What Miles per Gallon Do You Expect on the RBRR

[RobPearce]

1 hour ago, Horace said:

We did a shade under 36mpg in our Gt6 mk2

Before this year, my best economy on an RBRR was my GT6 Mk3 in 1994 at 36MPG

[Roger Keys]

On 04/10/2021 at 21:48, PeteStupps said:

Blimey! Where was that??

Blythe Services was our worst, charging £1.59 a litre for E10 low octane

First services after we joined the M74

[SaffronGary]

After looking through the receipts and working it out it looks as though the pi returned 31.6 mpg. I know a lot of the run was cruising as the weather in places dictated that high speed stuff was out. I have never actually had reason before now to work out the fuel consumption but I guess this is ok?  

[RobPearce]

13 minutes ago, SaffronGary said:

I guess this is ok?

I'd say anything over 30 from a PI is doing quite well. Mine only gave 26 on the 2010 run.

[McJim]

I worked out that we got an average of 39.76 miles per gallon in a 1500 Spitfire, which is much better than the 35 mpg I was expecting.

All in, we did 2,768 miles from door to door.

We used 65.63 gallons (nearly all super unleaded) at a cost of £468.14 with an average cost of £1.56.5 a litre.

And worth every damned penny purely for the experience.

Jim.

[Slimboyfat]

My first couple of RBRR's were done with John Kipping in his Herald 1500 'Turn Left For Tangier' replica I built for him. On our first outing the car was still fresh out of restoration, and we were still tinkering with its induction. Initially it was twin HS4's, but JK was obsessed with fuel economy, and we quickly realised after a couple of rolling road sessions that they weren't cutting the mustard. Just prior to the event we fitted a pair of 150 Strombergs for there more refined control. These proved better, and I recall high 30's mpg overall.

With the benefit of a couple of years twiddling, and our epic East African adventure we went into our second RBRR with our ultimate set up of a single HS6 on a bored out Dolomite 1500 inlet manifold. The rest of the engine consisted of Pony 1500 lightweight crank, Spitfire MKIII profile cam, tubular manifold into Vitesse MKII exhaust. In that form JK recorded the economy figures of each section as being never less than 40mpg, but usually in the mid 40's, and on a couple of sections (when he was driving!) in the low 50's mpg.

Scroll forward a few decades, and James, and myself have yet to work up the courage to tot up the mpg of our Kastner engined  Weber equipped GT6. I would be happy if it was North of 20 mpg, but I fear it will prove to be less.

However the girls in the Courier (similar spec to JK's Herald other than it has 2.5 bore, and stroke, and therefore 1660 cc) were surprised when we kept darting into fuel stations, and they were still showing a nearly full tank. In fact I have been driving the Courier all week on its left over RBRR fuel, and it looks like I might get at least another week out of it.  

Picture of JK's Herald at Lands End on our first RBRR. You can tell how long ago it was by the fact it's in black, and white, and taken on a box browny camera.

   

[Tim Hunt]

The easing of the fuel supply situation enabled me to top up the TR's tank yesterday for the first time since Ashburton and work out a true overall consumption for the event of 36.38mpg, the best I have ever achieved. 

Tim

[thescrapman]

A light right foot this time round, knowing it's could have been the most expensive ever?

[RobPearce]

11 hours ago, thescrapman said:

A light right foot this time round, knowing it's could have been the most expensive ever?

I wasn't conscious of easing off. Indeed there were stretches where I (or my brother) drove quite enthusiastically. There was, however, somewhat less traffic than in some recent years, and I wonder whether the consequent lack of stop-start, slow moving, or need for aggressive overtaking may have contributed to some of the very good figures we've seen reported.

[ferny]

Cheapest ever 2-man RBRR for me!

Final price was £355 in fuel.

[RobPearce]

1 hour ago, ferny said:

Final price was £355 in fuel

£211 for me, including brimming it before the start and again after the end. I don't know how much my brother added to that but probably similar.

[Rubce]

In my Stag, we achieved an average of 30.6mpg overall, with between 32 and 33mpg on the motorway sections. I am happy with that as we also had lots of "smiles per mile thrown in"😄. We managed to find E5 every time we tanked up for fuel.

Bruce

[Tim Hunt]

 

On 14/10/2021 at 22:14, thescrapman said:

A light right foot this time round, knowing it's could have been the most expensive ever?

