Plugs for LT1
Thread Starter
Instructor
Joined: Feb 2000
Posts: 121
Likes: 0
From: Vandalia Ohio
Plugs for LT1
I am considering Bosch Platinum +4 plugs for my 95 LT1 engine. Installed a set in my van about 50,000 miles ago and still running great plus added performance. Will these work good in the LT1? Also, should I replace the wires with stock or aftermarket? Thanks, John
Melting Slicks
Joined: Oct 1999
Posts: 2,501
Likes: 177
From: Houston, Texas FEAR THE BONES
2023 C5 of the Year Finalist - Modified
Re: Plugs for LT1 (BowTieBlood)
I have read about too many problems with Bosch Platinum plugs in the LT1's. Most people (Corvettes and F-bodies) use NGK TR55 plugs. Cheap and reliable :thumbs:
Le Mans Master
Joined: Oct 2002
Posts: 7,178
Likes: 1
From: Bahston Mass.
Re: Plugs for LT1 (JohnOH327)
Dont do it! There are a few here that have been ok with them, but more people have had problems.
They (Bosch) replaced them in another vehicle of mine when they discovered they don't work well with modded computers... Either way, I'll never use them again.
They (Bosch) replaced them in another vehicle of mine when they discovered they don't work well with modded computers... Either way, I'll never use them again.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Plugs for LT1 (JohnOH327)
platinum plugs have a double-whammy against them. first, they're hotter than usually required for the application. second, the platinum tips/pucks are very susceptible to detonation (which will happen more readily if the plugs are too hot).
i haven't looked closely at the newer designs, but on the single electrode bosch platinums the platinum core blew out multiple times for me. it caused missing under load at wot. it took me a while to figure it out since the core is so tiny that i didn't immediately see it was missing.
my vote is for NGK TR55s.
-michael
i haven't looked closely at the newer designs, but on the single electrode bosch platinums the platinum core blew out multiple times for me. it caused missing under load at wot. it took me a while to figure it out since the core is so tiny that i didn't immediately see it was missing.
my vote is for NGK TR55s.
-michael
Race Director
Joined: Mar 1999
Posts: 16,950
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From: Stafford, Virginia Kittah, Kittah, Kittah...
Re: Plugs for LT1 (94vette)
I have read about too many problems with Bosch Platinum plugs in the LT1's. Most people (Corvettes and F-bodies) use NGK TR55 plugs. Cheap and reliable :thumbs:
I installed the standard TR55s in my Vette last night only because I wanted to try them after the rave reviews here... But I wouldn't have hesitated to put the +4s into this Vette either... The car does run better on the TR55s, but 5 of the original Delco plugs were missing the pucks and had a ~.65 gap which helps explain the increased running quality...
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Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: Plugs for LT1 (wake)
I have the NGK TRX Iridium in my 92, they are great!
When I got the Vette, I quickly replaced the AC-Delco plugs, with more AC-Delco plugs. A friend said, "use the factory part". I did... NEVER AGAIN.
I am much happier with the NGK's...
When I got the Vette, I quickly replaced the AC-Delco plugs, with more AC-Delco plugs. A friend said, "use the factory part". I did... NEVER AGAIN.
I am much happier with the NGK's...
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: Plugs for LT1 (JohnOH327)
Don't use Bosch +4's. The way the plug is presented to the combustion chamber on LT1's, LT4's, L98's the open electrode design of the Bosch +4's is not optimal. A plug with the standard design L-shaped ground strap is best. I've tried new sets of the following plugs in my '95:
1. AC 41-906 (OEM double platinum)
2. NGK TR55 v-power
3. NGK TR55ix iridium
4. AC Rapidfire #14
I like the AC Rapidfire's best. The AC 41-906 stock plug was okay, just that i was paranoid about the pucks coming off as some have reported... don't need a scored cylinder wall.
1. AC 41-906 (OEM double platinum)
2. NGK TR55 v-power
3. NGK TR55ix iridium
4. AC Rapidfire #14
I like the AC Rapidfire's best. The AC 41-906 stock plug was okay, just that i was paranoid about the pucks coming off as some have reported... don't need a scored cylinder wall.
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: Plugs for LT1 (MSR)
What evidence are you basing the increased-detonation tendency on, about the platinum pucks? I'm not calling :bs I just don't see how GM would use them as OEM if they are known to pre-dispose towards towards extra knock/detonation. Contrary to popular belief GM powertrain engineers draw on a lot of tech data and research when putting together the total package to bring to market an engine that still meets fleet average mpg requirements and EPA emissions limits yet produces industry leading (for the era) power. And Delphi, the company that OEM's most of the AC Delco powertrain control electronics and ignition components, is no slouch at R&D either. Delphi makes the various double platinum plugs for AC that are used in the LT1, LT4, LS1, and LS6 engines.
What you say may in fact be the case with double platinum plugs, but if so I don't see how it got past the aforementioned parties.
What you say may in fact be the case with double platinum plugs, but if so I don't see how it got past the aforementioned parties.
platinum plugs have a double-whammy against them. first, they're hotter than usually required for the application. second, the platinum tips/pucks are very susceptible to detonation (which will happen more readily if the plugs are too hot).
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Plugs for LT1 (Lone Ranger)
What evidence are you basing the increased-detonation tendency on, about the platinum pucks? I'm not calling :bs I just don't see how GM would use them as OEM if they are known to pre-dispose towards towards extra knock/detonation.
with the stock plugs from GM, though, then you run into the detached puck problem.
-michael
Burning Brakes
Joined: Sep 1999
Posts: 848
Likes: 4
From: Tulsa,Ok
Re: Plugs for LT1 (MSR)
Ive had the +4's in my vette going on 2 years now,and they havent missed a lick.Seen 6200-6400 rpm's a few times too :D .I like em :thumbs:
[Modified by gears, 2:10 AM 2/17/2004]
[Modified by gears, 2:10 AM 2/17/2004]
Race Director
Joined: Oct 2001
Posts: 19,653
Likes: 428
From: Melbourne Florida
Cruise-In IV Veteran
Re: Plugs for LT1 (gears)
I guess I'm the odd man out here...I put in plain old Autolite plugs last October...mine is a daily driver and I do drag race it a lot too...bought the car with Plus 4's...went to Rapidfires...now these coupled with Moroso wires...no problemo's..
Team Owner
Joined: Sep 2003
Posts: 25,295
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From: I'm the walkin dude I can see all of the world...
St. Jude Donor '03
Re: Plugs for LT1 (Fuzzy Dice)
The Bosch plugs caused a high RPM miss in my LT-1. I had them gapped perfectly too. They do not match with the Lt-1 I dont know why.
Get AC Delco Platnum's or the NGK. :smash: :thumbs:
Get AC Delco Platnum's or the NGK. :smash: :thumbs:
