Guest z31freak Posted October 26, 2006 Share Posted October 26, 2006 Hey all, i wanted to get some feedback from you guys on an idea a friend and i have. First all the z31 guys know that mounting the rb can be a pain because you basicly have to fabricate mounts, now i know racinjiter did an awsome job on his project wich is what sparked our interest. There are some companys that sell mount kits for z31 but many of you know they are way expensive so what we want to do is make mounts for you guys to just basicly bolt the rb to the NA crossmember. We have 2 thoughts on this, First we can make a modified z31 mount that will use z31 isolators to mount it, or we will make a full billet bount with special isolators made just for the rbz31 and possibly use the factory mount incase you need a replacement and cannot get ahold of us. Give me some feedback on what you guys think, should we go ahead with this and how many of you would be interested in it? and wich one of our ideas would you prefer? basicly it will be a cheap fix in the modified z31 mount for those that are hard on cash and a full performance package with the special build keep in mind the price should be far less than the other companys chargeing more than your car is worth for a simple mount kit. Quote Link to comment Share on other sites More sharing options...
hotimport Posted October 26, 2006 Share Posted October 26, 2006 I like the idea, but the thing with z31 mounts for the 240/260/280z S30 crown wouldnt be ideal. Originally Stony posted that Z31 mounts would work but they would put the motor a bit forward which isnt all that great in S30 since you got all this plumbing, radiator and 2 intakes with MAF sensors that are on it. But any how to fab out these mounts regardless of the quality you looking at 150-200 at minimum. Where most of the places sell them for like $350 and up, but they are proven quality mounts. So i guess its a good try but you have to get enought people to actually do it and then test it on of the cars. I just dont know if there is a sucess in this one. Dont want to be negative about this but just expressing my opinion. Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted October 26, 2006 Share Posted October 26, 2006 as i said we just want some feedback at this point because its still up in the air, i also know that the rb sits to high when you use z31 mounts wich has been taken into consideration. We have actually came up with a rough draft that will use the stock isolators and you wont need to cut the xmember so thats a plus and the motor will still sit lower. One question i have for you all is i have heard people have had to beat there trany wells to fit the 25 tranny so by siting the motor a little forward may solve this problem but i am not sure we realy need feedback from those that have done it or are in the process to make this thing worth it. Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted October 28, 2006 Share Posted October 28, 2006 OK let me get this straight, You are planning to make the the engine brackets that bolt to the engine right? But if you plan on making a drop down bracket to hold the factory z31 mounts onto the crossmember, it just wont work. There wouldnt be enough clearance for the mounts to sit in the "new" places. As of right now I am going to air hammer the original crossmember brackets so that I can get a wrench on the bolt for the engine isolators. On the tranny tunnel issue, if you decided to move the engine forward more it may help, But the only clearance issue is the speedo sensor. The tunnel only needs about 7/16" massaging to clear well. The speedo sensor hits the transmission tunnel support arch. Also if you decided to move the engine forward you would also be moving the tranny forward, so a custom tranny mount would be needed. Tunnel arch support Speedo interference Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted October 29, 2006 Share Posted October 29, 2006 We have not realy made a decision on the placement as of yet due to lack of information. I did notice the sensor issue wich doesnt look to be very big but it looks to me like you had to tap new holes for the tranny mount puting it more backwards am i mistaken or did you unfact have to mount it more twards the rear? Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted October 29, 2006 Share Posted October 29, 2006 Ok after doing some looking i may be wrong on this one so if i am please corect me. I noticed the rb20det and the vg tranny codes are the same they are both fs5w7 sept ours has 1c at the end not sure what that may mean but isnt it possible due to the fact that the rb20 has the weaker trans that eather our trans could be used on the 20 swaps or the rb20s trans will fit in the well beter. I planned on doing the 20 swap later i know im gunna get slammed but my mind is made up basicly im gunna have a vg turbo car aswell but for me the 20 is more practicle its $1000 less than the 25 i dont plan on makeing gobs of power like you guys so the weaker internals do not bother me and finally i am on a tight budget so im trying to conserve cash and see in fact how much it is going to cost me to do it. Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted October 31, 2006 Share Posted October 31, 2006 I acutally used the factory tranny mount in the factory place, I just put that rusted bolt in the wrong hole, so I dont lose it. The engine mounts to the tranny mount distance is exactly the same for the RB and the VG at 39.5". I believe that the only difference between the rb20det tranny and the earlier vg tranny is the bellhousing. hence the 1c. The rb20det trany is much smaller than the rb25det tranny, I dont think there will be any interference with the rb20det tranny. Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted October 31, 2006 Share Posted October 31, 2006 ahh thanks for clarifying the positioning also thanks for not slamming me for wanting to do the rb20 instead of 25 i have done alot of research on the matter and cost wise it simply makes more sence to goto an rb20 than to even do the na2t swap but i wont get into that unless asked. Only thing at the moment i am going over is the legality of the rb i know its illegal period but im trying to work out something to get it legalised well atleast mine by adding the needed smog equip. You can corect me if im wrong but doesnt the 25 use the z32 tranny? Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted October 31, 2006 Share Posted October 31, 2006 As far as I know the RB series engines are not illegal, however they need to be smog compliant depending on your state. The 25 uses the same internals as the Z32 and same sandwich plate so the bellhousings can be interchanged. If the rb bellhousing is used on the z32 internals and tail section the shifter will sit back about 4" further. Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted November 1, 2006 Share Posted November 1, 2006 ahh thanks for the info very helpful anyway after going over info on the rb20 the only thing that it doesnt have that will kill emissions is the egr system wich i am working on adapting the z31 factory egr setup to run on the rb using megasquirt that should knock down the NOx numbers wich is the only reason the jdm motors fail. I have the entire setup for the egr system and pcv system to bolt to the rb after a couple mods now all i need to know is what the ecu monitors that determines how fast to flip the egr solenoid on and off Quote Link to comment Share on other sites More sharing options...
