Roman

Yes you can.has Cusco lsd though

4.3 ratio F series live axle

I found some reasonably good high res images of a 4GR block from front on, top, etc that didnt have too much perspective distortion. (good work camera man) So put these into cad and scaled them to size. One awesome thing is that the flanges for the intake manifold on both sides sit on a flat plane. The factory lower part of the manifold is machined flat as a single piece across the bottom. So if I need to make a manifold that is one single part it's easy. So I can get some rough sort of start on ideas for making an intake. Then I took some measurements from the existing motor in the Carina. it looks as though currently I've got about 440mm from the centreline of the crank up to the top of the motor (With more clearance the further back everything sits) So I'll try work to this for starters. Dark blue line is height limit to try work to. Might be tricky, but also I've probably got a fair bit more room than this in reality. Especially if the engine sits a little further back. Thankfully the valve covers are quite low height and hug the contour of the pulleys reasonably well. Really need to know centers of throttles, and diameter etc before I can get too carried away though.

That box looks way different, bit bigger as well I think. Likely R series like R154 sorta thing. J160 might be a little on the fragile side, but hooning rpm through it rather than a big torque bomb should help in that regard. Although interesting to see that the start motor is indeed on the engine side on that box.

Ring gear is CNC machined into the outside of my existing flywheel. Will be interesting to see how different it is to the 3S flywheel, as it would make life easy if it fits.

Yeah, a few people have mentioned there's a rare manual version. Definitely dont want a big clunker dual mass in there. I'd like to be able to use my J160 boxes, but then if I could sell 3 J160s and get one box that bolts straight up... Maybe worth it!

Haha, not mid mount but it should hopefully naturally want to sit reasonably far back. It will be interesting to see what this will end up weighing.

