How hard is the RB20 swap?
07-12-2005, 08:44 AM
#16
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Join Date: Jun 2003
Location: Albany, NY
Posts: 609
Originally posted by Cloud7659
hmm....now Im really confused. The RB20 drops right in, no mounts and no xmember necessary, also its compatible with the driveshaft of the 240. Basically, its a drop in and go engine (except for the basic water pump, timing belt, hoses, etc.) But, ofcourse, its weaker than the 25. I knew this but 60rwhp difference? Thats alot!
Now, the RB25 starts out costing more + the $ for the kit from mckinney. It comes out to about 1700 more than the RB20. Not to mention that most engines don't come with intercoolers so theres another pretty penny right there.
Its a really tough decision. Could I increase the rb20's performance to 240rwhp with less than 1700. Probably yes, but Im guessing it would be less reliable.
Confusion.
hmm....now Im really confused. The RB20 drops right in, no mounts and no xmember necessary, also its compatible with the driveshaft of the 240. Basically, its a drop in and go engine (except for the basic water pump, timing belt, hoses, etc.) But, ofcourse, its weaker than the 25. I knew this but 60rwhp difference? Thats alot!
Now, the RB25 starts out costing more + the $ for the kit from mckinney. It comes out to about 1700 more than the RB20. Not to mention that most engines don't come with intercoolers so theres another pretty penny right there.
Its a really tough decision. Could I increase the rb20's performance to 240rwhp with less than 1700. Probably yes, but Im guessing it would be less reliable.
Confusion.
The RB20 and RB25 BOTH have the same crappy side mount intercooler. So either way you will need a FMIC.
The choice is ultimately yours....
07-12-2005, 04:36 PM
#17
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Join Date: Mar 2004
Location: Washington State
Posts: 573
I like the RB20 for reasons stated a few post's ago, more power less $$$. The turbo sucks that comes on the RB20, replace it with a RB25 turbo or Turbo from a single turbo 300ZX, (86-89 I think) and you will be much happier. 89 240SX RB20DET, front mount, exhaust, and RB25 turbo laid to waste a brand new STI! Btw Jon one of our customers has a RB25DET(posted it awhile ago-green silvia) with a HOLSET on it at 10PSI, rode in it yesterday it's absolutely nuts. He's maxing out his injectors, so more fuel is coming soon.
07-12-2005, 06:02 PM
#18
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Join Date: Jul 2005
Posts: 41
The turbo from the oldschool Z's is better than the one the RB20 brings? 
I had no idea. Would the mods be the same for a newer model 240sx as they are for the 1990 one?
Im really leaning towards the rb25, how much more powerful will the z's turbo make it? With a fmic, a bov, a z turbo, and an rb20 would I be as powerful as the rb25? Theres a pretty huge difference in the engine prices. Oh well, Im already in contact with Jb from japanmotor and he may be able to help out. How easy is it to bolt on the z's turbo?
I had no idea. Would the mods be the same for a newer model 240sx as they are for the 1990 one? Im really leaning towards the rb25, how much more powerful will the z's turbo make it? With a fmic, a bov, a z turbo, and an rb20 would I be as powerful as the rb25? Theres a pretty huge difference in the engine prices. Oh well, Im already in contact with Jb from japanmotor and he may be able to help out. How easy is it to bolt on the z's turbo?
07-12-2005, 06:16 PM
#19
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Join Date: Mar 2004
Location: Washington State
Posts: 573
The Z's turbo is a bolt on. You will need to rotate the housings and change the coolant lines around a bit. The RB25 turbo is a bolt on and go. The stock Rb20 turbo is too small, reminds me of the way a honda feels when the VTEC doesn't work. 5500rpm and it falls on it's face. It's all how much money you want to spend. You can have a RB20 all done with better turbo, FMIC, and exhaust for what a stock RB25 swap will run. Btw I have a couple of RB20DET 5sp clips in stock 
07-12-2005, 10:27 PM
#21
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Join Date: Mar 2004
Location: Washington State
Posts: 573
I have one on ebay right now(rkcarguy) for $2295, and another one for $2195. Full clip with everything needed for swap, run tested and guaranteed. Turbo depends on application. The RB25 Turbo is ball bearing and a faster spooler, but hard boost over 14 PSI can blow it up. The 300Z Turbo is bushing and won't spool as fast, but can handle more boost and is slightly larger. Check out my post it's kinda old but still in here"RB20 is going in"
07-13-2005, 12:19 AM
#22
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Join Date: Jul 2005
Posts: 41
Check this out, what do you guys think?
