For Tuners That Don't Understand MBT & Ignition Timing

[@hpa101]

🙌 Enrol today and get $400 off HPA VIP online course package deal: hpcdmy.co/vipek ✅ Want to learn more about ignition and fuel tuning, injector dead time, air-fuel ratios and more? GET 50% off your first HPA EFI tuning course and start learning instantly: hpcdmy.co/igtime Key Terms: TDC = Top Dead Center BTDC = Before Top Dead Center MBT = Maximum Brake Torque or Miminum Best Torque RPM - Revolutions Per Minute ------------------------------------ TIME STAMPS: 0:00 - Common Issue 0:13 - Getting It Wrong 0:22 - The Plan 0:37 - What Is Ignition Timing 0:51 - Combustion Misconception 1:13 - What Is Actually Happening 1:35 - TDC - Top Dead Center 1:53 - BTDC - Before TDC 2:10 - Load Vs RPM 2:24 - Combustion Pressure Graph 3:10 - Compression Begins 3:53 - Peak Cylinder Pressure 4:08 - What Happens When Timing Is Wrong 4:42 - Overly Retarded Ignition Timing 5:23 - Overly Advanced Ignition Timing 6:08 - The Goal Of Ignition Tuning 6:26 - Cylinder Pressure Data 6:44 - Torque Feedback 7:00 - Torque Optimisation/MBT 7:30 - Sweep Test 7:53 - Base Ignition Timing 3D Table 8:19 - Test Cell 8:56 - Dyno Demonstration 10:06 - Results 10:49 - MBT - Maximum Brake Tourque 11:21 - IMPORTANT TO NOTE! 11:38 - Knock/Detonation/Pinging/Pinking 11:57 - Just ONE Cell Optimised Here 12:11 - 1st Ignition Tuning Table Trend 13:04 - 2nd Ignition Tuning Table Trend 13:34 - Low Load 13:50 - High Load 14:02 - Final Notes 14:25 - BUILD.TUNE.DRIVE ------------------------------------ 🏆 Win FREE ECUs, engine components, wiring tools, alignment setups and more. Enter now, no purchase required: hpcdmy.co/giveaway

[@FutureProofPerformance]

Thank you for making this, It's worrying how many people in our profession don't fully grasp some of the underlying physics.

[@jesseb3758]

The knowledge in your head is amazing

[@krusher74]

He's a very clever articulate guy, but this stuff is engine 101 basics.

[@jesseb3758]

@krusher74 well if it's engine basics why are you watching

[@stevesloan6775]

At 4:33mins I was thinking of how you push someone effectively on a swing, via timing the push precisely. Great video.. I’ll be watching this one a few times. 🇦🇺🤜🏼🤛🏼🍀☮️😎

[@Anotherboost]

Great video. It’s always good to leave some room for error. Old story on how a “pro tuner “ kept adding timing on an Acura v6. Then it broke in front of everyone. Guy just walked off.

[@russelloppenheimer3970]

So well explained. Max mechanical advantage at 16-18 degrees after TDC. Easy to imagine pressing down hard on pedals of bicycle. If pedal at top of stroke, or even just after, most of your force is just wasted into bike frame. Push hard too late, you don't get much bang for your foot. We can just imagine that magic spot when pedaling we should press hardest. About 17 degrees past pedal TDC! Then knowing flame propagation for a given fuel density is same at all rpm, clear you need more advance at higher rpm, as well as more advance for less density (light throttle).

[@JethroRose]

excellent description of what is going on and how timing actually generates more power if correct! first time i’ve seen someone ever explain the concept of getting the maximum cylinder pressure to happen at the point of maximum mechanical advantage on the rod/crank. cheers!

[@deancrawford2577]

When tuning for best torque with standalone ecu on NA engines should be fairly straight forward, however when other aspects are thrown into the mix it gets a bit more time consuming, a variable loop type resonance inlet manifold with cvvt cams and compression ratios of 12, 5:1 on pump fuel whilst still trying to reach emissions targets. You got to hand it to OEM's in that regard.

