I installed a G5X3 cam in my Z06 over the weekend and had it dyno tuned yesterday. I'm running LG headers with cats and all the bolt-ons. I pulled a dissapointing 363 rwhp and 330 ft-lbs tq. So I found the problem today and it turns out that cylinder #8 was dead. The pushrod had come off the rocker arm so one of the valves was close up all the time. So my car was tuned on 7 cylinders. Here's my problem....

The car runs terrible now and is sluggish. I drove it one mile down the road and pulled over because I smelled smoke. It turns out my cats were cherry red I let it cool down and drove it home. When I got here the cats were again cherry red. I know cats are supposed to get hot, but not that hot. Something is definetly wrong. What gives?? Any advice?

 

Did you retune it after you fixed the #7?

 

360hp and 330ft-lbs is great on 7 cylinders.....Alot of people don't make that power with 8 cylinders

 

Sounds like that cats were full of fuel from no combustion in 1 cylinder, what I cant figure out is how your tuner didn't notice you had 1 dead hole......

 

Its running really lean now that you have all 8 cyl.If it was tuned on 7 cyl and afr was tuned that way. Add about 11% more fuel for the dead hole and it will be close.FYI you need to redyno tune with widebands to make it right.

 

Personally if you can get a cheap tow to the dyno tune thats what I'd do....I wouldn't run a motor that is that out-of-tune.

 

Damn Justin tough break...did you get the oil pressure thing figured out? If you need some help you can always PM me.

Matt

 

Shouldn't be cherry red lol, that's crazy

 

Problem solved! JmX and I had taken the coil packs off twice and the second time I forgot to plug the wires back in on the passenger side I must've been dumping fuel like crazy into the cats. I'm determined to run on less than 8 cylinders, lol. Thanks for all the advice guys....luckily it was something simple.

 

does it feel better with all 8 plugs firing? get it retuned

 

dear god man.....

glad you got it figured out tho. next time double check everything

 

Since I was tuned with 7 cylinders am I going to be running lean now that I have 8 cylinders and hopefully an additional 60 hp?

 

let us know how much it puts down now after the tune!

 

Better change the oil. You just dumped alot of fuel into the cylinder without spark. Some of it went to the exhaust, but a lot is in the oil.

 

It was making 51 hp/per cylinder, so 60 might not be that far away

 

Justin called me this afternoon. He has everything running good now, and went back and got a re-tune. The car put down 434 rwhp, and 405 rwtq. I'm sure he'll be posting up the graph shortly. Good job Justin.

Matt

 

Here's the followup:

https://ls1tech.com/forums/dynamometer-results-comparisons/230604-g5x3-112-cam-only-dyno-results-434-rwhp-405-ft-lbs.html

I actually just got it dyno'd today. I'll go back for a re-tune next month and lean it out a little more.