octane difference worry? :: Triumph Torque

Triumph Parts Sign up for our Newsletter Rimmer Bros

Welcome, Guest.
Please login or register.
octane difference worry?
Forum Login
Login Name: Create a new account
Password:     Forgot password

Triumph Torque    Chit Chat Boards    Technical Chit-Chat  ›  octane difference worry?
Users Browsing Forum
No Members and 13 Guests

octane difference worry? Print
2 Pages 1 2 » All Recommend Thread
stomp
March 19, 2017, 9:02pm Report to Moderator

Posts: 2
Posts Per Day: 0.01
So possibly a silly but newby question,
I imported a GT6 MK1 (needs restoring) and MK2 immaculate Californian car, However I was wondering
if the difference in octane could cause any problems?
  kind regards
Dave
Logged
Private Message
GT6 M
March 19, 2017, 9:48pm Report to Moderator

Club Member
Posts: 5,802
Posts Per Day: 1.85
Yes, it,ll need 97

will most likely pink on 95

and maybe the cr is up too, cos valves, piston, chambers full of crud

Butt, mabe engine is so shot, ye got nee compressionee,
so maybe run ok on 95

ye really gotta try it first.

Butt, for the miles yer gonna doo,
what is a few quid extra a tank,or fill up

can waste that much on a Pie,or a pint,!!!

M


One does not have to know how a thing works, to know that it is not working right

Ye div,nt efta no ooa thing wuks, t,no its nut wuk,n reet.







Scaryport,��Cumbria,.
Logged
Private Message Reply: 1 - 16
bxbodger
March 20, 2017, 7:36am Report to Moderator

Posts: 919
Posts Per Day: 0.21
Wouldn't a US spec engine be already suited to a lower octane rating?


'68 Mk1 Vitesse convertible boneshaker, and a somewhat more economical '89 998cc A series powered Metro.
Logged
Private Message Reply: 2 - 16
glang
March 20, 2017, 8:11am Report to Moderator

Posts: 597
Posts Per Day: 0.61
sorry to hijack but Stomp what was the importation process like?
Logged
Private Message Reply: 3 - 16
nang
March 21, 2017, 5:01am Report to Moderator

Posts: 2,364
Posts Per Day: 0.68
Unfortunately, all my cars are addicted to 98. The best we can get over here. It seems USA run lower octane fuel which seems odd to me. Any comments anyone?
Tony.


If all else fails-Read the Instructions! ��Wairoa
New Zealand

1976 2500TC (converted to S spec) owned since 1998.

1999 BMW 2800 cc Z3 Convertible.
 
2003 BMW 525i Touring.
Logged
Private Message Reply: 4 - 16
dazzer
March 21, 2017, 8:07am Report to Moderator


Posts: 1,192
Posts Per Day: 0.37
For my high comp early six as used in my rally car i had the dizzy rebuilt by the Dizzy Doctor with a retarded curve. It runs fine on 95 no pinking whatsoever with no loss of power. Im sure you could create something similar with one of the mapped electronic systems if preferred. On weekend or night rallies in the sticks non of the rural fuel stations have anything other than 95 and it saves faffing with octane booster.


1965 2000 MK1 Rally project, HRCR rally championship, Hexham, 12 car night rallies, trials, autotests etc, etc.

1958 DKW 3-6 Coupe. Two stroke German rally contender, screaming demon! Where modern Audi originated from.

Logged
Private Message Reply: 5 - 16
Don Cook
March 21, 2017, 4:38pm Report to Moderator

Posts: 243
Posts Per Day: 0.15
"can waste that much on a Pie,or a pint,!!!" (SIC)

Wash your mouth out with soap and water!


Don Cook
Manningtree, Essex

GT6 Mk3 Signal Red (Tomboy). Triumphs in the past: Vitesse 1600, Toledo. Tiger Cub, Thunderbird.

Ten Countries Run 2003, 2005, 2007, 2009, 2011, 2015
Several Dutch Rallies.
Some La Carrera Caledonia.

