Keep losing power???

[acammer]

Originally Posted by Maroon 6.2L SS

Thanks for the responses everybody. I will mention the rocker/springs possibility when I take it in to get it Dyno Tuned. I'm thinking it might be the remote custom tune as well. No disrespect to the tuner whatsoever.

I started off with a little over 109mph and now I'm down to a little over 106mph

That's not awful. These cars can be pretty heat sensitive - I don't know what you're staging lanes practices are, but I would not be the least bit surprised to see a car lose 3mph with a few thousand feet more of DA in the middle of the summer, combined with some heat soak of sitting idling in the lanes in higher ambient temps. Stock tune starts pulling timing at 212*F ECT and/or at 131*F IAT - both of those are pretty easy to hit idling in 80*F of ambient air, especially if you have a stock thermostat and fan tuning. I run a fan switch, cooler thermostat, and am a nazi for open hood engine off at the track unless the car is making a pass, or within 90 seconds of making a pass. My coolant temps are never over 190*F, and my IATs are kept under 100*F - so the car is nice and consistent.

What do you data log and tune with? Anything you can share with this group? If you had a broken rocker you'd have a dead hole and you'd hear it, feel it, and have a check engine light. Usually if you have a broken spring you'd have some friendly valve meet piston action going on, and you'd definitely know it. There are odd instances where a spring can break but not fail completely, and just hurt the top end - but that's pretty rare.

[Chris49066SS]

Heres a tale for you, Andrew. When I brought my car to GPI last week, I had been experiencing a misfire. I thought it was a spark plug, which, when I swapped them out, that was true. That spark plug was toast and drenched in unburnt fuel. I drove it 6 hours to GPI. When they got the valvecover off to start the trunnion upgrade, they found an oem rocker arm had broken right off on the valve side! The rocker, at that point, looked more like a set of fangs that were literally chewing up the valve retainer.

Here's the rocker.



Heres the retainer.



This is a titanium valve retainer. It miraculously held onto the valve under heavy pummeling from the evil, broken rocker. If it failed and its valve were to drop, we knew that catastrophic failure could have ensued. Imagine a valve falling into a cylinder and meeting up with a piston which then punches it straight back up into the combustion chamber..

My shop said that I was unbelievably lucky that the valve didn't drop, and that the odds of this situation happening are slim to none. They said if it hadn't been a titanium retainer it undoubtedly would have failed. To be fair, I have a pretty loud car, making it a bit more difficult to hear abnormalities, but I didn't hear it. I definitely had a lot of power loss though, since I was running on 7 cylinders.

[acammer]

Originally Posted by Chris49066SS

Heres a tale for you, Andrew. When I brought my car to GPI last week, I had been experiencing a misfire. I thought it was a spark plug, which, when I swapped them out, that was true. That spark plug was toast and drenched in unburnt fuel. I drove it 6 hours to GPI. When they got the valvecover off to start the trunnion upgrade, they found an oem rocker arm had broken right off on the valve side! The rocker, at that point, looked more like a set of fangs that were literally chewing up the valve retainer.

Here's the rocker.

Attachment 993726

Heres the retainer.

Attachment 993727

This is a titanium valve retainer. It miraculously held onto the valve under heavy pummeling from the evil, broken rocker. If it failed and its valve were to drop, we knew that catastrophic failure could have ensued. Imagine a valve falling into a cylinder and meeting up with a piston which then punches it straight back up into the combustion chamber..

My shop said that I was unbelievably lucky that the valve didn't drop, and that the odds of this situation happening are slim to none. They said if it hadn't been a titanium retainer it undoubtedly would have failed. To be fair, I have a pretty loud car, making it a bit more difficult to hear abnormalities, but I didn't hear it. I definitely had a lot of power loss though, since I was running on 7 cylinders.

Wow - that's EXTREMELY lucky. That's incredible it held together and didn't cost you a motor. Every time I see something like this posted I wanna go rip the valve covers off and just have a look at things to be sure! I'm really glad you didn't get burned by this - go buy a lotto ticket (and share with your friends )

[Chris49066SS]

Originally Posted by acammer

Wow - that's EXTREMELY lucky. That's incredible it held together and didn't cost you a motor. Every time I see something like this posted I wanna go rip the valve covers off and just have a look at things to be sure! I'm really glad you didn't get burned by this - go buy a lotto ticket (and share with your friends )

Haha yeah that woulda been a disaster. At least it didnt take the needle bearings out along with it, too. It could have been ridiculous.

[Maroon 6.2L SS]

I'm taking the car into a performance shop tomorrow to get the engine thoroughly tested. I will post on here what the results were, if any. Thanks everyone for all the replies.

[Maroon 6.2L SS]

Hey all. I just got the results back from getting my motor tested at the local performance shop. Everything tested out within spec. I was relieved but also surprised and confused. The only thing left that I think would be causing my issues is the emailed custom tune, no disrespect whatsoever to the tuner, it's just my last thought. I will be getting a dyno tune over the next two days. I will let you know what happens when I take it to the strip next (hopefully this Sunday)

[Maroon 6.2L SS]

Hey all, well it looks like my problem has been fixed. After 2 months of replacing stuff/updating stuff etc...getting a dyno tune fixed my issue with the car getting slower. I went from 13.39ET in my last outing 3 weeks ago to 12.99ET in this outing. Same track, roughly same DA and everything else being pretty much the same and consistent with before. It must have been the custom email tune. Not sure why things got worse with the custom email tune. Now I feel like I have to start all over at the track but that's a good thing

[Roader]

Could have been the tune but it could also be track prep with the 60’ time dropping so much. What was mph the last time out?

[acammer]

Originally Posted by Roader

Could have been the tune but it could also be track prep with the 60’ time dropping so much. What was mph the last time out?

Agree - I think we need to see the whole time slip to better understand what exactly was changing. I look and MPH pickup from 1/8th to 1/4 as a good indicator of hp, if it 60' about the same but did substantially better in the MPH department I'm inclined to agree it was the tuning.