true timing control-REALLY!!!

[markaboo929]

ever wish you could try to control your 4.0s timing?welll maybe you can get a slotted crank sensor or get a chip or put a resistor in line with the coolant and intake air sensor.i have found a product ment for turbo buick GN and gm v8s called a spark translator that goes in line to intercept the signal from the ecm to the ignition module to control timing -advanced or retard-i purchased one to see if it would work on my 88 renix system and i am very happy that it does-guinea pig for me i guess-it deffinetly makes the timing adjustable sooo in conclusion it can be purchased from www.fuelsystemparts.com do a search for spark translator it costs 179.99 .they do also have a control box for gms that use a crank sensor and alters that signal from the sensor to the pcm and controls timing in that manner so it may work for non renix from 91 up that costs 249.99 so i dont know if it will work on those motors but it should have the same prinsiple as the gm sensors.i currently have an 88 xj that has only external mods my set up is as follows
home made map sensor adjuster $13 in parts
the spark translator
26 lb gm ls1 injectors
no cat
free flowing muffler
i know that the injectors i am using sound to be too big for a stock non stroker motor but my map sensor is set at 3.09 volts and i fogot to mention that i work as a master tech at a gm dealer that happens to have a dynojet dyno on site to test right now i am at @13:1-13:3 just about right as 12:9-13:5 is where best power is made-guess why all the car makers want the ratio at@14:7-1 because that ratio is where the catylist in the converter works best not for power or economy but for the cat!!!!to make the air clean if you have anything to add or ask let me know

 

[CRASH]

Are you running 13.2 at WOT or at all times?

That's great for WOT, but your just wasting fuel if you are running that rich at cruise mode.

Interesting info on the timing controler, thanks.

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[markaboo929]

actually it is that all across the board . go figure .what a map adjuster can do for so little money

 

[markaboo929]

yeah i know that is a little rich but much better for cooling the cylinders plus i have a crane ignition set up so at cruise it gets burnt pretty well i have not had it on the dyno since i installed the timing controller we'll see

 

[markaboo929]

plus don,t forget that the more power an engine makes it also burns more efficient as well 14.7-1 is for cat effieciency that number is where the catylist works best so thats why most engines can produce more power with more fuel/more air /more timing etc... which means slighly rich if you would say---lok at late 60s engines and thier power numbers-before cat days.......

 

[CRASH]

plus don,t forget that the more power an engine makes it also burns more efficient as well 14.7-1 is for cat effieciency that number is where the catylist works best so thats why most engines can produce more power with more fuel/more air /more timing etc... which means slighly rich if you would say---lok at late 60s engines and thier power numbers-before cat days.......

14.7 to 1 has little to do with catalyst efficiency. It is the stoichometric efficient rate for unleaded fuel air mixture. The fuel is at its maximum atomization for optimal power.

Stoichiometric or theoretical combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted.

The reason that most computer controlled vehicles go to a fatter mixture under WOT is to protect against lean spots in the chamber that develop right at the ideal stoich. If you have good internals (forged pistons in particular) you want to run as close as you can to stoich at all times and not drop into the WOT mode at all.

I used to run an adjustable MAP for my stroker, but got rid of it when I realized I was running stock voltage through it, and my A/F (as read through my wideband) was spot-on perfect with just the OEM MAP voltage. Mine happens to drop to 13.3 after 3 seconds of WOT. If anything, with my forged pistons, I'd like to be a bit closer to 13.8 to help eke out a bit more power.

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[JeepSpeed]

plus don,t forget that the more power an engine makes it also burns more efficient as well 14.7-1 is for cat effieciency that number is where the catylist works best so thats why most engines can produce more power with more fuel/more air /more timing etc... which means slighly rich if you would say---lok at late 60s engines and thier power numbers-before cat days.......

Yeah, exactley, their power numbers sucked. Are you forgeting the size of these engines? Take a 455 cu/in engine from the 60's, and a modern 455cu/in engine, use the same scale to rate their power (SAE vs. Net or whatever), and I guarantee the modern engine bitch slaps the old one. With a cat.

 

[markaboo929]

1969 corvette 5.7 L46-350 hp 2004 corvette 5.7 LS1 350 hp go figure? :wave:

 

[markaboo929]

well on the dyno at my work when i was at 14.7 my 4.0s torque was 30 ft lbs less than when it was 13.2 i am not arguing on any issues just that what works for someone my not work for everyone.don't forget that brand of fuel grade of octane elevation temp and humidity ALL have an effect on every different situations like for example i am running 26 lb ls1 injectors too big? not for me and with map sensors don't forget that the less vacum(wot) it retards timing and more vacum(slight throttle) it advances it just a thought.no "mind" wars if you will :rattle:

 

[markaboo929]

oh yeah check out this web page too http://carrito.net/hp_calc.htm

 

[markaboo929]

or this page www.splitsec.com/faq.htm

 

[CRASH]

But you do realize that the adjustable MPA only performs a service when the coimputer is in WOT mode, right? That is the only time the engine is disregarding o2 sensor signal.

The rest of the time, as the MAP tries to enrich the mixture, the o2 is trying to keep it as close to 14.7 as it can.