Dramier Posted November 3, 2006 Share Posted November 3, 2006 Some corrections and additions I'd like to add in. I'm using the RB20 tranny on my RB25 Z31, and there aren't any interference issues with the speedo. Unfortunately, the tranny housing area does have to be "massaged" a bit to get to the bolts and get it snugly in place. Also, the RB engines are illegal in most states period and are only supposed to be used "off-road or race" only. I think the truth of the matter is the RB is not specifically covered by many state laws, and as long as you don't go around smog shops acting like an idiot I would imagine nobody is going to question a Nissan motor in a Nissan car. Hell you could probably even pass it off as an older L28 motor or something to that effect and most people wouldn't be any wiser. As far as the mount ideas go, I would stick to making mounts for the 240/260/280Z guys. I mean there are only two guys in the United States with RB Z31's period that I know of, myself and Racin. Most of the questions and emails I get asking about my car and the swap are from folks that have no clue the kind of work and money involved. In other words, people that will probably never actually attempt the swap. Quite frankly I was pleasantly surprised when Racin's project came along as far as it has and I have every confidence he will be the next finished Z31 and almost definitely a much better swap than mine was! I think what the RB community could use much more than mounts is some options in the manifold department. Both intake and exhaust manifolds in particular would be nice. Not all of us have access to a machine shop or the knowledge/experience to make our own turbo exhaust manifolds or intake plenums/manifolds. But that's just my .02. Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted November 4, 2006 Share Posted November 4, 2006 Dramier, Thank you for weighing in on this one. I am suprised that you had to massage the tranny tunnel. As I did not have to. I figured that you may have more insight than me about certain things about this kind of swap. Quote Link to comment Share on other sites More sharing options...
Guest z31freak Posted November 5, 2006 Share Posted November 5, 2006 I have actually decided against the rb swap myself its just to much hassle and a risk i am not willing to take investing that much time and money into something than have it impounded by chance. I have actually went a different route in swapping in the 7m-gte supra motor i know just buy the dumb supra but i dont like it and that motor has some prety good potential and parts are easier to come by, cheaper, it is street legal, etc anyway thanks for the input and thanks for pointing out the lack of interest in the rb z31 swap. Quote Link to comment Share on other sites More sharing options...
triple B Posted November 12, 2006 Share Posted November 12, 2006 thanks for the great info and insite on this thread guys i am starting my Z31 project soon ( motor is on the way and car is part way stripped already) its nice to know the quirks before hand looks like there might be 3 RB25 powered Z31's before to long 2 of which are in michigan ( weird) Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted November 13, 2006 Share Posted November 13, 2006 Ahhh, I was thinking that there was already 2 in MI, but then I seen you are in Midland. If you need any help send me a message, I will help you out with what you need. Take a look at my thread on the swap I am nearing completion on. I just did the final fit and plan on having it done by january. Wiring is a real mess on this swap. Fell free to PM and AIM me. Quote Link to comment Share on other sites More sharing options...
triple B Posted November 14, 2006 Share Posted November 14, 2006 yeah i am in the very early stages but i am hopin to be at least to startup so i can get some shakedown driving by the end of summer Quote Link to comment Share on other sites More sharing options...
hoov100 Posted November 14, 2006 Share Posted November 14, 2006 im gonna be pieceing together an RB swap in my z31 if i can find a damn 200zr intercooler.. Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted November 15, 2006 Share Posted November 15, 2006 im gonna be pieceing together an RB swap in my z31 if i can find a damn 200zr intercooler.. Are you trying to make a factory looking 200zr? the factory tmic is very prone to heatsoak and is not that efficient either. There was a 200zr for sale in NJ a little while back. He is on other Z forums but I dont think he is on here. Quote Link to comment Share on other sites More sharing options...
hoov100 Posted November 15, 2006 Share Posted November 15, 2006 im not trying to replicate it, but justb asicly want an RB25 in a z31, a RHD conversion would be cool, but mostly pointless.. (could you fit a s13 steering rack and dash into a z31?) Quote Link to comment Share on other sites More sharing options...
Racinjitter Posted November 15, 2006 Share Posted November 15, 2006 You could fit the skyline rack(same mounting brackets), I am not too sure if the s13 rack has the same mount brackets. The dash I have no idea on, but with enough money everything is possible. On the IC I ended up going with a front mount spearco, I traded my s13 greddy fmic, and bought a brand new one. Quote Link to comment Share on other sites More sharing options...
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