Cam + piston opinions

FKeller · 09-05-2021, 11:32 PM

Hey all,
Currently in the middle of a full build after a unfortunate front cover bolt mishap during the cam job ruined my stock #1 piston and block. I have a 18 1LE with ARH headers, lt2 intake, e85, and a tiny cam from cam motion. Currently purchasing BTR drop in pistons, however Going further into reading I found that the BTR pistons also raise CR to 11.7 from the regular 11.5. Being that the cam is a 218/228 with lift at .594/.585, would I benefit at all from the higher compression? More importantly the car is currently my daily, mostly did the cam to delete the afm, would the higher CR combined with the cam lower the drivability around town? Looking for opinions from those engine gurus here, I’m sure someone knows more about it than me.

Thanks for the help in advance

Puddin · 09-06-2021, 01:05 AM

What's the Lsa on the cam? The slight bump in compression isn't going mess with the drivability.

FKeller · 09-06-2021, 06:25 AM

Forgot to add that, Lsa is 114+5. I think what I’m really asking is with the high CR, will it affect the low end ability I.E. 6th at 60@ 1400-1500. As it is the car seemed to be ok with the cam at that low rpm highway cruising speed. However I’m concerned with the increased CR there will be a higher knock count at the low rpm high load, or so my limited knowledge with this platform seems to point to.

Spaceme1117 · 09-06-2021, 06:52 AM

Drivability should be fine. That is a mild cam.

And CR of 11.7 is not much of a bump. So no problem there either. Might help make a little bit more power on E85 but not much.

Joshinator99 · 09-06-2021, 07:18 AM

Quote:

Originally Posted by Spaceme1117

Drivability should be fine. That is a mild cam.

And CR of 11.7 is not much of a bump. So no problem there either. Might help make a little bit more power on E85 but not much.

Agreed.

95 imp · 09-06-2021, 08:50 AM

Not enough to worry about.

KingLT1 · 09-06-2021, 09:04 AM

If you are running E85 you could probably run 12.5:1 compression on the mild cam and not have to worry about knock due to high DCR. E loves high compression...I ran 11.5:1 on pump 93 with my H/C/I Ls1 4th gen and didn't have any issues with knock. The cam was a mild 224/228 112. While it is larger then what you are planning on running, PFI doesn't allow as high of compression at the same octane fuel as DI.

Moral of the story, you will be fine.

FKeller · 09-06-2021, 10:52 AM

It’s good to hear all of this, sounds like I’m going to be keeping the order in, thanks for the help guys!

JANNETTYRACING · 09-08-2021, 08:29 AM

Quote:

Originally Posted by FKeller

Hey all,
Currently in the middle of a full build after a unfortunate front cover bolt mishap during the cam job ruined my stock #1 piston and block. I have a 18 1LE with ARH headers, lt2 intake, e85, and a tiny cam from cam motion. Currently purchasing BTR drop in pistons, however Going further into reading I found that the BTR pistons also raise CR to 11.7 from the regular 11.5. Being that the cam is a 218/228 with lift at .594/.585, would I benefit at all from the higher compression? More importantly the car is currently my daily, mostly did the cam to delete the afm, would the higher CR combined with the cam lower the drivability around town? Looking for opinions from those engine gurus here, I’m sure someone knows more about it than me.

Thanks for the help in advance

Drivability is all in the tune so the parts will not be an issue.

Ted.

09-06-2021, 06:25 AM	#3
FKeller Drives: 2018 2SS 1LE Join Date: Nov 2020 Location: Miami Posts: 50	Forgot to add that, Lsa is 114+5. I think what I’m really asking is with the high CR, will it affect the low end ability I.E. 6th at 60@ 1400-1500. As it is the car seemed to be ok with the cam at that low rpm highway cruising speed. However I’m concerned with the increased CR there will be a higher knock count at the low rpm high load, or so my limited knowledge with this platform seems to point to. Last edited by FKeller; 09-06-2021 at 06:55 AM.

09-06-2021, 08:50 AM	#6
95 imp Dumb Ass Deluxe Drives: A Tricked Out Mountain Bike Join Date: Jun 2019 Location: Arizona Posts: 1,959	Not enough to worry about. __________________

09-06-2021, 09:04 AM	#7
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,797	If you are running E85 you could probably run 12.5:1 compression on the mild cam and not have to worry about knock due to high DCR. E loves high compression...I ran 11.5:1 on pump 93 with my H/C/I Ls1 4th gen and didn't have any issues with knock. The cam was a mild 224/228 112. While it is larger then what you are planning on running, PFI doesn't allow as high of compression at the same octane fuel as DI. Moral of the story, you will be fine. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

09-05-2021, 11:32 PM	#1
FKeller Drives: 2018 2SS 1LE Join Date: Nov 2020 Location: Miami Posts: 50	Cam + piston opinions Hey all, Currently in the middle of a full build after a unfortunate front cover bolt mishap during the cam job ruined my stock #1 piston and block. I have a 18 1LE with ARH headers, lt2 intake, e85, and a tiny cam from cam motion. Currently purchasing BTR drop in pistons, however Going further into reading I found that the BTR pistons also raise CR to 11.7 from the regular 11.5. Being that the cam is a 218/228 with lift at .594/.585, would I benefit at all from the higher compression? More importantly the car is currently my daily, mostly did the cam to delete the afm, would the higher CR combined with the cam lower the drivability around town? Looking for opinions from those engine gurus here, I’m sure someone knows more about it than me. Thanks for the help in advance

09-06-2021, 01:05 AM	#2
Puddin Drives: 2016 Camaro 2SS Join Date: Apr 2018 Location: Central Texas Posts: 1,011	What's the Lsa on the cam? The slight bump in compression isn't going mess with the drivability.

09-06-2021, 06:52 AM	#4
Spaceme1117 Drives: 2017 Camaro SS, 2011 Corvette GS Join Date: Feb 2019 Location: Erlanger, Kentucky 41018 Posts: 815	Drivability should be fine. That is a mild cam. And CR of 11.7 is not much of a bump. So no problem there either. Might help make a little bit more power on E85 but not much.

09-06-2021, 10:52 AM	#8
FKeller Drives: 2018 2SS 1LE Join Date: Nov 2020 Location: Miami Posts: 50	It’s good to hear all of this, sounds like I’m going to be keeping the order in, thanks for the help guys!

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