Hey All!

So I have been working on my car and tuning different gears and have been feeling pretty good about everything so far. Now that I am at the top end for tuning I am nervous about pushing the car past 20 degrees of timing for some reason. I am not getting any knock and everything looks good, even the stock ECU wants to push 23 degrees in the high rpm's. So now I am faced with my lack of experience and would like to share this log with you guys and get your feedback! Oh yeah, please ignore the AFR's. Stupid o2 sensor quit working on me at high loads for some reason. Have a new one on the way but I know the AFR's are good through 7500. Also, how do you get it to post in a better format?


5167, -0.2,1404,100, 60, 00, +7.1, 75.9, +9.4, +4.0, 75.00,1445, >25:1
5491, -0.2,1547,100, 50, 00, +4.7, 93.8,+13.3, +5.8, 75.00,1700, >25:1
5555, +0.0,1529,100, 50, 00, +7.2, 90.2,+12.6, +6.0, 75.00,1533, >25:1
5611, +0.0,1524,100, 80, 00, +7.4, 93.6,+13.9, +0.7, 75.00,1506, >25:1
5698, +0.0,1552,100, 80, 00, +9.0, 91.1,+14.2, +0.9, 75.00,1552, >25:1
5747, +0.0,1577,100, 80, 00, +9.1, 89.3,+14.4, +1.0, 75.00,1453, >25:1
5787, +0.0,1597,100, 80, 00, +10.2, 90.9,+14.6, +0.6, 75.00,1612, >25:1
5847, +0.0,1597,100, 80, 00, +11.0, 92.1,+14.7, -0.6, 75.00,1666, >25:1
5910, +0.0,1577,100, 80, 00, +11.3, 90.9,+14.9, -2.2, 75.00,1543, >25:1
5963, +0.0,1602,100, 80, 00, +13.3, 88.4,+15.0, -2.2, 75.00,1760, >25:1
6038, +0.0,1582,100, 90, 00, +12.3, 93.2,+19.0, -0.8, 75.00,1666, >25:1
6138, +0.0,1592,100, 90, 00, +13.5, 91.2,+19.1, -1.4, 75.00,1562, >25:1
6172, +0.0,1607,100, 90, 00, +14.5, 88.3,+19.1, -2.0, 75.00,1506, >25:1
6242, +0.0,1628,100, 90, 00, +15.5, 88.8,+19.2, -3.9, 75.00,1582, >25:1
6265, +0.0,1607,100, 90, 00, +15.5, 89.1,+19.3, -2.9, 75.00,1497, >25:1
6337, +0.0,1592,100, 90, 00, +15.4, 87.6,+19.5, -3.0, 75.00,1497, >25:1
6410, +0.0,1623,100, 90, 00, +16.1, 89.5,+19.6, -3.3, 75.00,1689, >25:1
6459, +0.0,1618,100, 90, 00, +17.4, 87.6,+19.7, -3.5, 75.00,1524, >25:1
6510, +0.0,1623,100, 90, 00, +17.2, 87.9,+19.9, -5.8, 75.00,1623, >25:1
6548, -0.2,1633,100, 90, 00, +17.5, 91.0,+20.1, -4.4, 75.00,1524, >25:1
6587, -0.2,1639,100, 90, 00, +18.5, 91.2,+20.2, -4.8, 75.00,1572, >25:1
6640, -0.2,1639,100, 90, 00, +18.5, 89.4,+20.3, -5.2, 75.00,1515, >25:1
6720, -0.2,1639,100, 90, 00, +18.5, 91.5,+20.4, -5.6, 75.00,1798, >25:1
6747, +0.0,1644,100, 90, 00, +20.4, 92.8,+20.4, -6.2, 75.00,1552, >25:1
6788, +0.0,1633,100, 90, 00, +20.6, 91.4,+20.5, -6.0, 75.00,1736, >25:1
6844, +0.0,1700,100, 90, 00, +20.5, 94.5,+20.5, -6.0, 75.00,1506, >25:1
6901, -0.2,1677,100, 90, 00, +20.7, 96.2,+20.5, -6.2, 75.00,1700, >25:1
6958, -0.2,1742,100,100, 00, +21.4, 94.9,+20.0, -6.8, 75.00,1655, >25:1
6973, -0.2,1724,100,100, 00, +21.4, 98.0,+20.0, -7.3, 75.00,1533, >25:1
7032, -0.2,1694,100,100, 00, +21.2, 97.0,+20.0, -7.3, 75.00,1644, >25:1
7047, -0.2,1724,100,100, 00, +22.1, 95.6,+20.0, -7.3, 75.00,1689, >25:1
7122, -0.2,1694,100,100, 00, +22.7, 99.0,+20.0, -7.3, 75.00,1811, >25:1
7137, -0.2,1754,100,100, 00, +22.5, 98.3,+20.0, -7.3, 75.00,1602, >25:1
7183, -0.2,1736,100,100, 00, +22.5, 93.0,+20.0, -7.3, 75.00,1572, >25:1
7215, -0.2,1754,100,100, 00, +22.5, 96.2,+20.0, -7.3, 75.00,1623, >25:1
7262, -0.2,1748,100,100, 00, +22.5, 92.0,+20.0, -7.3, 75.00,1582, >25:1

