Bosch Platinum 4s

micks90lx

New Member
Sep 17, 2005
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Alaska
Well Ive been trying to figure out what was wrong with the recent engine build I did, with an all new bottom end bored .40 over to a 308 and a Trickflow H/C/I combo up top. It was running 262rwhp and 296rwtq at its best with the Bosch spwrk plugs. So I changed to some good ol cheap autolites and it pumped it up to 274rwhp and 310rwtq. I know some of you are thinking thats kind of low, but you have to know I am running that robbing clutch fan still. I figure once I put an electric fan and some underdrive pullies it should be arounf 290rwhp and 320rwtq. Oh and it just runs so much smoother now also.
 
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micks90lx said:
Well Ive been trying to figure out what was wrong with the recent engine build I did, with an all new bottom end bored .40 over to a 308 and a Trickflow H/C/I combo up top. It was running 262rwhp and 296rwtq at its best with the Bosch spwrk plugs. So I changed to some good ol cheap autolites and it pumped it up to 274rwhp and 310rwtq. I know some of you are thinking thats kind of low, but you have to know I am running that robbing clutch fan still. I figure once I put an electric fan and some underdrive pullies it should be arounf 290rwhp and 320rwtq. Oh and it just runs so much smoother now also.

:nice:,looks like we now have actual dyno proof showing just how bad Bosch Platinum +4 plugs suck.
 
a guy i work with put those in is 4 banger and swore by them. he said they made a big difference. i told him that spark was going to find the path of least resistance and those are a waste but he said the platinum make spark go to all 4. what a dumbass. this dude is a math wiz too. a computer geek.
 
Glad you got it. Plats dont conduct very well, and I wont comment on the 40-prong plugs themselves. :)

Nice work!
 
Mustang5L5 said:
Sometimes smart people lack common sense.



Bosch +4's blow ass, and i'm an engineer so take it for what it's worth.
:lol: You're slayin' me.

Mike, I can see you walkin into a meeting with a client. "Hey guys, just FYI, your design blows ass." [exit stage right with nothing else said]. :D
 
when i 1st got my car i did the tune up etc (changing plugs). When i drove by the local shop to talk to the owner about my car he was asking me about what kind of spark plugs i was using. He said for a Ford only to use autolite. He mentioned countless times how people would put Bosch plugs on a mustang and the car would run like complete crap. Stick with the autolites, and now im glad we have proof :SNSign:
 
I guess since this thread took this direction we should post symptomatic info. Plat plugs, on some EFI cars, can cause the idle to be lower. The bigger issue is that some folks see a cut-out at around 4K RPM.
 
Plat plugs can be run on certain other vehicles. A lot of cars these days come factory stock with plat plugs, but also come with upgraded ignitions and COP technology to overcome the resistance loss.

But since this is a 5.0 Mustang board, gonna have to go with what works on 5.0s. These cars did not come stock with plats, and do not have as efficient an ignition as modern cars...therefor plats just don't work right. Not only do you lose a little power, but some (myself included) expeirence detonation with plats.

Now when my grandma needs plugs for her Lincoln Continental, you'll be damn sure i'm sticking platniums in there. That car is a bitch to work on and she won't care if her motor is making 270HP vs 275HP. :)