ok, this is a really long story turned short for interest of time.

I have a built Y7 block with Y8 head. Already dynoed and ran it at the track and it ran perfect. I forget exactly what I changed, but just one day the car has nothing above 6000 RPM, so I took out the zex cam and threw the stock Y8 back in. Still no power above 6K. It feels like it misses a little bit. It is more evident at 10 psi then 15psi. I also gave the car lots of timing, then took lots away, to no avail. I adjusted cam gear settings. I have redone my timing belt about 5 times. Change distributor, plug wires, map sensor and timing maps. I can't figure out what the hell is going on with this thing.

With the Y8 cam and the Z6 cam gera, I advanced it to 4.5 degrees when I put both cams in. It ran fine, untill one day, this all started happening, after I redid my intercooler piping and fixed my wastegate. Any ideas would be helpful.

Also compression check yields 150 on all cylinders. WOT, engine hot.

 

Are you the same dude with the hybrid 16g setup?

 

Yep. Was looking to get the damn thing dynoed again with everything fixed on 20 PSI. So it needs fixed by wednesday!

 

wow gl gettin it fixed john, id check ignition components...

 

ditto....... throw a new dizzy on and see what happens (known good dizzy if you have access to a buddies or something. )

 

also i know you know your **** john, but hows your plugs looking? have you datalogged anything?

 

I already put in a new dizzy, map sensor, plugs and wires. So that is covered. I am a dumbass, it is kinda hard to watch the boost gauge and the road and the wideband and RPMs, but I know my problem now. I go to 10, my low boost, and the bastard drops right off to 5. The only thing I changed was an HKS bov, instead of my DSM. I am going to throw the DSM back on and redo ALL of my vacuum lines.

 

Can any one offer some advice. I re did my timing belt today, timed the motor, changed dizzies again, wires, plugs, and tuned it. The car feels like it might be lossing fuel in one cylinder. So I am going to change the fuel filter tomorrrow, and then pop in a new set of injectors. That is all I can think of. The wideband still says it is rich, but honestly timing has been covered completely, it isn't timing related, as I first thought.

 

replaced fuel filter and FPR, still no change. after 6K still falls on its face.

 

Is that a vtec head? Those symptoms sound exactly like a vtec not kicking in. The motor is tuned for the vtec profile and becomes fat and lazy with no vtec. On the dyno a 600whp motor will become a 300whp motor. When this happens, it will not show up fat on an a/f guage either.

 

yeah is vtec engaging?

 

I can atleast say that I have a vtec light hooked up, single cam kinda needs that, and you can hear it engaging. I thought that as well. When I had the cam out, and the rocker assembly apart. Some of the lost motion assembly pieces fell down. I put them back in, and figured it was ok.

 

ok, with vtec on it stutters like crazy at 6K, I don't think it is dropping out of vtec. But with vtec turns off, it revs relatively smooth through the RPM range, but with no power.

 

Hmm... you sure your cam timing is right? I can't think of anything else.

 

Yea, to my knowledge, I have done it about 5 times, because that is what I thought it was. But even doing it different ways, yields no difference. Even adjusting the cam gear.

 

Well my lost motion assemblies seem to be rather tight. I am not sure if that is the cause of my loss of power though. They all fell out at one time, and running them when they weren't in properly could have caused something to warp or something? I am just running out of ideas here.

 

The problem was the lost motion assembly. I took off the rcocker arms and messed with them a little bit. And all is good now. No more power loss up top. The mid rocker arms are a little tight, but all is good now. Thanks for the help!