Kylekay

2 years ago I had MTI install their Stage II heads, T1 cam, Mac headers, 160* tstat and programming that was included with the package at about 5,000 miles. I got 405 rwhp.
1 year later I had the car dyno’ed again, same place, I had about 28,000 miles on her than and tested at 386 rwhp a loss of 19HP.
1 month ago at about 45,000 miles I had a lifter break and had to replace the cam. I went with their C2 cam and also got the LS6 intake installed along with better lifters and new springs to handle the higher lift. The car tested at 389 rwhp. WTF??? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> Where did my HP go?
From similar setups I have seen on this forum I was expecting around 420-440 rwhp. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
The only reason Jeff and Jason at MTI suggested is that the rings could be causing the loss of power. This car has never been to the track and rarely raced on the street. No other power adders have been used and she burns less than ½ quart per 3,000 miles. I am planning to get a compression and leak down test soon to see if I do have a ring problem but I doubt it. I changed the spark plugs and they looked good.
Has anyone seen this kind of power loss before? Is it normal to lose this much HP after 40,000 miles? Any ideas?
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
The car is a 2000 NBM Firehawk M6

Kylekay

I think I run lean, I don't have Atap so I'm not sure but I have problems with pinging and it gets worse the hotter the engine gets, ofcoures.

383ss

iTrader: (14)

may sound stupid, but have you ever replaced your fuel filter??

Kylekay

I wish it would be something that simple, but yes I replaced it a few months ago and I have run 44K through her.
BTW, there is no such a thing as a stupid question.
I want to figure this out and I need all the help I can get.
So thanks and keep the ideas coming! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

SSINFUL

Yeah, I gotta dumb question: Why do those mods and then "never been to the track and rarely raced on the street"?

Kinda like having DirecTV & then only watching the local channels...

Kylekay

1. I do not race off the line, I can not afford a new rearend or clutch. This car is my daily driver and right now I do not have another car to use.
2. I love a very strong car <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Now if you have something that can actually help I'm ready to hear it.

I8COBRA

iTrader: (56)

After doing heads and cam on my old LT1 I ruined the rings by constantly running rich and lost 30-40 hp.

MY99TAWS6

iTrader: (3)

Dynos are that consistent I don't think...was your car hotter when you ran the last test..like heat soaked from driving it there...did you have any knock retard during the run.What was the wideband o2 readings for air fuel.Maybe you need your injectors cleaned..how is your fuel pump ..maybe check pressure..I think also your injectors may be too small..I have done calculations and most people seem to be running them way past 80 % recommended and think this might be cause some horsepower reduction or limiting..is your car standard..clutch slippage???
and what about your 02 sensors..time for new ones mabye..clogged cats.??

Kylekay

Good questions MY99TAWS6,
Can cats go bad in 40,000 miles? The cats were installed with the headers. The guys at MTI said my injectors are fine but I have my doubts to, they also said the clutch and fuel pump are OK. Will injectors that are working past 80% slowly decrease their output? MTI did replace the front O2 sensors but did not tell me what the A/F or KR was.
Thanks