JeremyNYR

iTrader: (2)

I've recently worked on a Blazer with a 4.3L engine and learned a good amount about the engine. They share so much in common with the Small Block V8 including connecting rods, pistons, and valvetrain components. They aren't huge on HP and dont rev high, but they have very good torque produced at low RPMs. In that way, they're kind of similar to the L98 only with lower numbers.

After learning all of this, it really made me wonder why a naturally aspirated 4.3L wasn't the v6 chosen for 3rd gens. It would seem to be an easy fit physically since it shares so much in common with the sbc. I'm pretty sure the torque levels are significantly higher than the 2.8L and 3.1L engines, which would make them a lot more fun and feel more powerful on the street. I'd expect the cost wouldn't be the problem since they are relatively simple engines that were already produced in high volume for the S10 and Blazer. The only reason not to go with them that I can think of is gas milage.

Does anyone have an idea about why GM didn't go this direction? Do you think it would've been a good choice?

K-slice

iTrader: (2)

The 4.3 didn't even exist untill 1985, 3 years after the 3rd gens started production. I would guess that GM just didn't feel live investing the money into switching V6's when the 2.8's were already in there.
The 4.3 is an alright engine, but I think it's much better suited to truck applications than cars.

JeremyNYR

iTrader: (2)

I just looked it up and I see you're right about the 4.3L starting in 1985. However, there was an earlier smaller displacement version that was 226ci (instead of the 4.3's 262ci) started in 1980. the earlier version could've been used initially and replaced by the 4.3L in 1985 just as the 2.8L evolved and was eventually replaced by the 3.1L in the F-bodies.

Why do you think it was good for the trucks but not for cars?

K-slice

iTrader: (2)

I've had a 4.3L Jimmy and S10 in the last few years. They were both good trucks but pretty boring to drive on roads.

My guess as to why the 2.8 was the V6 for fbodies (as well as all chevy cars at the time) is that it is more of a car engine than a 4.3 is.
-The 4.3 has great low end torque which makes it good for pulling trailers, or off roading, but the 2.8 can rev higher and gets its peak HP quicker.
-The 4.3 takes almost as much gas as the 350 it comes from, the 2.8 isn't great on gas but better. At a dealership there would be basicly no benifit to getting the 4.3 vs the 305 in the MPG department. Plus it had to compeat with a I4 Musting.
-The 4.3 was evolving to fit the needs of trucks, while the 60* V6's were evolving in vehicles like the Grand Prix and Chevy Lumina.

JeremyNYR

iTrader: (2)

The gas milage is an undeniable problem with using the 4.3L in the f-body. But I'm looking for a more in depth answer than just saying that the 4.3L is a better truck than car engine. Besides, they used 350 TBIs in trucks that were very similar to the 305 TBIs found in the 3rd gens. The great low end torque of the 4.3L that's great for pulling trailers and off-roading is also what made the L98 an incredibly fun engine on the street where you launch very hard if you're able to get traction, but the power dies out higher in the RPM range.

Do you know what the S10 and Blazer weigh? I'm wondering how much more fun it would be inside the presumably lighter body of the 3rd gen. I would expect the cam selection to be a bit different for the application as well.

Pillsbry10

iTrader: (1)

id would say another reason...and probably a main reason is the v6 motor was not ment to be a "desirable" motor to have, it was decent on gas mileage and wasnt much slower than the 305s of the day. having the 4.3 and a 305 motor in the same car isnt different enough to be worth the cost. they really are the same motor overall.

JeremyNYR

iTrader: (2)

I guess that's a good point about the 4.3 and 305 being too close to eachother. One is a 350 with smaller bores, the other is a 350 with 2 less cylinders. they probably had similar gas milage and not a huge gap in performance. It would've been interesting if the offerings were 2.5L I4, 4.3L V6 and 5.7L V8.

