Getting to the finish line on this refresh here. Started with the stock distributor and Holley Brawler. We've been fiddling with timing and adjustments, idling with AC on and off etc. Idling with the AC on has been a pain in the butt. My friend wants the carb for one of his projects and I thought it might be a good time to simplify and move up to a Holley Sniper. Was looking at this Sniper and their distributor which I think requires this. Then thought that it might be more practical to go with this MSD (MSD Ready to Run 8529) and the Sniper instead. Less parts and a limiter. Also sounds like the Sniper would work nice if I decide to go with an aluminum radiator and electric fans down the road.

Any thoughts on the Sniper, their distributor or the MSD. I'd like to do all this at once and I've got the budget to get it done. Just not sure what all I need, compatibility with the MSD and just overall opinions on the move to this set up.

 

What do you use the car for? How many miles a year will you put on it?

 

Get the Holley distributor. It is good for the EFI to control timing, not just have a set advance curve.

 

1. Hauling *** around town and turning my wife on. 2. Maybe a few thousand miles a year. I'd be shocked if I put more than 5k a year on it. Its definitely not going to sit in the garage.

 

Me personally, I like the simplicity of a carb and a normal distributor.

 

So I've been up and running for a few weeks and still haven't been able to get it all dialed in to where I'm happy. Tuning is really out of my wheel house and I'm turning to my friend to help me out. Was essentially hoping that EFI would take some of that fiddling off the table.

 

It may... but it also introduces a whole new set of problems and failure points.

 

Can you elaborate? I don't mind chasing failure points and upgrading replacing a handful of things "while I'm down there". I'd like to get to a point where I've worked through this enough that it becomes a relatively solid and dependable vehicle. I'm sure they'll be issues down the road but I'd like to stay ahead of the curve if I can.

 

Hopefully you understand the delta between a closed-loop EFI system and an open-loop EFI system; if not, ensure you understand the delta. I'm not going to speak for Eric (oldcutlass) but introduction of an EFI system into a vehicle which was not designed to operate under either a closed-loop EFI or open-loop EFI introduces additional failure points which did not exist under standard OEM builds for these engines. Certainly not stating they aren't beneficial or even a worthwhile investment, just ensure you understand both systems w/ regard to stoichiometric (lambda) ratios.

 

My perspective is that with a simple carb and traditional distributor you can tune an engine to be very efficient and reliable so that generally will not leave you stranded requiring a tow. When you introduce modern electronics, the failure points increase and the ability to repair easily suddenly becomes extremely complicated. The other issue is the cost vs benefits, outside of bragging rights, to me the performance benefits are not great enough for me to convert. Maybe I'm just old fashioned.

 

Hate to dash your hope chief. I understand some things but have zero knowledge in this area. I understand that it’s a popular upgrade or at least it comes across as one from the few I’ve seen at car shows etc.

Im good at taking things apart and just beginning to learn how to put things together.

If it’s a situation where I’d be biting off more than I can chew I have a really nice shop a quarter mile down the road that services my company vehicles. I’m sure they’d do the job for me. They do service vintage vehicles regularly.

Im just looking to make steps in the right direction. My current set up seems to consist of a lot of tuning and fiddling.

Maybe my expectation of this being an upgrade or “set it and forget it” or something close to that are misguided and misinformed.

 

That's good feedback. Read up on the "operation" of a closed-loop EFI and an open-loop EFI. Modern cars, motorcycles, boats etc. which are developed for and employ EFI systems are nearly 99% closed-loop EFI systems which operate under the auspices of a Body Control Module (BCM) Programmable Control Module (PCM) and any additional "CM" you'd like to entertain. Each "system" feeds into the entire system for clean & efficient operation(s) of the EFI as a "system". Most of the upgrade EFI systems to classic vehicles are of the open-loop variety - there is essentially no "feedback" occurring by any system. These open-loop EFI systems require input tuning (some constantly). Read up on them & become acquainted. Here's a decent (short) write-up on EFI system operations. It's for motorcycles but the operation(s) remain the same. The primary reason I understand these systems is because I own a closed-loop EFI motorcycle.

EDIT: With the URL this time.

Open Loop vs Closed Loop: Understanding Fuel Injection and Tuning

 

I’m a computer guy, but I really like my quadrajets. They’re simple, mechanical and unlikely to leave you by the side of the road.

It used to be most any mechanic knew what to do with carburetors, but I have the impression those guys are aging out of the repair system and the next generation doesn’t have much training on arcane devices from the last century like quadrajets. That was a plus for carbs, but maybe not so much anymore.

For a small block Olds be aware that Cadillac used the Olds 350 in the Seville in the early 80’s, I believe you might be able to find a multiport GM intake manifold from one of those cars. But modern intake designs are probably better.

