Mr. Midas

Hi all!

Another Question here.

Is it possible to use S5 computer,intake, and related on an S4 engine?

What would I need to change, and what would be interchangable between the two series?



Thanks,



Newguy707

drftk1d

yeah but you'd only want to do that if you had a s5 anyway. you don't really want another stock computer either.

ColinRX7

I don't think so the S5 has a limp mode if there is a problem with the oil metering pump, and the S4 has a mechanical one, the S5 is electronic





If you invest any time/money into better engine controls, don't waste time with OEM computers, do it right, and do it once, TRUST me.

mazdaspeed7

The S5 ecu isnt better than the s4 by enough to make it worth the effort. Both are still electronics that have been outdated for 10-15 years. Thats an eternity when i tcomes to advances in computers. 40 years ago, a computer that took up an entire room had less processing power than PDA's now.



The S5 ecu has a lot of issues to deal with in a not 100% stock situation. For the time and money you will spend sorting it out, you could buy an aftermarket standalone, and have all the control and scalability you will ever need.



You can use the S5 intake manifold on a S4 car with minimal work, and its been dynoed at 8-10 wheel hp on a stock car.

Mr. Midas

[quote name='mazdaspeed7' date='May 12 2005, 10:27 AM']The S5 ecu has a lot of issues to deal with in a not 100% stock situation. For the time and money you will spend sorting it out, you could buy an aftermarket standalone, and have all the control and scalability you will ever need.



You can use the S5 intake manifold on a S4 car with minimal work, and its been dynoed at 8-10 wheel hp on a stock car.


[/quote]







Right now I have the chance to get pretty much everything to do the conversion for real cheap. Even an S5 front cover to work with the OMP. If I just put the intake on how would the VDI work? I take it you have a complete stand alone ECU.

What kind do you have, did you have to take it somewhere to adjust/tune it, and in the end how much did it cost you? Would you use the same ECU if you could do it all over again. Just curious...maybe I'll skip the conversion and go strait for aftermarket.



Thanks,



Newguy707

mazdaspeed7

[quote name='Newguy707' date='May 13 2005, 01:35 PM']Right now I have the chance to get pretty much everything to do the conversion for real cheap. Even an S5 front cover to work with the OMP. If I just put the intake on how would the VDI work? I take it you have a complete stand alone ECU.

What kind do you have, did you have to take it somewhere to adjust/tune it, and in the end how much did it cost you? Would you use the same ECU if you could do it all over again. Just curious...maybe I'll skip the conversion and go strait for aftermarket.



Thanks,



Newguy707


[/quote]





My point was even if all the parts are free, youre still wasting your time converting from s4 to s5 electronics. Just putting on the intake manifold will accomplish the same gains. Just get a cheap rpm switch to activate the VDI. MSD makes one.



I had a megasquirt on my fc. Probably $300 after everything to get it installed, but thats hot counting the many many hours I put into it. If you have a lot of free time, and like doing things yourself, the megasquirt is a good option. If you have a job, youre probably better off working a little more and buying a microtec. Go visit the ECU discussions forum here.

Mr. Midas

I thought there would be other probs with making it run right without the S5 computer. If It will work with S4 computer well, then I'll have more recources for the computer upgrade. The rpm switch is a good idea. Does the TPS work the same, or would the S4 TPS need to be used/work on the S5 intake? And what about the BACV?

The ACV on my S4 is a little worse for wear. Is the S5 one the same?



I'll get a little more detailed about why I'm thinking of converting most, if not all intake & engine control related components. (1.) I got S5 rotor housings back from JHB Perf & Eng instead of the S4 one's I sent them. JHB offered to replace the housings free of charge, or(2.) For a steel of a deal, they would send me almost everything from a S5 NA-to-Turbo swap they did recently, including the S5's front cover and transmission.

I figuered "why not?" I like a good challenge, and if it goes together well, I'll end up with even better performance with the other upgrades I'm doing.



Would you believe I've never driven this car? Thats right. Not even a mile! Got it after the engine was taken out and stuffed in the back...Not good

It HAD an auto transmission in it.(hehehe...It just disapeared. ) Now I'm waiting on the one from JHB.



I'll have to start a couple other threads for some off topic stuff like,"How to make man trans mounts?" and post some pics of my bearly running 86' NA manual in a post for "7's helping to control the insect populations"





Newguy707

mazdaspeed7

Like I said, the s5 ecu sucks every bit as much as the S4. It will only be a waste and a huge headache. And no, you will not get better peformance with the S5 electronics. You will get a more tempermental engine. The S5 ecu goes apeshit if everything isnt perfect with the electronic OMP. Its a real bitch to mess with.



You have to use the S4 TB because it has the control for the OMP on it. It takes a slight bit of modification to get the tb onto the manifold, I think you need to grind off a a nub on the bottom of the TB, but its been a very long time since Ive done it, so I dont remember for sure. You will need the 3 pieces of the S5 manifold and the upper fuel rail. Use your stock injectors, the S5 ones have a different plug.

Mr. Midas

Mazdaspeed,

Thanks for all the input. I'm glad you've been so helpfull. It will come in handy once I start the work in a few weeks. I've paid for the parts and they are in transit now. I'll either counitue on this post with my progress or just start a new one when I'm finished with it all.

Another question...I remember reading somewhere about a mod involving the TB. Where the secondary throttle plates are removed I think. Does it do any good or is it just not worth the effort?



Thanks again,





Newguy707

drftk1d

https://www.nopistons.com/forums/ind...howtopic=10968



thats the 2nd gen faq link.