Pushrods suck?

[H3llphyre]

GM pushes pushrods -- and reaps savings
Engines allow company to save $800 per unit sold
Performance buffs belittle pushrods as crude and outdated. But pushrods - expected to make up 62 percent of the 5.5 million engines GM will sell in North America this model year - save GM roughly $800 per unit against comparable overhead-cam engines, analysts say.

[Devin Mac]

ok, now lets all go back to chiseling on stone tablets because they're cheaper than computers.

pass me the granite, Feral, i need to reply to J's post...

:thumbsup:

[FATBLOCKMARO]

Originally posted by H3llphyre
GM pushes pushrods -- and reaps savings
Engines allow company to save $800 per unit sold
Performance buffs belittle pushrods as crude and outdated. But pushrods - expected to make up 62 percent of the 5.5 million engines GM will sell in North America this model year - save GM roughly $800 per unit against comparable overhead-cam engines, analysts say.

ILL TELL YOU RIGHT NOW, WORKING IN MY LINE OF BUISSNESS IT IS AT LEAST A 10 TO 1 RATIO ON HEADS THAT BLOW UP OR WARP
FOR EVERY CALL I GET ON A HONDA HEAD BECAUSE IT WHIPED OUT THE TIMING BELT AND BENT ALL THE VALVES YOU HAVE ONE PUSHROD HED REQUEST.... JUST MY .02

[Feral]

Originally posted by FATBLOCKMARO
ILL TELL YOU RIGHT NOW, WORKING IN MY LINE OF BUISSNESS IT IS AT LEAST A 10 TO 1 RATIO ON HEADS THAT BLOW UP OR WARP
FOR EVERY CALL I GET ON A HONDA HEAD BECAUSE IT WHIPED OUT THE TIMING BELT AND BENT ALL THE VALVES YOU HAVE ONE PUSHROD HED REQUEST.... JUST MY .02

It is true ... pushrods are better for people who wont maintain their cars (95% of americans). Basically old pushrods are kind of like the Mr. Fusion from Back to the future. Put any old shit in em ... be it oil, maple syrup, or toothpaste ... and they will keep on trucking.

[Feral]

And for the record ... I think it is awesome that GM has taken the pushrod so far. I still completely believe that DOHC is superior technologically, but the cost doesn't necessarily justify it. However I think GM may be putting their head in the sand ... I mean obviously every other car manufacturer on the planet has found some sort of benefit from DOHC cars ... otherwise they wouldn't be using them ... so maybe GM is just not letting the technology make them more money ?? :eh:

[bren]

Originally posted by Feral
And for the record ... I think it is awesome that GM has taken the pushrod so far. I still completely believe that DOHC is superior technologically, but the cost doesn't necessarily justify it. However I think GM may be putting their head in the sand ... I mean obviously every other car manufacturer on the planet has found some sort of benefit from DOHC cars ... otherwise they wouldn't be using them ... so maybe GM is just not letting the technology make them more money ?? :eh:

Like Jesse said, if Honda whipped out a timing chain and got off the old school belts, wed be all set

[Hullet]

Less moving parts>*

[Devin Mac]

Originally posted by 02CamaroZ28
Less moving parts>*

yeah... great blanket statement to make yourself sound a little uneducated, there, buddy. good work. :thumbsup:

it all depends on what you want out of the setup, and selecting the right tools for the job. just like anything else. you'll flow better numbers out of a OHC setup, but at the sacrifice of cost and complexity. if flat-out performance isn't your goal, then it would be a bad choice. as kurtis stated before, a great majority of people aren't a tenth as concerned with car maintenance as almost anyone on this site.

also, another thing to consider is doing overhead cams on a v-motor is a little more complicated than on an inline 4 or 6. belts get kinda crazy and whatnot, making things even more tricky and less reliable over the long haul. and in an interference-design engine, you're risking slamming valves like cheap hookers when timing belts (or chains... it happens...) go south.

i rip on pushrods a lot, but i know damn well they have their place, so it's all in good fun.

