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I recently had my 60mile tune up and decided to change my plugs to boshe 4's. I have noticed a large power loss and change in noise from the exaust. does anyone if it could be the plugs? is it worth it to change them again? if so what should i change them to?
thanks
 

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Yes. they are shit. Take them back..

Seriously.. it has been proven many times that our cars only run well on stock NGK Platinum plugs. the only exceptions are HKS plugs and Denso Iridium's.. those work well too from what I've heard.
 

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I put Bosch Platinum +4's in my 1994 VR4 and quickly noticed problems under hard acceleration. The gap is larger (as I later learned) and not adjustable. You get spark blow out under high pressure.

I took them out, put in new NGK Platinums and the problem was immediatley solved.

I'll never use them again.

Chris
1994 VR4
 

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The Wizard Of Aaahhhhh's
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I too made the mistake of using Bosch Platinum plugs. Never again will a Bosch plug see inside my combustion chambers.


Chris
 

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3.2.1.....Go!
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The guy that I bought my VR-4 from said that the car came with a factory fuel cut to preserve the turbos. Took the plugs out and noticed that they were Bosche and what he thought was fuel cut turned out to be spark plug blow out. I would only buy NGK as I have heard poblems with Denso and turbo cars.
 

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Vr-4 Evr
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DOCRADLEY said:
I put Bosch Platinum +4's in my 1994 VR4 and quickly noticed problems under hard acceleration. The gap is larger (as I later learned) and not adjustable. You get spark blow out under high pressure.

I took them out, put in new NGK Platinums and the problem was immediatley solved.

I'll never use them again.

Chris
1994 VR4

With that in mind an upgraded ignition will make the BOSCH's work perfect
 

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Since the gap of the Bosch +4's is not adjustable why would you go to the trouble of upgrading the ignition only to have the plugs be a potentially limiting factor. You might still need to adjust the plug gap to for optimum results and you wouldn't be able to.

I tried them when my car was stock so I assumed that the plugs had a correct gap for the car. I got them because I needed to change the plugs and these were readily available locally (plus I bought into Bosch's hype).

If you're upgrading the ignition you've already modified other attributes of the car, why not use the NGK or Denso Platinum's or try Denso Iridium's if the issue is you want the long plug life (but still can adjust the gap if needed). If it's cost you can use coppers. I can't see the point in fooling with the +4's.

Chris
1994 VR4
 

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Quick VR-4 said:
The guy that I bought my VR-4 from said that the car came with a factory fuel cut to preserve the turbos. Took the plugs out and noticed that they were Bosche and what he thought was fuel cut turned out to be spark plug blow out. I would only buy NGK as I have heard poblems with Denso and turbo cars.
hah - thats sweet! nice to know the car wasn't run too hard before u got it :D

.jon
 

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I put Platinums in my car once... my first heavy acceleration at like 17psi killed the plugs. Never going near them again.

If you don't mind changing your plugs every couple months, get the NGK Coppers. Dynamicracing.com and probably some other places has the lower heat range set (good for a little more boost) for like $9.25/each after the shipping is added in. If you're pretty much stock and don't race much, the platinums will be great too, I've found (as have many others it seems) that they just don't hold up to high boost as much, platinums are more for longevity, copper is for performance.
 
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