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That brings me to the second part of my comment/question. As fuel injection and especially direct injection are unlikely to produce stand off or an unintentionally rich mixture what do yo do to create the lumpy idle effect. How does it affect emissions?
 

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Discussion Starter · #62 ·
Lumpy idle, ie "ghost cam" as referred to by many, is mostly adjusting the tune so that the valve timing has more overlap. It will change emissions in that area of the tune but not sure what will change or by how much. It will pass inspection though.
 

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"Lumpy idle" is officially my new favorite term.

Also, @trdtoy, thank you for this entire thread, this is an unspeakably valuable resource.
 
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Discussion Starter · #64 ·
"Lumpy idle" is officially my new favorite term.

Also, @trdtoy, thank you for this entire thread, this is an unspeakably valuable resource.
Welcome! I'm here to help. I need to add more to this thread and add new threads but I have been busy lately.
 
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Lumpy idle, ie "ghost cam" as referred to by many, is mostly adjusting the tune so that the valve timing has more overlap. It will change emissions in that area of the tune but not sure what will change or by how much. It will pass inspection though.
I've seen Camaro guys and Mustang guys tune for this lumpy idle for that cammed sound. 🙄
Sure it sounds great but when it's time to show the ponies all you see are Shetland's. 😂😜
True story.
 

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Discussion Starter · #66 ·
Well I mean its not set cam timing so you can get the sound and power gains as well.
 

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Sufficient knock suppression

The ecu will adjust ignition timing +/- and thus power output +/- by itself based on the amount of knock the engine has at any given time. Higher ignition timing equals more power, lower ignition timing equals less power.

High octane fuel

Higher octane fuel resists knock thus allows the engine to run higher ignition timing without knock than lower octane fuel will allow. This is one reason why 93 octane fuel will make more power than 87 octane fuel.

Proper air fuel ratio

The VT ecu operates on lambda instead of air fuel ratio. 1 lambda is 14.7 air fuel ratio on pure gas with 0 ethanol added. Most pump gas now has 10% ethanol which lowers the air fuel ratio at 1 lambda to 14.1. For simplicity let's stick to the pure gas scale.

The range of the air fuel ratio to not cause knock or suppress knock will be in a small range. This air fuel ratio range will usually be from the 10's to 12's. Below somewhere in the 10's will actually cause something called rich knock. Being too rich(below 10's) in general will kill power and knock kills it further. Being too lean(12's and higher) in general will kill power and at some point will cause knock that will kill power further.

Example:

Lets say a tuned VT makes 250 whp with 11.5 air fuel ratio and does not pull any timing. Car is leaned out to 12, makes 255 whp, and does not pull timing. Lean it out to 12.5, makes 250 whp, but pulls timing. Now it's not safe as the ecu is now pulling timing from insufficient air fuel ratio. The safe afr would be the point just below where the ecu will pull timing due to knock in a given scenario/conditions.

Now the same VT is richened up to 11 air fuel ratio, makes 245 whp, and does not pull any timing. Richen up to 10.5 air fuel ratio, makes 240 whp, but now pulls timing. Not only is more fuel to make less power inefficient, but richening to the point to cause knock is dangerous just like being too lean.

The oem tune has the air fuel ratio in an efficient area to make power safely in a very small area. Most areas and conditions it will have fueling too lean and at other times too rich. Some aftermarket tunes widen this area of making safe efficient power and some do not do as well.

Water/meth injection

This adds air density and mass air flow at a given air flow from intake air cooling, which can be referred to earlier, and knock suppression through in cylinder cooling from the water, or the same plus added octane from methanol. Methanol cools better than water and has more benefits of the added octane which is why higher methanol content will make more power. Water on the other hand will cool things better inside and after the cylinder. Meaning it will also help lower the temperature of the turbo and exhaust gasses so things live longer.

Colder/more efficient engine coolant

The colder and more efficient the coolant the more timing and power the car will make due to less knock. Stock engine coolant tends to run in the 180°F area. Better thermostat and coolant will lower those by roughly 20°F. Doing this along with a more efficient coolant will allow in the area of 1°-1.5° more timing and usually nets 3-5 whp more.

Colder heat range plugs

The VT first came out with a heat range 6 plug which is a hot plug. In the 14 MY they went to a colder heat range 7 plug to help resolve misfires/knock. In the 16 MY they went to a colder heat range 8 plug to further resolve issues with misfires/knock.

The colder the plug the more efficient the plug is at staying cool. The cooler the plug the less chance of the plug being a hot spot in the cylinder to cause misfires/knock and thus power loss. The con is if you run the plug too cold it can get build up and also cause a loss of performance over time. So best to match the plug to what will work best for the car.
I am Loving the info you're putting on here!!! Do you know of any reputable references in regards to A/F or Lambda values? Is there a good way to record/map out lambda in real time driving applications so someone may be able to adjust accordingly??

Thanks!!!
 

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Discussion Starter · #68 ·
Yes, lambda needs to be in a certain range for best power and safety. Can easily be viewed and datalogged real time but can't be adjusted real time. That requires tuning.
 

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Kinda of abstract question on the topic, I've been getting into BMEP and VE a bit more in regards to limits of stock internals.

If you increase VE through quality high flow parts, the car would make more power with less stress correct? Can you overcome certain structural limits of an engine with better parts? For example, increasing VE on a stock turbo setup sees less losses, leading to higher than average power out of the stock turbo in comparison to less efficient setups. Or main studs being an issue at ~380, would an increase in VE lessen the load it takes to make an amount of power, allowing you to surpass the physical limits?
 