 

If you ask me your timing seems to be about where it should be. Using alot of ignition advance is not the ideal way to go about tuning. Over advancing ignition timing past Maximum Best Timing only increases your cylinder pressures which increase your chance of detonation and killing rings or worse your motor.

Thanks,

Jermaine@turboxs.com

 

Yeah, I wouldn't go past 22 degrees, anything more than that and your risking damage on pump gas. All of this ends up being a balance between your boost and AFR, since it effects the point at which your cylinder/combustion pressures begin to increase, the octane of your fuel obviously also makes a difference. Not sure what your AFR's are, but looking at your injector duties and it seems like you don't have too much headroom left, so I wouldn't attempt to run any more timing than you are at the moment.

I have seen some pretty insane timing on some race gas cars, and a water injected car.. but keep in mind that the higher "octane" slows combustion rate slightly..

Keep in mind, forgetting about the damage that too much timing can do, when you have too much timing, you build pressures in the cylinder that works against the piston, so you actually have that expansion of gases working against your piston, in a world where that wouldn't do damage, you would begin to lose power..

 

Thanks for the feedback guys!
I am looking for new injectors right now as we speak due to the already high duty cycles. I dont want to get an injector that quits on me all of a sudden and causes some major issues.

For gas I am running 2 gallons of 110 octane mixed with 92 octane pump gas. I got a bad tank of gas from Unocal one day and was amazed at how much knock I was getting in a tune that never caused issues before. This is why I started buying the 110 octane stuff to mix with my fill ups. Its not that expensive if you buy in 55 gallon drums. Only adds about $20 / mo to my gas bill, which I can live with.

On the topic of timing I am trying to figure something out. The most ideal place to give spark is at TDC. This would give you the maximum stroke of the bore and provide the greatest power. The thing I dont get though is where exactley is TDC in timing? I figure it has to vary based on engine RPM because from what I understand in adjusting the timing is you are really adjusting to send the command to fire spark at 20 degrees past TDC because by the time the signal is received and activated the piston will have moved from 20 degrees back to TDC. If this is the case then what is TDC spark timing at all the different RPM's?

 

I'm pretty sure you have to take the car's base timing (the mechanical timing) into account too.. You aren't actually firing the spark at TDC, but a few degrees before TDC, when the combustion begins to burn, you are attempting to time the burn and expansion of the gases to occur just at or after TDC so the combustion gases are producing the most expansion on the downstroke, therefore producing the most power. The less advance you use before TDC, the more unburned gases you have on the downstroke and therefore its wasted energy (sometimes going out the tailpipe) Of course, this is an "Optimum" situation since tuning a car so your timing is "Perfect" will produce the most power, however it will also put you at the greatest risk, since bad gas or a shift in octane, or a hot spot, can now increase the burn rate of the combustion gases and you'll end up with cylinder pressures being too great BEFORE TDC where the piston has to work against it and you can break parts, or generate an extreme amount of heat (compressing hot expanding gases) and melt parts.