Pillsbry10

iTrader: (1)

ill give you that...that wouldve been interesting

however though the 2.8 and 3.1 design was being used in the front wheel drive cars so from a money stand point having them in the thirdgens all went hand in hand. i love my v6 motor its a great running hard to blow up motor

ex-x-fire

Its just the way it happened.
Why didn't they put tpi engines into g bodies?
Why didn't they put tbi on the olds 307?
Why didn't they put the buick 3.8sfi non turbo in g or f bodies in the 80s?
Why did the 2.5l last so long in the f body production run? Hardly anyone bought one that way.

Gumby

Jealousy, the TTA almost never was cause of that and why they played with it to make it "better" then a Buick. Plus guys would have just slapped a Turbo on a cheap base V6 n blew to doors off the V8.


Also member the 4.3 and 3.8 were built at the same time with the same method, take the V8 350 of each division and chop off the back two cylinders, so parts n upgrades are easy to fab and lots of stuff will work still as is.

But the 4.3 is still a turd, but the 3.8s set records.

Think about that then reconsider who had the best Gen1 V8s

92droptopws6

iTrader: (10)

But the 4.3 is still a turd, but the 3.8s set records.

If that's the case I guess the syclone and typhoon are just junk!
The motors that are junk would be the 2.8,3.1and 3.4 in the f body the 4.3 and or the 3.8 should have been the only v6 powerplants available.......

ex-x-fire

You guys ever see the carb they put on the first year of the 4.3L? It was a q-jet 4bbl. & the secondarys didn't open more then half way. Worse then the 305s. I always wanted to grind that tab & see how she runs.

mikey88firebird

I thought I read some where it had to do with emissions. And dont forget the 89 turbo Trans Am it was the fastest fbody for its time ! but there was fitment issues with the 3.8 including using the heads off a FWD 3800 and having to use the 2004r transmission not to mention tuning

auto-x1990RS

they weren't meant to be world beating engines, but stupidly reliable tanks of engines that were decent on gas.

FYI, the 4.3 is 425lbs full dress. the 2.8/3.1/3.4 are around 350lbs. that's a sizeable chunk of weight off the nose. more weight usually means less fuel economy, which is what the 60* v6's were meant to do.

oh and the 4.3 would have been a HORRIBLE choice for an f-body. the highest output of the 4.3 N/A ever was 200bhp and 260btq (as of 2005, the last year for the 4.3). the 3.8 made 200bhp and 220btq N/A.

and yes, the 4.3 in the Typhoon/Syclone's were great engines, as long as you kept them stock. they still weren't world beaters though. they ran out of steam @ 4500rpm, and really didn't like to be revved. it really is a truck engine.

Gumby

Go grab either one bone factory stock, Ill grab a bone stock Turbo GN and we will see.

K-slice

iTrader: (2)

Wow there's a lot of engine hating going on here!
Can't we just say both engines were good at the jobs for which they were built? The 4.3 was the BEST engine to get in a Blazer or S10, however it had no place in an Fbody or any other car. The 2.8/3.1 also did their jobs well in the Fbody and that's why they stayed for the entirety of the generation.

RT66DAVE

Gentlemen, althought the 90 degee v6 started in cars in the late 70's, The 4.3 was used in trucks to provide better torgue & fuel economy than the 2.8 could as used in trucks (s10's). The 60 deg 2.8 v6 came out in 1980 in the Chevy Citation. The 60 degree v6 was smaller & lighter and was a big factor in GM meeting the CAFE (Corporate Average Fuel Economy) imposed on auto makers at that time. Producing millions of 2.8's and 3.1s boosted the CAFE numbers for GM as a whole. The 3.8 started out as Buick's small engine (a 225 ci v6) in the mid seventies and it evolved into the 3.8 , which has proven to be one of GM's better engines due it's power & reliabilty. Each engine had to go through 50,000 mile emission certifications ( a costly process) , so factor those things all in and one can speculate that due to CAFE goals is why the 4.3 wasn't use more. I would have liked to have seen either the 4.3 or 3.8 used in third gen F cars. it would make some interesting choices today for street projects.

92droptopws6

iTrader: (10)

I have built both and they both have similar weaknesses "Crankshaft" being the largest problem........ The ignition system for the 3.8 is way better stock for stock but that's why FAST is in business. Both engines are great, is my point.the others should have only been in smaller cars.