Where to drill intake for FIDLE PWM

[87TurboRaider]

I have a Magna MPI on my Quest motor which is in a Dodge Raider. I want to drill and tap a hole to install a Bosch 2 wire PWM. http://farm5.static.flickr.com/4075/4761270191_e8c9932fd7_m.jpg

 

My question is does it matter where I place the hole on the MPI? On the MPI there are two tapped holes that don't go all the way through as if they're mounting holes for the original setup.

http://farm4.static.flickr.com/3363/3245681144_99a0b9dc91_m.jpg

 

Should I drill a bigger hole completely through, and retap or should I drill in a flat spot?

 

Thanks.

[Chad]

Placement won't matter, it's only used during idle so there is no need to worry about air flow patterns. Most OEM have this air plumbed back into the throttle body itself, but anywhere in the plenum is fine.

 

It doesnt' need to be a huge hole either, 1/4" NPT hose barb one one of those unused threaded bosses with 3/8 hose should be fine. Anything bigger will require tapping a bigger hole, and that plenum wall is just a tad over 1/8" thick to there isn't much meat for a bigger fitting. those holes I tap in it are only 1/8" NPT and it's just enough meat for relaible sealing.

[87TurboRaider]

Placement won't matter, it's only used during idle so there is no need to worry about air flow patterns. Most OEM have this air plumbed back into the throttle body itself, but anywhere in the plenum is fine.

 

It doesnt' need to be a huge hole either, 1/4" NPT hose barb one one of those unused threaded bosses with 3/8 hose should be fine. Anything bigger will require tapping a bigger hole, and that plenum wall is just a tad over 1/8" thick to there isn't much meat for a bigger fitting. those holes I tap in it are only 1/8" NPT and it's just enough meat for relaible sealing.

 

Hey Chad,

 

I wasn't too concerened where the air would come in but if I should actually reuse one of those threaded holes or start a new one. You recommend useing one of them so that's what I'll do. I'll have to step down from the huge hole on the PWM Valve down to 3/8.

 

Thanks

[jahjah]

for aesthetics sake i was going to put mine on the opposiite end of the plenum from where the throttle body is.

[87TurboRaider]

for aesthetics sake i was going to put mine on the opposiite end of the plenum from where the throttle body is.

 

I would consider that but mine is too close to the firewall. It'll be easier to just drill through one if the existing threaded holes and use that.

[87TurboRaider]

for aesthetics sake i was going to put mine on the opposiite end of the plenum from where the throttle body is.

 

Jah Jah,

 

After looking closer at my MPI, I can put one on the back side. I think that's what I'll do. It'll look cleaner and be out of the way.

 

Thanks.

[psu_Crash]

Take a pic of the setup once you get it in there if you can. I've been thinking of going a similar route.

[87TurboRaider]

Take a pic of the setup once you get it in there if you can. I've been thinking of going a similar route.

 

Sorry I already installed it when I read this. It's not easily accessable to take a pic. I should've taken one or two after I drilled and tapped the hole.

[psu_Crash]

That's ok. I just modified my MS for PWM idle control and ordered a bosch idle valve. Thinking of just T'ing into my PCV line for it since I really don't want to pull the intake to drill.

 

How's it working for you?

Edited August 18, 2010 by psu_Crash

[87TurboRaider]

That's ok. I just modified my MS for PWM idle control and ordered a bosch idle valve. Thinking of just T'ing into my PCV line for it since I really don't want to pull the intake to drill.

 

How's it working for you?

 

Well, I have a Bosch and coudn't get it to work right so now I'm going to get a pre '93 Ford PWM. Those are supposed to be easier to work with. Rigt now I'm having a problem with possibly the ignition. When it warms up after about 20 minutes, it starts to stall and buck. If I turn it off, it won't start until it's completely cold. i'm thinking either the coil or ign module. After I figure this out then I'll work on the idle valve again.

 

Good luck with yours.

[psu_Crash]

I used the 3-wire Bosch 0 280 140 505. I was surprised to see how big it is! Already had been using a 1" throttle body spacer so I figured that was the best way to go. I haven't started up to see how it's going to work, but it is the one the megamanual says has been tested. In the morning RTV will be all set up and I'll find out. I plan to do a short write-up on this.

http://a.imageshack.us/img836/5026/img00274m.jpg

[patra_is_here]

where are you mounting the valve? because you can mount it anywhere and just run a hose for the air yes?

[psu_Crash]

where are you mounting the valve? because you can mount it anywhere and just run a hose for the air yes?

 

Yep. I mounted it near where the stock coil used to be and ran hoses. Although it works great for warmup idle control it is causing an issue on boost. See my thread on it.