Trying to think of the best setup to get great MPG, and at the same time raise my HP up from my 2.8


Input? Might be a nice swap, especially with the 4.3 supercharger

 

4.3s are fairly thirsty from what I have heard, it wouldn't be an easy swap, though would be interesting, and those things sound pretty damn good and go fairly decent, even when pulling a camaro(while in a truck that is). Honestly, a 3x00 would probably be best for what you want, assuming you keep it gm and a 6er. I would go with a 3500 personally. As a side note though, I thought power wasn't your thing o.O? Oh and if you have the cash a 3.6 LLT, thats what I plan to get when I finally land a job, going to sort out the rest of my car and leave the engine as is then save for a 3.6 I think. I'm drooling for that 300 hp aluminum v6.....It would give me a weight to power ratio of 10:1...before even modding the engine...

 

somone on the board did this swap well atleats installed everything before pulling it all out. theres a thread documenting it in the engine swap forum i belive.

its pretty much a bolt in deal with some motor mounts form summit racing

if u do it get a vortec motor but ditch the cpi injection system and pick up a marine mpfi manifold

btw hot rod or high tech chevy did a 4.3 with a centrifical supercharger and laid down over 500 hp on a pretty stock motor

my next toy will be a camaro with a 3.4 dohc motor or a 4.3

 

Your 2.8/T5 combo weighs about 450 lbs, A 4.3 with a T56 would be about 575 lbs... you'd be adding another 125 lbs to the front of the car... At that point it would be a wash unless you boosted it


A 3500 with a T5 would be about 425 lbs and give you the same HP as a 4.3, slightly less torque but a mild cam would fix that easy.

 

I'm not into power or speed, though a little more than what I have now would not be a bad thing.

I'm in love with the concept of a t56, I love the dual overdrive on them for highway driving. If a 4.3 gets better MPG than a 5.7, couple that with a t56 and I might have something really nice.

 

i think the 4.3 would be better for a mpg standpoint even with the added wieght stock they already have some great low end grunt, swap in a edelbrock towing cam and the thing could be a milage beast with the right set of gears

whats the power curve of a 3500 look like its been a while since ive seen one

 

my dad's s-10 didn't do much better on gas when it was a 4.3 than it does now with a 350. I'm not a fan of the 4.3s, really...I say stick with the 6/60 or go small block.

 

well, a 305 tpi is always an option. What worries me about those is I hear some people brag that they get 26MPG, and then then I hear some people complain about 12.

I was also thinking of a 4.8 or 5.3 ls1, but that's a long way to go just to save on a little gasoline

 

I'm pretty certain that the 4.3L V6 has the same bellhousing bolt-pattern as the SBC, so just get a T56 that'll bolt up to a SBC-style bellhousing bolt-pattern.

And here are some articles on 4.3L V6 power:

http://www.hotrod.com/techarticles/e..._engine_build/

http://www.hotrod.com/techarticles/e...arger_install/

 

turbo the 2.8 i avg around 36mpg highway and thats with a 4k+ stall and 4:10 rear gears.

though if u go driving around with ur foot in it all the time u can empty a tank of gas in very short time

 

The 4.3 in any form has never been known to get good mileage. Some better heads would do wonders for it though.


3500 is 201 HP/221 TQ from GM, I've dyno tuned stock 3500's with a 5 speed to put down over 200 hp to the wheels so maybe 230 @ the crank. Those cars weigh between 2800 and 3K lbs and get around 30mpg on the highway.. some higher. Usually 15-18 city.


I looked for a while on the net and couldn't find the GM released 3500 dyno graph, i have it on my server at home.. i'll post it up later.

 

[QUOTE=project89;5038353]turbo the 2.8 i avg around 36mpg highway and thats with a 4k+ stall and 4:10 rear gears.

My 2700 lb corsica with a 3100 only gets about 26

 

[QUOTE=Project 3.4 Camaro;5038656]Torque management kills it. I hate torque management, for that very reason.

 

I think the 4.3 is a 5.7 minus two cylinders....the 89 TBI 4.3 in my s10 gets horrid gas milegae...I think I was running between 9 and 12mpg....thats of course before i tuned it up and fixed the problems the previous owners awesomeness did...i dunno what it gets now cause its apart.