 

FWIW because the gases burn at a particular rate for a given octane/afr timing for different RPM's is different because the pistons are reaching TDC faster, so if you want to produce the power, you have to "Trigger" (Ignite) the gases a little earlier at higher RPM.. at lower RPM timing is a balance of producing a smooth feeling curve, and not building too much heat due to high pressures (cylinder pressures at peak boost)

 

So what would you consider "Maximum Best Timing"? I assume that it changes based on several factors, including; AFR's, MAF Signal, Boost, RPM, etc.

The approach I am taking right now is to tune out knock, get the AFR's in line, then advance timing while looking for knock and AFR's.

 

Maximum Best Timing or MBT, my view is the point when you advance timing and you stop getting large horsepower gains. The theory is that it is possible to advance timing past MBT and loose horsepower. I haven't seen it. It's hard to tell without having a dyno to tell you what each of degree will do. This is how it usually goes when we are at the point of "MBT", the next degree will give us about 4 whp and the next degree after that is usually a knock count. To me the 4 whp gain isn't worth it. It's only going to create increase cylinder pressures that bring you much closer to detonation.

For the record I have never seen at point where I added Ignition timing and the car stopped making power on pump gas with forced induction. The car may have knocked but it didn't make less power, hell most times it made more power knocking. I have seen the stock ecu do this all on it's own. Until I began to tune 5-6 cars a week I didn't have a true understanding of this comment "It runs great right until it pops". Combustion is a working Force and detonation is a working force the normal combustion process is what you want working on your side.


The idea is to find the balance between AFR, boost pressure and Ignition timing.
Personally I like to see about 11.2 afr at peak torque and then i try to hit about 11.4 to 11.5 at peak power to redline. On shop car at the higher rev ranges, I will go leaner towards redline that usually keeps the horsepower on longer. That's just me and my shop cars. Once my afr's are in line, everything else starts to come together. With afr's at 11.2 my torque is usually low but the increased cylinder pressures aren't exactly worth it to me because peak torque you are always their, repeatedly day after day.

Also excuse my use of the word power, I think for most it's easier to understand the word power than to say torque.

It's all Torque!

T x N
-------- =Horsepower
5252

Jermaine~
www.turboxs.com
301-977-4727

 

Sounds like your methodologies are real similar to mine.. I eluded to the same thing..

 

YES! somebody with 1.) a great post about tuning and 2.) recognizes what they're talking about when saying Power, and Torque.

j.

 

I tuned for <=11.2 AFR's from boost to red line so the AFR's are good. I guess the hard part is figuring out what MBT will be. Espeicially since I am sure that it changes when other variables change. Air Density, altitude, gas octane, etc. Therefore the challenge is getting a tune on the car that can have the flexibility of the stock ECU's 3D maps with a 1D map on the UTEC. Thats the hard part.

 

The item that makes the most difference once a car tuned, I always question octane. When I tune a car i make 3-5 different maps. This allows me to have a little less aggressive map for each condition. The stock ecu maps may be demensional but they aren't demensional enough for it to just switch to a totally different map as it does. The good thing about Mass Air Flow, is that Air Density and Altitude will reflect in the Mass Air Flow readings so they are being compensated for, in the sense of it is all being counted.

 

First off I really want to thank you Jermaine for being so active in this thread!!!

So when I have my known power tune completed how do you go about creating the safe tunes? Do you just take a few degrees from all your maps for different scenarios?

 

The way i typically do it is

Map 1 - Dyno Tuned Peak Power
Map 2 - -1 Timing + Lower Boost
Map 3 - -1 Timing + .3 Fuel + Lower Boost
Map 4 - -2 Timing + .7 Fuel + Lower Boost
Map 5 - Bad Gas or Race Gas Depending the Customers Tuning Session

Thanks,
Jermaine~

 

I usually back off on the boost in the map, a little bit on the timing where you get peak torque.. if the map is tuned well, you should find your lower boost levels in a different group of load sites anyway.. but you can then have purpose built maps which are a huge advantage.. nobody wants to road race with a drag map.. ya know?

On my car, I have three distinct maps, a cruise map with basically lame timing, a performance map with much higher boost, more aggressive timing, and slightly leaner, and my "oh my god" map, which will almost guarantee the destruction of my motor if I run pump gas..