I think the factory setup for an RB20DET is reasonable, since the car uses a SMIC and the piping going over the engine probably decreases the distance between the cold side of your SMIC resulting in quicker spool for the little fella.

One of the first things to go on many RB turbo upgrades is the SMIC in favor of a FMIC. When retaining the factory intake, you typically end up with a strange "around the world" setup. I also personally think that the extra heat from sitting on top of the engine doesn't help with the air you've just cooled through the FMIC, but I don't know enough about the physics of heat soak in situations like this to confirm that theory.

Now, when going for a forward facing / intake plenum you get better piping logistics for your FMIC, the potential of running a larger TB for higher air-flow scenarios, and if it's built right it should more evenly disperse the larger amounts of air into each cylinder.

I hope that's what you were asking.

I'm not sure about pricing on your last question. Do you mean RB20DET vs. RB20DE?

 

I think the factory setup for an RB20DET is reasonable, since the car uses a SMIC and the piping going over the engine probably decreases the distance between the cold side of your SMIC resulting in quicker spool for the little fella.

One of the first things to go on many RB turbo upgrades is the SMIC in favor of a FMIC. When retaining the factory intake, you typically end up with a strange "around the world" setup. I also personally think that the extra heat from sitting on top of the engine doesn't help with the air you've just cooled through the FMIC, but I don't know enough about the physics of heat soak in situations like this to confirm that theory.

Now, when going for a forward facing / intake plenum you get better piping logistics for your FMIC, the potential of running a larger TB for higher air-flow scenarios, and if it's built right it should more evenly disperse the larger amounts of air into each cylinder.

I hope that's what you were asking.

I'm not sure about pricing on your last question. Do you mean RB20DET vs. RB20DE?

iam sorry iam an idiot. (op post fixed). I meant to say the 25 intakes..

But how about the bov?? the stock setup is really easy to recirc. Now throw in a forward plenium and how would you position the bov(i have a greddy type s) to recirc without some long tube comming from the intake charge pipe..

 

also makes it a poop load easier to work on, wires/hoses/injectors, etc are either or the top or the bottom of the manifold. Unlike the stock one which is top, bottom, and middle lol

 

RB20DET parts are harder to source and not as common as RB25DET parts, which could be reflected in the pricing as well.

I position my BOV close to the throttle body, not by the turbo. This makes recirculating fairly easy if you want to go that route (although I do not so I may not be the best one to answer this question).

 

i was almost postive rb25 intake manifold bolts onto rb20. ^ And i thought putting the BOV closer to the turbo was more effective than closer to the throttle body?

 

Or no they dont fit but there are adaptor plates out there

 

there are NOT adapter plates...

 

You want it after the intercooler and close to the throttle body since that's where pressure backs up first.

 

so why does the stock setup of the 20-25 have the bov close to the turbo??

 

So if you're running MAF and want to recirculate, wouldn't you put your blow off valve on the intercooler piping just before your throttle body, and then run the recirculating hose in front of your radiator (to hide it) and then put it into the turbo intake so it goes back into the air flow?

I don't run a recirculating bov or maf setup, so somebody else might be able to help you better on this. I just know that putting the bov on the other side is not the preferred placement for higher boost setups (beyond factory).