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5

A few things to consider if you end up doing this: A longer shaft will reduce the speed that you can safely spin the turbos up to It's got to do with something engineers call rotordynamics, although I highly doubt you would need to spin something up to 125,000 RPM for a turbojet application :) You may also find that the existing journal bearings are not ...


3

It certainly looks cracked. You could try spraying some EGR cleaner at the crack while the engine is idling. If the EGR cleaner gets sucked in through the cracked pipe, the revs of the engine will change, which will confirm you have an air leak.


2

This is a variable-length intake Variable-length intakes increase the pressure of the air entering the intake manifold thanks to a physical phenomenon called Helmholtz resonance. It's also known as dynamic supercharging since it avoids the use of a mechanical device (compressor/blower) to boost intake air pressure, which means the air enters the cylinders ...


0

There is an additional reason for not running lean, which applies very well to turbocharged engines - the extra fuel creates a 'boundary layer' between the combustion products and the cylinder wall. This absorbs extra heat during combustion to help keep the chamber temperature within tolerance. Modded cars that run very high turbo/supercharger boost are ...


6

Lean operation vs exhaust catalysts: The three-way catalytic converter fitted to gasoline vehicles can't operate under lean engine conditions because the reaction of NOx to nitrogen and oxygen is a reduction reaction, and for this to occur there needs to be a corresponding oxidation. In the three-way catalyst that is the oxidation of CO and hydrocarbons to ...


6

The 'floating' intake runners are moved by a mechanism, coupling and decoupling them from the main intake runners to increase the overall length for better low RPM performance. This process was recently discussed here: mech.SE on inlet runner length I don't see that having the extension pieces in the decoupled position would have any effect of the resonant ...


2

Running a lean mixture by itself isn't necessarily going to cause detonation, pinging or knocking. WW2 era old timer piston aircraft pilots used to run seriously lean mixtures on long hauls to increase range and it was safe to do so when they were at cruising altitude and power settings. You'd never consider doing it in a climb or at a high power though. ...


2

One additional point to touch on is that leaner and richer are relative to what conditions the engine already runs under. In terms of chemical reactions, car engines tend to run a little rich by default -- more fuel than is needed for all of the air -- because it reduces the frequency of detonations in the mixture. If you alter things so they run leaner ...


16

Lean ≠ More Air I believe the source of the misunderstanding is in how the term "lean" is being interpreted. A lean mixture doesn't indicate the presence of more air. It indicates the presence of a higher proportion of air compared to fuel (air-fuel ratio, or AFR). Quick example Mixture A has 1,000 g of air, 80 g of fuel. AFR = 1000/80 = 12.5 ...


8

It's not that the catalytic converter can't handle more air per se, it's that running lean increases the temperature of combustion (I actually don't know why, but now I'm curious) and the catalytic converter needs to run inside it's chemical operating range. Something to do with the chemistry that I also don't know. As for advantages for turbo boost and ...


3

I didn't see anyone mention it but I believe any increase in power would only be at wide-open throttle (WOT). So if you are racing or really aggressively pulling away from stop lights or accelerating, maybe it helps. Day-to-day driving at less than WOT the engine management system will keep the air-fuel ratio at an acceptable value. If it doesn't get enough ...


7

It depends. Just because an intake can flow more air mass doesn't guarantee that the engine will utilize it. The intake is part of a system of components. The engine produces power by managing air flow into and out of the combustion chamber. There are usually other actors involved: Intake side. Carburetors, throttle bodies, intake manifolds, intake ...


3

The working cycle of an 4 stroke internal combustion engine is like: (1) Inlet of the fresh air (2) Compression (3) Working Cycle - expansion (4) Exhaust Cooler intake air is especially beneficial for part (1). Since cooler air has a higher density, it means that the gas velocities at the inlet are lower. Therefore lower pressure losses at the cylinder. ...


4

Almost never? Mainly because they're really a 'hot air intake system'. This is especially true for cars using forced injection due to the high under-hood temperatures. If you want to reduce intake restriction look into a less restrictive 'panel' filter like a K&N. Even then, it really only matters if your car is intake (vs exhaust) limited and your ECU ...


14

Does this mod ever give a measurable increase in power? tl;dr: yes, sometimes it works well. But... Your picture is a good illustration of some of the problems with just saying "cold air intake" and expecting that to mean the same thing to all people. Let's break down the pieces of the puzzle and talk about how those might help or hurt: Filter: ...


0

Removing the acoustically engineered OEM intake and replacing it with a bit of pipe and cone filter is likely to result in a decrease in bhp. Most of the independent before and after tests done on non-turbo vehicles find that reduces performance.


7

The point is to feel like you've done something cool to your car and freed it from the shackles of The Man/the OEM intake. The primary benefit of Cold Air Intakes is to the bank account of the kit manufacturer, the secondary benefit is your car making a nicer noise, if you like the sound of an aftermarket intake. There's been a few debunkings of CAIs over ...


4

Would there be a substantial enough of a horsepower boost to be noticeable? The most you could see from such a modification is 15hp. This would not be enough for the seat dyno to register, unless there are plenty of hemorrhoids to detect it. More then likely you'd see a measly 5-10hp, and then only at the higher RPM levels would this be apparent. You ...


5

If the prints are just on the seal, I wouldn't worry about it. You could possibly take some gentle cleaner (Windex or Formula 409 or the like which will clean grease) and make it pretty again. It won't, however, decrease the function of the filter in any way. If they got a bunch of oil on the element itself, you might want to think about it. Really nothing ...



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