Chi-RX7

Hey whats up everyone i just recently just started my project (85 gslse rx7)and i bought aholley carb and intake manifold and headers and ect.. but i was wondering wich would be faster..so if anyone know just reply .thank you for your time

rotary_sex

umm english?

85rotarypower

In your title your talking about the same engine. The GSL-SE 13B and FB 13B are the same thing considering a GSL-SE is an FB. Also, could you be a little more specific about what you are asking?

Orbital

Chi, 85rotarypower is right. the GSL-SE engine is a 13b.
I might not know much about rotaries yet, but Ive been told that the second gen 13b's are a lot lighter... lighter=faster

steve84GS TII

The FC 13B is basically the same engine as the GSL-SE,just with different intake manifolds and 4 injectors.The 86-88 made about 10HP more than the SE,then the more refined 89-92 engines went another 15HP above that, with a little more compression and another manifold design.
But they are all basically the same 13B. Non turbo,6 port,EFI engines with roughly the same components and the same dimensions and weight.

The FC chassis is quite a bit heavier than the GSL-SE, except for the base model strippers.The no-option, 4 lug 86-88 cars are about 100lbs heavier than the fully loaded,premium edition 84-85 GSL-SE.
The 2nd gen GXL,GTU and Vert were anywhere from 2800 to 3000+lbs, all with the same 140-160 HP N/A 13B.Only the 3000lb TII had more power and torque, thanks to its 185-200HP turbo 13BT engine.

Chi-RX7

Hey imj sorry guys , i did it last night b4 i fell asleep lololol. but yeah i actully have two engines with me right now? and they are a gslse 13b engine and 88fc gxl engine .. so which one would be better

85rotarypower

The 88 GXL engine is the better of the two. Makes more power because of a better intake manifold design and the 4 injectors instead of just 2. IMO, the FC engine has more potential overall. The GSL-SE engine is pretty good, but the lack of a DIS ignition and the other 2 injectors limits its overall performance.

Chi-RX7

Hey thanx alot man..i always like to get everyones opinions b4 i get donw on the cars.. i actullly been working on rx7 ever since i was 8yrs in Puerto rico (21 yrs now) well thak u man

trochoid

iTrader: (6)

The SE engine has better potential when mated with 12A irons and ported.

redbstd

^^^ hey troch could you allaborate

mikewoodkozar

20B ftmfw, but yeah seriously elaborate please

vipernicus42

iTrader: (4)

12a irons are a 4-port design instead of a 6-port design, and they port-out better. So you can get more out of street porting 12a irons and matching them to the rest of the 13b engine because you get the best of both worlds - bigger rotors, larger displacement, but larger ports.

Since they moved the water jacket o-ring location on later engines, you can't mix-and-match that way with the FC 13b. But a GSL-SE can have a lot of interesting stuff done to it. Heck, you can take 12a irons, GSL-SE rotor housings, and an FC rotating assembly and build some kind of killer frankenrotor engine.

But the only thing I'm unsure of is the injector location. I know that in later 13b engines the injectors have spots they plug into the centre iron, which aren't there on the 12a irons for obvious reaons. But if the GSL-SE 13b doesn't have the injectors there, there's no reason you can't build what trochoid is suggesting.

If you're just dropping the engine in though, grab the FC engine, the RacingBeat front brace, the front cover and oil pan from the GSL-SE and run with it.

Jon

mikewoodkozar

^Good to know, question though; is there anything to be gained by using 12A irons, GSLSE 13B rotor housings and a FD 13BREW rotating assembly?

vipernicus42

iTrader: (4)

Definitely.

The FD rotating assembly is going to be lighter and better equipped for boost. If you check mazdatrix, you can see pictures of the e-shaft from different years. With each passing generation they lightened the shaft more and more by drilling the lobes. The 12a shaft (and I believe the GSL-SE 13b one) aren't drilled/lightened at all.

FD would have the best rotating assembly, 12a would have the best housings for porting that would mate to the GSL-SE rotor housings.

Jon

mikewoodkozar

Awesome

TeamSMS

s5 13b FTW!!! Only thing you gotta do is some wiring and other small modifications to make it work.

84stock

iTrader: (5)

Ahhhhh, he saild he bouth the rb carb set up. So in that case, s3 vs s4 no noticeable difference. Take apart the engines you have (if you plan on rebuilding) and see which are in the best condition inside. If the SE engine has perfect or great housings than that is choice #1. Did you buy the 4 port or 6 port intake??

84stock

iTrader: (5)

If you plan on sticking with the carb and bought the six port intake, than use the 6 port endplates (plenty of port there) and get a 4 port centerplate and street port the centerplate. I am assuming you are managing a budget to some degree.

mzrx7man

iTrader: (9)

so will the SE manifolds bolt up to a newer 13b short block (5th & 6th ports align)? trying to find a replacement for a bad SE block.

RXnos1200

iTrader: (24)

GSL-SE and a FC block are similar in design but has many differences. Atleast that's how I read his post title. Better; I guess that depends on availability in your area. There are a few mods you need to make if you were running a SE block and want to run a FC block now. They can both run good when tuned properly.

trochoid

iTrader: (6)

No it won't, but if staying carb, i.e., 2 barrel wrap around style, RB makes a UIM that mounts to the S4 LIM. This allows one to keep working aux ports if they wish. Oddly, the more ported the primary and secondary ports are, the more one should keep working aux ports to maintain lowend torque.

mikewoodkozar

the RB carb setup will outperform a modified stock FI setup, ie bigger injectors reprogrammed ECU or stand alone?

trochoid

iTrader: (6)

Some companies have reprogrammed the 2nd gen ecus, 5-700 a pop. Everytime one made a change or upgrade, the ecu needed to be sent back in. Will a carb set up outperform FI with a standalone, it should, but it's all up to the choice of parts between them and the tuneing.

84stock

iTrader: (5)

A carb "can" outperform a stock efi system, if you know how to tune it. A carb will "never" match a well tuned efi sytem with a good standalone. The efi will consistantly see better fuel economy. I'm an old dog, have no laptop and I'm not an electrician. I have seen back to back tests on a fc a buddy had running stock efi and then the racing beat 6 port system with a edelbrock and a 12a dizzy. The stock efi was more driveable (especially since the 6 ports were functional) and topend power difference was hardly notable. Sooooooo, it's still carb for me until my skills and wallet evolve.