So I'm coming here to ask, b/c you are a smart bunch, and you're nice about it How does the 90 degree v6 work? The 60 degree basically has a piston every 60 degrees that fires, correct? And it goes from side to side of the v6 in a firing order 123456, correct? How does the 90 degree work if 90 degrees breaks 360 degrees into 4 segments? I did do some research, and someone said it's the same thing as a v8, with the last 2 pistons sliced off the V. So doesn't that cause a balance issue? Or are 4 pistons 90 degrees, and 2 more are squeezed in between making it 45 degrees in 2 sections?
It doesn't make sense to me, and for the sense of real performance, you'd think tuners would go towards the 60 degree if the 90 degree has performance issues.
No it's the V pattern, 60degs apart or 90degs apart
You're kidding me... How would that produce such a different sound and such? I thought GMs 60 degree engines were completely different from their 90 degree. In a sense their firing order is different, balance, sound, etc?
On any engine, the firing order is determined by the point that a rod journal reaches a given degree of it's rotation. The crankshaft is formed to be as much in balance as is economically possible for a consumer automobile, to keep a continuous rotation and to reduce vibrations which will eventually cause critical engine failure.
Though the Fiero engine firing order is in sequence, 1 thru 6, there was an earlier engine that fired 1, 2, 3, 4, 6, 5. The Fiero engine has been called an even-fire engine while the earlier version has been called an odd-fire. Both 60 degree 2.8's but the odd-fire as I remember was bad about breaking crankshafts. I believe it came in some of the early El Caminos.
The 90* V6 is basically a V8 with two cylinders removed- The original 3.8L V6 had uneven firing, because the 90* angle makes the cylinders fire unevenly with a crank paterend after the V8 crank- with two pistons per throw......Buick/GM finally took care of this by off-seting the crank throws slightly for each pair. The 3800 was one of Wards automotive's best engines for years and years- and when GM finally had to replace it with a DOHC 4V V6(Due to "Public opinion" that 4V engines are "The Future" and Better), that engine had worse performance and poorer MPG compared to that "Old tech PR" 3800. The cylinders banks placed at 60* allows the 3 throw crank to work with even-firing.
Public opinion is wrong- that is why the Corvette, and the GM trucks have better performance AND better MPG than all the competitors......GM sat down(After running that 1990s ZR1 DOHC 4v V8) and compared the two technologies- The PR engine is much lighter & smaller for a given displacement, simpler to manufacture- (and cheaper!). They also burn fuel more efficiently....Do you care if the engine is 1 CI or 500 CI? Not really......You care about the power, how it's delivered, and how much fuel you have to put in. The "secret" high technology is called quench......
Originally posted by cvxjet: The 90* V6 is basically a V8 with two cylinders removed- The original 3.8L V6 had uneven firing, because the 90* angle makes the cylinders fire unevenly with a crank paterend after the V8 crank- with two pistons per throw......Buick/GM finally took care of this by off-seting the crank throws slightly for each pair. The 3800 was one of Wards automotive's best engines for years and years- and when GM finally had to replace it with a DOHC 4V V6(Due to "Public opinion" that 4V engines are "The Future" and Better), that engine had worse performance and poorer MPG compared to that "Old tech PR" 3800. The cylinders banks placed at 60* allows the 3 throw crank to work with even-firing.
Public opinion is wrong- that is why the Corvette, and the GM trucks have better performance AND better MPG than all the competitors......GM sat down(After running that 1990s ZR1 DOHC 4v V8) and compared the two technologies- The PR engine is much lighter & smaller for a given displacement, simpler to manufacture- (and cheaper!). They also burn fuel more efficiently....Do you care if the engine is 1 CI or 500 CI? Not really......You care about the power, how it's delivered, and how much fuel you have to put in. The "secret" high technology is called quench......
The 3800 was not replaced with the High Feature V6 due to "public opinion." Nor are the statements you are making in comparison with the 3800 particularly correct. The 3800 series engines were replaced and eliminated in order to reduce costs after restructuring.