Still I dont think itd get that much better. Its a good motor for a truck or van though...seems torquey and good for carrying loads and stuff, but its not super fast or anything on the higher RPMs.......I like it cause its darn reliable and its easier to work on than the MPFI 2.8s... i dont think itd be to good in a 3rd gen though...its a bit hard for me to criticize it as mine has a good 200,000 on it at least..but at least its been reliable

 

[QUOTE=Six_Shooter;5038843]What is torque management, and more importantly is it why my car is gutless on the highway unless I gun it? Drives me fricking insane, I can't make minor speed increases to keep up with the car in front of me, or pass someone or get up a hill without giving it an excessive amount of pedal for the speed increase I need...Also realized today that I don't think it downshifts to 3rd going up hills which seems odd, cause I could swear my lumina and buick did, but I don't think the corsica has done it once.
I decided several days ago that it seems to be going into some kind of lean mode on the highway, cause it sounds like its running lean, a sound I know well on that car cause on cold starts sometimes it runs like crap and can stall out(Gotta love ghost problems, no ECU codes or any apparent cause, though I suspect its a temp sensor on its way out or some such). But yeah, would be nice to wring some more MPG out of it and or be able to increase speed efficiently, which in and of itself would give me better mileage, it runs fine, its just like there is some kind of impasse it sinks into on the highway, where it won't really speed up unless I bring the throttle out of it, I really suspect its going into some kind of fuel trimming lean mode and pulling fuel, or that its ECU learned its driving habits from the geiser PO.

 

found this...

What is torque management and how does it affect me? This question has been asked by many a Gen 3 owner and it has been my experience that there is a lot of misinformation out there that has been incorrectly quoted as fact, when it was anything but. I hope that this write up helps everyone better understand this aspect of the PCM.

The first question that needs to be addressed is, What is Torque Management (or TM and many refer to it)? TM is part of the programming in the PCM (powertrain control module) that ultimately reduces engine torque when the transmission changes gears. Its purpose it to increase the longevity of the transmission and drivetrain as a whole.

What cars have TM?
All automatic transmission F & Y body cars have TM reducing engine torque during gear changes. Please note that TM is only "active" is automatic transmission cars ( F & Y body). Manual transmission equipped cars do not make use of TM as the average manual driven car has a different kind of power reduction during gear changes. When the average Joe is driving along and goes to make his 2-3 shift, his right foot comes off the throttle, his left foot dis-engages the clutch while he changes gears via the shifter. Once the shift is done the clutch will be re-engaged and the throttle will be depressed once again. Therefore, TM is not necessary in manual equipped cars, as the average way that a manual is driven has a sort of self imposed torque reduction. Note, this is the way the "average" person drives, not the way a lot of us drive.


How does TM vary by year?
While its operation is generally unchanged, the amount of torque reduced and the speed at which it is reduced varies. Generally speaking, Earlier models (98-99) reduce engine torque a little earlier but ultimately can reduce torque by up to 30%. Again, in general, later models (00-02) reduce torque a little later, but can ultimately reduce engine torque by up to 37%. More on this to come.


So how does TM work?
All of those wonderful sensors that allow your engine to operate so well also supply the inputs that allow TM to function. While I am not going to get into what all happens mathematically, the PCM calculates the "Delivered Engine Torque" based on numerous inputs. The PCM then retards ignition timing to reduce engine torque by a predetermined percentage based on the engine's torque output.

 

I don't see how that would hurt mileage if its only during shifts...and from the sound of it it seems like it would only be in cars with a lot of power, esp. since it says fbodies and vettes...

 

Torque management is in pretty much everything now and effects more than just shifts.

 

Even on a 96? anyway to disable it? and whats the purpose of having it on all the time...seems pretty stupid, especially if it hurts mileage instead of improving it...usually they do things to improve it not harm it...

 

yea, my G35 daily driver has a bunch of torque but, it's a dog off the line...go figure

 

It's government BS, somebody somewhere convinced people that accelerating slowly, even through use of electronics to retard timing, saves the planet.... :facepalm:

What they need to do is look at the real numbers and realize that if they just started with smaller power plants, and didn't try to reduce the overall power output, then the cars would run more efficiently, and burn less fuel.

 

find somone with hptuners and they can remove the tm for u, guy over on the turbo forums did it and he said its a world of difference even just cruising around

 

Do they have any systems compatible with a 96 corsica with a 3100, cause I did look into those but they don't have any specific to it, though I would think the engine would be all that mattered...

