Sniper install {long} - with timing control

[Broncobowsher]

Bonus feature. The kickdown for the transmission didn't adapt to the new intake and the Sniper. I could have made it work but I had a different idea. I have air for an air horn. I got a little Parker pneumatic cylinder and a 3-way solenoid. Solenoid is wired into the A/C cut. Temp is dialed all the way up to 300° so I will never see that. But I can dial in at what throttle setting the A/C cuts, or in my case the piston fires and moves the kickdown linkage. Computer adjustable mechanical kickdown. Test fired in in the garage, looking forward to road testing it.

 

[kylakekevin]

Thanks for your in depth write up!

 

[LSUpete]

Which exhaust pipe did you use to install the O2 sensor?

 

[DirtDonk]

Hmm, you have true duals then? Not sure how that would work in a system that only sees 4 cylinders.
It's why most of us have gone back to either a 2-into-1 system or have tied the duals together really well.
Never seen an O2 sensor in a crossover/H/X-pipe, but I wonder if that's an option.

Otherwise you're stuck. If you have only a single O2 input with true dual exhaust, it probably does not matter which side you used.
Might call Holley (or whoever's system you're using) to see if they have a recommendation.

Paul

 

[LSUpete]

Hmm, you have true duals then? Not sure how that would work in a system that only sees 4 cylinders.
It's why most of us have gone back to either a 2-into-1 system or have tied the duals together really well.
Never seen an O2 sensor in a crossover/H/X-pipe, but I wonder if that's an option.

Otherwise you're stuck. If you have only a single O2 input with true dual exhaust, it probably does not matter which side you used.
Might call Holley (or whoever's system you're using) to see if they have a recommendation.

Paul

Paul I have the 2 into 1 system.....but the O2 sensor is supposed to be as close to the engine as possible, so I presumed that installing the O2 sensor AFTER the muffler (where the single exhaust pipe occurs) would be incorrect.

Where did you locate yours?

 

[73azbronco]

Correct should locate O2 bung right after the header flange.

 

[LSUpete]

Correct should locate O2 bung right after the header flange.

On which side?

 

[Broncobowsher]

Which exhaust pipe did you use to install the O2 sensor?

Driver's side. It just had more room for installing. And it was easier to crawl under the driver's side while parked in the garage.

With a typical dual plane intake each side of the carburetor or throttle body EFI feeds 2 cylinder on each bank. So while you are not reading 100% of the exhaust, you are getting a balanced reading. The full bore race engines or manufacturers development engines will have port by port sampling, it really isn't needed on the street.

A 2 into 1 exhaust will still make no difference. The merge is so far behind the engine it isn't a good place for the sensor. You only get one, just like all the other self learning EFI. Don't worry about getting both banks, just put it in the best spot you can whichever bank that happens to be. Close to the engine, but after all the exhaust has blended together.

The truck is down at the moment. I was not getting enough charge with the headlights and A/C on. Just did a quicky alternator rebuild but want to run by a parts store and have it tested before I put it back on. There is a chance this is a factory 40A alternator. It is the factory never replaced alternator (still has all the clips on the back of it) and reference material shows it should be 40A even though the case is stamped 60A. Not sure so it will be tested. Might end up with a 100A 3G later.

Back to good drivability. The progressive throttle linkage is a must. But with that you have to run computer controlled timing. I still have a little cold driveaway lean spot just off idle. Fine once warm. I know there are setting to dial that out, just have too many other things going on. The weather is getting nicer and I hope to drive it more.
Something else I need to check is restriction going into the fuel pump. I had one pump get noisy and die, replaced it, the other was getting noisy, replaced both pumps and they were quiet. Now one is getting noisy again. I suspect that the holley hydromat isn't keeping up with the flow of the pump. I used the smallest one they offer. The joys of doing your own mix of parts.

 

[DirtDonk]

Where did you locate yours?

Looks like Broncobowsher has the good news. Mine is factory and has two sensors each right after the manifold to exhaust junction. Basically up in, or near the area where a header flange would be.

With the aftermarket ones I've worked on the crossover from the driver's side to passenger side happened early and the tube merged in just about the right spot to catch the full flow.
But go with what was said and it sounds like you'll be in good shape.

Paul

 

[jlylec]

Thanks for this write up Broncobowsher!

I'm running an Affordable Fuel Injection TBI on the 351w in my '76. I have an HEI distributor. Knowing what you know now would you swap the HEI dizzy for one the Sniper could control timing on? I'm trying to decide if it's worth the extra work.

Also...are you running an electric fan and controlling it with the Sniper. I've been wanting to switch to an electric and see that it can control that too.

 

[Broncobowsher]

I have tried electric fans a couple of times, always went back to a mechanical fan. Broncos are hard to cool, the radiator opening is just too small. The sniper does have the ability to control cooling fans, I have seen the command to turn a fan on at operating temp.

By saying an HEI distributor, you are referring to a GM style distributor? I am fairly sure there is an easy way to lock that out so the Sniper can control the timing. I locked out and adjusted the Duraspark. The only reason to buy the Holley Hyperspark is for easier plug and play. It might make you faster since your wallet will be lighter.

