4AGTE Head Setups

[KOV51]

Hi peoples I am building my engine for my AE82 and I am trying to decide on the head designation I should run.

I currently have a smallport 16v head which on advice from an engine builder was to be resined up and hand ported with particular attention paid to the exhaust ports, ccd chambers and staggered HKS cams 264 for inlet and 272 for exhaust, HKS valve springs, HKS cam gears, new over sized valves etc.

Or should I go the path of a rebuilt blacktop 20v head on the engine.

From what I have read and seen it seems as if the 20v blacktop head on a properly built motor makes bulk hp at 20psi which is my target range.

What are peoples experiences and ideas on this as I was always under the impression if you can get away with using a stock part do it as they inevitably are more reliable.

[KOV51]

ps im looking for 250kw approx

[charade_16v]

Gday KOV51,
first of all I am by no means a mechanic...but here is some info i've been told by people who are working on my current 4agte (Big Port) setup here in Sydney:

- Bigport Head is best standard head setup for turbo application
- 20v heads and Quad throttles are built for air velocity, not air volume (Air volume is the aim of any turbo-charged engine), but when put on a 4agte run like ANIMALS, also the 20v head allows the use of a larger turbo because they can rev out further.

Correct me if I am wrong anyone, but as I said this is what i've been told, not my own knowledge.

If you get any more info on the subject KOV51, post it up!

Cheers,
Mark M

[KOV51]

I have spoken to many an engine builder and they say 16v head but the power graphs i see suggest 20v black head is the way to go.

[oldcorollas]

are you building a dyno queen, or drag engine, or circuit engine, or dorifto engine?
each has different requirements

[charade_16v]

I have spoken to many an engine builder and they say 16v head but the power graphs i see suggest 20v black head is the way to go.

Alot of people/mechanics say that to be safe.
remember, someone building your engine doesn't want to see it break.
If you strap on a 20v head, and are thrashing it (I Know i would), it won't be as safe as a 16v.
The 16v revs lower, keeping heat down.
If you want pure power and don't care for reliability, go 20V.

Mick's Motorsport in Sydney is running a few 450hp 4agte bigport 16v setups as follows:
-Copper head gasket
-New Pistons/rings in stock 4agze block
-O-ringed
-Garrett GT3076r (.48 a/r rear housing) at 25-28psi
-FMIC, Microtech, and all the basic add-on goodies
-STOCK cams

If you think about it, those motors are essentially stock, just re-co'd with some reliable parts to put up with bigger boost.
Give Mick a call on 9771 3301, and maybe ask him for some advice, he's done this setup many times.

[oldcorollas]

Alot of people/mechanics say that to be safe.
remember, someone building your engine doesn't want to see it break.
If you strap on a 20v head, and are thrashing it (I Know i would), it won't be as safe as a 16v.
The 16v revs lower, keeping heat down.
If you want pure power and don't care for reliability, go 20V.

that make sno sense?

the engine only revs as far as your foot takes it. why is 20V "less safe"? why does a 16V rev lower?

flow wise, 20V heads can be made to flow more than 16V, but when you are talking large power, then it is more a function of the turbos response.

[charade_16v]

that make sno sense?

the engine only revs as far as your foot takes it. why is 20V "less safe"? why does a 16V rev lower?

flow wise, 20V heads can be made to flow more than 16V, but when you are talking large power, then it is more a function of the turbos response.

Sorry, let me explain what i was trying to say:
The 20v has the potential to rev higher which is it's main advantage when turbocharging (Bigger turbo, more air, lag is less of a problem as you have more time to build up boost).
Higher revs mean more wear on parts, am I wrong in saying that?

Also, i said "Bigport Head is best standard head setup for turbo application"...
AND Correct me if I'm wrong, but i beleive "large power" is actually a by-product of maximum air, fuel and spark...and turbo response will be your last concern if you just want numbers on a dyno.

Best of luck with your endevour for big power KOV51! go for gold.
Cheers,
Mark M

[Starfire]

The ability to rev is more a function of bottom end strength than head design. A good head/cam combo will breathe well enough for it to be worthwhile revving that hard.

