Turbo 4.3 in a GN?

[BetMinesFaster]

Ok guys

I own a syclone so i know a bit about them. The rods are just as strong as the 3.8 but the pistons will break in the rings lands. This is due to knock and a bunch of it. The buick genarally get a HG before any damage is done to the bottom end. The 5 bolts per hole on the heads really keeps the spark knock in and it will kill parts. The biggest problem it a syty motor is they came with a really small cam shaft. Those motors don't make any more power after 4800 rpm and this is due to the cam profile.


The Block is the same as a Vin z s-series truck motor. The later model 93ty engine got a diffrent casting # on the head but other than that they are the same.


the best way to do the intake is use a Dry TB from holley and custom do the fuel rails and injector bungs on the ports and you will have a very good flowing intake that will fit under the hood.


there is a guy that turboed a stock 5.3 chevy burban engine and installed it in a ford fairmont and it runs in the 9's with a mp-70 and a set of homemade headers google turob fairmont and you will see

Thanks for some positive input on this stuff! Im not trying to run fron the Buick turbo 6 roots, just hate the prices on some of the parts!

 

[CTX-SLPR]

actually the one to get might be the later design, after smog, because they had lower compression. It would be ideal for boost.

Don't go by that, the Buick 75-76 455 has the lowest compression but has the absolute worse detonation tollerance of any of the Buick Big Blocks. Never compare compression ratios between engine families or head designs because 10.0 in a good fast burn type head could take more booste than an 8.0 compression smog 305 due to the chamber design.

4.1's should not be bored out to 4.3L, you need all the cylinderwall thickness you can get. Best way would be to get an aftermarket forged crank and do the SBC rod trick and get an offset ground stroker for more cubes. My stock stroke 0.030in over 4.1 is 256cid which is 4.2L. Boring it over to 0.060 is risky but not impossible, I think someone is running a production block at 4.060in bore but that's 0.095 over and thats getting a bit too thin for my tastes even with a perfect block with no core shift.

 

[CTX-SLPR]

actually the one to get might be the later design, after smog, because they had lower compression. It would be ideal for boost.

Don't go by that, the Buick 75-76 455 has the lowest compression but has the absolute worse detonation tollerance of any of the Buick Big Blocks. Never compare compression ratios between engine families or head designs because 10.0 in a good fast burn type head could take more booste than an 8.0 compression smog 305 due to the chamber design.

4.1's should not be bored out to 4.3L, you need all the cylinderwall thickness you can get. Best way would be to get an aftermarket forged crank and do the SBC rod trick and get an offset ground stroker for more cubes. My stock stroke 0.030in over 4.1 is 256cid which is 4.2L. Boring it over to 0.060 is risky but not impossible, I think someone is running a production block at 4.060in bore but that's 0.095 over and thats getting a bit too thin for my tastes even with a perfect block with no core shift.

 

[buickbert]

Sheesh, a 500 Caddy engine on boost?

I would guess go for a pre 72 model if you want an honest 400 hp/500 tq.

i once raced a guy who had a 500 caddy in a 86 grand prix. stock long block, all he did was add aluminum intake 850 holley and headers. that thing was a monster at low end. he kept up with my 462 skylark for a while before he started to fade.

theres a guy on v8buick.com that already has a tt buick 350 kit and is developing a tt 455 kit

buickbert

 

["Turbo-T"]

I know my old neighbor used to run 71-72-73 Cadillacs in demo derbies, not sure how often them engines lasted thru a derby though.

I seem to recall on youtube a 78 Caddy running like 12's.....

 

[henschman]

Don't go by that, the Buick 75-76 455 has the lowest compression but has the absolute worse detonation tollerance of any of the Buick Big Blocks. Never compare compression ratios between engine families or head designs because 10.0 in a good fast burn type head could take more booste than an 8.0 compression smog 305 due to the chamber design.

