GM V8 4 Valve?
.
This thread has strayed entirely too far off topic, let's keep it focused on LSx architecture or similar featuring 4 valves.
I'll start.
It'd be great to offer 4 valves, you simply get more air. But for the packaging problems, why not just use forced induction? It's all the same to combustion, more air in regardless of how you do it. By going FI, you can eshew the relative losses compared to using 4Valves by just tailoring the FI to a lower rev band... and since your already higher displacement you can keep running pump gas to prolong avoiding detonation.
This thread has strayed entirely too far off topic, let's keep it focused on LSx architecture or similar featuring 4 valves.
I'll start.
It'd be great to offer 4 valves, you simply get more air. But for the packaging problems, why not just use forced induction? It's all the same to combustion, more air in regardless of how you do it. By going FI, you can eshew the relative losses compared to using 4Valves by just tailoring the FI to a lower rev band... and since your already higher displacement you can keep running pump gas to prolong avoiding detonation.
The one and only point I'm looking to understand is how is this NOT about efficiency? If a head flows better, has the supporting engine attributes to take advantage of these great heads, efficiency is paramount. It gains you everything including better combustion (emissions), throttle response...everything. I'm genuinely interested in hearing other sides...without the political bullshit.
Russ
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
not to *** kiss the mod or anything but every single point he made was spot on there.
in my personal opinion i think if they stuck with the 2 valve setup in the ls series heads just to use something they already use which will save money it would be a better setup for furthering the possibilities of building a cheaper mor epowerful motor.
lets look at the ls1 for example. whats factory compression like 10.1:1 or something? lets say the brought it down to lets say 9.5:1 or so and put an ok sized turbo in it with like 8psi. how much rwhp do you think that would produce on a completely stock ls1? it would be rediculous with the amount of power you could achieve not to mention not a whole lot needs to be changed motor wise. if the went to a 4 valve head i believe it would still be pushrod and use something like the duramax's setup but i think retooling of the machinery and recalibrating of the compuiters and what not just makes it too much of a hassle for GM to bother with.
dont fix it if it ain't broke ya know. i think GM will move to a power adder setup such as a turbo or a blower setup before they moved to using a 4valve setup simply because of the money it would take to mess with it because the parts and everything offered for a differently setup motor would make the cost of building the motor and parts used go up as opposed to making use of whats already there with say a blower or turbo
in my personal opinion i think if they stuck with the 2 valve setup in the ls series heads just to use something they already use which will save money it would be a better setup for furthering the possibilities of building a cheaper mor epowerful motor.
lets look at the ls1 for example. whats factory compression like 10.1:1 or something? lets say the brought it down to lets say 9.5:1 or so and put an ok sized turbo in it with like 8psi. how much rwhp do you think that would produce on a completely stock ls1? it would be rediculous with the amount of power you could achieve not to mention not a whole lot needs to be changed motor wise. if the went to a 4 valve head i believe it would still be pushrod and use something like the duramax's setup but i think retooling of the machinery and recalibrating of the compuiters and what not just makes it too much of a hassle for GM to bother with.
dont fix it if it ain't broke ya know. i think GM will move to a power adder setup such as a turbo or a blower setup before they moved to using a 4valve setup simply because of the money it would take to mess with it because the parts and everything offered for a differently setup motor would make the cost of building the motor and parts used go up as opposed to making use of whats already there with say a blower or turbo
638 bhp (or just over 500 rwhp) with a factory warranty is pretty damn cool in the Zr1...The motor and blower are extremely capable (meaning beyond anything you could ever use on the street, or i guess i meant to say was 'should').
With forced inductions on the LS motors...game over. There's plenty of "LEGENDARY" import motors (2jz,4g63, RB26, blah blah blah) all DOHC realizing the reliability and extreme power capabilities of the LS motors. More and more I'm hearing that chunky LS sound coming out of a Jap or european import. I pulled my motor out for a LS...
Back on subject. I believe it's a matter of output, reliability, efficiency, compactness, and the budget falls inline with a good design like the LS.
Russ
With forced inductions on the LS motors...game over. There's plenty of "LEGENDARY" import motors (2jz,4g63, RB26, blah blah blah) all DOHC realizing the reliability and extreme power capabilities of the LS motors. More and more I'm hearing that chunky LS sound coming out of a Jap or european import. I pulled my motor out for a LS...
Back on subject. I believe it's a matter of output, reliability, efficiency, compactness, and the budget falls inline with a good design like the LS.
Russ
TECH Senior Member
Joined: Jan 2004
Posts: 5,798
Likes: 16
From: St.Charles MO
For V8s though, I prefer the lightweight, compact design of the pushrod engine.
