Dont waste your money on plugs and expect to see HP gains. 
Bosch Plat+4 = HP increase
Thread Starter
Pro
Joined: May 2004
Posts: 551
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From: Morgantown WV
Bosch Plat+4 = HP increase
This months Corvette Fever Mag article in Tech Line page 82 makes the statement that Bosch Platinum Plus 4 Spark Plugs will add 6-8 HP. Can anyone substantiate that claim? 
Team Owner
Joined: Jul 2004
Posts: 24,652
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From: NJ
St. Jude Donor '05-'08
yeah maybe over fouled plugs.
I use NGK in my car and motorcycle and they seem to work just fine. I used Bosch Platinums in my Porsche and I did not see a difference...
I use NGK in my car and motorcycle and they seem to work just fine. I used Bosch Platinums in my Porsche and I did not see a difference...
Last edited by Wicked Weasel; Jul 13, 2005 at 08:27 PM.
Burning Brakes
Joined: Feb 2001
Posts: 936
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From: Reston VA
Spark plugs will not add HP but keeping them in good condition will prevent you from losing it. I use the +4’s because they’re long life, don’t require gapping and won’t blow out during sustained high speeds. – C.
Race Director
Joined: Apr 2001
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From: Saint Augustine, FL
Mid-TN Events Coordinator
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
I did those +4's in my old 93 LT1. WORST mod ever. Rough idle, bad gas mileage, etc...I pulled them out after a few hundred miles. I then found the PN#'s matched the plugs in my 99 Tahoe so I threw them in there thinking it was just a fluke with the LT1. The Tahoe ran about the same, but the gas mileage went down 2 MPG. Never again.
Don't waste your money.
Don't waste your money.
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Burning Brakes
Joined: Apr 2005
Posts: 753
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From: Oceanside CA
Originally Posted by AJay
This months Corvette Fever Mag article in Tech Line page 82 makes the statement that Bosch Platinum Plus 4 Spark Plugs will add 6-8 HP. Can anyone substantiate that claim?
Racer
Joined: Apr 2005
Posts: 315
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From: Johnstown PA
I use Plat +4's, I've had now problems...I agree you wont see any HP gains, but they seem to run smooth and have a long life. I got them on sale so they weren't really that expensive. Overall I'm satisfied. (However, I did upgrade the wires to MTD 8.5mm supers)
Race Director
Joined: Apr 2003
Posts: 19,352
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From: Tampa, Florida
Didnt the mag substantiate the it themselves?
I have them in my 2003 C5. Idle is smoother and they last a long time. It was the best mod I did to my '94 C4. Not the exhaust wires or intake. It was the +4's.
I have them in my 2003 C5. Idle is smoother and they last a long time. It was the best mod I did to my '94 C4. Not the exhaust wires or intake. It was the +4's.
Drifting
Joined: May 2003
Posts: 1,715
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From: cAshburn VA
Been running the +4s in the c5 for 3 years now. Zero issues. Can't swear to any power gains, but they were much better than stock. 400rwhp for a cam only, and a mild cam at that, I sure ain't losing any power with them. Running them with Taylor wires and koolsox.
I liked them so much I put a set in my 90 Jimmy (full-size), OMG, what a difference.
Not an expert, just my $.02... Good Luck!
I liked them so much I put a set in my 90 Jimmy (full-size), OMG, what a difference.
Not an expert, just my $.02... Good Luck!
Safety Car
Joined: Sep 2003
Posts: 3,558
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From: Cape Coral FL
Originally Posted by SGT. PYLE
It's true! And the hood seal will add 15hp for a total of 21-23RWHP. LOL!!!
Drifting
Joined: Jul 2002
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From: Spring Tx
Actually Ive seen significant increases on dyno tests with Denso Irridium plugs on forced induction applications.Doing a google search and there seems to tons of evidence that these plugs are good for at least 1 hp over even the vaunted ngks in normally aspirated applications.No I'm not going to dump my $6 ngks for $12 Densos
Team Owner
Joined: Apr 2001
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From: S.W. Ohio. . . . . . NRA Life Member
Bosch Plat+4 = HP increase
I then put in the Delco Iridiums and it hummed like a precision instrument.
Guy at AutoZone kinda laughed at me when I returned the Bosch +4 plugs... saying that the Bosch is too cold for a stock LS1 motor, and that changing to bigger diameter plug wires is a must with them.
I would of never believed this unless I had seen it with my own eyes.