Here's a list of the major problems I think I need to address, but dont have 100% answers for yet. Engine fitment in the bay Obviously I dont have a way to confirm this yet, but it looks like the engine mounts should sit on the Carina crossmember nicely, and the rear sump position should have plenty of room behind the standard carina crossmember. The only picture I can find of an empty engine bay is ths one from about 65 million years ago when I first painted the bay. But you can see there's a generous amount of room behind the cross member, and both sides of the firewall beside the tunnel slope back at about a 45 deg angle - because these cars came fitted with motors that ran the exhaust down either side of the motor, depending what motor. The steering column looks like a problem here, but I dont think it was fitted at the correct angle in this pic. And I think this pic is misleading about the angle. Hopefully it's not an issue! It's looking like I might be able to sneak the 3 exhaust pipes right beside it hugging the motor, but we will see. Mounting engine to J160 So I found a single forum post, saying that someone tried this with a 4GR motor and it was reasonably successful. They confirmed that the bellhousing pattern is the same as a 2GR, because the 2GR is very commonly bolted up into MR2s as a 3SGTE substitute. The main problem is that the Altezza box usually bolts the starter motor to the engine side, very close to the block. But now that the block is a vee, the starter motor wants to exist where the engine does. o it looks like I might need to find a starter motor that spins the other way, and mounts from the other side. Easy enough though, as that's how all of the east-west motors run things. Or the auto 4GR starter motor will work fine like that. Clutch and flywheel It looks like a 3S flywheel doesnt work. They both have an 8 bolt crank but maybe the PCD is different. Either way, my Altezza flywheel wont work because if I'm starting the engine from the other side, the teeth need to be cut the other way. Good news is that a 1MZ (earlier toyota v6) flywheel does in fact work. There are a few light weight aftermarket options available. Since there is normally a spigot bearing for the J160 box, which isnt present on the FWD boxes. And the mounting face of the dual mass altezza flywheel is reasonably far from the motor. I might need to look at some sort of solution that maybe machines down the face of the bellhousing, or spaces out the flywheel or something. Otherwise the nose of the input shaft will not be supported, and there might not be enough spline engagement. Thankfully I've already got 2 j160 bellhousings off the boxes, so I can easily do some mockups and so on to figure things out. Will 2GR cams fit? Signs are pointing to "mostly sure yes" I have confirmed that someone has fitted a 4GR crank into a 2GR block. Then also confirmed that the spacing between bores is the same for both motors. So it's looking pretty good for being a direct swap over, but I'll obviously need to try confirm this before I get too carried away with everything else. As if the 2GR cams dont fit, I'm basically dead in the water for my rpm goals. Intake manifold / converting to port injection Interestingly the 3.5 litre engine has both direct injection, and port injection. So this motor has a very short port divider, deep in the port. In the toyota documentation it states that the rationale for this, is to minimize the port area that can be affected by wall wetting from the port injection. Because it fits the injector above the port, the port is angled down a bit closer to horizontal. It's a bit more of a classic looking 4 valve intake port: However, the 4GR motor is direct injection only. So there is no port injector on top - So they run a much steeper port angle. Also, the motor runs a TVIS style system where it closes off one valve at lower rpm for better mixing or whatever. (not shown) Super steep ports! So I'll be mounting injectors much further up the intake tract. But I think I will keep the port divider nice and long, and print an intake which continues this further up closer to the throttles. Here's a cross section of what the intake ports look like. How about that nearly non existent short side radius. Bloody good. I found a scanned copy of the intake gasket, and based on the bore to bore center of this motor (105.5mm) I scaled the drawing. This wont be 100% accurate as the gasket usually sits a 1mm or 2 inside of the mating surfaces. But from an initial eyeballing the port has equivalent cross sectional area to about a 52mm circle. So we can likely say the actual port area will want something like a 48mm or 50mm throttle. So to solve 2 problems at once, Triumph comes to the rescue (maybe) The Triumph Tiger 1200cc motor is a 3 cylinder engine with a 90mm bore. So the port spacing should be fairly equivilent to this motor hopefully. It would be awesome to be able to run a twin e-throttle setup, and avoid the need for balance bars, cables, and all of that stuff. It would also provide a convenient place to mount some injectors, and the fuel rails. The Triumph motor makes 140 horsepower with 3 cylinders, so with two of them it will have easily the injector capacity for 300hp or whatever. But maybe not, because when you are doing mega rpm the deadtime of the injector becomes a major element of determining the injector size needed. But we shall see. One problem with any off the shelf setup like this, is going to be that there isnt a mirror image version of the throttles available. But, that might work out alright so there's better clearance between the e-throttle motors in the engine's V. (thats what she said. or something.) My next problem is that my ECU cant actually control 2x ethrottle units. There is a canbus extender that allows e-throttle control to ECUs that dont have it - But I cant use the onboard H-bridge as well as the external one, for whatever reason. I'd need a G4X ECU in order to do that, which is quite a lot of extra money. So, will do some more head scratching on this one. That's all for now. Hopefully pick up the motor later in the week once the storm has settled a bit.

Yeah I agree with that. The echo has been so much fun that it's been a 100% distraction. And thats been absolutely awesome, I've loved it. Not only that, a lot of the tricks I've found out (such as adapting bike throttles, finally figuring out how to 3d print manifolds effectively, how to make shitty carbon stuff) Will all come in handy. Going to be cool.

So a basic overview of where I'm currently at, and where I hope to be. My Carina has been running a beams 3SGE motor for many many many many years. I think I bought the redtop motor for it in 2005! And it's been awesome. I've also done heaps of driving in the car and I've done my best to keep it as a nice weekend car and a bit of an all rounder. It's been great! However, as time has marched on the state of Altezza engines, and Altezza owners, has deteriorated considerably. After having the echo project, where it was like working on a brand new engine. I decided I wanted a new motor for the carina that was a bit newer, still common/cheap, and where the average kms isnt hovering around the 300,000km mark. So, for that and a variety of nerdy reasons I've outlined in the tail end of my beams 3SGE thread. Time for a 2500cc 4GR V6. Exciting! This is the motor that I've bought, but not picked up yet. Unlike the other GR motors this one is designed from day dot to plonk into an upright FR configuration. Also, it somewhat bolts onto a 3SGE bellhousing pattern, so I can use my existing J160 gearboxes with it.

