Put some plates on my project car recently to do some tuning. Very fun to drive .

Took a couple vids of some part throttle pulls. Turbo seems to spool somewhere around 3000. It's a BW 84-75 IIRC. Transmission is a T56. Haven't taken it to WOT yet since tune is pretty rough still.




Engine bay still could use some cleanup but I really wanted to start the tuning process. Been having trouble getting it to idle but I'm sure I'll figure it out sooner or later.

 

Nice man. I like it.

 

Nice! What did you have to do to adapt the T56?

 

Very nice, man.

 

Oh BTW, contrary to popular belief, a V6 can have enough torque to use 6th. The 4.11 gears definitely help though. More on the conversion later. I basically modified an LT1 SFI bellhousing and used a 3.4L clutch/flywheel setup with an upgraded clutch of course. Pilot bushing is the same as a 3.4L bushing but twice as long and I'm using a HTOB.

 

Nice.

Sounds pretty good, a bit lazy but great for beginning to tune.

 

Hey six_shooter do you have any suggestions for getting this thing to idle? I've played with the IAC vs coolant temp settings to add more air, and raising the desired idle speed a bit but it won't stay running when warm. When its cold it will idle for a few minutes.

 

What code are you running?

 

I've tried code59 and nAst1, code59 idles slightly longer at a stop but only by a couple seconds maybe. I'm hoping to stick with nAst1 in the future for the spark-cut limiters especially.

 

Robertistaar may be able to help with nAst1

I run $59. Works well for me.

 

nAst1 is a custom code, that Robert Isaar has developed based on $A1.

What are you IAC counts?

Does holding the throttle open slightly allow it to "idle"?

 

If I hold the throttle open it will stay running yes. However if I punch the throttle it stumbles before catching. I've tried everything from 20-35 steps when warm to keep it idling but the only thing it seems to achieve is a high idle that still won't hold at a stop for more than a few seconds. I have to give it gas every few seconds to prevent stalling.

$59 has pretty much the same issue.

 

Just though I'd ask six_shooter since IIRC he has experience tuning with large injectors. Not sure if robertisaar does.

My injectors are 52 lb/hr btw

 

You need to identify what is lacking (or too much) when it wants to stall, fuel air or spark.

These are some general ideas I use when dialing in a new tune:

Ok, to start with, and you will change this later, (so before anyone jumps at me because they think I'm "doing it wrong" can just STFU) open the throttle plate a little, don't worry so much about the IAC steps right now, but it's good that you're trying to at least keep an eye them. In the end you will want to end up with warm idle steps in the 35 to 45 step area.
Opening the throttle a little, will take some of the "load" off the IAC to keep the engine running.

You will also need to look at your stall saver settings. IIRC I had to raise some of the parameters higher in the RPM, since the V6 and I6 just don't have as much rotating weight to keep the engine spinning (think flywheel effect), so the stall saver needs to become active a little higher than what is likely set in the bin.
It's been a while since I played with mine, but I know I had to raise the DFCO disable settings, that is, to make the DFCO turn off at a higher RPM, as the RPM was coming down to re-enable fuel.

What is your idle AFR? At the start, I tend to run a richer AFR than you will want to in the end, just to keep the engine idling. After you get some of the other parameters and VE table areas more dialed in, you can come back to idle, and get that squared away. IIRC when I was first tuning my I6 with $59, I would have an AFR of around 13.5 to 14 at idle, as I was getting things dialed in and could then reduce idle fuel delivery. If I can I shoot for a 14:1 AFR with a stable, or fairly stable idle, before going on. Sometimes it's just easier to make it slightly richer, and come back to it. Just keep an eye on this and don't make it too rich, or you'll be oiling down cylinders and replacing oil often.

The next thing is spark advance. I found in my case the box stock settings for SA were low and would cause the engine to stumble a little. Adding some SA at idle really helped keep it idling and smooth it out. IIRC, I'm around 17* BTDC at idle, I've had it as high as 30* in testing, but saw no improvement after about 19 or 20 * of idle SA.

If I think of anything else I went through when I was dialing mine in, I'll post it up.

 

youre getting cantankerous in your old age

come at me bro!!!


/hijack

 

Hes got to have a wideband on there. Id be curious to see what the afr does under the stuble. Is he getting too much fuel, not enough fuel, too much spark, too little spark.


Do you have a datalogg you could post up for all of us??? I probly cant really help as im a newb. But im sure sixshooter or joe could point you in the right direction.

 

Ya I've got a wideband on and have been datalogging. By adjusting the throttle stop I finally got somewhat of an idle. Low MAP (25-35ish) is pretty rich right now but for cruising the rest of the table is somewhere around 14:1. Under boost it's around 10:1 right now. Keep in mind this is still a very rough tune.

There's some misfiring going on right now at low load and sometimes under boost but not at part throttle. I'm not really sure what's up with that but I've gone through all the ignition components already and they check out. Could it be that the injector pulsewidths are just too short for the ECM and the injectors aren't firing sometimes?

I'll try to get around to posting a datalog and my current .bin later tonight.

