Timing a custom supercharged engine
 

Hey gents. I been eyeballing those Daytona Sensors style ignition boxes. I really like the features on them. You can pretty much set up a timing curve, like an EFI engine.

Lets say on my engines, where I have been running 34* timing, locked. By using the programming feature, I'd be able to set the timing to say 10* while cranking, which is easier on the starters/batteries. Then, as soon as the RPM hits 500, the timing can be set to whatever I like. I know my style engines love advance at idle, and really helps give a much stronger idle. Maybe, I could set them at say 36, or even 38*, between 500RPM and 1000RPM??

Then, as far as cruising, esp in the peak torque area, I can pull some timing out, maybe say run 30* between 4000-5000RPM. Then, after peak torque, start bringing timing back in. Possibly even be able to run say 36*, at say 6000RPM?

I guess what I am asking, what kind of timing map are some of the EFI supercharged guys running? I'd imagine when you're buying a Eddie Young, Alex Haxby, supercharged EFI monster, the timing isnt simply "locked". The start retard, higher idle lead, ability to add/pull timing in different areas, etc, is much cooler than locking it out. Im bored and want to do something to the engines this winter.

Take this with a grain of salt as it is from timing a turbo engine in a car, but we would use lots of timing at idle, and then almost have an inverse of the torque curve.

I think you are leaving a lot on the table as far as manners, safety margin, and performance running locked timing. I would be interested to see if you could actually run more boost safer with an optimized curve.

Knock retard would be the bees knees for ultimate safety but setting up the noise table can be a bit finicky.

I am considering adding a knock/timing retard system as one of my winter projects. I think this will be a simple add on and may work well. I am running an MSD Pro Billet distributor with an MSD6M box, locked timing, dominator carb. No electronics at all. Just as a point.... I run a secondary ignition coil that will fire without the MSD box, just in case I have a problem. I can isolate the primary system within a minutes worth of unplugging the primary and plugging in the secondary. Kind of like Nascar does.

http://www.jandssafeguard.com/NewUni...alVersion.html

Turbo cars get real fun when you activate a timing retard on the brake to get the egt's way up and spool the turbos ;) makes some funny noises lol

Antilagging a big turbo is fuking awesome. Try doing it at a stoplight when a Prius is behind you. :evilb:

Joe, my experience mostly comes from small blocks with blow thru's and big heads. That being said, since these engines typically lack velocity, I usually run 38* of lead / locked timing. Others around here are running more and taking out more per pound of boost and having success. A theory I've started to adapt to also.

Since the game plan is to get as close to knock as possible without running into it under heavy load, a knock sensor makes sense. But the big question is which one??? And how reliable will it be over 4000 RPM's??? My understanding to be accurate, is to have the sensor in the head. Toyota maybe the only one using these in mass productions at this point. I have to imagine big Chevy's EFI's factory knock sensor should be "tuned" to ignore noise. Though these are probably heavy knock conditions only since any change in factory bore size or piston type could change things. I wouldn't be surprised if the ecm is programmed to ignore the knock over 4k, that is if it's a high sensitive setup.

If i were to have my engine on the dyno. I'd research a system that meets my budget, give's me programmable spectrum / frequency flexibility and has ear muffs. This way I would have control. If your close to your dyno guy maybe he'll let you experiment on dyno pulls.

Good luck, this stuff is addicting.
Andy

Yep anti lag on the supra is good times!

Joe. Sometimes if it ain't broke don't fix it. You have a strong reliable combo. Hard to mess with that until something happens. Lol.

But then if it breaks ill be forced to build some bigger mills :-)

on the mefi4b's that I tune,,the knock retard is working all the way up.I use the data record func of the mefi hud display and mod tables to run it perfectly.no dyno,,just real world running tune.on my chit I run my engines lean enough to just tickle the knock sensor.

I love doing that in my dmax,no anti lag,,just on brakes and 10lbs of boost= gone when light turns green.

Tell justin to give you my "good" tunes no brakes needed :) just instant spool

I think you are on the right track. I would be very concerned running an SC engine with locked out timing. In an efi engine (speed density, ie, MEFI), everything is based off of MAP (manifold absolute pressure) Timing is based on load. Take a supercharged efi engine making roughly 1000 hp. At 100 kpa (no vacuum, no boost), it may have 30 deg at 5000 ramping up to 35 deg at 6000 rpm. Depending on boost, it may have a small negative number to remove some timing once it is in boost. That may only be 1-3 deg. That will depend on rpm and boost. The higher the boost and lower the rpm, the more negative the number (taking out more timing) At higher rpms and lower boost levels, no timing is taken out.

