well hey im planning on doing a first gen, but just wanted to see what u guys think that i will get whp...with the car being well tuned of coarse


going with a s5 motor with a large street port
RB holley carb kit with intake manifold
RB headers
100shot of nos

and of coarse all the lil other things but nothing major....
so let me know what u guys think...

 

https://www.rx7club.com/1st-generation-specific-1979-1985-18/what-can-12a-do-684046/

currently 2 posts below....sigh

 

dude his question is about 12a...so sigh another time

 

260hp.


Now search. That is not RWHP but FWHP estimate.

 

oh ok and thats with the nos?

 

First the basics.......

The S5 engine with large streetport.....4-port or 6-port.......please say 4-port.

N/A 6-port engines are not the greatest at all to port out,plus they have high compression which is not the greatest thing to run with a 100 shot of nitrous.The 4-port TII engine is very conducive to porting,and has a lower compression ratio,which is very conducive to forced induction (which nitrous IS)

With a 4-port,all the mods,and wet nitrous......Id say you could go 250whp and on up.With more nitrous,the sky is the limit.The S5 TII engine can make 300-400 HP on a regular basis with turbocharging.With nitrous,your accomplishing the same thing,just chemically instead of mechanically.There are many advantages to nitrous too,like self-intercooling and simple intake/exhaust plumbing.The downside of course is timing the amount of injection to prevent detonation and having to refill.....plus its illegal on the streets.
The the HP limit is only set by how much fuel and oxygen you can cram into the engine......and then you find the mechanical limit where everything blows up.

 

oh ok thank you...but im going with a 6por(na motor) well maybe i shouldnt go with that high of a shot...but is it possible that i can get 200whp without nos?

 

Yes its very possible. I'd say 75 shot and a nice solid build and you'll hit 200hp+.

 

First lets compare apples to apples.
The stock HP ratings are taken at the flywheel and the S5 N/A engine is rated at 160HP,with the fancy intake system working and a fairly high rpm range.Lose the stock intake,EFI and aux port system and youll probably drop a fair bit of power....most stock carb'd 13B's make about 140-ish crank HP with no porting.
If you want to make 200 WHEEL HP,then your gonna have to make about 230-240 HP at the CRANK.... thats more than a 50% gain in power.

The intake ports of the 6-port engines arent the greatest for modifying, and the loss of the aux port actuators can hurt lowend power.Thankfully,with nitrous,you are forcefully injecting the oxygen into the engine,so intake porting is a little less important than with turbo/super charging.You can use the stock EFI injector ports in the center iron and use those "snozzle" type wet nitrous systems that feed fuel and nitrous into a standard EFI injector.That will shoot the mix directly down into the engine,without the need for worrying about port flow.
Youll definately want to open up the exhaust ports to get things out of the engine.The N/A engines have that crappy exhaust port baffle in the way,which is pretty tough metal.But once you get that clear,youll be ready to port out the exhaust big enough to accommidate the intake mods.

 

oh ok thanks steve!! dayum dude u know your ****!!!

 

For the record, the 6-port irons are just fine for porting. It just takes some work to fill in the 5/6th ports so that airflow doesn't suck... that and grinding away the divider takes some time.

The stock intake manifolds suck though; runner lengths are all wrong for ported high-end usage and the trickery with the dividers in the plenum hurt too. This can be fixed somewhat with cutting and welding; highest HP "streetport" S5 I know of running the stock style IM (likely cut, ported and rewelded, but externally stock) is at 208rwhp NA; Tony Rivera's EProd car that was for sale.

Given an intake manifold that's not stock at all, and enough port, quite a bit more should be possible. Okay yeah, porting the 6-port irons properly for that kind of power is going to lose you some low-end, but geez it's a '7, not a pickup truck.

 

yep thanks kenku

 

so in ur opinion would u say the GSL-se motor would be better to build? than a s5 6port motor

 

Easier, yes for what you want. Use 12a Irons or an old REPU 13b.

 

oh ok kewl, no im getting somewhere

 

The SE engine is still a 6-port,so the only real advantage is going to be that it mounts up easier.But if your not going to run the stock EFI,then you can bolt up the SE front cover and oilpan to the S5 engine and it will drop in easy too.

The S5 engine has lighter,higher compression rotors and 2MM seals which wear less and seal better.
The SE engine has water seals on the rotor housings,so you can turn it into a 4-port pretty easily with 12A irons......but,finding a 4-port TII engine to build is probably easier.

 

well i have two motors, i have a SE motor and s5 motor ready and all im waiting for is for my recing beat holley kit and thats about it, once it gets here then il just have to make a decision

 

For a zingy N/A setup,Id go with the S5.
Even without porting,it will outperform the SE engine.
Its probably in newer shape being younger,its got 4-5 more years of technical advancement then the SE engine,a factory 8000rpm redline due to the lighter rotors and seals and a higher compression ratio which means more power all around.

 

yep, well ive decided to go with the s5 motor and recieved the holley kit today and have my NAWS READY!!!! for a 100 shot and with a large street port on motor....so we will see what i can do with this car...

 

Yes, probably. recently Drag Sport magazine published articles by Jim Mederer documenting a 6-port street port SE 13B engine with various intake configurations. With Holley carb, max power was 224.3 HP (SAE corrected), with muffled exhaust--engine was dyno'ed out of vehicle. With S5 engine lighter rotors, and 4 ports instead of 6, you could expect higher numbers.

 

hmm i wonder if i can use the se housing and use the S5 rotors in it? would it just go in easily??

 

That's why we want new guys to use the search function and do lots of reading.

This information has been covered in many many many many threads.


Since I'm already here.


Yes, you can use the rotating assembly from the S5 in your Se engine.
If you want a 6 port engine with lighter rotors then you use everything from your Se Engine except the rotating assembly.

Thats if you want to retain the SE injection system. Or if your S5 donor has bad internals such as housings and you have a good SE engine.

If you are going carb'd and you have a good donor S5 engine then it would not make sense to put the lighter rotors in the Se engine.
If you are going for a 4 port 13b engine and have good donor parts from the S5 then you could use the lighter rotating assembly from the S5 engine and use the SE rotor housings and use 12a irons.