rx7 vs 240sx...

Ever since the demise of my beloved 91 rx7 turbo 2 at the hands of my older brother, i've been trying to make due with a '97 honda civic. Don't get me wrong its a great car. But when it come to spirited driving and autocross i really miss my rwd rx7(or maybe its becuase i hate torque steer?) either way i don't want a fwd car anymore. I've been looking around and it seem i may go with a nissan 240sx (91-93) -since the sr20det motor is a fairly inexpensive swap for the car and makes about 205hp. The 240sx also has 155hp stock, i'm not certain of the torque #s. The reason i didn't think of an rx7 before is because i'm only looking to spend $2000-2500. That mean the only rx7 i can afford is the GXL. I know a GXL is about 145hp stock, but is there anyway to get the non-turbo 13b motor to produce 200+hp? And if so, how and at what kind of cost? I looked into buying a turbo 13b motor, but it seems like it would be cheaper to get a complete rx7 turbo 2 than it would be to get the motor from one. And one more question, how much does an rx7 GXL weigh? (and if anyone knows the weight of the 91-93 240sx, i'd appreciate that too). if any one can help, i'd really appreciate it, i'd love to get a rotary but i'm very uncertian about buying a gxl.

actually all 1986 - 1991 non turbos had the same motor the DEI_II which produced 160 hp@ 6500 rpm and 138 lb. ft. of trq@ 3800 rpm as far as gxl and gtu and so forth those had to do with trim levels my 87 se weighs 2712 without me in it it isnt that hard to push 200 hp from a n/a motor mine is pushy about 190 chip racing beat header with high flow cat no pres and an hks intake and catback and upgraded plugs and a jacobs rotary pro pack so its not that hard its all cost me a total of like 1200 most was for the exhaust rest was shit money not sure bout the 240 sx i belive thet weigh around the same + or - a few lbs my cars is not the fastest (was not) i just totalled mine but it was pushing 14.19@100 mph but now resides in a tree if u want buy a 86 with blown motor and get a mild street ported motor with 3 mm apex seals from mazdatrix.com and mod from there it would push like 14.3 with just the motor put dont do any internal work yourself unless u want a new motor its not exactly easy to properly balance and rebuild a rotary without exp hoped i helped a lil

never got the fuel upgrades in though or the radiator and it neede those severely woulda ran like a 13.40 - 13.70 with the fuel upgrades it is extremely easy though to push a lot of power from a rotary as u prolly know the 190 was at the wheels btw again with the chip pushing the stock fp and injectors to the max
also was looking a an programable ecu once the fuel upgrades went in for tuning but all is scrapped now good luck

"mine is pushy about 190 chip racing beat header with high flow cat no pres and an hks intake and catback and upgraded plugs and a jacobs rotary pro pack so its not that hard its all cost me a total of like 1200"

what do you mean by "no pres" tho?

I think he means no pre-cats. The RX-7 actually comes with 3 cats stock... the regular cat and two pre-cats.

The 2nd gen NAs actually did come with some difference in HP numbers. The S4 (86-88) put out 146hp, while the S5 (89-92) put out 160hp. This is mostly due to a change in the intake and oil injection design, along with a slight change to the fuel system.

It is very easy to get more hp out of the NA... to a certain point. Removing restrictions from the exhaust is the big thing. I'm basically running a straight pipe (no cats) from the engine all the way back, and the difference is immense. You can then have the engine ported for even more power, depending on what kind of power curve you want (porting the engine is like changing the cams in a regular four-stroke engine... with different types of ports you get different power curves).

Once you get to around 200hp or so, it gets more difficult to find power in the NA. Also, the NA tranny can really only handle about 250hp at best. The synchros are relatively weak, and will start to wear quickly if you put too much power through them.

i knew there was some reasson i wanted 89 or up rx7, i just didn't know what it was. i remember now that there was a differnce with the engines. and i was told bu the owner of an 86 that it had 145 hp. the only problem is that its really difficult to find a 89+ rx7, but finding a 91+240sx is alot easier (91+ 240sx is 155hp). i still can't make up my mind on which to get. making 200hp in either car will cost about the same. but it seem that if i want closer to 300hp rx7 will be much more expensive.

GAH! Punctuation!!:eek: :eek: :eek: :eek:

I don't know about the RX-7 being more expensive.

