Steve that’s great info, I just spoke with you other day on my build you guys went thru for me recently as needed suggestion on pulley sizing to slow blower and decrease some boost but I think my tuner was having same issues as at 20 lbs on pump having to pull so much timing ignition wasn’t happy at all, I knew as soon as he told me had to close plugs waaaaay up and it has rough spots where flame 🔥 front is clearly not happy, knowing what actually happens in a engine like you just explained saves you from trying to tune around a problem and actually fix the problem, thanks again for all you do sir.
Timing over boost normally always will make more or better power. As long as the fuel can keep detonation under control. Just had this conversation this morning with an old timer engine builder in my area. What a coincidence. Nice video!
I agree with you 100. I watched Rich and Nich Bruder take a f3-136 540 bbc making just a touch over 2800 rwhp add 1 degree of timing and Jack out 3450 rwhp on the hub dyno.
I’m reading about this in an engine building book and supercharger design. It all comes back to air density and temperature. The faster the blower turns, the more temperature is generated in the blower and transfers to the air. There is a point at which this becomes negative for air density in the combustion chamber preventing good burn of the fuel. With that said, density altitude changes will have an effect on the tune. There is a lot of science behind engines, especially OEM engines now just to pass emissions. When it comes to blowers, bigger is better. Always great info here, keep it up
Loved the video Mr Morris! I remember when I boosted my 2016 2ss camaro new. with a 2300 blower and went to a 2650 with a ton more cooling 4 years ago. The 2650 spins slower(8”lower) the upper pulley is now a 4” compared to to the 2300 with a 3.75” I am running less boost but a much lower iat and I have more timing and more power to the rollers.
no, actually, this is literally entry level concept. Blower manufacturer will tell you exactly this. Compressor Efficiency has been a thing since about WW2
@@realtuners707 Yeah. Thats why the Rolls Royce Merlin engine and the US/Canadian Packard version had 2 speed blowers that were for different altitudes. Although I'd say they knew a great deal about it even earlier than that, in the 30s for example Bugatti and other brands were figuring a lot out about blowers on their racecars. Mercedes comes to mind as well, there were others though, back in those days the straight 8 was the winner
Love your videos! So many people are always throwing more boost at an engine on weak fuel and pulling timing out when they could back off the boost and go it better with better timing. I wonder if the engine would've responded to even less boost with more timing?
First off, I love your channel, you do phenomenal work. This brings up a question for my application. I have a 2000 supercharged m45 mazda miata with a nose pulley reduction from 67mm to 62.5mm during the dyno pulls I could see a dip then hump before it starts to plane itself out. Mine occurs around 2600-3200rpm but then comes back in fine. Would tuning my ignition timing in this area help with the dip to regain the loss of power? If so which direction is best? I've heard that the Eaton m45 (roots/hotside) supercharger has this typical characteristic and have gone with that but it has never made sense to me as to why.
Love the setup, care to share the info on what kind of 90 deg. Elbow that is? Looks low profile compared to most which would greatly help out in my 4th gen Camaro
I know this is a supercharger, not a turbo, but: You know one thing you've never thought about before? If you are running a turbocharger and have to dial back the timing to use lower-octane gas, it puts more energy into the exhaust gas due to later timing, which energizes the turbo better due to later combustion. That energy that WOULD have been used to push down that piston is instead having some of it go into the exhaust flow because the spark happens later. So, the irony is that with a turbo motor, you may get more responsiveness from the turbo if you time it for 87 octane gasoline, due to a more-energized exhaust stream. You will get more overall power from hi-test gas, but you will get a quicker turbo spin-up from the low-buck gasoline. Try it on a turbo motor some time and watch the boost response curve of the same gas timed for 110 octane and then timed for 87 octane. More power used to push down the piston with the advanced timing, more energy spinning up the turbo on the 87 octane-suitable less-advanced timing. I guarantee you you have never thought of that before. Tuning for cheaper gas on a turbo motor can flatten your torque curve. Lower overall power, yes. SOONER turbo response, though, also YES.
So how much slowing down did it take to get the boost cut that much, 20%? Makes perfect sense to me that at a certain rpm it takes a specific advance for the fuel to be igniting as close to tdc or just after as possible. at 13 deg and 4000+rpm that ignition event(peak cylinder pressure) would have been way after TDC killing power and making lots of heat.
It has never crossed my mind that the lower the timing advance the higher the cylinder pressure when the spark plug fires. But it seams so obvious now.
i know that top fuel engines have 2 and 3 spark plugs a cylinder and the giant mags to fire them off and there are european engines not highend ones either that run twin spark , has this ever been used on a 'regular' engine to check if it is viable or is it too complicated
The higher the pre ignition pressures are, the faster it burns. Shit, 13 degrees at speed, the cylinder pressures don't last enough time to ignite the fuel under pressure. By the time it's really lit, the motor is well past tdc.
A spark isn't a flame. It doesn't blow out. Slowing down the blower is akin to reducing turbo impeller speed, your CAC does less work and your MCT is lower, of course you're able to advance that spark closer to the engines CA50 before you become knock limited.
@@jasonritter2492 Try putting nitro in a BBC style engine or high boost against a HEMI, ya it's been done over the decades, how did that work out? I almost forgot nhra had to give weight breaks for the GM style head to be competitive. And don't forget when factory engines raced nascar and HEMI dominated. I could go on but you can read the history. Ya and guy's by proline HEMI not to go fast but to get chump change for their program LOL.. fyi, your torque down low BBC engine does NOT win against a high rpm higher hp hemi unless handicapped. Nice try..
Ya, when you cannot defend your block of aluminum cylinder head that cannot bolt up to a real BBC block, like a 1964 hemi can to a top fuel block, ya you know like bore spacing, all you can discuss is Falling nhra, and crowd counts. Bring your BBC to a real drag race, you know 300 plus mph stuff but you wouldn't get off the starting line. Who's in lives in fantasy land, and if you want more torque than your BBC build a pontiac, has 300 less hp, my friends say it's more reliable LOL..nice try
