Did a cam swap. After cam swap car was cutting up around 6K, on HP tuners, im not getting any Knock but im losing 2 mph when it starts happening. I took off my Cats ( which were off before cam but put on during cam ) that didnt fix it, i changed the plugs, that didnt fix it. thought it was my clutch slippin and i needed a clutch anyways so i did a clutch and new flywheel ( ram ) that didnt fix it, checked for leaks or unmetered air at the manifold ( 90mm ) that wasnt it..is it valve float?? feels like im hitting the rev limiter but im no where near it ( 6800 ) Thanks. Im running 918's and my intake lift is .599, im pretty close to the limit although a lot of you tech heads say the 918's are good for that.

Scoobs

 

I think you may be right Scoob. It didnt feel like anything I thought, could very well be float. About the right rpm also.

FWIW the 918s Scoob is using are slightly used, but didnt have a lot of miles on them, they were my old ones used with a TSP 231/237 .598/.595 112* cam, never had this issue and I pushed them beyond 6000rpms.

Charlie

 

It almost feels like its running out of fuel or spark, really weird

 

Yeah, it does really, but it is not the rev limiter thats for sure. Log showed only 6200 rpms at my runs max and it was "issuing" at that rpm. Maybe time for a Walbro In-Tank, of course a FP Gauge will tell the tale. I am thinking not fuel, will look at the log for fuel traces again, should show in the O2's and IPW.

 

well, im going to go to Rons, buy new wires, try that, if not that, then ill install the 30lb injectors...need to tune for them.

 

Wow, look at all the responses, come on guys, had i said " What is the best Cam" im sure i would have gotten some hits lol

 

If it was fuel related it would go lean and get KR. It has to be either in the tuning or vavle float. Vavle float is very hard to "Feel", but can cost you 20 or up top. The 918's should hold that kinda pressure though, lord a few guys around here are killing the 918's I installed for them! lol If it was a bad wire it would show misfires on that cyclinder. Holla at a brotha scoobs! I'm home today.

John

 

John, thats the weird thing. I looked at the IPW vs O2's for a leaning, as I have seen cars go lean without a SES or KR. They looked normal. Looked at KR, nothing reported, and this bastard has a Y pipe smacking the car hard enough I about mustanged myself when I launched soft out of the hole. I was like WTF, then realized it was the exhaust. When my Xpipe touched, not even banged, it set the SES. Fueling seems to hold although his IPW vs. RPM suggests he is well over 80% IDC. Spark, well, I've heard issues with Taylor wires having air trapped in b/w the boot and plug and blowing them off, but these are not like that. Seal is good, idle and PT smooth as silk, all the way to about 6,000rpm and its similar to hiting a rev limiter. So I checked that and no way thats happening, besides the IPW/O2's would have seen it. I am wondering, after not sleeping last night looking over the few logs I have from his car, if the KR sensors are out of touch with reality.

 

What kind of rockers are you using? If stock, It might be worth it to look elsewhere. In your sig it looks like T&D's or Jesels, if that's your motor. I know for a fact that those rockers require VERY stout springs to keep them moving at high rpm.

 

He's running stock rockers.

 

Charlie,
Disable the knock sensors and see if that is it. Maybe the intake pinched a knock sensor wire in the back when putting the LSX on the car. If it stops doing with the sensors disabled then we can go from there.

John

 

John, I guess that would make sense in the troubleshooting scheme of things. I put the low octane as high minus 4* but with the KR not reporting, how would it effect anything?

 

I have a customer with a 5.3 truck with a powerdyne on it. When his knock sensors started giving him trouble the truck would fall on it's ***. Just a thought.

 

Good info, thanks John, just woke up, going to test the wires now. We'll get to the bottom of this soon.

 

The Wires didnt fix it doing the injectors now, if thats not it, new valve springs and a big WTF if that fixes it.

 

Thank you for the help Drew778, the 30lb injectors are on, no go. Looks like the "CheaTR" cam may be too big for the 918's, we'll see soon. Ordering springs tonight so it may be a week before we know.

 

Did you measure the springs since they were used?
I ran 918's with a .608 lift with no issues to 6800 rpm.
Those could be tired.

 

Scott, you NEED me to adjust the Injector table for these injectors before you drive around too much. Thats a big fueling difference you made. The 30# will be flowing lots of fuel, the PCM thinks it still has 28.8# in it. I will be at the track tonight and can do it there. I cant see it being the springs, but at this point, I am wondering maybe it is.
Odd how that Y pipe smacks the **** out of the flooring, but there is Zero KR. Hell I get a slight tap and my KS' see it. I want to look into the KS issue first, but if its springs, then will get it taken care of with you.

 

Charlie, i got a set of the PRC Platinums on the way, good price too, thanks TSP. Consider them insurance for a big stick i may do in the future. The car is parked on jack stands awaiting a weeks worth of detailing before the show the following weekend. I wont be at the track this weekend because im on nightshifts Fri-Sun. Ill be around Mon and Tue night. I wont drive it until you get a chance to come over. Springs will be here Wednesday.
Scoobs

 

Might as well put a donkey dick cam in it while you got it down!