Bosch Platinum Plus 4 plugs in 1998 3.3 V6

[TownShip]

Bought a mid-98 Town & Country minivan with 3.3 V6 one month ago with 60K miles, one owner, clean history verified through original dealer, CarFax and owner's original service receipts; verified primarily highway miles. Trans was serviced by dealer with out-of-warranty coverage at 52,500; now includes 12/12K warranty plus. Runs great, averaging 21.9 mpg city/hwy around rolling hills of mid-Tenn. Delighted with purchase EXCEPT one possible improvement: more power from the 3.3 V6. This was rated at 158hp for 1998 (2001 minivan models get 3.3 upped to 180hp). Ads for new Bosch Platinum Plus 4 plugs CLAIM increased performance and fuel economy. Chrysler only lists standard plug for this engine, which also has E85 (ethanol) flex-fuel capability (something that I probably won't really utilize).

??? Question 1) - Has anyone tried this plug in their '98 (or '96 -'00) 3.3 minivan or LH? What results or experiences -- good, bad, indifferent? Performance? MPG?

??? Question 2) - Do any gains last past a few months? (Several other posts have indicated results of Splitfires - as an example - diminished after 2-3 months).

??? Question 3) - Do I need to change the plug wires with the Plus 4s? I'm not drag racing - I just want a little extra oomph.

??? Question 4) - Maybe this one is for Chrysler Tech guys at CTC (or DCTC now): what impact on flex-fuel capabilities or restrictions does use of the Plus 4 have in the 3.3?

??? Question 5) - Any long term impact on the 3.3 block/heads/systems from using the Plus 4s (ie. warpage from higher spark heat)?

Maybe I'm just trying to make the 3.3 act like a 3.8 WITHOUT big bucks and decreased MPG. Other than that, I'm pleased.

Thanks in advance for thoughts, info.

- TownShip

[GR8WHT]

They are expensive and Not worth is as I have heard.
On a technical side, if the motor has just 3 coils for 6 plugs, then DON'T use the +4's

If you have a coil per plug then you can.

Why, if you have just 3 coils for 6 cylinders then 2 cylinders fire at the same time. The spark will be reversed on one of the plugs. Thus the spark goes the wrong way and will deposit on the platinum center electrode, rendering it useless.

Save your money, go with the stock plug.

[brun064]

If you want a little extra power, I've heard of an air flow restrictor inbetween the air box and the engine. Its on a previous post call "air restricotr not just for 3.5L" or something like that.

[TownShip]

I've gone back and looked at some prior posts dealing with the air flow restrictor. I year ago I picked up a Haynes guidebook on the first gen LHs, including the 3.5 first gen motor, and later the Haynes guidebook on the 96-current minivans, including the 3.3 and 3.8. I'll look at these and the air box on my T&C for this restrictor.

??? Question - does removal of this restrictor change your emmisions output levels, or does the computer adjust accordingly? Our metro area is under the EPA mandatory testing requirements. This may or may not be trivial - I don't want to solve one problem and create a new one.

Thanks for input (so far) on the plugs.

- TownShip

[TownShip]

I've gone back and looked at some prior posts dealing with the air flow restrictor. I year ago I picked up a Haynes guidebook on the first gen LHs, including the 3.5 first gen motor, and later the Haynes guidebook on the 96-current minivans, including the 3.3 and 3.8. I'll look at these and the air box on my T&C for this restrictor.

??? Question - does removal of this restrictor change your emmisions output levels, or does the computer adjust accordingly? Our metro area is under the EPA mandatory testing requirements. This may or may not be trivial - I don't want to solve one problem and create a new one.

Thanks for input (so far) on the plugs.

- TownShip

[brun064]

I don't think it would cause any large increase in emissions (but I'm not an expert). I think the only thing it would do it make the engine louder. The haynes manual probably wouldn't have anything about the restrictor since its main purpose is repair and mantainence not performance. As for the +4 plugs it wouldn't make a noticable difference unless you got a performance ignition system, but that will run you a few hundred. Good luck.

[12vDC]

Just wondering if you have had any luck finding the restrictor in your T&C.

Has any one taken their vehicle through 'AirCare' with out the restrictor in place? My 3.5 is due for renewal and needs to be tested. Should I put the restrictor back in before going for testing?

[TownShip]

Thanks for the reminder, but I have not yet had or made the time to check the restrictor. Looking forward to it, though. Thanks for insights.

I have noticed that use of mid-grade or premium fuel does indeed improve performance, in spite of what the owner's manual says (3.3 flex-fuel ECM continuously monitors fuel type/grade and dynamically adjusts engine systems). Nonetheless, am pleased with purchase. Now if OPEC would only drop the prices...

[TownShip]

Thanks for the reminder, but I have not yet had or made the time to check the restrictor. Looking forward to it, though. Thanks for insights.

I have noticed that use of mid-grade or premium fuel does indeed improve performance, in spite of what the owner's manual says (3.3 flex-fuel ECM continuously monitors fuel type/grade and dynamically adjusts engine systems). Nonetheless, am pleased with purchase. Now if OPEC would only drop the prices...

[TownShip]

Thanks for the reminder, but I have not yet had or made the time to check the restrictor. Looking forward to it, though. Thanks for insights.

I have noticed that use of mid-grade or premium fuel does indeed improve performance, in spite of what the owner's manual says (3.3 flex-fuel ECM continuously monitors fuel type/grade and dynamically adjusts engine systems). Nonetheless, am pleased with purchase. Now if OPEC would only drop the prices...