Roman

Got it more cleaned up and started molesting it with the dremel. I decided that since the valves are small Im gonna need to try deshroud them as best possible. Even if that means increasing chamber volume slightly. Since the direct injector will be gone now, if I can get the hole welded up then it will more than amount to the material lost. So ive been putting a radius on the squish bands. Maybe good for flow but probably bad for combustion goodness. Might reduce knock resistance a bit.ive left the side ones alone except for the exhaust area, but might carry on the profile. in the ports there is a very intentional step on the short side radius, and some naca duct shaped geometry on the lower wall leading up to it. Likely to tumble the air around the corner for good mixing or whatever. However it blended fairly nicely back in to make a more normal curved short side radius. The intake and exhaust ports are remarkably smooth for a factory cast finish. Not really any point doing much to them. There is a huuuuuge amount of taper in the runners, could probably fill in 50% of the port area at the top - but will leave it for now. Im considering cutting the divider shorter but this might be a job for cnc. But again, will run it this way for starters rhen make some incremental improvements/failures later once its running.

That looks so good. Well done

There's no point in a 4-2-1 on a V8, and a 4-1 doesn't achieve the same scavenging effect as a 4 cyl engine. A 4 cyl motor has an evenly spaced 4-3-2-1 (or whatever) firing order. But the v8 firing order means there isnt an even spacing. Which is what gives it that V8 sound rather than sounding like 2 4cyl motors. V8 is more like it fires in pairs quickly together, a gap, then pairs quickly together (shortly after each other) There's still benefit to having a tuned length runner though, you'll probably want them as long as is practical. One benefit of long primaries is that any difference in length between the pipes gets reduced as a % of overall pipe length.

Yeah theres a bunch of mark x at pickapart. Id not be surprised if all of the motors are fucked and thats why they are there. My motor had not that many kms and its so absolutely full of caked up shit. Id not be surprised if all these cars start going extinct around 200,000km. Direct injection without port injection makes for a short lifespan.

Looks like intake valves are ~1mm bigger diameter than a 1NZ, exhaust valves same size. So if it made only exact power per cyl that the 1NZ did, (per cyl, not per litre) that's... 225hp at the wheels. However, it'll have the advantage of considerably more lift, more duration on the cams. And then more space around each valve to flow, and a shorter stroke. So I think it's realistic to expect a bit more than that. Some insanely straight ports! This below is a picture of the bowl/seat arrangement on the intake side. Definitely some room for improvement by blending the bowl cut into the casting a bit better. Then will smooth off the outer cut edge on the very outside too. The short side radius is basically absent / incredibly gross - I guess that's one downside of a super straight and high angled port. Not too sure what to do there, it feels like instead of a curve there it might just be the back side of the seat sticking out to form a square edge. Maybe it is like that to tumble the flow around the corner or something. Will be a tricky spot to get to if I decide to fuck with it. So on the intake side, probably the only "porting" that I will do will be in the combustion chamber / bowl. There's not much point doing anything to the big straight section. But on the exhaust side, the port is TINY, definitely less cross sectional area than a 1NZ. So this will likely benefit from being hogged out as much as I can get away with, without hitting water jacket or whatever. So, probably a good idea to do the exhaust first in case I fuck it up.

Low compression. No aftermarket parts. Stupid scissor cam gear thing. Dunga power as standard. No vvti on the 2500cc Cheap though. Likely all have a zillion km on them though. If cams and valvesprings were available id consider it. Would bolt to j160 is a feather in its cap.

There are some other interesting short stroke contenders, will add in the Alfa 155 DTM motor for interests sake. These are all 2500cc V6 Looks like 2MZFE is the closest in spec to the alfa motor interestingly enough. MZ series motors suck though. Bore size: 4GR: 83mm VQ25HR: 85mm 2MZFE: 87.5mm Alfa: 88mm Stroke length: 4GR: 77mm VQ25HR: 73.3mm 2MZFE: 69.2mm Alfa: 68.3mm

Shit yeah, looks great!

"Buy a newer motor" they said "It'll be fun" they said I'm still cleaning this up, its amazingly grotty on intake, combustion chamber, and the exhaust port. The joys of direct injection! The pistons look okay though, MUCH less shit on them than the prius motor which ran the cooled EGR through it. After seeing it in person I'm a little more optimistic about flowing some air through it though. There's some easy wins in the combustion chamber to deshroud the valves a bit. And the port angle on the intake side looks super sweet! Will take some better pics once I've got some kero and cleaned it up properly.

