5 replies to this topic

[syko_tek1]

Is it possible to use the dx head on an Si? I have a dx head and I just need to have a running spare car.

[badpenny]

Is it possible to use the dx head on an Si? I have a dx head and I just need to have a running spare car.

Yes you can. You will need to use the Si distributor (mainly for the box that is on it.) Your compression numbers are going to be lower due to the domed configuration of the dx head, and the crossflow design. Use RTV sealant and make sure the intake manifold is connected securely. The aux port on the head is the reason I state this.

[zakats]

if it is a usdm you can... well if you have an EW5 intake manifold and electronics
cdm dx heads dont have cvcc so you could use the regular usdm si stuff

[wyatt89]

Yes you can. You will need to use the Si distributor (mainly for the box that is on it.) Your compression numbers are going to be lower due to the domed configuration of the dx head, and the crossflow design. Use RTV sealant and make sure the intake manifold is connected securely. The aux port on the head is the reason I state this

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the si has a bigger chamber, wouldnt that mean more compression

i just converted my dx motor to fual injection w/si head and the chamber is def bigger and has a larger exhaust valve

[zakats]

the si has a bigger chamber, wouldnt that mean more compression

the si head does have a bigger chamber which results in lower compression, the CDM dx head would keep it about the same as stock,

[Gimpalot]

the si head does have a bigger chamber which results in lower compression, the CDM dx head would keep it about the same as stock,

The compression is a factor of the combustion itself.....
When the "explosion" of materials occurs, it fills the volume of the chamber, so having a smaller area to fill would mean the compression would go up, given the same quantities of material are sent into the chamber.

i.e. Zak and bp are correct.....