Originally Posted by '06 Quicksilver Z06 (Post 1585673119)

Maybe I just might take your advice and do a wiggle test at 10K miles…..

Maybe I'll get myself some of those PSI 1511 beehive springs too while I'm at it.

Originally Posted by American Heritage (Post 1585675409)

[...] The stock OEM LS7 PM guides are 7.10MM (roughly) [...]

Originally Posted by Mark200X (Post 1585674806)

I don't think anyone was talking about severe valve bounce... best to not embellish the conversation.

As to your dip, which could be masked to some extent by the cropped smoothing setting on your graph (most seem to use 5, the maximum)...

Originally Posted by MTIRC6Z (Post 1585675503)

There are 'issues' beyond introducing another variable with using roller tip rockers. Even notwithstanding the stupid cost of the high quality shaft systems like Crower, T&D and Jesel (easily $2000 plus $400 to machine off the stock pedestals) you will NEED to insure the geometry of the new system gets set-up properly or you will end up under or over arcing. Do NOT assume the geometry will be correct just by simply bolting on the new system. He's a sure way to ensure things will get set-up correctly...when you ask your 'expert' about setting up the geometry, IF he doesn't ask you how much cam lift you've got, run away very quickly!

Without going into detail I can pretty well guarantee you that the bolt-on full roller systems for the LS7 effectively result in one step forward and two steps backward.

If the price of running bronze guides is getting roller tipped rockers you better have a very thick wallet, otherwise just go with PM thus saving money and the potential of additional issues.

Cheers, Paul.

Originally Posted by American Heritage (Post 1585675409)

For what its worth using the stock PM guides is not really an option. The stock OEM LS7 PM guides are 7.10MM (roughly) and would need and are CNC'd with a step process. The proprietary aftermarket PM guides that we use are just a hair under size and only require reaming to the perfect clearance.

I am unsure if the LS7 OEM PM guides are the exact same guides that were used in previous LS motors.

Very well. We have been using the proprietary aftermarket PM guides for 3 years in both street and some serious all out race application. Some of our heads are going on 35,000+ miles with no warranty's.

Originally Posted by Mark200X (Post 1585674806)

I don't think anyone was talking about severe valve bounce... best to not embellish the conversation.

As to your dip, which could be masked to some extent by the cropped smoothing setting on your graph (most seem to use 5, the maximum)...

Originally Posted by FNBADAZ06 (Post 1579326846)

OK folks.......seems like a lot of activity on threads lately regarding CAI's and associated dyno numbers. I recently had my car re-dynoed in AZ to get a valid baseline before starting the mod quest. Seeing how there's been a lot of questions regarding these products, I decided I'd post up what I recently did and the results of my dyno test. I also had the benefit of having a wideband O2 hooked up to the dyno, and HP Tuners running to data log what the car was seeing.

The car......a 2006 C6 Z06 with 60K original miles, original clutch, an OEM 2010 ZR1 x-pipe and muffler assembly, and the new Halltech MF103 with beehive assembly. I have also performed the shroud prop mod in lieu of cutting my shroud or running a vette-air type ram-air type product. The car was equiped with OEM sized 325/30/19 rear tires on factory wheels during the dyno process. The car is still running the OEM tune as well. No other driveline mods are on this car.

I had an initial baseline dyno done late summer of 2010 during an open dyno day at a friends shop here in Tempe (Phoenix). The car had no benefit of a cool down period, but I didn't have any data logging s/w or the wideband O2 in place to monitor the car, so all I have are the local environmental conditions to show. With the OEM airbridge in place with the ZR1 exhaust, hood open, the car put down a best of 454 RWHP / 434 RWTQ....temp's 86*, 28.92 in Hg, 34% humidity, SAE correction 1.04.
No doubt the car was pulling timing based on IAT's and was probably in excess of 210*+ ECT's, but that's just an educated guess. I suspect that if I had equal environmentals to what I ran in this past week, along with sub 80* IAT's and sub 210* ECT's, I may have been able to register and additional 5-10 RWHP...but that's just a guess.

http://i713.photobucket.com/albums/w...ynocompare.jpg

OK, let's fast forward to last week. I decided to run the car again on the same dyno when I had some decent air to run in, and with the benefit of the MF103. I also wanted to verify my SOTP feeling that a 50/50 mix of pump gas with a specific variety of "race fuel" would help reduce KR while also possibly giving me a few extra ponies....all while still running the OEM tune.

