does the mixture needles at the base control just air, or a blend of Air/fuel. I have mine turned way in which seems to lean it out, but I'm not positive if they control fuel or air.

Now were really getting into the CCC carb!!

thanks

 

Yes they are the round holes that don't have needles in them. Their function is to add enough air to allow the correct idle speed without over opening the primary blade. Bigger cams usually need these to be enlarged to bring up the idle speed and still allow the blade to be closed enough to not uncover too much of the transition slot.

The IAB is the adjustment at the top of the carb. It is a tube with a spring loaded pin inside. Air comes in from the side, travels down the tube and out the side. The pin touches the soleniod plunger. When the soleniod is off the plunger comes up. This raises the pin and blocks the outlet holes of the tube. This is the same as a really small fixed air bleed and draws more fuel through the idle jet richening the mixture. Turn the soleniod on and the pin retracts opening the outlet of the tube. This causes less fuel to be drawn through the jet leaning the mixture.

The needles control the volume of the fuel/air mixture delivered to the intake. The IAB controlls the strength of that mixture. The mixture is again diluted when the bypass air and the throttle plate leakage are added to the mix.

There is usually a fairly narrow range for the mixture screws. Turn them until the IAB allows adjustment from rich to lean or lean to rich. This is a rough adjustment. Fine tune to provide proper off idle strength. If off idle is too lean then lean the mixture screw slightly then trim the IAB richer. If off idle is too rich then richen the mixture screw slightly then trim the IAB leaner.

HTH

John

 

I'm a subscriber on the Olds G list.

I deleted it before I got it written down, but there are a few guys doing the Olds CCC stuff.

They have a yahoo group, so u might want to check out and see what they are doing.(have to search for it)

I would have to believe it is very similiar.

later
Jeremy