Help Me Tune the TT and get the most out of it...

[DorianL]

Over the next few weeks, I want to do something I have never done before: perfectly tune my engine. I want lovely crips, tan plugs. I want lovely crisp acceleration at mild throttle and all-hell-breaks-loose at WOT.


The combo is:
- 850 Holley - modified for blow through
- Holley strip dominator intake manifold
- AFR 210 Eliminator Heads
- 400 Block
- Mild blower cam
- Forged rotating assy at 8.2:1 (6-inch rods)
- Water/Meth injection
- D1-SC procharger pulleyed for 12PSI
- MSD 6AL2 computer programmable ignition timing with boost retard. Rev limit 6100

In theory such a combination would make 675HP +/-25HP and 600TQ


The plan
I am going to replace all the spark plugs and start with idle and cruise... I am looking for clean plugs. Right now they are quite sooty.

Then work on primary power.

Then WOT.

I want to do as much tuning possilbe on the street and do the final tweaks (tiny jet tweak + ignition timing) at a dyno. But I want this to be 90% done by the time I get to that step.

I have a dual wide band O2 sensor, so that should help.


Where to start
First, I am playing it safe: jetting up on water/meth to the 400-650HP+ nozzle, up from the 250-400HP it was at.

Right now the jets on there are 80/94. I think this is way rich; in fact you can feel some sluggish moments. I think as baseline I will bring it back down to 78/82. Stock is 80/80. The powervalve restriction has been drilled out a whisker. The PV is boost referenced.

All advice welcome...

Stay tuned,

D.

 

[grumpyvette]

if you have a wide band oxygen sensor youll generally want to try to get into the 12.7-13.5 fuel/air ratio band, any leaner tends to get into detonation, any richer tends to get into ignition problems,but supercharged and turbo engines tend to run better on the rich end of that fuel air ratio, and many issues are related to not enough spark energy and heat or incorrect spark timing
but start by getting the ignition advance curve consistent.
then verify your getting both constant fuel pressure and volume, as a drop in either can cause problems.
maintaining a rock solid and consistent fuel delivery is a frequently over looked issue.
youll really be helped by reading thru these links and sub links carefully before you begin, yes IM only too aware most guys will skip or ignore these links, its their loss!
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viewtopic.php?f=55&t=109

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[DorianL]

Ignition first?

Mine programmed by laptop. I lock it out at say 42 degrees advance and "pull or put-back-in" degrees depending on boost, RMP and vacuum at idle and cruise.

42º at any thing above 16" of vac
40º at 10"
38º at 5"
36º at 0psi
34º at 2psi
32º at 4psi
30º at 6psi
28º at 8psi

Distributor is LOCKED at 42º.

OR

This is a basic 1º per pound of boost timing curve .

Locked at 36º , it will always be at 36º unless there is boost then its 1:1 .

...

 

[DorianL]

Hmmm - I guess I am trying to come up with a basic curve for my programmable ignition. I can stretch the curve out at dyno, but in the meantime...

Lock at 36 and pull 0.5 degree per PSI? If I recall correcty at idle high vacuum the engine likes 42 with vacuum advance included.

 

[grumpyvette]

if your getting a true 42 degree ignition advance to work, ID strongly suspect you need a stronger ignition spark as thats a good deal more lead to get the combustion process, to initiate the compressed fuel/air burning than I would think to be ideal, what does your plugs look like (clear photos) whats the gap set at?
a stronger spark will speed up the burn, making a higher percentage of the cylinder pressure useful past tdc.

keep in mind all pressure building in the cylinder BEFORE the crank reaches TDC takes away from and reduces power , as the engines forced to over come the resistance, and most of th useful cylinder pressure builds and starts to bleed off before the piston reaches 30 degrees past tdc as the burn is all but complete by that point, the more robust and powerful the ignition source the less time required to fully ignite and burn the compressed fuel air mix, thats on reason that multi spark ignitions tend to be popular as theres fewer miss fires

 

[Big_G]

Intercooled?...you may not need meth./water injection at your boost levels. Most of the guys running meth. have much higher static compression ratios. The vaporized fuel in the intake tract subtracts a lot of boost-generated heat. Also, don't pull so much timing under boost...your compression ratio is low like mine...I only drop down to 32* at 18-20 lbs. boost (intercooled). Get the best ignition set-up you can afford. Is your fuel pump boost-referenced?...Mandatory.

