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Fuel injection


1956322
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5 hours ago, Dennis Hagen said:

Have been considering EFI for my 51 Super. Would like any info on system you used. Thanks

 

 Dennis, I have a unit from AFI [ Affordable Fuel Injection.com }  from MI. They essentially used a 1990 Chevy PU unit, modified to fit. Came with EVERYTHING needed. They even made the adaptor for the throttle body to intake manifold.

 

  They have improved on the one I have, using a newer ECM [ computer ] that can mount under the hood. Mine has to be inside.

 

  12V a must. Even that will make you happy. Don't let the naysayers get to you.  

 

  PM me if you want. I am happy to help.  Will talk to you if you share your phone number.

 

  Ben

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Holley has really stepped up their game and the Sniper unit now comes in the square bore flange, 2 barrel and spread bore flange. And they now have a dual quad setup. They are arguably the best unit on the market if you can look past the $1000 buy in. I've been following these TBI systems for a while. You need a digital distributor and an alternator at the bare minimum. No one has made an in tank fuel pump plug and play kit for the gas tanks that came in 50s GM cars, either, so you either need to get one of those custom adjustable pump kits and use your own sender as a level gauge and return line/vent only, or modify your original pickup to attach a fuel pump and return line to. I've heard the exterior fuel pumps do not work well for cars that are driven if they are above the tank or exposed to heat under the hood. If you can find the Edelbrock sump system, you just bolt it to your inner fender and use your stock mechanical fuel pump. All you need then is a return line back to the tank.

 

I really want to get on this train, but I have had a lot of things happen in sequence for me that has kept me from enjoying the benefits of the 21st century.

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3 hours ago, Beemon said:

Holley has really stepped up their game and the Sniper unit now comes in the square bore flange, 2 barrel and spread bore flange. And they now have a dual quad setup. They are arguably the best unit on the market if you can look past the $1000 buy in. I've been following these TBI systems for a while. You need a digital distributor and an alternator at the bare minimum. No one has made an in tank fuel pump plug and play kit for the gas tanks that came in 50s GM cars, either, so you either need to get one of those custom adjustable pump kits and use your own sender as a level gauge and return line/vent only, or modify your original pickup to attach a fuel pump and return line to. I've heard the exterior fuel pumps do not work well for cars that are driven if they are above the tank or exposed to heat under the hood. If you can find the Edelbrock sump system, you just bolt it to your inner fender and use your stock mechanical fuel pump. All you need then is a return line back to the tank.

 

I really want to get on this train, but I have had a lot of things happen in sequence for me that has kept me from enjoying the benefits of the 21st century.

 

 Ben, I believe tanks,Inc  have an intank pump.     On the other hand, the pump I have is mounted along the frame just in front of the rear wheel. Going strong after 15,000 miles and six years.   

 

  My understanding of FiTech's fuel management system that mounts under the hood and is fed with the original pump is it needs no return line.

 

  Ben

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8 hours ago, 1956322 said:

Acutely Holley does make a plug and play tank for mid 50s chevies

 

Mid 50s Chevy is different from Pontiac, Olds and Buick. Their gas tanks, like Cadillac, have the filler in the tail light assembly. The kit that Holley sells also has two different senders. One is a level gauge and the other is the pump. So you would still need to modify your gas tank.

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It's not gonna be any better than a perfectly tuned carburetor in a climate controlled environment. That being said, if you can find a way to keep a carburetor perfectly tuned for every dynamic environment change, I'd like to know. 

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Check First Born's chronicles of his highway fuel economy improvements.  In theory, a TBI is just a fancy electronic carburetor, which makes any improvements in the areas of fuel atomization, not specifically better performance due to a possibly higher cfm flow through the unit at WOT (for the 2bbl TBIs).  The GM TBI for the '87 5.0 and 5.7L V-8 pickups was 1.56" throttle bores, but the one for the 454s was 1.69"  But they used their "normal" 3-bolt hold-down rather than a more normal 4-bolt hold down.

 

I suspect that the 454 unit would flow close to 475cfm, as the same size throttle bores on a Holley 2300 2-bbl carb was 500cfm.  The smaller unit might be closer to 375, which might well be equal to or a bit better (in air flow) than the earlier 4bbl units of the '50s.

 

So, it's more about more efficient use of fuel due to better atomization (which also impacts general drivability) than massive increases in power.

 

Seems like Electromotive was the first one to offer a universal in-tank fuel pump module?  Had to hole-saw the top of the tank to install it, as I recall.  That was several years ago.  Now, Holley has many OEM-style in-tank units for many vehicles, to their credit.

 

Enjoy!'

NTX5467

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14 hours ago, Beemon said:

It's not gonna be any better than a perfectly tuned carburetor in a climate controlled environment. That being said, if you can find a way to keep a carburetor perfectly tuned for every dynamic environment change, I'd like to know. 

 

So  would the engineers!   

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The word I got form Tom Toal, GM carburetor engineer, "Carburetors and not engineering, they are art." And you can bet your stoichiometric algorithm on that.

 

According to Tom the only way they got FI to work well was to throw out most of the variables they could measure.

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Where most of the "power" will come from is throttle response improvements and better atomization.  Nothing which might show up on a chassis dyno, but something you feel.  Which can make the engine feel more  energetic so less throttle might be needed for a given result.

 

On a carb, the air flow increases first, then that pulls fuel out of the float bowl (past all of the fuel path restrictions and other calibration areas) into the venture.  So in some cases, you open the throttle and WAIT for the engine to respond.  On EFI, as soon as the throttle position sensor notes ANY throttle movement, the system instantaneously responds with more or less fuel.  So things just feel better.  Hence, the feeling of "more power", when it's really just better throttle response.  And, once you re-learn your driving to not waste that additional response from a given throttle movement, you might end up using a bit less throttle input for a given result and also enjoy a possible fuel mpg increase.