Oh and whenever it stumbles the wideband swings full lean. Pretty much only when punching the throttle right at idle.

 

Have you verified spark advance between what the ECM is commanding and what is being seen at the crank? (sorry I should have asked this earlier).

I know I had to make some adjustments to one of the bias tables to get what is in the SA table to line up with timing relative to crank, it was off by a couple degrees, retarded IIRC. (this is with $59 FWIW).

From what you're posting I'd be looking at spark advance, verifying it, at idle and above. I know it's hard to verify under any real load without a dyno, but even some revving in neutral, and verifying with what is being commanded will give some indication.

Yes Joe, I am cantankerous, but not just in my old age. lol

 

Try your best to get the proper injector compensation values, it will make a world of difference. Check the injector PW in the data log during idle. You will likely find that it is getting very small. Small enough that the injectors never open, which is causing the engine to stall.

Having the proper injector compensation values will go a long why to correcting this.

It also sounds like you need to reduce the volume of AE.

RBob.

 

The injector base pulse constant is the only injector value I've played with. It's currently set at what robertisaar recommended, which is 81.

Also I'm going to add that I've since gotten the part-throttle/idle AFRs down to the 14-15:1 area and the misfire is very prominent now in those areas. I'm almost positive the misfire is fuel-related since it runs smoother when it's rich.

Edit: I was also considering lowering fuel pressure to see if that helps with the misfire. IIRC it's currently set at 55 psi with the engine off, and has a 1:1 vacuum/boost reference.

 

The datastream shows a BPW value; not sure if that's what you were referring to as injector PW. In my case it seems to be in the low 1.xx around idle speeds.

In any case I'm posting up my WIP bin w/log and def. files for anyone to check out if they feel like helping me . If you go through the log you will see areas where the wideband reading swings quickly between 13-14:1 and 15-16:1. That's when it's misfiring at light throttle. I guess it's better than wasting precious 94 octane .

 

Rbob was talking about the injector voltage compensation(sometimes called offset?) tables. its good to have a datasheet for the injectors you are using to interpolate that table.

 

Ok it's gotten better now but driveability is still pretty bad. It's annoying how much the IAC settings affect everything... Adjusting the AE vs pulse table got rid of the sudden-throttle-misfiring so WOT performance is actually very good now, but I've still got misfiring at idle especially. Sometimes when coming to a stop in neutral the car struggles to stay running, but then when the car is stopped the idle sounds normal. In fact, it seems to like idling best at a 12:1 AFR.

I was expecting this turbo to start making boost at 3000, but I'm actually impressed that its building boost around 2500 and makes full boost around 3000. It's supposed to be comparable to a GT35 (journal bearing) and it has the 0.91 A/R T4 twin scroll exhaust housing on it right now.

Because of all the driveability problems I think I'm just going to finish tuning WOT and take the plates off. I may go megasquirt but haven't decided yet.

 

What boost levels are you pushing right now?? Intake temp rise under a good WOT pull? AFRs under boost?? Just woundering.

MS would be good. Although the longer Ive had $59 the more I like it. Never had any real issues that wernt my fault

 

Wastegate pressure for now at around 8 lbs. haven't seen IATs go above 105*F yet. I'm going to try adding some timing at low MAP/RPM and see if that makes any difference for part throttle. AFRs under boost are currently between 9.9 and 10.5 under boost. I'm working on getting those to 11.5

 

What size injectors you running fasteddi? I think I'm going to try lowering my fuel pressure as well. I don't think I really NEED the extra fuel from 55psi vs. 45 psi, not to mention lower fuel pressure I'm hoping will make everything a bit easier to dial in.

 

I have 48Lbs injectors on my set up from southbay. When I first boosted the car I had 28lbs injectors, but that only lasted so long before I maxed them out then had to jack the fuel pressure to make up for it. What size injectors are you running at the moment????

Yea you need to lean that puppy out a tad. Im amazed that you arent seeing some false KR from the overy rich condition under boost. Dont get me wrong though, 10.5 is better then 13.5 but its gonna wash down those cylinders.

My AFR guage displays 10.2afr at the lowest. So if I was see 10.2 on there whos to say its not really 8.2afr or 9.2afr. You see where im going with that.

I dial in 11.0-11.5 for my desired boost level weather it be 8,9,or 10psi. I have alky injection though which changes the afr reading a tad from what the gas is really burning at. You aiming at 11.5 is a good thing as I pushed the boundrys last year aiming for 12.0-12.5 which was too risky.

I wont lie though by base tune was pretty good though from code59. So I didnt have to mess with it much to get the fueling where I wanted it under boost.

Sounds like you IAT's are in check. I remember when I just had just a intercooler, my IAC's were way to freaking high all the time. 30-60 degree rise in a 1/4 mile pull. Were talking 150-160* temps sometimes at the end of the track. Thats why I went alky injection to keep that crap down. But your turbo is a helll of alot better then what I had last year.

I will say that im excited to see your post. I really like seeing other turbo v6's thirdgens.

 

Just want to point out that, according to Rbob's research, stall saver actually induces a stall. Turning it off and adding spark in the low rpm areas of the spark table will help prevent stalls.

