1g head + magnus v3 cast vs 2g head + SMIM

[vr41mpg]

I am trying to put together a build right now and this is one of the decisions I am facing.

According to Curt Brown's website, the 1G head is recommended for 800+whp and 160+ mph in the 1/4 mile, and the 2G head is for everyone else beneath those power levels. Magnus pretty much confirms this on their website claiming that the 1G head is good if your making "big power." The main feature of their V3 cast intake manifold is the equal flow distribution across the cylinders that is supposedly unmatched in the SMIMs.

What I am wondering is if the equal airflow distribution of the Magnus Intake manifold with the 1g Head will out perform a SMIM with a 2g head. Lets assume we are talking about cars from the 16g to gt35r range.

Before this, it was 1g head + SMIM vs 2g head + SMIM and the 2g head would win the low end battle because of the smaller ports, but is this manifold a game changer?

I would love for Marco, Kiggly, and Curt to respond to this, I would totally be cool.

 

[macaronimike]

Great question. I have the Magnus, but not much to compare it to. Following this thread for EO.

 

[TSiAWD666]

I had my head machined by the same guy who did Andrew Brilliant's head. If you're unfamiliar with his time attack car he has one of the nicest, broadest power bands I've ever seen and still a peak hp of 687 at the wheels. When I asked the machinist if he wanted a 1g or 2g head head he said it didn't matter as when he was done with it either ends up in about the same place. Genius? Talking out of his ass? Dunno. I just know Andrew's results with that machinist's head speak for themselves.

 

[99gst_racer]

So, you're basically asking which head will perform better below 700 HP?
Another 1G vs 2G head thread...?

 

[DSMTyson]

The 2G head is going to be better regardless. UNDER 80ish LBS/MIN.

EDIT: Maybe I should have added this tid bit. ^^^^^

 

[LandSpeed-DSM]

So nice of you to back that up with such a thorough dissertation^

 

[viridionplague]

magnus cast v3 > any smim

larger 1g ports > 2g ports

if you want performance go with the 1g head and the magnus

 

[ShadyGST]

asfdasdsfdsfdsfdsfdsdfhfsghj

 

[e85_4g63]

The 2G head is going to be better regardless.

I'm with this guy.. If you can't search for yourself the reasons the 2g head is superior to the 1g head, then just buy a 1g head and leave the 2g heads for us guys that KNOW why they are better!

 

[viridionplague]

the problem with this comparrison is that the cylinder head selection is application specific.

at lower boost levels the 2g head wins out because the smaller ports and increased air velocity produce better low and mid range power, while the smaller ports dont make as big a difference.

in higher boost applications the smaller ports become more restrictive and once the intake ports are widened to allow better airflow the 1g vs 2g difference becomes minimal.


so now it comes down to the intake manifolds. the casting process the magnus goes through allows for far superior airflow and turbulence characteristics. this is how the magnus can have dead on airflow characteristics across the board instead of variances of up to 10% or so from the smim's.

 

[Bud92gsx]

After extensive porting they both end up about the same.Stock vs stock on a stock car 2g.On a higher rev/power car 1g.

That's all I Have to say.So after this I'm out of the conversation.

 

[bastarddsm]

The 2G head is going to be better regardless.

Better at what? That's a pretty big blanket statement your putting put there.

So nice of you to back that up with such a thorough dissertation^

Exactly, there are two people I would trust on this. Kiggly and Magnus. Neither have 100% hard proof that one is better than the other, and yet one likes 2g stuff, the other likes 1g stuff.

The best part is tons of people with no means to actually test it out, somehow agree that a 2g head is light years better than a 1g head. I can't say that the 1g head has held me back at all.

I'm with this guy.. If you can't search for yourself the reasons the 2g head is superior to the 1g head, then just buy a 1g head and leave the 2g heads for us guys that KNOW why they are better!

LoL why don't you just point us to some legitimate test, showing a 2g head is better. Hell I have a flow bench at my house an some stock 1g heads. bring a 2g head over and we can flow it, measure swirl, and ect until the cows come home. Hell I'd even help pay for dyno time if someone wanted to really get into testing them.

