shrike Posted December 6, 2021 Share Posted December 6, 2021 Wondering how much more gains you will notice if the exhaust is the limiting factor 1 Quote Link to comment Share on other sites More sharing options...
Spencer Posted December 6, 2021 Share Posted December 6, 2021 All the gainz are in that exhaust yo someone fax him some 3" tubing and a mig welder. 5 Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted December 6, 2021 Share Posted December 6, 2021 ....and a dumpy muffler. 1 Quote Link to comment Share on other sites More sharing options...
shrike Posted December 6, 2021 Share Posted December 6, 2021 The header/exhaust size discussion I always find interesting and ill admit I am not an expert on it Obviously got to find the balance between torque (via maintaining gas velocity) and flow for the upper RPM (6500+) If it was me I would probably look at getting the header piping as close to the exhaust port size as possible, maybe do a 4 into 1 or a 4 into 2 and then 2.5" to the back. Maybe go 3" if you chuck in some restriction or plan to go turbo later :p @kpr exhaust design he did for the 4age may work well here as well? Do you have to run cats in NZ atm? Quote Link to comment Share on other sites More sharing options...
Roman Posted December 6, 2021 Author Share Posted December 6, 2021 I'm onboard with KPR's school of thought / observations, that beyond the extractors and a short segment after that, the rest of the exhaust is just gas transport. Nothing to do with tuned length, velocity, etc helps. Even on his near stock 20v, removing the exhaust after extractors gave gains. So yes this will get a 3" pipe at some point, haha. Adding a restriction or back pressure never helps. With the porting vs exhaust situation. If you look at the big dick swing K motors with custom heads etc, and they will hugely favor the intake side valves, even at the expense of crappy positioning for exhaust side. So I think porting will help to some extent even if I have a stink exhaust, IF it's allowing a higher amount of fresh air to be captured at higher rpm. I found a chart from someone who ported a 1NZ head. So the maximum lift cams you can get for a 1NZ are 9.5mm lift, that equates to 0.37" on the chart. So if you look at what an unported intake side flows at 9.5mm as is, its about 160cfm. With ported intake side, you now reach 160cfm at about .25" or .26" which is about 6.6mm lift. So instead of having that peak flow value at the impossibly fractionally small amount of time that the cam sits at full lift, you've now broadened it, and this goes all the way down the chain embiggening the flow capability of your cam at all lift values. Which is valuable in this case because I cant actually get any cams bigger than 264 deg 9.5mm lift. On the other hand, it's still possible that this is going to achieve nothing until I've sorted the exhaust. But that's fine too, because exhaust will definitely happen, just not yet. 4 1 Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted December 7, 2021 Share Posted December 7, 2021 18 minutes ago, Roman said: the rest of the exhaust is just gas transport but I do realise that a dumpy will add at least 20 bhp Plus it will add sik soundz bro - possibly even a mean as pulse. 4 Quote Link to comment Share on other sites More sharing options...
deankdx Posted December 7, 2021 Share Posted December 7, 2021 getting chopped by a standard exhaust, stock looking echo is likely a lot more painful than if it's idling like a beast and blast an exhaust tune that the gods can hear though 3 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 7, 2021 Author Share Posted December 7, 2021 Haha yes, I agree. Also it's been enjoyable driving it with the airbox on at night time, because I'm not doorting some poor rural persons kids awake from 3km away haha. So I'm not at all keen on a loud exhaust. Can hopefully keep it reasonably quiet. With my Carina I was surprised how rowdy it wasnt with only straight through mufflers. I'd originally flanged the rear one so I could swap for a chambered muffler to keep it streetable. But didnt need to in the end. See how it goes. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted December 7, 2021 Author Popular Post Share Posted December 7, 2021 19 hours ago, deankdx said: is there any benefit to hooking a dual runner intake for more low end grunt, seeing rods might be on the limit with more revs Speak of the devil Disregard low end grunt, acquire 9000rpm 15 6 4 Quote Link to comment Share on other sites More sharing options...
shrike Posted December 7, 2021 Share Posted December 7, 2021 Hoping your going to fully balance the bottom end including the new stronger clutch to allow for the increased revs? 1 1 Quote Link to comment Share on other sites More sharing options...
