so i'm putting an s4 engine into my gsl-se and will be using the gsl-se single stage injection. i was told to just plug the secondary injector locations and it will run fine.

now my quetion is, assuming i wire the aux ports open, can i run my single-stage injection system on the S4's secondary fuel rail? it seems like using the secondary location would have a clear access advantage when/if i send the injectors off to be cleaned.

 

i was wondering the same thing. The fuel would also atomis much better in the secondary location it would seem. anyone know?

 

plus it would look cool with the fuel rail all up on top there.

 

ok so i cross-posted this in the 2nd gen section and aaron cake responded with:

so i think i'll put the injectors on the secondary rail. if i don't like it, i can always migrate them to the center iron.

 

What about running 4 smaller injectors and tuning them with an SAFCand wideband? Could get you the best of both worlds.

 

If he's gonna take that route he might as well ditch the AFM and run megasquirt. It'll cost the same and add a significant but of power.
Grant

 

The throttle body is progressive in nature, meaning the secondary runners aren't active until the throttle has been opened part way. For that reason it'd be a very poor choice to place your only two injectors in that location unless you plan to rework the throttle body to suit.

If sticking with the two -se injectors the best choice is to place them in the center iron where they lived in the original application. I experimented with a few different injector locations, and found nothing that comes close to the idle/low-speed performance of the stock center iron-mounted primaries. In low airflow conditions, atomization is worse with injectors far away from the port, as there isn't enough activity to keep the droplets suspended.

The better choice would be to use the stock 4-injector setup from the S4, as the four wet runner arrangement should give a more homogeneous mixture. With the -se arrangement you are squirting double the fuel in the center runners, and waiting until the combustion chamber to mix with the air from the secondary runners. Not the best from a mixture distribution standpoint, but it is a simpler (less expensive) setup to mfg. To go with the S4 setup requires a suitable fuel controller with injector staging capability, of which many options exist.

 

If you are using the stock se ecu, use only the injectors in their stock location.
their is nothing to block off to the secondary rail, you just bypass the fuel system and hookit up as you would on your stock se manifold. I don't know what advantage you are going to get by dropping in a s4 motor. Your still going to have to use the se afm, then adapt the air intake hoses from the s4 to the se. I recommend cai fabrication. The only way you are going to make the potential hp that the s4 was made to obtain is to use the s4 ecu, afm, cas, and appropriate
dis coil system. Then you can use slightly larger injectors in the secondary rail and
send the computer out to be remapped. their is also someone that is offering ported s4 t/bodys on the 2nd gen section. The s4 intake / t/body is much larger in diameter and will offer better cfm but if you cant properly conrtrol the fuel system then it's not being used to it's potential. Remember that they only added 11hp
on the s4 versus the se. The s5 on the other hand added 25hp over the se.And this was with lighter rotors, higher compression and using a different intake system including a mass air flow sensor. rx7doctor

 

i'm putting the s4 engine in because i'm on a budget. i looked for month for a gsl-se replacement engine and then just went with the s4 engine. a few people have the s4-into-se swap on here and are happy with it.

 

Their is a SE streeported engine on ebay for $600.

 

Never mind, The auction ended it seems.

 

so your putting the gsl-se intake manifolds on the s4 engine? If so, there are no secondary injector holes.

 

Nice to see RENNS active on the forum. Knowledgeable guys are few and far between, and he and Longduck save me much typing!

 

that makes sense. you can get rid of the delayed secondary but you will also loose some low end that way. The best bet seems to be to stay with the stock location. Hopfully when i do this i can go megasquirtand and have staged injection along with no afm or anything. Good luck
Dom

 

no this is how i'm doing it -

s4 stuff going in:
- engine
- intake, throttlebody

s3 stuff going in:
- distributor
- injectors
- computer (already there)
- sensors

 

I totally forgot about the throttle body. I remembered last night. The lower (primary) throttle plate opens a hair before the upper plates begin. However, you can "adjust this out" by tweaking the actuators at the back of the throttle body.

I just worry that fueling the engine entirely through the primary ports will have odd effects at high RPM (the secondaries stay open MUCH longer).