TUNE VS POWER! HOW MUCH TIMING SHOULD I RUN ON MY TURBO MOTOR? WHAT A/F RATIO SHOULD I RUN (9:1?)
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- čas přidán 23. 07. 2024
- HOW MUCH POWER IS TIMING WORTH ON MY TURBO MOTOR? WHAT IS THE BEST A/F RATIO? WILL MY NA MOTOR RUN A 9:1 AF? WHAT HAPPENS IF MY TUNE IS OFF? WILL MY MOTOR STILL RUN? CHECK OUT THIS SERIES OF TESTS RUN ON AN NA 383 SMALL BLOCK CHEVY, WHERE WE (ACTUALLY THIS TEST WAS RUN FROM ENGINE MASTERS-THNX DAVID FREIBURGER) VARIED THE A/F RATIO BY MORE THAN 3 FULL POINTS, FROM 12.5:1 DOWN TO A VERY RICH TO 9.1:1. WHAT HAPPENED TO THE POWER? WE ALSO TESTED IGNITION TIMING ON THE SMALL BLOCK, FROM 36 DEGREES (WHERE IT MADE BEST POWER) DOWN TO JUST 11 DEGREES!
I ALSO INCLDED TESTING RUN AT VARIOUS TIMING LEVELS ON A TURBO 4.8L! HOW MUCH TIMING IS NOT ENOUGH AND HOW MUCH IS TOO MUCH? - Auta a dopravní prostředky
Thanks for the information Richard.
Love these kinds of tests!! Good job!! So surprised
Boost change on the 4.8 turbo motor was across the rpm range going to 24°, but the timing was only above 4500 rpm. That tells me it’s something other than timing!
Thanks for the recaps, the places where you stop and put data. Thanks!
I think a bit of ex still burning is helping spin the turbo, keep it hot. With a diesel retarted injection timing defenetly helps spool a bigger turbo as compared to advanced although usually they make more power addvanced
Agreed, I was thinking there was a little more heat energy driving the turbine with the lower timing levels.
The Honda guys go extreme retard to spool big turbos, a lot of fuel still burning out the exhaust.
more timing = less enthalpy available to spin the turbo. more of the heat energy from the fuel is converted to work (more hp) and more fuel energy would be transferred to the piston and cooling system. this would show up as less boost, so your data does make sense. having a turbine inlet thermocouple would have shown this too.
I agree with Reed, but also in play is the size of the turbo. You went with a 76mm turbo which is on the large size so when more energy is converted to Hp/Tq (or RME - Rotational Mechanical Energy). This is why I wonder why no one in the Hot Rod world has experimented with a venturi style nozzle at the inlet of the hot side of turbos to make the most of the available ideal gas properties.
I agree completely Reed, to prove this simply read the exhaust temp before the turbine and you will see as timing is increased, exhaust temps fall
Love your vids man!!! You’re today’s hot rodding figure for sure 😁
Thanks 😁
You are correct about other issues. I have seen many a vacuum leak cause headaches. I have also seen cams lobes go flat which really messes people up.
Richard is the man, great stuff. I’ve seen this tuning on the street and I “intuitively” believed it to be the acceleration rate of the engine increasing/better efficiency. The other possibility would be lower EGTs creating less boost. It would be interesting to see this with EGT, IAT, & airflow data.
Assuming the accel rate was the same for both tests maybe this supports EGT variation being the driver?
well .. boost is just a measure of restriction to flow... with the added timing, the engine flows better thus lowering the observed boost.
Just like what happens when you added timing at idle, and then the rpm gets higher and makes more vacuum.
Yet another great, informative video! I’d really like to see that 383 on twin eBay turbos, some guys like to keep their classics powered by old school setups I.e. sbc 383 but add some cheap turbos
love that you included a sound clip 😂👌🏽
I never thought learning can be this much fun.
Black holes,FTW now that one made me laugh 😂
Best voiceover "Waaaaaah waahhhh wahhhhhhh"
I want the Black Hole tune! I wonder where the Event Horizon is in the exhaust tract ?
