Ogre AMG 4g

[isnowi]

If you are looking for NA power/torque, why not consider one of the little brother heads on a std high comp 63, both the 67 and 61 are different to the 63, 67 allegedly runs same cam arrangement (profiles may be differnet but 63 ones will go in) and a smaller combustion chamber 43cc vs 47cc of the 4g63 (numbers may be a little off) i'm told that the difference equates to around .4 of static CR. Also the 4g61 has smaller intake ports, and the same small combustion chamber, which equates to better low end gas velocity, henceforth better low end torque. I don't know about valve sizes, but they are a relatively simple excercise, whereas reducing cc volume and intake port sizes are not so simple.

Incidentally the cross sectional area of a 4g61 head is within a couple of sq mm to the cross sectional area of 4age ST quad throttles, which means dead straight runners..

[fuel]

He is nuts about them and every one he finds for sale he buys.

lol awesome

So the moral of the story Phil, is that the AMG is worth getting or not? Can you build another 4g to be as good or are there parts found only in the AMG one that are worth hunting it down for?

Oh for sure the AMG is worth getting, I convinced dom (corrupt) to get an AMG engine for his E33A Galant. I'm just saying some of that info above is not correct. It has the same bottom end as the normal high compression 4G63 DOHC but the head/manifold/ECU are where the differences are.

[Ogre]

oh man, its getting complicated.....i want maybe around 180-200hp (of course mores a bunus) but be revy, say 8000rpm, but most of all i want it to pull hard to 8000, would rather hav that than an engine that can do 9000rpm but get gutless.If ya get what i mean

You think the AMG is worth the build over doing somthing else N/A, like a different head on a 63 block?

[Spencer]

100hp per litre can be hard/easy to obtain most of this will depend on the head got any pics of ports and combustion chambers? the best way to achieve your goal is to get the head cleaned up, bigger valves would be nice if possible, Itbs on a nice matched manifold, good headers, most compression you can go on 98 and then cam it to suit (all the na basics). If your motor flows well you will need less cam to get the desired hp figure and have a more useable engine ie. wont have to rev the tits off it

[Rusted]

Lub that up. So want a E33A, with gutted when that golant I won off TM folded. 160hp+Lumpier cams+Extractors+ECU=180-200+hp. Awesome.

Still keen set on it for the celeste but I don't want to kill the banker whilst doing it. C needs engine first then the B need P'n'P and then the celeste unless sumthing comes up cheap.

[fuel]

Find a MIVEC 6A12, 200hp standard from a 2L and rev beyond 8000rpm easily. Not to mention they sound awesome when howling away at that revs.

In my opinion the AMG 4G63 probably wouldn't be able to rev beyond 8500rpm easily without serious money thrown towards it. Even if the head setup is really excellent remember the bottom end is still much the same as your SOHC jobbie. The MIVEC 4G92 etc has a much better bore/stroke and rod/stroke combination to allow it to rev to 8200rpm safely.

You are probably familiar with the size (ie the chunkyness) of the rods, crank etc of the 4G63 - compare that to the 6A12 or 4G92 and you'll see why they opted for smaller (and more lightweight) rods.

[Ogre]

so what about a 4g92 then with the same sorta mods, or are they a cunt to convert to RWD?

I dont want somthing insane, just good, and figured that the AMG was a good base to put itbs, some cams and headers, link to get some good power and revs.I still wonna be able to drive it (round town kinda)

[fuel]

4G92 will be able to rev out more sure, but probably wouldn't have the same torque delivery as the 2L. Wouldn't be too much more of a cunt to convert to RWD than the AMG engine.

Stick to the AMG engine, just don't expect it to be a really high revving screamer.

[treggo]

6a12 would rock.

[isnowi]

Valves are already big, bear in mind the 4g63 in its stock standard turbocharged guise, flows absolute mud loads of air, we ran our group A galant with a stock engine on a 14b turbo with 34mm restrictor (meant to be 36mm) and managed to get just over 200hp at all 4 wheels.

4G63's (6 bolt ones, which are the ones with the RWD mounts on the side) also have roller rockers which AFAIK arent the best for massive revs.

Here is a cross section of a stock 4g63 head.

The only thing you may gain for N/A with headwork would be to deshroud the inlet valves a little, if you did much more than that you'd end up sacrificing driveability.

[dwlee]

I am in the process of finding parts for similar 4g63 NA motor. I'll be using a 4g61 head for the smaller ports. The standard valves of the 4g61 are the same size as the 4g63. The chamber volume of the 4g61 is smaller than the 63, but I'll be increase the volume to reduce valve shrouding. The balance shafts will be removed using 4g61 parts. I will replace the rear cam angle sensor with custom hall-effect based system off the inlet cam gear. I am undecided if I will move the water outlet to the front of the head as it will take a bit of experimentation with head gasket water hole sizes to achieve even cylinder temperatures.

Anyway, the inlet port size difference between the 4g63 and 4g61 can be seen in the photos below.

4g63 inlet port

4g61 inlet port

[peteretep]

smaller ports make sense why?

[Spencer]

keeps the air velocity up

[Ogre]

hmmmmmm

good to find ppl that actually know what they are talking about/actually done things.

awsome

[isnowi]

keeps the air velocity up

Higher air velocity equals more responsive engine down low (generally speaking, theres heaps more to it than that) also helps with fuel atomisation, which in turn equals a cleaner more even burn inside the cylinder. Everything has a flow on effect.