verbs

We can't figure out what the heck could be wrong. I'm making way less power than I did with a much smaller TR230/224 cam, LS6 intake, stock waterpump, and stock YT rockers.

I've recently added the G5X3 cam, Meziere EWP, and port matched LSX intake.

My dyno graph shows something is definately wrong. The graph looks like a seismegraph, not a dyno graph....and this is after maximum smoothing!! I stop gaining torque at 3800rpms....it stays flat all the way until 6200rpms. I should keep gaining torque easy up to 4800+rpms.

My car should be making way more horsepower than it is. Louis of LG thinks it could be a bad MAF sensor based on the symptoms I've described. My A/F is perfect, no knock retard or detonation, plugs look perfect, and no stumbling except the car has a tougher time idling with the G5X3 vs. the TR230. Ignore the A/F spike at 6000+rpms, that was the o2 sniffer falling out of the exhaust.

I did just have 7 bent valves replaced and my heads milled because they were slightly warped. The heads were fully tested and are said to be in great shape.

66ImpalaLT1

I cannot view your graph.

verbs

I can't resize it...but there you go

Todd@AZPowerAndSound

iTrader: (1)

sheesh..whats goin on verbs????

Todd@AZPowerAndSound

iTrader: (1)

a/f looks good. graph looks like ***. Hows it feel on the street though? Did you take off those 5.3s or no?

theres definitly no reason for it to idle so bad...Mikes is fine. You have a different lsa?

verbs

I wish I knew

Same heads, just fixed the bent valves. It felt slow on the street...about the same as my car did with the old cam and 7 bent valves and a bent head gasket.

It drives fine other than the fact that it hunts for idle a lot more than it used to, its just way down on power.

Don't forget I have an aluminum flywheel which sucks for making big cams idle, and this is on a 112 LSA not the 114LSA you're used to.

66ImpalaLT1

I resized it, feel free to use this link:

http://www.zerohp.com/~eclark/Bad%20...no%20graph.jpg

Todd@AZPowerAndSound

iTrader: (1)

dammit check your mail

66ImpalaLT1

Anyway, did you log your dyno pulls with Autotap or EFIlive?

Jason99T/A

iTrader: (21)

Does the car make a clean pull on the dyno (sound normal,etc.)?

The 6400+ range is definitely your valvetrain. I have yet to have any good results with the Yella Terras for setups trying to turn any kind of RPM past 6500.

Todd@AZPowerAndSound

iTrader: (1)

I think his YTs are gone

AZ Power & Sound

iTrader: (2)

im gonna go with installation error...

verbs

Shop had a multi thousand dollar scanner they were using. I wasn't there for the dyno but they said everything looked OK, and they went and rechecked to make sure everything was plugged in.

verbs

I wasn't there to hear it, but like I said above, no audible knock, stumbling, etc. They said everything sounded fine.

Todd@AZPowerAndSound

iTrader: (1)

eww screw that...no beat downs on the dyno without me present.

66ImpalaLT1

I'd be interested to see the MAF GM/sec and Frequency from one of your pulls. Can you get them to export a log file and email it to you?

verbs

I can call em tomorrow, but I doubt they logged it. I'll have to Autotap it myself and save that log. I'm going to test the MAF Frequency and gm/sec.

Jason99T/A

iTrader: (21)

I would check the obvious first (bad sensors,etc.) If those check out good, I would look REAL close at your valvetrain.

verbs

I don't know how those Comp R lifters affected anything. I have a preload between .004" and .018" depending on the cylinder. We couldn't get it exact using the non-adjustable YT rockers and some shims. They did the preload measurements with the engine cold, but I heard someone mention that the engine should be warm when the preload is measured. I'm not sure if this is a problem.

Also, I have 7.35 pushrods on the exhaust, with 7.4 pushrods on the intake. This was done because my intake and exhaust preloads were off by about .020" and since the YT rockers are connected, I couldn't shim the exhaust side more than the intake or else I'd have cockeyed rockers. Maybe the different length pushrods or lifter preload are places to look at.

Trojan T/A

iTrader: (1)

Do you think it might have to do with your problems with the LSX intake or maybe the port job? Switching the intakes again would answer that question. It could also be like SSOnYourSix said- an installation problem with the cam being degreed wrong. Or it could be that the bent valves maybe messed something else up. I hope you get it figured out and its a cheap and easy fix.