4.1's should not be bored out to 4.3L, you need all the cylinderwall thickness you can get. Best way would be to get an aftermarket forged crank and do the SBC rod trick and get an offset ground stroker for more cubes. My stock stroke 0.030in over 4.1 is 256cid which is 4.2L. Boring it over to 0.060 is risky but not impossible, I think someone is running a production block at 4.060in bore but that's 0.095 over and thats getting a bit too thin for my tastes even with a perfect block with no core shift.

yeah, what he said. can't you bore a 4.1 to be the same bore as a 350? i thought i read a while ago about a guy doing that and using modified SBC pistons AND rods to build his. or maybe it was just the pistons. anyway, that would definitely cut down the cost of building the bottom end, if that's what you're most worried about. the stock buick cranks are pretty stout, so unless you're talking about making it insane you probably don't need to mess with it. the main thing you'd save on with a 4.1 is that you could use all your same headers, turbo, intake, accessories, and wouldn't have to mod the mounts or the wiring harness at all. you just have to put on an oil line and return for the turbo.

or hell, you could always just bore out your 109.

 

[TURBOPOWERED68]

how much bigger can a 4.3 chevy go? 60 over. what that bring the 4.3 up too?

 

[CTX-SLPR]

Roughly 270cid on a stock 3.48in stroke 4.060in bore 4.3L. This is probably why the Busch and ASCA V6's are limited to 274cid, its the max for the Buick V6 in bore and stroke and I'd guess by the limitations of SBC's it wouldn't be too far from the max of a 4.3L either.

A 4.1L has a standard 3.965in bore, a 0.035in overbore would get you 4in which would share pistons with the 302, 327, and 350 SBC, 4.3L 90º V6, and the Ford 302 and 351 Windsor V8's. If you could find a bore and rod combination that would fit within grinding the Buick 2.25in rod journal down to either 2.1in or 2.0in rods you could use any of the above Chevy pistons. I don't know the Ford big end sizes to say if they would offer up a piston and rod combo.

However since this has not been done often I would say that the combination is likely not within economic sense of getting the right piston compression height, bore size, and the corresponding rod length, big end size, then offset grinding the crank to match them.

End the end there are more 3.8L and later 3800 motors out there than 4.3L's because 4.3L's only really came in trucks and vans (small segment in cars in the 80's) while the 3.8L and 3800 came in basically everything but trucks and van. If I was going to choose a replacement for a 109 or other 3.8L engine, I'd base it on an L32/29 Series III 3800 but convert it over to the earlier L67 EFI system to get rid of the Throttle by wire and use a return style fuel system.

 

[BetMinesFaster]

Syty block is the same, crank the same (non balance shaft). Main caps were not (nodular on syty). Pistons were different. (hyper)

Nothing really special in block.

They do have that extra head bolt, but instead you get weak rods.

The buick motors seem to make more power easier than in syty world.

But as mentioned a ls1 might be more budget friendly and make more power.

What is it about a 3.8 that would make it easier to make power? I would think that a properly built 4.3 would make better numbers for a similar investment? You have more cubes, a few head chioces that move good numbers, and plenty of parts to make the bottom end sturdy....plenty of head bolts to keep the gaskers in it....single plane intake converted to fuelie, 100* elbow and ford style TB and some modified TA headers, 76gtq, and a healthy roller cam and your good to roll

 

[turbobob924]

IF GM still offered the performance heavy duty parts them maybe it would be worth trying the chevy 4.3. Since they don;t it will be way more expensive then building up the buick motor!!

 

[bison]

I would avoid the 4.3. Not worth the extra cost of parts to convert when you can find steel LT1 rotaters around pretty cheap. Custom pistons, headers and intake plumbing is still required. Keep in mind the 4.3 is only 4 mains like our Buicks and has weak nodular caps. I doubt the shortblock is capable of reliably holding much more than the weak Buick stock bottom.

 

[WSLN 6]

Don't lose hope.....would be a very unique ride when it is done, with bragging rights over the V8 guys for sure. Nothing worth doing is without it's challenges, and if we wanted the best bang for the buck we all would have gone Lsx with a turbo long ago anyway.
Keep doing the research and have some fun, it's what it's all about in the end.....

 

[BetMinesFaster]

I did some number looking on the LSX, That would be a fortune....Not to mention its an 8.....Splayed 4 bolt steel mains and a good crank and the bottom should stay together fine. The intake is already planned, not saying the 4.3 is the do-all end-all of the matter, just kicking it around. With the right crank they use a standard 350 rod and piston, steel cranks are reasonable, as are the pistons and rods, they are factory roller cam engines so there is no need for expensive roller conversions and lifters, Good aftermarket heads are available. I just dont see alot of a downside.....