How’s my graph look? - Page 4 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

RGD · 03-10-2018, 05:13 PM

He just dropped my car off a few minutes ago, to bad it’s pouring rain out side and it’s not supposed to stop until tomorrow night! We talked for a few minutes but I am supposed to go by his shop after I drive it a little and we are going to fine tune everything. He is thinking I am running out of air so time for an intake, throttle body, and probably injectors.

Also, he thinks this is the graph when he hit the 150 mph speed limiter. He took it off after that.

Arch-City · 03-10-2018, 07:38 PM

Quote:

Originally Posted by RGD

Thanks. I am pretty sure they came out to 58cc after we cut 50 thousand off the heads.

What fuel are you running? Just wondering, because if the factory heads are 68cc and you are at 55cc now wouldn't that raise the compression by about 2.0 pts and put you at 12.5 compression and would be kinda high for 93 octane right?

Am I looking at all of this correct or by going the an aftermarket head does this change the compression numbers up.

Just trying to get an idea of your compression, because I thought about 11.7 to 12 was about all you could run on 93. Someone smarter than me please chime in and let me know. Thanks

RGD · 03-10-2018, 09:00 PM

Quote:

Originally Posted by Arch-City

What fuel are you running? Just wondering, because if the factory heads are 68cc and you are at 55cc now wouldn't that raise the compression by about 2.0 pts and put you at 12.5 compression and would be kinda high for 93 octane right?

Am I looking at all of this correct or by going the an aftermarket head does this change the compression numbers up.

Just trying to get an idea of your compression, because I thought about 11.7 to 12 was about all you could run on 93. Someone smarter than me please chime in and let me know. Thanks

According to the engine guy I should be between 11.5 and 12 and should be good to run 93. He did all the math, milling and ordered all my parts. I just did the work.

Arch-City · 03-10-2018, 09:17 PM

Quote:

Originally Posted by RGD

According to the engine guy I should be between 11.5 and 12 and should be good to run 93. He did all the math, milling and ordered all my parts. I just did the work.

That sounds about right for 93, I'm running 11.7 comp and can run 93. If it is available in your area you should try adding a flex fuel sensor and run some E85. I did and gained another 20 rwhp and about 18 tq, nice gains for the $. You have yourself a nice build going.

trw427ss · 03-10-2018, 09:20 PM

Quote:

Originally Posted by RGD

According to the engine guy I should be between 11.5 and 12 and should be good to run 93. He did all the math, milling and ordered all my parts. I just did the work.

If you have a 58cc head on a LS3 bottom end you have 12.25 compression!

Arch-City · 03-10-2018, 09:27 PM

Quote:

Originally Posted by trw427ss @ Futral

If you have a 58cc head on a LS3 bottom end you have 12.25 compression!

I thought 58cc was going to be more than 12. Isn't 12.25 a little dangerous on 93 octane fuel.

trw427ss · 03-10-2018, 09:40 PM

Quote:

Originally Posted by Arch-City

I thought 58cc was going to be more than 12. Isn't 12.25 a little dangerous on 93 octane fuel.

It depends on your tuner but it would be better on E85 and make a little more power!

Bo White · 03-11-2018, 03:22 PM

Also depends on how big the valve reliefs are in the piston on compression. Valve reliefs add volume.

Bo White · 03-11-2018, 03:22 PM

Factory heads are close to 70cc

RGD · 03-11-2018, 06:55 PM

No valve reliefs just factory flat top pistons. Also head gasket thickness will play a part in compression. Not sure how thick my gaskets are, like I said he picked all the parts I just did the work.

marklsx · 03-11-2018, 08:45 PM

I have a DCR calculator from 'PianoProdigy' from ls1tech - from maybe 10 years ago. The spreadsheet doesn't have the exact lobes but it gives a DCR of 8.7 which is OK on pump gas.

So basically you can run a high SCR as long as the cam has a lot of overlap to bleed off the cylinder pressure. And OP's cam is big.

03-11-2018, 03:22 PM	#50
Bo White Drives: 2015 Summit White 2SS 1LE Join Date: Feb 2012 Location: Vance Alabama Posts: 8,019	Also depends on how big the valve reliefs are in the piston on compression. Valve reliefs add volume. __________________ Retired wanna be cylinder head porter 2015 2SS 1LE Clutch reservoir, Vararam DRX, ported TB, TSP 2" headers, MGW shifter Totalled: 2010 1SS Wilkes Performance/Eagle 416 shortblock, TSP custom valvetrain, PRC 260 heads, Edelbrock Pro Flo 102, th400 swap, 8" PTC 5500 stall= 535/435 at the wheels tuned Gen 3 Performance and Dyno 10.97 @ 124 full weight in 3100 DA CamaroFest X

03-11-2018, 03:22 PM	#51
Bo White Drives: 2015 Summit White 2SS 1LE Join Date: Feb 2012 Location: Vance Alabama Posts: 8,019	Factory heads are close to 70cc __________________ Retired wanna be cylinder head porter 2015 2SS 1LE Clutch reservoir, Vararam DRX, ported TB, TSP 2" headers, MGW shifter Totalled: 2010 1SS Wilkes Performance/Eagle 416 shortblock, TSP custom valvetrain, PRC 260 heads, Edelbrock Pro Flo 102, th400 swap, 8" PTC 5500 stall= 535/435 at the wheels tuned Gen 3 Performance and Dyno 10.97 @ 124 full weight in 3100 DA CamaroFest X

03-11-2018, 08:45 PM	#53
marklsx Drives: 2014 Camaro 1SS Join Date: Jun 2010 Location: MA Posts: 103	I have a DCR calculator from 'PianoProdigy' from ls1tech - from maybe 10 years ago. The spreadsheet doesn't have the exact lobes but it gives a DCR of 8.7 which is OK on pump gas. So basically you can run a high SCR as long as the cam has a lot of overlap to bleed off the cylinder pressure. And OP's cam is big. __________________ 2014 1SS - BTR Stg3, GMPP CNC Heads, Kooks LTs & cats, Magnaflow 2.5" Street w/Res X, Z28 CAI

03-10-2018, 05:13 PM	#43
RGD Drives: 2010 2ss Join Date: Nov 2017 Location: Loganville GA Posts: 28	He just dropped my car off a few minutes ago, to bad it’s pouring rain out side and it’s not supposed to stop until tomorrow night! We talked for a few minutes but I am supposed to go by his shop after I drive it a little and we are going to fine tune everything. He is thinking I am running out of air so time for an intake, throttle body, and probably injectors. Also, he thinks this is the graph when he hit the 150 mph speed limiter. He took it off after that.

03-11-2018, 06:55 PM	#52
RGD Drives: 2010 2ss Join Date: Nov 2017 Location: Loganville GA Posts: 28	No valve reliefs just factory flat top pistons. Also head gasket thickness will play a part in compression. Not sure how thick my gaskets are, like I said he picked all the parts I just did the work.