The fuel releases a given amount of heat. The timing on a turbo engine effectively determines how much of the heat is turned into mechanical work by the engine and how much heat is sent out the exhaust as waste energy the turbo recovers.
The fuel releases the heat? You mean the spark/combustion? Optimized timing allows for the best possible combustion pressure to be applied to the piston
@@jacobburskey3044 I’m referring specifically to the fact BTU/lb of fuel doesn’t change based on ignition timing. 1 milligram of fuel releases the same amount of energy regardless of ignition timing. The ignition timing is how we optimize the release of that energy to expand the gases in the chamber at the appropriate time to create maximum torque. Everything that doesn’t expand the gases or penetrate the cylinder wall into the cooling system or penetrate the piston crown to heat the oil, goes out the exhaust. The later we fire the ignition the more energy is released as waste thru the exhaust
@@justRD1 yes to all but that last statement, which isnt always true. its engine dependent for what timing is optimal and if happen to start your timing adjustments past mbt as you lower timing youll gain power production.
@@jacobburskey3044 if you’re beyond mbt then you’re working against the momentum of the rest of the Powertrain and loosing substantial power as well as risking engine damage. I didn’t bother bringing such a scenario up because you should never be there.
i wish i could have your life
horsepower, dyno, educate others…
Good life man! Good life!!
Boost drop rpm from timing is an effect of back pressure in the exhaust. Containing more of the combustion by advancing timing as you said increases efficiency and useful work while less heat/work goes out the exhaust. Less heat in the exhaust means less gas expansion means less back pressure which in turn lowers boost pressure.
That’s at least what I feel is happening here.
Richard, I like the subtle changes you made to the video format. 👍
Glad you liked it! (I assume the recaps)
Yes, they were a nice addition. Or at least, I think so.
I’m all about that black hole tune.
Thanks so much for doing this detail on the 383. I have one in my boat that's similar but not same. It has Dart iron heads so maybe it gets a little less advance.
It has 10.3:1 compression and probably a milder cam.
I have it propped to get 5100 rpm, maybe I should try a little less ratio to let it spin to 5400.
It's not been dyno'd but maybe it can be dyno tuned this winter if I can get it out of the boat for a checkup.
G'day Richard. The reason for the boost drop as the ignition timing is advanced is because the temperature of the air at the point of ignition is lower, combustion & exhaust gas temperture is lower, & the resulting boost is lower.
As Chris Greenup says, fuel has a calorific value, which is independant of the initial temp of the compressed air/fuel in the cylinder. Air temp raises with compression ratio, but since the air/fuel mixture is ignited earlier in the compression stroke, the air/fuel temp is lower. That lower ignition point temperature leads to lower exhaust gas temperature. The turbo is a device that uses heat energy & converts it to kinetic enery. The lower the heat energy, the lower the kinetic energy. The lower kinetic energy leads to lower boost pressure.
BTW, you could try a test where the ignition fires every 360 degrees vs 720 degrees. I read somewhere that motorcycle engines used to get more power from a turbo install because the ignition fired on the compression & exhaust strokes. The Ex stroke firing raises the EGT & boost. It was probably an article by Kevin Cameron at Cycle magazine - he knows his stuff, so it might work.
Thanks for a great question - it's an oldie, but a goodie.
Andrew
Additional timing advance lowers EGT's that drops the turbine drive power so boost goes down.
Yes a vacuum small vacuum leak can definitely throw you off. Pretty annoying
Maybe it's something to do with exhaust temp, on the turbo set up. When they don't have enough timing some of the air fuel escapes out the exhaust unburned. Maybe it's still creating pressure in the exhaust after the exhaust valve closes causing it to turn the turbo just slightly harder than when it has enough timing to get it all burned in the firing chamber ?
Just a guess........
That's my thought, and to expand on it, it would have been interesting to measure exhaust pressure before the turbo and overlay those results on the test. I think the late ignition shifts the combustion process somewhat into the exhaust event.
