chazman

iTrader: (4)

For all those who feel Splitfire sparkplugs suck.....would you feel that way if they cost 99 cents a piece?

Vader

Yes,

I can get them for $1.99 at any of our local Farm & Fleet stores, and have been able to for a long time. It isn't the price that is flawed, it's the theory. Despite what they want you to believe, multiple spark paths are not a good thing for performance. I'd rather pay $9.00 each for a true platinum plug with single electrodes, thank you.

And before someone pipes up about aircraft engines having mulitple spark PLUGS, they had better go out to the tie down and look closely at the whole package - get all the data, we'll wait.

99% of powerplants in civil aviation are NOT "performance" engines, they are "reliability" engines. Given that they only produce 220HP with 540 cubic inches, I doubt that any flat six Lycoming or Continental would be considered a "performance" engine by our standards. If so, an engine of that displacement should have way more than 8:1 compression and make more like 600 SHP, not 220. I mean, a 502 inch Chevy does 510 HP and has a freakkin' warranty way longer than a new Textron engine - DUH!

When the top fuelers spend so much time indexing their plugs to assure one point of ignition in the precise location in the chamber for peak power, I can't understand why any of us would want to provide several. Then again, THEY change the plugs when they are worn instead of neglecting them.

9¢ wouldn't be a bargain. It's worth more to me than that in the time I spend changing them. I'd rather spend that time installing something that works better.

Just my opinion, though.

Vader

BTW - Throw a turbo on that 540-inch six and you'll get a whopping 350SHP. Add two cylinders of larger displacement and you'll make a massive 375HP with the 720 cubes.

That's what I want - 1/2 HP per cube. Even Chevy did better than that with the LG4. Must be the extra plugs, eh?

Not picking on anyone - just including the details.

StangKiller

VADER, you forgot one detail, the main reason aircraft engines have such low hp per cubic in. is that they are only rated at about 2700-3400 RPM, depending on what kind and size of propeller it's turning. But just like other engines if they had the proper heads and cam they could make some really good power because most of them have like a 5.25 in. bore!!!! You could get some pretty big valves in there. And as far as Splitfires go I had the platinum splitfires in my car for years and just changed them to plain AC plugs and didn't notice any difference in power so they can't be that bad.

Flamingo

If not splitfires, then what? I'm looking at changing my plugs soon, and am really curious what others think. And no, I wasnt planning on using splitfires anyway.

chazman

iTrader: (4)

Which $9 plug is that?

Vader

If you visit a dealer service department, OEM platinum plugs are commonly priced very close to that. Of course, they can be purchased elsewhere for about half that any day.

NGK has some very good ceramics in their program, and adequate electrodes. Champion offers pure platimums, as well as AC/Delco. Unfortunately, both of them also offer platinum clad plugs which makes the choices more confusing.

iroc22

Well my Dad has ran Splitfires in his 68 Chevy II/Nova for 6 years now and it runs fine. Ran a 13.8@100mph on a mild 327. Granted the car does see low mileage because it isnt a daily driver.

Vader

No, Splitfires probably work acceptably, but as you found, there is no effective difference in daily driving. Under extreme conditions, there probably is a difference, and it is likely biased in favor of the "regular" design plugs.

And the T/L and Connies are a low RPM engine, for sure. You don't run much past 2,600 RPM on any prop with a respectable diameter without getting cavitation - even a constant speed prop. But the engine is designed for power at low RPM, thus the huge, long stroke.

In the same manner, a Cat 3508 diesel is normally goverened at 2,100 RPM, displaces 2,100 cubes, and makes just over 1,000 HP peak. That's still about 1/2 HP per cube. With the 6-3/4" bores and 7-1/2" stroke, they have big valves, big pistons, big rods, and big everything. They are RPM limited so they don't tear themselves apart. Automotive diesels have a shorter stroke and can achieve a lot higher RPM.

More interesting, perhaps, is the truck pulling engine. Typical power band is peaking around 3,800 RPM (not much beyond the 3,400 you're talking about). They do MUCH better than 1 HP per cube, and on a lot shorter stroke.

