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8 & 10 cyl Bristol cars Type 407 onwards - restoration, repair, maintenance etc

Holley Sniper

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  #21 (permalink)  
Old 30-01-23, 03:32 PM
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That's brilliant Mr. Green411, I am so looking forward to hearing how it goes.
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  #22 (permalink)  
Old 30-01-23, 10:00 PM
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Thank you Mr Thor (Is 'Mr' a suitable title for a God of war? Discuss...)
My current problem is trying to find a 1/8 NPT temp gauge sender with the same resistence as the standard one - the ECT sensor has to go in the top of the waterpump, where the temp gauge sender used to be. The only other available wet port for the gauge sender is a1/8 npt one on the front face of the pump, just below the old 1/2 NPT port. A £10 item that's driving me nuts......
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  #23 (permalink)  
Old 30-01-23, 10:03 PM
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What’s the resistance of the standard one?
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Old 30-01-23, 10:24 PM
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So far as I can make out,
37*c = 400 ohms
40*c = 370 ohms
50*c = 250 ohms
60*c = 165
70*c = 121
75*c = 100
77*c = 91
80*c = 87
But these were done with hot air gun or hot water so not necessarily that accurate!
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  #25 (permalink)  
Old 05-02-23, 11:16 PM
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Well the job's finished.
After connecting 6 wires, connecting the hand-held terminal provided, entering the basic engine data, you key-off to save the data and create the base map for starting. Then key on, check the fuel pump runs and primes the system, and start. It cranked for 5 seconds or so....... then it fired cleanly. And with not one iota of drama it immediately settled into a steady fast idle…..Whew…………….
All I’ve got to do now is hope it was worth it.
THe Sniper self-learns the fuelling as you drive (timing is still from the distributor) so I'll report back once I've driven it a bit.
There'll be an article about it in a future Bodacious, I hope.
Thanks for your interest. And patience!
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  #26 (permalink)  
Old 05-02-23, 11:32 PM
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The self learning sounds fun...do you teach it what foot to the floor means first or save that part of its education until later?
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  #27 (permalink)  
Old 06-02-23, 12:30 AM
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Encouraging progress! Do you have plans to add the Hyperspark distributor so that the Sniper can control ignition timing?
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  #28 (permalink)  
Old 06-02-23, 12:04 PM
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Back to other ways of improving fuel consumption - A bit of research suggests that the 383 is internally balanced so it should be fairly straightforward to adapt to a 46RH transmission with an adapter plate and spacer for the flex plate. PATC amongst others have them readily available, but at about $800.
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Old 21-02-23, 06:41 PM
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Default Update - Woe, woe and thrice woe

Well..........

Haven't driven on the roads yet as there's not been enough rain in my area (west of Cambridge) to wash all the winter salt off the roads. So I've fired 'er up a few times and run up to temperature, mainly because it felt good and I'm still getting used to my lovely old 411 actually starting when asked to, instead of doing the automotive equivalent of saying 'Shan't' and stanping it's pretty little foot....

I noticed that tuel gauge wouldn't register so I took the sender out to check the float for a puncture and test the resistence as the float arm moved. All was ok, although there's no reading at the very bottom of the float arm's travel. In the end all I had to do was clean the sender's earth terminal and off on it's travels went the gauge needle, into the heady reaches of roughly half full.

The old 383 was happily idling away after 3rd start when it just coughed and cut out...aah....

Fuel pump wouldn't run with ignition on but ran normally when earthed. Pink ignition wire and red & black main battery connections all had power. Main Sniper fuse was intact. The HHT couldn't find the ECU when connected so the conclusion was (ie my Responsible Automotive Adult Julian said that) the ECU was dead.
I rang Holley Tech and they gave me some tests to do, all of which I'd just done under Julian's eagle eye. So Holley Tech agreed with Julian that as it was all connected correctly, power was available, then the ECU had failed. As it was less than 90 days since purchase it was down to the vendor (Summit) to replace it.
I've emailed Summit and they asked for quotes to send the unit back, which I've provided, and they're thinking about whether they want it back or not.

Anyway, at least my Anglo-saxon copulative vocabulary has had some excercise even if my 411 hasn't...
Will update further when something happens.
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  #30 (permalink)  
Old 23-02-23, 01:37 PM
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Thanks for the update - sorry to hear you've product issues.
Giving stuff back to the States is a real pain when it doesn't work or is not as described - hope it's sorted soon.
Great that when it was working it was idling happily.....looking forward to the next instalment.
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  #31 (permalink)  
Old 27-05-23, 09:34 AM
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Excellent article in the latest Bodacious with plenty of useful info for those of us considering following suit.

Very keen to get an update on driveability and any improvement in performance and fuel consumption.

I do hope someone tries out the Hyperspark distributor. It seems to me to be just as important to get the spark at the right time as to get the fuel mixture bang on.
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  #32 (permalink)  
Old 27-05-23, 11:25 AM
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Superb article in BODAcious, thank you. Like other people, I'm thinking of going down the EFI route for my S2 412 360.
Sorry to hear of initial gremlins, ain't that just how it goes.

A question - why did you go for the Holley Sniper? If I go onto the Summit Racing website and filter by Chrysler small block LA, then the option which comes up is the Edelbrock pro-flow.
It is a bit more expensive, but then Bristols have always been a car shaped receptacle for money.

