Not making power any more...

JeffP-Z

I am hoping to get a little help debugging this new issue. So I am not sure if I said this in my previous posts, but I had a little accidental 'money shift' the other week racing. It completely shredded the clutch plate. I have since replaced the clutch with the JWT 1200 lb clutch kit and the 14 lb fly wheel. Also while it was apart, my new Berk resonated test pipes arrived and I installed those. After getting the clutch installed and the car back together this morning, it is no longer making much power. It seems like it wants to idle around 800 rpm now and the almost falls on its face at lower rpm. I had been told by several people that the test pipes should not affect the tune that much (which I was skeptical about) but at this point since I had that money shift, just replaced the clutch, and added test pipes I wanted to ask before just turning wrenches all day. If the release of all that back pressure by changing the cats to test pipes is the cause based on feedback from you guys then cool, but I am concerned that there may have been more damage than just the clutch from that incident. Please let me know your thoughts on this before I just start testing random things like changing back to cats to test, pulling plugs and doing compression tests, etc...

Thanks and Happy 4th everyone!

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- Jeff
Drift Z: 2010 370z, TopGun Rotrex Supercharger, ID 1300cc Injectors, FI Long Tube Headers, GReddy RS-Race Single Exit, Setrab PS & Oil Cooler, BC Racing BR Coilovers, CJM S1.SE Fuel System, Walbro 525 pump with the CJM Billet Fuel Hat, OS Giken Superlock 1.5

jchammond

Unsure if you’re throwing any codes; but I know using impact wrenches on exhaust could damage O2 sensors, also if you have an exhaust leak in that area...would cause issues.

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JeffP-Z

In theory, wouldn't test pipes feel like an exhaust leak to a system tuned on 93 with cats having them now removed?

No codes, no impact tools, I am always super careful with o2 sensors at $200+ each. I used only a crescent wrench to tighten them after hand threading them.

__________________
- Jeff
Drift Z: 2010 370z, TopGun Rotrex Supercharger, ID 1300cc Injectors, FI Long Tube Headers, GReddy RS-Race Single Exit, Setrab PS & Oil Cooler, BC Racing BR Coilovers, CJM S1.SE Fuel System, Walbro 525 pump with the CJM Billet Fuel Hat, OS Giken Superlock 1.5

SonicVQ

Sorry to hear about this... It can happen so easily.

Since the engine was revved much higher than redline, you might want to do a compression test and check the oil pressure to rule out any mechanical damage.

If a valve floated, it might have smacked a piston and bent a valve or put a small hole in the piston.
The oil pumps also don't like RPM greater than ~8,000 and since your clutch exploded, you were probably around 10-13,000 RPM or more.
You are lucky your oil pump didn't shatter!

NissanZ34

I would guess you also damaged the internal components of the engine. As suggested by SonicVQ, go ahead and perform a compression test. My bet is the piston rings are shot at a minimum, maybe there could be damage on one of the pistons too. Make sure to replace any parts that look worn while the engine is appart.

JeffP-Z

Thanks for the ideas. I was planning on doing a compression test but I had been just out of sorts for the past 24-48 hours....but I can safely say, not a compression problem. Cold compression test came out 243, 240, 240, 240, 245, 241. Although my spark plugs were just slightly tight in there and that peaked my curiosity a bit as if the pressure backed them off some or they vibrated loose as if 1/2 turn past snug was not enough after I changed them about 2 weeks ago.

As far as oil pressure/temps go, I do not have an oil pressure tester and it appears they stopped with oil pressure from the switch to 370 from 350...but I have driven the car some prior to the compression test today and in 95+ degree heat in Texas and me pushing the car as hard as I could to test it after my clutch rebuild, it is not getting hot, staying between 185 and 200 max.

Any more thoughts before I just drop it at HoustonZ and pay to have them diganose/fix it?

P.S. Since posting originally and driving some, it seems to be producing decent power, just sluggish in comparison to what it was pre incident and changes in repair. like I said it wants to idle around 800-900ish now and from a start I have to rev it to about 1500-2000 to keep it from bogging and then it will actually spin the tire(s) [open diff still lol] some and it will chirp the tires in second, which is of course way less than pre-incident.

__________________
- Jeff
Drift Z: 2010 370z, TopGun Rotrex Supercharger, ID 1300cc Injectors, FI Long Tube Headers, GReddy RS-Race Single Exit, Setrab PS & Oil Cooler, BC Racing BR Coilovers, CJM S1.SE Fuel System, Walbro 525 pump with the CJM Billet Fuel Hat, OS Giken Superlock 1.5

JeffP-Z

Update: The cause of the power loss has been discovered. When I replaced the clutch my absent minded a$$ forgot to index the flywheel. It was off by 3 bolts. While it should have normally thrown codes, it wasn't.. We noticed when we looked at it through the tuning suite that the cam sensors were taking a long time to return to 0. so we began to suspect that even without codes and dropped the tranny to confirm it. Problem solved!

__________________
- Jeff
Drift Z: 2010 370z, TopGun Rotrex Supercharger, ID 1300cc Injectors, FI Long Tube Headers, GReddy RS-Race Single Exit, Setrab PS & Oil Cooler, BC Racing BR Coilovers, CJM S1.SE Fuel System, Walbro 525 pump with the CJM Billet Fuel Hat, OS Giken Superlock 1.5