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mikey_d05

mikey_d05

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Alright, I've been chasing a supercharged 3.8 for my buggy project because of the decent power, compactness, and light weight.

However, I went to the local yard today because they had a s/c 3.8 that had a manifold fire and I figured I could use it as a mockup motor. The mechanic I was dealing with claims that the last aluminum head/iron block 5.3 they shipped out only weighed 550 lbs, and their going rate is under $500.

I call bull****, since the going rate for an s/c 3.8 is around $1000 so we walk back inside and they have one in the warehouse for $475, '03 Avalance motor with 68,000 on it. That's kinda hard to beat.

So, almighty CK5, I'd like opinions. I'd rather not just get the "more power, V8, ugh ugh" responses...I can bump a supercharged 3.8 to the same range as a stock 5.3 pretty easily, and I'm aiming for this thing to weigh in at about 4000 pounds, so every little bit counts.
 
Yes you can bump up the power of the Buick based motor , but it still lacks the torque on the low end .

Horsepower is torque x rpm / 5252 .

So the newer 327 wins , albeit a little heavier :thumb:
 
Keep in mind that I'm going from probably a mid 5000 lb rig with 120 hp on a good day to a hopefully sub 4000 lb rig and we're talking about the difference between 2.5 and 3 times the power.
 
Are you building a buggy from scratch? Any interest in being lighter than 4000 lbs? Do you think you need this kind of power?
 
All tube this time. Yes, I'd like to tip the scales at less than 4k, but I'll have to use my current axles for now, which puts me at a 500-600 lb. disadvantage anyways. Don't need it, but when the V8 is half the cost of the V6 in the same form, it catches my attention.
 
At most you have 1500 lbs of unsprung weight (axles, tires and wheels).

You could easily (and relatively cheaply) build a chassis and drivetrain that weigh 1500 lbs.

Do you want the power of a bigger motor (V8 or supercharged V6)?

How many seats are you planning for?

And I realize that I'm not directly answering your question :D
 
My steel beadlocks and boggers weigh 160 lbs. each. That's 640 lbs. in wheels and tires. My 14 bolt still has drums, so I'd be willing to bet that I have over 1500 right now. I have a set of Iroks in Iowa and hummer rims getting recentered, but I doubt they're a ton lighter considering all the steel in those rims.

Figure the motor weighs 600 lbs. dressed just for conversation, the transmission I'd like to use is 130 lbs. and my t-cases can't weigh over 100. Round up to be conservative and that's 900 lbs., which leaves 600 lbs. for a chassis...more than enough.

So, figuring 1500 for unsprung weight, 1500 for chassis and drivetrain, that leaves me 1,000 pounds for radiator, shocks, links, seats, tool box, fuel, cooler, etc., etc., etc.

Is it unrealistic to aim for 4,000 with a 2 seater and a decent sized mill?

Yes, I'd like to have 200 hp. at the very least. An n/a 3.8 might do it (my Grand Prix does pretty well) but when we're talking about having to rework a ton of **** if I want to switch motors someday, why not go for the 250+ range?

I'm curious as to what precisely you're getting at, since you always seem to be one step ahead of me. :haha:
 
mikey_d05 said:
I'm curious as to what precisely you're getting at, since you always seem to be one step ahead of me. :haha:
Click to expand...

Lighter = better in the rocks, which you already knew.

More power = stronger drivetrain = more weight.

What lightweight trans and t-case would you use? I wouldn't plan on the 'Yota trans surviving behind a V8 (I assume you have the gear driven t-cases)
 
IIRC an SM420 weighs about 130 dry without a bellhousing. I'm planning on using my geardriven 'yota cases behind that until they blow up once or twice, and then parking it until I can afford a 4 speed atlas. :haha:
 
You could it well under 3000 pounds if you used aluminum transfercase and 1/2 ton axles with the 3.8 , or even a nice 4 cylinder . The lighter it is , the easier it is on the drivetrain .

If you use aluminum transfercase for this , mimic the stock type of mounting it .

Look at Marvs current buggy :thumb:
 
My t-cases are aluminum. Don't really want to go back to 1/2 ton stuff. My end/dream stage is 609 front, 9" rear, 42" iroks.
 
IMO, the 5.3 is just better suited to trucks than a 3.8. period. you'll make usable torque in a convenient rpm range instead of having to spin it up. and, a naturally aspirated motor is simpler (and cheaper) to care for than a forced induction one. my friend's bone-stock 5.3L 2005 silverado crew cab is as fast as his 99 grand prix gtp with exhaust, intake and minor engine mods. the 5.3 is just a better motor, IMO.
 
Well , if you want the heavier drivetrain , use the bigger motor . You would be happier with the lower end .

There really can't be lightweight without making it ALL lightweight :thumb:
 
pauly383 said:
Well , if you want the heavier drivetrain , use the bigger motor . You would be happier with the lower end .

There really can't be lightweight without making it ALL lightweight :thumb:
Click to expand...

I was planning on using an SM420 and toy gear cases anyways. The only place I think I really have unneccessary weight planned is the transmission and axles...I already have my 60 and 14 bolt and I don't want a slushbox. Are there any any aluminum cased manual transmissions that you think would hold up?
 
Yeah , probably a Toyota tranny , or an Isuzu truck tranny . First gear would never be as low as the SM420 , but its lighter , makes mating to the Marlin type crawler easy .
 
There's another conundrum for ya...:haha:

The R151 is easy to put behind a standard 90 degree chevy pattern, but I'd be worried about it holding up. The R151 is a bitch to put behind the 60 degree buick pattern, but I think it would do fine in that app. :doah:
 
Weight, AFAIK a 465 has about 40 pounds on a 420 or 435...a 5.3 is kind of a whore to put any sort of manual behind, so I'd probably have to pick a different transmission or go to a slush box (not gonna happen right now), a 3.8 is way easier to put a manual behind, but I have to find a 3.8 first. :doah:
 
Maybe the real question here is how do you want it to be, as in, what is your ultimate wheeling buggy?

I'd assume you really only want to do it once. If that is the case, then figure out what you think would be the best combination. If that involves the ?? motor, then find it, use it and make it happen.

I can't think of anything worse than building a buggy and spending the time and cash to get it put together and think what if....

Personally, I would have to lean toward torque vs. Horsepower

Reliability vs. lightweight.

Granted some of these can be had in the same package but that's just my prioritizing a build.
 
Maybe I should just buy that damn Caddy 500 back from you. :haha:

Thanks Kert, I guess that puts a new spin on it that I really hadn't thought a lot about. Personally, I think the L47 (olds 4.0) would be the coolest motor to build, but there aren't a ton of options if it doesn't have enough power for my liking when it's done...and to the best of my knowledge nobody has done it before except the sand rail guys. I guess I could use a megasquirt in lieu of the traditional computer to try and squeeze a few extra ponies out of it.

Think it's worth going back to the yard and buying the blown one they have for an experiment? :dunno:
 
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