Engine and transmission choice help
07-26-2016, 09:11 PM
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Engine and transmission choice help Hello everyone,
I have a 1970 El Camino that I am working on. I would like some expert opinions on possible LS engine/trans choices I should consider.
I am not looking to modify the engine to gain massive HP or torque gains. I will be using this vehicle as a daily driver and my main purpose of going to a newer LS motor is to gain maximum fuel economy, not looking to race it or anything like that, mid to high 300's in HP and torque should be more than adequate I believe. I am looking to get mid to late 20's in MPG, is this a realistic goal with an LS swap into the aforementioned vehicle?
Should I only consider motors with VVT and AFM technology which I guess will put me in the GEN IV category is that correct? As for transmissions I understand that both the 4L60e and 4L80e will fit my vehicle without any mods to the tunnel if the right mounts are used, is this also the case with the 6 speed Auto transmissions or will they require some cutting and or reshaping of the tunnel?
Thank you for any insight you provide in helping me plan out my future moves.
I have a 1970 El Camino that I am working on. I would like some expert opinions on possible LS engine/trans choices I should consider.
I am not looking to modify the engine to gain massive HP or torque gains. I will be using this vehicle as a daily driver and my main purpose of going to a newer LS motor is to gain maximum fuel economy, not looking to race it or anything like that, mid to high 300's in HP and torque should be more than adequate I believe. I am looking to get mid to late 20's in MPG, is this a realistic goal with an LS swap into the aforementioned vehicle?
Should I only consider motors with VVT and AFM technology which I guess will put me in the GEN IV category is that correct? As for transmissions I understand that both the 4L60e and 4L80e will fit my vehicle without any mods to the tunnel if the right mounts are used, is this also the case with the 6 speed Auto transmissions or will they require some cutting and or reshaping of the tunnel?
Thank you for any insight you provide in helping me plan out my future moves.
07-27-2016, 08:53 AM
#2
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Where are you located? My prices can't be beaten on swaps.
For things like VVT/AFM, you need to consider the downsides, and how they are controlled. Similar problems with the transmissions. An example, you might have trouble controlling a 6L80e with a gen 3 computer. Or you might have issues with the AFM as its a major weak-point. The lifters are very sensitive to oil pressure/changes and commonly fail if not taken care of.
A 6L80e/Aluminum 5.3 with AFM would be excellent for fuel economy, but you could easily get a Gen 3 iron 5.3/4L60e combo for a quarter of the price (or less) and only sacrifice 10-15% fuel economy.
For things like VVT/AFM, you need to consider the downsides, and how they are controlled. Similar problems with the transmissions. An example, you might have trouble controlling a 6L80e with a gen 3 computer. Or you might have issues with the AFM as its a major weak-point. The lifters are very sensitive to oil pressure/changes and commonly fail if not taken care of.
A 6L80e/Aluminum 5.3 with AFM would be excellent for fuel economy, but you could easily get a Gen 3 iron 5.3/4L60e combo for a quarter of the price (or less) and only sacrifice 10-15% fuel economy.
07-28-2016, 09:29 PM
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Where are you located? My prices can't be beaten on swaps.
For things like VVT/AFM, you need to consider the downsides, and how they are controlled. Similar problems with the transmissions. An example, you might have trouble controlling a 6L80e with a gen 3 computer. Or you might have issues with the AFM as its a major weak-point. The lifters are very sensitive to oil pressure/changes and commonly fail if not taken care of.
A 6L80e/Aluminum 5.3 with AFM would be excellent for fuel economy, but you could easily get a Gen 3 iron 5.3/4L60e combo for a quarter of the price (or less) and only sacrifice 10-15% fuel economy.
For things like VVT/AFM, you need to consider the downsides, and how they are controlled. Similar problems with the transmissions. An example, you might have trouble controlling a 6L80e with a gen 3 computer. Or you might have issues with the AFM as its a major weak-point. The lifters are very sensitive to oil pressure/changes and commonly fail if not taken care of.
A 6L80e/Aluminum 5.3 with AFM would be excellent for fuel economy, but you could easily get a Gen 3 iron 5.3/4L60e combo for a quarter of the price (or less) and only sacrifice 10-15% fuel economy.
Thank you for the reply. I am in SoCal. So a Gen 3 computer will or may have trouble controlling a 6l80/6l90. Have you ever installed a six speed in a 1968-1972 A-body? Does it fit, or do you have to modify the tunnel a great deal to get it in there?
If I opt for the 4 speed is it wiser to invest in the 4l80e/4l85e over the 4l60e for greater reliability or not really necessary if keeping the hp under say 450?
I am on the budget side as I need to do other things to the car beyond drive train. If I opt for Gen 3 I don't see a huge difference between the pricing of the 6.0L over the 5.3's. Will there be much gain stock to stock between the two?
07-29-2016, 10:03 AM
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A gen 3 computer by itself will not control a 6L80e. The trans controller is inside of the valve body on the 6L80e and will only communicate with a 58x/4x ECU from a Gen 4. There are options around this, but they're not cheap. All you're really gaining with a 6L80e is a REALLY short 1st gear and a 2nd overdrive, and a bunch of extra weight.
A 4L60e is going to be a lot less weight and hassle, but it does have a few weak points. A 4L80e is a good bit heavier, but far more durable. I'm running a 150k mile non-rebuilt stock 4L80e with a couple of minor valve body mods in my 850 HP Nova and it doesn't skip a beat. Either can be controlled with a Gen 3 computer no problem.
You must be in the only part of the country where a 6.0 isn't much more expensive than a 5.3. Here a full pullout 5.3 is 400-600, a 6.0 is 1200-1400.
A 4L60e is going to be a lot less weight and hassle, but it does have a few weak points. A 4L80e is a good bit heavier, but far more durable. I'm running a 150k mile non-rebuilt stock 4L80e with a couple of minor valve body mods in my 850 HP Nova and it doesn't skip a beat. Either can be controlled with a Gen 3 computer no problem.
You must be in the only part of the country where a 6.0 isn't much more expensive than a 5.3. Here a full pullout 5.3 is 400-600, a 6.0 is 1200-1400.
08-04-2016, 05:54 PM
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Your mileage goals are a bit high I think. I'm thinking low to mid 20s. With E10 gas in a Yukon XL with the AC on with 6 people the best I squeezed out was 17 mixed driving. Half of the road time was 65-70 and the other half was 30 and less probably. My dad had a 2000 extended cab long bed 1500 with a 5.3L and it got around 22 when he got it with 150,000. In 3/4 ton trucks a 6.0L might get 14 mpg but that's in a heavier and taller truck with heavier drivetrains. If memory serves me right I got the church van with a 6.0L and 6 speed get 16 or 18.