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Finally back in a performance car!


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  • 3 months later...

So back in January, I found out that my LS7 suffered from the all too common valve guide wear issue. I had to do something before it dropped a valve and claimed yet another LS7!

 

I decided to have my stock heads redone, since they are so good from the factory. American Heritage Performance did the work, replacing my stock valve guides, springs/retainers, and exhaust valves along with porting and a .020 mill.

 

While I was at it, I decided to swap out the camshaft as well. Put in a Vette-Air Black Panther cam, Katech C5R timing chain, new LS7 lifters, and Texas Speed 7.775" pushrods.

 

And so the work began...

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140315_182320_zpsd26a354d.jpg

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140316_170944_zps77a3ad6b.jpg

 

And the "new" heads:

http://i12.photobucket.com/albums/a204/TRSCobra/20140517_152524_zpsada5319d.jpg

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140517_152537_zpsb26bc3b6.jpg

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140517_152926_zps353f1860.jpg

 

I had a few hiccups here and there, as this is the first head swap and second cam swap I'd ever done. I took my time (2.5 months!) because my work schedule picked up. Nothing like working on it for an hour, only to find you need to order something else to do the job correctly!

 

I got it back together and she runs!

 

Idle video:

http://i12.photobucket.com/albums/a204/TRSCobra/th_20140518_193725_zps567132fc.jpg

 

Already put nearly 300 miles on it, to get rid of the winter gas. She goes on the dyno next week for a tune. I can't wait!

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Yeah, there are quite a few people who are sworn off GM products because of that debacle. I didn't want to mod it just yet, but my head builder said my exhaust guides were 2-4 times the max GM spec. I'll just have to deal with more power now... :(
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So today I took it down to Tom Wong of Wong's Performance Engineering in Vancouver for a tune. Here's the result:

 

http://i12.photobucket.com/albums/a204/TRSCobra/SCN_0001_zps8f8b44d5.jpg

 

508whp/456wtq. Made 510whp on a colder run, but the AFR was way off due to a faulty WBO2 on the dyno.

 

I was hoping for a little more, but keep in mind, this is with the stock intake, filter, and exhaust manifolds! The car drives almost like stock, with just a hint of cam surge if I lug it in 6th gear.

 

Dyno video:

 

http://i12.photobucket.com/albums/a204/TRSCobra/th_GOPR0011_zps1c2806de.jpg

 

The car feels great and runs even better. I'll end up putting some headers and a halltech intake on some day, but for right now, I need to get used to it as is!

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New headers would open that up quite a bit. What size is the cam?

 

Yeah my tuner was saying I'd get another 30-40whp with a halltech intake and a set of long tubes. I'm happy with it for now, and I've exceeded my annual mod budget already. Still need a set of shoes for the drag strip!

 

Cam specs are requested to be kept secret by the manufacturer, but it's got 12 degrees of overlap. (PM sent)

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Thanks for the info

 

550whp with headers and intake is about where I think it should be. So your numbers don't seem too far off. A nice set of pricey heads would get you closer to the 570-580whp range. Also depends on the dyno. There are some dynos out there where your car would only make 470-480whp right now. At the end of the day dyno numbers mean very little. Its all about results at the track(or on the street lol).

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On this dyno, a stock C6Z makes 440-450whp, so a 60-70 whp gain is pretty decent for only 2 big mods. Plus I averaged almost 25mpg in traffic on the 3 hour drive home! :D

 

The stock heads are actually surprisingly good and even better with a porting job, which makes it hard for aftermarket heads to be worth the extra coin. I can't find the flow numbers for these now, but when I was comparing, they were on par if not a bit better than most aftermarket castings.

 

There's a few test and tunes at local tracks this next week, so expect some timeslips in the near future!

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Ported ls7 heads are very good no doubt. Some approaching 390+cfm but there are better flowing heads out there. At some point though the heads will outflow the air the short block can utilize and pull in.
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  • 3 weeks later...

http://i12.photobucket.com/albums/a204/TRSCobra/20140620_183820_zpsfnthg3hs.jpg

 

Not sure what's worse, the stock tires or my ability to drive the car! :lol:

 

That timeslip is from my first pass, clutch master gave out half way down the track on the second one.

