kpr 6,491 Posted April 7 Author Report Share Posted April 7 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 6 1 Quote Link to post Share on other sites
ajg193 9,599 Posted April 7 Report Share Posted April 7 How many head gaskets do you go through? Or do you just reuse them? Quote Link to post Share on other sites
kpr 6,491 Posted April 7 Author Report Share Posted April 7 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! 6 Quote Link to post Share on other sites
Valiant 42,006 Posted April 7 Report Share Posted April 7 @kpr what's the story with 7age builds? More volume than the head can flow? Quote Link to post Share on other sites
kpr 6,491 Posted April 7 Author Report Share Posted April 7 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. 2 Quote Link to post Share on other sites
Yowzer 34,760 Posted April 7 Report Share Posted April 7 Or throw $50k at a MRP build for your Instagram 1 1 Quote Link to post Share on other sites
Roman 14,361 Posted April 7 Report Share Posted April 7 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 2 Quote Link to post Share on other sites
kpr 6,491 Posted April 7 Author Report Share Posted April 7 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 2 Quote Link to post Share on other sites
Popular Post Vintage Grumble 25,632 Posted April 7 Popular Post Report Share Posted April 7 You should consider it. 6 2 3 Quote Link to post Share on other sites
cletus 40,334 Posted April 7 Report Share Posted April 7 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 5 Quote Link to post Share on other sites
Vintage Grumble 25,632 Posted April 7 Report Share Posted April 7 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? 1 Quote Link to post Share on other sites
M.H. 6,667 Posted April 7 Report Share Posted April 7 Same with the germans, they carried on racing the 4v engine after it had been replaced by the 5v 1 Quote Link to post Share on other sites
kpr 6,491 Posted April 8 Author Report Share Posted April 8 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. 1 1 Quote Link to post Share on other sites
Spencer 22,678 Posted April 8 Report Share Posted April 8 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. Quote Link to post Share on other sites
Testament 8,484 Posted April 8 Report Share Posted April 8 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? Quote Link to post Share on other sites
kpr 6,491 Posted April 8 Author Report Share Posted April 8 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 1 Quote Link to post Share on other sites
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