[bren]

Originally posted by 02CamaroZ28
Less moving parts>*

then why arent we all driving rotaries?

[H3llphyre]

Originally posted by Devin Mac
yeah... great blanket statement to make yourself sound a little uneducated, there, buddy. good work. :thumbsup:

it all depends on what you want out of the setup, and selecting the right tools for the job. just like anything else. you'll flow better numbers out of a OHC setup, but at the sacrifice of cost and complexity. if flat-out performance isn't your goal, then it would be a bad choice. as kurtis stated before, a great majority of people aren't a tenth as concerned with car maintenance as almost anyone on this site.

also, another thing to consider is doing overhead cams on a v-motor is a little more complicated than on an inline 4 or 6. belts get kinda crazy and whatnot, making things even more tricky and less reliable over the long haul. and in an interference-design engine, you're risking slamming valves like cheap hookers when timing belts (or chains... it happens...) go south.

i rip on pushrods a lot, but i know damn well they have their place, so it's all in good fun.

Exactly. GM has released a whole new line of DOHC motors, mostly V6es. The thing is, for the 4 door passenger car market, performance isn't the main concern, price is. When you have a fleet vehicle, like the malibu, or the impala, you are MUCH better off from a business standpoint being able to charge $800 less, then to have it perform better. Fleet companies don't give a shit about performance, they want cheap and easy to maintain. A chain driven pushrod motor does that for them. That being said, GM is phasing out a lot of the 3.8 V6's for the new 3.5 DOHC. The also have a 4.4L V6 coming out that is DOHC for the bonneville. Replacing the supercharged 3.8 V6.

My point was, DOHC may be far superior technology for performance, but realistically, if older tech does the same thing, why not use it? Take a look at chrysler's intrepid (3.5L DOHC) and compare it to GM's 3.8L Pushrod... Gets roughly the same gas milage and the 3.5 chrysler makes a few more ponies (20). Is 20hp worth $2000-4000 to you in a 4000lbs vehicle? Remember, it saves GM $800, so the cost to the customer is multiplied.

[Hullet]

Originally posted by bren
then why arent we all driving rotaries?

Because everyone doesnt want to drive the same thing :eh:

[H3llphyre]

Originally posted by bren
then why arent we all driving rotaries?
Because no one has proven yet that a rotary can make decent power, get decent gas milage, and run pretty clean...

[Hullet]

you'll flow better numbers out of a OHC setup

Heres some flow numbers of ported 4.6 DOHC heads

http://www.avengercylinderheads.com/product_info.php?cPath=30&products_id=66

Then heres some LS1 ported heads

http://www.motorsporttech.com/fbody_engine01.asp


Check that out.

[540Malibu]

Originally posted by bren
then why arent we all driving rotaries?

beacuase rotories are more inefficient than a 2 stroke.

[H3llphyre]

Originally posted by 02CamaroZ28
Heres some flow numbers of ported 4.6 DOHC heads

http://www.avengercylinderheads.com/product_info.php?cPath=30&products_id=66

Then heres some LS1 ported heads

http://www.motorsporttech.com/fbody_engine01.asp


Check that out.

Okay, I don't get your point.... The same stage porting (the into stage) the LS1 and 4.6 head flows about the same on the intake, as the exhaust on the 4.6 head flows WAY more. Were you comparing the higher stages of the GM to the basic stage of the ford? Of course, if we want to make a better comparison, lets find some 32V 5.4L heads and compare them to an LS1. You are comparing a motor which has over 1L less displacement. I am willing to bet the 5.4L heads can be ported MUCH more then the 4.6 heads. Again, not sure what your point was?

[H3llphyre]

Originally posted by 540Malibu
beacuase rotories are more inefficient than a 2 stroke.

Speaking of 2 strokes. Spence, did you see on one of the horsepower shows last weekend when they were talking about the Detroit diesels of yesteryear. 4V per cylinder, 2 stroke diesels, with a roots blower AND a turbo. Pretty neat stuff. never knew they existed like that before.