@@yarrdayarrdayarrda
That's kinda what I'm thinking.
Its very slight. But I think that's what might be going on
Thats usually how a two step ignition gets basketball sized turbos to light on a sportbike engine. It cuts ignition completely over an Rpm threshold and retards ignition timing to 0 to -* degrees so the unburned charges ignite in the pipe. Really delayed ignition hits a turbine hard with the high temp and energy of the fuel charge that didnt do any work in the engine.
About the same as I was thinking. It acts like a mild antilag, that use a bit more of the energy in the exhaust for spooling the turbo, and a bit less to make power to the crank.
Agreed the timing dropped the boost curve. With more timing in the engine it became slightly more efficient at producing power therefore the boost dropped slightly. It does make sense.
The change in boost in my opinion is from some other factor than timing. Timing may play some part, but in particular for the 24 degree run, you said you only changed the timing after peak torque. If that's the case, it should overlay the 22 degree boost curve until the point that you added the full 24 degree and then diverge. The fact that it is offset for the whole rpm sweep leads me to believe there is some other factor involved besides timing.
I noticed that, too.
I like all of your videos , very informative. on the question of boost loss as efficiency goes up , What about the possibility of the force of the actual unburnt fuel particulates on the turbine on the hot side. is it possible this can have a actual pressure effect on the turbine? As the fuel air mixture is more efficiently burnt . less particulates are left . a water turbine is way more efficient than one pressurized by air . it would be interesting to see the actual turbine speed or even better FORCE in the different circumstances . Please tell me what you think
I know I'm not telling you, Richard, but commenting as asked anyways. When the timing changes, meaning your actually timing the flame front propagation to engage the piston (and thus rotating assembly) you are taking the energy from the combustion mixture and you can either let that expansion or work exit the exhaust with low timing where it will drive the turbine, or you can light that mixture off faster (more timing advance) and properly time it so the expansion is spending more time pushing the piston down in the cylinder and converting it into work at the crank. Tuning 101
Exactly. I watch a lot of Evans Performance tuning videos, and he always starts super conservative on the timing numbers, like 5 degrees. You can see the boost drop with each incremental timing bump. It's funny to add 3 degrees of timing and lose power because the boost dropped by 4psi, lol. Good stuff.
I can say, improper jetting with the wrong power valve will make a carburated car act funny at crusing speeds
Don't know why there was the boost drop.
Do know boost is good, timing makes boost better (till it doesn't lol)
Less timing pumps heat into the turbo and that pumps the presser up. As timing was advanced the heat was kept in the engine.
more of the combustion energy was captured in the cylinder which caused less velocity in the exhaust resulting in less boost
As simply as i can put down what i think….
Less timing leaves an incomplete burn. ie the there is more expansion still happening during the valve overlap period than at earlier/more efficient timing levels.
The incoming pressure is in essence running into reversion prone pressure Making more overall pressure.
Right on
My assumption on the boost drop would be due to allowing more of the combustion reaction to happen in the cylinder by advancing the timing thus creating less back pressure in the exhaust.
It's like launch control/2 steps where it retards the heck out of the ignition to get boost earlier on the line. As said, the heat from the ignition gets the turbo spooling earlier and in the case slightly more
a lot of the time 2 step doesn't build boost ...
To SIMPLY answer the boost question: kinetic energy reduces over time and distance so the later you can make the moment of combustion, the more energy will transfer into turbine.
I would have thought that the change in boost from different timing was due to less exhaust pressure when ignition happens earlier
Boost is a measure of "restriction", not necessarily boost, is what I was taught. When its happy, hp is the product of boost and that's the number that matters. Another great video. Ty sir!!
