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Ram Air Causing Fouled Spark Plugs And Fast Idle

dougelam

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Huh?

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Hib Halverson

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71 04 12 19
My hood is an L-88 "style" hood that has the L-88 type of additional 2" dome and that's all. Just LOOKS like an L-88 hood from the outside. Knowing my taller Air Gap intake would require a taller hood I bought this one but ran into trouble when I tried to run the common 14" X 3" open dropped-base air filter. I managed to reduce the height of the dropped-base by about 5/8" and had to remove 1/4" from the Air Gap's surface and finally ended up with about 1/16" hood clearance. Using my water manometer I found there is a vacuum at the base of the windshield when running an L-88 hood because the additional 2" dome pushes the air upward like an airplane wing. The manometer revealed there was no pressure until about 1/2 way up the windshield so I decided to use a frontal intake for my Ram Air. The original L-88 hoods may have had "cold air" but not "ram" air because of their additional 2" dome.

So :eek you are disputing decades of testing in your conclusion that, when a C3, with an L88 style hood, is moving at high speed, the space at the base of the windshield is a negative pressure area. Is that correct?

Do you know that in the late 60s GM spent a ton of money developing that hood profile in a wind tunnel. The point was to give the road racers a way to get a hood over the high-rise intake manifold and Holley 4-bbl L88s used and a way to have cold air forced into the the volume of space under the hood and around the air cleaner assembly. Are you saying GM's research and development engineering was faulty?

What pissing contest? I have never said a single derogatory word against any of you even though many of you have been bashing me all along.
To me a "pissing contest" is a pointless argument:argue. Posting a "derogatory word" or "bashing" would be a "flamewar":flaming in my lexicon.

I have simply stated what I was doing and why I was doing it in my troubleshooting process to find out why I suddenly had a dead #2 cylinder. (snip)
I'm confused.:confused I thought we were talking about Holley choke assemblies. How'd we get onto plug wires? But, ok...you say that you spliced a plug wire?!
I've been on the CAC since it began and read a lot of strange posts, but I've never heard of anyone doing that. :werd: but, WTF...if it works and you can't afford a replacement wire. But for sure...like you said...don't let that sucker get near a ground.

There is no direct correlation between high gears and fuel mileage.

Just so I understand...you are saying that for a given speed, going to a taller axle ratio is not going to gain fuel mileage? That seems to go against the conventional wisdom. Would you be willing to post a few facts to lend some credibility to that statment?

An Air Gap combined with a long duration cam and high gears is a disaster because runner velocity is so slow fuel drops out of suspension. When I was running the stock 3.08's my fuel mileage was a dismal 8 mpg but it shot up to 10-1/2 mpg with the lower 3.70's because the runner velocity increased. That is why the CrossFires and Tuned Ports had small diameter LONG runners to keep runner velocity high to go with the tall 2.87 gears. My Magnum cam is rated for 2200 to 6200 rpm and so I geared it to achieve 2250 rpm at 65 mph. With a near-perfect match between the torque band and the final gearing my 454" gets pretty good fuel mileage at cruising speeds. It started off at 8 mpg and it's now getting 14 mpg..................a 75% increase with about 75 more horsepower; proof that I am doing something right. And with my engine now hitting on all 8 cylinders it'll probably get 16 mpg at freeway speeds.

I have a Performer RPM (no air gap) on the 460 in my 71. I did not have to machine the top of the intake to get it to fit. I have an actually L88 air cleaner base to which my fab guy used for the basis for an airbox that surrounds my carb and is open at the rear. I run a 4-inch Green Filter. I have an Ecklers 73-79 style hood which is higher than stock to clear my induction. My cam has about the same lift and intake duration but more exhaust duration than your Comp hydaulic, but it's a mechanical roller so I'm getting the valves open quicker so I have more area under the curve. I have ported oval port heads with L88 valves. Carb is an 850 Holley with an automatic choke. It began life as a Fuel Curve Engineering road race carb and I modified it with a choke and extensive recalibration of idle and part-throttle. The axle ratio is 3.08. The trans is a six speed with high-gear being an overdrive. I shift at 6500. The rev limiter is at 6800. Power is 540-550–not much to talk about by today's standards, but it was pretty awesome in 1992 when the engine was built.

