When it was introduced in the waning days of the ’80s, the Quad 4 represented a massive step forward for GM. Oldsmobile (along with Batten Engineering and Feuling Engineering) developed the 2.3-liter iron-block, four-valve DOHC aluminum-head powerhouse for the smaller end of its rapidly expanding FWD lineup. Concurrently, a 750hp twin-turbo 2.0 L version made big news in the longtail Aerotech (HRM, Mar. ’87), a full-bodied aerodynamic wonder on a March Indycar chassis that A.J. Foyt piloted to 266-plus mph and the American closed-course speed record at Fort Stockton, Texas.
Production Quad 4s debuted in the ’88 model year. In a day when Oldsmobile’s 307ci V-8 made 180 hp in H.O. trim, a Four with half the displacement and the same horsepower at the flywheel propped everyone’s eyes open with toothpicks. (Base Quad 4s produced 30 hp less.) Why, Ford needed a turbo to get the same power output out of its 2.3L Four. Later, W41-package Olds Calais and Achievas made 190 hp.
Olds went racing with the Quad 4, primarily in IMSA Firehawk and SCCA Showroom Stock, racking up multiple class victories, manufacturers’ class championships in ’89 and from ’91-’93, and promoted its victories aggressively. The IMSA-prepped cars featured non-A/C serpentine belts and other aftermarket tricks, some of which may still be available through the GM Performance Parts catalog and may be adaptable to newer cars; thanks to optimization and a lack of emissions equipment, these engines made roughly 220-230 hp.
Though a success in terms of units built and race victories (and no one ever complained about the power), the 2.3L Quad 4 was bashed by the motoring press for its rough and tumble attitude. As a result, virtually every change made to the Quad 4 has been in the name of improved emissions and greater noise, vibration, and harshness (NVH) suppression. A 1995 redesign decreased bore and increased stroke, bumping displacement to 2.4L; balance shafts smoothed things out, and it had improved lubrication and cooling, plus power output that has stayed at 150 hp despite near-yearly tweaks. The Quad 4 name was dropped when the 2.4L was introduced, and is now referred to as the 2.4L Twin Cam, but for this story we will refer to all engines of this type as Quad 4 and use displacement to differentiate between the two. All inspection was done at Katech Engineering, which worked with Quad 4s in its racing heyday.
Since the Quad 4 has been around for a dozen years, there should be an ample supply in local boneyards. We got together with GM Racing’s Mark McPhail, a strong proponent of front-drive performance, tore a 2.3L and a 2.4L apart, measured the changes, saw what improvements the factory made over time, and figured out what pieces from one engine could work on another. McPhail notes that there were many running changes throughout the engine’s life, and that just because your car is set up a certain way, it doesn’t mean that that parts car you’re pirating from in the yard will have exactly the same ones. “Assume nothing,” he warns.
You can mix and match any number of components (with varying degrees of difficulty), but McPhail feels that the strongest Quad 4 setup would mate a 2.3L head to a 2.4 block, thereby combining the strongest block and the best-flowing head and cams; he would also ditch the balance shafts. He warns that the ’95 engine was a “transitional” engine—a 2.3L with balance shafts—and to avoid it for serious performance upgrades. Also, a single-cam version of the Quad 4 was available in some models; it only lasted a couple of years and should be avoided.
Since it’s not always possible to swap a newer block into an older car (or vice versa, for physical or emissions reasons), we’ve tried to pick out each engine’s strong points so you can choose modifications for your own Quad 4 powered monster. All we need now is an aftermarket to step up and cater to the millions of Quad 4s out there… the GM Performance Parts catalog offers some pieces, but sadly it’s only a fraction of what’s available for popular V-8 applications. Check your GM Performance Parts dealer for availability. Other long-discontinued pieces were once available through the Rocketparts catalog (we saw one dated 1993); these pieces exist somewhere, but you may have to do some digging. Our plan is to get a 2.4L and start playing on the dyno.
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id love to have the real thing.
Oh, you read the article in Hot Rod Magazine too, eh?
Go beyond the "bolt-on".
~tear~
It is so true. the W41 was and still is a beast.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
so why do they say the lubrication is better, when everyone seems to want 2.3 oiling system??
whiteboyz24 wrote:so why do they say the lubrication is better, when everyone seems to want 2.3 oiling system??
Hell if I know. I thought long and hard about that and I don't see any possible way the 2.4 has a better oiling system.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Because thats what GM said to justify making it.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
they said it before problems arose.
Taetsch Z-24 wrote:Because thats what GM said to justify making it.
Chris
That does not make any sense at all. I am pretty sure the reason was to get away from the NVH issues and in general bad rep the 2.3 had.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Quote:
A 1995 redesign decreased bore and increased stroke, bumping displacement to 2.4L; balance shafts smoothed things out, and it had improved lubrication and cooling, plus power output that has stayed at 150 hp despite near-yearly tweaks.
I agree 110% with this statement. People think by changing the pumps, that it will "cure" rod bearing failure... There were reported rod failures with this pump too LoL.
The ONLY reason I would change the pumps is if you raise your rev limiter, to what the older Quads red-lined to, thats it!
All in all, the Quads were and still is a noteworthy engine, especially in the times when racing 4cyls was not as popular as today.
Where in the GMPP catalog does it carry parts? I thought they were discontinued.
What Hot Rod issue was this in, I want to pick one up?
Quad family for life!
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
Reffering to the lubrication system, I beleive they are referring to the more sophisticated oil passages in the 2.4 block over the 2.3. THe 2.3 still had a more powerful pump, and fights better vs aeration in the oil @ high RPM.
My Cav
I give up...
i'm buying a VW those people love trees, so they should love eachother too... "Andy"
The 2.3 pump was also known for breaking teeth off the pump drive gear.
Wade, I meant that is was how GM justified changing it, to others. Like HOT rod mag. if they said, it was because it vibrated to hard in upper RPM, they could just say "de tuned", but that wouldn’t be cool.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
If anyone remembers the scca Q4's, they had a dry sump oil pump. I'll try to find a pic of one. but that was pretty much a fail-proof set-up.
geez what a fancy intake! probably doesn't do a whole lot tho. I like the weight reduction and roll cage tho. how do you know it's for sale? how much he want do you know?
and by the way i think that issue of hot rod mag is up on ebay right now
hey it's the oldsmobile museum. Makes me want a turbocharged LD2.
1988....look at the intake, this was also a prototype LG0..............
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
I have it, somewhere around here...
Go beyond the "bolt-on".
Let me know what month and exact mag title it is.^
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
I know it was Hot Rod. And Street Rodder did a short article too on at least a Highboy with a Quad4 in it, with the coils mounted under-dash with leads fed through the firewall via separaters (One for each plug it seemed), and they were right... without the coil cover in place, it looks like an old Offenhauser. Craziest part of it was how they used an old header fitted with head & TB flanges for an intake, an force-fed it with a Paxton. And for the record, the trans used (oddly) was a Ford C-4 with a custom bellhousing. I would have prefered a 4L60E with one, but that's me.
Go beyond the "bolt-on".
LOL.....this is where I work just 30miles South in the field...........
Quote:
A.J. Foyt piloted to 266-plus mph and the American closed-course speed record at Fort Stockton, Texas.
-I've actually seen several of these races...hella fast cars show up too.
Man...I had this article in my favorites but can't find it right now.
But while I'm here:
Linky - This is a pretty informative article if some havn't seen it.
Also, this thread is a repost.....
