I have a 90 civic with Dpfi. I'm doing a couple of mods on it, but I've found that the o'ring between the T/B and the mounting plate has been discontinued... Any suggestions? I've come here cuz u guys always seem to have the answers.

 

Really people??? Nothing???

 

Are you referring to the black plate? The STD plate has a smaller hole making less air come in and also the butterfly in the TB does not open all the way. What kind of mods are you doing? For more power? If for more power, don't waste your time on the DPFI manifold. I and other tried. Like getting blood from a stone. My STD has a MPFI swap. Big difference between the two. Power wise, throttle response and for future power additions. Even ready for a motor swap since the wiring is all set up.

It's your car. If you do get nice power from your mods please let us know. I am curious to see if it can be done. Good luck buddy and keep us posted.

 

I'm taking that restrctor plate out so it can breathe better. I have a sohc zc engine and I put the pm5 ecu in it already. Taking the plate out will help it breathe. But I can't find the o'ring for it.

 

You can dremel the plate bigger for more air. But if your using the STD TB the lower butterfly only opens 75%. So, it's still restrictive. The DX tb opens 100%. Some people remove the first butterfly in the tb. Gives more intake roar but idle suffers.

 

Dude just go multi point.

 

I think the plate he is trying to take out just lifts out - no dremel required.
Grabbed this pic from a different thread -




Removing the first butterfly (tandem valve plate) doesn't do much of anything for power.
The airflow on the D15 is terrible - there is no consideration to runner length, there is a 90* turn from the throttle body into the intake manifold, etc
The tandem valve plate helps direct air over the primary injector. This is a good thing.
You might get a negligible gain in response time, if anything at all, by removing the first plate.



As far as your o-ring, did yours completely disintegrate?
If not, then just reuse it.
It isn't exposed to any pressure so it just needs to be a good fit.
A thin layer of a silicone sealant can be used to fill any voids.

 

Thanks guys I ended up using the old o'ring and I took the base plate from a DX rather than using a dremmel on the on I had. Taking out the butterfly plate I lost a bit of low end but gain in the top end. Thanks guys.

 

Did you also use the DX throttle body instead of the STD?

 

No I used the std throttle body.. Why?

 

The DX throttle body butterfly valve opens 100% at WOT. Look down into the STD at WOT and it doesn't open all the way.

 

Ok brother I'll check it out. U think it's still gonna pass smog.. R u talking the top butterfly or the bottom.?

 

Sorry...I second guessed my self and glad that I did. The top STD valve does not open all the way but the bottom does. Had to garage and check in crate at my old DPFI. Pass smog without it? I don't know. It does control a vacuum valve. Should idle a little rough but if your not throwing codes it should be good.

 

So the top butterfly on the DX t/b opens all the way at wot? Yeh I kept the butterfly on mine. Kinda bogged without it. I do know that replacing that base plate with the one from the DX gave me some gain at 4000rpm and up.