The last time I ran a fuel economy test was back about 2010, right after I did some more work on my 850. The test was 250 miles, a 70/30 mix of highway and city driving and never over the posted speed limit. I got an average 16.9-mpg.

Try tuning your Holley for part throttle. Get that right and you'll get that 16-mpg you want.

Oh, and, hey...I still want to know how you got those V-16 locomotive engines into your shop.
 
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kpic

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Mar 29, 2014
Messages
2,292
Location
Columbus, NC/NE Georgia
Corvette
1997 boosted silver coupe

Someone doesn't understand high voltage and a whole bunch of other stuff. Even worse, he loves flaunting it.

Hib:

Well said and it appears as usual someone knows better. Even worse, he doesn't remember what he says. Same as the ever ready bunny, he keeps going and going.

Toobroke...:
You called me stupid. Which is not a way to win friends and influence people. As former engineering management; I would have had the pleasure of furnishing you with a few cardboard boxes.
Point is, to everyone you're a crock.

If you want an increase in MPG, inflate your tires to the recommended pressure found on the sticker on the door or the B pillar.


 

Antz81

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Dec 21, 2013
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936
Location
Auckland, New Zealand
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1981 4 speed
There is nothing wrong with splicing a spark plug wire as long as that splice isn't close to a ground. In my case my large-diameter Ram Air filter base was hanging over the top of the front two HEI terminals and I wasn't aware of how close those terminals were to the base. The terminals now have a full inch of clearance (actually about 1-1/8") so there shouldn't be any more problems with flashing to ground. I had created the problem and once my #2 cylinder suddenly began misfiring on my coast trip I was determined to find the cause.

Due to the high voltages I don't believe splicing a spark plug wire is safe at all. Regardless of how far it is from a ground.

I don't believe the distance to the air cleaner was in issue, it looks similar to what I have on my (stock) 81.
 
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Apparently your #2 cylinder disagrees with your theory. :chuckle


Take a good look at the high-voltage power lines that stretch across the country. None of them have insulation and they are all spliced with u-clamps every several hundred feet. Or haven't you ever noticed that?
 

dougelam

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2002 Roadster
Are you serious? (Sorry Mac)
And you are an engineer?

My 6 year old grand son knows the difference between AC & DC voltage

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dougelam

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2002 Roadster
I can only imagine what would happen if someone attemped to power up a house using a capacitor discharge system

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dougelam

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It would be similar to a Tesla coil

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kpic

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Columbus, NC/NE Georgia
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1997 boosted silver coupe
Take a good look at the high-voltage power lines that stretch across the country. None of them have insulation and they are all spliced with u-clamps every several hundred feet. Or haven't you ever noticed that?

As my electric fence demonstrates, air is an excellent insulator.

About 90% of all high voltage overhead lines are covered will a weather protecting coating. As they do not make contact with the ground in any way shape of form; the insulators at the towers do the job. However, they are well out of reach of humans. Handling high voltages close to the ground is an entirely different subject.

Here is 3M's thoughts on the subject:
http://multimedia.3m.com/mws/media/41103O/high-voltage-power-cable-splicing-terminating-brief.PDF

See page 7 for splicing.

Here are some pictures of some high voltage splicing devices:
Splice


These are as close as I can find to u-clamps:
https://www.aflglobal.com/Products/...are/SkyWrap-Termination-Joint—Phase-Wire.aspx


In an earlier post, you mentioned you are open to learning. Well, here is an opportunity.

BTW, by saying insulation isn't used with overhead high voltage; are you saying you didn't insulate the plug wire?
:chuckle
 

Hib Halverson

Technical Writer for Internet & Print Media
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71 04 12 19
Take a good look at the high-voltage power lines that stretch across the country. None of them have insulation and they are all spliced with u-clamps every several hundred feet. Or haven't you ever noticed that?