Yep so the crank could swap. Ideal starting point is the 5GR motor. Its 2500cc with 2GR sized bore and a crazy tiny stroke. But this motor was only available in China for whatever reason.

Not much progress on this as I've been full steam on house stuff, and just too exhausted to do anything car related. However I had a brief respite the other day so started stripping the motor down to try get the heads off. As the next tasks will be fitting stiffer valve springs, and pressing in some plugs for the direct injection ports. It's amazing how much smaller it gets with the stuff off - all of the covers etc dont really contribute any meaningful weight. So this picture here is a reasonably good representation of where the weight is distributed. Definitely a bit lower and further back than beams motor. So, although I'd prefer the car lost some weight from the motor swap instead. This is a reasonable consolation. Something that is on my mind at the moment, that might screw my plans a bit. Is that all of the good things about this motor, are that its a big motor that's been downsized. But there's one major disadvantage to how they've retained the big motor's geometry. The bore spacing is the same as the 2GR, and the valve spacing is the same - this means the 2GR cams will fit. This is great as without beefy cams, this project is dead in the water. But it makes for an interesting design limitation with the head. If we take a look at a 2GR head, with its 94mm bore. You can see that the distance between each pair of intake valves is reasonably spaced, to not be shrouded by the bore, and also not too close together either. So, if you had a blank sheet of paper engine design this is what you'd do. So that's great. But the 4GR motor is keeping that same centers between valves, with a bore that is 11mm smaller. So they have no choice but to shrink the valve diameter to fit inside the bore, as they cant move the valves closer together. So there are these pissy little exhaust valves, and intake valves which are much more shrouded by the bore. With a massive gap in the middle. So, this might be a factor that limits its potential to make power at high rpm, even if the rest of the motor is technically capable. Will give everything a measure up once I've got the heads off. This isnt a deal breaker which will make me choose another engine, but its certainly not ideal either. One potential upside is that these smaller valves will be a bit lighter, which might be helpful. But again, ideally would trade for larger valves that are closer together.

Anyone done this before? I realize it's not cost of time effective compared to welding pipes together. But it's also bloody cool / oldschool method. Not planning on doing it myself, just wondering if anyone out there has had a play with the idea. Basically the concept is that you pack a pipe full of dry (important to be dry...) sand, then heat the area you want to bend with a blowtorch. The sand ensures the pipe doesnt fold or crush. Here are some cool looking sand bent headers from an old timey Grand Prix car popular with bike guys

"Daves weird hobby" could describe literally anything on this forum

Shit yeah! That piston looks rad. How long is it going to take them to do the other 5 though? I'm excited to see how this all comes together, gonna be sweet!

I've bought a Corvette fuel filter, someone mentioned somewhere ages ago that it has an internal FPR, and runs at 60psi. So its an easy way to make a "returnless" setup when there's no provision for an FPR on the rail. After the filter I can just tee off the fuel lines from there to each bank. Will keep the quick release fittings on the fuel rails and make up some AN-6 lines to them. I will need to reroute my fuel hard line a bit though, as I'll have exhaust pretty close to it now. I bought some of the cheap/common dual H bridge boards (L298n) to run the e-throttle motors, but reading further people say that these are quite inefficient (so run hot, and have a big voltage drop to the motors) So might not be as snappy on throttle response as I'd like. However, they're here so I can at least put together a prototype of sorts. Doing some further digging around and people reccomend the mosfet based ones instead, my ECU uses a mosfet based setup. So got these. BTS7960 43A H-bridge Will wire everything up to my ECU and then start writing some code. I will hopefully get everything that the e-throttle module needs into a single CAN frame, maybe two. Then run it on its own canbus network with nothing else on it. Will run the widebands and dash on the other canbus line. Other stuff on to-do list currently: slot flywheel holes This is with Dad, hopefully finished on CNC machine this weekend. Then will bolt it up and take a look at bellhousing situation once I can center the gearbox on the spigot bearing. Sump Pretty close! This version would be good to go, except for that I'd prefer the pan to be a little further back from the swaybar. Will get there. Starter motor This is going to be interesting. As although the 3S flywheel works with the gearbox and crank okay once the PCD is embiggened. The ring gear diameter is a little smaller than the 4GR one. So this means the Mark X starter motor in its normal position wont work. Then the 3S starter position wont work either, because it's normally tucked in on the side of the block up high. But now there's a vee in the way. So I still might need to look at rear mounting a starter. Lots of problems to figure out. Sort of getting there but also feeling like I've hit a bunch of roadblocks at the moment.

