octane & duration ?

Reply Subscribe

Thread Tools

Search this Thread

Jan 13, 2018 | 03:02 AM

ls1 trex

Thread Starter

Staging Lane

Joined: Dec 2011

Posts: 55

Likes: 0

octane & duration ?

hi guys

i want to know about duration

is it true ?

low duration means needs more octane

high duration means needs low octane

Jan 13, 2018 | 07:57 AM

HCI2000SS

TECH Senior Member

iTrader: (2)

Joined: Aug 2012

Posts: 11,137

Likes: 20

From: Howell & Fenton MI

Duration of what?

Jan 13, 2018 | 08:23 AM

ls1 trex

Thread Starter

Staging Lane

Joined: Dec 2011

Posts: 55

Likes: 0

for camshaft

Jan 13, 2018 | 08:28 AM

HCI2000SS

TECH Senior Member

iTrader: (2)

Joined: Aug 2012

Posts: 11,137

Likes: 20

From: Howell & Fenton MI

Not with the cams that we run for our cars

Jan 13, 2018 | 09:05 AM

ls1 trex

Thread Starter

Staging Lane

Joined: Dec 2011

Posts: 55

Likes: 0

like this simple

is it that cam shaft

225/236 .629"/.615"

need more octane than

235/248 .649"/.615"

Jan 13, 2018 | 09:09 AM

HCI2000SS

TECH Senior Member

iTrader: (2)

Joined: Aug 2012

Posts: 11,137

Likes: 20

From: Howell & Fenton MI

Nope it's not going to make hardly any difference all on its own

Jan 14, 2018 | 10:12 AM

.boB

TECH Resident

iTrader: (1)

Joined: Jan 2014

Posts: 897

Likes: 33

From: Colorado Springs, CO

Quote:

Originally Posted by ls1 trex

hi guys

i want to know about duration

is it true ?

low duration means needs more octane

high duration means needs low octane

Sort of. More duration means the intake valve is open longer, and usually means it closes later in the cycle. That means it will increase dynamic compression and cylinder pressure. That's kinda the point, because that's how you make power. To prevent detonation, you would want to use a higher octane fuel.

But as said above, the example you've given in an otherwise stock engine probably won't be a big enough change to matter all by itself.

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Brett Foote

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Pouria Savadkouei

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Verdad Gallardo

7 Most Reliable High-Performance Engines GM Has Ever Built

Verdad Gallardo

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Verdad Gallardo

6 Common C5 Corvette Failures and What's Involved In Repairing Them

Pouria Savadkouei

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Verdad Gallardo

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Pouria Savadkouei

Top 10 Most Powerful Chevy Trucks Ever Made!

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Verdad Gallardo

Jan 14, 2018 | 12:17 PM

Crf450r420

TECH Fanatic

iTrader: (1)

Joined: Apr 2013

Posts: 1,099

Likes: 5

From: Florida

Look up dynamic compression and that will help show you see how that is correct. The closer the intake closes to BDC the move volume that is compressed in the cylinder and the more that will heat up when compressed.

Jan 14, 2018 | 11:26 PM

#10

ls1 trex

Thread Starter

Staging Lane

Joined: Dec 2011

Posts: 55

Likes: 0

thanks guys ,,

Jan 20, 2020 | 09:54 PM

#11

qwiketz

Launching!

Joined: Feb 2008

Posts: 235

Likes: 1

any updates on this one? I just paid about $12.xx a gallon for sunoco 260 plus... Wondering if this is really pricey or basically the norm these days.