Bosch plus 4 spark plugs?
07-10-2018, 04:23 PM
#1
Racer
Thread Starter
Bosch plus 4 spark plugs?
On my 96 LT4, I pulled off one of the wires to see what kind of plugs it has and found it has bosch plus 4 plugs. Are these plugs garbage? The runs good with no issues but I'd thought I'd see AC Delco plugs and not Bosch.
Last edited by turbobuick33; 07-10-2018 at 04:24 PM.
07-11-2018, 09:04 AM
#2
Drifting
In general they are just a good marketing campaign. Most people see more ground electrodes so they automatically think it is a superior plug. However all that extra ground electrode material absorbs heat which could otherwise be used as energy towards the gas mixture. Ultimately that effects ignitability. There is an argument for the Bosch 4 in terms of carbon fouling but that shouldn't be an issue for you.
You'd be better off with a single fine wire plug, there is a reason all OEM's today use this type of design.
You'd be better off with a single fine wire plug, there is a reason all OEM's today use this type of design.
07-11-2018, 08:53 PM
#5
Racer
as an ex Robert Bosch factory rep and the winner of a national sales contest selling spark plugs (signed up Wal Mart) , I run NGK in the LT4. on a side note ,while at a plug factory in Germany, yellow ACCEL "racing plugs" were rolling of the same production lines as the Bosch. at the time production cost for a standard plug was 6 cents ea.and sold them by the box car load for 30 cents ea. AND...for 70 years the only metric part on an American vehicle was the spark plug. the reason ? Robert Bosch invented the spark plug. Now you know.
07-12-2018, 12:19 PM
#6
Pro Mechanic
Pro Mechanic
You found Bosch plugs in your LT4 because, at some time in the past, someone took the stock ACDelcos out and installed Bosch. The Bosch Platinum Plus 4 spark plug is not OE in any engine. It solely an aftermarket product and is a big dose of marketing BS.
One situation which contributes to the ignition process is how much of the charge air and fuel are exposed to the spark. The better that exposure, the better the quality of ignition.
Now let's add three more ground electrodes to the spark plug. What do you think that does to how the charge air?
For 19 years I owned a C4 ZR-1 and my spark plug of choice was the Denso IT-22. For the LT4, I'd probably use the IT-20. Both have just one cut-back side electrode.
One situation which contributes to the ignition process is how much of the charge air and fuel are exposed to the spark. The better that exposure, the better the quality of ignition.
Now let's add three more ground electrodes to the spark plug. What do you think that does to how the charge air?
For 19 years I owned a C4 ZR-1 and my spark plug of choice was the Denso IT-22. For the LT4, I'd probably use the IT-20. Both have just one cut-back side electrode.
07-12-2018, 05:16 PM
#7
Racer
Thread Starter
Yes, I know Bosch is not a OE plug. The previous owner did replace the plugs yrs ago but he didn't remember what plug the shop installed. That's why I was curious and pulled the wire off to see what kind of plug was in there.
I've read several threads of the Bosch plus 4 plugs being both good and bad. Some engines do run well with these plugs and some don't.
I've read several threads of the Bosch plus 4 plugs being both good and bad. Some engines do run well with these plugs and some don't.
Last edited by turbobuick33; 07-12-2018 at 05:16 PM.
07-12-2018, 08:42 PM
#8
Melting Slicks
NGK TR55's is whats going into my newly acquired LT4.
07-12-2018, 08:55 PM
#9
Team Owner
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Co-winner 2020 C4 of the Year - Modified
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My tuner told me all those sparks plugs (Bosch) are crap. The downside of the NGK TR55 is they last 20-25,000 miles.
STAY AWAY FROM THOSE E3, they are crap-crap-and crap. I used them long ago in my DD and the poor 4-banger lost like 20 horses.
I use TR5 in The Ghost, my plugs are gapped to 0.035.
Last edited by PLRX; 07-12-2018 at 08:59 PM.
07-12-2018, 09:54 PM
#10
Racer
Thread Starter
07-12-2018, 10:00 PM
#11
Melting Slicks
I got a 96 CE with 40k miles.
07-13-2018, 10:12 AM
#12
Racer
07-13-2018, 02:02 PM
#13
Drifting
You found Bosch plugs in your LT4 because, at some time in the past, someone took the stock ACDelcos out and installed Bosch. The Bosch Platinum Plus 4 spark plug is not OE in any engine. It solely an aftermarket product and is a big dose of marketing BS.
One situation which contributes to the ignition process is how much of the charge air and fuel are exposed to the spark. The better that exposure, the better the quality of ignition.
Now let's add three more ground electrodes to the spark plug. What do you think that does to how the charge air?
For 19 years I owned a C4 ZR-1 and my spark plug of choice was the Denso IT-22. For the LT4, I'd probably use the IT-20. Both have just one cut-back side electrode.
One situation which contributes to the ignition process is how much of the charge air and fuel are exposed to the spark. The better that exposure, the better the quality of ignition.
Now let's add three more ground electrodes to the spark plug. What do you think that does to how the charge air?
For 19 years I owned a C4 ZR-1 and my spark plug of choice was the Denso IT-22. For the LT4, I'd probably use the IT-20. Both have just one cut-back side electrode.
NGK TR55 plugs use a copper center electrode which wears quickly. Platinum plugs last longer than copper and iridium plugs last longer than platinum. Usually iridium plugs have the smallest diameter center electrode which have an advantages with a lower required discharge voltage and more area for the flame kernel to propagate.
Most people will argue that copper plugs are best for performance, but plug technology has come a long way and current iridium based plugs offer performance and durability.
07-13-2018, 02:44 PM
#15
Thx to you guys, I decided to double check my plug gaps and found they were WAY out.
Acdelco 5 plugs were re-gapped to 0.035 and completely changed the car.
Thanks again
Acdelco 5 plugs were re-gapped to 0.035 and completely changed the car.
Thanks again
Last edited by clove86; 07-13-2018 at 02:44 PM.
07-13-2018, 06:26 PM
#17
Le Mans Master
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I tried those those once and the car immediately felt like a dog, I double checked them, swapped etc never got them really working.
AC Delco Platinum: Thats what I run as well, nothing fancy, works for me. I’ve run the Bosch Platinums (non plus 4 versions) without issue as well.
AC Delco Platinum: Thats what I run as well, nothing fancy, works for me. I’ve run the Bosch Platinums (non plus 4 versions) without issue as well.
08-13-2018, 10:08 AM
#18
Yes, I know Bosch is not a OE plug. The previous owner did replace the plugs yrs ago but he didn't remember what plug the shop installed. That's why I was curious and pulled the wire off to see what kind of plug was in there.
I've read several threads of the Bosch plus 4 plugs being both good and bad. Some engines do run well with these plugs and some don't.
I've read several threads of the Bosch plus 4 plugs being both good and bad. Some engines do run well with these plugs and some don't.
08-14-2018, 04:42 PM
#19
Team Owner
Not necessarily. Just because it runs doesn't mean anything in this context. If it costs more, it has to do something more. I think it is foolish to pay more for the same or less. I'll pay more for a set of say Duralast Gold brake pads than the cheap Duralast ones. OTOH, I also expect it to do something more than the Duralast ones. Just because my car stops well on the Gold ones doesn't mean squat. I paid more, I expect more.