Best trip ever: Ijsselmeer causeway then up through Germany, Denmark...over the two massive bridges of Slorebaeltbroen and Oresund to Ystad in Sweden where we got an overnight ferry to Poland, then on to Berlin etc.
Logged
Private Message Reply: 6 - 16
Howard
March 21, 2017, 7:21pm Report to Moderator

Club Member
Posts: 969
Posts Per Day: 0.27
97 normally has less ethanol which reduces the risk of damage to the rubber components and appears to have less of a problem with vapourisation at altitude (10CR runs through the alps) so I only use 97 in my 7



Le Mans 2007, 08, 09, 10 & 11
RBRR 2008(DNF), 10, 14, 16
10CR 2009, 11, 13, 15, 17
Logged Online
Private Message Reply: 7 - 16
glang
March 22, 2017, 7:30am Report to Moderator

Posts: 597
Posts Per Day: 0.61
Quoted from dazzer
For my high comp early six as used in my rally car i had the dizzy rebuilt by the Dizzy Doctor with a retarded curve. It runs fine on 95 no pinking whatsoever with no loss of power. Im sure you could create something similar with one of the mapped electronic systems if preferred. On weekend or night rallies in the sticks non of the rural fuel stations have anything other than 95 and it saves faffing with octane booster.


As I understand it there's nothing to be done with the ignition system that can help cos pinking is about the fuel charge detonating on its own before the spark arrives. There are a few possible causes but here were talking about if the CR is too high for the octane rating of the fuel where the only solutions would be lowering the CR or increasing the octane level to make it more resistant to self igniting....
Logged
Private Message Reply: 8 - 16
RobPearce
March 22, 2017, 9:31am Report to Moderator

Club Member
Posts: 1,731
Posts Per Day: 1.45
Quoted from glang
As I understand it there's nothing to be done with the ignition system that can help cos pinking is about the fuel charge detonating on its own before the spark arrives.


No.

This is a common misconception but it's simply not true1. Knock is the result of small pockets of fuel/air mix detonating under the combination of heat and sudden extreme pressure that comes about as the flame front bears down on them. The flame front itself must already exist, which happens as a result of the spark. If you retard the ignition, the flame front propagates later, meaning that the peak in-cylinder pressure happens further after TDC, in a bigger volume, and therefore at a lower pressure. This can be enough to prevent knock.



1 It may be possible to incur this sort of severe dieseling but if you ever did then the engine would run on something rotten.


Current fleet
1967 Vitesse 2L conv "Tessa"
1970 Spitfire Mk3 (project) "Toby"
1972 GT6 Mk3
Not enough time or space
Recently sold:
1972 2.5 PI estate "Harry" (gone to russell on here)
1973 Toledo 2-door "Spike" (gone to a club official)
Used to have:
1968 Vitesse 2L saloon
1980 Dolomite 1500
1977 Dolomite 1850
1980 Dolomite Sprint
1982 TR7 DHC Sprint
1975 2500S saloon
1971 Herald 13/60 Estate (with 1500 Spit engine)
1975 Stag
Logged
Private Message Reply: 9 - 16
glang
March 22, 2017, 12:19pm Report to Moderator

Posts: 597
Posts Per Day: 0.61
As I said 'theres a few possible causes' so I suppose the difficult part is identifying which is giving rise to the pinking in each particular case.....
Logged
Private Message Reply: 10 - 16
RobPearce
March 22, 2017, 12:41pm Report to Moderator

Club Member
Posts: 1,731
Posts Per Day: 1.45
No, glang, those "other causes" are not the point. They are merely contributory factors towards achieving the conditions whereby the flame front causes localised detonation. Putting low octane fuel in a high compression engine does not make it diesel unless you go outside the bounds of normal use. Perhaps 80 octane in a 15:1 compression would diesel but 95 RON in a GT6 Mk1 HE engine can be tolerated by retarding the ignition.

If you think about it, typical compression ratios are between 8:1 and 11:1 - a spread of under 50% from min to max. When the spark goes off, the flame front begins at the plug and propagates, expanding that gas by a large factor. The residual gas in corners thus gets further compressed by at least 3:1. That means it's experiencing the equivalent of a 30:1 compression ratio before "self-ignition".

Again, I reiterate: pinking is NOT unattended self-ignition without the spark. It's a localised effect resulting from the aftermath of the spark. It can be prevented by removing any of the contributory factors or by retarding to reduce the peak pressure.