Long time no post. I've had this car for a long time, so it's not really a new project. However, it's been dormant for the last few years while I've been mulling over options for a new engine. New motor Criteria: -Capable of big rpm -less weight than beams motor -newer motor / alloy block -Be nice if it bolts to a J160 without adapter These are some of the engine options I've been going back and forth between: 1NZFXE NA Probably a bit too slow for a ~950kg rwd car... But maybe alright with a diff ratio change. Would definitely be the lightest option. Lots of room for activities with intake etc! 1NZFE+turbo This would be great because it would achieve nearly everything I want (lots of rpm, a power increase, less weight) However I do prefer NA motors for ease of working on but also tuning is more fun I think. This wont bolt up to a J160 directly, so that's a headache not present with some other options. Also the exhaust runs down the drivers side which is a bit annoying. Bike motor I am keen to do a bike motor project, but, I think this isnt the right car for it. Too big/heavy. But how cool are bike motors? Built with amazing ports, mega rpm, and sequential box that can shift near instantly. Bloody good. It just really excites me to buy a 10 second bike and turn it into a 14 second car haha. Have you considered a 2ZZ Yes, yes I have. Pluses to this are that it's lighter than a beams motor, VTEC! and built from the ground up for lots of rpm. Good power potential. Downsides - motors are hard to find, that arent either clapped out from high km, or needing to buy a whole car to get an engine. Needs a bellhousing adapter, exhaust runs down the drivers side (steering column/brake master cyl annoyances) Niteparts is currently working on fitting a 2ZZ to AE86, really excited to see how it turns out. 2ARFXE or 2ARFE This is a big late model 2.5 liter 4cyl motor that's gaining popularity for modding. The FXE version uses the same tricks as the Echo motor, however, the factory cams have some pretty decent lift and duration unlike the 1NZ. So it looks like the popular cheapish option is to use a second intake cam in the exhaust side, then you've got 270deg cams with 11mm lift. Pretty sweet. Downsides? It's a tall bugger. I'm definitely not wanting to do anything that requires cutting the bonnet. Might not fit. Also, it would be weight neutral rather than losing any weight from front of the car which was one of the goals. Since it has quite a long stroke, it probably cant rev as high as I'd like. I'm more concerned about engine sound/feel/revvyness rather than outright power. It's a good option, especially if it can bolt to a 3S bellhousing - but being rpm limited to 7500 or something. Blargh! So, yeah. Those were the options I've been considering and trying to decide between. However while browsing through Dodson's trademe site for cheap big block 4 cyl FXE engines I spotted something interesting that I'd not considered... A new challenger appears! 4GRFSE Now this is a bit of a WTF option but hear me out. The 4GR's big brother, the 2GR. Is a 3.5 liter V6 that is commonly swapped into MR2s etc, because can bolt up to a 3S bellhousing. However most of the 3.5 liter versions suit having the motor tipped over for east/west config. I think you need to buy a Lexus motor to get the RWD config motor, and uhhh yeah. Lexus tax. The 4GR is the 2.5 liter direct injection V6 from a Toyota Mark X, which is setup for FR config. It's got a rear mounted sump, which by eyeball should easily fit behind Carina crossmember. Also, they're cheap and readily available as Mark X are a fairly common car. Why not 2GR for an extra liter of displacement? Well, the 2GR makes good power but it's got a big bore, big stroke, and will be rpm limited on factory pistons to less RPM than I'm willing to settle for. The short stroke and smaller bore of the 4GR motor means pistons/rods are lighter and the mean piston speed is considerably lower at a given rpm. To be honest I've never really considered a V6 because I think a 4 cyl motor is more in keeping with the spirit of the car. But when you look at the numbers, there's no way to get an off the shelf 4cyl motor