I’m just teasing... no harm was meant.
CK5
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To run a Carb or not?
- Thread starter TJ1978
- Start date
Looking at all the EFI systems on Summit's site is like porn for Gearhart. Lot of stuff I didn't even know existed.
Exactly it’s so confusing. I just want all of it. Hahaha.
I have a list of “needs” but I opted to do my shocks first, so I ordered from ORD today.
Will slowly work through it.
I have a list of “needs” but I opted to do my shocks first, so I ordered from ORD today.
Will slowly work through it.
"Window" shopping is always fun anyway.
not antagonize me . . . its just how will people search and find the info later who have no idea the new name some have given it . thats my point here . i sometimes have a hard time finding stuff here i know i posted and words i used . so why make it any harder is the point i was making .
Well, I suppose. But how would an average person measure that in any practical manner? Think about how many times the crank is turning at idle.
GM did this experiment with the LT1's in the 90's, when they went from batch to sequential on the same engines, without any other changes. Sequential was worth maybe 5HP. Sequential vs. batch should not be used as the determining factor when selecting a system. If that was the only difference, and the price was the same, no brainer.
I personally would be more interested in the fuel economy aspect. Not that I chase fuel economy, but having the power when I want while getting a little more economy when I'm not using the power is my thought.
I honestly hadn't really thought of any possible power increase, just the thought of it being able to meter the fuel more precisely.
Seems like with aftermarket EFI, I never seen any discussion about MPG. Just drive-ability and throttle response is all I seem to see.
I just believe that if the engine runs cleaner by better management and mixture of the fuel and air, there should be benefits in economy as well as the oil stays cleaner for a longer time. It has been proven that excess fuel and the carbon that is created by combustion can degrade the oil.
I don't see hotrod guys discussing fuel economy because it's shunned by the "power guys". But if your ride guzzles gas so fast that you can't afford to go play, what's the point of having it? So if small gains can be made in fuel consumption, it should help stretch dollars in fuel and oil, since the oil shouldn't degrade as quickly either.
But I have been accused of "overthinking things ".
The March '20 issue of Car and Driver showed the differences between the current production Mustang Shelby GT500, Camaro ZL1 and Challenger Hellcat Redeye. The 5.0 in the Mustang used slightly more fuel than the other two. Why?? And what would that mean to the bank account after a few years of driving it?
Hate to say it, but I haven't seen the economy increase I had hoped for with injection, that's for sure.
Maybe I had my Q-jet dialed in, and the 305 and 350 were both in optimum drivetrain combinations, but 17MPG is the absolute best I have ever seen with any of the combo's I've run in my K5's. And I keep my speedo correct, so there is no wonky numbers. 305/Q-jet/700R4/208/3.08/31's
350/Q-jet/465/205/3.42/31's
350/TPI/465/205/3.42/33's
350/TPI/465/241/3.42/33's
(The first two engines were stock with hydraulic flat tappets, manifolds, etc; last two were mild/factory roller cams, Vortec heads, full roller rockers, headers)
The only way injection is going to help mileage, IMO, is if the carb isn't working properly in the first place, and/or there is a way to lean the injection out at cruise (as GM attempted to do back in the day). I'm not aware of the aftermarket units being able to run "lean cruise", but if they can, then you'd see some gains. EagleMark I believe managed 19MPG with lean cruise in a Suburban. Cylinder deactivation may be a possibility as well, but I don't know what gains there are with using that, and I'm assuming that is solely the realm of LS and later systems, not aftermarket, yet.
Look at the MPG's of the trucks as technology has progressed. It *really* hasn't increased like you'd expect over time. Carb, TBI, Vortec, LS, none of them have astounding MPG gains over the predecessors, even with more aerodynamic truck designs.
Vs. a carb, I'd really argue drivability as the number one benefit to the swap. Even if you could see something like a 6MPG increase, how many miles is it going to take for you to break even for the cost of an injection system? A ton.
exactly 100%
beags86
Eastbound and Down
Bingo Dave.
It's very well documented that the EFI engines starting with the tbi era that generally the engines last longer and upon rebuild the blocks and engines are in better shape. Less ring ridge, etc. Generally speaking the oil isn't as black either. So less carbon.
