GM Commuter Motors

[CTX-SLPR]

Howdy,

We all know basically what I'm talking about here I think. Those smaller small blocks that GM put in larger cars as "economy" powerplants for those things too big for a 4.3L V6.
305 Vortec
L99 4.3L Gen II
4.8L Gen III/IV
and sorta the 5.3L Gen III/IV
Obviously the 5.3L is a bit more on the hot side so I'll leave it out for the timing being.
Getting back towards my Commuter/Econo Rod thread and my Tech Area Seville thread, what really is the best balance of power and economy out of these cheap and lesser known V8's?
The downside to the 305 Vortec is that its a 305 and I don't think they were ever terribly good at economy or power and there is vastly better stuff out now.
The L99 is hampered by the same 3.736in bore and an even shorter stroke but carries a bit more of a punch being a Gen II
The 4.8L Gen III/IV lacks the DOD functions and I really have no clue about how efficient of an engine it actually is or how previlant they are in the yards.
Finally they have an all aluminum 5.3L, or the iron one which just weighs more, and they make it with DOD and that might push it into more efficient status than the 4.8L which lacks it.

Cost wise I'd imagine the Vortec 305 is the cheapest but the L99 and the 4.8L aren't likely to be more expensive. In a 4100lb car which would you choose for your daily driver?

[BangShift McT]

Re: GM Commuter Motors

Any thought given to the L67 3800 s/c? I see you already had a Regal GS, it shouldn't be too hard to swap back to north/south layout. With the right gearing and trans, it shouldn't have too much issue moving a large car (esp. if you do some tweaks using older 3.8L stuff from the T-Type/GN)

[SpiderGearsMan]

Re: GM Commuter Motors

they started installing the 5.3 dod in 2005 envoy denalis , there may be some wrecks out there

[CTX-SLPR]

Re: GM Commuter Motors

I'm well versed in both the L67 and the Buick 3.8/4.1L V6 and mixing the two, though there is very little from a standpoint of physical hardware that is cross compatable. There even was an RWD version of the L36 NA cousin of the L67 SC motor in the US and a RWD L67 in Austrailia in the Holden's. The F-body L36 made the same rough HP as the L99 (200hp) and with the same oil pan configuration as the LS1 which is listed as the best pan to use for a Gen III/IV swap into a X/F/early K body. Trans is the same removable bell 4L60E so that would be the same with a different bell for the 60º metric V6 bell on the L36. I wonder if the torque curve on the L36 has enough bottom for a 4100lb car but then again there are lots of L99 caprices running around and while not fast I don't think they are painfully slow.

[TheSilverBuick]

Re: GM Commuter Motors

Like from the Economy Motors Thread (http://www.carjunkieforums.com/index.php?topic=2423.0) I think there is a point at which the power plant is more inefficent because it is not sufficiently big enough to efficently move the vehicle your best bet is still the 5.3L. From talking with a fair number of people with full sized chevy/gmc trucks and different engines the best mileage is pretty much still seen with the 5.3L over the 4.8L and 4.3L v-6. The V-6 depending on driver may do a 1-2mpg better than the 5.3L but sigificantly less power but typically does no better than the 5.3L. My Step-Dad has a 4.8L ('99) and a 5.3L ('03, before DOD) and they get the same mileage but the 5.3L truck probably has 1,000lbs more on it in work equipment and tools.

Everyone I know with a 305 and an O/D it doesn't pull over 22mpg on the highway and less than that around town, which is what I'm getting with a 455.

Don't know anyone with the 4.3L V-8, but can only imagine they are dogs in heavier cars.

[BangShift McT]

Re: GM Commuter Motors

Ok, lost in nomenclature. :D

To make sure I'm ok...

L99: 4.3 V6, 195 hp
L36: 3.8 V6, ?hp, N/A Regal motor, Camaro V6

I wasn't sure if the 3.8 (GN) and 3800 (GS) motor had any similarities, as far as I knew they were the same block. I'm on a steep learning curve with newer GM motors..

For the weight of the car, I'd say a 4.3, simply because similar-year 350 mods work with it. IIRC one of the mags built one and it was north of 300 hp@flywheel.

[CTX-SLPR]

Re: GM Commuter Motors

Ok, lost in nomenclature. :D

To make sure I'm ok...

L99: 4.3 V6, 195 hp
L36: 3.8 V6, ?hp, N/A Regal motor, Camaro V6

I wasn't sure if the 3.8 (GN) and 3800 (GS) motor had any similarities, as far as I knew they were the same block. I'm on a steep learning curve with newer GM motors..

For the weight of the car, I'd say a 4.3, simply because similar-year 350 mods work with it. IIRC one of the mags built one and it was north of 300 hp@flywheel.