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[markaboo929]

but there is a crossover that can be "adjusted " to where it will stay what you set it at i can adjust my map at idle and see an instant change and it will stay there even at idle it will make a difference also the renix system operates different from chrslerized ecm operating peramaters like the o2 reads different voltage as does most systems 0f .1-1.0 being .45 in the middle of rich and lean that is the renix o2 which is the set up i have

 

[markaboo929]

ever take map vacum line off of the map at idle? try it it goes to dead rich notice some black smoke at the tailpipe? if the voltage is lower than 5 v reference volt it will change linearly as well being say only 3.5 volts at WOT which in turn will be leaner than 5v at WOT vise versa with more than 5v as reference volts. i know that 14.7 is more efficient for emmisions wise but for power well do some searches on line for best air fuel ratio for max power last night on the dyno here at work a 2001 transam came in with head and manifold work done cust had it set @15.5 14.9 on the dyno he had 245 rear wheel horse power we adjusted it to @12.9 to 13.2 guess what he now has 305 positive results just from air fuel ratio differences.

 

[CRASH]

but there is a crossover that can be "adjusted " to where it will stay what you set it at i can adjust my map at idle and see an instant change and it will stay there even at idle it will make a difference also the renix system operates different from chrslerized ecm operating peramaters like the o2 reads different voltage as does most systems 0f .1-1.0 being .45 in the middle of rich and lean that is the renix o2 which is the set up i have

I also have a Renix.

I have not experienced this "crossover" of which you speak.

The only way you can defeat the o2 sensor leanout is to increase voltage to the MAP to a point where you exceed the mapping parameters of the o2 sensor. At that point, it's gonna be running pretty darned crappy.

Why not just remove your o2 altogether and replace it with a constant voltage reading in the middle of it's mapping? This would allow you to adjust to your hearts content without battling the leaning function of the o2.......

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[CRASH]

ever take map vacum line off of the map at idle? try it it goes to dead rich notice some black smoke at the tailpipe? if the voltage is lower than 5 v reference volt it will change linearly as well being say only 3.5 volts at WOT which in turn will be leaner than 5v at WOT vise versa with more than 5v as reference volts. i know that 14.7 is more efficient for emmisions wise but for power well do some searches on line for best air fuel ratio for max power last night on the dyno here at work a 2001 transam came in with head and manifold work done cust had it set @15.5 14.9 on the dyno he had 245 rear wheel horse power we adjusted it to @12.9 to 13.2 guess what he now has 305 positive results just from air fuel ratio differences.

I understand your point. I'm telling you that I run 13.3 at WOT. What I don't understand is why you'd want to pour fuel out the window by running 13.3 at all times? How does that make any sense?

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[markaboo929]

what i am talking about is power not fuel economy be it true that slightly rich may in a sence be wasting fuel thats not what my whole discusion is about 14.7 is for fuel economy which maybe chemically ideal for complte burning of the fuel in the mix if you chaeck almost any discusion on air fuel ratio for engine power it will be under 14.7 i can cruise with slight crack of the throttle at 65 mph @2500 rpm with trans in 5th-overdrive-4.10 gear ratio maybe 30 inch tires-says31 on the side .and just push the pedal down to 1/4 throttle and accelerate quite quickly to 75-80 mph in a snap may it be that there is enough fuel readily available for instant power responce it works for me also in a stroker motor isnt there a chance for detonation if it runs to lean?not to get to nutty on this subject i just had some info,or an opinion,on trying to extract as much power-not economy-out of our motors.i do not think this is a knowlege issue but just relaying some info that i had experienced .

 

[JeepSpeed]

1969 corvette 5.7 L46-350 hp 2004 corvette 5.7 LS1 350 hp go figure? :wave:

Horsepower was measured in different ways back then. Someone else back me up on this. I beleive it was called "net hp", and it always showed much higher numbers than the modern rating does(corrected, or SAE, or something like that.) Also, that was with leaded gas. Not trying to argue, but you are simply wrong. Modern engines are more powerful than they ever have been. It's a misconception that "muscle cars" were the fastest things ever. Other factors involved, but most muscle cars ran 15's or 16's in the quarter off the showroom floor.

 

[CRASH]

Horsepower was measured in different ways back then. Someone else back me up on this. I beleive it was called "net hp", and it always showed much higher numbers than the modern rating does(corrected, or SAE, or something like that.) Also, that was with leaded gas. Not trying to argue, but you are simply wrong. Modern engines are more powerful than they ever have been. It's a misconception that "muscle cars" were the fastest things ever. Other factors involved, but most muscle cars ran 15's or 16's in the quarter off the showroom floor.

In the old days, it was measured as SAE gross. No accesories on the engine.

Now it's measured SAE net, with alternator, PS pump etc.

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[CRASH]

what i am talking about is power not fuel economy be it true that slightly rich may in a sence be wasting fuel thats not what my whole discusion is about 14.7 is for fuel economy which maybe chemically ideal for complte burning of the fuel in the mix if you chaeck almost any discusion on air fuel ratio for engine power it will be under 14.7 i can cruise with slight crack of the throttle at 65 mph @2500 rpm with trans in 5th-overdrive-4.10 gear ratio maybe 30 inch tires-says31 on the side .and just push the pedal down to 1/4 throttle and accelerate quite quickly to 75-80 mph in a snap may it be that there is enough fuel readily available for instant power responce it works for me also in a stroker motor isnt there a chance for detonation if it runs to lean?not to get to nutty on this subject i just had some info,or an opinion,on trying to extract as much power-not economy-out of our motors.i do not think this is a knowlege issue but just relaying some info that i had experienced .

Good, nutty discussion is what this forum is all about! It's all fun, and we all build for different reasons, so there are no hard feelings or anything. Good discussion!

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