My v6 Drag Week build

[c2xejk]

I will try and send it out tonight.

The car seems to prefer to idle in the 12.5 range, but I may be able to lean that out to low 13's if I am not worried about it leaning itself out. Right now too lean and the idle RPM likes to wander/oscillate...

So far as I crank up the spark advance idle vacuum has increased. I had been running with advance in the teens and have been slowly jacking it up... I am hoping that as I increase SA, I might be able to lean the idle AF... but time will tell...

[Sundance 6g72]

That would be awesome.

I too found the richer idle to be easier to control. Im not sure what the pulse width was on my injectors at the time but im sure it was very low if i tried to run lean!

[Ondonti]

With no actual idle control I have the exact same issue with idle. I tried messing around with it and I found that if I increased the fuelling @800ish rpms and leaned it out at 1000 while also having a LOT of fuel in the bins @ 800 rpms that are low vacuum (for when the motor starts to stumble) this prevents it from going into that zone. I got the idle much higher, bounding around 14-15 but then I had 2 random shutoffs where it was hard to restart each time. I was relying on my 1000 rpm idle zone to be lean and the 800 to be rich (especially in the low vacuum). That prevented the massive oscillation I was having when I tried to lean it past 12:1.

Ed, are your plugs really sooty black if you do a lot of idling?

My next goal with MS to mess around with testing the idle stuff to see if I can get it to behave like it should. I don't even know if mine obeys commands.

[c2xejk]

Everything I have read indicates that idle generally likes to be a little rich... Makes it more stable... That said, they are generally talking in the 13's...

I have not checked my plugs recently... that is on my todo list...

One thing I forgot to mention is I have switched from the standard accel enrichment to the Enhanced Accel Enrichment (EAE). Now that I have it tuned, it does a MUCH better job. AF doesn't spike ask much in either direction and on decel it cuts fuel some avoid the rich spikes there.

[Shadow24]

Might I also get a copy of your project tune to look at? I am specifically interested in the EAE part.... (shadowplane676@gmail.com)

Regarding SA though, IIRC, my spark map was in the high 20's to 32* on the 3.0 24v. I do recall at one point I had accidentally enabled knock detection (with no sensor connected) and it pulled like 10-15* SA on me and it gutted the power on the motor. Once I corrected that and got back into the 25-32* SA range, it woke back up.

I also was falling into the mid-12's for AFR to maintain a decent idle, so this leads me to believe that is possibly correlated to the overall engine design.

[c2xejk]

Email sent...

PS. If you see anything that looks odd, let me know.

[Vigo]

I guess those engines might need to run richer because of their goofy large port CSA killing VE at low rpms, but that is a wild --- guess. A few months ago i put a Weber carb on my 86 CRX and with the wideband it was perfectly happy idling in the 14s even cold and would idle in the 15s warm with a tiny decrease of smoothness. From the factory all of those 24v 6gs idle around stoich anyway although im sure they have more advanced controls keeping them in the desired rpm range on top of just fuel control.

[Shadow24]

The latest MS firmware has increased adaptive idle control as well, might not be on par with post 2000 OEM ECU's but it is getting quite refined. I will definitely be looking into that to help maintain a better idle on "Lucy 2.0" soon. That might help narrow down the idle AFR range and possibly get better idle fuel consumption. I know my tune's biggest MPG weakness is in the idle/warmup and accel enrich areas.

[Ondonti]

The latest MS firmware has increased adaptive idle control as well, might not be on par with post 2000 OEM ECU's but it is getting quite refined. I will definitely be looking into that to help maintain a better idle on "Lucy 2.0" soon. That might help narrow down the idle AFR range and possibly get better idle fuel consumption. I know my tune's biggest MPG weakness is in the idle/warmup and accel enrich areas.

Well I know its easier to get a smooth idle running rich but the sooty plugs that I saw are not a positive. I am not a nature nut yet I don't like the idea of burning that extra fuel just because I don't know how to figure out the "right way" to run it leaner. :P

With no idle control the motor really hunts for idle because it has no way of compensating except moving around in the different load cells. That is what my motor was doing last week when I was messing with it. When I started leaning it out, rpms would drop off and i would get into the very high KPA load tables until it got enough fuel (map was richer towards 100kpa) and that would kick the motor back to life and rev it back up again. That is why I said above that making a "wall" of rich cells just above my idle load cells prevented it from going up there even when I leaned out things a bit. Then it started going from 800 to 1200ish fairly violently and that required adding fuel at 800 rpms and keeping 1000 cell lean. That way 800 got the "kick" of fuel and 1000 would lean out and decrease power output meaning the idle wouldn't jump up so high. This made it a lot smoother and warmed up I got 14-15 AFR with a small (not smooth) rpm wander.