http://cgi.ebay.com/ebaymotors/ws/eB...category=33615
It is literally 5 minutes from my house so shipping is no problem, and it looks like its in decent shape. Give me some feedback
http://cgi.ebay.com/ebaymotors/ws/eB...category=33615
It is literally 5 minutes from my house so shipping is no problem, and it looks like its in decent shape. Give me some feedback
09-11-2005, 01:07 PM
#26
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Join Date: Jun 2003
Location: Albany, NY
Posts: 609
The RB25 spline is 30 spline on 30 spline setup, the 300ZX is 28 spline on 30. It has 2 splines removed 180º off from each other.
That means the 300ZX driveshaft will fit the RB25 trans, but not the other way around.
Length is another issue all together...The lengths are way off.
That means the 300ZX driveshaft will fit the RB25 trans, but not the other way around.
Length is another issue all together...The lengths are way off.
09-13-2005, 04:21 PM
#27
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Join Date: Mar 2004
Location: Washington State
Posts: 573
Everybody dumps on the RB20DET for lack of stock power output, and although I like the engine I don't blame them. Remove the stock turbo and see the tiny hole all your ponies have to squeeze thru, the stock turbo falls off about 2000RPM before redline! Bolt on a Super 60 T3 and have EOPerformance retune your ECU, and you can have around 300HP for about $800 in bolt ons(new turbo is about $500+). Mark from EOPerformance is really cool he does the chipping of the ECU's and a ridealong tuning session for local cutomers(WA state), all for only $250. Then take your stock RB20 turbo and sell it to some single cam honda civic owner so it goes where it belongs!
09-14-2005, 08:17 AM
#28
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Join Date: Aug 2004
Location: Orlando FL.
Posts: 267
This is what I have in mind:
I'm buying a front clip. Then I'll use the stock engine cross member. I have a home made fiberglass hood that fits perfectly, so no problems with clearance. I'm also leaning towards the driveshaft from Mckineys, but I'm wondering how much will it cost me to do it over here in a machine shop. theirs is 549$ shipped to me. The clip comes with everything as far as engine. I'm buying two universal electric fans. I'm buying a hydraulic jack and car tower (the things that hold the car high when working) and a under car dolly for me. I have a 150 piece tool set, along with other miscellaneous tools. I have electrical tools such as tester, soldering iron and heat shrink heater. I have lots of electrical knowledge, and I've changed engine head and oil gaskets, timing belts, replaced all the valves, starters, shocks, and other car repairs. My plan is to take the clip and remove the wiring harness, engine, and intercooler pipes and other salvageable parts and stock them. Then when I'm ready I'll take my motor from my car and take it out from the bottom. Then slide the RB25 in place and lower the car/ raise the engine to place and bolt on, installing the driveshaft and such. I know I'll need some special modifications such as extending the flow meter cables and others, as well as coolant hoses. What other modifications, problems Do u guys think I'll have problems with? I'm also changing the oil and I'm planning on taking the whole pan out to look t the engine, but the gasket may (most probably) break and then were am I going to get one? I'll have to make another one out of gasket material. The oil filter is the one form a 300zx right? the fuel filter I'm changing, getting one for a 300z. I believe that one has the same connector type, so it plugs into the hose, no special screw type stuff. I was thinking about the fuel pump. Should I get a generic one for v6 or v8 engines? Do I have to take out my gas tank and change it or can I install one of those "in line" pumps? I've heard of the walboro, 300z and others but how to install them and were do they go, like I said, so I have to take out the tank? Thank you for all your help. I've been researching this whole swap thing for about a month now, so these are the only questions I found were important