Just my general opinion on mpgs is that EFI does return some mpgs, but it's not a huge difference between a properly jet carb, so over normal driving may 1-2 mpg? Maybe 1/2 a gallon. I don't know. It's a very hard measure. You would have to be to test scientifically. To know for sure. To many variables to know. Wind speed, temp, fuel quality. Etc.
But even if I got 1/2 mpg better, if I drove that vehicle over 100k that's a return.
Is it enough to pay for the upgrade? Idk? Is that the only reason for a guy to upgrade? Idk. Everyone has to make that call for themselves.
For me it's EFI, everytime. And I can't get carbs out of my life quick enough.
That said. I'll probably always have a few kicking about.
With my FAST EZ EFI I can lean out the cruise AFR on the fly. I tried it on a road trip and it actually worked. When I had a carb the best I'd get was 11mpg, with the FAST set up normally (14.0 cruise AFR for best responsiveness) I get 13mpg, and with lean cruise at 15.0 I got 15.5mpg.
LS engines in Australia have a lean cruise feature built into the ECM. It activates only under certain conditions and can move the AFR from 14.7 to up to 16.0. it does work and people who have it report around a 2mpg gain on the highway. Unfortunately It was never available in the US because of emissions. The leaner mixture produces more NOX and they came to the conclusion that it was more environmentally friendly to burn a little more gas than produce more NOX emissions. It sounds stupid that one country gets lean cruise and another doesn't... However, you can hack your US ECM to think it's in Australia by swapping in an Australian VIN and it unlocks the lean cruise features. This only works for GEN 3.
LS engines in Australia have a lean cruise feature built into the ECM. It activates only under certain conditions and can move the AFR from 14.7 to up to 16.0. it does work and people who have it report around a 2mpg gain on the highway. Unfortunately It was never available in the US because of emissions. The leaner mixture produces more NOX and they came to the conclusion that it was more environmentally friendly to burn a little more gas than produce more NOX emissions. It sounds stupid that one country gets lean cruise and another doesn't... However, you can hack your US ECM to think it's in Australia by swapping in an Australian VIN and it unlocks the lean cruise features. This only works for GEN 3.
Not to go too off topic, but what is the strategy within FAST to run lean? GM (ancient TPI stuff) had a few parameters that needed to be met to go lean cruise, which were pretty stringent and on/off even under the same conditions, because ultimately, one of the problems running lean is heat being absorbed by the piston. Outside the NOx problem of course, but GM got caught and it was never released in the US in any case, even though the code was still there for it.
The strategy is manual control with the "EZ" systems, you manually change the air/fuel ratio for the "cruise" parameter to whatever you wish to run. It will adjust fueling to run that whether your engine likes it or not.
However, it won't run that at idle or WOT, as those are separate adjustments. Also, anything between low load and WOT it will average the target A/F ratio. So at any point above low load it will be something richer than the cruise ratio depending on what your WOT ratio is set at.
This is the way many of the self tuning no laptop systems work. The Edelbrock systems are also both port injection and sequential, which are both beneficial. If you want more detailed control than that, there are many fully tunable systems available such as Holley Dominator/HP/Terminator, FAST XFI, BigStuff3, also the Australian Haltech or Brazilian Fueltech, etc.
Hard to use the LS platform as a benchmark for fuel efficiency since we don’t have a decade of carbed LS engines to compare to. They don’t seem terribly fuel efficient to me, I believe based on the torque curve
But going from a very closely tuned Qjet to FI on 3 different engines, the fuel logs I had for them were very close in terms of consumption from Qjet to TBI.
But going from a very closely tuned Qjet to FI on 3 different engines, the fuel logs I had for them were very close in terms of consumption from Qjet to TBI.
So if load stays constant (low load, flat ground, cruise control) it would theoretically remain in lean cruise as long as it was within those parameters?
I've actually got a sensor bung in my oil pan, as I've been unable to figure out how, other than oil temps (which is going to be difficult with splash oiling anyway) you'd know how much heat your pistons are seeing. And while I've been tempted to run lean cruise, its possible to go too far, and really do some damage, and I'd like to see if the oil temps will be indicative at all.
Have there been any issues you are aware of with FAST and lean cruise?
I really feel its about the only method that is somewhat practical to make "large" gains in economy on these rigs.
