Mythbusters.

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panic-mechanic
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Mythbusters.

Post by panic-mechanic »

Here are my favorite myths that I see repeated often most of them that has no basis in today's world or never had in the first place - in afrikaans they are known as 'ou vrou stories' stuff told from one generation to another by somebody that knew somebody that had an uncle that knew somebody that it happened to. Here are some of my most favorite hated ones in no particular order.

1) a cam vernier pulley allows you to shift the power band around to different points in the rev band. This one I'll bust straight off with a reference to this post. http://www.vwclub.co.za/phpbb3/viewtopi ... =3&t=95286

2) You 'need' to have exhaust back pressure otherwise it will burn valves.

3) You need an adjustable fuel pressure regulator to tune your car.

4) a lighter flywheel make your car lose torque

I'll add a couple as we go along. Let me add that none of the above are true and they are simply that - myths(I actually prefer bullsh!t) . If you REALLY want to I can try and explain why although I have actually at some point of the life of this forum done that. But these specific ones have surfaced again repeatedly recently and I can have a fit everytime I see it.
Feel free to add more and I'll comment where I can otherwise we can discuss and possibly test a few.
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Re: Mythbusters.

Post by RoadHaWg »

Not to sound soppy,

But I'm glad you're back :hi:
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Post by GtiTuned »

5) Compressed and cut springs work just as good as lowered springs. The ride is awesome. N force and razor springs are just as good as koni's, h & r etc.. Using th 60/40
drop makes ur car look straight and handle the best! (bull#$&t)

6) Fitting forged pistons allows me to boost to 1.5-2 bar, and it wont break thats why i fitted them. :bang:
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Re: Mythbusters.

Post by BlueBlob »

Here's 4 more:

7) Big intercoolers or long boost pipes give more lag. Crap.
8) the whole 8V makes more torque than 16V thing. Crap.
9) You can raise the octane of your fuel significantly by adding 7ml of some liquid. Crap.
10) Boost puts more strain on engines. Crap.


edit: Nice thread, by the way.
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Re: Mythbusters.

Post by maxxis »

Thought this was about the show on DSTV :D

Anyhoo some from me about audio

11) Fitting a noise suppressor to the RCA cables will remove alternator whine. Not quite true. While it may help its a stupid solution since you will lose sound quality. Diagnose and sort the problem out correctly. RCAs should never be close to power cables or ECU or similar electronic equipment. Also use proper cables.

Ill add some more when I have more time.
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Re: Mythbusters.

Post by panic-mechanic »

Thanks BB - yes no 8 is one of my favorite ones.
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Post by aran.com »

guys how can you leave out the vr6 myth

12) fitting vr6 injectors
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Re: Mythbusters.

Post by BlueBlob »

aran.com wrote:guys how can you leave out the vr6 myth

12) fitting vr6 injectors
Absolutely. Kinda ties in with the FPR that Panic mentioned. More fuel does not equal more power.
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Re: Mythbusters.

Post by BillyBob »

BlueBlob wrote:7) Big intercoolers or long boost pipes give more lag. Crap.
Larger coolers and more intricate boost pipe bends do however cause pressure drops.
BlueBlob wrote:10) Boost puts more strain on engines. Crap.
You're going to need to quantify that one... More boost = More torque = More pressure on bearings & con rods = Higher internal operating temps = Quicker oil breakdown... Furthermore, show me an N/A motor that can lift the head from the block? ;)



Oh, and chipping in my own little myths:

13) FSi eliminates the need for using the highest octane fuel available for the best performance

14) A 10-20% mixture of Toluene and Xylene added to your petrol will give you 120-octane

15) Water injection makes more horsepower on a dyno
Sometimes, we need to remind ourselves of the simplicities of life - you only need two tools: Duct tape and WD-40. If doesn't move and it should - use the WD-40. If it shouldn't move and does - use the duct tape.
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Re: Mythbusters.

Post by Jetta2 »

16) VW 8 valve motors cannot be turbo'd (yes, heard that so many times it makes me sick)
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Post by sjs »

Awesome thread Panic, not to sound soppy too but I'm glad you're back.
17) The use of a VR6 throttle body increases output (power and torque) and/or throttle response on an 8v motor.
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Post by Vinnige Fanie »

18)Cone filters make more power :crazy:
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Post by BillyBob »

Vinnige Fanie wrote:18)Cone filters make more power :crazy:
When well-isolated from engine bay heat, they do in some applications - especially on larger capacity & turbo engines.
Sometimes, we need to remind ourselves of the simplicities of life - you only need two tools: Duct tape and WD-40. If doesn't move and it should - use the WD-40. If it shouldn't move and does - use the duct tape.
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Post by GolfGTI »

19) Opel's are faster than VW's :crazy: :lol:

Sorry, could not resist, nice thread and it is good to have Panic back. Nice knowing we can learn from peoples own experiences. I know I have....
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Post by panic-mechanic »

Ok Billybob - let's have a quick look. - Boost doesn't mean higher operating temp. If you have that then it means either you have tuned the engine incorrectly as the ignition temp of different volumes of fuel at the same air/fuel ratio should be the same. What you have is more fuel being burned so you should have provided for more cooling capacity. A lack of cooling capacity means higher temp but that simply means the setup you are running is lacking - it's not because of boost as such....

In moderately boosted engines the actual pressure on the bearings should not be more as you should have complete combustion by the time the piston is almost all the way down the bore. Cases where the head gets blown off the block as you put it is normally related to catasthropic engine failure during EXTREMELY high boost operations running methanol and nitro methane ie. top fuel racers. if you have seen that in a normal car then it means somebody made a big boo boo with NOS most likely.