Under about 10 to 1 afr (Lambda 0.65) it should smoke. Its combination specific but youll see nitrous guys that smoke from the second they start. The more oxygenated the fuel, usually the lower the lambda of smoke point and lower lambda of peak power. Smoke, rich smoke, is particulate carbon liberated in the combustion event in a deprivation of oxygen. Its so O2 deprived it doesnt even form carbon monoxide. Methanol is really unlikely to smoke basically ever because you have to break the CO covalent bond and have enough hydrogen saturation to bond the free oxygen before it finds another carbon. You would also be at lambda about 0.35 to actually cause the necessary conditions to allow smoke. The energy of the system will actually favor formation 2 moles of CO as opposed to 1 mole of CO2 and one mole of C. Jennifer Szabo wrote an article describing methanol lambda in different situation and I think that smoke, as in particulate carbon, is really unlikely from a methanol engine. It is so rich that it probably wont run.
My take on lower boost pressure would be increased exhaust gas velocity from the increased dynamic compression force due to the increased ignition timing creating improved exhaust scavaging.........the higher in RPM the better this gets thus the power response.
Looks like you would need to see intake temps, but it looks like combustion temps were higher due to timing increase.
N/a motors have the same effect but measured as vacuum @ part throttle. I think more advance = more thermal efficiency, this effect the exhaust scavaging so when the intake opens there is less air pressure in the combustion chamber....
scavenging isnt important until wot anyway but with a big cam more vacuum definitely helps keep intake charge from blowing out exhaust at low rpm and screwing with 02 sensors on efi
Think it’s definitely efficiency. Boost is a restriction…if the engine is more efficient, it can use more air, meaning less restriction
The lower timing created more exhaust heat, which raised the boost slightly. The LY6 im tuning boost crept really bad. I only had 10 degrees in in at the time. With no other changes besides timing, the boost stopped creeping. Just my humble opinion.
I got rid of the motor but there was one I couldn't cure the backfire through carb could have flat cam lobe Been adjusted the rockers but never went deeper than that
I think the lower timing is spitting more fire out of the exhaust and creating higher temp and a higher volume of flow spinning the turbo harder.
Is there any difference between sb1 angle plug heads and strait plug?
Efficiency is the reason
I reckon More timing creates less energy after the exhaust valve which equals less drive pressure causing a higher differential pressure between the intake side and the exhaust side causing more flow through which equals less boost. If it had a electronic boost controller on it to run the same boost by closing the wastegate it would produce more power again
Could the decrease in boost pressure be caused by an increase in VE due to the timing change?
Can we get a timing sweep test at higher boost levels to see MBT on good gas? I know most of us slops keep the timing in the 12-14° range above 20psi, but I would like to see what the engine really wants.
we ran 18 degrees with 29 psi on the big bang motors
The heat is being used to push the pistons down instead of driving the turbo??
I’d agree it’s all about the turbo 4.8 running most efficiently at 24* timing
Yeah, I wish he would have run it at more than 6# of boost. I wanna see what it wants at 30#, lol.
What’s your thoughts on timing at low rpm vs high rpm on stock motor base timing of 4 degrees to 32 btdc pulling 20 degrees up top is going to be just right but 20 degrees down low is going to put ignition after 15atdc so do you factor a percentage or what do you do
The engine is gonna want what it wants. Only way to know what it wants is a Dyno. But generally speaking the more cam duration you have the more initial it's gonna want
That's why all these thumpr cammed cars are slow. They need a shit ton of initial timing then they run pretty good for a noise maker
I miss the tune I had 12 deg of time of my twin turbo at 14 ib of boost I was on vp c85 I think I need more timing lime 20 deg I think it would of made move power
Were you recording knock during the boosted timing tests? If so, did you see any and at what timing/boost levels?
we don't run knock sensors-it's not a factory ecu
More spark advance, engine gets a little more efficient releasing energy in the cylinder, so there's less energy in the exhaust to drive the turbine.
