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Holley Sniper fuel injection

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Old 02-04-2017, 09:41 PM   #1
PistolGrip
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Default Holley Sniper fuel injection

I've had my pretty-much original '62 Corvette since 1967. Both of us are now considered 'survivors'. It is a 4 speed 250 horsepower 327 with headers & a slightly bigger cam than original. It has the Carter WCFB carb. It runs fine EXCEPT, the carb seems to stumble now & then & the idle seems to slow down to a near (and sometimes actual) stall - especially in hotter weather. I had the WCFB rebuilt a few years ago, but it was still never 100% right.
A friend recently put a Holley fuel injection set-up on his car (not a Corvette), but it seems to run really nice - expensive...but nice.
My questions are...any suggestions as to solving my problem with what I have now (the WCFB)?
Has anyone used this Holley Sniper set-up on their C1 Corvette? How is hood clearance? Did you need to change much? I'd like to keep my originality as much as possible, in case I'd ever want to return it to pure original. How is your performance? Is there any other brand of fuel injection anyone uses that I should check out?

Thanks!
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Old 02-04-2017, 11:39 PM   #2
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Old 02-05-2017, 06:49 AM   #3
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Try 1/4" phenolic spacer under the carb before you launch off into some dicey technology with lots of pitfalls and a black hole for money:

http://dashman.net/search.html?q=wcfb&submit=Search

Get the right one for your carb (probably the one with the 'ears' and not the squarish one) -- confirm that...
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Old 02-05-2017, 07:07 AM   #4
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Go to this website and read the posts on the Terminator/Stealth & Sniper section.
http://forums.holley.com/
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Old 02-05-2017, 08:30 AM   #5
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Have you ever had your Carter carb rebuilt? . . . if no, that could solve your problem. I sent me Holley to the only guy that our JohnZ recommends - and my car now runs GREAT!

http://vintagemusclecarparts.com/

Tom

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Old 02-05-2017, 08:45 AM   #6
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There is really only one rebuilder. Ok, maybe more but most of us use Daytona Parts Company.





The basic rebuild is $295 (at least in my case). If you need parts then it's obviously extra. I needed the entire choke assembly.

Give them a call. They turned my WCFB around in about a week.

Richard Newton
The '58 Interior Project
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Old 02-05-2017, 09:01 AM   #7
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Quote:
Originally Posted by PistolGrip View Post
I've had my pretty-much original '62 Corvette since 1967. Both of us are now considered 'survivors'. It is a 4 speed 250 horsepower 327 with headers & a slightly bigger cam than original. It has the Carter WCFB carb. It runs fine EXCEPT, the carb seems to stumble now & then & the idle seems to slow down to a near (and sometimes actual) stall - especially in hotter weather. I had the WCFB rebuilt a few years ago, but it was still never 100% right.
A friend recently put a Holley fuel injection set-up on his car (not a Corvette), but it seems to run really nice - expensive...but nice.
My questions are...any suggestions as to solving my problem with what I have now (the WCFB)?
Has anyone used this Holley Sniper set-up on their C1 Corvette? How is hood clearance? Did you need to change much? I'd like to keep my originality as much as possible, in case I'd ever want to return it to pure original. How is your performance? Is there any other brand of fuel injection anyone uses that I should check out?

Thanks!
C1 originality and the aftermarket fuel injection are mutually exclusive. Do your homework...

Spend the $295 for a WCFB rebuild and the $35 for the spacer kit and use the $3,000 you save for a road trip (or two)..
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Old 02-05-2017, 09:10 AM   #8
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Here's an entire thread on Daytona Parts Co. and the WCFB.

The big problem with the aftermarket EFI kits is that after a few years the company goes out of business and no one knows how to calibrate or fix them. You get to spend another $3,000+.

Richard Newton

Last edited by rfn026; 02-05-2017 at 09:15 AM.
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Old 02-05-2017, 09:59 AM   #9
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Quote:
Originally Posted by rfn026 View Post
Here's an entire thread on Daytona Parts Co. and the WCFB.

The big problem with the aftermarket EFI kits is that after a few years the company goes out of business and no one knows how to calibrate or fix them. You get to spend another $3,000+.

