single port vs. dual port?

[GTDrifter]

alright, so I drive a 2000 RS with a 2.2 single port transplant done by the dealer. I'm wondering what the differences are between single and dual port...meaning power, fuel economy, etc.

I'm tossing around the idea of throwing on some 25d heads (dual port) and welding my headers back to dual port.

I heard that the single port has better low end torque and the dual port has better high end torque but I'd like to know for sure.

[StatGSR]

even though everybody pushes for dual ports, the single ports are the better flowing heads, the downside is that you can't just go out and buy off the shelf UEL headers.

as for putting on 25d heads, that is a horrible idea, it will decrease the compression and make it run like poo, it will also require a different intake manifold. if you wanted dual ports, you should use the old ej22 dual port heads.

Do you know what year and model the single port engine in your car is from? is it a phase 1 or 2?

[GTDrifter]

I think it's a phase 2
and the 25d heads would come from a complete 25d engine so parts wouldn't be an issue

ive been looking for stock single port heads for about 2-3 weeks now with wtb threads on rs25 and searching partouts and all and have turned up nothing.

[Wiscon_Mark]

I thought the PhaseII EJ22 went back to dual port heads?

[GTDrifter]

I'm not positive what year the engine was from because it was swapped long before I bought the car but the engine only had 97k and came from an elderly couples car so it was in tip top shape

[chuckthefuk]

EJ22:
Dual port is Pre-96
Single port is 96+

[Matty2Hotty]

EJ22:
Dual port is Pre-96
Single port is 96+

Efficient wise? Mpg & WHP on the two a huge difference?

[chuckthefuk]

@ 135 BHP were talking single digit changes... its not increasing its intake capacity its just increase its exhaust efficiency ..

If your looking for sound just elongate one of the runners on the manifold... if your looking for power... a EJ22 is not the right path to go down...

basic use is Ej22 dual port heads + ej25* bottom end... You get to keep your EJ22 sensors / manifold making it a plug n play setup essentially.

-Chuck

[Wiscon_Mark]

Phase I EJ22 90-96 = 135Hp 137 TQ
Phase I EJ22 97-98 = 137 HP 137 TQ
Phase II EJ22 99-01 (only on 99 Legacy) = 145 HP, 149TQ

[chuckthefuk]

90-94 EJ22 OBD1 are not the same as 95 OBDII dual ports / 96 OBDII single ports...

That list is miss leading....

[Wiscon_Mark]

I suppose, but I was just listing power figures...

I should mention that 96 is a hybrid year - some had dual ports, some had single ports.

What was different about the OBDI exhaust heads? Were they physically different in design or was it more of just some small emissions differences? I was under the impression that aftermarket dual port headers would still bolt up to them.