[Hullet]

Originally posted by H3llphyre
Okay, I don't get your point.... The same stage porting (the into stage) the LS1 and 4.6 head flows about the same on the intake, as the exhaust on the 4.6 head flows WAY more. Were you comparing the higher stages of the GM to the basic stage of the ford? Of course, if we want to make a better comparison, lets find some 32V 5.4L heads and compare them to an LS1. You are comparing a motor which has over 1L less displacement. I am willing to bet the 5.4L heads can be ported MUCH more then the 4.6 heads. Again, not sure what your point was?

At 600-650 exhaust lift the LS1 is only behind about 20 max cfm

While on the intake side the LS1 heads blow away the 4.6 heads.
The 4.6 has 293 @800 lift
The LS1 has 300+ @650 lift

Also displacement doesn't matter in these tests, its just the heads being tested off a motor.


EDIT: My point was that OHC engines dont really outlfow pushrod by much, if any.

[H3llphyre]

Originally posted by 02CamaroZ28
At 600-650 exhaust lift the LS1 is only behind about 20 max cfm

While on the intake side the LS1 heads blow away the 4.6 heads.
The 4.6 has 293 @800 lift
The LS1 has 300+ @650 lift

Also displacement doesn't matter in these tests, its just the heads being tested off a motor.


EDIT: My point was that OHC engines dont really outlfow pushrod by much, if any.

Okay, first off... Compare apples to apples. Compare the stage 1 head with the stage 1 head. The exhaust is off by a lot. I was looking at the 550 lift, because, that is more or less the limit of a street motor.

Secondly, yeah, the 4.6 makes 293 @800, but look at around 550 where I said before. The 4.6 levels off around 500... I could care less what flow numbers are beyond 600, unless its a big block head.

Also, the motor DOES matter. Displacement does matter. I know the 5.4L heads are bigger then the 4.6L heads. That's like comparing an inline 4 head to a V8 head. It isn't quite fair... The combustion chamber size WILL limit how much you can port.

[540Malibu]

Originally posted by H3llphyre
Okay, first off... Compare apples to apples. Compare the stage 1 head with the stage 1 head. The exhaust is off by a lot. I was looking at the 550 lift, because, that is more or less the limit of a street motor.

Secondly, yeah, the 4.6 makes 293 @800, but look at around 550 where I said before. The 4.6 levels off around 500... I could care less what flow numbers are beyond 600, unless its a big block head.

Also, the motor DOES matter. Displacement does matter. I know the 5.4L heads are bigger then the 4.6L heads. That's like comparing an inline 4 head to a V8 head. It isn't quite fair... The combustion chamber size WILL limit how much you can port.

as i've stated before, compare your 4 valve heads to GM's 427 and LS6 rectangle ports, the 4 valves lack in flow severely.

[bren]

Originally posted by H3llphyre
Because no one has proven yet that a rotary can make decent power, get decent gas milage, and run pretty clean...

he was saying less moving parts are better, rotaries are kings of that

[Devin Mac]

Originally posted by 02CamaroZ28
At 600-650 exhaust lift the LS1 is only behind about 20 max cfm

While on the intake side the LS1 heads blow away the 4.6 heads.
The 4.6 has 293 @800 lift
The LS1 has 300+ @650 lift

Also displacement doesn't matter in these tests, its just the heads being tested off a motor.


EDIT: My point was that OHC engines dont really outlfow pushrod by much, if any.

i love watching people clutching at straws... :thumbsup:

[Hullet]

Originally posted by H3llphyre
Okay, first off... Compare apples to apples. Compare the stage 1 head with the stage 1 head. The exhaust is off by a lot. I was looking at the 550 lift, because, that is more or less the limit of a street motor.

Secondly, yeah, the 4.6 makes 293 @800, but look at around 550 where I said before. The 4.6 levels off around 500... I could care less what flow numbers are beyond 600, unless its a big block head.