As for an air cooled performance engine, up the compression and head flow on a 720 Lycoming flat 8, install a really lumpity cam and huge valves, and it would probably still tear itself apart at higher RPM, too. You just can't reverse that much reciprocating mass that quickly without breaking something.

It isn't all about the induction. Some engine limitations are in the basic design. A longer stroke enhances torque but limits RPM. The HP can be the same. A shorter stroke limits torque, but enhances RPM. That's why the new Chevy Indy engine (replacing the Aurora) can make 750 HP from 3.2L. It does it all with RPM, on the opposite end of the design spectrum from an aircraft engine. Still, I don't think I'd want that 3.2L V-8 under the cowl, even though I'm partial to the little engine. You just can't get out and walk at 5,000'.

None of which has anything to do with spark plug design. But try to find a SplitFire with FAA wings on it.

83CAMAROMAN

I'm not picking on anyone here either but ive been a member of this site/org for a while and ive found that Vader knows his ****....when everyone esle is arguing the trivial points.......Vader has never failed to settle the argument with concrete facts and very well-established opinion.....


just my thoughts though.....take em or leave em


shawn

chazman

iTrader: (4)

Between the AC/Delco Platinum Rapidfire or AC/Delco Professional double platinum.....which plug is better?

camaro6spd

I use RapidFires and change them every 30,000 miles...some call it over kill but that turns out to be like every 4 years on the Camaro. I can deal with that....at least i know i have good plugs in there.

Vader

The latter is that $9 plug I was talking about. Platinum center and side electrodes. You can do better at other places, however.

chazman

iTrader: (4)

Any performance/smoothness advantage with one vs the other?

Camaro_1986_19

I have Bosch Platinum +4 plugs in my 1990 Dodge Shadow 2.5 liter turbocharged 4 cylinder. I noticed one hell of a difference, I also am running Accel wires

Morley

You mean horizontally opposed? And how DARE you compare a Lycoming to a Continental? Lycoming is 10 times the engine of that other trash.

Also, the aircraft engines only have "multiple" sparks during start ie; the "shower of sparks" ignition system. Most prefer mags with impulse couplings however. BTW,We're not counting having 2 spark plugs as multiple sparks, thats a safety requirement. Also, Aircraft engines are designed for "deeper breathing" than auto engines to control detonation at altitude. Ever wonder why a plane's engine runs slobbering rich on the ground, but runs soooo smoothly in the air?

Thought everyone knew that ONE hot spark was better than a bunch of little weak ones?

Vader

Morley,

I understand. I only breached the topic because someone invariably brings up the aviation example whenever Splitfires or Bosch +4 plugs are discussed on their merits. As you apparently understand, the compariison isn't valid. Dual ignitions are simply a redundant safety in general aviation, not a performance issue.

I only threw out the SHP and displacement information to show how general aviation piston engines are relatively low performance/high reliability engines. Some aviation engines are just a lot lower performance than others. (I used to work for Textron).

As for your last statement, I couldn't agree more. That's why I always preach in favor of a single point of ignition in a precise location over the multiple-path option.

I know that some people are using these multi-path plugs with no problems. That's great. I'll still argue that the end result is no better than changing to a good quality single electrode pair. I may be the only one, but I find it unusual that Bosch and Splitfire marketing people can't afford the $120.00 for two dyno runs, one with their plugs and one with "old fashioned" plugs. That would prove their claims with quantifyable data, not opinion, testimonials, and paid endorsements. Guess what? They probably have done it, and the numbers don't support their claims, so they resort the the "Medicine Show" methods of selling the products.

Given the current battles for fuel efficiency and performance crowns among manufacturers, if there were any benefits, don't you think we'd see them on all kinds of ricers, BMWs, C-6s, and Cobras? These multi-path plugs have been available for well over seven years, so the patents have run out on the design and anyone could make and use them without royalties. So why aren't they? If we think about it a little, we probably already know that answer.