My friend just pulled out a perfectly good set of plugs from his Celica today and installed Bosch platinum Plus 4. There is a marked difference in the car's performance now. It's running a lot smoother and also accelerating faster than before. Now I've always been told multielectrode technology is for ricers and the like. So what's causing this car to run so much better. There must be something about the Plus 4s. At nearly $6 a pop there has to be. I believe SplitFire does truly suck because no one ever said it made their car faster. But Bosch is a very reputable manufacturer and I doubt they would put their name on something bogus.

Does anyone on this board use Bosch Plus 4 plugs? And if so, with what results? I've heard that they'll melt the tops of the pistons on a 305TPI so I stuck to regular good ole AC Delco. I wonder if it's BS or what? Vader, anybody?

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

i work for advanced auto parts why have alot of those come back on us dont waste your money

 

I just put in the A/C Delco Rapid fire worked wounders. Didn't help that the old ones had been in there forever.

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87 Z28 305 TPI, Auto, Gutted air boxes, K & N fillters, Dyno Max 3" cat back, Accel 8.8 mm spirals, and Accel coil.

 

I am running 'em now. I havent experienced any problems yet, but I believe they would be a total and complete waste w/o having some sort of capacitive dischard, multiple spark ignition system. The idea is that w/ multiple sparks, you can make several sparks in different areas, increasing your chances of comlete combustion of all the fuel. As for more power, well, My brother and a friend of his went looking for thermal/aero/mechanical enginering books that would have equations to *accuratly* describe flame front motion....there were none, in fact there was negetive response, like no one has really looked into this stuff. SO would multiple flame fronts originating from slightly different spots of the spark plugs really help? I dunno! Find someone w/ a lot of cash and a dyno, and replace the plugs and check for the difference, if any.
Corry

 

Actually, i can kind of see why the celica might make a hair more power with the +4s. I'd guess that it has some sort of OHC motor in it, with the plugs going straight into the top of the head. The +4 is perfectly indexed for such a configuration, with no occlusion of the flame front from the ground electrodes, since they are on the sides. I don't think that having 4 electrodes is helping much, but that they are open to the bottom is. Of course, this means nothing to us, cuz our spark plugs are practically perpendicular to the stroke, so careful indexing would be needed to get the same effect.
It's the same principle as the extra couple HP you could get from cutting back the ground electrode on a regular plug.
...ed

 

Actually, my car felt better with the Splitfires, especially over the Accel U-groove's.

 

i put the +4's on my car and noticed that the idle was a lot smoother, but i didn't notice anyting else.

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1987 Trans Am
Black & Gold
Light Mods

 

Yeah Ed, the Celica has an OHC motor. The plugs go in straight from the top. Sounds like a plausible explanation to me.

About the multiple spark thing, does anybody make such ignition systems for our cars? If so, are they any good?

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

I have a couple of questions about plugs like that. 1)How do you gap them accurately. particularly after they a worn a bit?
2) Since electricity follows the path of least resistance, how can you predict which electrode is firing and when?
I think it is one of those ideas (at least for our application) that is better on paper than in the real world. Ill stick with my AC's.
I do find that explanation regarding the OHC engine interesting. Old Mazda RX7's came with a multielectrode plug like that.

 

Ive used them before and havent had no problems with them, they seemed to work great, but the ACDelco Rapid Fires work the best on our cars.

 

it says right in the bosch catalog that those plugs shouldnt be gapped

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350, Comp 262, Edelbrock Performer intake 600 cfm carb and exhaust, headers

 

The box says they're pre-gapped and don't ever need to be adjusted again. Those of you who have seen these plugs might have noticed how thin the center electrode is too.

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

I was just discussing this with my buddies today and basically we all came to the same conclusion that they're just an advertising gimmick. The price doesn't justify the minimal gains people are getting from them...I'll stick to my rapidfires as well

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82 Z28
355 carb'd, Edelbrock Performer RPM package (minus heads), Hooker Super Comps, Mufflex 4" offroad y-pipe, 700r4 with B&M shiftkit, '85 IROC 10 bolt rear with Richmond 4.10's & Auburn posi unit, Lakewood 50/50 drag shocks. Shooting for 3000lbs w/ driver.

The car's website (New design in progress...very cool look)

(383/TH350 buildup this winter)

AIM: Unitedhope
ICQ: 77979548

 

Rapidfires are not cheap either, but so many people are using them so I guess they do work.

One question - what difference did you guys feel with Rapidfires over regular AC Delco R45TS plugs? I'm wondering whether I went the right way with R45TS.



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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

MSD, ACCEL, Crane and Jacobs all make systems for our cars. The most worry free is MSD in my book. Had mine on for 4 years with no problems. You will need the tach adapter so your tach will work properly. You won't notice so much as a power increase as you will throttle response or gas mileage. It may be noticed if you went from a stock to MSD if you had a hi-po motor. Every little bit helps. Go with a hi-output coil also. ACCEL makes a high performance module for your distributer that allows for longer dwell times which would also accomadate the new ignition. The MSD 6A or 6AL boxes are reasonably priced and the only difference is the 6AL allows you to set a rev limiter which is nice if you have a manual.



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1988 TA 300+hp 350 w/ TBI and Holley TB unit, Holley projection intake,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip

2000 Kawasaki KX 125

 

I'll buy Ed's explanation (Ed's wisdom hasn't let us down yet) but the multiple spark thing is bunk. Electricity follows the path of least resistance. Even if all 4 electrodes are the exact same size and distance from the center electrode, after the first flame front passes by the electrodes, a minimal deposit will be formed. This will immediately divert the electricity through the cleanest of the 4, and that will continue to be the only electrode doing jack squat for the remainder of that plug's life. The other 3 will continue to sit there doing nothing because they have a resistance that is .00000000001 ohm higher because of the additional deposits on its surface.

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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

I put them in my car. I was using NGK plugs before. I didn't really notice a difference at all. It was a whole lot of money for nothing, as far as I see it.
Vman

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1989 Camaro RS
2.8 V6
K&N's
700R4 tranny
Cragar Street Pro rims (old Series 30)
Pioneer DEH-P3000

1969 Camaro SC
350 HO from a Vette
Turbo 350 tranny
In the process of being restored

 

I remember another friend's experience with Bosch plus 4s in his Vtec Civic. The Bosches actually decreased power. Acceleration went waaay down. He switched back to the NGKs he originally had and all the power came back.

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

I work for Kragen Auto Parts (same as Checker, Schucks) and at 6 bucks a piece i dont even buy these with my employee discount. in fact i wouldnt even steal these plugs. Rapid Fires are for me. :-)

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Rick
90 Camaro RS 305 TBI
350 on the way!!