 

Then why is it called "stall saver"?

In every case where I've adjusted settings of stall saver in a way that would make sense, the stalling has improved, as in, stalling became less and less frequent, until it didn't happen.

Stall saver already adds timing when it's induced, so there's no need to artificially do this.

 

hmm..... if invoking the stall saver caused stalls to be more likely.... i would have to assume more air is being added, but fuel is not?

 

Could be, I know in many cases the IAC is opened at the same time Stall Saver is invoked, I just don't recall off hand if it's because of stall saver.

I have found in many cases that the fuel enable from DFCO has a larger bearing on whether an engine will stall over anything else. Especially if an engine returns to idle very quickly, the enable RPM needs to be raised to ensure that the fuel will be delivered at a point that will actually cause an engine to catch itself.

 

I'm going off Rbob's research, keep in mind this was from a number of years ago but IIRC the code pulls spark at a certain point inducing stall. Apparently it's named wrong... I don't know how this is handled in $59 though as it's custom code. All the OEM programs cut spark.

 

Not from what I've seen, since there's usually a "Stall saver spark adder" that I've seen in just about every code I've worked with.

 

My injectors are 52 lb @ 44.5 psi. It's not too warm here yet which helps explain my low IATs. I've got a meth kit to finish installing when I go for more boost. All I really have left is to mount the pump and run the lines. I've already got the bung in the intake pipe. The only false knock I've seen is when I first go into PE at lowish rpms. My wideband reads from 7-22 so 9.x isn't out of its range.

In any case I need to check out spark advance at idle because there are times when it idles smooth and times when it doesn't. Happens sometimes cold or warm.

 

52lbs injectors will last you awhile hp wise. I will say its a tad harder IMO to tune large injectors. Mainly it just harder to get a solid afr at idle.She might move arround a little.
Took me a little longer to tune in the 48lbs compared to the smaller 28's.

 

My dealings with stall saver seemed more like if the idle RPM was under commanded for a certain amount of time, and the underspeed advance correction wasn't helping, the IAC would basically go wide open to try and save the car from stalling. That's with $A1

IMO, one of the most annoying things to fight with a tune.


There are other errors (like high MAP for xxx seconds w/low TPS) that will stall the car on purpose, those are easy to fix though.

 

It is dangerous to generalize how the GM code works across the different masks. In the TPI $8D & $6E masks, the stall saver activates the ET/BYPASS line putting the spark advance at the distributor base setting. This may work OK for a stock engine, but is an instant stall on a modified engine.

Many of the TBI ECMs, stall saver yanks the IAC open. Along with the added fuel for when the IAC opens.

I did a quick look at $58, appears to both a SA parameter that is used along with some IAC action. All of which is tied to the P/S pressure switch. Which makes sense since the original application for $58 (and the forerunner mask) was little 1.8 & 2.0 L 4-bangers.

RBob.

 

Well I think I have a smooth idle now; retarded the spark about 5-6* at idle and now it hasn't stalled since. I thought the spark would be fine since I more or less copied the tables from my Fiero tune. Could the cam or injector spray pattern significantly affect this?

 

cam will do it, considering how well 3x00s respond to cam changes.

 

Idle is fairly stable now but any lower than 1200 and it stalls pretty quickly. Also doesn't like to stay idling at an AFR above 14.x I think I'll leave it at that for a while and focus on the VE tables now. Tried enabling closed-loop again and it still causes constant misfiring, so I'll just leave it in open-loop.

 

Ive never ran mine in closed loop yet. But I dont DD it so I never saw a point in doing that. Mine idles at 14.5 at the highest. Any higher and she tends to hunt exspecially on a 90* day.

 

Ya this isn't a DD really but I'm DDing it while I get the tune nice and solid. I also want to do some upgrades to my actual DD while it's uninsured.

 

Took some better pics now that the sun is out.




Also installed a Subaru STI seat. WOW - what a difference. Car just feels sooooo much better in the corners now! And it was very simple to install. The bolt holes in the seats are the same distance front-rear as the 3rd gen rails, just about 4" farther apart left-right. I'll get the passenger seat in too once I have a bit of free time.

 

Holy crap what kind of paint did you use on the pipes again!?!? It's holding !!

I'll be tunning my 3.9 soon, hopefully can offer some insight.

 

Looking good bud. You going to take it to the strip and see what it can do?? Id like to see what it can. Im stuck on my 3.1L engine for now. But in case I ever go larger, i like to learn from you guys so I can go faster.

 

It's just VHT flat black paint on the the pre-turbo exhaust and silver on the downpipe. Hasn't burnt off yet!

Hopefully going to get this to the strip on Sunday (1/16th mile for now) but have to swap out the rear end since I shredded the ring gear the other day . So probably just going to have a 3.23 gearset for that day. 100 km/h in 1st FTW!

 

only need to shift once?

 

Ya when I run my Fiero there I'm shifting into 3rd about 3/4 down the track and finish at about 65 MPH (about 105 km/h). 2nd gear with the T56 and 3.23s allows me to go to 144 km/h so that will be all I need I think.

 

 

Nice carnage!