[@rockets4kids]

On the other hand, if you don't care about emissions, this is what allows you to get considerably more power by swapping out only the ECU.

[@jesseyoung4295]

Your presentation was very clear and cincise, and with the visual aids, it helped me visualize what's going on, and how the variables interplay...

[@hpa101]

Perfect! Glad you enjoyed it and cheers for the feedback 🤘 - Taz.

[@Danger_mouse]

13:40 Great info as always. What this part of the video serves to reinforce is the brilliantly clever old centrifugal and vacuum controlled distributor system. Properly set up and adjusted it did all this with no computer using physics 🙂

[@krusher74]

Race cars (poor education) had a lot to answer for, the had many a street driver ditching there vac advance as they thought "race car don't use it, nuts be better!" Imagine how many gallon os gas were waisted in the 60/70/80/90's due to this. Vac cans fight global warming!

[@XX-nw1xg]

This was really great, I didn’t know we could test for MBT that way

[@hpa101]

It's not a feature every dyno has, but it certainly makes the explanation easier to help with understanding it all even if you don't have access to the feature on a dyno or if you're street/track tuning etc 🤘- Taz.

[@teagreen2220]

All different engine configurations will require different timing for maximum power, including the fuel that is used. With the absence of a dyno to test with, I use the amount of airflow through the engine which is scanned while driving. It is important to have an acceleration load on the engine while finding optimal timing for power. Fuel must be spot on during testing and as you get closer you should adjust the fueling. Find highest airflow for each rpm section, such as per each 500 rpm range, throughout the entire usable rpm range by adjusting the timing. When no more airflow is gained you are at best timing for the rpm. You can finally back the timing off a little based on expected fuel and temperature variation. Love your videos!

[@Programentalist]

How do you measure airflow through the engine?

[@teagreen2220]

@@Programentalist the scanner PID of the MAF provides the airflow here.

[@Programentalist]

@@teagreen2220 Ah that makes sense of course. No MAF on my car unfortunately just MAP, so not a viable method for me.

[@teagreen2220]

@@Programentalist a similar approach is to indirectly measure the airflow by measuring the amount of fuel the engine is using. This will tell you how much airflow. You must have the fuel dialed in properly with a wideband O2 sensor for WOT timing adjustment since the narrow band sensors will not work here, they are only good to dial in a stoic air/fuel level, any load on the engine will not use narrow band sensors in a racing application.

[@Programentalist]

@@teagreen2220 Unless you're running closed loop the fuel will be what you set it at, how can that help tuning ignition timing?

[@kylemilligan752]

Observing Best timing for a turbo engine with low turbine inlet pressure differential is very different than street combinations operating at 2.5 to 3:1 intake /exhaust differential. High backpressure combinations love more ignition timing because of the egr effect of exhaust residuals left in the cylinder, but will spark knock in a heartbeat because of the retained heat in the combustion chamber. Making it clear, high turbine inlet pressure will love more timing because of retained inert exhaust gases, but will melt pistons under sustained load

[@StreetDreamzTT]

Really great explanation. Best I've seen.

[@wxmt95]

amazing demonstration with the dyno

[@hpa101]

Glad you enjoyed it, cheers for the comment 🤘 - Taz.

[@johnconnor812]

Awesome video! Easy to understand. Keep them coming

[@hpa101]

Thanks, will do!

[@justinvanburen8259]

Another great video

[@ttt69420]

I just let chatgpt tune my car

[@hpa101]

Is that why you're on KZbin looking up channels that cover tuning and engine building rather than out driving it 😂 - Taz.

[@gregwah]

Got him 😂

[@nicholasprusko9590]

This was a good one.

[@BEYTEK]

As a tuner i never recommend tuning right up to MBT, Less margin for error if loads or batches of fuel are diffrent to the dyno.

[@ben7020]

I think the demonstration was excellent and I'd be happy plotting the timing per test. I guess the safety margin depends on your goals. Example drag racing with known good fuel and maintenance Vs 4wd towing in heat with outback fuel. Cheers As

[@YogisGarage]

keep them coming!

