I got to stick up for Bosch. Some people say Bosch products suck. Well if bosch products are put in almost every new car it must be for a reason. There plugs are the best too. The A-4 plugs are even better. I could notice a difference when I first put them on. It idled better and got better gas milage and throttle response. Basically what ever Bosh makes is top noch. I used there 02 sensors too which are better that Delco everytime.

 

Not saying that you don't know what you are talking about, but... YOU DON'T KNOW WHAT YOU ARE TALKING ABOUT... Now many of Bosch's products work and work very well. Their jigsaws are the ****. My father has a Bosch jigsaw that has been around almost as long as I have and works just as good today as it did new.

Their +2 & +4 plugs, on the other hand, are A GIMIC. There is no way (after acouple hundred miles) that these plugs would outperform the $2 *insert your favorite plug manufacturer* copper plug. I'd rather replace my plugs every year for $8 total (yup that's what the 1 heat range colder NGK plug set costs for my Bonneville) than have a gimic plug that costs that much for one.

And to say that they improved your gas mileage and blah blah blah... Well if you had bad plugs with oversized gaps and replaced them with a $1 plug, you'd probably notice the same increase. Heck, you could probably re-gap the old plugs and have the same increase.

I don't know how many times I have to say this, but from an electrical standpoint, the spark will take the path of least resistance. As the plug gets used, one preferred path will get the spark while the other ground straps would become carbon covered and would not clean themselves due to the lack of heat (lack of spark). Not to mention that my brother has tried them in his old Jeep with a I-4... They did do better than the crapped out plugs that came out, but when I pulled them afew months later, only 1 ground strap was clean. The other 3 were carbon'd over. It was VERY apparent that it was only firing on one of the 4 straps... A new set of NGK copper plugs showed the same noted improvements.

Not to mention that your 'butt dyno' means absolutely nothing. My Bonneville feels completely different on a cold/dry day than it does on a warm/humid day. Spark plugs are spark plugs. If an Indy car uses a single electrode, then you don't need anything better... Well, ok, and Indy car isn't a good example because they don't have a ground strap, they use the top of the piston as the ground electrode for the spark to jump to. So a better example is NASCAR. 800hp small blocks that use normal 1 electrode plugs. Why wouldn't they use a 4 electrode plug? Because it doesn't work as advertised.
And exactly how many times have you used Bosch sensors vs Delco sensors? Please answer that question. I have replaced Bosch sensors more times than I can count on all of my fingers AND toes. Each one that I have had to replace was less than 2 years old when Delco's that I have put in were still going strong MANY MANY years after the fact.

Many times, the Bosch O2 sensors will do just as well as AC Delco's in GM applications. However, the major downfall is that the Bosch sensor will not last anywhere near as long as the Delco. Also, I can show you scans where the Bosch O2's are less active out of the box brand new than an AC Delco in the same car ('97 Caddy STS 4.6L Northstar) with tests minutes apart (if I can find the files). I'll even go so far as to do it on my Bravada with brand new sensors just to prove this point.

When you go making blanket statements like this with NO background is when I get mad. FYI, I grew up on a farm were we fixed everything ourselves. I have been working on cars, trucks, tractors, and tractortrailers since I was 8 years old. That gives me 18 years of experience with a vast variety of engines, transmissions, etc. I've known how to weld since I was 11. I built the engine in my Chevelle when I was 14. And you? This is not to toot my own horn, but to lend to how qualified I am.

*EDIT* - editted to remove comments that just came out wrong

 

Oh and please state what new cars get the Bosch O2 Sensors... GM uses AC Delco sensors and many times, these sensors last for 5+ years. Some other manufacturers use Bosch and for their designs, they probably last that long. For GM vehicles, and the last time I checked that's what we all drive here, AC Delco is the way to go. I have seen it too many times where someone has bought the Bosch sensor because it was $20 cheaper only to replace them a year or 2 down the road with the proper sensor.

 

Not that I claim to know more Kyle, but I DO know that the recommended plugs for Volvos are Bosch Platinum. Now whether or not that means they are the BEST, just because they are recommended is a question to be answered. Volvos are fitted with Bosch from the factory, but it may not mean they are the best. I can say that I never had any complaints when I drove my Volvo.

This is from this website:

For years there has been a lot of contradictory information surrounding
the results of using Bosch Platinum spark plugs. These myths and legends
had bled over into Volvo 850-dom, which I found odd, as the 850's engine
management system is by Bosch, and also because they worked so well for
me! Further, even after I'd proclaimed the Bosch Platinum plugs fit for
(even severe) service in my 850 Turbo, it seemed like some owners of these
cars had a remaining aversion to or doubts about Bosch Platinums, likely
due to lingering doubts over these persistent myths and legends and
mechanics' tales.

After a bit of digging, I came up with a phone number for Bosch technical
support: 800-521-5462


I will now attempt to debunk for you the myths and legends surrounding Bosch
Platinum spark plugs:

Bosch acknowledges a problem with using their Bosch Platinum spark plugs
in engines with ignition systems that employ 1 coil for each pair of spark
plugs (also known as a "waste spark ignition system").

In cars with conventional (1 coil, distributor/rotor) ignition systems
(including the 850 Turbo with Bosch 4.3, 4.4 engine mgmt systems), there
is no problem. In fact, not too surprisingly, according to Bosch, the
maker of the 850's engine management system, the recommended plug is the
Bosch Platinum FR7DP, which is what passed with flying
colors my tests-under-fire in my engine.

