What kind of plug and plug gap are you turbo boys running? I have NGK TR6 gapped at .035-.037. Tonight I was tuning on it and leaned it out to around 11.5:1. I have been around 10-10.5. It now has a stutter/miss throught the rpm band pretty much @ wot. Any thoughts? It wasn't missing one minute then started as soon as I leaned it out a little. I'm wondering if I need to go tighter on the gap. This is on about 10psi boost. There is no knock showing on my HPT nor does it feel or sound like detonation.

 

TR6's... outta da box at .035"...

...had projects as high at 850rwhp (supercharger and twin turbo) with 18psi boost on the TR6's at that gap.

I have them in my daily driver truck too...

Fuel pressure?

Bill

 

That's what I thought to. i have a returnless fuel system. Pressure is around 61 at cruise and drops as low as 48 psi at wot. I have a MSD voltage booster on the pump set at minimum setting right now. Starts adding voltage at 5psi.

 

this is a little scary. i have seen a few posts start out this way and end up being a broken number 7 piston. most of the time the miss is down low not up high in the rpms so i have hope.

i ran tr6's for a long time at the out of the box gap. no problems at all.

how much boost are you running? how high are you spining it? whats done to the motor?

 

I will check #2 tomorrow with my boroscope that I just got in. The plug electrode was found pushed closed over a week ago but i'm unsure if it was closed before it was put in or not since a friend installed the plugs and he didnt look at them. Compression checked out ok then as well as blow by and oil consumption showing no signs of problems. I guess we will find out tomorrow.
10psi, no meth, 93 octane and about 18* timing max. miss is noticable between 2500-5k @wot. smooths out above that and cruises fine.

 

... at 54psi we would detect detonation on the dyno... thats right... a 4psi drop (depending on timing). We could turn on/off detonation with fuel pressure... that how important it is. Gotta keep the pressure up bro... somehow... someway. Depending on your goals, with a little work, you probably still have growing room with a returnless system. Heck, on the C5's I could get 625rwhp easy (6spd) before I would see a drop at around 6500 RPM on a returnless system. Actually peak torque is where maximum fuel consumption takes place... but thats another story. Its all about flow. Key is NO drop... sustaining is fine... tuners do NOT like drop... especially when it is unexpected. I could get into boost referenced return style... but that would probably be opening a can of worms not needed here...

Compression check is one thing... leak down test is another... which I do recommend as a complimentary test to a dynamic (cranking) compression check.

Let us know how it works out...

Bill

 

I promise that I won't keep this returnless system for long if I can't get it to do right really soon. GM did it for simplicity and cost i'm sure but its a pain in the *** for us. I'll get back with ya'll soon.

 

plug wire came loose and wasn't completely on the plug. easy fix.

 

It's always the simpliest things!

 

glad to hear it was a simple fix!! you always think the worst.