Sparkplugs help BPR6ES and BPR7ES *MUST KNOW*

[oVer-Boostin]

Hello All

I have a 97 gst spyder.. Mods are: Garrett ported T-28 turbo, 3" full exhaust, and a boost controller boosting at 12psi.

I got the car running rich and it had NGK Bpr7es in it. It smoked a lot as well as a but of fluttering at high rpm. After a bit of research I found that Bpr7es sparkplugs maybe too cold for my minor setup and at only 12 psi so I decided I would switch to Ngk Bpr6es sparkplugs. I went ahead and put a brand new set of the 6es's in, let the car warm up for a few minutes then I took it for about 10-15 minutes of hard driving. The car idled great maybe even better than the 7es's. However, the fluttering was still there. It feels almost like fuel cut at high rpms during 3rd or 4th gear pulls. I took pictures of the 7es's as well as the 6es's right after the test drive. They are still pretty white and I was wondering if that means I am running lean compared to the dark black 7es's which show that I was running rich. Any input is appreciated it. Please scrolls down for pics.

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[crimsondragon]

The 6's are perfect for your setup. The white is just residue from the burn. Stick with them. Use macro on your camera next time.

 

[hectorjr]

White is okay but black is not. My n/t is running lean right now and the spark plugs are scorched from the tips. Lean messes up is the gas mileage. Are your sp wires good? what about your o2 sensors? o2 sensors play a big part in the way the spark plugs are lookin.

 

[oVer-Boostin]

Sparkplug wires look good, they should be good. O2 sensors are new. I wonder if running 12psi on a ported garrett t28 turbo is too much for a stock fuel system?

 

[meliketoball]

I would either get an upgraded fuel pump or maybe possibly turn down the boost to around 8-9 psi.

 

[Boost92awd]

You cant run that low of boost, you can only run off the wastegate for lowest boost, which will be stock boost.

 

[91 Turbo Mitsu]

Sparkplug wires look good, they should be good. O2 sensors are new. I wonder if running 12psi on a ported garrett t28 turbo is too much for a stock fuel system?

Dont ever trust how the plug wires look. I had a set that was brand new and when we ohm'ed them they were off the scale for resistance. Ohm your wires and see if they are within spec for your application. Dont ever trust how they look and from my experience dont buy cheap wires buy the best ones you can afford. Just my .02

 

[MrBoxx]

Have you done a boost leak test yet?

 

[DSMunknown]

Eric, you're turning into Bruce.

 

[T is for TURBO]

I would either get an upgraded fuel pump or maybe possibly turn down the boost to around 8-9 psi.

I ran 16 lbs on a big T-28 with stock fuel system (6 bolt long block with stock 6 bolt compression) so I think he's okay at 12.

Fuel cut is most likley a boost leak

Can you further describe the fluttering? Is it when you let off the gas?

 

[oVer-Boostin]

Maybe a Boost leak but I dont know where to check. Could it possibly be my stock 2g bov?

Fluttering happens at WOT. Say im punching it...get to 5500 rpm, it will spike down to 4500 then 5000 then 4500 again so on...

 

[turbosax2]

Your stock bov could be a boost leak spot. Do you know how to do a proper boost leak test?

 

[T is for TURBO]

what he said. 2g bov suck, especially after they get older. Do a boost leak test to find out for sure

 

[oVer-Boostin]

I dont have a boost leak tester. Is it possible to do a boost leak test without the home depot made boost leak tester?

 

[layzie12g]

Yes you can use a homemade tester and it works well. To me it sounds like a boost leak or plug wires. I thought my plug wires look good too but one was bad and the car ran like sh*t and higher rpms. I fixed that and problem was gone.

 

[Diplomat]

Dont ever trust how the plug wires look. I had a set that was brand new and when we ohm'ed them they were off the scale for resistance. Ohm your wires and see if they are within spec for your application. Dont ever trust how they look and from my experience dont buy cheap wires buy the best ones you can afford. Just my .02

+1

A lot of guys ignore their plug wires when troubleshooting an ignition hiccup because their outward appearance is often deceiving. Don't overlook them and you might save yourself some headaches.

 

[meliketoball]

Alright you guys win about the t28 with stock fuel package but next time you should do it all at once!!!

 

[snowborder714]

I dont have a boost leak tester. Is it possible to do a boost leak test without the home depot made boost leak tester?

Nope. You need a tester of some sort. Just go buy the parts and build it. It'll cost about $10 and 15 minutes to build.

IC Pipe Tester

 

[DSMunknown]

Or if you're a lazy douche, you can buy one here.

 

[oVer-Boostin]

I am a lazy douche. Good news though. Did a compression test last night...results were 160 152 152 155

 

[kenamond]

I agree with your plug selection, but did you gap them correctly?

Cooler plugs will ... well ... run cooler. At 12psi boost, the combustion gasses don't get as hot, the 7ES plug conducts too much of that heat out of the plug tip and into the head. The plug gets too cool and doesn't burn off carbon deposits. So soot builds up on the electrode and it fouls. The 6ES plug conducts less heat from the plug tip to the head, so at 12psi it runs hotter than the 7ES and burns off the deposits.

And 12psi on a T28 should be just fine.

And I can get 9psi on my FP B28 at min boost level (MBC completely loose). Shorter vaccuum lines might get you lower than 9psi. I assume the FPB28 WGA is the same as a T25 and T28, but that might not be the case.

So check plug gap, plug wires, do a boost leak test, and fix all the leaks you find (all of them).

 

[hintouring]

i know this is a couple months old but damn no one said anything about gapping the spark plugs to .28

 

[DSMunknown]

i know this is a couple months old but damn no one said anything about gapping the spark plugs to .28

You would never want to gap any BPRXES spark plugs to .28 inches. Gapping them to .028" (with a .001" handicap) would be more effiective. BTW, Mack already elluded to appropriately gapping them - see above.

 

[MPDano]

Great thread. I like the Home Depot Boost Leak tester. Gonna make one this weekend!