I'm buying a front clip. Then I'll use the stock engine cross member. I have a home made fiberglass hood that fits perfectly, so no problems with clearance. I'm also leaning towards the driveshaft from Mckineys, but I'm wondering how much will it cost me to do it over here in a machine shop. theirs is 549$ shipped to me. The clip comes with everything as far as engine. I'm buying two universal electric fans. I'm buying a hydraulic jack and car tower (the things that hold the car high when working) and a under car dolly for me. I have a 150 piece tool set, along with other miscellaneous tools. I have electrical tools such as tester, soldering iron and heat shrink heater. I have lots of electrical knowledge, and I've changed engine head and oil gaskets, timing belts, replaced all the valves, starters, shocks, and other car repairs. My plan is to take the clip and remove the wiring harness, engine, and intercooler pipes and other salvageable parts and stock them. Then when I'm ready I'll take my motor from my car and take it out from the bottom. Then slide the RB25 in place and lower the car/ raise the engine to place and bolt on, installing the driveshaft and such. I know I'll need some special modifications such as extending the flow meter cables and others, as well as coolant hoses. What other modifications, problems Do u guys think I'll have problems with? I'm also changing the oil and I'm planning on taking the whole pan out to look t the engine, but the gasket may (most probably) break and then were am I going to get one? I'll have to make another one out of gasket material. The oil filter is the one form a 300zx right? the fuel filter I'm changing, getting one for a 300z. I believe that one has the same connector type, so it plugs into the hose, no special screw type stuff. I was thinking about the fuel pump. Should I get a generic one for v6 or v8 engines? Do I have to take out my gas tank and change it or can I install one of those "in line" pumps? I've heard of the walboro, 300z and others but how to install them and were do they go, like I said, so I have to take out the tank? Thank you for all your help. I've been researching this whole swap thing for about a month now, so these are the only questions I found were important
09-14-2005, 08:24 AM
#29
Contributing Member
Join Date: Jun 2003
Location: Albany, NY
Posts: 609
Alot of typing there man....
Driveshafts similar to McKinney's cost me $450 local, all new parts
Installing from the bottom is ALOT easier
No oil pan gasket, RTV
KA24, VG30, RB25 all same oil filter
Fuel filter you are correct
Walbro 255LPH is most common, but get a nismo regulator also. You can get to it from the top, through an access plate on the trunk floor. 4 10MM bolts on passenger side.
Driveshafts similar to McKinney's cost me $450 local, all new parts
Installing from the bottom is ALOT easier
No oil pan gasket, RTV
KA24, VG30, RB25 all same oil filter
Fuel filter you are correct
Walbro 255LPH is most common, but get a nismo regulator also. You can get to it from the top, through an access plate on the trunk floor. 4 10MM bolts on passenger side.
09-14-2005, 09:39 AM
#30
Registered User
Join Date: Aug 2004
Location: Orlando FL.
Posts: 267
Originally posted by jonpowell
Alot of typing there man....
Driveshafts similar to McKinney's cost me $450 local, all new parts
Installing from the bottom is ALOT easier
No oil pan gasket, RTV
KA24, VG30, RB25 all same oil filter
Fuel filter you are correct
Walbro 255LPH is most common, but get a nismo regulator also. You can get to it from the top, through an access plate on the trunk floor. 4 10MM bolts on passenger side.
Alot of typing there man....
Driveshafts similar to McKinney's cost me $450 local, all new parts
Installing from the bottom is ALOT easier
No oil pan gasket, RTV
KA24, VG30, RB25 all same oil filter
Fuel filter you are correct
Walbro 255LPH is most common, but get a nismo regulator also. You can get to it from the top, through an access plate on the trunk floor. 4 10MM bolts on passenger side.
so the only thing I'm screwed is the driveshaft? I'll se what I can get over hur
About the wiring. Yes I know there's wiring services all over the internet, such as mckineys, but what are the main thing I need to do in wiring. The only thing I want my car to do is to show me the MPH and to run, then I can drive arround for a couple of days while I wire evertyhing else. the main thing I need to re-wire would be the dash dysplay right? because everything else is allready wired with the original wiring harness from the RB, like the power to ECU and the sensors, the relays and such right? the only thing missing would be the key cables ( on, acc start, etc.) that should make it start right? how much would it be for a walbro? thanks again!