I had the car dynoed back in the summer and have the graph below. This was right after the cam and valvetrain swap. My tuner said he thinks the breaking up at the end of the graph is due to my injectors being maxed out. I know they are near are at 100% duty cycle but everyone else claims I have valve float. Im puzzled because I only had the car up to 5900rpm on the dyno and it showed that but I spin my car up to @6500rpm now and it pulls all the way there and traps over 110 mph in the quarter through an automatic. The power is definetly there and it runs strong so could it still be valve float? I thought the car would feel like it has no power if you have valve float? Valvesprings are Crane 10308-1 with a .600 lift and spring rate of 408 lbs./in.

 

probably not valve float or the lines would be alot more squiggly and HP would not be rising like it is there. If set up at 1.870 or lower, you have PLENTY of pressure for the CC 503 cam and will not be floating the valves due to spring pressure.

If they are set up taller than that (should not be with stock length valves) the pressure can be too lowand maybe a problem.

Rockers too tight can cause problems like that. Adjust them to 1/8 past zero lash and that is it.

Coil, opti, plug wires, spark plug, fuel pump, injector maxed out, etc can all do that.

If you have 1.6 NSA rockers and guide plates, make sure the pushrods are not bottoming out on the back of the guide plate (closest to stud). This does some weird stuff to valve tranes and puts alot of stress on everything in the valve trane.

Also make sure the injectors are connected to the correct plug/wires for that cylinder. I have seen people have hell for that reason also.

Lloyd

 

Thanks alot for your help, looks like Im gonna pull of the valve covers and check out my rockers and go from there. I checked that the injectors are connected to the correct plug/wires before and I have a new opti, plugs, and wires so Im still thinking the injectors if the rockers aren't too tight.

 

Maybe its because you have longtubes...shoulda went with the Mac mids and you would have been good to go like me!

 

hahaha yeaaaaaaaa

 

What was the a/f and timing? Where there any black puffs of smoke coming out of the exhaust during the run?

 

I find it odd that you think your injectors are maxed just because someone told you that, when you haven't scanned the car to check.

If your injectors are working properly they should not be maxed at that power level. If you suspect injectors just have them checked out/cleaned etc. I doubt you need to upgrade them.

 

im still running stock injectors. although the duty cycle is on the high side, they are throwing enough fuel at the motor all the way to 6800

 

I agree, injectors should not be maxed out with CC 503 and stock heads or anything making that HP # for that matter. Just throwing things out there to check.

If it was valve float, once it starts, it just gets worse in a hurry and the RWHP #'s will not hang on for another 500 RPM with HP #'s rising. The HP #'s fall like a rock with in a few hundred RPM as well.

The dyno #'s can be a lil lower than what you were thinking due to the 3600 stall in your sig.

Good luck with getting it ironed out.

Lloyd

 

A/F was 12.8 and no black smoke was coming out. I dont recall the timing but it is boosted over stock. The car was dynoed with the stock stall but numbers turned out better than I was hoping for really Im not a big dyno # fan Im all about track times and it definetly performs on the track. I just have no idea what the problem could be and Im starting to think maybe its not really a problem at all? I had a code at the time and still do for an 02 sensor heater circuit if that has anything to do with it?