4.3 Supercharged Chevy

[itsnotanova]

Originally Posted by Qingdao

So 5 speeds can't take the torque?

I have decided to tone it down a bit on the engine. No aggressive cam, light boost, stock or dish toped pistons, and only a 25 shot of nitrous at best.

I'd say 300#s on a good day.

I'm guessing you're a chevy guy? The audi/porsche 5 speed is like a T5 and the 986/987 6 speed is like a T56 in terms of power it can take. What you're doing is like connecting a SBC 350 to a T5. Sure it might work, but it won't last if you try doing any kind of aggressive driving. You're kind of limited to power with the 4.3 cast crank but even in stock form I think it's too much for the boxster 5 speed

[maytag]

Originally Posted by Qingdao

I have decided to tone it down a bit on the engine. No aggressive cam, light boost, stock or dish toped pistons, and only a 25 shot of nitrous at best.



I'd say 300#s on a good day.

I'm all for creativity, and even mods just for the sake of modding.

But I gotta ask, gently; if the goal is 300.... that's a poop-ton of work for 300..... so,.... why?
I mean.... I've done my share of gm v-6 stuff... mostly 3.8's (wasn't the 4.3 the truck motor?) And I get the fascination with turbos on 'em.... but otherwise?

It just seems like SO MUCH WORK for a 10% hp increase over a Porsche 3.2 that bolts right in.
?
Respectfully, of course.

Sent from my SM-G970U using Tapatalk

[Qingdao]

Originally Posted by maytag

I'm all for creativity, and even mods just for the sake of modding.

But I gotta ask, gently; if the goal is 300.... that's a poop-ton of work for 300..... so,.... why?
I mean.... I've done my share of gm v-6 stuff... mostly 3.8's (wasn't the 4.3 the truck motor?) And I get the fascination with turbos on 'em.... but otherwise?

It just seems like SO MUCH WORK for a 10% hp increase over a Porsche 3.2 that bolts right in.
?
Respectfully, of course.

Sent from my SM-G970U using Tapatalk

I can understand confusion. LOL

Most of this work is for the blower right behind my head. Just want the VEEEEE sound. Addition of power is a side effect. I'm a strange one.

I'm toning it back to about 300 because I don't want to spend more than I paid for the car on a transmission. At least not right away. … Who knows in a few years once I get the body and suspension the way I want them I might re-visit the trans and engine output. Typical Chevy problems; engine's got more potential than any trans can handle.

Work yeah, but have you priced a 3.2 lately? If I went to the larger tranny and pumped up the 4.3 to a respectable output I'd still be paying less than swapping the engine alone. (side note after the clutch/adaptor purchase I'm in $3500 car purchase included)

Another reason for the 4.3 is I got one when I bought my garbage scow of a pickup truck. I'm about 100% certain it has jumped timing, and it still runs (I just advanced the distributer so it only pings a little). Well 2 years of driving essentially broken and it keeps ticking gives me the impression that its a VERY robust and well built engine. What better engine to put in a car that is less than easy to access the engine?

I am reminded of building my RX 5 years back. The trans always is the compromise area. I had to limit my output on that engine too. But like then I want the engine noises from the blower now; at that time I wanted the wooosh noises from a turbo, the power increase is a side effect.

[Qingdao]

Originally Posted by itsnotanova

I'm guessing you're a chevy guy? The audi/porsche 5 speed is like a T5 and the 986/987 6 speed is like a T56 in terms of power it can take. What you're doing is like connecting a SBC 350 to a T5. Sure it might work, but it won't last if you try doing any kind of aggressive driving. You're kind of limited to power with the 4.3 cast crank but even in stock form I think it's too much for the boxster 5 speed

Never really was a Chevy guy, but working in a shop for almost a decade now I respect their engines. Everything else about GM is garbage, but there engines are nothing to shake a stick at.


Hmm.. It just costs so much to swap that trans. Other than the longer shift cables, does it require different axles?

I think I'm going to try the 5 speed for now and then later on swap over to the 6 speed when it breaks. I mean I have a 5 speed now. Why not have some fun and break it. \m/

[maytag]

Originally Posted by Qingdao

Most of this work is for the blower right behind my head. Just want the VEEEEE sound. Addition of power is a side effect. I'm a strange one.

Actually, that makes total and complete sense to me... maybe I'm strange in the same way, but I fully support all sorts of machinations for the right sound...

Carry -on!

And yes, the 6-spd has different axle flanges. I'm told that they can be swapped over though. Also a different input shaft, so clutch would need to be changed as well. (Disc only, if you start with the right clutch)



Sent from my SM-G970U using Tapatalk

[Qingdao]

This is the level of crazy I am at.

That's my dually RX7. LOL


https://www.youtube.com/watch?v=FjH_e1V_PYc

^^^ this is my inspiration for the mid engined blown car.