 

My ride home:

http://i12.photobucket.com/albums/a204/TRSCobra/20140620_220838_zpsoj3nsq4y.jpg

 

The shitty thing is I could've bought a Tick Performance master cyl for the price of the tow...

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Often getting a good time slip on the first time out is easier said than done, especially with a vehicle that might have traction problems. 11.9 on street tires is not bad, it just could be better. Fix the clutch issue and have at it again.
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  • 2 months later...

Been a hectic few months. After replacing my clutch master cylinder with a Tick performance unit, the clutch pedal was still on the floor, so I looked in the bellhousing vents and found this:

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140807_172240_zps1wvhfqle.jpg

 

Part of the clutch marcel spring in the disc.

 

Here's the disc:

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140822_214535_zpsbtppumdv.jpg

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140822_214450_zpsuugsi6y2.jpg

 

Safe to say it needed replacement, so I had a Mcleod RXT twin with billet flywheel and new GM slave/TOB/pilot bearing put in its place. (google photo)

 

http://kyspeed.com/images/mcleod.jpg

 

At the same time, I threw some new GM C5 axles in, as they are much stronger than the early c6z units.

 

Well, then I needed to do something about the traction issue. So I ordered up some Weld RTS in 18x7 for the front and 17x11 rear.

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140826_180757_zpsleqwijw0.jpg

 

 

For tires, I chose Mickey Thompson ET Street drag radials in 315/35/17 and Bridgestone Potenza S04 Pole Position 225/40/18 for the front.

 

http://i12.photobucket.com/albums/a204/TRSCobra/20140827_180053_zpse6b2pb5w.jpg

 

 

All mounted up!

http://i12.photobucket.com/albums/a204/TRSCobra/20140829_134928_zps3ijfakpj.jpg

http://i12.photobucket.com/albums/a204/TRSCobra/20140829_135242_zpscbdntymh.jpg

 

 

 

No 1/4 mile time slips just yet. I did run at the Northwest Streetcar Challenge yesterday though. She hooked pretty well once I got used to the new clutch and traction!

 

Here's a run against an 860+ whp blown/n2o challenger:

 

Under his hood:

http://i12.photobucket.com/albums/a204/TRSCobra/20140829_180229_zpsgsdmocga.jpg

 

I did better than I thought, but 4500 lbs is a lot of car to move. Had a closer run with a 350-370whp, 1900lb n2o EG civic!

 

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That sucks about the disc, did you swap out yourself? The mickey's I'm sure are making a night and day difference. I have been wanting to install a tick master cylinder and remote bleeder over winter. Not looking forward to dropping TT/trans/diff to do it.
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That sucks about the disc, did you swap out yourself? The mickey's I'm sure are making a night and day difference. I have been wanting to install a tick master cylinder and remote bleeder over winter. Not looking forward to dropping TT/trans/diff to do it.

 

With the exception of the master cylinder, I had a shop do the work this time. (Hence the lack of certain pictures) I've read nightmares about doing the job on jackstands, and I had an upcoming event I already registered for, so I just paid the cash to have a pro install it.

 

Here's a comparison of the stock and tick master:

http://i12.photobucket.com/albums/a204/TRSCobra/Mobile%20Uploads/20140807_112258_zpsscu1ilgu.jpg

 

Pain in the ass to get the car ready to trailer there though.

 

Installed a much needed front tow hook to get it onto the trailer:

http://i12.photobucket.com/albums/a204/TRSCobra/Mobile%20Uploads/20140812_181714_zps0xouwhwe.jpg

 

http://i12.photobucket.com/albums/a204/TRSCobra/Mobile%20Uploads/20140812_182343_zpsdqyshoya.jpg

 

At least the orange part is removable.

 

Lookin' good!

 

1/4 or 1/2 mile runs?

 

There were 1/4 (yellow) and 1600' (American) flags on the course. With a 40 roll, I was hitting above 140 mph at the 1600' mark.

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