Current fleet
1967 Vitesse 2L conv "Tessa"
1970 Spitfire Mk3 (project) "Toby"
1972 GT6 Mk3
Not enough time or space
Recently sold:
1972 2.5 PI estate "Harry" (gone to russell on here)
1973 Toledo 2-door "Spike" (gone to a club official)
Used to have:
1968 Vitesse 2L saloon
1980 Dolomite 1500
1977 Dolomite 1850
1980 Dolomite Sprint
1982 TR7 DHC Sprint
1975 2500S saloon
1971 Herald 13/60 Estate (with 1500 Spit engine)
1975 Stag
Logged
Private Message Reply: 11 - 16
glang
March 22, 2017, 2:09pm Report to Moderator

Posts: 597
Posts Per Day: 0.61
ok mate
Logged
Private Message Reply: 12 - 16
Jonny-Jimbo
March 22, 2017, 3:05pm Report to Moderator

Club Member
Posts: 4,973
Posts Per Day: 1.23
Quoted from nang
Unfortunately, all my cars are addicted to 98. The best we can get over here. It seems USA run lower octane fuel which seems odd to me. Any comments anyone?
Tony.


The US and Canada have a different rating scale, which means the octane rating for identical fuel can be different.

In the UK (and most of the world) the octane rating on the pump is 'RON', but in the US and Canada they use the average of RON and MON octane ratings, so something sold as 89 in the US and Canada could be the same as 95 in the rest of the world.


62 Vitesse 1600 - Slammed & modified
67 2000 - Fitted with 2.5 o/d - 2012 RBRR, 2015 Essex Rally, 2016 HCR, 2016 RBRR
67 2000 Estate - Dormant
70 Herald 13/60 - First car, many bits
77 CZ 125 Sport - 70 miles on the clock
77 Kawasaki KM90 - Shop hack
81 Yamaha DT125 - Many bits
88 Ginetta G4/4 - Dead
88 BMW E30 320i - For Sale
89 Citroen AX GT - Rally car!
90 BMW E30 318iS - Building to FIA spec
90 Mazda Eunos 1.6 - 'Popeye'
93 BMW 530i - Donor
95 BMW E34 540i - 4L V8
Logged Online
Private Message Reply: 13 - 16
glang
March 22, 2017, 4:22pm Report to Moderator

Posts: 597
Posts Per Day: 0.61
didnt know that Jonny but did you mean 89 or 98 sold in US and Canada?
Logged
Private Message Reply: 14 - 16
2 Pages 1 2 » All Recommend Thread
Print

Triumph Torque    Chit Chat Boards    Technical Chit-Chat  ›  octane difference worry?

Thread Rating
There is currently no rating for this thread
 


Powered by E-Blah Forum Software 10.3.5 © 2001-2008

Latest Blogs-
Steve Weblin

18th November 2017 08:30am gmt
Standard car dealers in India
The Viper's Nest

20th October 2017 7:19pm gmt
Where it all began…
more blogs...
Next Group Meetings-
Worcestershire Wednesday 22nd November 20:00
Nottingham Monday 27th November 19:00
Essex Tuesday 28th November 20:00
Cheshire & Staffs Wednesday 29th November 19:30
Coventry & Warwickshire Wednesday 29th November 19:30
Northern Ireland Wednesday 29th November 20:00
more local groups...
Upcoming Events-
CMC Mince Pie 12 Car Rally
24th November 2017
BCC Santa Rally
10th December 2017
more events...
For Sale-
Pair of Stromberg CD 175 carburettors, linkage and mounting nuts. Removed from an American-spec TR6. Looking for £35. Based in Peterborough. Matt George on the forum or phone 07921 853482.
project colander aka 1973 1500tc dolomite - needs lots of welding but is largely complete though partly dismantled . contact dinger on the forum

1966 Herald Convertible 1200 cc Dismantled. SORN and V5 £600 Buyer collect Cambs/Beds border SG19 Contact mickandmave@outl ook.com
more adverts...
CLUB TRIUMPH the Club for all Triumphs
© Club Triumph Ltd MCMXCVI - MMXV