Now, at a Kpa level lower than 100 ( in vacuum) the timing may be 36-40 deg. The lower the Kpa (more vacuum) the more timing it will have. So, at 5000 rpm and 80 Kpa, it may have 38 deg., at 90 Kpa it may have 35 deg and at 100 Kpa it may have 30 deg. Anything over 100 Kpa is boost. If the boost is say less than 5-6 psi, than the timing may stay at 30 deg. If boost is over 5-6 psi, you may start taking out 1-2 deg. That may also increase as boost increases.

This is what really sets efi apart. There is unlimited tuning to be done to the spark curve. You can add as much as it wants when the load is light ( high vacuum) and then start taking it away as load increases. As rpm catches up, you can start putting it back in.

Also, with the Mefi (not sure about others), it has what's called "idle spark stabilization". This will add or remove timing to keep a smooth idle and prevent the engine from stalling. You can program it to add as much as you want. It's not uncommom for it to add 20+ deg and raise the timing to 40deg at idle. It's really nice when you have a boat with 41" props and 1.24:1 gears. It's a tremendous amount of load when you put it in gear. The IAC will open up and the timing will come way up to keep it idling so that it may only drop 100-200 rpm from neutral. With a carb engine, you would look like you are swinging numchucks on the throttles.

Of course, you also have the protection of a knock sensor. With the Mefi, you can not only control when it listens, but the sensitivity of it. You can compensate for a noisy solid valvetrain, drivetrain noises, etc. You can change the temp at which it listens if you have a worn out engine with some piston slap when it's cold......and on and on. It will do just about anything you want it if you spend the time.

Hope this helped shed some light on it. I tried to simplify it as much as possible.
Eddie

Eddie, thank you VERY MUCH, for taking the time to put this information up. I remember last year, discussing this with you on the phone. Its much clearer to me, when I can go back and read it.

I noticed the Daytona Sensor box, has an option to add a Map sensor if wanted, so you can build a map based on boost/vacuum, not just RPM.? What I like about that, is that in my particular combo, the RPM/Load scenerio, isnt constant. I may be cruising on calm water, with a light load, at 4000RPM, and 100KPA. However, fuel tanks of fuel, some rougher water where I may drop the tabs, tuck the drives, and now Im making 3psi of boost. So, even though the RPM is a constant, the manifold pressure isnt always.

I did notice the Daytona Sensor box advertises a "Idle Stabilization" feature.

Even though my setup has been working good, and hasnt broke anything, I'm always willing to try something new. I really like the idea of being able to crank the engine over with say 10* of advance, and as soon as it starts the timing can be increased, to whatever I like at idle. Even though I dont have super high pitch props, or the tall gears, dropping it in gear with the 17" SSM props will sometimes want to kill the engine.

Aside from adding some complexity with the tuning (which I am sure you are more than capable of), I really don't see a down side to doing this. What are you figuring, about a grand a motor all in as far as cost is concerned? I mean hell, even if it wasn't your bag, you could make a straight 34 degree table and be back where you were.

Actually, that might even be kind of cool to just quantify the difference in manners, economy, and performance between the two. Crap, now you have me geeking out on this.

Then it sounds like a no brainer to me. Especially if it can reference a MAP sensor. That will make all the difference in the world. Using your example of cruising at 4000 rpm, you could potentially see a difference of 3-5 deg of timing. If the MAP is at 90-100 Kpa, you could possibly run in the 35* area. If the load is higher because of a heavier load (mulitple fat chics) or you are dragging tab (being a *****) and the boost comes up to 3-4 psi, you would want to drop the timing a few deg to say 31-32*, since there is no knock protection. This would help save the engine in the high load situations, but allow you to make the most of economy when cruising with it trimmed out.

Let me know if you decide to pursue it. I would be more than happy to help as much as I could or supply you with a timing vs rpm vs MAP table to get you started. Sounds like it could be a really cool project and a worthwhile upgrade.
Eddie

The Daytona Box works with the TBolt Dist's. Big plus. Some others don't.

Another big plus is that they sell a phased TBolt rotor. Back when it was a Crane Box (Crane wasn't programmable but it had a bunch of different curves you could chose just by turning a dial) , you had to mod the dist rotor yourself. This was a big turnoff to some people.

I've been close (mentally) to buying the Daytona Box even for my mild small block. Has great features.

I used to have a Crane HI-6M (made by Daytona Sensors) and that was dead realiable and a great box.

Nothing like good box ! LOL.

I think I'll definitely be calling if i buy them. I understand the features it has, and the principle behind it. However, setting up a multi dimensional timing map, I'm gonna need some help! Thanks !

I have the Crane Boxes now. They are the 6000-6440 box, without the built in ign curves. But it does have the internal rev limiter. I've been extremely happy with them, they just work. Just feature limited.

thanks mild,now you have me think about droping 1500. bucks and try this.