As for not turbo charging 8v's That is something that relates more to the VW U-flow head setup and although it can and has been done it remains a ball ache as you forever have space and related issues. I don't think anybody has meant that as an issue for 8v engines in general. The 8v x-flow made turbo charging a lot easier.


Oh yes - water injection actually does make more HP if done correctly and tuned for it.
You can work out the octane value you get from using xylene/toluene. Toluene has a base octane value of 114 and xylene 116
Here is a handy calculator you can use for any base octane calc.
http://www.elektro.com/audi/toluene/
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Re: Mythbusters.

Post by Jetta2 »

panic-mechanic wrote:As for not turbo charging 8v's That is something that relates more to the VW U-flow head setup and although it can and has been done it remains a ball ache as you forever have space and related issues. I don't think anybody has meant that as an issue for 8v engines in general. The 8v x-flow made turbo charging a lot easier.
When I started my U-flow turbo build I got a few PM's telling me it is impossible to turbo ANY 8V VW motor. I told the 3 people who sent the PM's to watch and learn.
Yes, there are space and heat issues, I know first hand, but it certainly is possible, and the X-flow set-ups make it a hell of a lot easier and simpler.
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Post by SHAUN »

20) 16valves are for people that dont know how to make power with a 8v
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Re: Mythbusters.

Post by BlueBlob »

SHAUN wrote:20) 16valves are for people that dont know how to make power with a 8v
There is at least a little truth to this though; much easier to make big HP with a 16V.

But the statement in itself is stupid.
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Re: Mythbusters.

Post by sixteen10 »

SHAUN wrote:20) 16valves are for people that dont know how to make power with a 8v
thats not myth , thats FAX!!!!


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Post by sjs »

Please make this a sticky and/or topic in FAQ section.
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Re: Mythbusters.

Post by panic-mechanic »

As far as how many valves - let me say this and this is simply the basis of how ANY engine
develops power. I have done this a few times but people seems to constantly forget the
simple basic truth.
An engine is simply an air pump. There is only one way to develop power and that is to burn
fuel. Burning x amount of fuel releases Y amount of power. That is a basic fixed scientific
ratio and stays the same for each type of fuel(ie petrol/diesel/methanol or whatever you
choose). RIGHT so now with that in mind - immediately the first thing that you know is that
you need to burn more fuel to make more power. GREAT this is exactly where the problem comes in - max power only happens at a specific Fuel to air Ratio(roughly at 13.2 to 1) so in your correctly tuned engine giving optimum power you cannot simply add more fuel - no What you have to do is add more AIR - THAT in turn means you can now add more fuel....RIGHT - so howdo you get more air in?
1) Bigger capacity
2) Better effieciency - in other words getting more air into the same capacity engine by
making it breathe better.
3) forcing more air in under pressure( turbo or supercharging)

So Let's discuss point 2 - this is where most of the work happens in N/A engines. To do that
you basically have to get an engine to breathe better.So how does an engine like this get
air in - yes it simply draws the air in (or shall I say the air flows into the void left by
the dropping piston) Either way - the Less restriction there is in the way of this happening
the better the cylinder will be filled. The higher the volume of air yu can fit into the
Hole left by the piston when it gets to full capacity(basically BDC) the More fuel you can
burn. So basically - valve open - pistons storms down - air follows in valve closes and air
gets compressed with the piston on the way up. Because air has mass you can get away with
closing the valve after BDC(this is the basis that longer duration cams work on). So now
basically the bigger the hole you can provide for the air to rush in when the piston goes
down the better the cylinder gets filled. If you think about it logically it is impossible
to get the biggest size hole by using 2 valves only. The more smaller valves you use the
better you can arrange them to make a bigger opening. Hence 4 or 5 small valves per cylinder
is better than 2. It's simple mechanical/scientific fact.
Phew sorry all that to say a 16v is better than an 8 valve.
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Re: Mythbusters.

Post by PoLonY »

nice topic
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Re: Mythbusters.

Post by bru-tom »

panic-mechanic wrote:
4) a lighter flywheel make your car lose torque
Awesome thread Stephan!

Regarding the quote- lightning a flywheel allows your engine to rev up quicker,however you loose momentum right?

I read somewhere that it can be dangerous when shifting down and the motor drops revs too fast and can cause damage? Any info on this?
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Re: Mythbusters.

Post by panic-mechanic »

A lighter flywheel cannot cause any damage. Yes it allows the engine to spin up faster and yes it slows down faster. It actually allows sligthly faster gearshifts. An engine that hangs onto RPM doesn't allow fast gearshifts in general.
What you lose is the kinetic energy transfer as you pull off - so you tend to have to use a little more throttle to move off - specially on an incline. What a heavy flywheel achieves is basically exactly like the little flywheel toy cars work - you wind up the flywheel and it rushes off till the energy in the flywheel is depleted. A car's does the same - it stores potential energy and turns it into kinetic. Without a flywheel or a very light flywheel the engine does all the work - not the 'storage device'. If you have ever looked at a formula 1 engine you'll know they don't have a flywheel. Under load at a constant RPM at the same throttle opening an engine with or without flywheel will make exactly the same torque and power. The same with Bike engins - very little flywheel there.
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Re: Mythbusters.

Post by bru-tom »

Thanks Stephan... So me running an abf with smaller ffz flywheel,its essencially already lighter than stock?
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