xsspeed Posted April 14, 2023 Share Posted April 14, 2023 i love how we all now know way too much about 4gr's and 1nz's thanks to romandayf 1 2 Quote Link to comment Share on other sites More sharing options...
kpr Posted April 14, 2023 Share Posted April 14, 2023 1 hour ago, xsspeed said: would be interesting to see if you could, I'm guessing either the cranks are mounted higher in a 4gr or the piston compression height is significantly different between the two (or both) to account for such stroke difference. solution is only a custom set of rods away if need be probably just the usual shorter block height on the 4gr, usually a toyota / most manufacturers move. save some material cost and make engine bit shorter. so yeah longer rods would be needed. probably giving a rod ratio well over 2. bigger bore, bigger valves bit more capacity. probably blow the budget, but would be pretty cool if the crank did swap over 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 14, 2023 Author Share Posted April 14, 2023 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. 1 Quote Link to comment Share on other sites More sharing options...
xsspeed Posted April 14, 2023 Share Posted April 14, 2023 Man I love how I can draw RB comparisons, RB24 is also a unicorn with rb26 bore and rb20 crank, only carb'd and only available in malaysia 1 3 Quote Link to comment Share on other sites More sharing options...
Raizer Posted April 14, 2023 Share Posted April 14, 2023 1 hour ago, Roman said: 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. $5200 inc DHL shipping from AliExpress haha 5 2 1 Quote Link to comment Share on other sites More sharing options...
keltik Posted April 17, 2023 Share Posted April 17, 2023 Full development on the 4GR then build a 5GR to drop in there once we know it all works. /I'm told a 13B would happily do the power and rpm numbers you're looking for 3 Quote Link to comment Share on other sites More sharing options...
Atex Posted April 17, 2023 Share Posted April 17, 2023 Did the Honda J30A4 engine cross your radar when looking for light weight v6 engines? Quote Link to comment Share on other sites More sharing options...
MS51HT Posted April 18, 2023 Share Posted April 18, 2023 No doubt you've already done the comparison somewhere - but thought it was interesting to look at the 2GR, 3GR and 4GR engine specs side by side (or more accurately top on top) 2GR 1 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 18, 2023 Author Share Posted April 18, 2023 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 1 Quote Link to comment Share on other sites More sharing options...
GARDRB Posted April 18, 2023 Share Posted April 18, 2023 14 hours ago, Roman said: 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 Wash your mouth out. VZ motors suck, MZ are at least alloy Quote Link to comment Share on other sites More sharing options...
Roman Posted April 19, 2023 Author Share Posted April 19, 2023 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. Quote Link to comment Share on other sites More sharing options...
shrike Posted April 20, 2023 Share Posted April 20, 2023 How easy/cheap is it to get spare heads for these? Any cheap dead motors around that you can play with first? Quote Link to comment Share on other sites More sharing options...
Roman Posted April 21, 2023 Author Share Posted April 21, 2023 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. 3 Quote Link to comment Share on other sites More sharing options...
Honda Ass Dragger Posted April 21, 2023 Share Posted April 21, 2023 Honda F1 Cylinder Head Sections from both a V10 and V8 3 Quote Link to comment Share on other sites More sharing options...
~Slideways~ Posted April 23, 2023 Share Posted April 23, 2023 On 21/04/2023 at 12:07, Roman said: 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. I wonder if some periodic water injection would help? Quote Link to comment Share on other sites More sharing options...
tortron Posted April 26, 2023 Share Posted April 26, 2023 My research into squishbands is that the sharp edge promotes a turbulent mix when it gets squished My GN head had less detonation when I rounded them. But it had other things going on with the piston shape. Nothing negative happened, there was also less carbon in thrle head compared to stock sharp band 2 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 26, 2023 Author Share Posted April 26, 2023 Interesting. Im guessing a lot of these things are necessary for stratified charge, but less relevant when youve got high up port injectors. Will eventually buy another motor or 2 to try some other stuff too. 2 Quote Link to comment Share on other sites More sharing options...
Roman Posted April 26, 2023 Author Share Posted April 26, 2023 On 23/04/2023 at 13:41, ~Slideways~ said: I wonder if some periodic water injection would help? Not sure. I guess running a catch can would help, its probably a lot to do with oily buildup from that. But the valves were almost road cone shaped with shit piled on top. Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted April 30, 2023 Author Popular Post Share Posted April 30, 2023 Some results from the 3500cc motor running same cams as I'm planning. 405whp on E85 at 7500rpm. So if I could manage that same power/litre would be around 290hp at wheels. Yikes! Hopefully keeps pushing powerband up more with smaller motor. The motors are obviously a bit different so there's no assurance mine would react the same. Also worth noting that these results are great but it sounds pretty yuck. Would probably sound nicer with some longer manifolds rather than short 3-1 setup. I'm still considering how I could fit a 6-1 manifold after @h4nd poisoned my brain with amazing engine noises with that V12 video. 9 1 Quote Link to comment Share on other sites More sharing options...
xsspeed Posted April 30, 2023 Share Posted April 30, 2023 Sounds yuck cos hasn't cracked 9k rpm 2 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.