From what I have experienced, The Sniper needs a progressive linkage to be drivable. The standard 4-barrel Sniper needs the timing control when you have the progressive linkage kit since you loose the vacuum advance. For me I found the vacuum advance played a big roll in the drivability at part throttle.

Overall I think it was worth it for the timing control. I am still playing with it, but there is so much tuning potential while keeping your hands clean. Once the air/fuel ratio is correct, all the tuning that is left for power and economy is left in the timing.

 

[sprdv1]

I have tried electric fans a couple of times, always went back to a mechanical fan. Broncos are hard to cool, the radiator opening is just too small.
.

that is for damn sure....

 

[sprdv1]

Paul I have the 2 into 1 system.....but the O2 sensor is supposed to be as close to the engine as possible, so I presumed that installing the O2 sensor AFTER the muffler (where the single exhaust pipe occurs) would be incorrect.

Where did you locate yours?

it can definitely just be trial / error sometimes...

 

[FordBronc]

Broncobowsher thank you for the very in depth write ups and all the follow on information. The more I read, the more I might just stick with my 2bbl MC carb. lol

I was planning on the 4150 4bbl and adding the progressive linkage right off the bat, I have now learned even more about that idea, thanks again.

Keep us posted.

 

[BPerry]

I have tried electric fans a couple of times, always went back to a mechanical fan. Broncos are hard to cool, the radiator opening is just too small. The sniper does have the ability to control cooling fans, I have seen the command to turn a fan on at operating temp.

By saying an HEI distributor, you are referring to a GM style distributor? I am fairly sure there is an easy way to lock that out so the Sniper can control the timing. I locked out and adjusted the Duraspark. The only reason to buy the Holley Hyperspark is for easier plug and play. It might make you faster since your wallet will be lighter.

From what I have experienced, The Sniper needs a progressive linkage to be drivable. The standard 4-barrel Sniper needs the timing control when you have the progressive linkage kit since you loose the vacuum advance. For me I found the vacuum advance played a big roll in the drivability at part throttle.

Overall I think it was worth it for the timing control. I am still playing with it, but there is so much tuning potential while keeping your hands clean. Once the air/fuel ratio is correct, all the tuning that is left for power and economy is left in the timing.

Starting my Sniper install this Saturday on the 351w.
Other than the previous suggestions in your thread, which was awesome btw. Would you suggest going to a cable set up for the throttle and kickdown linkage?

Running stock C4, in a previous thread you suggested I change out tranny's in lue of a gear change. That will be on the long term financial list... ha!

Thanks in advance!

BP

 

[Broncobowsher]

If you have a good mechanical linkage that isn't causing issues I would try keeping it. The Bronco didn't have a good linkage and you could feel the gas pedal bouncing as the body/engine mounts moved around on a rough road. Fixed with a cable. But even a cable isn't fool proof. My first one had a little too much angle through the firewall and the cable cut a groove in it and started sticking.

As for the kick down. Try what you like. Pneumatic piston was what fixed it on my C6. I prefer the solid on/off for the kickdown. One day I was booking it home and not all the way into the kickdown. Felt the transmission slipping in and out of kickdown. That was when I was running a rod. I was tickling the edge of the kickdown, but not at the same time. That is rough on clutches. After that I went with the true on/off of a solenoid controlled air piston. Couldn't find a pure solenoid that had the travel and force I wanted for the kickdown. But the little coil on an air valve is about the same as a relay as far as current draw on the computer is concerned. and I already had air for the air horn. Easy for me.

 

[BPerry]

If you have a good mechanical linkage that isn't causing issues I would try keeping it. The Bronco didn't have a good linkage and you could feel the gas pedal bouncing as the body/engine mounts moved around on a rough road. Fixed with a cable. But even a cable isn't fool proof. My first one had a little too much angle through the firewall and the cable cut a groove in it and started sticking.

As for the kick down. Try what you like. Pneumatic piston was what fixed it on my C6. I prefer the solid on/off for the kickdown. One day I was booking it home and not all the way into the kickdown. Felt the transmission slipping in and out of kickdown. That was when I was running a rod. I was tickling the edge of the kickdown, but not at the same time. That is rough on clutches. After that I went with the true on/off of a solenoid controlled air piston. Couldn't find a pure solenoid that had the travel and force I wanted for the kickdown. But the little coil on an air valve is about the same as a relay as far as current draw on the computer is concerned. and I already had air for the air horn. Easy for me.

Thank you sir!

I'm not having any issues with the throttle at this time. That being said, this rig sat for 15 years untouched...
Motor is running strong, no smoke, but does have a tick. Rulled out header gaskets as I just replaced them, think it's a value. So I'm pulling those off this weekend..

Timing is being a real pain, she's jumping it seems; just can't find the sweet spot. TDC is verified and carb is pulling good vacuum. Once she's warm, it's go time. Cold start, better not be in a hurry! I had already planned on the efi conversion and have the complete sniper set up laying there.

Far as the kickdown, on three different occasions while pulling a pretty good grade, it won't kickdown. Manual kickdown gets it there, that could be a number of things I'll have to look into. Linkage looks to kick in at about 65% throttle.

Thanks again my friend!

Bp