Jump to content
Ultimate Subaru Message Board

EA82T blow through turbo system with intercooler

Recommended Posts

Posted by this person below. please direct all questions to him.





09-16-2006 12:15 AM


87 RX Blowthru Setup

I just made a blowthru setup on my 87 RX. I've been previously venting to the atmosphere and running pig rich during shifts. Thinking back to my Eclipse I thought about how I miss my GM blow through setup. At this point I had a few mods done. Cone air filter, exhaust, top mount intercooler with custom piping, and an hks ssq bov. I liked the shock that people got when they would hear my car vent, however, I hated the fact that I was passing a couple of cops the other day doing about 25 mph and shifted and my car popped from the richness between shifts. This of course drew their attention to me, and wasted a bunch of fuel. I went home and thought to myself, this is the last time. After kicking the idea around with subarutex I decided after work today to do it. Soooo......This is what I did.


The goal: Move the mas sensor after the intercooler and before the throttle body. Doing this you can vent to the atmosphere without running pig rich, due to the fact that the air is metered after the blow off valve position. (everyone knows that if you vent and the mas stays in the stock position it dumps air into the atmosphere instead of into the engine, thus making your slow compensating ecu use an improper balance of fuel/air. Too much fuel, too little air and the car bogs.) Warning, attempt this at your own risk etc etc. Mine runs perfect but, if you mix up your wires, who knows what'll happen.


1) 1 at a time, I cut my mas sensor wires and extended them 2 ft and taped them up with electrical tape.

2) then I got (2) 2 1/2"- 3" silicon couplers

3) Using a universal Mas - Air filter adapter I connected the mas to the intercooler

4) next I connected the mas to a 90 degree bend using the 2 1/2"- 3" adapter

5) connect the 90 degree bend to the throttle body using the other 2 1/2" - 3" adapter

6) Connect your cone air filter to the stock intake inlet where the stock mas used to fit (this will require a 2 1/2" opening on the Air filter connection end

7) Lastly wrap the mas extention wires in electrical tape and route them in a safe location


**side Note** There are 2 white wires in the factory mas harness, cut them before the shielding (they go into a shielded black wire). Don't be dumb and mix these wires up like I did, this is why I said to extend the wires in step 1, 1 at a time. No mixup all smiles. If you mix the wires up you will get a check engine light. So do it right and don't panic.


So now that the blow through setup is complete, you can vent your heart out and not pop, not bog, and not run pig rich. Also as a cool side effect, if you blow your intercooler piping off, your car will still idle perfectly. Why? Because you moved the mas to before the throttle body and the car is still getting the right a/f ratio. Now you can calmly pull to the side of the road and fix your piping instead of your car dying in the middle of the road. Pictures to Follow.


The only other thing I can think of to make this setup better is, Get the lip on the universal airfilter adapter beaded so you can clamp your piping down and not blow it off. This will be your weak spot in your setup.

Edited by subeman90
clean out dead links

Share this post

Link to post
Share on other sites