I understand you like the 3800 and don't like DOHC engines for some reason, but please leave out the baseless claims. Public opinion about DOHC versus pushrod technology had pretty much nothing to do with the end of the 3800, nor does a pushrod engine necessarily burn fuel more efficiently than a DOHC engine.
Originally posted by chriswf: You're kidding me... How would that produce such a different sound and such? I thought GMs 60 degree engines were completely different from their 90 degree. In a sense their firing order is different, balance, sound, etc?
Indeed, it only has to do with the angle of separation between the banks which make up the V.
Many variables result in the difference in sound, including displacement, firing order, and exhaust diameters and design.
Indeed, it only has to do with the angle of separation between the banks which make up the V.
Many variables result in the difference in sound, including displacement, firing order, and exhaust diameters and design.
How embarrassing. I swear I read somewhere once (probably on here), where someone said (probably sarcastically), "and that's the angle between the pistons" or something along those lines.
How embarrassing. I swear I read somewhere once (probably on here), where someone said (probably sarcastically), "and that's the angle between the pistons" or something along those lines.
Thanks guys!
Well... it sort of is. The angle between the right side pistons and the left side pistons.
As for why the 3800 went away, I always understood it was for emissions considerations.
How embarrassing. I swear I read somewhere once (probably on here), where someone said (probably sarcastically), "and that's the angle between the pistons" or something along those lines.
Thanks guys!
That would be a correct statement....depending on how you define it. It's the angle between the banks of pistons.
Yup, the 90-degree and 60-degree terms refer to the angle between the two cylinder banks. Since the 90-degree V6 has a wider bank separation angle, it allows more room between the cylinder banks for stuff like superchargers.
That said, the 3800 V6 and the 60-degree V6 are all even-fire engines. Only the original Buick 3.8 was odd-fire. It was literally a Buick V8 missing 2 cylinders.
Since the cylinders on the 3800 are 90 degrees apart, but the firing sequence is every 120 degrees, it requires an "interesting" crankshaft design. But with the 60-degree V6, the cylinder bank angle lines up with the firing sequence, which simplifies crankshaft design. Because of these differences, the engines inherently sound different. The 60-degree V6 tends to have a lively burble, whereas the 90-degree V6 tends to sound "flat".
[This message has been edited by Blacktree (edited 12-14-2015).]
Originally posted by Raydar: Well... it sort of is. The angle between the right side pistons and the left side pistons.
As for why the 3800 went away, I always understood it was for emissions considerations.
The Series III 3800 cars had ULEV classification. The reason it went away is the same reason the 60 degree pushrod V6es went away. Worldwide, the High Feature V6 platform was more widely used, and getting rid of the 3800 and High Value engines means fewer different types of blocks needing to be cast, fewer differences across product lines, etc…
GM working back toward profitability after the bankruptcy/buyout meant reducing costs, so the pushrod V6 engines were phased out.
Dobey, I know you believe that the DOHC 4V engines are handed down from on high.....Truth of the matter is, the Corvette has been beating ALL of the fancy DOHC engined cars in both performance and MPG for basically the last two decades.....You are just processing more air thru a smaller DOHC engine, at the cost of less power down low and a narrower power band. I was all on board the DOHC bandwagon until 1998- the F-bodies got the LS V8 and numerous mags compared them to the Cobra 4.6 DOHC mustang- The F-bodies beat the Cobra mustang in acceleration AND mpg......Things go back and forth from model year to model year, but GM is not relying on "old tech", they are state of the art engines that burn FUEL more efficiently. Maybe you can get the US govt to create an artificial situation by taxing Large-displacment engines like they do in Japan, but like I said, if you are smart you don't care what the HP per CI is, you care about weight, size, power and band width, and MPG......Tell me of a car that can beat a corvette in acceleration AND mpg....And I am talking internal combustion engines, not an electric car with a 200 mile range....You can't do it. As for the 3800, noone would buy the Olds Intrigue because it "Didn't have one of those new-tech "doockey" engines like from overseas" so they made the "Short-star" and the engine was slower in accel and got worse fuel economy....Like you, most of the buying public "KNOWS" that PR engines are no good, but GM kicks everyones azzes with 'em...my ex-GF's tundra is a pig, best it's ever got was 13 mpg.....Even the 4spd auto GM trucks can get 15-18 on the highway.