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Discussion Starter · #70 ·
Each part has a breaking range rather than a set point. That range will vary based on the stress the part will see, how suddenly that stress is applied, the duration of the stress, heat plays a role, and in some cases lubrication, and many other factors. All depends on the part in question.

Higher VE means more efficient power that makes it easier on some parts and harder on others. This is the best way I can answer these questions without getting too detailed.

Regarding 380 whp on oem internals only 2 cars I know of has done that. One lasted less than a week or two. The other was fine but never ran that power level much at all.
 

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That makes sense, stress has to go somewhere I suppose. I'd like to see a version of your original write up for the 300-400ish range, as you mostly focused on the stock to the FBO range. Because marketing would lead the masses to believe you just need to slap head studs and a turbo on and you're good to go, If that's the case, great. But there isn't enough information out there. It's exciting to see the G4FJ creeping up in safe power as knowledge is passed around.
 

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Discussion Starter · #72 ·
The information is out there for the most part just let me know what you want to know. Marketing can be misleading for sure because in most cases will be partial truth solely to sell something. Cons and other things needed to accomplish a goal are rarely stated.

Also "safe power" is a very relative term. Really it should be looked at safe for x time under x conditions. What I'm saying is that a setup may make 400 whp safe for say 10 seconds but same setup make 300 whp safe for 10 minutes. So just stating safe power is meaningless without another measuring tool placed with that statement.
 

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That's fair. redline for 5 minutes would probably do a number on many engines.

Ignoring the trans pipe dream lol... I have all the parts I need to potentially make at ~350whp, maybe more on e85/methanol (400 is the goal. But I have no plans to spend money on performance parts. and I'm not interested in the cost of building out the block to go further than that.). But I'm not sure what I need to be worried about with internals between 300-400 that.

Is a tune capable of 380whp reliable enough to daily? Does babying the car become more a concern for the driver? Is the car less likely to fail if you're rarely reaching max effort due to changed driving habits? And if that's the case then is it better to have a tune you can go flat out in that's "safer"? Things like that are my concern for this power range.
 

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Is a tune capable of 380whp reliable enough to daily? Does babying the car become more a concern for the driver? Is the car less likely to fail if you're rarely reaching max effort due to changed driving habits? And if that's the case then is it better to have a tune you can go flat out in that's "safer"? Things like that are my concern for this power range.
Yes a tune is capable enough to drive the car the way you want it. That's the tuners job to know what they're doing and make it a beast on the streets on Mexico or go to get your groceries.
I follow several people running high hp cars on stock internals that are very drivable and send people to gapplebee's when needed.

Why baby the car. Proper tune and your good.

All your questions come down to the tuner and how he sets things up for the car.
@trdtoy would be one of those tuners I would trust with my car.

Side note though so don't take this wrong.
If you're really wanting this kind of power building the engine would be the best bet period.
Con rods, pistons, rings, arp studs everywhere, head gasket, and bearings are what you'll need for that near bullet prof engine that will last you for years.
Just saying. Save up for it if needed. 🤷🏼‍♂️😉
 

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Lol trust me, I'd be working with him if he was actively working on my unique situation.

Yeah I have head studs and gasket. I'm just unsure of the piston, rods, and bearings part.
 

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Lol trust me, I'd be working with him if he was actively working on my unique situation.

Yeah I have head studs and gasket. I'm just unsure of the piston, rods, and bearings part.
What takes the most brunt of the load with an engine with that much power it wasn't designed for are the con bearings, rings, and pistons. Higher boost levels will take its toll on those components.

You're half way there. 😂😁

I plan on 300-350 whp for my setup but I'm building the motor to handle 400+ if I want to go more and I'll ha e the satisfaction I can drive the car the way I want without any fear of the engine popping. 😳
I'll have a spare anyway if it does. 😂😁😉
 

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Discussion Starter · #77 ·
The more power the setup makes the higher the priority to upgrade parts, baby the car as a daily driver, and have the tune more fine tuned to make the setup more reliable. The better the setup the less need to baby anything.
 

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There’s some great info here but also a lot of generalizations and oversimplification. Perhaps a bit of conjecture too.
For example, discussing boost as psi is going to be very different for someone with an aftermarket intercooler vs OEM.
Yes, higher octane fuel resists preignition but it also burns much hotter. If you just start putting 93 octane in an otherwise stock car you might end up having some trouble with heat. If you have any deposits, you can get pinging. If you aren’t getting complete enough burn, you will get some/more deposits.
Piggyback tuners aren’t just trickery for fools. Admittedly some are though, but the days of piggyback tuners doing things like just lying about IAT or something like that are pretty long gone.
 

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I think the oversimplifications are to make sure it's digestible lol
 

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In any slice of the history of the internal combustion engine there is a max BMEP. That number continues to rise with the evolution of combustion chamber design and fuel delivery. Our engines are only about 100 cubic inches, that means in stock form 2hp per cubic inch. This is a rather respectable level of output. Can we increase that number? Of course we can, but as output goes up the tolerance for mishandling goes down. I remember seeing an old WW2 Jeep, stencil said the engine required octane in the sixties, I suspect it would have rune on kerosene, but output per CI was dismal. There is a price to pay for everything, increase power and you had better have a very tight control on temps, spark and afr.
 
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