Katech LS7 Valvetrain Dynamics testing approved - seeking input from Corvette Forum
 

Good news. I have received budget approval to run a valvetrain dynamics test for development purposes to prove out a few of the questions posed here on the forum. Before I write the test plan, I'm interested in hearing input from you guys to see if there are additional combinations that need testing. I'm not saying that every combination posted here will get tested, or any additional at all, but your suggestions will be considered.

We would like to run this test as soon as possible. The valvetrain test cell is currently down due to computer problems, but repairs are in progress that should get it back up and running within days. Because it was down there is a bit of a backup of programs that are waiting for testing so we will have to wait in line, but once it gets fixed that should go through smoothly. In other words, I can't guarantee exactly when, but it will get done soon.

Here is how I see the test plan:
1. Stock cam/springs, stock valves
2. Stock cam/springs, solid stainless exhaust valve
3. Stock cam/dual springs, solid stainless exhaust valve
4. Torquer cam/PSI springs, stock valves (already tested long ago, but we will baseline again)
5. Torquer cam/PSI springs, solid stainless exhaust valves
6. Torquer cam/dual springs, solid stainless exhaust valves
7. Torquer cam/PSI springs, Ti exhaust valve

The Torquer cam will be an example of your typical aftermarket cam lobe profile.

RESULTS:


06/19/13

I have partial results:

Consideration for when a valve is out of control is subject to debate, however .015" of bounce is the basis we will use these recommendations. Keep in mind that we only tested for limiting speeds and did not perform durability testing. If this were a pro race program we would go back to the tests we want and run 24-100 hours of durability on the configuration to see what breaks if anything. Obviously we're not going to do that here due to budget constraints.

1. Stock cam/springs, stock valves
INTAKE: .006" max bounce @ 7000RPM, tested up to 7500RPM
EXHAUST .008" max bounce @ 7100RPM, tested up to 7500RPM
Install height: 1.950"
Seat: 113#
Open: 323#

2. Stock cam/springs, solid stainless exhaust valve
INTAKE: see configuration 1
EXHAUST: .015" max bounce @ 7100RPM, tested up to 7500RPM
Install height: 1.950"
Seat: 113#
Open: 323#
Katech's recommendation: This combination is fine for a street car if you set your rev limiter to 7000RPM. In road racing conditions we prefer to see 500-800RPM of safety margin so if you plan on road racing with this combination our recommendation is to set the rev limiter to 6300-6600RPM.

3. Stock cam/dual springs, solid stainless exhaust valve
INTAKE: .014" max bounce @ 7300RPM, tested up to 7500RPM
EXHAUST: .016" max bounce @ 7200RPM, tested up to 7500RPM
Install height: 1.700"
Seat: 187#
Open: 417#
Katech's recommendation: This combination is fine for a street car if you set your rev limiter to 7000RPM. If road racing, set the rev limiter to 6400-6700RPM.

4. Torquer cam/PSI springs, stock valves
INTAKE:
EXHAUST: .015" max bounce @ 7700RPM, tested up to 7700RPM
Install height:
Seat:
Open:
Katech's recommendation: This combination is proven and stable. Keep fuel cut at 7100 though.

5. Torquer cam/PSI springs, solid stainless exhaust valves
INTAKE:
EXHAUST: .014" max bounce @ 6800RPM, tested up to 7100RPM
Install height:
Seat:
Open:
Katech's recommendation: This combination is not recommended, although the PSI spring did control the Rev valve better than the dual spring.

6. Torquer cam/dual springs, solid stainless exhaust valves
INTAKE:
EXHAUST: .029" max bounce @ 7100RPM, tested up to 7100RPM
Install height:
Seat:
Open:
Katech's recommendation: This combination is not recommended.

7. Torquer cam/PSI springs, Ti exhaust valve
INTAKE:
EXHAUST: .014" max bounce @ 7900RPM, tested up to 7900RPM
Install height:
Seat:
Open:
Katech's recommendation: This combination is excellent all the way up to 7800RPM.

As a surprise there were actually more configurations tested. The camshaft that was used in Halltech's recent project will be a new offering from Katech as a step up from the Torquer 110. We used this opportunity to test this configuration and the results were a very smooth valvetrain. We are very happy with it.

8. K501 cam/PSI springs/stock valves
INTAKE: .010" max bounce @ 7800RPM, tested to 7800RPM
EXHAUST: .010" max bounce @ 7200RPM, tested to 7700RPM
Install height: 1.750" intake / 1.800" exhaust
Seat: 161# intake / 140# exhaust
Open: 404# intake / 379# exhaust
Katech's recommendation: This combination is excellent for road race or street use. Recommended redline is 7300RPM assuming although due to high piston speed with a 4.000" stroke for road racing use the redline should still be 7000RPM.