I would never suggest a PR engine for in-line, small CI designs, but when you get up to V8s, the benefits of the PR engine outweigh the detriments. Zinger engines are fun on a track, but the low-end power of the larger displacement PR engines is far better in day-to-day use, and can be more efficient.
By the way, what kind of engine are you installing in your Fiero? LS4 PR engine- you could have gone with the NS cad- same power, but an extra 100+ pounds of butt-weight.....and worse MPG........
[This message has been edited by cvxjet (edited 12-14-2015).]
Dobey, I know you believe that the DOHC 4V engines are handed down from on high.....Truth of the matter is, the Corvette has been beating ALL of the fancy DOHC engined cars in both performance and MPG for basically the last two decades.....You are just processing more air thru a smaller DOHC engine, at the cost of less power down low and a narrower power band. I was all on board the DOHC bandwagon until 1998- the F-bodies got the LS V8 and numerous mags compared them to the Cobra 4.6 DOHC mustang- The F-bodies beat the Cobra mustang in acceleration AND mpg......Things go back and forth from model year to model year, but GM is not relying on "old tech", they are state of the art engines that burn FUEL more efficiently. Maybe you can get the US govt to create an artificial situation by taxing Large-displacment engines like they do in Japan, but like I said, if you are smart you don't care what the HP per CI is, you care about weight, size, power and band width, and MPG......Tell me of a car that can beat a corvette in acceleration AND mpg....And I am talking internal combustion engines, not an electric car with a 200 mile range....You can't do it. As for the 3800, noone would buy the Olds Intrigue because it "Didn't have one of those new-tech "doockey" engines like from overseas" so they made the "Short-star" and the engine was slower in accel and got worse fuel economy....Like you, most of the buying public "KNOWS" that PR engines are no good, but GM kicks everyones azzes with 'em...my ex-GF's tundra is a pig, best it's ever got was 13 mpg.....Even the 4spd auto GM trucks can get 15-18 on the highway.
I would never suggest a PR engine for in-line, small CI designs, but when you get up to V8s, the benefits of the PR engine outweigh the detriments. Zinger engines are fun on a track, but the low-end power of the larger displacement PR engines is far better in day-to-day use, and can be more efficient.
By the way, what kind of engine are you installing in your Fiero? LS4 PR engine- you could have gone with the NS cad- same power, but an extra 100+ pounds of butt-weight.....and worse MPG........
Originally posted by cvxjet: Dobey, I know you believe that the DOHC 4V engines are handed down from on high.....Truth of the matter is, the Corvette has been beating ALL of the fancy DOHC engined cars in both performance and MPG for basically the last two decades.....You are just processing more air thru a smaller DOHC engine, at the cost of less power down low and a narrower power band. I was all on board the DOHC bandwagon until 1998- the F-bodies got the LS V8 and numerous mags compared them to the Cobra 4.6 DOHC mustang- The F-bodies beat the Cobra mustang in acceleration AND mpg......Things go back and forth from model year to model year, but GM is not relying on "old tech", they are state of the art engines that burn FUEL more efficiently. Maybe you can get the US govt to create an artificial situation by taxing Large-displacment engines like they do in Japan, but like I said, if you are smart you don't care what the HP per CI is, you care about weight, size, power and band width, and MPG......Tell me of a car that can beat a corvette in acceleration AND mpg....And I am talking internal combustion engines, not an electric car with a 200 mile range....You can't do it. As for the 3800, noone would buy the Olds Intrigue because it "Didn't have one of those new-tech "doockey" engines like from overseas" so they made the "Short-star" and the engine was slower in accel and got worse fuel economy....Like you, most of the buying public "KNOWS" that PR engines are no good, but GM kicks everyones azzes with 'em...my ex-GF's tundra is a pig, best it's ever got was 13 mpg.....Even the 4spd auto GM trucks can get 15-18 on the highway.
