Holley Sniper

[dezelsky]

Just under 3000 miles for the trip in total. No problems, and no oil or coolant top-ups required. Comfortable and fast enough to keep up with anything modern on the autoroutes - a real Grand Tourer as it was originally intended, I guess. The total fuel cost is painful, so best not to think too hard about it.

[Green411]

Hi all
Got back from the Le Mans Classic on Monday, and after an 872 mile round trip at last I've got some empirical fuel consumption results.
When I drove my new car home from the dealers last September it was about 170 miles of mostly 60-80mph (indicated, officer....) on dual carriageway plus some stop-start crawling and took almost a full tank of E5, working out to 13.6mpg. At the current UK E5 average price of £1.59/L (RAC) that's 53p per mile.
The car just didn't have the performance one would expect, it smelled of fuel and it was a very reluctant starter, hot or cold.
The car now has Pertronix electronic ignition and, of course, a Holley Sniper with an ethanol-proof fuel system. As I've said in recent posts it now runs very well, starts quickly hot or cold, has a rock steady idle and rpm's cleanly with no hesitation or fluffing aparrent. The plugs are the right tan colour instead of being caked in soot.
After fitting but before the Le Mans trip it did 14mpg on E10, which at the current UK average of £1.45/L (RAC) that's 47p per mile = 6p per mile reduction.
On the Le Mans trip the car started full, used 3.5 tanks and so had half a tank left when I got home. Filling it up to get back to where I started brought the total fuel used to 250.5L/55.2 gallons. Thus the overall fuel consumption for the 872 mile trip was 15.8mpg, on E10 = 42p per mile at current UK average.
The detail by tankful is:
1st tank 14.2mpg (lots of crawling on UK M11, M25 & Eurotunnel plus 70-80mph on autoroute Calais-Abbeville)
2nd tank 15.8mpg (almost entirely 70-80 mph/3-3500rpm on autoroute to Le Mans with slow stop/go drive through Rouen)
3rd tank 16.7mpg (as above)
4th tank 17 mpg (50 miles of 70-80mph on autoroute, queues at Calais Eurotunnel, 100 miles of 60-70mph in UK plus 5 miles of crawling at Dartford crossing).
So in round figures I've spent c.£2000 to save roughly 10p per mile, which is a 20k mile payback or roughly 7 years. However, and it's a big however, the improvements in overall driveabilty are such that even if there was no improvement whatsoever in 'economy' (if that's the right word....) other than the move from E5 to E10, I'd do it all again. I accept that a more refined aftermarket system - Edelbrock's Pro-Flow, for example - would probably yield more efficiency, but the entry cost is higher. And a new carb would be cheaper, better than the old carb but not as good as a throttle-body efi like the Sniper. EFI = rifle, carb = shotgun. So ya pays ya money and takes ya choice.
And I haven't even thought about refining the target fuel/air ratios in the Sniper's ECU map yet........
Thanks for your interest in my little adventure.

[dwomby]

Thanks for the detailed results.

I think, given our lower US full prices and my low annual mileage, the investment is not worth it to me. I will keep tinkering with the carb and Pertronix ignition once I get the car back on the road.

David

[David C]

Great to hear all well. Thank you for taking the time to share.

[David C]

I have just spotted that Holley have released the Sniper 2 EFI kit. Hopefully this deals with most of the issues they had with the original. Really tempted now but will wait for a few home user reports.

[Green411]

It will be interesting to see how much of a real improvement the Sniper 2 offers. Do let us know if you get one, and what it's like. Although my first one failed (dead ECU after an hour or so's total running time from first start) I get no interference issues with my Sniper, for instance, and the basic connections are genuinely easy to follow. Possibly the major new thing is easier connection to their electronic distributor?
I haven't got to that bit on mine yet - am still using the stock distributor albeit with Pertronix kit installed. I haven't even mapped the advance curve yet.....hmm.....perhaps I should stop typing, put my laptop away and get my timing light out..........

[David C]

I think you definitely should!

I'm not sure about the 411, but the Poly engine in the early V8s has the distributor at the rear of the block so I don't think interference would be a big issue. Ford engines with the distributor right next to the ECU seemed to be the worst offenders.

The big issue for me was the number of reports of failed ECU on the original Sniper. I very much hope version 2 is more rugged. V2 also supposedly has improved throttle geometry.

The main reason I am considering a Sniper is that fitting overdrive brings the engine speed so low at motorway cruising speeds that a standard distributor doesn't have the timing range to cope. Also the Weiand inlet manifold that I have presents mixture issues at low RPM that are hard to accommodate with a standard carb and distributor. These are both marginal issues but adding a Holley Hyperspark controlled by the Sniper should bring everything into line. Add a decent tubular manifold with ceramic coating and I very much hope to have an original engine and nearly original transmission with the drivability and economy of much more recent cars.