The problem is noone wants to do a real test. A real test, that proves one head is significantly better than the other would involve way to many variables, so the test would be half assed. And then all you could say is: "x head with y cams, and z intake, and t turbo on a motor of c displacement has a xxxxxxx powerband.



Here's the end of the story for all of you playing along... If you start running the turbo hard, THE TURBO SOLELY DETERMINES THE POWERBAND. Cam's, Intakes, Heads have a minimal ( on the order of 10% or less) impact on the power.

There is no reason to go buy a 2g head if you have a 1g or a 1g head if you have a 2g.

The only one that would actually be beneficial is the 4g67, because of its 42cc chambers.. but even then the whole .5pt increase of compression you get, won't effect the power very much at all.

 

[e85_4g63]

LoL why don't you just point us to some legitimate test, showing a 2g head is better. Hell I have a flow bench at my house an some stock 1g heads. bring a 2g head over and we can flow it, measure swirl, and ect until the cows come home.

Like I said, I'm not going to spoon feed anyone, but in my defense I will list a few reasons the 2g head (I feel) is superior to the 1g head. The OP is looking for a head that will work well under 700hp (I assume, and without much port work). The castings on a 2g head are superior (if you search you'll find out more). Also the ports (from the factory) have a much better entry angle (intake side). There are other reasons, but like I said above, buy up all the 1g heads, and leave the 2g heads for us guys that want them. I'm saying (personally) 2g heads are superior to 1g heads, my opinion, and we all know opinions are like a$$holes, everyone's got one... Also, I believe Kiggly, Buschur, and others are using the 2g head. Sure Magnus promotes 1g heads in 1,000whp setups for our applications, as does Curt Brown, but there are reasons behind that also, reasons I'm not interested in discussing.

Also the OP stated about the airflow distribution, good tuning and a good EMS would fix that, no problem. (as proof) Shep didn't have the Magnus cast manifold 5 years ago when he trapped 190+mph. (so obviously the BJ's SMIM, or whichever he was on back then, I don't recall this early in the morning) wasn't holding him back because of airflow distribution. The next point the OP made clear was that he's focusing on turbo with sizes ranging from a 16g (we'll call it 300hp) to a gt35r (we'll call it 650hp). Your not going to trap 160+mph (in a street legal DSM) with a gt35r. I'm not saying it CAN NOT be done, but for the sake of argument, 99% of the members here will never see trap speeds off 160+mph, with a 35r based turbo. I ASSume that 500whp is the imaginary goal of the OP, and that being so, the 2g head is perfect for his setup. Then again, if he already has a 1g head, and a $1,000 to spend on an intake manifold, the Magnus v3 with the 1g head is do-able. To add more, here is a post from Kiggly himself, about the 2g head. On this note, I'm sorry if I offended anyone. I'm not going to argue anymore. I believe the 2g head is better. Like they say "To each his own"

I usually don't jump into threads that are as big of messes as this one, but I have a point to add.

The 2g head does NOT choke at 600hp. It also does not just accentuate midrange at the expense of top end. My race car has a 2g head on it, and with what I wouldn't call an aggressive port job. The port at the flange is stock size, untouched 2g and last season was on stock size valves. It makes about 1100hp at the crank and peak power with the 2.3l is at about 8400rpm. Yeah it is with big cams, but the head is still working in this rpm range.

I believe the 2g head is better overall than the 1g head. The port works well and it has better bracing and structure to keep head gaskets intact.

Kevin

 

[vr41mpg]

Im sorry to cause such a stir. I have done all of the reading about the 1g vs 2g heads, including that post from Kiggly. I also understand that nothing can be proved without actual testing.

My question was more focused on the research and design that has gone into the Magnus V3 manifold. I figured there might be a possibility that the equal flow from this manifold would make up (on the low end) for the inferior castings and entry angle of the 1g head, since if you were to use a 2g head you would have to use a SMIM (which doesn't have the all of the research and design put into it.)


Ideally for the application I intend, Magnus would design a manifold for the 2g head,

 

[joescool2008]

The 1g head is better for now IMO because of the manifold magnus has made. More even airflow distribution is a HUGE plus for us considering i've not seen a DSM with a O2 in each exhaust runner to tune the thing. 2G head is better torque/velocity and for your goal would seem to do better with a 16g but you may start dipping into the benefits of the 1g Head with a 35r. All said is IMO.