that has a big enough bore and short enough stroke for mega rpm. Even the tiny 1NZ has rpm disadvantages compared to it. Another interesting aspect, is that since this motor is DI only from factory. It doesn't have any injectors in the ports, which usually seem to result in more angle on the port. In this case the DI injectors are mounted below the intake ports, so it's got STEEP intake ports. Another good sign for high rpm. The downside is that as per every DI only engine, the intake ports clog up with shit. Solved by converting back to regular injection. Still thinking "why a V6?" (boooo) I think it's going to be possible to get a semi reliable 10k rpm from this motor. Honestly how many engines are capable of running to 10k? How good is that. If these numbers stacked up the same way with a 4cyl motor, I'd use that. But they dont. Also to remove any doubt of this motors absolute peak performance potential this son of a bitch has a modern day TVIS equivalent. shit a brick. I've come to realize from the echo that revving the absolute bejesus out of something puts a smile on your face for longer than outright power does. This motor, the bottom end at least, should be 10k rpm capable with considerably less stress on the motor than any other option from the Toyota stable that I can see. Here's some graphs, because, well, it's my thread and thats how it goes. Bore size 4GR is about middle of the range for bore size, which is a good indicator of piston weight. Keeping in mind that piston area goes up non linear to diameter, so only a few mm more can mean a considerably heavier piston. pistons will definitely be a a fair chunk lighter than 2AR or 2GR options. Stroke length 4GR has got by FAR the shortest stroke out of options. Nearly 8mm shorter stroke than a 1NZ. Considerably shorter stroke than a 2ZZ, which is a pretty good benchmark for a high rpm capable engine. God damn delicious! Compression ratio Lower than some of the options, nothing beats the 1NZ! However 12:1 is still awesome, the fact it's a non hybrid factory engine with CR that high is great. Rod length (Thats what she said) 2AR has the longest rod, but it's also got the longest stroke. Apparently the 2GR and 4GR have the same rod length, which would mean the 4GR block must be more compact. Good news for keeping the engine height down a little. Nearly 10mm longer rod than a 2ZZ. Rod/stroke ratio The highest the rod/stroke ratio number is, the straighter the rod stays when travelling up and down the bore. So less side loading on the bore. This is generally considered a good thing for high rpm, and it also changes how long the piston dwells at TDC and BDC. (higher number favorable for more rpm) An S2000 has a rod ratio of 1.82:1 Having a 1.92 rod ratio is god damn glorious for high rpm from a factory engine. Mean piston speed Rather than picking an RPM and listing the mean piston speeds, I've chosen a mean piston speed (4500 feet per second) then shown how high each motor can rev when reaching this number. The 4GR does wees over everything else. Keep in mind that I'm revving 1NZ to 9k currently, which would be same piston speed as nearly 10k with the 4GR. (4GR will have a heavier piston though to be fair) Sooooo yeah. I think a 9500-10,000rpm motor should be doable, as there are big cams available. If so, it will be friggen wild. Well, there are big cam and stiff valve spring options available for the 2GR - but I'm not yet sure if these will fit the 4GR. Looking at pictures of the head gaskets, it looks like the 4GR has the same bore spacing but just bigger gaps between cyls. I've bought a motor to test fit everything initially. It's not much of a gamble as they're reasonably cheap. I'm hoping things will all work out, but there could be some issues yet. Good thing I got some practice using a hand drill to modify engine blocks with the 1NZ. Might need these skills. Here's a few pics of the next modern Toyota FE motor I'm planning to turd polish into oblivion. I'm super excited about this! There's still a zillion reasons why it might not work out, or something doesnt fit, or blah blah blah. But if it all works how I'm hoping, it's going to be cool as hell.