Wait-what?!

Now you're trying to convince us that the high-voltage, high-current AC power grid is similar to the high-voltage, low current DC power which runs through the secondary ingition system on our Vettes? Further, that we can "splice" plug wires with u-clamps?

This thread is getting a bit odd, I have to admit.
 
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dougelam

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2002 Roadster
Take a good look at the high-voltage power lines that stretch across the country. None of them have insulation and they are all spliced with u-clamps every several hundred feet. Or haven't you ever noticed that?
Is there such a thing as a shade tree engineer?

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kpic

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1997 boosted silver coupe
Wait-what?!

Now you're trying to convince us that the high-voltage, high-current AC power grid is similar to the high-voltage, low current DC power which runs through the secondary ingition system on our Vettes? Further, that we can "splice" plug wires with u-clamps?

This thread is getting a bit odd, I have to admit.

Plus there aren't any U-clamps on HV power lines. However, I must admit I never knew that until I looked it up.

Very odd.. Personally, I haven't gotten past under inflated tires yet. ;)

To be quite blunt, the only reason I mess with this "stuff" is I don't want lurkers or prospective members of this site to believe this "stuff" is a representative of CAC.


Is there such a thing as a shade tree engineer?

Nope, there sure isn't. OK, maybe an agricultural engineer. ;)

However, there are engineers who work on their own vehicles. They apply profanity when applicable at factory stupidity same as you do.
The real world is quite different than the office. Getting one's hands dirty reminds us office idiots that someone has to work on the $#%^ thing.
I enjoy getting my hands dirty working on my own vehicles.

 

Antz81

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Messages
936
Location
Auckland, New Zealand
Corvette
1981 4 speed
Take a good look at the high-voltage power lines that stretch across the country. None of them have insulation and they are all spliced with u-clamps every several hundred feet. Or haven't you ever noticed that?

As the others have said those powerlines are totally different. AC can behave very different to DC. Plus they are sperated by several feet.
They are certainly not spliced with u-clamps either. I would imagine that they are spliced with c-crimps, which are much more secure, and conductive.

Kpic said on another thread he's not sure what i do for work. Guess what, I'm an industrial electrician. I had to learn about the power distribution system and requirements as part of my training.
 

Hib Halverson

Technical Writer for Internet & Print Media
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CenCoast CA
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71 04 12 19
Heck...I didn't think they even had electricity in New Zealand. :chuckle

:w
 

kpic

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Mar 29, 2014
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Columbus, NC/NE Georgia
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1997 boosted silver coupe
As the others have said those powerlines are totally different. AC can behave very different to DC. Plus they are sperated by several feet.
They are certainly not spliced with u-clamps either. I would imagine that they are spliced with c-crimps, which are much more secure, and conductive.

Kpic said on another thread he's not sure what i do for work. Guess what, I'm an industrial electrician. I had to learn about the power distribution system and requirements as part of my training.

Not to to pick on toobroke... However, I am beginning to understand why he is too broke to retire after he rubbed my nose in it so often.

I believe toobroke was talking about guy wires; not power transmission lines.

My excuse for a brain is imagining his spliced plug wire. ;LOL


Heck...I didn't think they even had electricity in New Zealand.
:w

That was unexpected and quite funny, Hib. As there may be incoming from New Zealand be prepared to duck. :D:D
 
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It Happens To The Best Of Us

Make fun of me and bash me if you wish but the whole point of this thread was to walk you the troubleshooting process I used to find the reason why my #2 cylinder wasn't firing on my coast trip. It was caused by ME as I didn't realize my spliced #2 wire was so close to the rear of my air cleaner base that overhung the front two HEI terminals. In the end I found the reason and modified my base to allow about 1-1/4" of clearance. With my #2 cylinder now firing all the time I had to reduce my idle speed a tad.
 

dougelam

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Messages
453
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Michigan
Corvette
2002 Roadster
The ridicule stems from your backyard approach to diagnostics and when we comment with valid and positive opinions you totally ignore it and repeat the same ideology without any acknowledgment of what was just suggested!

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