I'm sure this has been repeated many times but does anyone have any experience with Octane Boost? Use it regularly? won't touch it with a barge pole? why not etc. Stay with me on this, I'm gona need to waffle a bit to make my point clear...
I have very little experience with it but have recently tried a bottle and noticed a difference...
My 383 Charger runs best from 98 RON usually Optimax, and is notably lumpier when I'm forced to use 95RON! I was recommended to carry a couple of bottles of "Millers Octane Plus" in case I was forced to use 95RON; Millers adds 2RON to a 50ltr tank, so approx a bottle and a half applied to the Charger's empty tank makes your 95RON - 98RON, no surprises there!!!
However, for some reason in the back of my mind I was last told that due to the compression ration of my car etc. I'd be better running it on 100RON so I obviously got my Millers out, whacked it in and filled up with 98RON and the difference was very noticeable!!!
So this got me thinking and I started to do some research and tracked down "SUNOCO SUPREME (114RON, 110MON) - Leaded" racing fuel... Now after a quick chat with a supplier who seemed very knowledgeable, ex-racing experience etc. between us we worked out that mixing approx 10% of the 114RON racing fuel with a tank of 98RON pump gas would give 100RON and work out better and a lot cheaper than adding "Millers" it's also Leaded fuel so in the same application you get a mix of Valve Seat protection thrown in as well...
What are everyone?s thoughts on this kind of stuff... I've gota admit, I'm confused as to the implications, apart from cost of messing with this stuff... Fuel additives etc. hasn't bothered me at all for 4 years, I've been running the Charger on 98RON pump gas and everything?s been sweet... But recently I've added the odd mix of Lead replacement but now that I?ve tried the Octane boost and noticed a difference in how crisper the engine revs through the range it's got me thinking I should be mixing my fuel to 100RON?
What do you say???
Fuel Additives - Octane Boost
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Dave-R
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It depends what your cylinder pressure actually is (effected by compression ratio and valve timing) and what your spark advance curve is like (esp. total advance).
I see no reason for octane booster if the engine is tuned right unless it really is a race engine with wild compression and timing advance.
I see no reason for octane booster if the engine is tuned right unless it really is a race engine with wild compression and timing advance.
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Anonymous
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Anonymous
As Dave says a distributor that has the correct timing events for the motor/car and application, which by the way a standard Mopar unit isn't.
If it's points bin it unless it's got to be stock looking in which case we can put the electronic deal inside a points distributor, well FBO can
, if it's electronic it needs to be custom curved.
The Mopar orange box is U/S and drops way to many sparks
we can supply the whole kit
If it's points bin it unless it's got to be stock looking in which case we can put the electronic deal inside a points distributor, well FBO can
, if it's electronic it needs to be custom curved.The Mopar orange box is U/S and drops way to many sparks
we can supply the whole kit
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Anonymous
I use regular unleaded plus Catrol lead replacement incl. octane boost on the street just for the reassurance. I use Optimax plus an Octane booster at the track just for the reassurance of running lots of timing and not being able to hear any detonation over the open headers inside my helmet... There is a thread on curving yer Dizzy somewhere under tach.
<center>
The name is Kev, nowadays known as Kevvy or Pommie C***!</center>
The name is Kev, nowadays known as Kevvy or Pommie C***!</center>
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Anonymous
two ways mate
either send the distributor to me I then send it to FBO
or
FBO curve one and send it over and you send the old one back to me afterwards.
Would need a spec sheet filled in which is on our site www.usaimports.co.uk with ALL relevant information, without the info it's not a custom curve.
We do three, stage 1 with the vac can, stage 2 without the vac can and stage 3 locked, you get whichever one fits the info on the spec sheet.
stage 1 total street car where mileage is important
stage2 street/strip where no one gives a monkeys about mileage
stage 3 race
all these are good up to about 240*@ 0.50 cam duration and 12:1 comp after that you need a MSD, even with an MSD the odds are you need the total limit bushes
If the car/application suits then the stage 2 is the best as this gets rid of the wobbly baseplate which does NOT keep timing accurate in a mopar distributor
The custom curve means you set the initial at whatever it says on the ticket with the distributor, the curve is set with the springs at FBO to be just right and the total is limited to the correct * more often than not around 34*, FBO now have a new design so the total is now fully adjustable anyway, if it's got a vac can that will be set correct for the application
So you end up with a fully adjustable distributor thats right for the application as it is now, if anything changes a quick spring change will bring the curve into line and the total is adjustable be means of 2 small screws, if it's got a can then thats adjustable anyway.