L99 4.3L Gen II V8 SBC, its the "305" of the Gen II LT1 family. It was the base engine in Caprices, nothing else that I know of. Makes 200hp, 245lb-ft
L36 Series II 3800 V6 used in just about every GM mid to full sized FWD car from 1995-2005ish, also used from 96-2002 in the F-body. Makes 200hp, 230lb-ft

The relationship between the L36/67/26/32 3800 motors and the 3.8/4.1L Buick RWD V6's is basically the same as between a Gen I and a Gen III/IV SBC. The design is related, some of the dimentions are the same, but there isn't much you can swap without modifications.

I've never driven an L99 Caprice, I know lots of people like to get rid of them though for LT1's but I think that's mostly thats a power upgrade. I don't know if its a drivablity dog. I like the 5.3L DOD Aluminum V8 idea for its weight, economy, and advanced design. On a side not I could play with putting CTS-V stuff on it and make it look the part of a Caddy motor. I am however partial to the Buick motors and that V6 doesn't do so bad on torque but would probably be a bit overtasked on pulling the car from a stop in NA form and I'm not planning turbos.

[TheSilverBuick]

Re: GM Commuter Motors

I just remembered, a high school friend of mine has a Caprice with the 4.3 V-8, drove just like the V-6 (I drove it once about three years ago). Don't know what it got for mileage though.

[CTX-SLPR]

Re: GM Commuter Motors

EPA stuff on the L99 vs the LT1 in a Caprice.
L99
Regular Gasoline
16 City
19 Combined
24 Hwy

LT1
Regular Gasoline
15 City
18 Combined
23 Hwy

[dieselgeek]

Re: GM Commuter Motors

What about the vortec I5 or I6 engines? I don't think they have DOD though.

[CTX-SLPR]

Re: GM Commuter Motors

Mainly I've left them out due to the fun of trying to get one to fit in the front end of the vehicle I'm eyeballing (K-body RWD) and the fact that the transmission setup on the brand new (I got it with 38 miles on it) rental Trailblazer was one of the worst automatics I've ever driven. Granted I can dig into the tuning with my HPTuners VCM Suite and try to redo the shift tables but I'm somehow thinking it has something to do with the power band on the engine aswell. It was nice to drive on flat land or slow in the hills but freeways hills caused it to go downshift upshift, downshift upshift like crazy. How much does one with ECM and harness run these days?

RWD Northstars are also cool but again I'm leary on the fitment and there is 0 tuning available for them. I'm a firm believer that there is a lot of efficiency left on the table by the warranty minded factory tune.

[dieselgeek]

Re: GM Commuter Motors

A buddy of mine just picked up a Vortec I6 out of a Trailblazer, form the junkyard with 60,000 miles for $350 yesterday. Included ECM and harness, didn't include the "core" stuff though (starter, alternator, etc.).

For whatever reason, the 5.3s were DIRT cheap up until a month ago. During xmas there were 200+ 5.3's sitting at our local recyclers. $500 got you a mid-mileage one. Someone bought up ALL of them from him in one batch, now they're going for more like $800


-scott

[SpiderGearsMan]

Re: GM Commuter Motors

Mainly I've left them out due to the fun of trying to get one to fit in the front end of the vehicle I'm eyeballing (K-body RWD) and the fact that the transmission setup on the brand new (I got it with 38 miles on it) rental Trailblazer was one of the worst automatics I've ever driven. Granted I can dig into the tuning with my HPTuners VCM Suite and try to redo the shift tables but I'm somehow thinking it has something to do with the power band on the engine aswell. It was nice to drive on flat land or slow in the hills but freeways hills caused it to go downshift upshift, downshift upshift like crazy. How much does one with ECM and harness run these days?

RWD Northstars are also cool but again I'm leary on the fitment and there is 0 tuning available for them. I'm a firm believer that there is a lot of efficiency left on the table by the warranty minded factory tune.

the 4L60e works good , for weird shifting try one of the new 6 speeds without the update
a 4L60e is better than most of the automatics out there , you just got rev the crap out of a 4.2 to get it going , but once you do , it flies

[tcbnj]

Re: GM Commuter Motors

CTX - 2 thoughts:

1) Build a modern day version of the "Typhoon/Cyclone" motor from the 4.3 V6 truck motor and maybe a Saab or other graveyard turbo. I would think it would get decent milage when the turbo wasn't spooled up. And the combo would be all GM : or

2) Consider an LT1, my 95 manual Formula with mild external mods recently returned an average of 23 MPG across 180 miles over a equal combination of highway/2 lane/urban driving. It also has good low end torque. Pulling the entire LT1 with trans from an early 90's Roadmaster would allow you to still claim a Buford powerplant and not be cost prohibitive. :-X

[SpiderGearsMan]

Re: GM Commuter Motors

buy a cheap grand am gt with the 5 speed manual, lots of bottom end torque from the intake leeker -all roller 3.4 - even the 4t40e auto is really solid