 

[99gst_racer]

This will always be one of the greatest debates in the DSM world.

I think the Magnus V3 manifold is an excellent part. With that being said, there are many fabricated manifolds on the market that offer excellent and accurate distribution. The V3 manifold is not the only excellent option for us.

I'm personally a fan of the 2G head. I think the smaller, raised port makes sense for efficient cylinder filling. And Kiggly has shown us that it's not nearly as limited and restricted as many people think. The small block chevy engine and its plethora of cylinder head designs over the past 55 years has shown us that port shape and angle plays a equal if not larger role than port volume.

 

[Bud92gsx]

True Paul.But if someone were to test boh head on a 1g and 2g we could have the solid proof on which head would be better for any application.I dont own a dyno,or i would test the theory.

Sent from droid 4 using forum runner.

 

[99gst_racer]

Test how exactly? I'm not so sure a dyno is the best measurement tool for the job. It would only add variables.

 

[Bud92gsx]

Test.Same car base line with a stock head.Then swap on the other head again same car same mods, same tune.Measure which head produces more low end and top end power.Seems pretty simple to me,But I'm sure I'm forgetting something.

 

[99gst_racer]

Test.Same car base line with a stock head.Then swap on the other head again same car same mods, same tune.Measure which head produces more low end and top end power.Seems pretty simple to me,But I'm sure I'm forgetting something.

Sounds like the Buschur approach to proving/disproving a part. Dyno a baseline with a proper tune. Then swap parts and not retune for parts changes. Then wonder why gains weren't seen. One could use a dyno to show any result he/she wanted because it all boils down to current conditions and tuning. They're a great marketing tool.

If we're wanted to test flow differences, I'd think a flow bench would be more appropriate.

 

[Bud92gsx]

Right bench flow would make sense.But it would also just confirm what we already know about the two heads.

But then again a dyno comparison would also be about the same thing under the right conditions and tune.

So even though you have the dyno comparison.It may not actually lead to any more solid proof than what we already know.And the debate may still rage on.

 

[99gst_racer]

Right bench flow would make sense.But it would also just confirm what we already know about the two heads.

Well, what do we know for sure? Has there ever been a flow bench test done on both heads to test the difference of the ports in stock form and after porting, bowl work, OS valves, etc...?

 

[vr41mpg]

I didnt think the debate was still going on. I thought it was generally accepted that the 2g head was better until you make 800hp+ and then its the 1g that is superior. I just thought that since this manifold was designed for the 1g head, the benefits of this mani might outweigh the benefits of the 2g port angle and casting design.

@99gst_racer... what other manifolds are you speaking of with this equal flow distribution? As far as I know the best one is the HKS Kansai which is twice the price of the Magnus and hard to find

So essentially the battle is between:

good head + better intake manifold

better head + good intake manifold


I know it is probably a negligible difference but I figured there were some engineering-minded people here that would be able to shed some insight into their thoughts on the options.

 

[joescool2008]

Sounds like the Buschur approach to proving/disproving a part. Dyno a baseline with a proper tune. Then swap parts and not retune for parts changes. Then wonder why gains weren't seen. One could use a dyno to show any result he/she wanted because it all boils down to current conditions and tuning. They're a great marketing tool.

If we're wanted to test flow differences, I'd think a flow bench would be more appropriate.

As said in other posts that should be in vendor reviews or a PM when mentioning names of vendors in such a matter. Not a junkie for any certain vendor, never bought anything from the guy, just sayin. Oh the answer to the question is no, the magnus manifold will not give you better velocity than the 2g head in the lower powerband at the power levels you are looking at.

 

[Bud92gsx]

I'm guessing it has never been done back to back.

But if you think about it after extensive porting and so forth. The 2g head should be almost identical flow wise to the 1g head.Forget about the velocity of the 2g head at that point.

Extensive porting of the 1g head should make a very high hp head, with super great flow.

This is just speculation and theory.But logically it makes sense.

Bogus..You say his name and he should come running.Come chime in please.

Just Dick,you say dick I come running."You come where""does your name ever get hard in the morning""you ever make your dog lick your name".