Hi, starting a new chat thread as feels like a fresh start on this car again.

It's been bloody awesome fun alright. But also it's a bit tapped out now. You cant get any 1NZ cams bigger than 264 deg, and there were only "admin" sorta jobs left to do like sort out an air filter or tidy it up. Things which made the car nicer but fundamentally didnt alter the recipe any further. I'm actually really happy to end a project on a high note. It seems a lot of projects end up being sad to look back on if they ended when a car was crashed, or motor blew up, or sold to have kids or whatever. This has just been grin factor 10 nearly all the way through. Also I've managed to infect some other people with the concept of vitz pesting, and the parts from this car are going to be used in some cool setups. Also worth noting that back when this car was standard I came incredibly close to just giving it away as I no longer used it. What an absolute adventure it's been on, at the tail end of it's life instead. How good!

Ahh man there's always something eh! Drive from last shakedown looked good, stoked to see it's making steady improvements. Would love to check out your car one day, love it.

Thanks everyone who's helped me out with this project, I think it has been the most fun and satisfying project I have ever worked on. However, for a variety of reasons it's come time to sell up. I've tried to come up with a price at which I could pass this on to someone, and keep it going as-is but there are a few problems. Firstly I need my ECU and wideband etc back for the Carina. Selling the car with ECU then buying new ECU doesnt really work, because I'm looking at a ~$3k replacement cost. Then I've painted myself into a corner with the e-throttle setup, as I cant just chuck a cheap ECU at it to sell. Then, the shell that this project has been based on is a bit rough. So seems unfair to sell it with existing wof/reg but then no cert. Also not keen on selling someone my wiring under the dash. Haha. It's reliable but its just messy. If someone wanted an awesome vitz project, would make sense to reshell it into a good condition Vitz RS. However, I'm super looking forward to getting back to the Carina eventually now. I've been in limbo with that car for a long time not knowing what to do, and this car has filled in that gap and been friggen amazing. I wont have any money to do anything meaningful with it for a long time, but I've at least bought an engine block before I've run myself broke with house stuff. So I can do some scheming and 3d printing some prototype intake parts etc while I'm poor. Here's a link to the post parting it out if anyone's interested in some bits. Thanks for tolerating my rambling for 75 pages about Toyota Echo stuff. Jesus.

Yep your car definitely came to mind! The small mazda V6s are great. It's been brought to my attention that the Nissan VQ25HR motor is pretty wild, its like a more extreme version of whats good about the 4GR. 2.5 litre but a little bigger bore, shorter stroke again by a few mm, and 7500rpm redline factory. The only downside is that it only has a 10something to 1 compression ratio pistons which is a bit of a bummer. Well, that and its a Nissan motor, which is a bridge too far for this car haha. But it also hits that same sweet spot for being rev capable, aftermarket support from the bigger engines of same family (350Z etc) and then RWD box options that can bolt up (350z stuff)

Yeah I understand that sentiment. However one thing about that, is my car is a budget spec one that was pretty bottom of the barrel in terms of original features. Preserving it as a 3AU 4 speed car might sooth some purists but its not much fun to take on a track, or do the other things I want to with it. The interior in my car was quite shit, and after years of looking I gave up on trying to find nice parts. Until I bought a second car for parts to make this one nice - But then found that the spare parts car was way to nice to part out haha. So now my Dad owns it, and loves it. 3AU that fires up first pop, worlds smoothest T50 gearbox and everything's great. Has been driven in our family all the way from bottom of South Island to Cape Reinga. So this car stays as is. Sometimes I've pined for a factory AA63 model, but then... what would I actually do with it? As completely stock it would be a bit boring. Not keeping it stock, and eventually I'd want to scope creep it away from a 4AGE or whatever anyway. Here's a pic of Dads car at one of the oldschool drag events. Was awesome fun.

6mm stroke difference is putting the pin a lot further down though. Guess i will find out soon enough

My C56 with 95% absent synchros can actually shift amazingly well when I use the ignition cut on gear shift. Because it fully unloads the box in an instant rather than rolling off throttle. J160 has always shifted pretty nice in my experience, guess we will see! Main reason is that I've got a couple of decent gearboxes here already, and the ratios are nice. 99mm stroke on the K24, and a 152mm rod. So a 1.53 rod ratio. Not great. At 4500fps it's not even getting to 7000rpm. Thing is that if people rev a standard K24 to 8500rpm even like that, imagine what you could safely do when the stroke is nearly 30% shorter and pistons are lighter! And yes, a Busa motor or an S1000RR motor in a starlet would be absolutely friggen excellent. Would handle way better with about 1/3rd the weight in the front too. haha

That's an absolutely excellent option, however a 4GR was $650, what's a 20B these days?

Hmmmm maybe, that would be good/bad news. Bad news because it would mean a heavier piston, but good news that if I do make some pistons and rods, could use an even longer rod. I cant use dual E-throttle unless I use some sort of canbus arrangement, but two of something like this would be sweet. This bike makes 150hp with 3cyl, so its at least capable of 300 with a 6.