The 16v vs 20v argument has many points to consider, but the big 4 are as follows:

In stock form the 16v is shim over bucket, while the 20v is shim under bucket. This means that at high revs/lift/duration it is possible for a 16v to 'spit' a shim, doing considerable damage to the head. If you are planning on revving the fuck out of it (which generally isn't an issue with a boosted engine) you would want to convert a 16v to a shim under bucket arrangement. A kit is available from Toda for about $1200. With your existing cams and expected boost level, 8000 RPM should be both safe, and well suited to your requirements.

The 20v has one more valve than a 16v (rather obvious, but it's worth stating). There is plenty of contention over whether this gives any real benefit. Most people agree that the real advantage that the 20v has over the 16v is that the engine has higher compression, individual throttles, variable cam timing and extractors. The extra valve is mostly for 'wank' factor - don't forget, this engine was built to compete with the wankiest 1600 ever built in Japan - the B16A from Honda.

The 20v has variable cam timing (inlet only) while the 16v does not. Generally, for high powered applications, things like VTEC and VVT (VVTi, VVTLi, etc) are disabled anyway. They're great for a shopping cart that is mildly amusing on the weekend, but just add extra complexity and weight to an engine that is being built purely for performance. The VVT on the silver top is a rather crude on/off arrangement. The VVTi on the black top is somewhat better, but you need a pretty decent aftermarket ECU to use it.

The 16v has larger buckets and a larger cam base circle. This means that it has a larger swept area and can therefore run larger cams without major head modifications than the 20v (you'd probably want to do an underbucket shim conversion as stated earlier).

At the end of the day, in full race trim (naturally aspirated) both the 16v and 20v make almost identical power, which is predominantly limited by their displacement, bore/stroke ratio and the strength of the bottom end.

If I were building a big horsepower 4AGTE, I would start with a bigport head with an underbucket shim conversion. As you already have a smallport with a reasonable amount of work and a decent set of cams in it, I would suggest that you stick with that one, unless of course you are one of those lucky bastards that recently won a division 1 share in the lotto jackpot, in which case go nuts

Cheers,
Terry

[charade_16v]

Awesome write-up Terry!
thanks for clearing up those technical differences.
I still think there is a better way to spend 1200 bucks than a shim-under-bucket conversion kit, but i've never used one so I won't claim to know any better than anyone else.

^^^That's the kind of person you need to be talking to KOV51...someone who offers FACTS about both sides of the argument.

[Starfire]

No problem charade_16v. I try to help when I can (be bothered ).

There are cheaper alternatives to the underbucket kit from Toda - apparently you can use 1ZZ buckets on the 4AG valves, but there is a bit of a trick to it.

The underbucket conversion is really only required if you plan on seeing the high side of 8000 RPM on a regular basis, more than 280 odd degrees of duration or more than 10mm of lift. By the time you've gotten to that point, chances are that you've spent $$$ on things like forged rods and pistons, oversized valves, custom valve seats, monster cams, fancy ECUs, huge injectors, big fuel system and so on. You'd be looking at least in the $10k bracket.

Suddenly the $1200 seems like some pretty cheap insurance

Cheers,
Terry

[KOV51]

Well guys the engine build up so far is as planned:

AE101 4agze Block + Crank (Balanced + linished)
Aftermarket Rods (Spool, Crower, ARGO any ideas????)
Aftermarket Forged Pistons (ACL Race, JE, Wiseco????)
ARP Goodies (Mains, Heads, Flywheel Bolts)
HKS MLS Metal Head gasket
HKS Valve Springs
HKS or Toda Cam Gears
HKS or Toda Cams (264 or 272)
HKS retainers
New Genuine Toyota Oil, Water pumps
Garrett or HKS turbo (HKS GTRS or gt2871 or 2835????)
Autronic SM4 ECU

Thats the setup plan so far I am still open to suggestion and changes. The aim is to have some boost response and not be a lag pig Im thinking full boost by 4000rpm would suit so the power band of 4000 - 8000rpm would be the sweet spot and I guess looking for 200 - 250kw

["Z" UTE]

You can do the shim under bucket for a lot less than Toda setup. The Yaris engine uses buckets that are the same size as the 4A-GE. The difference is that the Yaris buckets have different thickness'. ie. you determine the valve clearance required, and buy the bucket with the thicker/thinner head to achieve that clearance.


cheers Chuck.

[KOV51]

yeah i dont think if i do the 16v head I would go bigger than 272 cams

[30psi 4agte]

Are we talking 250 at the treads or engine?