9. K501 cam/PSI springs/stock (or Katech Ti/Mo - same weight) intake valves, Katech Ti/Mo exhaust valves
INTAKE: see configuration 8
EXHAUST: Double bounce - .011" @ 7300RPM & .010" @ 7700RPM, tested to 7800RPM
Install height: 1.750" intake / 1.800" exhaust
Seat: 161# intake / 140# exhaust
Open: 404# intake / 379# exhaust


Springs used:
PSI - LS1511 w/Katech Ti retainers
Dual: BT Platinum dual spring kit with Ti retainers
Stock LS7 with stock LS7 retainers

Valves:
OEM intake: 80g
OEM Exhaust: 74g
Rev Exhaust: 98g
Katech Ti Exhaust: 66g

https://fbcdn-sphotos-g-a.akamaihd.n...84341770_o.jpg
https://sphotos-a.xx.fbcdn.net/hphot...14041069_o.jpg

Subscribed! :thumbs:

thanks for doing this and sharing with us. I know this can't be inexpensive to do.

How about adding Ti spring retainers to the mix since it is a common upgrade? (and recommended with the torquer cam) I'm wondering if that may help with the heavier stainless valves too?

Yes, anywhere you see PSI springs on that list would be with Ti retainers. They are required to get the install height we need.

I'm VERY interested. How is this testing performed and what information does it provide? Can it show the durability difference between OE and bronze valve guides? If so, I'd suggest adding that factor.

I see the test plan, what are you looking for during the test? Some what confused...

#5 and #6 Please.

I would like to see what combination works with Lingenfelter's GT9 camshaft.

http://image.gmhightechperformance.c...valvetrain.jpg

Great question. Cell 1 is a valvetrain motoring cell. We use a 30hp electric motor to drive a "buck". The buck is basically a dummy engine that just drives the valvetrain. It consists of a block with a hole cut in the side of one of the cylinders and a dummy crankshaft with no connecting rods, pistons or bobweights. The crankshaft drives the timing gear, camshaft and valvetrain on one cylinder. We point a laser at the valves through the hole in the side of the block. The laser send the data of the valve's movement to a computer and we can plot it out on a graph. We can plot bounce as the valve closes and loft (aka float) over the nose of the camshaft. This is used to determine limiting speed. We can also run destructive testing to determine durability. During development of the C5-R race program we proved the valvetrain out for 30 hours before running the 24 Hours of Le Mans. Any time you change one component in the valvetrain the entire system needs to be tested again.

There was a good article written a few years ago in GM High Tech that explains more.
http://www.gmhightechperformance.com...e/viewall.html

Sorry, I didn't answer the second half of your question.

The testing is dynamics only. We will not be running durability. That requires exponentially higher budget.

Hi Jason, It would be great to also see one other spring that has a heavier seat pressure such as the Manley 221435-16 SBC LS Series. I would be willing to put some dollars towards obtaining a set.

Wow, I could come up with a couple dozen different scenarios..... What spin rig will you be using?

I would LOVE to see some testing with different rocker options, including rail set ups. The rail systems would obviously require a different modified head, but that data would be quite informative and possibly an option for Katech to sell as a head "upgrade" option. Crower, Jesel, T/D, Comp. The YT bolt on roller tip rockers are also getting a lot of free advertisement on this sight, so I suspect many CF members will be moving to them.

Are the PSI springs beehive? Which series?

Another test that would be interesting is a test with some double taper 1/2" and 5/8" push rods verse stock.

A test with different push rod pre-loads would be cool. One with .100" and one at .050".

A test with OE lifters, one with caddy lifters and one with some light weight / short travel morels.....

The dual spring used with the solid stainless valve will be heavier seat pressure to be matched with the heavier valve. Brand is TBD.

The beauty of valvetrain testing is you only have to buy one cylinder's worth of parts rather than a complete set.

Hi Jason,
Sounds like a great opportunity.....

What is your overall goal for this project?

That may help me/us frame our comments and requests..

Any direct data like this is much appreciated.
B

interested in hearing the results from tests: 3 and 6
subscribing

It's clearer now. Looking forward to seeing this test.

Can't wait to see what brand TBD. FWIW I'd humbly suggest something with installed seat pressure of ~150 lbs and open pressure ~400lbs. That would be in the ball park of most dual spring setups folks seem to be running on the forum.

I'm excited to see the results, thank you for planning this. :thumbs:

:lurk:

Great that you are doing this and post ing now so there is a positive thread to read once in a while.

Wouldn't the absence of heat from combustion have a huge effect on how the valve train operates in this kind f test vs real life?

Sorry if that's a dumb question as I know you validated the C5R system.

:cheers:

WWWOOOO!!! excellent, this is going to help a lot of people sleep at night jason. Thanks for doing this, i'm sure the "verified" springs you guys test will sell like hotcakes.

I know valvetrain dynamics are a funny thing, but do you think this testing will show the predicted limits of redline/spring pressures for aggressive cam profiles as well?? If not, could we toss one of the more radical comp grinds in there for another data point??

Really looking forward to the findings, and some high speed footage of what is going on in there with the heavier valves.