Jump to content
Create New...

Recommended Posts

Posted

Which 2.4 L? GM has two Family II 2.4 L 4-cylinders, the "new" north American 2.39 L engine, primarily used in midsize sedans, and the old 2.4 L, primarily used in light trucks. The former is now available with E85 capability and introduced dual-VVT to the Ecotec lineup. The latter is usually a cast iron SOHC truck engine, but a DOHC aluminum unit is also used in Latin American Vectra's (Astra sedans). Both versions of the old engine are available with E100 capability. Holden is shutting down production of the 2.4 L, as newer versions of the Family II produced in Europe and America replace the old cast-iron block. That means the Opel Antara, Chevrolet Captiva and Thai-built Chevrolet Colorados will all get a new base gasoline engine. The new 4-cylinder from the midsize crossovers is the obvious choice.

Posted

prolly have the same HP approximately. obviously less torque.

now put this engine in the astra...sport? with 6 speeds! lol

it's still what, 6 months+ out... maybe be revealed at la, chi , detroit, or ny?

Posted
prolly have the same HP approximately. obviously less torque.

now put this engine in the astra...sport? with 6 speeds! lol

it's still what, 6 months+ out... maybe be revealed at la, chi , detroit, or ny?

That might work quite nicely....

Posted

Hold on, engines aside, this says we're getting a new `Nox for the 2009 Model Year. That's now. I thought it was for 2010?!

Posted
Hold on, engines aside, this says we're getting a new `Nox for the 2009 Model Year. That's now. I thought it was for 2010?!

and the site is autobloggreen... you think they truely know what they're talking about? ;)

Posted
and the site is autobloggreen... you think they truely know what they're talking about? ;)

Touche. Didn't even think of that. :AH-HA_wink:

Posted (edited)

I just wonder it this engine will take over the 2.2's and 2.4's.... could be the "step up" standard from a 1.4L Turbo...?

if kappa sticks around hopefully it gets this engine sport tuned. I'm guessing it'll be a tad truckish even in the 'nox. ?

could this be the SS engine for the Aveo? lol

I know this engine will cost more in the short run, but it's engines like this that GM will need to push to become truely competitive....like how buick's getting the 3 and 3.6 in the NG laX. or obviously use this motor wisely among divisions...not just EP/Theta Xovers

Edited by loki
Posted (edited)

Personally I don't think the 2.0 DI is just fine. No need to make it bigger. 260hp is plenty and a very civilized 300 hp attainable with a turbo and IC swap.

If they really want to improve on it, I'll keep the 86mm bore as is. No need for a bigger diameter piston it'll only make the engine less knock resistant and may actually reduce boosted performance. If they really want they can stroke it out to about 91mm from the current 86mm. That'll make a 2.1 liter mill which is basically the same size externally. The square 86x86mm bore/stroke configuration is actually suboptimal for extracting the maximum energy from each unit of fuel/air mixture burned. In turbocharged engines, a bore/stroke ratio of about 0.9~0.95 is best.

Same boost, same compression, same turbo will make you about 275hp/275 lb-ft from such a stroked 2.1 liter mill with maximum torque arriving at the same 2000 rpm or so. Not bad really for what is really a crank and rod change.

Edited by dwightlooi
Posted (edited)
I'm thinking that they're talking about a N/A 2.3 DI, not a turbo one.

I'll just drop the 2.2 and 2.4 and use a DI 2.0 making about 170hp and a tad less torque than the 2.4. About 170hp/150lb-ft should be very doable on a 2.0. A slight fuel economy advantage and supply chain simplifications aside, the 86mm stroke 2.0 is also smoother than the 98mm stroke 2.4*.

* Engine stroke is the biggest determinant of engine vibrations in an Inline-4 all else being constant. The 2nd order vibrations in an I4 is created by the fact that the piston at the top of the stroke moves at a different speed compared to those at the bottom of the stroke. This causes a shift in the center of gravity in the system which results in an up-down vibration with a frequency that is 2x the crank speed. The faster the piston speeds the worse the vibration and because a longer stroke engine posts higher piston speeds at any given given rpm they vibrate more vigorously. Dual contra-rotating balancers (aka Lanchester balancers) can mitigate this 2nd order vibration but cannot completely cancel it out because the force profile of the balancers is sinusodial whereas that of the vibrations is not exactly so. (See illustration)

2ndordervibrationsnm3.gif

Edited by dwightlooi
  • 5 weeks later...
  • 2 weeks later...
Posted (edited)
I could handle that.

Chris

Honda engines have traditionally (1990s) been slightly long stroke (for efficiency). More recent ones are VERY long stroke. The D17A in the 2001~2006 Civic for instance has an 75mm bore and 94.4 mm stroke. That is as long stroke as they ever come. In fact, that 94.4mm stroke is more typical of 2.4 liter class 4-potters than a 1.7 liter class engine. And, boy, not being equipped with a pair of balancers that thing shake! It vibrates and groans above 3500 rpm like a bad 2.3 or 2.4 w/o balance shafts.

With the 2007+ Civics they went to an all new (part time Aktinson cycle) R18A design with an 81 mm bore and an 87.3mm stroke. Still no balancers, but this engine shakes no more than the VW 1.8Ts which is to say it's not creamy smooth, but pretty darn civilized for all intents and purposes.

Long stroke engines are popular these days because they extract more energy per drop of fuel just like a longer barrel allows gunpowder more room to do their work in a gun's barrel. Lack of volumetric efficiency at high RPMs due to the smaller valvular area per unit swept volume and higher vibrations are usually deemed acceptable compromises in economy cars. Basically, anytime you go over about 90mm stroke in an I4 you should have balance shafts. But, for cost savings, many econobox engines don't. When you are UNDER 90mm and still have a pair of balancer shafts you are cooking up a super silky powerplant (eg. the GM LNF 2.0 SIDI Turbo; 86mm with balancers).

If you are looking for a poster child of short stroke engines, look no further than Subaru. All their engines are short stroked (Eg. Impreza 2.5L is 99.5mm bore x 79mm stroke). Not so much for high RPM prowess or smoothness; their stuff aren't stratospheric revers and their horizontally opposed arrangement does not incur 1st or 2nd vibrations. They picked pretty short strokes because they have to stuff their H4s and H6s between the front wheel wells. Go any longer in stroke and the engines become too wide!

Edited by dwightlooi

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



×
×
  • Create New...

Hey there, we noticed you're using an ad-blocker. We're a small site that is supported by ads or subscriptions. We rely on these to pay for server costs and vehicle reviews.  Please consider whitelisting us in your ad-blocker, or if you really like what you see, you can pick up one of our subscriptions for just $1.75 a month or $15 a year. It may not seem like a lot, but it goes a long way to help support real, honest content, that isn't generated by an AI bot.

See you out there.

Drew
Editor-in-Chief

Write what you are looking for and press enter or click the search icon to begin your search