i hopefully will have a 85 trans am 5spd at the end of the week. my 91 blazer its replacing has a 4.3 that i was going to rebuild and turbo. if i use all the wiring from the trans am, and the tbi unit the 4.3 should fit right in?? maybe i would need a chip burned? i know i know 8 rule no replacement for displacement bla bla bla, its something different so any thoughts?

 

4.3 is just a v8 with 2 cylinders chopped off, should fit right in. Not sure which motor mounts you would need to use though.

 

you should be able to use the 350 motor mounts because the 4.3 is pretty much a 350 with 2 cylinders lobed off. everything else is the same.

 

first things first, is the car a v6 or a v8? if it's a v6, it will not just drop right in. you have to change motor mounts and bell housings, that's first. we need more info first.

 

By searching on "4.3" and username "ede" (just happened to know he swapped one into a 3rd gen), I came up with https://www.thirdgen.org/techbb2/sho...threadid=81622 .

It doesn't address the turbo part, though. I'd suggest a rear mount a la https://www.thirdgen.org/techbb2/sho...hreadid=272019 , just because I'm completely ignorant about poweradders.

 

go to www.syty.net

syclone and typhoons were 4.3 turbo's. you can also get the special intake manifold that uses the L98 throttle body. check ebay for the manifold.

very good motor, very fast.. a bitch to tune.. use the 749 syclone ecm or ditch it for a FAST set up.

 

Crap pistons. crap rods, weak block to make serious power. It's a 90* V6 so the vibrations are horrible. It takes some cash but a good rotating assembly and a sportsman block would hold up for a long time making gobs of power.


GM makes a block identical to the 400. 4.125 bore only 6 holes instead of 8 in the deck. Combine that with a good 3.75 stroke forged crank(400 mains) and you'll have somewhere in the neighborhood of 301 cubic inches. A stout monster able to do whatever you'd want. Ask yourself why? Is it to be different? Is it for gas mileage? Is it to run the car in a certain bracket? For the money spent you'll get the same power out of a traditional V8 with leass headaches!

JMO

HTH!

 

http://www.machperformance.com/index.htm

check out this site might help with the 4.3 turbo swap

 

Turbo + TBI = for the pros. TBI speed density has no real way of measuring boost without major ECM upgrades and swaps and concocktions. It is a nightmare and a waste of every human resource unless you go about it the right way. That amount of effort alone usually would be in favor of a small block over V6.

 

if your gonna do a turbo 6- find a GN motor- i have seen a couple for sale with less than 100K on them for around 1800$, they use the 200R4, the rotating assembly can handle a decent amount of boost. i run 24lbs with 110 octane on the stock rotating assembly. performance parts are widely available for them, and i think overall it would just be easier. buy the motor- take the heads out port polish throw new gaskets on them and go raceing

 

3.8 turbo of any caliber needs the following:
1. New timing chain.
2. Walbro 340 hotwired.
3. Valve springs.
4. Bigger injectors and good chip. (turbo tweak, red's, or turbo bob)


If you wanna go further:
1. Arp studded mains minimum! Could go billet or girdle as well.
2. Arp rod cap bolts. Stock 2 dot rods have seen 600 hp minimum.
3. Trw's or JE forged pistons. Factory are hypers but hold up well.
4. Port and polished large valve stock heads are 10's capable.


Some problems with the 3.8's

1. 4 headbolts per cyl. instead of 5 for a chevy. Stage motors have 6. Lots of cylinder pressure or a bad tune will lift hg's all day long. Not very forgiving on an overboost condition. Not like a SC where you're gonna have a set boost dependent upon rpm. Boost reference blows off boom 30+ psi there goees your hg's.

2. Rear main seal is a rope seal and leaks, change it out to a fel pro.

3. When having your engine machined have your shop mic the lifter bores. Rumor has it some were out of round causing the #3 lobes to wear away. Sending flakes of metal into your oil and back through your turbo killing the turbo and the bearings. If upgrading cams go with a known good manufacturer.

4. Stock bearings do not like antifreeze in the oil, if you blow a head gasket and create a milkshake, best drop the pan and manually pump oil into the bearings to flush out the anitfreeze or you'll be cutting the crank soon.

On the plus side I've driven and ridden in a lot of high performance cars, not many feel like a turbo buick slamming you in the seat. Some of these engines are producing 600lb/ft at 2800 rpms. That's like sitting at a light and getting rear ended by a semi . The money you'll spend on the tb will be cheaper, there's more of an aftermarket. New stuff is still coming out for these 19 year old cars.

HTH!

 

well now that you said that i have most you listed on my GN- i have the walbro hotwired pump, green stripes, ported polished heads, valve springs, timeing chain, atr headers and 3" downpipe. the rear main seal was replaced when the motor was rebuilt with the felpro, i just dont see the 4.3 swap being economical i havent really researched it but when i search for parts for my motor- i find them everywhere- my friends syclone we sometimes have a problem not saying its not out there- just saying the 4.3 turbo wasnt in as many production cars atleast i dont beleive. i like how the 3.8 holds the pressure- with a scan tool i can run 18lbs on the street with almost 0 knock retard only a little at shifts, with my new alky injection im hopeing around 24lbs on pump gas- damn race gas is expensive. the green stripes arent cutting it anymore now im upgrading to a 60# injector with a new chip and see how that goes. right now with my set up and race gas in my buick im running 11.8 on drag radials. i didnt beleive it first time i did it but its crazy what some fine tuneing on these cars can do- and alot of aftermarket parts lol

 

The stock turbo buick crank has been in the low 10's maybe a few 9's, I've never seen a syclone unbuilt near that. It may be that they have to pull a slightly higher weight, but some TB's are fairly heavy in their own right. When money comes into play the best bang for the buck is the turbo buick.

If you ever notice TB's dont really mph that well, it's all about the 60' and 330'. After the 1/8 mile it starts to nose over per say. There are tons of 12/11/10 second combo published all over the boards. Don't do what you wanna do, just follow what other people have learned and you'll grab a bottom 11 sec timeslip maybe a high ten on factory parts.

The words to live with when owning a buick are"Sometimes you eat the Bear and sometimes the Bear eats you". It's tough you think hey I just ran a 11.30 at the track I'm a little fat up top lemme goose it on the street, oooops got some bad gas and pooooof hg time. Done it three times so far. Don't do the swap if you want something that isn't gonna need more attention than your girlfriend.

There's little quirks with the Buick's. Metal intake gaskets. Oil system designed by a 3 year old. Cam gets it's oiling by whatever the throws of the crankshaft spit up. The tensioners on the stock chain suck(plastic). The gears of the pump eat into the aluminum front cover, headers tend to crack. They're just a few
.


But if you wanna be planted like no other car ask for a ride in a Turbo Buick. Other cars will pull you along up top, these slam you against the seat though...........


Cheers!
I hope this was sufficient to confuse the hell outta everyone

 

i went from my 92 camaro with the 3.1- to my GN, there honestly is nothing like a TB slamming you in the seat- your right that after you get up to speed it does sort of die out. these things launch hard- ive seen where a guy put a straight line down his axel- then pulled it out after some hard launches and it looked like a candy cane. the axles twist up then break. im debating right now i have a 383 im half way done with a 6 speed for it- but now im loving the force fed V6. if you do go the rout of the TB motor- go to gnttype.org they have recipes, i didnt even think about trying to build a 11 second car by adding some here and there- follow everything on the list of the time you want and you will get it- good luck!!

Andrew