De-bunk the Myths! - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 01-25-2005, 01:30 AM   #11
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Quote:
Originally Posted by projectheavytouring
Quote:
Originally Posted by dblack1
ok here is some information about electric supercharger manufacturers... ill put the name of the product line first then the name of the company
e-ram by electricsupercharger.com
Thomas Knight Turbo Electric Supercharger by boosthead.com
jet stream by esuperchargers.com
instructions to build ur own electric supercharger by gaprojects.com
DragART Supercharger by DragART performance




and here is a thread from a ricer forum that has some info about people that actually did buy electric superchargers http://www.7thgencivic.com/forums/sh...3&page=1&pp=15
uhhhhhh the Boosthead.com electronic */c actually WORKS... it'* */c with 3 starter motors on it not a dinky electric fan... hense the high current draw and the time limit as per battery limitations... and hense the over 1grand price tag

as for getting rid of myths.... this isn't a manufacturer specific thing... but this whole "you need backpressure to run an N/A engine" thing has got to be stopped. backpressure is BAD for an engine... what alot of ppl think of needing backpressure is actually exhuast velocity ... while backpressure may remain in an exhaust tuned for exhaust velocity, the idea is to get rid of as much backpressure as possible, while getting maximum exhaust velocity. just think about it for a second or two ... back pressure... this is exhaust getting forced BACK into the combustion chambers... not a good thing
Cut your exaust off of your N/A'd car and let me know how it goes.

Something here called a "Juice Chip Module" I don't know what the hell it does, but looks worthelss and it'* $25 bux. Damn canucks!!! j/k Here'* an EBAY link, the only polace I've ever seen them:

http://cgi.ebay.com/ebaymotors/ws/eB...category=33597
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Old 01-27-2005, 07:15 PM   #12
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Quote:
Originally Posted by LakevilleSSEi

Cut your exaust off of your N/A'd car and let me know how it goes.
..... did you even READ what I wrote?... cutting off your exhaust would get rid of the exhaust velocity

you will never get rid of all the backpressure while running at optimum exhaust velocity .. the idea is to get RID of as much backpressure as possible while staying in the prime exhaust velocity... again you don't NEED BACKPRESSURE... it will just be there as a byproduct of gaining exhaust velocity.... the ONLY thing back pressure is GOOD for is engine braking down a hill
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Old 01-27-2005, 08:02 PM   #13
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Quote:
Originally Posted by projectheavytouring
..... did you even READ what I wrote?... cutting off your exhaust would get rid of the exhaust velocity

you will never get rid of all the backpressure while running at optimum exhaust velocity .. the idea is to get RID of as much backpressure as possible while staying in the prime exhaust velocity... again you don't NEED BACKPRESSURE... it will just be there as a byproduct of gaining exhaust velocity.... the ONLY thing back pressure is GOOD for is engine braking down a hill
hrmmm. now that just doesn't make any sense. you're saying that engine braking is because when your exhaust valve opens up, there'* exhaust putting sufficient pressure back on the piston to slow down a 3000 lb car. that would have to be a really restrictive exhaust system...

what i've been taught causes engine braking is really simple - since the engine is moving slower than the transmission, the transmission is forced to slow down - it doesn't slow the engine down - because of the engine'* compression, (not exhaust). the reason you don't feel this on an automatic transmission (unless you're in manual 1-2-3), is because the gears are designed to over-run if the engine speed is too low. when you're in manual 1-2-3, there are a few extra clutches and sprags that don't allow things to freewheel, creating a more solid link to the engine.
even so, in manual 1-2-3, you still will not have a complete link to the engine, because the torque convertor is a fluid coupling, and 'soaks up' differences in engine and transmission speed.

as for other myths to debunk, maybe we could start listing why they are myths - like the ebay chips that boast 25 HP - they are resistors that trick your intake air temp sensor (IAT) into thinking that the air is colder outside. as a result, the PCM provides a little extra timing. the problem with that, is the PCM figures out pretty quickly that a part of the equation is wrong - the air temp measurements don't match up with the emissions, pressure, etc. As a result, your fifty dollar ten cent resistor is over-ridden by the PCM that thinks the sensor is giving a bunk reading.
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Old 01-28-2005, 12:20 AM   #14
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Quote:
Originally Posted by mkaake
Quote:
Originally Posted by projectheavytouring
..... did you even READ what I wrote?... cutting off your exhaust would get rid of the exhaust velocity

you will never get rid of all the backpressure while running at optimum exhaust velocity .. the idea is to get RID of as much backpressure as possible while staying in the prime exhaust velocity... again you don't NEED BACKPRESSURE... it will just be there as a byproduct of gaining exhaust velocity.... the ONLY thing back pressure is GOOD for is engine braking down a hill
hrmmm. now that just doesn't make any sense. you're saying that engine braking is because when your exhaust valve opens up, there'* exhaust putting sufficient pressure back on the piston to slow down a 3000 lb car. that would have to be a really restrictive exhaust system...