My mental math may be screwed up. But I'm thinking "saving" of two gallons of gas from an ok carb to an injection system on a 30 gallon tank. Roughly $6/tank. And what will any of these systems set you back? If the system was $1000, that would take ~166 tanks to break even.
I stand firm that drivability should be the number one consideration to go to injection. If lean cruise is an option, and you drive a significant number of miles under light load, economy could be second I suppose.
I've actually got a sensor bung in my oil pan, as I've been unable to figure out how, other than oil temps (which is going to be difficult with splash oiling anyway) you'd know how much heat your pistons are seeing. And while I've been tempted to run lean cruise, its possible to go too far, and really do some damage, and I'd like to see if the oil temps will be indicative at all.
Have there been any issues you are aware of with FAST and lean cruise?
I really feel its about the only method that is somewhat practical to make "large" gains in economy on these rigs.
My mental math may be screwed up. But I'm thinking "saving" of two gallons of gas from an ok carb to an injection system on a 30 gallon tank. Roughly $6/tank. And what will any of these systems set you back? If the system was $1000, that would take ~166 tanks to break even.
I stand firm that drivability should be the number one consideration to go to injection. If lean cruise is an option, and you drive a significant number of miles under light load, economy could be second I suppose.
I guess that I don't have issues with driveability as I don't put up with a crappy carburetor. I figure it out, even if I have to find help. So that is a less important factor to me. Which is why my big block shortbed will only get the Q-jet taken off for a multi point injection system, if that were to ever happen.
And just FYI, the Proflo has a separate AFR setting for cruise and can add timing advance with vacuum. I don't believe that it has enough adjustability for someone who wants to dig deeper, but it has some.
After watching what @folkenheath has found and done with his, I would seriously look at the EZ system in the future, now that I have played with this Edelbrock one a little.
@dyeager535 my perspective is from multiple angles. I have 2 trucks that I have had for over 20 years. Lots of fuel has gone through them. I have been around around semis for over 30 years. Fuel consumption is a factor there. I had a Cat 3406 that had the fuel mileage improve when we bumped it up to a 550HP from 430HP. Swapped injectors and reflash.
And I believe that you missed part of my point about that other aspects from a more efficient tune. @beags86 got it.
Doing oil samples on engines has taught me that there are things that can't be seen easily. Research and data are needed.
I wasn't trying to cause any sort of contest about chasing just MPG, if you notice, I did say economy and fuel consumption. Pounds per hour..
If you don't want to worry about that, that's cool, others may want to.
And just FYI, the Proflo has a separate AFR setting for cruise and can add timing advance with vacuum. I don't believe that it has enough adjustability for someone who wants to dig deeper, but it has some.
After watching what @folkenheath has found and done with his, I would seriously look at the EZ system in the future, now that I have played with this Edelbrock one a little.
@dyeager535 my perspective is from multiple angles. I have 2 trucks that I have had for over 20 years. Lots of fuel has gone through them. I have been around around semis for over 30 years. Fuel consumption is a factor there. I had a Cat 3406 that had the fuel mileage improve when we bumped it up to a 550HP from 430HP. Swapped injectors and reflash.
And I believe that you missed part of my point about that other aspects from a more efficient tune. @beags86 got it.
Doing oil samples on engines has taught me that there are things that can't be seen easily. Research and data are needed.
I wasn't trying to cause any sort of contest about chasing just MPG, if you notice, I did say economy and fuel consumption. Pounds per hour..
If you don't want to worry about that, that's cool, others may want to.
Great insights and I’ve learned a lot. I’m probably goin efi down the road. The ultimate decision for me is ProFlo or Holley. I hope to tackle this project this year. I need to set aside some money. I had to do the shocks first, they were horrible and my engine is fine for now....so priorities.
For my truck needs and what I’ve read coupled with cost. I’m still learning towards Holley but I have time to kick this around.
For my truck needs and what I’ve read coupled with cost. I’m still learning towards Holley but I have time to kick this around.
It depends on the rig, what I recommend is, if you are controlling an electronic trans (ie 4L60E or 4L80E), or using dry nitrous or turbos, or want full laptop control, the Holley Dominator/HP/Terminator is the way to go. If you don't need any of those things, save your money and get the Edelbrock as you'll likely be plenty happy with it.