I wanna hear the sbc run with the timing and air/fuel way off at the same time
I recently decided to turbo charge my car and was also worried about running it untuned, it’s running great almost 5k miles on the turbo set up and it’s still healthy, a lot of people said it wouldn’t work but as long as you keep on the factory sensors connected the stock ecu will do it’s thing
2000 Lexus gs300 2jzge turbo with 250k miles 🦾still factory auto
terrible idea
@@richardholdener1727 🤣 it works for now until I get a proper ECU but the stock ecu can compensate for 10-11psi for it hits fuel cut, as for timing it’s anywhere from 20-38 , AFR at idle 14.4 to 15 & 12s WOT, low boost 8psi
hey Richard I have a 10 to1 347 small block Ford with a gt45 turbo I'm going to run 8 lb of boost on 93 octane it's 30° too much timing? and if so what would you recommend
PROBABLY TOO MUCH
The old saying: Time for torque, Jet for Power.
An updated take: Adjust timing for maximum mechanical advantage (think maximum cylinder pressure vs crankshaft position), adjust fuel for knock/temperature control.
Timing for force/power, fueling for safety. Seems simple enough.
The N/A overlays points out that there is benefit to controllable rising timing curve rather than those silly springs we use in a distributor. I love being able to dyno tune with a modern ignition controller or EFI where I can tailor the ignition curve for best results throughout the run.
If the timing changed the boost, the boost would have been the same up to 4500 as the 22* run. If you ran these pulls back to back I’m guessing the spring on the gate was getting hotter and hotter changing its spring rate. I see this on my fuel pressure regulator as underhood temps go up the fuel pressure goes down.
More boost at lower timing due to lighting the fire later, peak cylinder pressure is happening too late leaving more residual cylinder pressure as the exhaust valve opens…
That makes me think it needs a wider lobe center to open the exhaust valves earlier.
Wish you would have showed what the power did when you got up in the 13.2/1 range…
My TBI runs at 14.7:1 when the engine gets to operating temperature. When the engine is cold, a out 120 and lower it runs from 13:1 down to 11:1. It seems to have quite a bit more power when it runs rich like that. I wonder how much it's actually losing at 14.7:1.
it likely doesn't run 14.7 at wot
@@richardholdener1727 I put a AFR gauge on it. Once the engine warms up it never really drops below 14.7:1, even at wide open throttle. It cruises down the highway at 17:1. Ive read this is how they were designed, but its the internet so who knows for sure.
The NA test is interesting to me because you say 36° is where it wanted to be but then you go on to say you prefer to tune in a safety margin, which I've also always done. Plotting your data points, your HP/degree drops from 9hp/deg down where it was obviously below the sweet spot, to 5.3 up to 31, and then 1.2hp/degree from 31 to 36. That tells me this motor would run well and last a long time with a healthy safety margin somewhere closer to 32 than 36°.
we run it where it stops making power
Duh Stock v-8 engine modified with street cam use stock 4 bbl carb and fine tune it , timing leave stock or a few degrees advanced. Play with it. Use differenet fuels. Yep it always worked .
More timing, less exhaust temp, less exhaust energy, less boost
Nice video.
Aside from melted/broken parts, what is the best indicator of finding optimum timing for a specific rpm?
You use a dyno. Keep increasing timing until you don’t see an increase in torque. There is no good way to “street tune” timing.
EGT exhaust gas temp and knock sensors
👆with boost you are often octane limited. Get some good fuel so when you go half a step too far it doesnt end your day and bump timing bit by bit. Some guys have done it with a G pro but its really hit or miss. An hour on a chassis dyno can sort out lots of a tune especially if you have it really close already.
full throttle runs with new plugs and ground strap inspection can work also if no dyno
Thanks for the timing experiment Richard 🙂
Was that 4.8 on 93 or e85? What timing would you suggest for 4.8, 78mm 93 oct, 6 psi?
WE USE E85 USUALLY WITH BOOST, 93 AND 6 PSI CAN RUN 18-20 DEGREES AT THE POWER PEAK
@@richardholdener1727 wow that much on 93? Sitting at 8 degrees peak torque and 11.5 degrees @ 5100-5700 rpms and it feels great, I couldn’t imagine 18 😳. Methanol injection will be installed soon, I’ll ramp it up then! Thanks for the reply, love your channel!