what i've been taught causes engine braking is really simple - since the engine is moving slower than the transmission, the transmission is forced to slow down - it doesn't slow the engine down - because of the engine'* compression, (not exhaust). the reason you don't feel this on an automatic transmission (unless you're in manual 1-2-3), is because the gears are designed to over-run if the engine speed is too low. when you're in manual 1-2-3, there are a few extra clutches and sprags that don't allow things to freewheel, creating a more solid link to the engine.
On our cars thats mostly true, but have you ever hear a jake-brake on a truck? (The point at which a truck makes a REALLY loud noise going down hill)

So if youve ever ridden a gear (1-2 or 3) down a steep hill you can see that the engine actually slowly speeds up. The engines momentum is just so much greater than the force of the wheels pushing on it that it just stays slow for a while. Now if you were to almost completly cut-off the exhaust the engine would be held back so your car does , thats what a truck does. Now i wouldnt reccomend trying this to this extreme on a gasoline engine, but you get the idea? So your BOTH right At least as far as i can tell

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Old 01-28-2005, 12:35 AM   #15
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A jake-brake is just the engine not getting gas and not adding power to the cycle so it
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Old 01-28-2005, 12:40 AM   #16
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"When the driver presses a button in the cab to activate the device, two things happen. First, the switch excites the engine brakes' solenoids. By itself, this would help only a little but it is necessary for the second step. What happens inside of the engine goes roughly like this.

As a four-stroke internal combustion engine, each piston in a diesel normally moves up and down twice in each cycle. For the nit-pickers out there, there are many two-stroke diesel trucks on the road as well. The process begins when the fuel and air valves are closed and the piston moves upward. This compresses the air in the cylinder to as much as 25 times atmospheric pressure. This is much higher compression than a gasoline engine (typically ten times atmospheric pressure) and results in the air getting very hot, about 900 degrees Fahrenheit. At this time fuel is sprayed into the superheated air which immediately begins burning. The second stroke, the power stroke, is the downward movement of the piston as fuel burns. The third stroke is an upward movement with the exhaust valve open to clear out the combustion products while the fourth stroke refills the cylinder with air.

The Jake brake completely changes all this, redefining what the valves do as each piston moves up and down. With the fuel flow terminated, the upward moving first stroke still compresses the air to very high pressure. As we said above, this transfers mechanical energy into heat as the air becomes highly compressed. If nothing else were done, most of this energy would be recovered, except for frictional losses, as the cylinder moved back down and the compressed air expanded. The Jake brake, however, opens the exhaust valve just as the air reaches maximum compression, dumping all of that energy in an almost instantaneous explosive release. The result is a very effective slowing of the vehicle as mechanical energy is converted to heat and then dumped. The Jake brake effectively transforms the internal combustion engine into an air compressor. "

From: http://or.essortment.com/jakebraketruck_raio.htm

I was wrong, but it uses pressure... same kinda thing, just no fireing of the fuel... which could cause big problems so that makes sence.
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Old 01-28-2005, 12:43 AM   #17
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AHA.. but there is such thing as exhaust pressure brake:

" The Jacobs Exhaust BrakeŽ is a device that mounts in the exhaust system of the vehicle, and restricts exhaust flow when activated. It is virtually silent when in operation, and provides retarding power that is proportional to engine RPM. (Always stay within engine manufacturers recommendations). It is typically used on class 2 through 7 (medium duty) vehicles.

The Jacobs Exhaust Brake is a supplementary braking system used to help slow your vehicle. This slowing power is achieved by restricting the flow of exhaust gasses and increasing back pressure inside the engine. This increased back pressure creates resistance against the pistons in your engine, slowing the crankshaft'* rotation and ultimately helping to slow your vehicle."

From http://www.jakebrake.com/content.php4?doc_uid=25


EDIT: This should probably be split off into a forum titled "Everything you would ever want to know about Engine Brakeing and Jake Brakes... sorry ive been really off-topic lately.
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Old 01-28-2005, 01:13 AM   #18
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Yup. Let'* stick to the known and proven bullshit myths and bogus products for right now.
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Old 01-28-2005, 01:43 AM   #19
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ok i found another spiral twisty air thing...
its the tornado fuel saver from tornadofuelsaver.com

ok for some iat modules heres a list:

Hurricane resistor sensor modification from hurricane-horsepower.com
Velocity Performance Module from 20horsepower.com
Speedmodule and speedmodule pro from speedmodules.com

im sure theres more, but i just gotta find them...
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Old 01-28-2005, 01:47 AM   #20
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Posted 3 times in this topic already. It helps a tad with carbureted cars. But how many of those are still on the road?
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