The next 3 dyno runs I'm posting were run back to back to back.....no cool down periods, on straight Shell branded 91 pump gas, and with the hood closed .

dyno run #1 at 3:42 p.m...... 74.51* F, 28.93 in Hg, 27 % humidity, SAE correction 1.02.

…..http://i1217.photobucket.com/albums/.../Dyno2scan.jpg

474 RWHP / 445 RWTQ

..Note IAT's at 79*, ECT's at 192*, 1.1 KR , 24* total timing.

Dyno run #2 at 3:43:52......75.06* F, 28.94 in Hg, 25% humidity, SAE correction 1.02.

476.6 RWHP / 447.8 RWTQ

...Dyno run #3 at 3:45:10 ........76.43* F, 28.94 in Hg, 24% humidity, SAE correction 1.02

452 RWHP / 426 RWTQ

...Note IAT's at 88*, ECT's at 216*, 1.3* KR, and 17.5* total timing !!!
The combination of IAT timing being pulled (above 86*), ECT timing pull (above 214*), and 1.3* KR, conspired to kill 24 RWHP and 21 RWTQ in a matter of 4 minutes runtime on the dyno !!!!! :ack:

Chew on that data for a few minutes :eek:

Also note the AFR's....no real significant changes over the 3 runs.

My next three runs I'm posting is with a 1 hour cool down period, but with a 50/50 mix of pump gas with a specific variety of "race gas", to see if I can elimintate any KR, and maybe eek out a few extra ponies from my stock tune.

Originally Posted by ctsv510 (Post 1585131036)

I just picked up my first corvette about a month and a half ago - a 2006 2LZ Lemans Blue Z06, bone stock with 15k miles. I came from a 2005 CTS-V that I supercharged and modded to hell that made 450 rwhp and I ran a best of 12.4 @117 mph (2.0 60') at Maple Grove last year before I sold it in April. I know the time sucks but you try and launch one of those cars without breaking something :willy:
...
I liked that car but there is no comparison to the Z! I would have owned a corvette sooner but I needed a backseat. I've been wanting one of these cars since I was about 10, and 20 years later I finally have one. Needless to say, I love this car and I hate these tires (stock goodyears). I'll be replacing them in the spring with some PSS probably.

First mods were 18% tint all around, and satin black centennial cup wheels:...

The plan now is to install ARH 1 7/8" headers and cats and get it tuned. The headers will show up today and they will be installed within the next couple of weeks. The work will be done at CC Performance at County Corvette in West Chester, PA. Quite an amazing shop that does top quality work and employs one of the best tuners around.

I had them put the car on the dyno this morning to get a baseline before mods, mostly just for my amusement.

http://i305.photobucket.com/albums/n...-9-13small.jpg

Looks pretty healthy to me! I'll probably just drive it for a while as is after the headers are on and ponder what move I want to make on the heads.

:cheers:

Originally Posted by gmkillr (Post 1584229818)

Picked up a Z06 and I drove it straight to the dyno. Here are my numbers and a quick pic of the car.

Video...just click
http://s127.photobucket.com/user/gmk...0b437.mp4.html

http://i127.photobucket.com/albums/p...ps4ecb0f0a.jpg

http://img.photobucket.com/albums/v3...sd7aa4290.jpeg

I already ordered some Black cup wheels with yellow lip and im getting ready to order some Nitto NT05 275-30-18 fronts and 345-30-19 NT05R rear drag radials.