From that VE table experimenting it makes me think that MS is not able to compensate fast enough before the engine would fall/rise/wander into the next load cell. My reasoning for this is that I believe I had those cells (800 rpms, 50-80ish KPA) set based on lugging around the engine at very low rpms and NOT for idle control. That means the VE for those locations should be correct when the motor is held stable by being in a gear pushing against a load.

If my 4 wire AIS was actually working correctly that would be interesting. I know Joe was not running any idle control.

[Shadow24]

IMO - running an IAC with adaptive idle on the MS should give stock or better idle performance (on my "to tune/setup" list). I did what Ondonti did with the VE table and base idle screw for a while before getting a working IAC setup, it worked, but not real well...

Ed, what are you running for a TB on your 6G74 again? stock Mitsu 65mm?

[c2xejk]

A 60mm Jeep TB. The stock TB had a BUNCH of other devices hanging off of it. Plus the Jeep TB uses the style IAC I already had wired up.

Rather than messing with the base idle screw, the IAC step vs coolant temp table would be better if you have an IAC wired up. That said, I much prefer the closed loop idle control. The idle is always spot on regardless of the accessory load (alternator, ac compressor, power steering pump.)

[Shadow24]

Ahh, gotcha, I know what you mean with the TB, I stripped like half of the stuff off of it when I put the 6G74 65mm TB on my manifold. The IAC is similar to the Jeep 4.0 valve I used before, but has dedicated power wires, so switching over was easy. Do you think the 60mm is a restriction with the turbo in your case? I figured with the 3.5 and a turbo you would have gone up in TB size rather than down...

The IAC and closed loop idle control are great features on the MS that I should finally get around to implementing this time

[Ondonti]

On a turbo car I really only see drivability and IC piping size as your main factors in TB size. Don't put a TB on that is a restriction compared to your IC piping, but if your IC piping is excessively large (3" is enough for 1300whp...) then don't put on a huge TB when your plan is 300-400hp.

[Sundance 6g72]

On a turbo car I really only see drivability and IC piping size as your main factors in TB size. Don't put a TB on that is a restriction compared to your IC piping, but if your IC piping is excessively large (3" is enough for 1300whp...) then don't put on a huge TB when your plan is 300-400hp.

of you mean dont do what i did lmfao


Yes I had no idle control and was usually fine. In the cold I helped it idle and if I had a rough tune I would have to help it idle in the summer until it warmed up. Usually I just dealt with it rather than fixing the problem.

[c2xejk]

Ahh, gotcha, I know what you mean with the TB, I stripped like half of the stuff off of it when I put the 6G74 65mm TB on my manifold. The IAC is similar to the Jeep 4.0 valve I used before, but has dedicated power wires, so switching over was easy. Do you think the 60mm is a restriction with the turbo in your case? I figured with the 3.5 and a turbo you would have gone up in TB size rather than down...

With an normally-aspirated car, yeah larger throttle body would have been the way to go. With a turbo, it less "necessary..." As it stands the throttle is pretty touchy. If I go larger I will definitely need a progressive linkage, which would likely mean I go with an Inifiti TB.

The IAC and closed loop idle control are great features on the MS that I should finally get around to implementing this time

Closed loop idle is not to bad to tune...

My goal is to have the car tuned well enough that my wife could drive it and be "comfortable" as long as she doesn't spool the turbo's... That means it needs to start and be well mannered from cold to hot.

[Vigo]

Yeah, on an n/a 3.5 i would say a 60mm is too small, but it's probably just right for 2.5" intercooler plumbing and like Brent says, on a turbo car it's not as much of a concern since it doesnt have to flow all the air into the motor at a tiny pressure differential of <1" mercury. When you put a turbo on your inlet size concern goes to the turbocharger, and it's a bit different because the turbo generates a stronger pressure differential across the inlet than an engine does, so you can flow more air through the same size opening as an equivalent size throttle body on an n/a engine.

Stock 8v motors with stock garrett turbos can flow 300chp worth of air through a 42mm inlet, but if you made a wild nasty n/a motor and put a 42mm throttle body on it you wouldnt get as far.

