Bigport 4age barrys apply here

[kpr]

oh dang  i just noticed  that  the rpm is off in that graph,   which means i forgot to change the rev limiter on the itb tune.   soo  turns out 35 year old stock valve springs are good for 8500rpm haha

[ajg193]

How many head gaskets do you go through? Or do you just reuse them?

[kpr]

Ive got a supply of  genuine head gaskets i never used  from  engine rebuild gasket sets.   but  current one is on round 3.  it stuck to block both times and the top looked mint. so on the head goes! 

[Valiant]

@kpr what's the story with 7age builds? More volume than the head can flow?

[kpr]

not worth it for $$$ imo.   4age can make a decent engine with stock parts.   7a you have to spend some money to make them as strong.  and silly 6 bolt crank.     Just use a 4a and rev it more.

 

[Yowzer]

Or throw $50k at a MRP build for your Instagram

[Roman]

45 minutes ago, Valiant said:

@kpr what's the story with 7age builds? More volume than the head can flow?

What's interesting is that people say 7A has a sluggy rpm band because of a long stroke, but that cant be it. 

7AGE which always seems to make dunga power for some reason:  
81 mm  bore × 85.5 stroke

2ZZ for 1800cc as well, makes 190hp standard
82 mm bore × 85 mm stroke 



 

[kpr]

4age is a dunga also.    so guessing jamming a few more cc's up it doesn't really polish the turd much.    Just pulls the powerband down the rev range. then people failing at using wrong bolt on parts,  means makes no bottom end either. 

maybe i should get a 2zz

[Vintage Grumble]

You should consider it.

[cletus]

Is the 20v head frowned upon in 4age circles? 

 

I haven't had much to do with them apart from a local bogan I went to school with had one in a ratty DX corolla and it went quite hard for what it was. I think it ran high 13s or something? And could do burnouts in 3rd gear which is the true measurement  of hp 

[Vintage Grumble]

17 minutes ago, cletus said:

Is the 20v head frowned upon in 4age circles? 

 

I haven't had much to do with them apart from a local bogan I went to school with had one in a ratty DX corolla and it went quite hard for what it was. I think it ran high 13s or something? And could do burnouts in 3rd gear which is the true measurement  of hp 

All the formula Atlantic stuff was 16v I think? And as far as a I know, they were about as good as 4AGEs got, not sure why 20v were not used?   

[M.H.]

Same with the germans, they carried on racing the 4v engine after it had been replaced by the 5v

[kpr]

20v just the 2ZZ of 4age. Mocked just because.   The 16v does have a far bigger area for the cams to act on especially when go shimless/ shim under bucket. So can run far more aggressive cams in them.        

[Spencer]

Yeah and after that you have to be some kind of race car engineer type to know about the flow through the ports and how that effects combustion chamber mixing and all that. In general though Yamaha tried and eneded up back at 4v per cyl with racing things probably for a reason.

A good blacktop 20v goes hard for what they are though etc.

[Testament]

how does the seat of the pants difference feel in the lower RPM driving round? the tvis intake does make 5?kw more in the low end which doesnt sound like much but is quite a bit when its only making 40kw total at those engine speeds. I'm guessing its not an issue because you dont drive a 4age anything like a truck?

[kpr]

car hasn't made it off the dyno much in the last few months,  not sure if the front wheels still turn or not.     but would say its definitely noticeable.   Changing between my big and small headers effects the 4-5000rpm region,  its  a bit more of a change than what the tvis does.  but is a night and day difference with how the car drives.     As you say if look at it percentage wise is more of a gain than it seems.

Not the best example.   but stockish bt 20v  in fwd chassis  vs  the early bigport with tvis  with good exhaust

[kpr]

Another question thats been around since the beginning of 4age time.    Answer is as expected,   Bluetop cams are a tiny bit better. as tiny bit bigger

 

[ajg193]

Are the dowel pins at the same angular position on both sets of cams?

I've heard that on 4K's they can be close to 10 degrees different from cam to cam

[kpr]

No idea.  Too much mahi to measure 

[rusty360]

I remember we had a ae82 skid car we put a 4age. I remember we reckoned the blue top 40mm crank revd better than the red top 42mm crank, only seat of the pants thou. Then I remember we got a 4ageze and were abit disappointed.