Anytime I can get a friend to spend money, I feel great! Mike, I think you might be a perfect candidate for this. You think Dave down at the dyno would be up for playing with this setup? Maybe when we can bring yours down to the dyno, and skype Eddie in for some live tuning assistance

Yeah, hes good for coming up with ideas to spend my money on !!

:violent-smiley-021:

It's always more fun when someone else is paying !

Yes, but think of all the good deals I find you! Even though your spending, your saving!

You're starting to sound like my wife. She walks in with 2 arms full of bags and says "guess how much I saved". I don't want to know what you saved, I want to know what you spent.

I would be more than happy to help out on Skype, or in person if the timing is right. Just let me know.
Eddie

This thread and the dyno thread are great. Informative without bashing.

i need to check the piggybank because this might get expensive.

Joe, with timing control you're just one step closer to the dark side.. :evilb: Once you experience being able to have almost any amount of timing at any rpm and load, you know you're going to want to have the same control of your AFR... And I don't mean having a nice consistent curve, I'm talking about being able to idle at 14 and have it drop to 12.5 the second it goes into gear, then climbing back to 13.5 while you're idling through the no wake zone. Having it rock solid when getting on plane, and being able to command any AFR you choose based on load and rpm. AFR adjusting for coolant, and air temp, while the timing adjusts automatically for air temp as well. Because this is the logical progression, it would be worth considering purchasing a Holley HP ecu and wiring harness. You can use it with your carbs until you're ready to make the inevitable switch. It will do all your timing controls, programmable knock, guardian type system, instead of a buzzer that goes off when you're down to 6#'s oil psi like the factory, you can program it for any pressure you want, fuel pressure, air temp warning, etc. Massive datalogging capacity, IAT, AFR, timing, knock level, coolant temp, oil temp, etc. Wanna try meth injection instead of an intercooler (yes you do) it'll do that too. Then when you're finally ready to give up carbs, you and Mike T can drill some holes in your carb adapters, pick up some universal fuel rails, and buy some throttle bodies. Food for thought...

i use to do in on my rx1 (snowmobile) to get the phuckin person ahead of me to move over,,damm slow pokes..

I did not know that was possible with the Holley unit, to run with carbs! Oh man. Now look what I started. This chit is getting out of hand quickly ! Good info! :D

can you tell us (me) more about the holley, I just looked up some info on the holley hp. I only thing I have found is efi info.
where can I go to find more about using the holley hp with a carburated set up?

Down here we refer to all this new technical stuff as "The miracles of modern science"
This reply is over the top in completely controlling every aspect of the fuel delivery.
We've certainly come a long way since we were learning how tune our 4779's by reading the porcelain's color and watching the vacuum gauge.
Thanks for the heads up on that fuel controller, it sounds like an awesome piece.

See ya,
Kelly

Joe, as you have been kicking around the daytona sensors upgrade so have I. Almost pulled the trigger a couple times. I'm glad I didn't. I spent alot of time tunning and working bugs out the last couple of months my main issue was detonation on cylinders 5,6&7. I went through so many plugs I should have bought stock in autolite I'm sure my purchases alone would have got me a return on my investment. I finally did get the detonation taken care of with a 20% mix of race fuel and 93 pump gas. If I had more control over the ignition I think I could do a little better on the percentage. So, with all the blood, swet, tears and curse words over the last couple months I've come to the conclusion that I'd like and ignition that I can control each cylinder individually...

Just bringing this thread back up. I found that MSD also makes a box that is programmable as well, and has the Map sensor option.

http://www.msdignition.com/Products/...ble_6AL-2.aspx

http://www.summitracing.com/oh/parts/msd-6530/overview/

personally I would stay away from the MSD stuff...seen to many issues, and if/when you go EFI will be useless, as nothing MSD and EFI ecms seem to like each other(RF interferance) but when we were playing with our timing curve, did 15 @ start, then 36 idle thru 3500(had boost here) pulled it back 34..32..then 30 @5200, did not have knock sensors so just making sure no det @ full boost...Rob

What about a marine version?

Yea, no marine MSD version of a programmable box. Daytona Sensors is marine approved i believe.

Keep in mind too that the conversion for map to vacuum is roughly 3.3" per 10 kpa so IF you did this and wanted to drive the boat tuning with your vacuum/boost gauge if you were crusing at 6.5" vacuum it would translate to 80 map/kpa or so, 10" would be 70 map/ kpa when you go after timing tables based on map/kpa, fwiw, Smitty

I like.. very interested... You, Mike T, and ICDEDPPL, get this all scienced out so I can jump on the bad wagon,,,,
Just to note... MSD NON marine boxes can be sent in to be fixed. Whereas, the Marine ones are filled with some composite material and therefor can't be fixed. So whatever way you guys decide to go please do take that into consideration.. I do Like MSD.... lol

Ok,I thought I would bring this back up. Its almost spring and was wondering if you guys have gone in any direction with this yet????