 

theres a few ppl who do tuning on my local forums all ask them if hptuners supports that i belive it does

 

I'm going to revise this question. I still haven't gotten the thought of matching a V6 to a T56 to get an ultimate highway cruiser car. At those RPM's, 30-35 MPG should be easy

What about a 3.8 with a t56? If I went that route, would I use the T56 from the LT1 engine, or the LS1?

 

well they did make the 89 tta with a 3.8 so its not impossible and would probably be the best idea. I don't think you would also have to change the transmission unless i think they use a 200-4r, but same bolt pattern. Don't hold me to it but i think that's right.

 

No, not the same bellhousing pattern.

The Buick 3.8 uses the BOP bellhousing pattern.

 

I have the 4.3 in my truck with a 5 speed manual and get between 23-30 mpg. I like the motor and think they be a great motor if done right and the 3.8 is a great motor too. I'd like to see either done

 

unless...

http://www.weirhotrodproducts.com/index.html

 

The 4.3 is basically a sbc with two cylinders missing . The t56 best suited for this swap would be from a'93-'97 LT1 car. The LS1 bellhousings are one ear off from fitting . And while you are in there, get a set of internal shift forks for a Viper t56 , much stouter than the GM counterparts. I had a '97 S10 with a 4.3 Vortec , it didn't seem to do any better on gas than the '99 fullsize 350 Vortec I drive now. A few mods could make it a fun combo.

 

4.3s are one of my favorites, and I still daily-drive one. They can return surprisingly good MPG, if you gear and drive them right, plus minimize drag. But low RPM plus small engine is NOT a guarantee of good MPG, and generally doesn't work that way. Getting a 4.3 to 30 MPG is possible, I've seen 28 at 70 MPH, so just slow down to 60. Getting a 3800 Series II to 35 MPG is practical, my old '96 Bonneville did it. Getting an LSx to 35 MPG is possible, GM did it with an AFM ( but not VVT ) LS2 'vette with a T56. Getting a 6.2 diesel to 35+ MPG is easy. But 4.3 swaps belong in the Engine Swap sub-forum, not in the V6 sub-forum. I have installed a 4.3 in my '84 Trans Am, and I did a how-to-install thread in Engine Swap.

 

Forget about the 4.3 for a minute. I'm now asking if anybody knows the best way to mount a 3.8 to a t56. Would I need the BOP bellhousing I posted about earlier?

but then again... It probably make more sense to put a 4.8 or 5.3 LS1 in there.

 

That was always the proof in the pudding that the chevy 350 isn't so great.

The first 3.8 Turbo's were just a Buick 350 missing the back two.

They get 700+ HP out of the early cold air turbo 3.8 with little work.

The same work can't get close to that out of a 4.3

Hence it has to be the mothers DNA we'll call it that makes it special.

And why Jim Burker got 1000+ with little work when it turbo'ed a Buick 350.

More proof that the "be all end all" chevy 350 is a boat anchor by design, 2 less cylinders or not

 

That bellhousing SHOULD work for putting a T56 with a Buick 3.8 V6.

 

If not, you can get adapter plates for around $100 to bolt any trans to any engine.

Old Buddy put a T56 behind a newer FWD chrysler, the bodys came stamped for RWD and the engine was not transverse so it was beyond easy.
Lost contact mid through but I know he got it done.

 

There have been several major versions of the Buick 3.8, and only the GN-specific blocks, also used in T-types, GNXs and our '89 TTAs, can take 700 HP. Late-'70s versions are BOP-pattern, but the only version to seriously consider is the Series-II, introduced for 1996. The best version came with the supercharger in the FWD big cars, it got a different crank, better rods, better pistons, et cetera, but the heads are different. They have injector holes, since the blower prevented keeping the injectors in the intake manifold. Normal Series-II versions are only safe for 6 psi intercooled, which won't get you past 300 HP. And the Series-II uses the same bellhousing pattern as the 2.8 / 3.1 / 3.4 The huge results from the GN crowd doesn't prove the Buick superior to the 4.3, and in fact the Sy/Ty crowd has far exceeded the best the GN crowd ever did. Bolting the '93-'97 T56 to a 4.3 would be relatively easy, far easier than attaching any version of the T56 to any version of the Buick 3.8