 

[DorianL]

Nope, not intercooled. Only water meth. (Tho I might swap that around one day... less moving parts.) And yes, the fuel pressure regulator is boost referenced as well.

I want to tune this as safely as possible.

First, my idea is that we agree on and program a generic/safe/reliable ignition curve. (That is why I was indeed, to start, going a bit conservative on the boost retard.)

Then tune the carb + water/meth.

Once that is done... go back to the ignition curve and see if I can "stretch it out" a bit more.

From what I read you are supposed to use the water/meth to tune the A/F. Let's say I want to target 11.0:1 at boost with a max boost 12PSI. I would begin by jetting the carb a bit lean say 12.0:1. Then I would fatten the A/F and tune with progressive water/meth to reach the target 11.0:1. The progressive water/meth would be programmed to start at 3PSI (25% of max PSI) and be full on by 12PSI. Now let's say you hit 10.5:1 by starting at 3PSI and full on 12PSI. You then would use the water/meth controller to lean things out by tweaking the start point and full on point up in the PSI - say start at 5PSI and full on at 15PSI.

See paage 9:
http://www.aemelectronics.com/Images/Pr ... 0-3000.pdf

Back to the ingition.

I can program vacuum advance + boost retard. I am just not sure it is worth programming the vacuum advance in there.

Several people recommened simply stabbing in at (A) 36 or (B) 42 and pulling out advance based on boost for the former or absolute boost for the latter.

(A) In the case of the former, at all RPMs, the MSD would deliver 36 degrees of advance until boost kicks in; then it would start linearly pulling advance out... say 0.5 a degree per PSI. starting at 4 PSI.

(B) For the case of distributor locked at 42 degrees; at high vaccum idle/cruise the ignition would be effectively delivering 42 degrees of advance. As you get on the throttle and the vacuum drops from 12-14 inches of HG to 0 inches of HG. The MSD will pull out 6 degree by the time you hit 0 inches of HG to make 36 degrees of advance. As boost builds, the MSD will pull out linearly more... Just as above: 0.5 a degree per PSI. starting at 4 PSI.

So I guess that is where I am at - if you had to choose a curve from the top two - which would it be?


Hmmmmmmmmmm

 

[mathd]

Do you know meth A/F ratio is 6.4 and not around 11-15:1
If you use 11:1 a/f ratio with a blend of methanol you will be too lean.

The Stoichiometric AFR value is the AFR multiplier. So for (standard, unblended)
gasoline its 14.7. If you set it to 14.7 the LM-2 display will show 14.7 AFR for Lambda
1.0. If you set it to 6.4 (methanol) the LM-2 will show 6.4 AFR for Lambda 1.0.
You can look at Lambda as the percent of richness. If running Lambda 0.85 (12.5 AFR
for gasoline) you are running 15% rich. For methanol 15% rich means 5.44 AFR. That's
where the value of Lambda comes in. If you run blended fuels where you don't know the
stoich value, you look at Lambda and adjust to 10-20% rich, depending where your max
power is. The % value of richness required by an engine (for max power) does change
relatively little (fairly independent of fuel). But if for example you adjust an engine
running methanol to 12.5 AFR, you would be running so lean that it would probably not
even run.

Its best to use lambda if your 02 unit can do that.
also 12:1 is rich to start with(under no boost idle condition) you want to be about 15-20% rich under load/boost(11.8-12.5). and according to the graph grumpy posted above you want around 13-15:1 at idle.
But your right, id start with a conservative ignition timing, tune the a/f ratio(starting by the pilot then the main and last the accell pump) and then id tune the ignition advance.
Because if you tune the ignition advance first and your mixture is rich.. once you lean the mix you can detonate wich is not good(and you need to re-tune your ignitin at this point anyway).