That's foolish to me. I'm tired of arguing the same points. The law has been written and signed by our dimwit President... When they go into effect, Standby.
Douchebag On The Tree
Joined: Nov 2009
Posts: 1,268
Likes: 4
From: Indianapolis, IN
All it takes is someone with a green name to reiterate the points already made by myself and countless others to save this thread. Amazing how that works.
On topic, I don't see the need for FI in at least in the next gen of the LS motors. I think the addition of VVT, direct injection, and possibly OH-4V in some applications being more than enough to stay on top of the competition, let alone right next to them.
I would trade better paper MPG's and peak power for an old dinosaur that doesn't break a sweat getting out of it's own way, all while being more efficient than advertised, any day of the week.
On topic, I don't see the need for FI in at least in the next gen of the LS motors. I think the addition of VVT, direct injection, and possibly OH-4V in some applications being more than enough to stay on top of the competition, let alone right next to them.
I would trade better paper MPG's and peak power for an old dinosaur that doesn't break a sweat getting out of it's own way, all while being more efficient than advertised, any day of the week.
Teching In
Joined: Jun 2010
Posts: 14
Likes: 0
GM should check out the Ford Diesel valvetrain. They can get a pushrod to push on two valves at once, no problem. OHV with 4V. Lightness of an OHV, with the flow of a 4V. And GM knows flow, so you know that would be a sick 4V.
They should really look into that come to think of it! Imagine a 4V LS. I bet it would instantly have like 50% more CFM.
They should really look into that come to think of it! Imagine a 4V LS. I bet it would instantly have like 50% more CFM.
TECH Addict
Joined: Aug 2004
Posts: 2,866
Likes: 4
/\/\/\ i think its more like 20% increased flow. Obviously you need to ensure that rest of the head is up to the taks of flowing enough air.
I personally think this should be taken up by the aftermarket guys. If GM are going to put the money into a 4valve per cylinder LS head then i dont think they would continue the 2 valve option. just my opinion.
Lets start a potition to Nelson Racing, or one of the BIG haftermarket head manufactures and get them to start testing something. I say take one of FORDS Duratec heads as a starting points. they are something pretty special.
Chris.
I personally think this should be taken up by the aftermarket guys. If GM are going to put the money into a 4valve per cylinder LS head then i dont think they would continue the 2 valve option. just my opinion.
Lets start a potition to Nelson Racing, or one of the BIG haftermarket head manufactures and get them to start testing something. I say take one of FORDS Duratec heads as a starting points. they are something pretty special.
Chris.
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The forced induction comment is interesting. You could save the engineering costs and retooling costs of moving to 4 valve heads and just forge the 4.8L motor and throw a supercharger/turbocharger on it. 500hp, 500tq and great fuel economy when your right foot is relaxed. And the smaller displacement will probably get better emissions also.
Douchebag On The Tree
Joined: Nov 2009
Posts: 1,268
Likes: 4
From: Indianapolis, IN
The forced induction comment is interesting. You could save the engineering costs and retooling costs of moving to 4 valve heads and just forge the 4.8L motor and throw a supercharger/turbocharger on it. 500hp, 500tq and great fuel economy when your right foot is relaxed. And the smaller displacement will probably get better emissions also.
The addition of forged motor with boost is gonna add at least 5k to the base price of a vehicle.
Taking that into account with the fact that the 5.5 will most likely be seeing road duty, I don't see 4Vs or FI on an LS engine anytime soon other than further development of LS9-A.
So why can't we have a smaller displacement DI, VVT, N/A or boosted 4.8L, 5.5, and 6.2?
GM already has superchargers available. GM had no problem designing turbo motors for the Sky and Soltice so they know how to do it. A boosted forged 4.8L could make your 450hp and when not in boost get much better city mpg and just as good if not better hwy mpg and be cleaner. With mass production, spread it out over several platforms, normally aspitated and supercharged/turbocharged and the price per vehicle drops quickly.
GM already has superchargers available. GM had no problem designing turbo motors for the Sky and Soltice so they know how to do it. A boosted forged 4.8L could make your 450hp and when not in boost get much better city mpg and just as good if not better hwy mpg and be cleaner. With mass production, spread it out over several platforms, normally aspitated and supercharged/turbocharged and the price per vehicle drops quickly.
v8 with 4v would be awesome to see but i think the ls power plants really dont need it by the fact that they already make good numbers from 2v v8's... and they wouldnt just turbo and sc anymotor by the fact that i takes alot more money for the sc or turbo kits to put on the motors and rite now gm is just wants to pay the rest of there bill out whatever they have left to pay but after that im sure they will do something bad ***
GM could make better use of their 4.6L Northstar powerplant, but for some reason, they don't... I think it's that the LS series has been so successful and the OHV can come in a smaller package. Besides, for "serious" OHC power, multi-valve engines are almost required unless an absolute monster engine is built. That means more money in design and in building an engine. That's the case regardless of size when compared to OHV designs in general.