Yeah, but it looks like since they have a top mounted injector they have more of a bend in the port. So I'll mount injectors high up anyway, as need to remake intake either way. The main problem with DI only is going to be finding non sludgey intakes, will be interesting to see what this motor is like. Has 110,000km.

Long time no post. Two years doing sweet fuck all on the Carina haha. I've spent at least the last year mulling over new motor options. Probably should have just finished getting beams motor going, but oh well. However I've got some renewed enthusiasm at the moment. New motor Criteria: -Capable of big rpm -less weight than beams motor -newer motor / alloy block -Be nice if it bolts to a J160 without adapter These are some of the engine options I've been going back and forth between: 1NZFXE NA Probably a bit too slow for a ~950kg rwd car... But maybe alright with a diff ratio change. Would definitely be the lightest option. Lots of room for activities with intake etc! 1NZFE+turbo This would be great because it would achieve nearly everything I want (lots of rpm, a power increase, less weight) However I do prefer NA motors for ease of working on but also tuning is more fun I think. This wont bolt up to a J160 directly, so that's a headache not present with some other options. Also the exhaust runs down the drivers side which is a bit annoying. Bike motor I am keen to do a bike motor project, but, I think this isnt the right car for it. Too big/heavy. But how cool are bike motors? Built with amazing ports, mega rpm, and sequential box that can shift near instantly. Bloody good. It just really excites me to buy a 10 second bike and turn it into a 14 second car haha. Have you considered a 2ZZ Yes, yes I have. Pluses to this are that it's lighter than a beams motor, VTEC! and built from the ground up for lots of rpm. Good power potential. Downsides - motors are hard to find, that arent either clapped out from high km, or needing to buy a whole car to get an engine. Needs a bellhousing adapter, exhaust runs down the drivers side (steering column/brake master cyl annoyances) Niteparts is currently working on fitting a 2ZZ to AE86, really excited to see how it turns out. 2ARFXE or 2ARFE This is a big late model 2.5 litre 4cyl motor that's gaining popularity for modding. The FXE version uses the same tricks as the Echo motor, however, the factory cams have some pretty decent lift and duration unlike the 1NZ. So it looks like the popular cheapish option is to use a second intake cam in the exhaust side, then you've got 270deg cams with 11mm lift. Pretty sweet. Downsides? It's a tall bugger. I'm definitely not wanting to do anything that requires cutting the bonnet. Might not fit. Also, it would be weight neutral rather than losing any weight from front of the car which was one of the goals. Since it has quite a long stroke, it probably cant rev as high as I'd like. I'm more concerned about engine sound/feel/revvyness rather than outright power. It's a good option, especially if it can bolt to a 3S bellhousing - but being rpm limited to 7500 or something. Blargh! So, yeah. Those were the options I've been considering and trying to decide between. However while browsing through Dodson's trademe site for cheap big block 4 cyl FXE engines I spotted something interesting that I'd not considered... A new challenger appears! 4GRFSE Now this is a bit of a WTF option but hear me out. The 4GR's big brother, the 2GR. Is a 3.5 litre V6 that is commonly swapped into MR2s etc, because can bolt up to a 3S bellhousing. However most of the 3.5 litre versions suit having the motor tipped over for east/west config. I think you need to buy a lexus motor to get the RWD config motor, and uhhh yeah. Lexus tax. The 4GR is the 2.5 litre direct injection V6 from a Toyota Mark X, which is setup for FR config. It's got a rear mounted sump, which by eyeball should easily fit behind Carina crossmember. Also, they're cheap and readily available as Mark X are a fairly common car. Why not 2GR for an extra litre of displacement? Well, the 2GR makes good power but it's got a big bore, big stroke, and will be rpm limited on factory pistons to less RPM than I'm willing to settle for. The short stroke and smaller bore of the 4GR motor means pistons/rods are lighter and the mean piston speed is considerably lower at a given rpm. To be honest I've never really consided a V6 because I think a 4 cyl motor is more in keeping with the spirit of the car. But when you look at the numbers, there's no way to get an off the shelf 4cyl motor that has