Anyone any experience or thoughts?
Thanks
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  #33 (permalink)  
Old 28-05-23, 12:40 PM
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Thank you for the compliments!
I eventually got the replacement Sniper from Summit. I say eventually because I wanted an audit trail amd thus I initially emailed them. This produced lots of waiting 2 days for them to reply, which consisted of promises but little action. So I rang them and was polite and friendly but firm, whereupon stuff started happening. I kept the pressure up with daily phone calls for a few days until I got an email from their carrier confirming collection. A week or so later the package arrived safe and sound. I had to pester them to refund my £58 UPS fee for returning the dead one though. I don't think Summit were trying to avoid sending the replacement or paying the credit, but I do think that their processes could do with a bit of tighteneing up when dealing with foreign buyers who need a free replacement item. But at least they ship overseas, unlike Holley. So yes I would buy from Summit again. Since then I've discovered that I could have bought a Sniper from CM Frost of Wellingborough, Northants, who are a long standing US parts supplier. Probably more expensive, but less hassle.They keep reasonable Mopar stocks too, as they seem to supply the Jensen club.
So the replacement is fitted and I've since driven about 400 miles. Driveability is excellent, as is starting either cold or hot. Key on, wait a cople of seconds while the fuel pump primes, crank and away it goes. The first tankful gave 14 mpg, including learning, a lot of idling and many shortish journeys while I learned to trust it. The carb gave 12-14mpg and of course was subject to all the usual carb problems, including a strong smell of fuel all the time (I could find no leaks though).
I chose a Holley Sniper because it was simple-ish to fit and as it's a throttle body (ie like a 4-barrel carb but with injectors at the bottom of the barrels) with integral IACV, MAP sensor and TPS then I could disguise it. My understanding of an Edelbrock Pro-Flo is that it's a port injection system. So it's more modern and efficient, but is also more complex and couldn't be disguised. I've used Edelbrock stuff on my old V8 Ford Popular hot rod and it was very good, so I've no doubt the Pro-Flow would work as well as, or better than, the Sniper.
I'm in two minds about a fullyelectronic distributor, which the Sniper ECU could control. I know the old mech/vac advance curve works on my car, and as you'll know I've got rid of the points. Timing curves for 383s are around the internet, which could be copied and loaded into the Sniper, but the question is which one to use? So I'll probably run it as is for a year or so and see how it goes.
I'm currently checking the car over for the trip to the Le Mans Classic at the end of June. The radiator had a pinhole leak so I got it checked over and fixed (5 other pinholes found under pressure test, so it's a good job I did) by Anglia Radiators of Cambridge. They do lots of classic cars and warbird repairs for IWM at Duxford, are a proper old-fashioned place and I can recommend them. Of course one of the trans fluid cooler lines was seized so I've replaced that with Kunifer.
It'll be interesting to see what happens to the fuel 'economy' on the Le Mans trip! Will report back as & when.
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  #34 (permalink)  
Old 28-05-23, 04:49 PM
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Thank you Mr Green411 for sharing your experiences with the Holly setup.

I am currently on the return leg of a trip to Italy in my 411 S4, It is not directly comparable to yours - with the later series 400ci engine + torqueflite. It also has a 603 rear axle with longer top-gear ratio, and MSD ignition kit both fitted by Martin Barnes several years ago. I bought an Edelbrock ‘Performer’ 750cfm from Summit to replace the worn out Thermoquad with electronic choke. This worked pretty well immediately out of the box, and fits with the original air-cleaner. I took it for a rolling-road tune up but no adjustments were required. Almost certainly over-carbed, but seems to suit it well, with easy starting and good kick-down when needed.

I had not bothered to check fuel consumption up until now, fearing the worst. However having covered 1700 miles on this trip so far, my back-of-fag-packet calculations tell me it is returning just over 16mpg. This is using regular 95 fuel and sometimes 98 super when conveniently available. Whilst It is still undoubtedly a very thirsty machine, it is slightly better than I was expecting. Seems happiest on long motorway runs between 2500-3000rpm where it averages 17-19mpg. On days with more stop/start and mountain driving it returns 12-13mpg.

I have occasionally flirted with the idea of fitting an LPG conversion, but based on other forum comments the downsides appear to outweigh the upsides, unless the car is used for everyday substantial mileages, so have rejected that idea.
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  #35 (permalink)  
Old 01-06-23, 01:48 PM
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Dezelsky, thank you for thanking me!
Much respect for driving your car such a long way - had any problems? I'm not a fan of LPG conversions myself, although I'm not sure why. Maybe too complicated thus too many opportunies for a failure to proceed? (on the assumption that a Bristol would never do anything so vulgar as to break down....)
As soon as I have any proper empirical-ish fuel consumption results (yes, good or bad!) I'll let y'all know. But so far I can say that starting, idling stability, part throttle driveability and general crispness are much better.
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  #36 (permalink)  
Old 11-06-23, 03:14 PM
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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.
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  #37 (permalink)  
Old 05-07-23, 01:40 PM
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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.
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  #38 (permalink)  
Old 05-07-23, 04:09 PM
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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
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  #39 (permalink)  
Old 05-07-23, 07:04 PM
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Great to hear all well. Thank you for taking the time to share.
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  #40 (permalink)  
Old 19-09-23, 07:49 PM
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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.
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