2.3L Quad 4 vs 2.4L twin cam
Moderators: The Dark Side of Will, Series8217
2.3L Quad 4 vs 2.4L twin cam
Was the twin cam a continuation of the Quad 4 or a new slate design? What is the bore spacing of each?
The Twin Cam is a close relative of the Quad 4, most things are interchangeable, like the crank (with some bearing resizing) making a stroker Quad 4. The twin cam has a smaller bore than the Quad 4, but a longer stroke. Making it more torquey at low RPM's. The Twin cam also has balance shafts, where the 94 and older Quad 4's dont.
I think the bore on my Quad 4 is 3.63". But the bore is alot larger than the stroke.
Here is an article explaining the differences in the years of all Quad 4 and twin cam motors:
http://www.hotrod.com/techarticles/engi ... index.html
http://www.quad4forums.com/forums/showthread.php?t=4440
The Quad 4, could have been initially a Saab designed motor, it came out shortly after GM purchased Saab, and apparently they were in the process of designing a new L4 motor at the time. Would explain the odd bellhousing (not related even closely to any other GM), and the relatively high HP/L it makes. The motor even has piston squirters, isnt that more of a turbo motor thing, Saab used lots of turbo's.
Also, I sent you the ECM BIN file a year or so ago Ryan, and you said it was totally different from the rest of GM and Caddilac, maybe it is tuned by Saab too?
I think the bore on my Quad 4 is 3.63". But the bore is alot larger than the stroke.
Here is an article explaining the differences in the years of all Quad 4 and twin cam motors:
http://www.hotrod.com/techarticles/engi ... index.html
http://www.quad4forums.com/forums/showthread.php?t=4440
The Quad 4, could have been initially a Saab designed motor, it came out shortly after GM purchased Saab, and apparently they were in the process of designing a new L4 motor at the time. Would explain the odd bellhousing (not related even closely to any other GM), and the relatively high HP/L it makes. The motor even has piston squirters, isnt that more of a turbo motor thing, Saab used lots of turbo's.
Also, I sent you the ECM BIN file a year or so ago Ryan, and you said it was totally different from the rest of GM and Caddilac, maybe it is tuned by Saab too?
Last edited by befarrer on Sat Jun 07, 2008 1:36 am, edited 1 time in total.
Some more info from Quad4Forums:
[quote]A complete teardown analysis of America's first all-new production multivalve engine
By Mike Allen
This article originally apeared in the Feburary 1988 issue of Popular Mechanics.
What’s the no. 1 competitive deficiency of American cars versus import nameplates—particularly Japanese nameplates—today? Opinions vary, but the answer that comes up most often is powertrains.
While Japanese manufacturers have been rushing a veritable tidal wave of new, high-tech powerplants to market, American manufacturers have been struggling to keep pace with engines that belong largely to a bygone era. Good old pushrods and 2-valve combustion chambers may still be fully capable of getting the job done in most applications, but they lack the marketing technoflash of the twin-cam, multivalve layouts of so many competing makes.
Against this background, the new General Motors Quad 4 acquires special importance. Though its design doesn’t really blaze any new trails, it is nevertheless the first domestically produced, mainstream multivalve engine to come down the pike.
And this, in turn, makes it worth a close internal inspection. Designed by the Buick-Olds-Cadillac powertrain division, the Quad 4 began with a clean sheet of paper, unhampered by requirements to use existing tools or components. Design goals for an engine meant to be a bread-and-butter corporate powerplant until the turn of the century included not only specific horsepower, torque, fuel consumption and emissions numbers, but also high reliability. And just as important, it had to be an engine that could be cost competitive.
The idea of four valves per cylinder is far from new. The essence of developing power is to move fuel/air mixture into and exhaust gases out of the cylinder as efficiently as possible, a process that’s largely a function of valve area. There’s a limit to valve area with only two valves, and that’s the diameter of the cylinder, minus a little room for the valve seat. And even as the design approaches this size, there’s a point of diminishing returns: Valve ports too close to the cylinder wall don’t flow well because the wall is in the way. A 4-valve design improves port area and provides the inherent advantage of a central plug location.
The “bangâ€
[quote]A complete teardown analysis of America's first all-new production multivalve engine
By Mike Allen
This article originally apeared in the Feburary 1988 issue of Popular Mechanics.
What’s the no. 1 competitive deficiency of American cars versus import nameplates—particularly Japanese nameplates—today? Opinions vary, but the answer that comes up most often is powertrains.
While Japanese manufacturers have been rushing a veritable tidal wave of new, high-tech powerplants to market, American manufacturers have been struggling to keep pace with engines that belong largely to a bygone era. Good old pushrods and 2-valve combustion chambers may still be fully capable of getting the job done in most applications, but they lack the marketing technoflash of the twin-cam, multivalve layouts of so many competing makes.
Against this background, the new General Motors Quad 4 acquires special importance. Though its design doesn’t really blaze any new trails, it is nevertheless the first domestically produced, mainstream multivalve engine to come down the pike.
And this, in turn, makes it worth a close internal inspection. Designed by the Buick-Olds-Cadillac powertrain division, the Quad 4 began with a clean sheet of paper, unhampered by requirements to use existing tools or components. Design goals for an engine meant to be a bread-and-butter corporate powerplant until the turn of the century included not only specific horsepower, torque, fuel consumption and emissions numbers, but also high reliability. And just as important, it had to be an engine that could be cost competitive.
The idea of four valves per cylinder is far from new. The essence of developing power is to move fuel/air mixture into and exhaust gases out of the cylinder as efficiently as possible, a process that’s largely a function of valve area. There’s a limit to valve area with only two valves, and that’s the diameter of the cylinder, minus a little room for the valve seat. And even as the design approaches this size, there’s a point of diminishing returns: Valve ports too close to the cylinder wall don’t flow well because the wall is in the way. A 4-valve design improves port area and provides the inherent advantage of a central plug location.
The “bangâ€
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I can attest to this, when we built my friend's TC, that head sucked. The ports were small, valves were small, etc. The TDC and Q4 head looked far superior. GM probably did this for other reasons as well as the cracking though, as the TC was made to be a midrange motor. It has generous low end torque, and only runs out to 6200 or so.The Dark Side of Will wrote:IOW, the TC heads don't crack, but don't flow either.
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p8ntman442
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Its been 7 years since I was inside a quad 4, but I'll be dammed if there are piston squirters, cause I didnt put any in my motor. There is an oil slinger, which is just inside the timing chain housing that keeps the oil from pooling around the front main.
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I don't remember any either, but I wasn't going to say anything :salute:p8ntman442 wrote:Its been 7 years since I was inside a quad 4, but I'll be dammed if there are piston squirters, cause I didnt put any in my motor. There is an oil slinger, which is just inside the timing chain housing that keeps the oil from pooling around the front main.
88GT 3.4 DOHC Turbo
Gooch wrote:Way to go douche. You are like a one-man, fiero-destroying machine.
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www.lkqcorp.com sells Ecotecs for like $600 complete, nationwide, letting you spend all your money on boost. You do your own buildup, you'll spend far more, and since tuning boost always has risk of popping the engine, wouldn't it be better to pop something easily replaceable? The Ecotec bottom end is stronger, the head flows better and cracks/warps less, and the only upgrade you might actually need is forged pistons if you go past about 1.8 bar (12 psi) at the TB. If you do go this way, just get one from like a 2001 Cavalier.