It goes without saying that any changes needed in the future we will supply the figures required.
Any part we supply we will assist in any tuning issues, come to think of it any part we don't supply too
well as long as the parts not chinese junk in the first place
We will only take mopar electronic distributors as the core charge
either send the distributor to me I then send it to FBO
or
FBO curve one and send it over and you send the old one back to me afterwards.
Would need a spec sheet filled in which is on our site www.usaimports.co.uk with ALL relevant information, without the info it's not a custom curve.
We do three, stage 1 with the vac can, stage 2 without the vac can and stage 3 locked, you get whichever one fits the info on the spec sheet.
stage 1 total street car where mileage is important
stage2 street/strip where no one gives a monkeys about mileage
stage 3 race
all these are good up to about 240*@ 0.50 cam duration and 12:1 comp after that you need a MSD, even with an MSD the odds are you need the total limit bushes
If the car/application suits then the stage 2 is the best as this gets rid of the wobbly baseplate which does NOT keep timing accurate in a mopar distributor
The custom curve means you set the initial at whatever it says on the ticket with the distributor, the curve is set with the springs at FBO to be just right and the total is limited to the correct * more often than not around 34*, FBO now have a new design so the total is now fully adjustable anyway, if it's got a vac can that will be set correct for the application
So you end up with a fully adjustable distributor thats right for the application as it is now, if anything changes a quick spring change will bring the curve into line and the total is adjustable be means of 2 small screws, if it's got a can then thats adjustable anyway.
It goes without saying that any changes needed in the future we will supply the figures required.
Any part we supply we will assist in any tuning issues, come to think of it any part we don't supply too
well as long as the parts not chinese junk in the first placeWe will only take mopar electronic distributors as the core charge
Just to echo the given advice. Most usually I think Octane booster is used when ignition advance is not optimised (not always but often).
People often think that high octane fuel (or octane booster) is somehow more powerful, like a super fuel. Octane is literally the fuel's resistance to knock. If you are not already knocking then higher octane fuel will not give you any advantage at all (other than less weight to carry in your back pocket). If you are at your knock limit then using a higher octane fuel and advancing the timing can get extra power & economy
So if just using higher octane fuel makes the car run better then either you were knocking but not able to hear it, or I suppose conceivably there could be some other additives (not octane boost) in there that are enhancing a poor combustion process. Not sure what they would be but just thinking aloud.
So generally, unless you've got LOTS of combustion pressure (mostly high compression ratio but also depends on cam, chamber geometry, etc) you should not need the high octane. Certainly as a rule of thumb, at less than 10:1 there is no reason you should need it, above that it depends on how well your engine works as a unit.
Not news to many I realise but worth restating since this topic does crop up from time to time.
People often think that high octane fuel (or octane booster) is somehow more powerful, like a super fuel. Octane is literally the fuel's resistance to knock. If you are not already knocking then higher octane fuel will not give you any advantage at all (other than less weight to carry in your back pocket
). If you are at your knock limit then using a higher octane fuel and advancing the timing can get extra power & economySo if just using higher octane fuel makes the car run better then either you were knocking but not able to hear it, or I suppose conceivably there could be some other additives (not octane boost) in there that are enhancing a poor combustion process. Not sure what they would be but just thinking aloud.
So generally, unless you've got LOTS of combustion pressure (mostly high compression ratio but also depends on cam, chamber geometry, etc) you should not need the high octane. Certainly as a rule of thumb, at less than 10:1 there is no reason you should need it, above that it depends on how well your engine works as a unit.
Not news to many I realise but worth restating since this topic does crop up from time to time.
Gavin Chisholm - 414ci W2 Stroker SmallBlock Panther Pink '71 Challenger convertible - in bits
Car progress can be viewed here
Car progress can be viewed here
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Anonymous
To find the initial creep the timing up until it wants to knock the nose off of the starter JUST then go back 2*, that's as close a guess your going to get. You want as much initial as is possible without breaking the starter as the peak flame front wants to be starting about 12/15*after TDC
The above then messes the advance curve up which needs sorting out
With modern fuels thats going to put the total way out on a stock distributor and you will get detonation, that's why the entire mechanical timing needs to be restricted, the vac can if needed adds mileage but also adds problems of it's own.
