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BBC vs LS#/X Need Advice Please

Thanks so much for the advice. MPG is not a huge priority and I know it will never be good; however I would hate to pay $10k for a guzzler when I could have gotten 3 mpgs better from and equally powered ls3.

Question though, what do y'all have against the ram jet?

Thoughts about using the ramjet intake and fuel rails on a 496 or is Holley, fast, etc the way to go?

Old technology VS new technology. IMO this really isn't even a question. I would go with the newer technology if I was investing that kind of money. In the future most of your aftermarket support is going to be towards the newer engine. The old chevy motors IMO will quickly become dinosaurs. Inefficient, less reliable and just plain more work.
 
This LS3 just has a cam and headers making 517hp with a pretty smooth power curve:


Hurry up warentee, I really want to put a cam in my Camaro now... :deal:
 
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Over on the 5th Gen Camaro site there are guys with the LS3 that have a cam, supercharger, tune, headers, and exhaust making 550-600hp. All very streetable and reliable with pump gas.

Once again, these engines can certainly make the hp, but I am under the impression that for our heavier, ultimately lower top end speed vehicles, its is the low-low-end torque that gives the most perceived performance. By perceived, I mean the most enjoyable/readily apparent performance increase.
 
They might make horsepower, but they lack low end torque. Buddy had a GMC with the 5.3 in it, supposedly close or over 300 horse, and well, I wasn't impressed. I have an '08 Tundra with the 5.7, that is 370-ish horse and 380-something torque and that doesn't pull as hard as a big block. The 4.30 gears and 6 speed auto gives it the "feel" of having alot of torque/power. My old 97 with the Vortec 454 seemed to pull much better than this truck does.

You need the low end torque to get you going, not high RPM power.
 
They might make horsepower, but they lack low end torque. Buddy had a GMC with the 5.3 in it, supposedly close or over 300 horse, and well, I wasn't impressed. I have an '08 Tundra with the 5.7, that is 370-ish horse and 380-something torque and that doesn't pull as hard as a big block. The 4.30 gears and 6 speed auto gives it the "feel" of having alot of torque/power. My old 97 with the Vortec 454 seemed to pull much better than this truck does.

You need the low end torque to get you going, not high RPM power.

So you gear it deeper, big deal. If you were terribly serious about balls out "low-low rpm tq" you'd be talking Cummins swap IMO.

Even the lowly 6.2 NA diesel probably makes more "low-low-rpm tq" than most gas V8's, and having owned a couple I can attest to the instant off idle tq you feel...however they do lose steam quickly. I'm gonna go out on a limb and say the LSX might not have the extreme low end tq, but once the tq really comes on it pulls damn hard and easily pulls into a higher range than most people would want a big block to go to. So, gear it appropriately.
 
Still leaning towards the RJ bc of the ease and that it is an actual known. Sounds like this HP3 crate that never ended up being produced was probably the answer to my problems. Anyone heard of performance crate built from the 8100 Vortec?
 
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Not that it really helps, but to add some entertainment to the thread, Here is a 454 LS motor being put through its paces,


Vs. a Ramjet 502.

 
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He mainly just wanted to save weight, I'd say big block, I guess the ramjet is fine, i just can't imagine dropping 10k on something that only makes 500hp though

Tim cameron has already been through at least one LS engine
 
I see your point, but as far as the $ goes, I have not really seen a less expensive EFI option (using torque as the metric, instead of HP)
 
Dyno Numbers

TRustyk5 posted this sweet ls3, which I got dyno numbers for

http://www.jegs.com/i/Blueprint-Engi...ductId=1647808
(black and white pic)

I am now leaning towards this 489 stroker (pretty much exactly what I was originally going to build, other than they can do it about a grand or two cheaper than I estimated, plus I get to sell the Gen VI that I have.

Can get it with the Fast EFI - setup, installed, tuned, dyno'd and warrantied for a little under $10k

http://high-performance-engines.com...Screen=PROD&Store_Code=ATK&Product_Code=HP41C

Its dyno numbers are the color pic.

As you can see, LS3's (at least the ones I have found) do not generate big block torque. They are are bad ass, lighter engines, that would send a camaro down a drag strip, but I think the BBC is better suited for Betty.

PSLS4270CTC.jpg

HP41C.jpg
 
May have spoke too soon

Well, I may have spoke too soon. ATK's 489, ultimately wins out in hp & tq, but the RJ still beats it in TQ on the low end.

Pro's for ATK's 489
$500ish cheaper
2 year warranty (extra year, but those warranty's sound like crap anyway, good luck getting anybody to pay or give you a new engine)
EZ-EFI (not sure if that is much of a pro)

Cons for ATK
Gen 4 or earlier bbc
Should be tuned close to optimum

Pro's of 502 RJ
Mass produced, has some reliability/repeatability data vs a local shop
Gen 6 bbc
Should have hp on the table and tuning upside

ATK 489 vs 502 RJ.jpg
 
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Truthfully i think you are already talked yourself into the ramjet and no amount of convincing otherwise would make any difference. So just order the puppy up already!
 
Somewhat true. Maybe it's an engr thing, but I am looking for proof in a world that is frought with opinion. Engine will be ordered by end of next week, regardless. We can get to four wheeling and stop nit-picking.

I will also give a mpg and rear wheel dyno update for anybody who may want to know the outcome.

Thanks again.
 
Tuning I guess would be the 489, future mods would be ls3. Am I naive to think that if drop in 550 ft-lbs, that I will never have to make mods?
 

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