Ooohhh awesome to see this getting some love! Gonna be awesome. Anything changed in terms of plans for motor etc for the car now?

Yeah another thing in favour of 4GR is keeping max torque down a bit so a J160 wont explode behind it. However that now seems a bit of a moot point that it'll need a gearbox adapter anyway. However it'll still be nice to use the J160 as it's got good ratios, and, I've already got some to use. I'd rather not go to a bigger heavier box if I can help it.

It's just a number I pulled out of my ass to show a comparison of engine rpm at that piston speed. That was somewhere around max rpm for each of those types of motor. As it seems a more meaningful comparison than the other way around (comparing piston speed at a fixed rpm) And yes I see I labelled it wrong, should be FPM.

Not too sure, havent weighed anything. However gut feeling is that it wont be meaningfully lighter than a 3S setup. Was using this calculator. Was using feet per minute as the units. Sorry if mislabeled it somewhere. https://www.omnicalculator.com/physics/piston-speed RB20 has a nice short stroke and a pretty good rod ratio.

Here's the remix.

HAHAHA This car is the gift that keeps on giving (Go to 11:20 if it doesnt automatically)

I cant flip them the other way because the fuel hose connection onto the fuel rails will hit the bonnet. The problem with standing them up too much more is that it limits me to something like a 20-30mm trumpet on the end. Not sure if that will be enough runner length. Although, the head does have quite a deep port. Key thing here is to try keep making progress towards getting a running motor. Then play around with all the variations on things for about 55 pages later on.

Ahh look at that luxuriously spacious 90 degree Vee! 60 deg vee makes life a bit more tricky for the intake. But, it also gives better room for the exhausts which is sorely needed. Win some lose some. It would be nice to be able to cross the runners across the vee like that V8. But that only works if your throttles are spaced apart at least as far as the ports. Where as my throttles are closer together than the ports. The other pair of throttles turned up today, as well as the H bridge controllers. Looks like I'll have way more room than expected if I want to make them more vertical or push them closer together. I'm desperately trying to avoid raising the motor any more, so the sump situation is taking a fair bit of trial and error. However I've got a setup that now clears the front pulley, the pan nearly fits okay (will push it back a bit further from the swaybar) Then still dipstick hole and oil filter to figure out.

I'm not too sure, but I'll measure it when next in the garage. However I can confirm that it's bloody huge. @anglia4 my ECU actually only accepts a digital input for "clutch", so I'm actually using a general purpose output that then triggers a virtual on/off switch. Reason for doing it this way, is that matching the on/off switch to the clutch engagement point for rev matching or flat shift is super critical. So being able to adjust in software is super awesome. It's not strictly necessarily but it's an absolute life saver. I can add other analog or digital stuff over canbus as well, so not hugely stressed about running out of IO. It's mainly just a case of making sure that all of the mission critical stuff is direct to ECU where possible.

I'm pretty close to final version for throttles I think. I've pushed the pairs a little closer together towards the center of the vee, so hopefully still fits okay. I've added allowance for the injector and added 10mm of straight section to the top of the outside profile, for the silicone joiner to clamp onto. So although it looks a bit derpy on the outside shape, the inside shape means the injectors should be spraying more towards the center of the port rather than onto the walls. So that's nearly one job finished. Only about 50 other things to figure out! Also, I was talking to my Dad about ethrottle situation. He said that I should stop being a little bitch and just make something to control the motors over canbus (Actually he didnt say that, he's a great person) But, yeah, it's not actually all that complex to control a DC motor with a PID routine and an H bridge I guess? Then I could add a feed forward table so it works better than the standard setup. The MaxxECU actually has a way better e-throttle control scheme than Link does, in some good detail here: https://www.maxxecu.com/webhelp/settings-ethrottle-throttle_control.html So I might be able to make it work a bit better than standard. Will get someone smart to review my code though so I'm not gonna kamakaze myself into a wall because I divided by zero or something. However, the ECU would still be accepting all of the inputs, and still be in control of safety shut off features like killing power to the e-throttle relay if it sees a fault. However this does mean that I'm absolutely nuking my ECUs allocation of analog inputs. So if needed I'll try push some more stuff to canbus, and keep critical things direct to ECU.