[@MRworldEtIkA]

pro tip yall, never use universal race coils. It'll fried your ECU. had one installed on my own last month, night ride my bike stall i recon it was the fuel pump again (a day ago its socket was burnt), not a minute later it started like normal (i didnt bother checkingit out), 3 weeks after that it stalled again, brought it to my cousin's workshop and found a small portion of the ECU is burnt, the silicone part that is. my guess is that my ECU relying on the OEM coil's resistances, since race coils has lower electrical resistances it doesn't limit how much electricity can be sucked by the coil, so the ECU gave it all and bust a circuit. it was an NA so idk why i bought a race coil

[@notsponsored103]

Why are you blaming the coil though?

[@LuckyFruitRacing]

The ECU should be triggering the coils, not powering them ....

[@MRworldEtIkA]

@@notsponsored103 because I'm dumb

[@MRworldEtIkA]

@@LuckyFruitRacing problem was mine do both

[@LuckyFruitRacing]

@@MRworldEtIkA then you've got a really simple wiring problem

[@guglegugle8075]

Thank you Andre👍👌

[@RonaldReed-ul9du]

As I understand it, an efficient operating Chiller would change everything stated here, or am I missing something?

[@owl2]

Can you automate the dyno timing sweep if you have a DBW pedal?

[@knowbull5hit590]

You my friend, ARE A GENIUS! That would help so much with comparing dyno results at low speed/low throttle

[@hpa101]

The dyno does this for us. You can set the RPM limit and the duration of the run. You don't need DBW 🤘 It might not be a feature on every dyno, but it has been on the Mainline dynos we've had since I've worked here at HPA (2wd roller, 4wd roller and now 4wd hub) - Taz.

[@owl2]

could you put a load cell under the electrode of a spark plug and measure cylinder pressure that way?

[@FutureProofPerformance]

Yes, it has been done that way, head bolts and strain in the block too. There are several research papers out there on the topic if you do some googling. What is tricky is calibrating it and getting reliable results, but for basic tuning it should work ok.

[@hpa101]

Yup! There are such devices for in cylinder pressure monitoring. $$$ for the device, and $$$ for the setup on the vehicle. Some ECUs support such tools directly. Pretty awesome - Taz. www.hpacademy.com/blog/how-modern-ecus-have-become-awesome-entry-to-professional-level-ecus-tech-talk/?

[@bobbyd642]

Are rotaries any different? Obviously there are no knock sensors and premix must play a part.

[@hpa101]

A bit different due to their sensitivity to knock. This is worth a watch and will fill the blanks for you on the rotary front: www.hpacademy.com/blog/tuning-a-rotary-engine-is-different-heres-how/? Hope it helps - Taz.

[@daniel635biturbo]

WOW that's cheating ! I had an aluminium bowl, connected to a copper pipe to hear detonation. And on second gear, kept left foot braking up to max boost pressure, when the bowl started pinging, I lowered the timing 3 degrees 😋 Worked reasonable well up to 400 hp, after that left foot braking is tricky 😂

[@hpa101]

Where there's a will, there's a way! Andre's done plenty of left foot braking for tuning in his time too 😎 - Taz. www.hpacademy.com/previous-webinars/the-key-to-road-tuning-left-foot-braking/?

[@supersayianjim2]

Alright!

[@jockobo]

What happens when the boost pressure is higher 40+ psi? Does the extra amount of fuel slow down combustion?

[@wrighty338]

Sounds like you need to sign up for HPA

[@MRworldEtIkA]

you're talking like the fuel will increase at the same rate as the PSI number without factoring the air density.

[@jockobo]

@@MRworldEtIkA I figured common sense would allow people to understand I'm not talking about a T25.

[@ttt69420]

​@@MRworldEtIkAUm.. you can't increase psi without increasing density linearly. It's an incompressable fluid at these pressures. thats literally the whole point??