[itsnotanova]

Originally Posted by Qingdao

Hmm.. It just costs so much to swap that trans. Other than the longer shift cables, does it require different axles?

I think I'm going to try the 5 speed for now and then later on swap over to the 6 speed when it breaks. I mean I have a 5 speed now. Why not have some fun and break it. \m/

Axles, uprights, calipers, transmission mounts and somewhat the aluminum belly pan but that can be modified easily. That's if you go with a 986 6 speed. A 987 6 speed requires modifying axles too

[Qingdao]

Waiting for Kennedy...

I started working on the subframe. I figure I don't need the engine in place to start on that.

The plan is to run two of these square tubings from the cross member by the bellhousing strait forward and then bolt them to the under body of the car (with a substantial backing plate of course).

Then to give it some more strength I am going to run a bar from where the aluminum skid things on either side of the body and attach that bar to the two running the length of the car.

These are the bolt holes that will secure the subframe to the body. I inserted some steel pipe to give the square stock some "anti-squanch" power. The backing plate I am going to put inside the car (under the seats) will have two M12 bolts welded in place. In my head it should be easy to bolt this subframe up, but its just in my head atm.









On a side note I sold my M96 at a whopping 580#s. I was just looking for a cheap replacement engine when I went with the 4.3; I didn't expect to loose almost 150 pounds of weight.

[robdelorenzo]

“I love engine swaps so don't take this wrong, but won't you have a huge issue with how tall the motor is? Let alone with a blower on top

I hope so. I'm gonna build a plexiglass top. I wanna see this...thing.”

This line had me howling
Gotta love the enthusiasm and creativity on this forum.

There are so many people that know these cars well on here that it’s not even always about budget or $$

Anything is possible with a little imagination.
Well done, enjoy the car!

[Qingdao]

Well that cross member isn't as strong as I remembered when I took it out. Its quite thin if you don't know. So I made it stronger as it is going to support an engine that weighs almost 500#s. This is just tacked on for the moment (ran out of wire feed and I don't like my skills with my arc), but the bolt holes match up.

[Qingdao]

Welded my little triangles in there.

God help me I kinda like the red paint. lol

[Qingdao]

Tacked under the car.




There is a reason why this stuff was $10 for an 8' piece... lots of not only rust.





Once again... the red paint.






Now just one more brace across the middle, like east west.

[Qingdao]

Subframe is done; well for the most part. I want to make it into two pieces cause its a nightmare to put it in place, but for now it will serve until I get my adaptor from Kennedy.


I'll say this you can't say **************** about this car and rear structural rigidity.

[Qingdao]

This thing fits almost well.

I was hoping it would be shorter, or I'd have more length to play in. But looks like I'm going to have to re-work the trans mounts. Oh well so much for stock drivelines.

The oem subframe connector thingy doesn't even have a prayer of going in with this engine. So gonna have to re-fab that up. No big deal there, cause I already made that angle iron piece; just have to grind the welds off of it and use it solo. I might possibly just go another direction... Haven't made up my mind yet.



Do any of you guys know which direction the coolant goes ?????

Is this the hose going to the radiator from the engine like hot out of the engine???





Does this heater core hose go into the heater core from the engine? or is it the return from the heater core to the engine?

[Qingdao]

Oh yeah, here is the old girl in the engine bay.

[Qingdao]

Almost final product. I didn't have enough gumption to put it back under the car and take some pics... maybe tomorrow.

[Qingdao]

There she is no chains no straps. Perfectly level side to side, and the trans sits at the OEM height (just back an inch and a half).

Gonna get my hockey pucks soon enough and I can fab up the trans mounts.

Then the fun can begin.. Exhaust fab, coolant lines, ac and power steering.

[itsnotanova]

Will your shifter cables reach the transmission? I think the 6 speed cables are longer but don't quote me on that

[Qingdao]

Originally Posted by itsnotanova

Will your shifter cables reach the transmission? I think the 6 speed cables are longer but don't quote me on that

I've been wanting to check that, but I've been pre-occupied with making the trans "cradle". In one hand they route over the idler pully in the same manner as on the flat 6 and they should sit right in the V almost lower than the H6. BUT the engine is a bit taller so IDK.

I figured the V8 guys don't have too big of an issue worst case I can route 6 speed cables the same way the V8 guys do (under the V???)

[Qingdao]

Originally Posted by itsnotanova

Will your shifter cables reach the transmission? I think the 6 speed cables are longer but don't quote me on that

So yes, 5 speed cables can be used... you got me motivated to route them.

They slip under the V with no fuss.











This is the start of the trans "cradle" or whatever. I made this thing that grabs the trans nice and tight then used some flat bar to make a mounting area for a pair of hockey pucks. The pucks will be supported (where my hand is) to a cross beam of some kind (that will be made at a later date... tomorrow???).