The problem that Bosch has acknowledged when using their Platinum plugs
in engines with waste spark ignition systems stems from the tendency of
electrode metal to get transferred depending upon the polarity (direction
of current flow) of the spark. In waste spark ignition systems, 1/2 of the
plugs always see reverse polarity sparks. Given the very narrow platinum
center electrode of the Bosch Platinums, performance will be degraded more
significantly when reverse polarity sparks will cause material to be
transferred from the large ground/outer electrode onto the narrow platinum
center electrode's exposed end surface.

In cars with conventional (1 coil) ignition systems, every spark is of
the same polarity, for which the Bosch Platinums are optimized, leaving
them to deliver their designed-in advantages, which include:

- reaching self-cleaning temperature faster ("than any other plug")

- maintaining the spark gap and low firing voltage requirement throughout
their service life. (even in my high-stress turbocharged application)

While there remain some cars with conventional ignition systems which
do not seem to get along very well with Bosch Platinums, which seemingly
no one can explain (maybe all their sparks are of the 'wrong' polarity
in some cases), they did and do good work in my '95 854 Turbo.

Now, of course this may not be relevant to Blazers, but I do think that it is relevant in the Bosch debate. Maybe they are ****ty for Blazers but not for Volvos...

My opinion? I think that everyone has their preferences just as people have preferences with vehicles in general. Some people, like the people in here, obviously like GM made vehicles, or they wouldn't own their Blazers or Jimmys in the first place. And like Kyle said, last time he checked, that's what we all drive around here.

I also have to say that Kyle is right in arguing the fact that Bosch couldn't possibly make EVERYTHING top notch. You can't be the b

 

I am in no way saying that the bosch platinum plugs are bad. The only product that i have bashed made by Bosch is the +2/+4 plugs and their O2 sensors for GM applications. I have successfully used Bosch O2s in Dodge vehicles in the past and they have lasted. My stance on Bosch O2s will always remain the same when it comes to GM vehicles. In other threads I clearly stated this. This post just raised some hairs.

 

I understand. I hate it when people make statements and don't back it up. I'm a Platinum fan, but that's it, so I agree with what you are saying. But I'm still sticking to Delco for the Blazer.

 

I put the Delco double plats back into my Bravada, but I took the platinums out of my Bonneville the day after I bought it in favor of regular old coppers (albeit 1 heat range colder). The coppers handle the boost much better than the platinums do. As I mod that engine, I'll have to drop the heat range further to keep things proper.

 

I would also like to add that Bosch Platinum plugs are not a good application (well any platinum plug for that matter) in the Dodge 3.5L 24valve v6 used in the 93-97 Intrepids. This is exactly because of the wasted spark spoken of in Moon's first post. The reverse spark kills platinum plugs QUICK!

 

A-4 last upto 60,000 miles. What do Delco last upto. And for o2 sensors I just replaced the stock ones which were Bosch. Maybe your cars are just too old lol. All import cars use bosch and now most exports. Just like you said swart bosch is a respectable name and company. Delco's are good for applications of high demand but stock applications bosch runs circle's around them. Oh Bosch o2's are more expensive than delco I just replace mine 53 bucks each. I did not know anything about that stuff moonwater quoted but my plugs work great on my car. I get 25 miles highway for a reason and will be getting more soon.

 

Hey, take a look at my sig there champ. The only car that I own that is older than your Blazer is my Chevelle which doesn't have O2 sensors. And the Bosch sensors are NOT more expensive than the AC Delcos. My Delcos just cost me $72 each from an AC Delco retailer in town. They'll cost you $130+ at the dealership and around $60 from online sources + shipping/handling. KNOW your facts before making statements.

Your mileage depends on where you live (climate, geography) and how you treat the gas pedal. I can get 28mpg with my Bonneville if I drive like an old lady. Big deal! Good for me! YEAH!!! YAY!!! I got 20mpg with my Bravada all loaded up driving 80mph on the thruway with tons of hills. Good for me. My mods are... Air in my tires, new AC Delco Double Platinum plugs, new plug wires, blah blah blah, not to mention an AWD system that saps atleast 1-2mpg with the extra drag... And it's not because of so called 'mods' like a tornado or Royal Purple oil. Oil is not a mod btw. And I don't even have an intake or exhaust on. WOW, I must have a factory fluke!

You still haven't answered my question about how many O2 sensors you've replaced?...
My opinion (and it's just that) has been based off of actual scans of sensors SIDE BY SIDE. In EVERY case that I have come across, the Bosch sensor has not been as active as the Delco, PERIOD!

Your Blazer DID NOT, I repeat DID NOT, come with Bosch O2 sensors. It came from the factory with AC Delco's (AFS105's up front). If you replaced a Bosch, then they had been replaced prior to you purchasing the vehicle. If you haven't had the vehicle since new, then you know NOTHING about it's past. I haven't owned my Bravada since new (actually just picked it up at the beginning of the summer), but I can tell you that the O2s that I had replaced acouple months ago were Delcos (probably factory). That means that they lasted (and were still doing a good job w/ no codes) for 5 years and 75,000 miles. Show me a Bosch O2 in a GM application that can last 1/2 that! Good luck