Any msd pro data+ users around?
i'm looking for some info/help if possible as to suggested safe ignition curves /max timing figures as a starter to get me going if anyone can advise thanks?
stock compression ls1, 220/220 cam with .510" lift, so its pretty mild. rev limit suggested to me is 6400 rpm or so, i have arp rod bolts. inlet is GM performance with a demon 750cfm carb, mech 2ndaries.
some msd info i have shows the basic timing pills have something like the following advance points already set up ie no1 pill
rpm deg
1000 20
2000 26
4200 33
6000 35
6100 35
however i've tried a stock fixed pill no1 already and got some pinking on uk fuel above 5k revs. our dyno guy has mapped efi versions of the ls2 and ls7 engines and told me that top end timing never went above 29 degrees on those while making good safe power on our uk fuels.
i've also been advised to hook up the map sensor for vacuum advance to clean it up at part throttle, and maybe take it up to as much as 40-45degrees advance on light throttle to make it run clean. altho i've looked at the software i'm not 100% sure as yet how to work the vac advance part just yet. my demon carb has a timed vacuum port plus a constant vac port, i assume the timed port is the one to use so its not adding lots of timing in at idle?
just looking for any thoughts /advice really from anyone who has had experience of setting up their own timing maps etc.
cheers
Thats one article i have read. I would become a member there and post some questions for tuning there. That's what i plan on doing. I've had alot of trouble with the couple demon carbs i have had. I got rid of both of them because i couldnt get them tuned right and just switched back to vac secondary hollies.
i started with the edelbrock box on my swap, but i could not believe how much timing was built into the edelbrock box with the chips,, by the time you got above 5800 rpm all the chips had over 34* of timing and some of the chips had more yet
from what i have noticed most LSX engines like 27-29* total advance at WOT, so i picked up the 6010 box and programmed my own curve, here is a copy of it, you should be able to open it with your msd software, mine has a map sensor to give it a few more * of timing when cruising or high vacuum conditions only and i have a nitrous retard of 6* when activated.
this file has about 18* of timing at idle depending on vacuum
the file is in zip formatt so unzip it first
i wont be using nitrous so i will have to make sure that option is turned off, is that activated by a switch wire to set the msd back?
cheers for help
Thats one article i have read. I would become a member there and post some questions for tuning there. That's what i plan on doing. I've had alot of trouble with the couple demon carbs i have had. I got rid of both of them because i couldnt get them tuned right and just switched back to vac secondary hollies.
suprised you had probs with the demon, what happened when tuning? mine has been used on an engine on a dyno, to prove the carb is ok, made 500bhp using my setup, so i'm hoping it works properly on mine with the new 6010 box.
i started with the edelbrock box on my swap, but i could not believe how much timing was built into the edelbrock box with the chips,, by the time you got above 5800 rpm all the chips had over 34* of timing and some of the chips had more yet
from what i have noticed most LSX engines like 27-29* total advance at WOT, so i picked up the 6010 box and programmed my own curve, here is a copy of it, you should be able to open it with your msd software, mine has a map sensor to give it a few more * of timing when cruising or high vacuum conditions only and i have a nitrous retard of 6* when activated.
this file has about 18* of timing at idle depending on vacuum
the file is in zip formatt so unzip it first
i also noticed you have a quite high rpm limit at 7500rpm, have you done some work to your bottom end to take those revs?
i'm looking to rev to about 6400 as a maximum so will adjust that
rgds
chris
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stock bottom end with arp rod bolts, pulls to over 7000 rpm like nothing
I'd say 7k max since it's an LS1 bottom end. That's what i'm going to be spinning mine to anyway. You could probably even go 7200 since you're cam isnt as high a light.
Jay what did your S10 weigh? Those are some nice times man!
I couldnt get it to idle, took it to a guy who kind of new demons, he made it worse so i just took the carb off and sold it. Haha i didnt even make it to jetting or anything like that. I had too many other carbs laying around to justify wasting time with that one. (The engine was a 454 i put in a 1968 C60 dump truck so mechanical secondaries just werent the best anyway)
i need to find out now how much advance to add in around idle/part throttle via the vac/map sensor, and how that affects the idling etc. i have a wideband lambda of my own i can play with, but no jets and i'm not 100% up on these demon carbs (or any carbs to be honest as this is my first v8 carbd car).
any thoughts on how much advance might be added under vac/light throttle , i see your file looks to be adding about 6 degrees?
regards
any thoughts on how much advance might be added under vac/light throttle , i see your file looks to be adding about 6 degrees?
regards
i need to find out now how much advance to add in around idle/part throttle via the vac/map sensor, and how that affects the idling etc. i have a wideband lambda of my own i can play with, but no jets and i'm not 100% up on these demon carbs (or any carbs to be honest as this is my first v8 carbd car).