a big enough bore and short enough stroke for mega rpm. Even the tiny 1NZ has rpm disadvanges compared to it. Another interesting aspect, is that since this motor is DI only from factory. It doesnt have any injectors in the ports, which usually seem to result in more angle on the port. In this case the DI injectors are mounted below the intake ports, so it's got STEEP intake ports. Another good sign for high rpm. The downside is that as per every DI only engine, the intake ports clog up with shit. Solved by converting back to regular injection. Still thinking "why a V6?" (boooo) I think it's going to be possible to get a semi reliable 10k rpm from this motor. Honestly how many engines are capable of running to 10k? How good is that. If these numbers stacked up the same way with a 4cyl motor, I'd use that. But they dont. Also to remove any doubt of this motors absolute peak performance potential this son of a bitch has a modern day TVIS equivalent. shit a brick. I've come to realize from the echo that revving the absolute bejesus out of something puts a smile on your face for longer than outright power does. This motor, the bottom end at least, should be 10k rpm capable with considerably less stress on the motor than any other option from the Toyota stable that I can see. Here's some graphs, because, well, it's my thread and thats how it goes. Bore size 4GR is about middle of the range for bore size, which is a good indicator of piston weight. Keeping in mind that piston area goes up non linear to diameter, so only a few mm more can mean a considerably heavier piston. pistons will definitely be a a fair chunk lighter than 2AR or 2GR options. Stroke length 4GR has got by FAR the shortest stroke out of options. Nearly 8mm shorter stroke than a 1NZ. Considerably shorter stroke than a 2ZZ, which is a pretty good benchmark for a high rpm capable engine. God damn delicious! Compression ratio Lower than some of the options, nothing beats the 1NZ! However 12:1 is still awesome, the fact it's a non hybrid factory engine with CR that high is great. Rod length (Thats what she said) 2AR has the longest rod, but it's also got the longest stroke. Apparently the 2GR and 4GR have the same rod length, which would mean the 4GR block must be more compact. Good news for keeping the engine height down a little. Nearly 10mm longer rod than a 2ZZ. Rod/stroke ratio The highest the rod/stroke ratio number is, the straighter the rod stays when travelling up and down the bore. So less side loading on the bore. This is generally considered a good thing for high rpm, and it also changes how long the piston dwells at TDC and BDC. (higher number favorable for more rpm) An S2000 has a rod ratio of 1.82:1 Having a 1.92 rod ratio is god damn glorious for high rpm from a factory engine. Mean piston speed Rather than picking an RPM and listing the mean piston speeds, I've chosen a mean piston speed (4500 feet per second) then shown how high each motor can rev when reaching this number. The 4GR does wees over everything else. Keep in mind that I'm revving 1NZ to 9k currently, which would be same piston speed as nearly 10k with the 4GR. (4GR will have a heavier piston though to be fair) Sooooo yeah. I think a 9500-10,000rpm motor should be doable, as there are big cams available. If so, it will be friggen wild. Well, there are big cam and stiff valve spring options available for the 2GR - but I'm not yet sure if these will fit the 4GR. Looking at pictures of the head gaskets, it looks like the 4GR has the same bore spacing but just bigger gaps between cyls. I've bought a motor to test fit everything initially. It's not much of a gamble as they're reasonably cheap. I'm hoping things will all work out, but there could be some issues yet. Good thing I got some practice using a hand drill to modify engine blocks with the 1NZ. Might need these skills. Here's a few pics of the next modern Toyota FE motor I'm planning to turd polish into oblivion. I'm super excited about this! There's still a zillion reasons why it might not work out, or something doesnt fit, or blah blah blah. But if it all works how I'm hoping, it's going to be cool as hell.

Its probably so that if the car takes a big shunt, which I'm guessing is likely. The it will deform but not explode into a million splinters like it would if 100% carbon. Or maybe in the past they had a big shard of carbon pierce the radiator. haha

I think its easier for those cars as the engines are solid mounted. It's having to account for engine moving, and the limited front space that makes life tricky.