redbstd

just what it says. which one gives better power, power band, etc, etc, etc.

steve84GS TII

The S5 is active and more complex,requiring the S5 ECU to operate correctly.Its very similar to the mechanical aux ports,except it acts upon the primary and secondary intake passages and is controlled electrically by the ECU.I dont imagine it would be an upgrade over the S4 if the VDI valve isnt working,which requires a full S5 EFI swap.

The S4 is passive,like the GSL-SE intake.Its pulse tuning is built into the design of the plenum and it likely can be used with any ECU since there is nothing to control except the aux valves,which are strictly mechanical.

redbstd

so for my SE go for the s4? because i was going to go to itb's but they're a little expensive right now.

steve84GS TII

Yea,the S5 is harder to find and will never work 100% right if you dont have the S5 ECU.The S4 intakes are everywhere and seem to be a popular mod on the GSL-SE engine.Not sure if they are THAT much of an upgrade in regards to power or torque band,but it couldnt hurt I guess.

mjm4jc

In my opinion, the swap would not be worth the trouble. Keep in mind that the 2gen 7's have 11 more horses than the SE's and some of those horses are due to the fact that they have lighter rotors. With that said, how much HP do you think you will get by converting to the S4? I suggest working with what you have.

Mike

bugman1973

i have an s3 intake on my s4 engine. low compression rotors and i blew up the tired SE engine not on purpose

walken

iTrader: (6)

i had a stock se with full stock exhaust. it was very slow. so the following upgrades were installed one night. MSD coil, E-fan, and a K&N drop in filter. none of that really made that big of a difference.

removed the intake manifolds and cleaned everything. removed the 6pi sleeves. removed the rods and actuators from the s3 manifold jb welded it all up and reinstalled it. then s4 mid and upper were jb welded, siliconed, and installed. topped off with a s4 modded throttle body and a home depot flex hose to the AFM.

after this upgrade the car was a completely different animal. if you floored it you would over-rev it almost every time. it flew through first that fast. it would keep up with my s4 that had a streetport, intake, and full 3" exhaust.

I would recommend this upgrade to every se owner, but... the engine was old and split apart on the rear iron to housing. maybe they can't be spun that high?

bugman1973

cleaned S4 intake yes with fully functioning 6th port system would be best i don't know why people take out the ports and jb weld them. don't do it it kills reliability. my function perfectly and actually runs better then a modded one it town.

RacerX7fb

I have an S5 intake on my SE with fully functional 6-ports, VDI and BAC while still using the stock ECU and AFM, no rats nest. Dyno test showed no power drop til about 7500 (stock is 6000 meaning less shifting while on the track), achieving an additional 8 RWHP on my overheated engine full of block sealer and still passing CA smog. Why, because it looks sexier than the S3 or S4 intakes

redbstd

somebody told me the s5's were electronic aux ports is that true?

redbstd

but this one lookes like its mechanical......WTF

http://cgi.ebay.com/ebaymotors/Mazda...spagenameZWD1V

85 FB

Do you have a picture of your engine bay with that setup?

steve84GS TII

The S5 uses the airpump to activate the aux ports instead of the exhaust pressure.Its still mechanical,just actuated from a different source.The airpump is a better choice since its output is strictly rpms dependant,wheras the exhaust pressure is dependant on throttle position,rpms and exhaust system condition.

The VDI valve is actuated by either vacuum or airpump pressure,I dont remember which.But the actual activation of that valve is controlled by the ECU via a solenoid in the rats nest......so techincally its electric-over-pneumatic.

Rx-7Doctor

iTrader: (13)

I believe that those who have used the S5 system and had the VDI work are using a RPM switch to activate and control the correct RPM that they were intended to function at.

RacerX7fb

Yes doctor you are correct in my case. I have the RPM switch in the glove box and can play VTEC controller excuse me, VDI.
If my engine bay looks cluttered to you guys then good! Smog technicains don't question the factory look, especially since it says MAZDA right on top of the manifold.

The S5 2nd gen utilizes positive air pressure from the air pump to do its functions.
Everything works on my car the way its intended to from stock airbox to the split air control solenoid to the anti-afterburn valve to the thermo-wax cold start, even without the rats nest. The 6-port still opens via back pressure.

I port matched all the runners and mildly knife edged the throttle body. The center intake ports on the LIM do not match the S3 block though and that's where filling and grinding took place. The secondary injector holes were welded shut as well.

If you were to add a turbo to your car or for simplicity then the S4 manifold would be good to go. For N/A, if you are up to the task, the S5 all the way.

bugman1973

so you welded the secondary injector holes. why didn't you use temporary block offs so that you could add the secondaries later. just wondering its not a big deal. i just had plans to do something similar with mine but use more advanced 6th port actuators. i do need to find out what the normal durations of the six ports through all the 6 port engines are and base the actuation off of. I'm doing so research now but when I'm done all let all the plans be know.(to a point I'm going to keep some secrets to my self) I'm defiantly going to be doing some things to better the 6port engines.

redbstd

Thats perty, see thats what i was looking for. If you dont mind, how long did it take you to get it running. What im planning on doing is using my megasquirt to run fuel.

bugman1973

if you are planning to use your megasquirt you can run all for injectors just like the second gens id go ahead and bump up the secondaries to match with how high the SE primaries are. they are rated at 680cc just get ones that are a little higher than that say 850cc and you'd be good and have more horse power then most of us

redbstd

Thats the plan im going to get my SE bridgeported but im a little woried the irons wont hold. Are the se irons weaker? Because everybody who modded there SE seems to always break the back iron. If it is wich rears are stronger?

bugman1973

if it were me i wouldn't use the SE irons id go find me an S4 or S5 short block. just rebuild one of those you'll get a stronger engine and reliability. and you can bridge port that and not have to worry about messing up the SE irons. just keep it stock and put it back in if you decide to sell the car later down the road. i know the car wouldn't be an SE for say anymore but it would be nice to be able to save the engine from being ruined by accident. just think about that stuff. i was out testing the power band and adjusting my ports and i ruined on of the SE engines. blew an apex seal right out and ruined the housings i have good irons but the rotor housing from the rear was done. thats why i went with the S4 plus it has lower compression rotors. I'm trying to build an N/A 250+hp street car. I'm shooting to do this with just a street port but a bridge might be in my future.

RacerX7fb

I didn't use plugs or block offs because I wanted the inside of the secondary runners as smooth as the primaries. Also I have 3 or 4 more S5 manifolds laying around.

trochoid

iTrader: (6)

If you aren't boosting, the SE irons will hold fine. You also shouldn't need huge injectors. The 2nd gen NAs have 4-460 cc injectors, the TIIs have 4-550 cc ones. You would need to be over 225-250 hp to even push the 550's.

bugman1973

that is good to know ill just pick up two 850cc for my secondaries when i do my S4 or S5 intake i plan on doing a 250-300hp N/A street/road racing car. might run a 50 shot of nitrous, that wouldn't be too bad would it? it doesn't need to get great gas mileage. I'm going to try to pick up a newer Cosmo when i go to Japan and use that as my DD. if i can find one

redbstd

so i should run the 550s fo primary and my 680 for secondary? or do i have it backwards?

Latin270

Thats about right.