Also, the motor DOES matter. Displacement does matter. I know the 5.4L heads are bigger then the 4.6L heads. That's like comparing an inline 4 head to a V8 head. It isn't quite fair... The combustion chamber size WILL limit how much you can port.

All the information here is valid. I couldnt really fund very much info on the 5.4 head flows numbers. From the little research Ive done so far it seems that there is very little differance in flows numbers to warrant the extra moving parts and extra weight of DOHC.

Also street cams are getting bigger, and alot more drivable. The newest cam out is 242/248 - .608/.612 - 110 lsa

There was a guy at the meet who showed up from Dez's with this cam just installed. Stock heads and full exhaust made over 400 rwhp. The car sounded insane and no fly cutting of the piston was needed.

Mark

[5.0Stang]

http://www.foxlakeracing.com/index.php?src=gendocs&link=Fox%20Lake%20Modular%20Motor%20Heads

Intake: 320cfm@.550 lift
Exhuast 260cfm@.550 lift
4v Cobra heads

[X]

Originally posted by H3llphyre
Okay, I don't get your point.... The same stage porting (the into stage) the LS1 and 4.6 head flows about the same on the intake, as the exhaust on the 4.6 head flows WAY more. Were you comparing the higher stages of the GM to the basic stage of the ford? Of course, if we want to make a better comparison, lets find some 32V 5.4L heads and compare them to an LS1. You are comparing a motor which has over 1L less displacement. I am willing to bet the 5.4L heads can be ported MUCH more then the 4.6 heads. Again, not sure what your point was?
I think the reason they compare the LS1 to the 4.6 and not the 5.4 is due to their usage. The LS1 (F-body) vs 4.6 (Mustang). So using the 5.4 for comparising wouldn't be fair since it is not used in the same league. Does that make sense? :eh:

[383BackInBlack]

wait until the mongoose ls1 heads from AFR come out lol......thats gonna be some freak nasty flowage

[Feral]

This shit belongs in the tech section. Continue your debate guys but keep it constructive please.

Oh and for the record.

#1. Displacement DOES matter because cross sectional area of the cylinder determines how much head area you have to put valves in (duh this is why big blocks rule).

#2. My V6 3.0L stock flows about 220 @ .350 and ported heads will flow about 290-300 @ .500 ... I dunno what's wrong with that 4.6L ...

#3. Rotaries are less effecient than my dog's asshole ... they just happen to come in a very small, light, and elegant package.

[Hullet]

Originally posted by 383BackInBlack
wait until the mongoose ls1 heads from AFR come out lol......thats gonna be some freak nasty flowage

Ohhhh hell yea.

http://www.airflowresearch.com/pages/225cc_mongoose.htm

[Hullet]

Originally posted by 540Malibu
as i've stated before, compare your 4 valve heads to GM's 427 and LS6 rectangle ports, the 4 valves lack in flow severely.

heres some flow numbers for BBC

http://www.airflowresearch.com/pages/357bbc_rh.htm

[Devin Mac]

Originally posted by 02CamaroZ28
heres some flow numbers for BBC

http://www.airflowresearch.com/pages/357bbc_rh.htm

posting up numbers from a site that is trying to sell somehting isn't gonna hold a lot of water in my book.

[383BackInBlack]

they dont call it the BBC for nothin'

:ninja:

[H3llphyre]

Originally posted by DaRam
I think the reason they compare the LS1 to the 4.6 and not the 5.4 is due to their usage. The LS1 (F-body) vs 4.6 (Mustang). So using the 5.4 for comparising wouldn't be fair since it is not used in the same league. Does that make sense? :eh:
Well, the '00 cobra R had a 5.4L DOHC motor... So, it isn't totally unfair. The thing to realize is, as kurtis just said, the size of the cylinder makes a difference. We are comparing DOHC vs Pushrod, not mustang vs camaro.

