Tristan363

is it for the idle air control valve? if so i can grab a pic since mine is off the car currently.

Ya I knew about the vct and the head bolts which are not really an issue my vct barley ever was hooked up before the swap since the plug was damaged and always slid off so I'm not to worried about that. I've located two rb26 heads one for 500 and one for 800 both are in great condition and on top of that i have a complete rb25 s1 head that i can sell. I looks like I'll probably go with the 26 head if i go with a 1mm HG I think that will make it work a bit better. IDK if any of the rb30 guys could way in on this that have used the rb26 head over the 25 that will probably be the closest swap to what I'm doing.

Hello and thanks for reading I've been searching the forums for any info and cant find really anything saying I will have compression issues so here's the question. I have an rb25 block that is already built im talking ACL bearings CP pistons (8.5:1) Manly rods ARP head/crank studs and all. Im looking at powering a 9180 borgwarner efr turbo running E85 should be able to make 600-700 hp with room to grow. Originally was just going to build an rb25 head but I'm toying with the idea of using an rb26 head instead since it already has solid lifters and it has more cam options so i was wondering if I might have low compression because from what i understand the rb26 head has a slightly larger combustion chamber 64.5cc vs 62.5 in the rb25. (https://www.tomeiusa.com/tool/stock_engine_data.html) Does anyone have any experience with a swap like this. And I know i should just buy a rb26 block but im located in the states and rb's are much harder to get a hold of here plus I've already got a built block. Thanks in advance for any help. I've also got a solid rb26 hhead and all the components sourced and ready to purchase this little inquiry is all thats holding me up.

you honestly don't notice the rears not being wide when doing this or at least i don't on my r33 the only people that will notice are the true die hard fans.

Ya I've driven it in 3 different states the current one being Texas with no issue's from law enforcement so far. i doubt its federally legal but at this point I really don't care. I've also had an insurance company pay me out ten thousand for a wreck that wasn't my fault thinking they were going to total the car but ended up not.

would swapping the heads around mess with compression, weather is was rb26 block/r25 head or the other way around because of dome depth on the heads? or are the domes the same depth?

How many pounds of boost was it runnning with the stock green label because those run out pretty quick it sounds like it something to do with the afm. Thats how mine acted when i was fitting a z32 maf to it. also what series ecu are you running?

Nice to join the community I'm located in the states I've had my r33 for about 8 years now currently in the middle of building my motor I'm looking to make about 600-700 hp thanks for reading. If you wanna know more about it feel free to ask.