If you want to make well over 200hp, you're basically looking at a swap with either car. It'd cost a lot more to get 200hp out of a stock 240sx than a stock NA RX-7.

The SR20DET and 13BT are usually about the same, price-wise. They also have about the same performance stock, and about the same performance potential. You're going to need drivetrain upgrades with either car as you start to go up in power.

Yeah, there are more 240s out there, so they're easier to find. I don't personally view that as a good thing. On any given day, it's unusual for me to see more than one other FC on the road. However, I'll usually see at least a dozen or so 240s of each generation. It's nice having a car that's a little more rare.

i can get an sr20det w/ tranny for about $1800-2000. the only place i saw a 13bt was mazdatrix and they wanted like $3500-4000 and that didn't include a transmission. where can i get a good 13bt for $1800 and how difficult is it to put the turbo motorand tranny into a non-turbo rx7?

actually the 1bt into a n/a is not that easy it would be easier in that case to go with a sr20det swap then but then again theres absolutely nothing like a rotary and give me a break how many times have u had a spelling error? east coasters rule

13bt well its not easy as far as the wiring goes but hey what do i know my buddy offered to swap a s/c 302 into mine for 3 grand that sounded interesting but i declined

mazdatrix 89-92 level e n/a is best to go then add exhaust intake fuel that i estimate will run low to mid 11's in the 1/4 i hear that the level e motor puts out like 290+hp with venom injectors and a haltech ecu

www.nippon-motors.com
www.fc3s.org

Those are a couple sites that carry the 13bt for under $1000. Search a little and you'll easily find the rest of the TII drivetrain for $800 or less.

Mazdatrix isn't in the business of selling engines for swapping. The prices you got are for them to rebuild an engine, which requires you to send in a core. You need to have the turbo engine already in order for them to rebuild it.

The thing about putting the turbo motor and tranny into a non-turbo RX-7 is you basically need to swap most of the rest of the drivetrain (driveshaft, differential, halfshafts). These parts are cheap though, and they make the whole swap easier. You also end up with a much stronger drivetrain.

As far as the difficulty of the swap... it's really no more difficult than any other engine swap. The engine and subframe bolts right up, without any special mounts. Yes, wiring can be tough... but unless you're getting a full front clip from a Silvia, the wiring can be tough on the SR20 as well. It's generally easier than swapping in a V8, considering that you usually have to cut metal away from the center channel to make room for whatever tranny you're swapping in (unless you're keeping the stock tranny... in which case you're still stuck with a weak tranny that can't handle too much hp and even less torque).


The "Level E" from Mazdatrix is just a type of rebuild. Basically the different levels of rebuilds just determine how many parts are replaced with new ones. The new parts don't really add performance per se. Think of it like blueprinting your engine. It helps your car run more efficiently and closer to factory spec... but it's not going to give you big power gains.

Mazdatrix does offer porting services though, which will help you get some good power.

I'm skeptical of the 290hp estimate from the N/A engine. Really the only way to get that much power is with an extensive peripheral port... which would make the engine very unstreetable. Even then, remember that the N/A tranny can not handle that much power. You'd have to upgrade to a TII drivetrain anyway just to put the power to the ground without tearing up your synchros in a month.

If you need any info on RX7's (FB,FC,FD) or any rotaries in general. Don't hesitate the visit

http://www.rx7club.com

I don't feel like posting a huge message (but yes it is possible to get 200+ bhp from an N/A 13B DEI) so just check out the place and do a search or post a question. You'll find out EVERYTHING you want to know.

all that info is great. now i only have one problem left. i can find an rx7. and i want an 89 or newer.

I just started to read some of the other posts in this thread and just thought you might want to know that all '86-91 motors DID NOT come with the same motor and it's called the 13B DEI all the way around. The '89-91 cars DO have more stock horsepower because of the intake setup using another actuator to change the pressure wave timing, BUT they do weigh a considerable amount more (which in turn means they ARE slower, despite what someone might tell you...numbers don't lie). The best bet if you're gonna get an N/A get one '86-88 (GXL being the best because of the fact you get the 4 piston brakes, etc. just get rid of the rear seat if you get the 2+2 like me), and a turbo get '89-91 because of a different turbo (the great twin scroll). If you just want to swap a motor then get the '89-91 (although the power is higher porting IS NOT as effective as on the '86-88 because of the intake manifold differences). If you need to know anything else...fire away.