 

[Big_G]

When I get home tonight I'll post a timing map of my combo. It seems safe and no signs of detonation. When I was running this engine with a carb. I pretty much ran a lot of timing with only about 4-6 degrees timing retard. Having the a/f ratio around 11:1 allows you to run aggressive timing.

 

[DorianL]

Thanks!!!!! MUCH Appreciated.

But wait-a-minute that's right!!!!! How do I figure I hit 11.0:1 if my wide band O2 only read gasoline?????

 

[DorianL]

Here's what I am going to go with:

I stab my distributor in a 37 degrees. In cool air I pull 3/4* per PSI starting at 1 PSI. When it gets towards summer I pull 1*. If it is a miserably hot August day at the track I pull 1 1/4. I think if you pull just 1/2 degree and don't start until 4 PSI you are asking for trouble. You may end up there, but i would not start there. i'd start by pulling 1*/PSI starting at initial boost. Remember, if you pull too much timing, no harm. But if your first attempt ends up being not enough timing pulled you could end up with parts in a bucket.

Thanks Greg!!!!

He goes on...

As for the fuel, I think your starting point needs to be much simpler. Test with the meth on right out of the gate. Less chance of going boom if your initial try is not right. Also, to get WOT AFR you will need to be on the track or a dyno. I wouldn't play around on the street with it. Too dangerous and probably too much tire spin to give you anything usefull anyway. Worry about WOT AFR with the water/meth on first. Don't worry about the cruise until you get the WOT right.

Go ahead and set the idle AFR to around 14 using just the 4 corner idle screws but don't worry about LSABs just yet.

Tho don't know yet what he meant by LSAB

 

[DorianL]

Right-

Revved the engine while I was under the hood. A back fire through carb blew the bonnet off and sent the nut (that I handn't threaded far down enough) to meet with my face. Lucky!!!!! Dumb-ass Dorian. I knew it wasn't threaded down far enough! Another mistake i'll never make again. I should be wearing (sun)glasses when working under the hood Just like Fonzie.

(Still hiding my grey hair.)

I pick up the laptop tonight to reprogram the MSD.

 

[Indycars]

Wow, you got lucky! Sure glad you didn't receive any permanent damage!

 

[grumpyvette]

WOW! GLAD IT WAS NOT A SERIOUS INJURY!
good place to point out you should never have
long sleeve shirts
,TIES
loose belts
open containers holding liquids, ESPECIALLY FLAMMABLE LIQUIDS
loose tools
loose fuel line connections
loose electrical connections
flames near batterys
loose fan shrouds
or getting hands near running belt spun accessories
....and yes were all guilty at times!
and having a FIRE EXTINGUISHER, FIRST AID KIT, SUPER GLUE,safety goggles, a CELL PHONE,several 12 ton jack stands and wheel chocks , IDEALLY A WORK HELPER ,handy and most important THINK THINGS THRU, MURFYS A SADISTIC BASTARD!

having a bolt bucket to throw fasteners and small parts and a tool basket ,or rolling tool cart,next to the car, to keep all the tools in the same place , off the car, off the floor and not under foot,is a good idea

I wear safety glasses frequently (LOWES has 2.5 mag bi -focals cheap)

I rarely wear a face shield unless IM porting heads but its a good idea in many more applications

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[DorianL]

Yea - it might actually improve my looks. Still have a headache.

I sometimes wear safety glasses but they get scuffed up quit and become annoying. I should invest in a decent scuff-resistant pair.

This was a close one. I once got a jet of brake fluid shot into my eye when a friend stepped on the brake while I was looking in the MS reservoir... I rushed inside and flushed with water. No permanent damage.

 

[mathd]

Waw, could have hit your eye .

And the brake fluid in the eye, my god bad luck for you.