That being said, I think I will wander off and try to see if I can find any 5.4L heads that are ported... I am more interested in the info then arguing. So, keep posting away people.

[H3llphyre]

Originally posted by 02CamaroZ28
heres some flow numbers for BBC

http://www.airflowresearch.com/pages/357bbc_rh.htm

Yeah, so? Its a big block. I remember what the bigblocks were doing against the Cammer motor from Ford back in the day. Ford owned in the power department there. I would do research on DOHC BB heads, but, they don't really exist.... so, the point is moot.

[Mr Joshua]

If your going to compare ported heads, at least compare something that’s somewhat similar... ala 351w vs. 350 etc...
~J

[383BackInBlack]

Originally posted by H3llphyre
Yeah, so? Its a big block. I remember what the bigblocks were doing against the Cammer motor from Ford back in the day. Ford owned in the power department there. I would do research on DOHC BB heads, but, they don't really exist.... so, the point is moot.

no they dont, but 32 valve BB heads and small block heads to exist :smokin:

and their fuckin sick

http://www.araoengineering.com/Chevy/chevybb.htm

everyone is :owned: by massive flow

[H3llphyre]

Originally posted by 383BackInBlack
no they dont, but 32 valve BB heads and small block heads to exist :smokin:

and their fuckin sick

http://www.araoengineering.com/Chevy/chevybb.htm

everyone is :owned: by massive flow

Yup, I know about them. A tad pricey and it seems like NO one has really got them on their own cars. Only cars that I have found were ones that the company built. Tis one way to get around the pushrod problem... just add more valves. Soon to be, the new vette will have 3V per cylinder with pushrods. Just an alternative route I suppose.

[ianfromma]

Originally posted by H3llphyre
Well, the '00 cobra R had a 5.4L DOHC motor... So, it isn't totally unfair. The thing to realize is, as kurtis just said, the size of the cylinder makes a difference. We are comparing DOHC vs Pushrod, not mustang vs camaro.

That being said, I think I will wander off and try to see if I can find any 5.4L heads that are ported... I am more interested in the info then arguing. So, keep posting away people.

really? how much did the 00 cobra r cost?

hows a cobra r compared to z06?

[H3llphyre]

Originally posted by ianfromma
really? how much did the 00 cobra r cost?

hows a cobra r compared to z06?

cobra R was priced in between the viper and the Z06. It was more or less even (engine performance wise) with both and handled a tad better and stopped WAY better. But, it was an extremely limited production car. Come to think of it, the viper is pretty limited production too. They only make a few thousand every year.

Any more questions? I know you were trying to be a smart ass.

[FATBLOCKMARO]

Originally posted by 383BackInBlack
they dont call it the BBC for nothin'

:ninja:


verry smart man right there

[BackInBlackGTA]

Originally posted by Feral
And for the record ... I think it is awesome that GM has taken the pushrod so far. I still completely believe that DOHC is superior technologically, but the cost doesn't necessarily justify it. However I think GM may be putting their head in the sand ... I mean obviously every other car manufacturer on the planet has found some sort of benefit from DOHC cars ... otherwise they wouldn't be using them ... so maybe GM is just not letting the technology make them more money ?? :eh: ahem NORTHSTAR cough cough...DOHC 32 valve :thumbsup:

[H3llphyre]

Originally posted by BackInBlackGTA
ahem NORTHSTAR cough cough...DOHC 32 valve :thumbsup:

Yeah, and the baby northstar... and all their inline 4's... and the 3.4 DOHC motor... GM makes a LOT of DOHC motors. Their new 3.5L, the new 4.4L... They also have the 3.2L in the CTS. It's not like GM DOESN'T make DOHC motors, they just choose to put the pushrod motors in their FLEET vehicles. You know, the ones that need to be cheap.