As Gavin says if the car runs better with OB and no timing adjustments then it's detonating or very close.
No doubt somebody will say i'm talking rubbish
but if one of our distributors doesn't sort the job out then i'll take it back
It ought to kick the starter at around 20/22* maybe a little more, try it carefully with a dial back light and then check where the total is i bet it's more than 34* which is where most want to be total, this is with the can disconnected and plugged at the carb.
In the previous FBO total limit design the slots were welded to limit total now this usually meant around 1/8" of weld at least in the slots, this is because we want a good amount of initial but not the corresponding total and thats never mind the can which will add a bazzilion * if not set right
And the other problem is carb settings which can make a curve totally useless, Ignition first with the correct figures then carb tuning
The above then messes the advance curve up which needs sorting out
With modern fuels thats going to put the total way out on a stock distributor and you will get detonation, that's why the entire mechanical timing needs to be restricted, the vac can if needed adds mileage but also adds problems of it's own.
As Gavin says if the car runs better with OB and no timing adjustments then it's detonating or very close.
No doubt somebody will say i'm talking rubbish
but if one of our distributors doesn't sort the job out then i'll take it backIt ought to kick the starter at around 20/22* maybe a little more, try it carefully with a dial back light and then check where the total is i bet it's more than 34* which is where most want to be total, this is with the can disconnected and plugged at the carb.
In the previous FBO total limit design the slots were welded to limit total now this usually meant around 1/8" of weld at least in the slots, this is because we want a good amount of initial but not the corresponding total and thats never mind the can which will add a bazzilion * if not set right
And the other problem is carb settings which can make a curve totally useless, Ignition first with the correct figures then carb tuning
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Anonymous
Alex most every distributor that Don does is 34* or thereabouts both SB &BB, never seen one yet thats 38, i'm not saying that some wouldn't like 38, but the majority don't.
Wildmans charger for instance 19* initial 34* total all in at 3100rpm, this was when we were fitting the dual stall convertor so the total is in a little before the higher stall
Yes you will lose a little compared to what power these things were making when good fuel was available but it isn't now and a motor that has no detonation will always make more power, different story on a race car as fuel costs aren't that important or put another way the quest for the last bit of power outways the cost of race fuel at some point.
38 is high for total but you can't back it down without taking the initial down too unless you have adjustable limits, same as the limit bushes in an MSD, all motors do not want the same timing
Wildmans charger for instance 19* initial 34* total all in at 3100rpm, this was when we were fitting the dual stall convertor so the total is in a little before the higher stall
Yes you will lose a little compared to what power these things were making when good fuel was available but it isn't now and a motor that has no detonation will always make more power, different story on a race car as fuel costs aren't that important or put another way the quest for the last bit of power outways the cost of race fuel at some point.
38 is high for total but you can't back it down without taking the initial down too unless you have adjustable limits, same as the limit bushes in an MSD, all motors do not want the same timing
Don't get me wrong mate, I agree with what you are saying and I know Don does good product, what I was wondering was why he chose 34 deg, I always set sb's at 34 as they seem really happy around there give or take 1 or 2, but in the 20 odd years I have been working these things it has been fairly written in stone that a BB likes 38 or so.
When I get some cash I intend to talk to you about going all FBO ignition so that should prove I both support you and I approve of the product.
At the mo the Runner is at 12 in and 37 total, I may lose or gain a few degrees if I get some track time as I have had no time at all to do anything on this car as I have been building BB mopars and sb mustang motors almost non stop!
I will pop over and say hi over the weekend and we can have a chat and you can tempt me with goodies LOL
Have a safe trip
When I get some cash I intend to talk to you about going all FBO ignition so that should prove I both support you and I approve of the product.
At the mo the Runner is at 12 in and 37 total, I may lose or gain a few degrees if I get some track time as I have had no time at all to do anything on this car as I have been building BB mopars and sb mustang motors almost non stop!
I will pop over and say hi over the weekend and we can have a chat and you can tempt me with goodies LOL
Have a safe trip
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Anonymous