I keep an eye on the fuel injection space and can’t quite bring myself to throw the switch. I know I can get a well rebuilt qjet from SMI for about $500-600. Throttle body FI looks like its the best part of $2,000 and multi-port higher than that - maybe $3,000 by the time you’re done with manifold, fuel pump, return line, computer, and injectors. Either system will need some tuning once it’s on the car. It’s your choice whether you’re changing cheap jets, rods & springs or fuel injection map files. I look at throttle body injection as an in-between solution and it’s not that attractive to me.

I’ve put many weeks over 35 years tuning, tweaking, rebuilding & learning about qjets. Certainly more than $3,000 worth of time and parts. But I enjoyed learning about these systems. It takes time to learn how to get the choke right. It takes time to figure out how to rebuild them, it takes time to tune cruise and WOT. All of this makes FI more attractive assuming you’ve got the $ and time is at a premium.

The middle ground for me has been adding 02 sensors on each exhaust pipe to see what qjet-provided AFR/Lambda values are doing in each driving situation - idle, cruise, WOT. But adding them assumes you know what to do when AFR or lambda is different from optimal. Much easier to play with software & probably less time consuming.

I may still switch to multi port someday, but I don’t expect mileage or performance to change much since I my AFR/Lambda values are close to optimal now. It’d be more for the experience of learning the digital way as compared to the analog way.

Fuel injection or electric is the way of the future, but I like how these cars represent a proud analog past. So I mostly stick with what GM did in those days.

Still, when you compare the precision of multi port fuel injection to a carb, the latter was well described a “putting a gasoline soaked rag over your intake manifold” with respect to relative precision. More funny than accurate, but funny to me anyway. As long as the AFR is right in a given driving situation, as far as I can tell, engines don’t much care whether they’re injected or correctly carbureted.

 

I assume the Holley has both open and closed loop? The biggest issue using a factory system, like a sbc swirl port 350 TBI on an Olds 350 was the open loop parameters. In closed loop it ran not bad with the timing advanced 10 degrees minimum, 20 was more ideal. The colder it got, the worse it ran in open loop. The GM TBI was set up for a peanut cam motor, even the 204/214 cam was pushing it. These systems are designed to run on mild to pretty wild motors, so no doubt some tuning will be required.

 

You don't have a clue dude. ALL I REPEAT ALL of the aftermarket TBI and multiport systems use a wideband FEEDBACK system, in other words CLOSED LOOP. How else would the system know how to change the VE without that feedback? And by the way what is Stoich on todays fuel?
OP- did you use a wideband to tune your carb? If not then I understand your trouble and frustration. That Brawler is a good carb that can be tuned to run very well.
So if you want to do it right then buy a wideband. Then decide if you want to change your entire fuel system and go EFI.

Man the internet is full of bad info....

 

How is the OP going to use a wideband to tune his Holley Brawler carburetor? Are you saying the Holley Brawler is a TBI carburetor, if so then I'm mistaken. I wasn't aware the OP had ANY oxygen sensor installed in his vehicle. How would you tune any TBI without an oxygen sensor installed? I'll take your word for it there are no narrow-band TBI systems and they're all wideband TBI systems today. I wasn't attempting to provide misinformation, the OP was inquiring w/ regards to whether he should even consider an upgrade to EFI. I was merely making the suggestion to get informed with regards to understanding open-loop versus closed-loop & how they relate to stoichiometric lambda.

 

I'm asking you nicely to never post on an EFI thread ever again. Thank you.
I've attached a pic of the fuel curve of a Quick Fuel/Brawler type carb on a dyno and what can be done with a quality wideband and tuning expertise. Look how flat the fuel curve is after the power valve opens etc.
All aftermarket EFI systems use a wideband. OEM systems use a narrow band because most of their life is at or near Stoich. When the pedal is pushed to WOT the O2 shuts off and it goes to a predetermeined fuel Map.
Please don't post on this subject anymore.

 

DO NOT tell me when and where I can and I cannot post. Lose your abrasive attitude.

 

Just for the record I don’t know what a wideband is. I’m bottom of the barrel stupid on all this. I mostly rely on friends that help me out here and there and instructions I dig up online.

My buddy is old school and tunes by ear and feel. We’re winging it. We did get pretty far on this though. It does run good but I know it could run better, especially since it struggles to idle if I get stuck at a light with the AC on.

My motivation for an EFI was that I’d hopefully not have to wing it so much. At the very least I could take it to a shop to set it up and I wouldn’t have to fiddle with it as much.