2:20 was that vtec I heard there?
double VTEC
Can you run this test on a gen 5 or 6 454?
same results
IDK, lower EGT's from advanced timing?
egts definitely drop with more timing
Definitely think boost pressure dropped because the motor became more efficient as you added timing.
What was the AFR on the Turbo setup?
11.6
I'd still love to see what a crappy late 70s or early 80s 350/305 did with poorly planned bolt ons with low compression crappy heads. We allll knew a guy with a pick up or Monte Carlo with a 750 Carb, intake, headers and "3/4 race cam" that claimed to have 450 hp.
Those setups make about 300 at best at the flywheel. Hell my 302 with the top end I want will make a little more than that
Why do none of these tests ever take into account Barametric pressure and the 30% plus power loss you'll get at higher altitude cities such as Utah or Denver.
why would I go test in Denver
What fuel was used on the turbo LS?
e85
What sort of timing do you think it would be if it was say around 95 octane ?
A 3-gear Ricky-Rev at 2:19!
My GTO Is set to 45 degrees locked 🤣
that should work well-but only under boost
@@richardholdener1727
It's the only way it would start. I got timing marks now I just gota put a light on it
just cant be off as much toward lean or too much timing.
If its a good set up 12:1 is still Rich as a thing that won't pass a petrol station.
Power seems to be in the mid 13's.
NO, JUST NO. THIS MOTOR MADE NO MORE POWER AT LEANER MIXTURES. THAT IS AN OLD WIVE'S TAIL! LEANER IS GOOD FOR CRUISE.
12 to 1 is a bit rich but isnt out of line from what OE programming is. It also only matters when it is wide open. If you are tuning for power, you give the jet the engine wants to make the power and deal with the fuel use especially if its only a quarter mile at a time. If your puttering around town as long as it stays close to stoic your really not wasting any fuel. There is very few gasoline engines that run stoic at full power. It takes a really tough engine with lots of heat abatement strategies to keep things alive. The ford 7.3l does this, it runs lambda 1 at all power levels.
There are certain instances where you WANT to run rich. The extra fuel can be used to cool the combustion temps.
@@richardholdener1727 You are testing motors with poor surface area discharge ratios. Only engines that are poor in efficiency need a rich mixture. Efficiency starts dropping disproportionately on bore sizes over 75mm. There also seems to be a big step change at over 86mm.
I've built a few engines over the years that are bigger bore shorter stroke but still to the same displacement and every time they need much more cam timing and fuel to make a small amount of extra power. The original Ford DFV was pretty much on the money if your using springs for valve control, 12000 ish rpm max. If your using air and can go another 2000rpm with your bottom end then all I've said goes out the window.
@@gothicpagan.666 dude...big claims. Jay from Woolich racing has been tuning motorcycles for longer than i have been alive and his arguments are antithetical to your statements. In a blog post regarding tuning the 2006 yzf r6, that has a 67mm bore, he said "...look for 12.8:1 in the acceleration region and 13.2:1 in the power region".
Now you have to make the argument that a 67mm bore is too big, or a sportbike engine that can run to almost 15k rpm has a poor surface are discharge ratio or you can admit that what youre saying isnt valid.
When you say that "only engines that are poor in efficiency are the ones that need rich a mixture" you have to give more evidence than a statement. Holdener shows dyno charts with lambda readings, i have given a source of a professional with a lifetime of engine development. You say one thing and dont show one dyno chart or give one source for a ford dfv with afr values attached.
1st view!!!
Ok too little degrees creates power loss but what about a motor that makes best power at say 34 degrees would that same motor lose power with say 40 degrees. I think this is a common mistake as most ametuers like to throw ALOT of timing jnto their motors
yes it will lose power then pistons
Add timing until it melts the electrodes off the plugs then back it off 1 degree
Does it run backwards ?? Hahaha
Wow, lost 150hp!!!
Atleast run 14psi of boost Rich
we did eventually, but not with different timing
Less egt
turbo is a little to small
Personally I blame squirrels