Yes Colin, in view of possible fuel availability issues Mike and I treated the event as an econonmy run this time. We could see little point in arriving at controls before they opened and spent most time on motorways and dual carriageways between 2,500 and 2,800rpm in o/d top. However, we had some fun on roads in the Highlands and Wales and were not averse to using the car's full performance when appropriate for overtakes. The absence of hold ups helped economy as well, I have no mechanical fan on the 4A, the temperature gauge barely reached half way and the Kenlowe did not cut in once during the whole run. I forgot to partially blank off the radiator before leaving home, if the enbgine had been running hotter I might have achieved even better econonmy.

Tim

[MK Joe]

We done the C2C but didn't check the economy but on our 1st RBRR we averaged 35.4mpg in a 1500 Spitfire with no overdrive.

My mate drove the car carefully and I was pushing it, so may have got a little bit more driving conservatively. 

I changed the jets on my SU's before the RBRR and got the carbs balanced professionally.  I think this helped the most.

[PeteStupps]

Resurrecting this thread for the fuel-economy anoraks among us.

Be interesting to know what mileage others recorded on the run. Team 101 took the A9 'diversion' south through Scotland for fear of being washed away down the A82 through Glencoe. 

Odometer says total RBRR mileage was 1920 miles, but tracking my route on Google Maps tells me it was 2119 miles. 

Either way I'm very happy with fuel economy, which is either 40.6 or 44.5 mpg.

Which seems a bit ridiculous when we were cruising a 70 on motorway sections wherever possible, and hooning around the country lanes otherwise. 

[Tim Bancroft]

After setting a 5000rpm limit, we got 28mpg in my TR6.

351L at a cost of £620.00, average fuel cost being £1.77/L.

Thought it would cost £600.00.....

[Mike North]

Team Moby 'made progress' wherever possible, some of you will have seen us. Brimmed just before Knebworth and afterwards, we got 25.68mpg. The B.Beacons cost us with a low of 22 whilst the steady transit stages saw highs of 28/29. To be honest, and considering the state of tune, we're quite happy with that but spent more than Tim 🤣

[Jos]

Team Arnie (car 137) managed 26.25mpg for the whole run. 327.57 litres at a cost of £572.60. We had a GPS Tripmeter which showed 1892 miles. Not bad for a 3.9l V8 and more than I would normally get (23.81mpg). Worth every penny for a superb event.

[PeteStupps]

4 minutes ago, Jos said:

 We had a GPS Tripmeter which showed 1892 miles.

Nice one Jos, which route did you take through Scotland on Saturday?

[Stuart Wilson]

Haven't worked out mpg but put in approx 250 litres. Not sure how much is left, tricky to tell with no fuel gauge. 

Yes that's right no working fuel gauge. 

Wetherby fuel price was absolutely ridiculous. We knew that before and had planned to fill else where. We went 20miles north and filled at Conygarth truck stop near Leeming and it was about 35p per litre cheaper!!!

[yorkshire_spam]

Does anyone have a list of the prices for e5 super/premium at the places they stopped? I forgot to take note - so working out MPG is a bit tricky!

 

[Jos]

We took the A82 down past Loch Ness (no fallen tree - we took the opinion that a tree doesn't take long to cut up) and then we were going to take the A85. Just after getting onto the A85 some nice young people told us that the road was flooded to knee height and the TR7 V8 wouldn't get through. We therefore went back onto the A82 past Loch Lomond and then set the satnav for Gartcosh to get us across Glasgow - worked a treat.

[yorkshire_spam]

Filled in the prices I was missing from the internet, gives us about 36mpg. Seems high, need to check if I missed something. 

[cook1e]

On previous RBRRs in my GT6 I always consistently achieved just over 33 MPG. This time I achieved just under 35 MPG. I have changed the diff since last time from the standard GT6 overdrive 3.89 ratio to a Spitfire 1500 3.63 ratio, this obviously decreases revs when high speed cruising which has probably resulted in the improved fuel consumption, before the diff change at 70mpg measured accuratly on a sat nav it was doing 3500 RPM, now at 70 it's doing only about 3100 RPM.

 

The speedo packed up after 408 miles so we were using the satnav and a GPS speedo, but I worked out the mileage from Google Maps, we did make a couple of wrong turns and also took a different route from Falls of Shin to Gartosh so did a few extra miles, I calculated the mileage we covered from Google Maps and we did 1999 miles on the run using just under £450 of fuel, all but one stop was E5 Super.

 

Edited October 12, 2023 by cook1e

[Shynsy]

2 hours ago, Jos said:

Team Arnie (car 137) managed 26.25mpg for the whole run. 327.57 litres at a cost of £572.60. We had a GPS Tripmeter which showed 1892 miles. Not bad for a 3.9l V8 and more than I would normally get (23.81mpg). Worth every penny for a superb event.

We did pretty much the same as you with our 3.9l V8 in our stag.