Maybe EFI isn’t really better than if someone properly set up my Brawler. Just kinda thought since I got the money to upgrade I should do it... provided that it is in fact an upgrade.

 

I hope someone gives you the same level of advice/knowledge you just gave and it’s costs you money and/or time. Maybe then you’ll understand. Have a nice day.

 

Buy and learn how to use a wideband. You’ll be glad you did, I promise..

 

Okay I’ll bite. Link me to what I should buy. Does it come with instructions?

Ill try it before I pull the trigger on the Sniper.

Can’t hurt.

 

I recommend the AEM 30-0300 I believe. They’re the best and fastest on the market.

 

looks like I would need to weld in a bung for the sensor.

Im going to pass on doing that.

 

Mark, aren't the newest factory cars wideband? I can definitely see the advantage of the wide vs narrow band O2.

 

You'll have to do the same if your going efi.

 

They do offer a clamp on version. You will need a bung for the Sniper as well. I will probably get my Daughter's Boyfriend to weld it in for me or I will have to do a few practice passes before it gets welded.

 

I agree that the AEM wideband 30-0300 is probably the most reliable and accurate for the money.

Not to be rude here, but you are having problems tuning a carburetor and mechanical distributor even with your buddy's help, I would recommend figuring out the carb first before you really step into a bunch of problems with EFI.

Do you know for sure that your timing mark correctly shows Top Dead Center on the compression stroke on cylinder 1? Sometimes balancers are wrong or the timing pointer is incorrectly matched to the balancer, and sometimes balancer rings slip and move, causing an incorrect timing adjustment. Did you degree the cam or just line up the dots on the timing chain?

Do you know for sure that you don't have a vacuum leak around the base of the carburetor where it meets the intake? Have you tested that there are no leaks at the edge of the intake at the top of the ports? Are you having an oil burning smoke from the exhaust? This could be an indicator that the intake ports are leaking and sucking oil out of the engine and is also a bad source of a vacuum leak.

Have you invested in a dial back (advance) timing light to check your timing curve instead of a regular timing light?
Do you know what your total advance is and at what RPM you reach total advance?
What is your advance at idle?

Do you have a vacuum advance can on the distributor and is it hooked up to ported or unported vacuum source (ported vacuum-above the throttle blades only gives you vacuum to your distributor once the throttle is opened)? Unported vacuum is hooked directly to a manifold vacuum source where when the engine is running, there is always vacuum going to the source, like where you hook up your vacuum diaphragm for the booster on your brakes. Do you know how many degrees of timing the vacuum advance can is adding?

It may be too many degrees being added, and and not pulling the additional advance out quick enough when you go full throttle.

I have used units like this one before with good success:
https://www.holley.com/products/igni...ts/parts/31035

You may be getting a dip and stumble or a lack of power if your advance weights on your distributor are sticking or not able to get you to full mechanical advance that your engine needs. This is very possible. I would aim for between 33-36 degrees of total advance.

As for keeping it running smoothly when the AC turns on, use one of these :https://www.holley.com/products/fuel...ge/parts/46-74



Let us know where you are at from these questions, and we can better direct you forward.

Being rich or lean won't make a huge difference if you are in the ballpark on the tune, between an air fuel ratio of 12.0 and 13.5 on the wideband meter. Engines are actually pretty forgiving when at full power whether rich or lean if you aren't running a super high compression ratio on the edge of detonation. The timing and the distributor are likely where your problems are to be found.

In tuning, there is a lot more power in correct timing and a good timing curve than there is with the exact correct air fuel ratio on a naturally aspirated engine with no power adders.

 

If you look most O2’s have less than 4 wires. That means they’ll be a narrow band in most cases.
Todays cars run at or near stoich throughout much of the rpm range. They don’t need a wideband for that reason. A narrow band reads from 14-15:1, stoich is 14.1:1 on today’s E10. Flex fuel cars may have a wideband but their range is still limited based on the amount of ethanol detected in the fuel.

 

Yeah, I was reading that 4 wire or less means narrow band. Supposedly Honda first used a wideband system in the 90's and it confused the hell out of technician's. I only worked on one Honda from that era and was probably only on certain models. Of course the claim on the Net is more control for emissions is why wideband is now being used by OEM. But manufacturers are cheap and it makes sense for most conditions they want lean which a narrow O2 will cover and have preset parameters to dump enough fuel to not melt Catalytic converters on full throttle runs. Is it true, wideband O2's run twice as hot as the narrow band O2? I am going to take a look at my 17 Challenger tonight and see what it has for an O2.

 

Totally agree with getting and installing a O2 wideband. Use it for tuning my 950hp. Takes out a lot of the trial and error on carb tuning. Well worth the investment . I'm using the Innovate DLG-1