Octane Boosters for Cerbie RR
Discussion
When I get my new Cerbie 4.5RR I plan to use Miller's Octane Booster with super unleaded to ensure octane is right up there to get maximum torgue and power.
Would you guys recommend this approach ?
With my previous car, Lotus GT3, it made a noticeable difference, I'm hoping it would with the Cerbie, especially with the 95/97 button set to 97.
I also heard the Shell Optimax is the best to use, since it gives somewhere in the region of 98 and a bit octane. Has anybody experienced using Optimax?
Cheers,
GerryB
Would you guys recommend this approach ?
With my previous car, Lotus GT3, it made a noticeable difference, I'm hoping it would with the Cerbie, especially with the 95/97 button set to 97.
I also heard the Shell Optimax is the best to use, since it gives somewhere in the region of 98 and a bit octane. Has anybody experienced using Optimax?
Cheers,
GerryB
Been using optimax for 3000 miles now and it is definitely the DB's. Much better top end over 6000 rpm, no pinking at all when flooring the throttle at 1500 rpm in 5th gear and I even seem to be getting better consumption. On a previous thread on optimax I passed on details of optimax given to me by a buddy who is a petrochemist at Shell. It is supposed to be 98.6 octane minimum and typically is delivered at the pump at between 98.9 and 99.1. Why bother with octane booster??
Regards
john
Regards
john
quote:
I guess if that is the octane rating of Shell Optimax, there is no reason to use octane boosters, but I'd still have it for emergencies in case I can't get hold of a shell station or super unleaded.
In emergencies why can't you just press the button and switch to the 95 octane map from the 97 one?
danny
quote:
Been using optimax for 3000 miles now and it is definitely the DB's. Much better top end over 6000 rpm, no pinking at all when flooring the throttle at 1500 rpm in 5th gear and I even seem to be getting better consumption. On a previous thread on optimax I passed on details of optimax given to me by a buddy who is a petrochemist at Shell. It is supposed to be 98.6 octane minimum and typically is delivered at the pump at between 98.9 and 99.1. Why bother with octane booster??
The Cerbera has no knock sensor, so no benefit to be gained from higher octane... as for power, unless you can change the fuelling/ignition for it, you won't get any extra power either. Bike magazine recently did a test with and without Optimax, and got exactly the same power - spoke to Shell, and they agreed it won't help power without the engine modifying it's ignition, but that it still had better detergents.
danny
And the RR conversion is just a button for retarding timing to take advantage of octane but with the engine tuned to take advantage of this. I assume that there might be different cams or someting else to actually get more power?!? Anyone know what is actually different mechanically?
The Cerbera has no knock sensor, so no benefit to be gained from higher octane... as for power, unless you can change the fuelling/ignition for it, you won't get any extra power either. Bike magazine recently did a test with and without Optimax, and got exactly the same power - spoke to Shell, and they agreed it won't help power without the engine modifying it's ignition, but that it still had better detergents.
I'd agree that early ECU did not compensate for variations in fuel octane, but I thought later versions did. I guess one way to prove this is just to try it out. Of course for me, I'd have to wait a few more weeks.
Gerry
The AJP does not have a knock sensor in the latest versions either, so there is STILL no way it can take advantage of different octane fuels!
It would be interesting to see your car on a dyno as soon as it's run in then, could then also see the difference between the 95 & 97 maps.
As for "needing" maximum power... there's not that much difference between a standard and a red rose that you could ever really *need* it
danny
It would be interesting to see your car on a dyno as soon as it's run in then, could then also see the difference between the 95 & 97 maps.
As for "needing" maximum power... there's not that much difference between a standard and a red rose that you could ever really *need* it
danny
The button changes engine mapping and so adjusts ignition for different octane levels to get the performance from the fuel, that is the whole point of it. As for not much more power, I think I read that it goes from 420 to somewhere approaching 450, I could be wrong but that seems like quite a boost to me.
quote:
The Cerbera has no knock sensor, so no benefit to be gained from higher octane...
Who said anything about knock sensors, or adaptive mapping? Who said anything about more power? The higher octane rating of optimax suppresses the 4.5's tendency to knock at low revs/wider throttle openings (which is what a higher octane rating is supposed to do) and has nothing whatsoever to do with knock sensors or adaptive ECU's. At very high revs such as over 6,000 it is beneficial to any engine, and seemingly more so for the AJP, to have a smooth flame front in the combustion chamber to ensure power delivery is optimum.
Also, I'm led to believe by my bike fanatic buddy that Bike magazine did find a small power increase of around 1.5 bhp in their test. He is using Optimax in his Ducati 916 and has found a huge improvement in the power delivery at the top end
Regards
John
I have now done some research and found it was on pistonheads review of a German Cerbera RR with a rear diffuser that they said "His latest ride is a March 2001 Red Rose spec 4.5 Cerbera. This has 20-30bhp more power than a standard 4.5 when running on 97RON fuel (a switch on the dash allows you to select the appropriate mapping for the fuel in use)" so the fuel does make a large difference.
With regards to Optimax, I switched to it from normal 95 RON unleaded in the Chim and it seems to make a HUGE difference. The car seems more comfortable throughout its entire rev range.
After doing this, tried it in 'er indoors Duke, the Mini and 'er indoors FZR400 winter run around and they all seem to be more comfortable, the Mini seems to be running properly for the first time in ages!
I cant tell you what this is attributable to mind, I just know the results! Lets face it, any TVR is quite fast enough for everyday use!
Matt.
After doing this, tried it in 'er indoors Duke, the Mini and 'er indoors FZR400 winter run around and they all seem to be more comfortable, the Mini seems to be running properly for the first time in ages!
I cant tell you what this is attributable to mind, I just know the results! Lets face it, any TVR is quite fast enough for everyday use!
Matt.
quote:I said it won't make a difference to the power without a knock sensor. Of course it does on the RR Cerbera's with the selectable octane maps!
I have now done some research and found it was on pistonheads review of a German Cerbera RR with a rear diffuser that they said "His latest ride is a March 2001 Red Rose spec 4.5 Cerbera. This has 20-30bhp more power than a standard 4.5 when running on 97RON fuel (a switch on the dash allows you to select the appropriate mapping for the fuel in use)" so the fuel does make a large difference.
quote:The 20-30 bhp is official in the same way that the 420bhp is official...
I have now done some research and found it was on pistonheads review of a German Cerbera RR with a rear diffuser that they said "His latest ride is a March 2001 Red Rose spec 4.5 Cerbera. This has 20-30bhp more power than a standard 4.5 when running on 97RON fuel (a switch on the dash allows you to select the appropriate mapping for the fuel in use)" so the fuel does make a large difference.
My point was that the fuel won't make a difference unless the engine can take advantage of it, e.g. a knock sensor or a switch on the dash to select different maps! These engines can clearly take advantage of it, but the standard non-red rose ajp don't have the above. John McKenzie's point's about low revs/wide throttle and high revs smoothness notwithstanding (makes sense to me).
quote:
Also, I'm led to believe by my bike fanatic buddy that Bike magazine did find a small power increase of around 1.5 bhp in their test. He is using Optimax in his Ducati 916 and has found a huge improvement in the power delivery at the top end
All these things are subjective- i.e. running better at the top end - it's hardly scientific. Refer to the latest issue of Bike magazine yourself, page 162 I think. There was no change in power measurable whatsoever on a four cyl bike - can't remember which one. Can you get your mate to find the quote?
danny
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