RPM Drop at WOT Hot?

[lakercr]

Probably, I'll take a look. If not, I'll make some for you this weekend.

 

[kviper]

Interesting! I have a manual boost controller and a gems type fuel controller running a aftermarket muffler and a small amount of added boost. AFR is on the rich side and doesn't seem to respond much from taking some fuel away. I have no extra fuel added at causing speed and it's in the upper 12's. Bad plugs= poor burn would show richer AFR's?

 

[lakercr]

Yeah, you'd think. The sleds will start, idle, and run fine at cruising speeds: the sled feels completely normal. Out on the lake they will be down a few hundred rpm and you'll think it is a clutching issue (and sometimes it is) but you'll be surprised how much the sled wakes up with fresh plugs.

Don't read too much into my a/f numbers above. I'm chasing an issue on the fuel delivery/a/f sensor side right now.

 

[kviper]

Were loosing our snow now so not sure I'll know till next year on the plugs but I've chased clutching, did the clamps to eliminate any potential boost leaks, did boost leak test with about 2psi drop frome 14 over 30 to 45sec (drop seems to be coming through the bypas/bov). So it would be nice if it was just the plugs!

 

[KnappAttack]

I've seen it be plugs before also, but it didn't dawn on me until lakercr and I were talking about it over email earlier the last couple of weeks. Sometimes I do too many things at once now and again, but you have no choice when winter is getting so short. I swapped out plugs and map sensor all at once earlier this winter, but I was having boost spiking up and down as well and trying to cure that. Either way now I can pull RPM along with big weight in the primary and my boost spikes are super smooth now too.

 

[fatchance]

Mike the sensor you swapped out was it the 2 piece? Just curious. That was a bogus design if you ask me.

 

[KnappAttack]

Mike the sensor you swapped out was it the 2 piece? Just curious. That was a bogus design if you ask me.

It sure was. Alum on the bottom with the o-ring.

 

[fatchance]

yup, Junk. Anybody that has one wants to seal that thing with RTV sealant

 

[STAIN]

Back to the plugs---are you saying the plugs are " blowing out" or are just worn and not providing adequate spark for the larger tunes?
I have felt plugs blowing out on a 1100 turbo, but it felt like a skip. We also had to shorten the gap on the plugs to solve the problem
I will be trying some new plugs this weekend also.

 

[lakercr]

No, not blowing out. The plugs I just pulled look perfect, and we’re gapped when I put them in last year. I haven’t done my ROV bypass yet, so not sure if it’s related to the oil mist goo becoming part of the combustion process, the octane boost I run, or neither.

what I do know is that for $15 and 10 minutes of your time, it’s an easy one to cross off the list of possible issues if you’re chasing rpm.

 

[yamahahaapex]

just changed my plugs. Wasnt chasing RPM, chasing boost and although conditions were better the result still hasnt improved but I get to cross it off the list!

 

[DooZ]

No, not blowing out. The plugs I just pulled look perfect, and we’re gapped when I put them in last year. I haven’t done my ROV bypass yet, so not sure if it’s related to the oil mist goo becoming part of the combustion process, the octane boost I run, or neither.

what I do know is that for $15 and 10 minutes of your time, it’s an easy one to cross off the list of possible issues if you’re chasing rpm.

What did you gap them to?

 

[lakercr]

.020"

 

[Crossfire12]

It’s IATs that bring RPM s down, it’s a motor trait, your good when it’s cold then warm your pms come down, doing 100mph for miles what’s the IATs then.

 

[Turboflash]

I have had times when rpm's have been down 500 rpm's and my intake temp is 60f.

What is the reason they changed the fuel line return fitting for 2018?

Fuel return fitting changed in 2018. Different part number. Replacement and the one used on all models after 2017 is black. 2017 was red. There's an orifice in that fitting. The orifice size was increased in 2018 and beyond. The reason was under some situations, the orifice was too small and wouldn't allow enough return thereby causing fuel pressure to increase and richening the AF mixture. The new fitting has a larger orifice size.
Wonder if that's what's going on with this situation? Fuel pressure too high?