Cadillac did what? I think Cadillac had positively nothing to do with pioneering OHC, and as far as I can tell, other companies were using it some 20yrs earlier.
Cadillac did what? I think Cadillac had positively nothing to do with pioneering OHC, and as far as I can tell, other companies were using it some 20yrs earlier.
Way back when the 4.6 mod motors first came out I was browsing through the trusty Motorsports catalog and happened to look at the dimensions of the engines. The DOHC 4.6 is nearly exactly the same length as the giant 460...and the 460 without carb turns out to be shorter and narrower.
It amazed me how large the 4.6 DOHC really is. Harder to stuff that big of an engine lower and farther back in the chassis.
It amazed me how large the 4.6 DOHC really is. Harder to stuff that big of an engine lower and farther back in the chassis.
The forced induction comment is interesting. You could save the engineering costs and retooling costs of moving to 4 valve heads and just forge the 4.8L motor and throw a supercharger/turbocharger on it. 500hp, 500tq and great fuel economy when your right foot is relaxed. And the smaller displacement will probably get better emissions also.
GM could even equip this type engine with dual tunes. one for service and performance or flex fuel.
(imagine if vehicle came with such a setup and was equipped to run off e85 with factory calibrations)
all the technology is currently available at GM.
the block could be the ls4 alloy block.
existing 4.8 3.268 stroke crank.
existing 4.8 floating wrist pin con rods with upgraded rod bolts.
Mahle forged version of the existing 4.8 piston and correct rings
existing 243 heads with turbo upgrades (stiffer springs, seals, ls6 valves)
LS9 head gaskets
cast turbo manifold with stainless crossover. stainless dp
improved water pump and cooling system
integrated oil cooler (6.0s came with feature. ran lines from pan to radiator for oil cooler effect. tech alredy available)
make sense to me
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
the northstar program might be just to far along to scrap and honestly im willing to bet if they were so inclined to, it could be takin to a competitive level. but honestly i think cost wise between a new OHC motor being introduced or a 4v setup (both of which im sure GM would find annoying to deal with and make work) i really think they would look at a boosted platform simply because it would easily make more power and it would be relatively cheap AND the aftermarket more than likely would have more support for that type of platform.
i could be wrong but wasnt there some special edition chevy truck that came with a 4.8 and a maggie and could be gotten in either auto or 5spd? im almost positive they made it but everytime i try to think of the name it escapes me. it was named after some guy i know that lol
anyways if theyve techniclly already done it i doubt it would be very hard for them to pick up where they left off and offer that platform in more cars
i could be wrong but wasnt there some special edition chevy truck that came with a 4.8 and a maggie and could be gotten in either auto or 5spd? im almost positive they made it but everytime i try to think of the name it escapes me. it was named after some guy i know that lol
anyways if theyve techniclly already done it i doubt it would be very hard for them to pick up where they left off and offer that platform in more cars
Launching!
Joined: Feb 2010
Posts: 277
Likes: 1
From: Shawnee, OK
true i suppose.
the bottom line there would be that if they were to put money and development into furthering a new engine they would need to make it available in more vehicles but in the case of the northstar how would they market it against the LS series? i just dont see even if it were offered more widely, being picked up and ran with because why would they pic a less developed motor when the aftermarket and everything is already behind the LS series
the bottom line there would be that if they were to put money and development into furthering a new engine they would need to make it available in more vehicles but in the case of the northstar how would they market it against the LS series? i just dont see even if it were offered more widely, being picked up and ran with because why would they pic a less developed motor when the aftermarket and everything is already behind the LS series
the LS series alredy rivals or is close to the SBC in the aftermarket dept. if GM keeps the LS around for as long as the SBC. the LS will no doubt dominate the aftermarket eventually.
IIRC i read in GMHTP Mag. that GM was working on 3 valve LS series pushrod cylinder heads.
the heads valve train kinda looked like the above posted Ford diesel pic posted above. it was a CAD drawing though.
IIRC i read in GMHTP Mag. that GM was working on 3 valve LS series pushrod cylinder heads.
the heads valve train kinda looked like the above posted Ford diesel pic posted above. it was a CAD drawing though.