Popular Post kpr Posted December 7, 2021 Popular Post Share Posted December 7, 2021 Oosh that fresh chinesium. Ive proven they are good to 10k rpm for at least 5 seconds. so your good to go 4 2 6 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 7, 2021 Author Share Posted December 7, 2021 I'm in a Facebook group chat about Toyota stuff. Obviously these people have no idea who they are dealing with 3 4 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 7, 2021 Author Share Posted December 7, 2021 1 hour ago, shrike said: Hoping your going to fully balance the bottom end including the new stronger clutch to allow for the increased revs? Nah it will be fine* *until it isnt 1 Quote Link to comment Share on other sites More sharing options...
Popular Post kpr Posted December 7, 2021 Popular Post Share Posted December 7, 2021 Ive got you covered with that 10k rpm engine prep also. buy some 10 dollar drug dealer scales. weigh engine parts. butcher said parts with preferred item. so everything within .02gram. then proceed to completely ignore anything that spins, because that cost money to get balanced 8 2 5 Quote Link to comment Share on other sites More sharing options...
shrike Posted December 7, 2021 Share Posted December 7, 2021 7 hours ago, Roman said: Nah it will be fine* *until it isnt 9k is probably manageable (just?) Is it still making power and not peaking at 8500? ( next up dyno chart showing it off a cliff at 8600 ) What do you think the weak link will be next? Rod bolts? Oil system keeping up and bearings letting go? Oil pump failure Clutch? 10k I'm not so sure If serious lol Liked your porting comment assuming it does widen the curve and increase midrange sounds good. Part of me thinks yes the cfm required will increase at lower revs due to less intake restrictions but the exhaust will still limit it. Not sure how much you'll pick up or how much wider to start. Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted December 7, 2021 Share Posted December 7, 2021 12-15,000 RPM is available if you use this gold.... 2 1 1 Quote Link to comment Share on other sites More sharing options...
thegreatestben Posted December 7, 2021 Share Posted December 7, 2021 1 hour ago, yoeddynz said: 12-15,000 RPM is available if you use this gold.... Uncle Rodney Repellant? Quote Link to comment Share on other sites More sharing options...
kpr Posted December 7, 2021 Share Posted December 7, 2021 3 hours ago, shrike said: 9k is probably manageable (just?) Is it still making power and not peaking at 8500? ( next up dyno chart showing it off a cliff at 8600 ) What do you think the weak link will be next? Rod bolts? Oil system keeping up and bearings letting go? Oil pump failure Clutch? 10k I'm not so sure If serious lol Liked your porting comment assuming it does widen the curve and increase midrange sounds good. Part of me thinks yes the cfm required will increase at lower revs due to less intake restrictions but the exhaust will still limit it. Not sure how much you'll pick up or how much wider to start. Judging by his fuel map and having vvt. It should at least hang onto peak power for quite a few more rpm. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted December 7, 2021 Author Popular Post Share Posted December 7, 2021 3 hours ago, shrike said: 9k is probably manageable (just?) Is it still making power and not peaking at 8500? ( next up dyno chart showing it off a cliff at 8600 ) What do you think the weak link will be next? Rod bolts? Oil system keeping up and bearings letting go? Oil pump failure Clutch? 10k I'm not so sure If serious lol Liked your porting comment assuming it does widen the curve and increase midrange sounds good. Part of me thinks yes the cfm required will increase at lower revs due to less intake restrictions but the exhaust will still limit it. Not sure how much you'll pick up or how much wider to start. KPR's 10k rpm comments are in reference to... well... doing 10,000rpm I have no idea what would be the next weakest link. These rods come with ARP bolts and they state they are 9k capable / 600hp rated. It's all just guesses at this stage, there isnt a well established group of people revving Prius engines to 9k haha. It seems Thailand has the most love for turd polishing 1NZ motors. But the language barrier makes things tricky. And yeah the thing with porting the head is that you can increase flow but if you are already at 100% VE then you're not magically going to stuff 30% more air into the engine. But the thing is, fuel table generally indicates where the most airflow happens which relates to peak torque. So even when this starts to nose dive, you're still gaining horsepower. This is fuel map from an old tune on beams motor: The big hump of peak VE is at around 6500-7000rpm then drops off pretty sharply - but still makes best power past that point. (Weird wobbly shit on the graph is thanks to MAP as load source and possibly weird exhaust related harmonics with massive ports) Then look at the prius one If someone showed this to me without the rpm scale, I'd be thinking "Where's the other half of your fuel map? It's not what I would have expected at all. 12 Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted December 7, 2021 Share Posted December 7, 2021 Sitting here, Wednesday morning, having a strong coffee and reading Daves graphs. Sublime. 2 Quote Link to comment Share on other sites More sharing options...
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