I would never suggest a PR engine for in-line, small CI designs, but when you get up to V8s, the benefits of the PR engine outweigh the detriments. Zinger engines are fun on a track, but the low-end power of the larger displacement PR engines is far better in day-to-day use, and can be more efficient.
By the way, what kind of engine are you installing in your Fiero? LS4 PR engine- you could have gone with the NS cad- same power, but an extra 100+ pounds of butt-weight.....and worse MPG........
I guess you don't know much, then. You just assume you do. And you really should stop assuming to know how much I do or do not know, or what I prefer.
Nobody would buy the Olds Intrigue, because nobody was buying Oldsmobiles any more. Oldsmobile had been suffering in sales for a long time. So had Pontiac. Why do you think both companies are gone? The pushrod V6 was still around after that even. No, the Shortstar was not the best engine design, but it was gone well before the 3800 went away. The LLT/LFX High Feature 3.6 though makes more power N/A than even the 3800 supercharged engine did, with a broader powerband, and gets better fuel economy.
I never said either DOHC or pushrod was better than the other. What I said is you keep saying nonsense like an uneducated fanboy does. And that's exactly what you are doing. Both types of engines have their place, and overhead cams have been around for over a hundred years, so there's nothing "new" about the technology.
Yes I'm building an LS V8, but it's not going to be a low RPM grunt either. I'm not building it because I think pushrod is better than DOHC, nor am I building it because you do. I'm building it because it's the platform that best matches my goals for the build.
I guess you don't know much, then. You just assume you do. And you really should stop assuming to know how much I do or do not know, or what I prefer.
Nobody would buy the Olds Intrigue, because nobody was buying Oldsmobiles any more. Oldsmobile had been suffering in sales for a long time. So had Pontiac. Why do you think both companies are gone? The pushrod V6 was still around after that even. No, the Shortstar was not the best engine design, but it was gone well before the 3800 went away. The LLT/LFX High Feature 3.6 though makes more power N/A than even the 3800 supercharged engine did, with a broader powerband, and gets better fuel economy.
I never said either DOHC or pushrod was better than the other. What I said is you keep saying nonsense like an uneducated fanboy does. And that's exactly what you are doing. Both types of engines have their place, and overhead cams have been around for over a hundred years, so there's nothing "new" about the technology.
Yes I'm building an LS V8, but it's not going to be a low RPM grunt either. I'm not building it because I think pushrod is better than DOHC, nor am I building it because you do. I'm building it because it's the platform that best matches my goals for the build.
On any engine, the firing order is determined by the point that a rod journal reaches a given degree of it's rotation. The crankshaft is formed to be as much in balance as is economically possible for a consumer automobile, to keep a continuous rotation and to reduce vibrations which will eventually cause critical engine failure.
Though the Fiero engine firing order is in sequence, 1 thru 6, there was an earlier engine that fired 1, 2, 3, 4, 6, 5. The Fiero engine has been called an even-fire engine while the earlier version has been called an odd-fire. Both 60 degree 2.8's but the odd-fire as I remember was bad about breaking crankshafts. I believe it came in some of the early El Caminos.
there was no odd fire 2.8, you're thinking of 4.3's and 3.8's(both buick and chevy), both were based on cut down V8's and have been made as even or odd fire. All gm 60v6's fire 123456. 3800's fire 165432
it would not make sense to have a 60V6 odd fire. GM split the crank throws on 3800's to make them even fire and improve NVH characteristics. you can see the split throws in the picture below.
the downside to this design is reduced crankshaft strength.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