 

Where the fuel economy can increase is when you take throttle out of the motor, as in coasting.  The fuel is usually trimmed back to "idle" and can result (on the "Instant MPG" displays on newer vehicles) of 99mpg while coasting.    Additionally, accelerating briskly, so you get to your cruising speed sooner, can help overall mpg.  The more time you spend in the lower gears just consumes more fuel, unlike accelerating slower (with a carb) to keep it out of the "fuel enrichment" mode, as we were told to do back then.

  

Still, even $1K for the basic kit (with install kits adding to that amount!), kind of hard to justify the added cost of the parts AND labor to install them just on suspected fuel savings alone.  Your judgment call.  Having a car that's more enjoyable to drive should be worth something, just don't expect "the moon".

 

Every so often, I run across somebody who had one of the name brand self-learning TBI kits installed on their car.  For one reason or another (in some cases, still unknown!), the advertised benefits never happen.  MPG stays in the single digits (in one case, on a Buick 430) and everything that's tried just doesn't seem to work.  I know that initial calibration data is important, but the self-learn function just doesn't seem to do its job.  Not sure why.  Some have said it's due to the intake manifold design (single plane vs dual plane), but I don't know why that would really matter if it doesn't t matter to a carb.

 

The newer units seem to have adopted the "returnless" fuel system the OEMs have used.  No return line needed as the pump's operation is modulated to keep the engine supplied with adequate fuel.  OR the pressure regulator is on the fuel pump module rather than on the EFI unit.

 

I've been waiting for Holley to cull their EFI products a bit.  They seem to have acquired many of their competitors over the past 5 years, so some will certainly "go", I suspect.

 

Enjoy!

NTX5467

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As far as I can tell they all still need a return line.. The only one that didn't was the fi tech one but that was kinda bs to.. It said you didn't need to run a return line if you were running their fuel command unit with it.. So I download the fuel commander instructions and the fuel commander unit needs to run a return line lol.

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Only the MSD unit has a built in PWM fuel pump controller. You would think because MSD is owned by Holley, they would have access to the PWM controller technology. That however is not the case. You could instead run a system like an OEM car and have the pressure regulator in the tank with the fuel pump, but you would then need to calculate the fuel line head loss and then deal with the fuel injector pulse reverberation. 

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On 4/24/2019 at 4:04 PM, 1956322 said:

I had forgotten about the msd set up cause they don't offer a 2 bbl version.. But now that I'll be going 4bbl guess that doesn't matter

 

Remember that the 4bbl EFI TBI units have a max air flow capacity of 1000cfm initially, but many are now closer to 650cfm.  Those earlier 1Kcfm models were what turned me off to them, back when Holley had a 2bbl system that was "analog" unless you got the upgrade module and O2 sensor kit.  Seems like they claimed it was good for 300 horsepower?

 

PWM fuel pump control should be something that is now more generic than otherwise, I would suspect.  Not sure how Holley is keeping everything separate in their multiple lines of EFI systems!  ONE thing might be if the 4bbl throttle plates are staged (primary and secondary) or if they all open at once?  The other question would be if their new QJet replacement TBI works better at lower rpm, in relation to fuel atmomization and such, than the normal 650cfm 4bbl unit?

 

NTX5467

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Willis, as I understand it all four throttle plates open at the same time. I know at least on the Holley sniper, it has a dip in lag setting to simulate the secondaries opening, kind of like a near lean bog as the engine vacuum pulls open the rear barrels. Kind of a neat nostalgic feeling, similar to Aurora Design's solid state radio conversion that has the simulated tube warm up period. 

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  • 1 month later...

Don't mean to hijack the thread but I was doing a search for Tom Toal. Does anyone know if he is still working on quadrajets. I sent a carbb out to be restored and it came back looking nice but not working well at all. Was told Tom was the one to go to get it running right. If he is still working could I have his contact info ? thanks

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I've been away from the forum for a while since I moved. otherwise I'd have seen this sooner and replied. I put a Holley Sniper on my 61. It has a setting that you can use for your original non-digital distributor. I got it installed and started but I have not driven it around the streets yet. I ended up moving right in the middle of the install and and have no place to work on it until I build a new shop. It does run though and I can drive it around that yard but want to tune it up a little first. I also swapped out the dynaflow for a 4L60E.. For the purists, I can put it all back to original very easy.  FYI, they also make a progressive linkage for the secondaries and also a different throttle linkage for use with a throttle rod instead of a cable. Using the older throttle rod setup the stock linkage made the throttle very touchy. The new one changed the leverage so it's not touchy anymore.

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Thanks for that update!  I think the throttle linkage on the new QJet replacement EFI is also progressive, but I'll have to verify that.  When you pull the engine oil dipstick, does the oil smell normal or with strong hydrocarbon smell?  Just curious.  What interface with the torque tube was used with the 4L60E?

 

Thanks,

NTX5467

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  • 2 weeks later...
On 6/17/2019 at 7:39 PM, NTX5467 said:

Thanks for that update!  I think the throttle linkage on the new QJet replacement EFI is also progressive, but I'll have to verify that.  When you pull the engine oil dipstick, does the oil smell normal or with strong hydrocarbon smell?  Just curious.  What interface with the torque tube was used with the 4L60E?

 

Thanks,

NTX5467

No gas smell in the oil. '61 was the first year for open driveline. No torque tube. 😁

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