Richard Newton
yep, Accel is still in business, but their Thruster EFI is an orphan...

Bill
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Old 02-05-2017, 10:01 AM   #10
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Well - its a little more seductive than just 'dust in the wind' companies....many of the videos will lead you to believe the things are plug and play... Get the 'electronic carburetor' bolt it on and life is good.

When in reality you usually need a fuel tank return line for proper operation of the electric fuel pump, which you also have to add; then, on some cars, to avoid cavitation if the fuel pump is tank mounted (which many kits recommend for cooling) it may require a custom tank (e.g. 67 Chevelles) and then to get the most benefit you will want the system's "brain" to control the spark map...requiring more dodads and sensors.

You can drop about $4,500 on one of the systems without straining too hard..

And when all is said and done you still have the problematic centralized carburetor-style fuel distribution configuration, not the optimized fuel injector 'rail' configuration of modern cars.

Then we should discuss the cr@ppy tech support when things hiccough - (search old threads)...

Last edited by Frankie the Fink; 02-05-2017 at 10:06 AM.
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Old 02-05-2017, 11:11 AM   #11
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Quote:
Originally Posted by PistolGrip View Post
It is a 4 speed 250 horsepower 327 with headers & a slightly bigger cam than original. It has the Carter WCFB carb. It runs fine EXCEPT, the carb seems to stumble now & then & the idle seems to slow down to a near (and sometimes actual) stall - especially in hotter weather. I had the WCFB rebuilt a few years ago, but it was still never 100% right.

Thanks!
The problem may be as simple as the OE 201 15 VAC not passing the Two-Inch Rule, due to the higher overlap cam.

Measure manifold vacuum at idle speed. Determine the number stamped on the VAC bracket and the start and stop points. Then apply the Two-Inch Rule Rule to determine whether a 15", 12", or 8" VAC is required to pass.

If you don't understand THE RULE, search for a post started by me, download and read my tuning seminar. If the lazy OE centrifugal curve is still there quickening it will improve performance and fuel economy.

Duike
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Old 02-05-2017, 11:17 AM   #12
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Or simply a worn accelerator pump leather cup, or, vapor lock (occurs on my '63 WCFB even with a fresh Lars-rebuilt distributor, tweaked on a SUN machine with a new vac advance)...on hot days. I'd bet dollars to doughnuts its the latter...or possibly both...
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Old 02-05-2017, 04:05 PM   #13
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Quote:
Originally Posted by SWCDuke View Post
The problem may be as simple as the OE 201 15 VAC not passing the Two-Inch Rule, due to the higher overlap cam.

Measure manifold vacuum at idle speed. Determine the number stamped on the VAC bracket and the start and stop points. Then apply the Two-Inch Rule Rule to determine whether a 15", 12", or 8" VAC is required to pass.

If you don't understand THE RULE, search for a post started by me, download and read my tuning seminar. If the lazy OE centrifugal curve is still there quickening it will improve performance and fuel economy.

Duike
duke, how do I search for your seminar?...
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Old 02-05-2017, 05:05 PM   #14
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duke, how do I search for your seminar?...
good luck with that....

Bill
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Old 02-05-2017, 05:18 PM   #15
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Quote:
Originally Posted by wmf62 View Post
good luck with that....

Bill
I take it you have tried also bill?...
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Old 02-05-2017, 05:34 PM   #16
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Quote:
Originally Posted by 20round View Post
I take it you have tried also bill?...
here's one of his posts that references the 2" rule

"One always has to be careful that the centrifugal has NOT started at the normal speed used for checking initial timing, and also, it's best, but not absolutely necessary if centrifugal does not start until above idle speed. For most OEM spring sets this is the case.

You can either drop the idle speed until the engine barely runs to check initial or tie up the centrifugal temporarily with a rubber band.

Using a dial back light it's very easy to characterize the centrifugal curve. Bring the speed down to the point where you are certain that the centrifugal is not deployed, then slowly raise the speed until is just starts. This is your start point: 0 @ xxxxRPM. Raise the engine speed until the timing no longer advances, this is your maximum centrifugal advance, and on some engines the speed may have to be raised to as much as 5000 RPM, but if your dist. has been modified with light springs the the centrifugal might start as low as 500 and be all in by 2500.