[383BackInBlack]

Originally posted by H3llphyre
It's not like GM DOESN'T make DOHC motors, they just choose to put the pushrod motors in their FLEET vehicles. You know, the ones that need to be cheap.

ya, ya know......like the corvette:thumbsup:

[H3llphyre]

Originally posted by 383BackInBlack
ya, ya know......like the corvette:thumbsup:

Haha... the vette does need to stay cheap. Plus, why design a motor from the ground up, when they have a perfectly good design already. I have a feeling that beyond 500hp, they will hit some hurdles... probably why they decided on the 3V setup.

[383BackInBlack]

Originally posted by H3llphyre
Haha... the vette does need to stay cheap. Plus, why design a motor from the ground up, when they have a perfectly good design already. I have a feeling that beyond 500hp, they will hit some hurdles... probably why they decided on the 3V setup.

regular ls1's dont seem to hit any hurdles beyond 500hp

i was just bustin your balls anyways........the vette is awe inspiring BECAUSE it remains so cheap, relative to the kind of vehicle it is.......simply amazing.

[Devin Mac]

Originally posted by 383BackInBlack
regular ls1's dont seem to hit any hurdles beyond 500hp

there is kinda a big difference between factory 500hp and modified 500hp...

[H3llphyre]

Originally posted by Devin Mac
there is kinda a big difference between factory 500hp and modified 500hp...

Indeed... Making 500hp and meeting the federal and state requirements for emissions and gas milage is no easy task. Also, building the rest of the driveline to be able to handle the 500hp, without failing before 200K miles adds to that problem. I know GM can do it, but it starts getting a.) tricky and more importantly b.) expensive.

[ianfromma]

Originally posted by H3llphyre
cobra R was priced in between the viper and the Z06. It was more or less even (engine performance wise) with both and handled a tad better and stopped WAY better. But, it was an extremely limited production car. Come to think of it, the viper is pretty limited production too. They only make a few thousand every year.

Any more questions? I know you were trying to be a smart ass.


actually...i was not. i was curious as to cost, and performance differences. i know the cobra r was more, but i didn't think it was any better.

they compared a cobra r to a 2003 cobra and they were more or less the same. the cobra r stopped slightly faster i think (and was NA), but the price difference is pretty big isn't it?

[H3llphyre]

Originally posted by ianfromma
actually...i was not. i was curious as to cost, and performance differences. i know the cobra r was more, but i didn't think it was any better.

they compared a cobra r to a 2003 cobra and they were more or less the same. the cobra r stopped slightly faster i think (and was NA), but the price difference is pretty big isn't it?

Sorry, i thought you were being facicious... Either way, it cost $55K when they were released... Most people paid more. Of course, they only made 300, so it was a tad exclusive and really a "one off" in my book, because of the low production numbers. Truly a race car though, with no creature comforts and barely an interior.

[Hullet]

Originally posted by H3llphyre
Indeed... Making 500hp and meeting the federal and state requirements for emissions and gas milage is no easy task. Also, building the rest of the driveline to be able to handle the 500hp, without failing before 200K miles adds to that problem. I know GM can do it, but it starts getting a.) tricky and more importantly b.) expensive.

Knowing GM they'd still use the same old 10 bolts that were in all the maros and birds which cant even handle stock power.

Mark

[H3llphyre]

Originally posted by 02CamaroZ28
Knowing GM they'd still use the same old 10 bolts that were in all the maros and birds which cant even handle stock power.

Mark

Eh, the vettes have had Dana rear ends for a while.

[540Malibu]

Originally posted by H3llphyre
Speaking of 2 strokes. Spence, did you see on one of the horsepower shows last weekend when they were talking about the Detroit diesels of yesteryear. 4V per cylinder, 2 stroke diesels, with a roots blower AND a turbo. Pretty neat stuff. never knew they existed like that before.

um yeah, i've rebuilt them, first was an 8v92 (the one they showed) and the other was an 8v71, the 8v71 had no turbo, and which is why they used that blower series for car applications, the 92 series blower has an internal bypass to swich over to the turbo at high rpm, so you dont get the extra superheated blower air, although, if you need the power, both can work at full output at the same time.