[@Stuuutuutu]

Great content as usual, and I have a question. If the fuel is knock limited to which point do you retard the timing ? I mean like the EGT will start to rise as you retard the timing, which is not good either. Heat could damage valves/seats etc. So how do you know when to stop adding boost ? I was told not to go beyond 850°C before turbo. Thanks

[@Creesic]

@@Stuuutuutu well typically you'll tune AFR to an acceptable point on steady state and then after you'll slowly begin to bring up timing until you hit knock. There's a much larger margin of safety than you probably think there is.

[@nickthelebo]

​@Creesic i think what he is asking is on a knock limited fuel with boost at what point do you stop adding boost and retarding timing to stay away from knock in regards to as you pull timing your egts go up because your sending more of the combustion energy out of the exhaust . To that i would say the egts are subjective to where there taken right at the port i dont think it would be unreasonable to see 1100+ degrees on a boosted engine but iv never really had thermocouples in the exhust to even look at My approach would be at the point where the power gainst start to drop off per lb of boost so if you were getting 18 or 20 hp per lb of boost at the start and its down to 9 or 10 per lb of boost you add because your pulling so much timing id say thats the limit ... im not a expert tho

[@Stuuutuutu]

@@nickthelebo Ok thanks for your reply, I see what you mean. I need to tune on the dyno, street tuning is not enough.

[@bluegizmo1983]

Would've been better to show what timing adjustments look like on a regular chassis dyno plot, and how that plot changes as you change the timing to find MBT.

[@GunniGST]

Stop saying 16-18° ATDC. This varies so much and is entirely dependent on the geometry of the engine itself. This angle range does not apply to all engines, it can go below 10° very commonly on modern engines.

[@hpa101]

Then you would see that when tuning such an engine and adjust accordingly using the same principles shown here - Taz.

[@GunniGST]

@@hpa101 you are making what appears to be a universal statement for all engines that ideal peak pressure point is between 16 and 18. No clarification given that this only applies to some engines.

[@hpa101]

That's what you heard, but it isn't what was said. Have another watch. Andre uses the words 'typically' and 'maybe' which cover the bases. He doesn't specfically state that is the same for every and any engine like you are. Hope you enjoyed the video, it's hard to take it all in at once sometimes for sure and there are always exceptions to a 'rule' which is why we don't work to 'rules' with this content and instead work hard to teach an understanding of the topic rather than something you just 'copy and paste'. Tuning doesn't work like that 👍 - Taz.

[@V8Lenny]

​@@GunniGSTmaybe 99% of engines, even diesels.

[@DjCasonDrift]

Bro I just got my first glasses to

[@hpa101]

Hope they make your life a lot easier! Surprising how bad our eyes can get before we really notice - Taz.

[@krusher74]

your mom told you it would make you bilnd!

[@curvs4me]

The people using an ECU and locking timing at 36 degrees etc drive me insane. "You don't want to put a heavy load on the engine at mid rpm range or less" Because the timing is too advanced and you are punching the piston at TDC or sooner with nowhere to use the force. Cap cracking, rod bending, piston melting disaster. Flame burns at x speed for given afr + cylinder pressure regardless of rpm. Higher RPM gives less time for flame front to reach the peak, light it earlier aka more advance. You make the best tutorials! Although your vocabulary might be a bit beyond the avg joe. Something else you can do with light load fixed rpm is leaning out the mixture and finding MBT. Even a high performance forced induction motor can be a bit of a fuel sipper at cruising speed. Good combustion chambers might run something near 16:1 AFR with 50 degrees of advance for MBT at very light load. More tuning time but can save a ton of fuel in drag and drive type stuff.

[@hpa101]

Sorry about the vocab! If there are any words in particular let us know and we can try address them better, otherwise Andre does try make sure any relevant acronyms etc are explained and we do our best to add them to descriptions as well. It's certainly also crazy what people try to do with blanket adjustments. We do all make mistakes and, hopefully, learn from them as we grow into a skill like tuning. All we can do is try help each other when the chance arises, and on the flip side accepting help with some healthy critical thinking skills rather than just blind trust too 😎 - Taz

[@stevenkirk8401]

@@hpa101 Poor cylinder head design (no swirl or quench) also likes higher timing as the efficiency of the burn is less quick.

[@krusher74]

poor education leads to poor choices. They all need do a HP course.