how much would it cost to put a N/A 3 rotor with a pretty big port job in my 1988 Vert. If possible i would want it carbed, probly cheaper than fuel injected. just trying to get a rough idea from some one that does swaps or has done something similar, not the usual expesivem or over 10k. i want advice from some one who knows.
thanks

 

https://www.rx7club.com/20b-forum-95/my-rx-7-done-cup-holders-3-rotor-semi-p-port-n-setup-stock-subframe-454580/

its expensive, pretty much no matter what. 20b's simply aren't cheap.

 

Forget the idea.
Carbs are a waste of time.


-Ted

 

+1 thats ancient outdated technology.

 

A custom carb. 20B (no other way, nothing is off the shelf) is actually the same, or more pricey than EFI. The distributer is some $$ from racing beat, then some good carbs, ect. it adds up to alot of money. The 20B comes EFI, so you already have the injectors and rails for free. If you are serious about getting the swap done, send me a PM, I have the ability to do it.

 

very cheapest DIY estimates:

20b longblock- 3200
mounts, basic plumbing- 250
header, custom exhaust - 800
used ltx12 or ellv2, or wolf v4(if you can find one) -1000
wiring, etc- 400
upgraded fuel system-200 (ghetto version)
flywheel/clutch - 200 used if you can find it

total: probably 6500 all told.
if you can weld, and have access to a shop and some fabrication skills, subtract 500 or so dollars. other than that, this is about as cheap as it gets, and that includes doing all the work yourself, like wiring, plumbing, and making brackets for **** like coils and relays, and etc.

i know because I did it all myself, at the very lowest cost that I couls, and thats about what it cost me.

pat

 

I would not recoment doing a 20b swap without rebuilding the engine,
thats at least $2,000 more

 

^ i disagree. most imported 20bs (assuming its a reputable establishment you get them from) are in pretty good shape. If you are not planning on ragging on it too badly, there is no reason why you cant drop it in the way it is, and rebuild later if desired.

I divided my project into stages:
1. motor swap, jut get it running, tune for 450-500 hp. -$7k
2. rebuild, port, race bearings, jhb coatings. -$5k (2k without the coatings)
3. bigger turbo and t6 manifold (gt42r probably). tune for 750hp -$2k

pat

 

only 2k for a t6 mani, gt42r and a tune :o

thats one damn good price.
the turbo is 2100 alone.

 

gt42r is ~1800 from the right places. t6 mani is maybe 150 bucks in plate, tube and wire, and a few hours of welding and autocad. tune is 100 bucks for the dyno time.

yay i was off by what 2%?

someday when you start doing some stuff yourself maybe you will understand

this is the last i will say about it: I have the 20b in my car, and it runs. As soon as i get a couple hours off from this rediculous workload i have right now, it will be tuned and drivable. Granted, it took me longer than I expected, but I did it, and It cost less than 7k. If i did it again I could do it for less than 6. Now when i was researching this project, I was told over and over again that I couldnt do it for less than 10. Who came out on top of that one?

 

patman, can you list all your mods and cost? Im still trying to figure out how you did it for less than 10K.

 

i kind of cheated, because i already had a turbo, 3" exhaust intercooler, clutch, flywheel and radiator from the TII. I paid about 1700 total for all that stuff when i bought it.

My project consisted of:
20B and spare tranny- 3400 including gas to go pick it up.
waterjet cut block off plates, manifold flanges- 50 (i did the cad)
2.25" stainless U mandrel bends-80
2 walbros-160
1600cc injectors x3-160
AN lines, fittings, etc- around 600 total.
mounts- 100 of ebay, then i rewelded them.
urethane for mounts- 50 from mcmaster carr
wastegate-200
fpr-40
silicone crap for IC piping-50 (already had some 3" aluminum kicking around)
various other ****-200
used ltx12s w/ wideband option-1300

that adds up to 6400 if you dont count my previous TII mods. add 100 for welding wire and **** like that and its 6500.

if you want to include the TII stuff, that makes it around 8k, which is still not bad at all.

now dont get me wrong, this was a hell of a lot of work, but it is doable. other than the exhaust stuff, there isnt much welding involved, so if you dont know how to weld add a thousand or so and you could still do it with basic fab skills (drilling, tapping, cutting, etc). most of it is just waiting to find good deals on parts and not being afraid to do stuff by hand. for example i saved a couple hundred bucks by using 6 stock trailing coils (the individual coils themselves) that i took apart and custom mounted. stuff like that helps a lot.

hope that helps
pat

 

glad to hear you got lucky with your engines, what if you put the engine in and damage a center plate? it is going to be a nightmare to find one

 

i definately hear what you are saying, but for someone on a budget, i think it is worth it. I also checked out the engine pretty thoroughly and decarbonized the **** out of it. I assume that I will be rebuilding it before I blow it, so I shouldnt hurt it much in the interim. My 20b actually had the mazda sealing tape on the CAS and everything, so I know it hasnt been meesed with. I guess in some situations you might be risking it, but for me it was this or nothing at all, cause I dont have the money to rebuild it now, and I blew my 13b before I bought the motor.

 

I understand completly, I have a 20b here that im going to drop it in without a rebuilt, I have confidence thet the engine is in good condition.

the really dificult decicion is what car is going to get it? the FD or the RX-8?

 

The original post also mentioned going N/A with a big port job. That alone implies that he would be rebuilding with N/A rotors don't you think? I just bought the rotors and seals for my peripheral port 20b and they weren't cheap. Somewhere in the ballpark of $2500 Canadian for everything. Add to that the $4000 for the engine and I am almost at the $7000 that is being claimed above. There is still a pile of other stuff to be done to get the car running - including installing the Haltech E11 V2 - another $1600 I should add. This is also with me doing all the work. Unless you are getting wicked deals on parts or staying completely stock I don't see it happening for under $10k.

 

I'm well over 10K

 

Carbon infested engines do NOT need rebuilding. Refreshing the engine isn't expensive at all. If you want a fresh engine, dissemble it, use a gasket kit and replace the apex seals. The only reason I say replace the apex seals is because the stock 3 piece are ****. Nothing in a 50-80k rotary is worn enough to be out of spec.

 

unless its blown. I bought mine with 46K kilo's on it, with a blown front rotor.

 

^^ that sucks. didnt it come with a warranty?

 

No sir. When I was in Japan, I purchased an entire cosmo as a blown car on the cheap.

 

I built this engine setup for a freind of mine,we are going to put it on a
73 Mazda rx3.I fabricated the intake manifold and the oilpan and the 3to1 header to mount on the stock front motor mounts.The carb is a 3X51MM weber ,mainly used on the porsche engine,I think we paid about $600 for the carb.We will go injected wonce we get the motor broken in and run the Rx3 for a while.

 

^ that's a very hot setup you've got brewing there. you guys need to make a thread when you start work on that Rx-3.

 

As usual, t-von is right on...

 

yes hes right on, asuming the engine you bought is in good condition, for most people it is hard to put the engine in and then take it back out, most of this engines dont have warranties, so to any one thats going to do a 20b swap I recomend you do an engine refresh firts then install it, I personally have seing or being involve in over 50 20b's swaps so expirience do count for something.

this is only an opinion, and he is going NA.