 

[DorianL]

Wow, this was WAY out of tune. (You don't even want to know - amazing it was even idling.) So glad I got this laptop. $50 former intern, Kevin. Thanks Bro!!!!

Wow, tuning ignition with the laptop is SO much easier. I'm running it locked at 36. -1 degree per PSI.

There is NO WAY to tune this on the road!

 

[grumpyvette]

post all the pictures and info you can, because its bound to help, so many guys think they can tune "BY EAR" or "THE SEAT OF THE PANTS DYNOMETER", its amazing to see what a few real tools designed for the job like INFRARED HEAT GUNS, TIMING LIGHTS,COMPRESSION TESTERS, VACUUM GAUGES, TIMING TAPES,FUEL/AIR SENSORS,etc. can really do to get your engine running correctly

 

[mathd]

its amazing to see what a few real tools designed for the job like INFRARED HEAT GUNS, TIMING LIGHTS,COMPRESSION TESTERS, VACUUM GAUGES, TIMING TAPES,FUEL/AIR SENSORS,etc. can really do to get your engine running correctly

OK Now i just need a good infrared heat guns and i will be set

 

[DorianL]

Funny thing happened to me today - I blew a fuse this morning. I did... not the TT.

The new belt on the supercharger + pulley that I ground back work beautifully. No more slipping that I can tell. Still, after having set the ignition + patched up a tiny vacuum leak, I thought the primaries were a but sluggish. So I decided to jet down from stock 80 to 79.

Gmbl - not good. It started surging annoyingly on cruise as I drove that evening to a Nightwish concert with my son

Anyway, that night, after the concert at 00:30 in my driveway I rejet it back to where it was... the logic being to undo what I did. It improved things a little. Grmbl. Must be a vacuum leak. Idle hot was not great. I reset the float level. (Man I love electric fuel pumps.) Idle is better but still not ideal.

Next morning as I leave for work... @#$%@#$ I have a very hard time getting the now cold @#$%@# engine to start and idle and it surges again. Plus I was reading low vacuum. Grmbl - I must have bumped a vacuum line off. I blow a GINORMOUS fuse (throat still sore from swearing.) and turn around, go home and search all over for a vacuum leak - nada!!!!! ROOOOOAAARRRRR!!!!!

So I decided to remove the supercharger bonnet and as I do... I spot a tiny piece of debris on the air filter gasket. Hmmmmmm... MF!!! I look in the carb and there are little tiny bits of pro-flow air fliter that smoldered and dropped in there - same @#$%@# that burned my face. Sticky!!!!!

Sooooo, I pull out some carb cleaner + compressed air and blast out all the holes. A-HA! One of the holes seems to restrict the air blast. I worked on it a little more and: bingo! Awesome!!!! Better tan I remembered it. When I removed the bonnet to drop the fuel bowl and replace the jets, I must have knocked some tiny debris on an air bleed. Moral of the story: gotta look beyond the undoing what you did but rather what you might have done.

I was surprised to see how much air the centrifugal was blowing in there at idle. Cinching down the carb bonnet significantly smoothed out the idle. What a pleasure to drive!

First things before I tune: go thoroughly through the carb.
Second: go through all the vacuum lines. (I am thinking of using mteal tubing for this? Plus adding a couple more dedicated ports rather than splitting the lines.)

Now for the nice story:
The morning ended quite nicely. I was late and stuck in traffic on the highway to work. And next to me I see a school bus full of kids with a wall of them against the windows giving me waves, devil signs and thumbs ups. I drop it in to N and rev a coupla times to 6000. Mmmmm. That blower bypass valve sounds awesome letting out the compressed air!!!! The drop into 1 and a mild stomp to melt some rubber for a couple of feet... You know the kind of peeling out where you have to make little corrections to the wheel but are moving too slowly to really spin out. :lol: :lol: :lol: The entire school bus goes wild. Poor bus driver he must appreciate me. Anyway I drove off to a bunch of waves and cheers.

We ARE cool!

D

Maybe even a few kid converts over here in Europe!