Working on a Fast 102 and Nick Williams 102 tb also. Car currently has a Vararam CAI.

Originally Posted by MTIRC6Z (Post 1585675532)

Great ideas there...now just add some stock exhaust valves with PM guides and you REALLY have a 'fix' :thumbs:

Cheers, Paul.

Originally Posted by MTIRC6Z (Post 1585675544)

OPPS!!! Don't you just hate it when the graph hasn't been 'smoothed' enough :ack:

Cheers, Paul.

Originally Posted by Hib Halverson (Post 1585675452)

Trust me. This "dip" couldn't be "masked" by smoothing. It looks much different than, say, detonation or other "raggedness" once sees with no or low smothing. Also, sometimes you can actually hear it on the dyno and, of course, sometimes you know it when the valvetrain breaks.

As for "valve bounce" we need to be careful about use of that term because, any valve bounces on closing. It's the degree of bouncing that is important.

Originally Posted by propain (Post 1585675600)

Oh I agree. That is why PM is a better option. But in cases where people really want to switch to bronze I wouldn't do it without running roller rockers.

Originally Posted by MTIRC6Z (Post 1585675745)

Agreed, and I knew you knew all that, I just felt I had to say it for the sake of some others since you were saving keystrokes :thumbs:

Cheers, Paul.

Originally Posted by propain (Post 1585675837)

Here is my stock chart: [...]

Originally Posted by Unreal (Post 1585676209)

My chart with them heavy ass SS valves and dual springs. Belt starts slipping at 6k and pulled 3 degrees of KR at 6200 which is why power dumped. Didn't get a second pull because pipe blew off. Bumpy charts are not indicative of valve bounce. I doubt you would see it on a dynojet.

https://lh4.googleusercontent.com/-U...206_194802.jpg

Originally Posted by Unreal (Post 1585676209)

My chart with them heavy ass SS valves and dual springs. Belt starts slipping at 6k and pulled 3 degrees of KR at 6200 which is why power dumped. Didn't get a second pull because pipe blew off. Bumpy charts are not indicative of valve bounce. I doubt you would see it on a dynojet.

https://lh4.googleusercontent.com/-U...206_194802.jpg

Originally Posted by Unreal (Post 1585676283)

PRC 285 heads with SS exhaust TI intake for past 10k miles with the blower. Checked them before I moved and no sign of wear on a wiggle test. So far so good.

Originally Posted by Hib Halverson (Post 1585676544)

About that video...

I got my sectioned LS7 head off the shelf and took some rough measurements (ie: eyeball and ruler) of the part I have that's a sectioned exhaust port, half a chamber cut right down the CL of the exhaust guide.

Eyeballing the position of the dial indicator as shown in the video, then measuring half the guide (about an inch) plus the apprioximate distance from the guide down to the head of the valve, as shown in the video–say 3.75-in.–then, using trig, working out the difference between the observed clearance (.020) and what it would be if the measurement was taken in the proper place–it looks like the difference is a factor of about 3.8. That's huge.

So, to put it another way–if, measured the way it was done in that video, you saw .020" clearance, the actual stem-to-guide would be about .0053, which is well outside the Service max. tolerance of .0037

Nevertheless, I think I'd be careful with any conclusions you make if you measure stem-to-guide the way the video does. For example, let's say you saw .010 on the indicator, measuring the way it was done in the video. You might think OMG! But...the actual stem-to-guide would be .0026, well inside the Service tolerance and just a tenth outside the Production tolerance of .001-.0024.

Originally Posted by Unreal (Post 1585676283)

PRC 285 heads with SS exhaust TI intake for past 10k miles with the blower. Checked them before I moved and no sign of wear on a wiggle test. So far so good.

Originally Posted by bearcatt (Post 1585678334)

A little more information on your setup would be interesting.

Can one assume you have an aftermarket cam ?

Stock rocker arms or some type of roller rocker ?

Please do tell. :D



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