Once you have a start and end point, you can also check some values at one or two points in between.

The sum of initial plus centrifugal should add up to 34-38 degrees on a SB.

You should also characterize the vacuum can. You can do this with a Mighty Vac type vacuum pump, or just use oral vacuum and a vacuum gage. Disconnect the vacuum can from manifold vacuum and rig up your vacuum pump or a gage and hose to apply oral vacuum. Apply vacuum until the timing mark starts to advance. This is your start point, 0@xx". Now increase vacuum until the timing mark stops advancing. This is your maximum vacuum advacne xx@xx". Compare the vacuum for max advance to your normal idel vacuum.
The vacuum can should reach full advance AT LEAST two inches BELOW what the engine normally idles at.

Now connect the vacuum can to manifold vacuum, and set the idle to your normal idle speed. This is TOTAL IDLE timing, which should be the sum of initial plus full vacuum. If you have a quick centrifugal curve, you might also have a few degrees of centrifugal. You want the total idle timing to be in the range of 20-25 degrees for medium performance engines and 25-30 for SHP engines.

Now you have characterized the timing map for your engine, and you can work from here to make any corrections such as swapping the vacuum can to one that is more suitable for your engine, or modifying the centrifugal curve. As a rule, better low end torque will be achieved the quicker the centrifugal curve, and the limiting factor is usually low rev detonation with too quick a curve.

To give you a idea of your finished data set, here are the final numbers I came up with after retuning the fuel and ignition maps on my Cosworth Vega after I reindexed the cams to different than OEM timing.

Normal hot idle speed/vacuum: 900 @ 18"
Initial timing: 14
Centrifugal: 0@1000, 9@ 1500, 18@2000
Vacuum: 0@4", 11@8"

Total WOT timing = 32
Total Idle timing = 25

Duke
"


Bill

Last edited by wmf62; 02-05-2017 at 05:37 PM.
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Old 02-05-2017, 08:19 PM   #17
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Quote:
Originally Posted by wmf62 View Post
yep, Accel is still in business, but their Thruster EFI is an orphan...

Bill
Quote:
Originally Posted by rfn026 View Post

The big problem with the aftermarket EFI kits is that after a few years the company goes out of business and no one knows how to calibrate or fix them. You get to spend another $3,000+.

Richard Newton
Accel is part of Holley now, niether one is going anywhere any time soon.
The complete Sniper kit including fuel system is $1250.00 not $3000.00.
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Old 02-05-2017, 08:38 PM   #18
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I guess it depends on how you define 'complete'...with a stock ignition coil/points you won't get timing control with the Sniper; break out your wallet for a complete MSD setup if you want that...

The Sniper QuickStart Manual states that Holley STRONGLY recommends an in tank fuel pump....oh yeah - that's gonna cost you too.

As I said - the hype is seductive....

I've done my homework when I considered an EFI setup....other should do
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Old 02-05-2017, 10:00 PM   #19
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Quote:
Originally Posted by 20round View Post
duke, how do I search for your seminar?...
...ever used the Search function? It's easy...click the link near the top of the page... then "advanced search"... then chose threads STARTED by (type in) SWCDuke... there aren't that many, and you may find others interesting reading.

Duke

Last edited by SWCDuke; 02-05-2017 at 10:11 PM.
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Old 02-05-2017, 10:21 PM   #20
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Quote:
Originally Posted by Frankie the Fink View Post
I guess it depends on how you define 'complete'...with a stock ignition coil/points you won't get timing control with the Sniper; break out your wallet for a complete MSD setup if you want that...

The Sniper QuickStart Manual states that Holley STRONGLY recommends an in tank fuel pump....oh yeah - that's gonna cost you too.

As I said - the hype is seductive....

I've done my homework when I considered an EFI setup....other should do
I define complete as everything you need to get it running, yes you can add all the options you want but they are not needed to get the system up and running good. I've been running the Holley HP EFI for years on a 600hp Big Block with an external pump and never had a problem. Like I said you can add all the options you want but they are not mandatory.
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