[Sundance 6g72]

Ed, I am going through your tune and my tune right now. I stole some things here and there but one thing that I am curious about is the MAT correction table you mentioned a little bit ago. This is a screenshot of mine (pretty much a complete copy of yours)



Im not sure how this table even works. I would think that your average daytime temp (or the temp you tune at) would be set to 0% correction but im not even sure what the purpose is. The % numbers in the table seem HUGE as far as fuel correction is concerned. I cant test this in a car right now otherwise I would. I have never noticed a large variation in AFR when comparing morning to peak temp during the day. I usually drive with EGO correction turned on and give it about 5% authority over my fuel map. It generally does a good job and keeps me in my target AFR as long as my map is already close enough.


Also, im not sure if this is common knowledge or not but the "warmup enrichment" and "Cold ignition advance offset" tables share the same coolant temp values. I didnt know this for the longest time. I would tune my Warmup settings and then work on my Cold advance after. With warmup enrichment I would set my last two coolant temp values to 180 and 210. Both values would be set to 0% enrichment.

With my Cold Advance table, I would go much further than 200*. My highest value for coolant temp is 250* with a -3 advance. This lets me pull timing when the coolant gets too hot. Im not sure if this is proper practice but it made sense to me. I guess I could always pull timing via intake temp if needed but I never go above 100* (I maxed at 95* intake temp ON A DYNO during my 2nd pull... The street usually sees ambient or plus 10 tops). My point is that everyone should be careful to watch those two tables because it would mess up my warm up settings because they share the same coolant temp values.


edit: also, I notice you are not using overboost protection. Im sure you'l never have a wastegate fail on you but it might be a good idea to turn it on. Ive used it and tested it (willingly and unwillingly) and it works very well, almost too well.

[c2xejk]

Ed, I am going through your tune and my tune right now. I stole some things here and there but one thing that I am curious about is the MAT correction table you mentioned a little bit ago. This is a screenshot of mine (pretty much a complete copy of yours)



Im not sure how this table even works. I would think that your average daytime temp (or the temp you tune at) would be set to 0% correction but im not even sure what the purpose is. The % numbers in the table seem HUGE as far as fuel correction is concerned. I cant test this in a car right now otherwise I would. I have never noticed a large variation in AFR when comparing morning to peak temp during the day. I usually drive with EGO correction turned on and give it about 5% authority over my fuel map. It generally does a good job and keeps me in my target AFR as long as my map is already close enough.

When I started this table was flat lined at 0%... I bumped it up to the point that certain times are a little rich and I am starting to back them off.

Also, im not sure if this is common knowledge or not but the "warmup enrichment" and "Cold ignition advance offset" tables share the same coolant temp values. I didnt know this for the longest time. I would tune my Warmup settings and then work on my Cold advance after. With warmup enrichment I would set my last two coolant temp values to 180 and 210. Both values would be set to 0% enrichment.

With my Cold Advance table, I would go much further than 200*. My highest value for coolant temp is 250* with a -3 advance. This lets me pull timing when the coolant gets too hot. Im not sure if this is proper practice but it made sense to me. I guess I could always pull timing via intake temp if needed but I never go above 100* (I maxed at 95* intake temp ON A DYNO during my 2nd pull... The street usually sees ambient or plus 10 tops). My point is that everyone should be careful to watch those two tables because it would mess up my warm up settings because they share the same coolant temp values.

I have been debating some possible over temp strategies, but not implemented them. I agree with what you are saying...

Theoretically a cold engine needs a little more spark advance...

edit: also, I notice you are not using overboost protection. Im sure you'l never have a wastegate fail on you but it might be a good idea to turn it on. Ive used it and tested it (willingly and unwillingly) and it works very well, almost too well.

Yup, need to do that...

Thanks

[Ondonti]

If your coolant temp is up that high, you probably had a failure already and unless its just the radiator fan not turning on in stop and go traffic, you are probably going to ruin your motor no matter what if you keep running it.

I haven't messed with EGO correction since back when you had to go in and modify values in some text document to make it activate. Some features in MS really seem like either the process of running an engine has been overthought (very hard to balance a lot of conflicting tables, find root cause, etc) or MS is just missing something that other systems self learn/adjust.

[Sundance 6g72]

My coolant stays at about 180-200*F depending. I dont know what causes it but its always gone higher while under boost. I think my CLT sensor is just wacko or I have air bubbles or my rad just sucks. Motor has always seemed fine. That discussion is for a different time and place though.

Ill have to do some more reading on the MAT fuel correction table to better understand it.