GM MAFt and venting the type-S. Exact setup and install procedure?

[Shpyder]

I found lots of threads on venting, recirulating, the GM MAFt, etc. I understand the whole "metered air loss, and hence running rich / stalling" idea, and how the larger GM MAF with translator, if put after the turbo (right after the TB I think, right?) can compensate for the vented air. I even saw Kevin's setup at his POS.com website, but could not find any detailed instructions on installation here on the forums... though I do have a good idea of what to do, I'm confident enough for a DIY install only once I have detailed instructions in a step-by-step form. Yes, I am slow. But my car aint. muahahah.

I actually disconnected my recirculating tube from my type-S and vented today, and O M G. So THATS what it sounds like venting!! I want to vent always just for the sound. Objective clear.

The car DID stall between shifts, if I did not shift fast enough. It died every single time at idle. RPMs went stright to zero the minute the clutch was depressed.

Can anyone help me with the install procedure? What goes where, what kind of stuff I need (aside from the GM MAFt ofcourse), etc...? Can't wait to vent... I was scaring the crap out of people every day with it RECIRCULATED...venting it would be just *orgasmik*.

[Shpyder]

Originally Posted by joemathews

You also may want to investigate other bovs.. but my TurboXS Type H34 stays closed at idle, and runs fine vented even without a MAF-T setup.

Really? So that means that the type-S isn't really 'meant' to be vented on our cars because of its design, but others such as the H34 work fine and the car doesnt stall becase that the way theyr'e designed to stay closed at idle? So that would include other BOVs like Blitz and HKS that are vented, right?

[gsxeclipse97]

Well thats odd, My car doesn't run rich. Also my car doesn't stall when i shift gears. Maybe you don't have the spring tight enough.

[Shpyder]

Originally Posted by gsxeclipse97

Well thats odd, My car doesn't run rich. Also my car doesn't stall when i shift gears. Maybe you don't have the spring tight enough.

Really? Are you running vented on the Type-S?

But that's true, I don't have the spring tight...it's actually at the softest setting. But if its a design issue, the BOV would still stay open at idle... no?

[joemathews]

Originally Posted by Shpyder

But that's true, I don't have the spring tight...it's actually at the softest setting. But if its a design issue, the BOV would still stay open at idle... no?

Strengthen the spring setting. The spring needs to be stiff enough to hold the bov closed at idle and during most driving--it should only release air during shifts. It's important to remember that this is still not doing it "right". But the car will run, with very little apparent difference.

My advice to anyone who wants to run a bov vented without a MAF-T setup is to run one that can also be recirculated (HKS SSQV with recirc kit, TurboXS Type H34, Greddy Type S, etc.)

[JoeWagon]

My car doesn't stall vented either, but it doesn't mean your BOV/car is special and immune. You are still running rich and having all of the effects of losing air.

There is no room after the TB. Technically, the GM MAF needs to go anywhere after the BOV, so between BOV and TB elbow is where everyone puts it. All you need to do is cut a section out of your UICP large enough for the MAF and couplers on each side of it. Then, you wire the MAFt and call it a day. Make sure to plug the intake.

There's no difference in which BOV is better to vent or run recirculated. Each BOV will run perfectly in recirculated/MAFt form, and run shitty vented with no compensation.

[joemathews]

Originally Posted by JoeWagon

There's no difference in which BOV is better to vent or run recirculated. Each BOV will run perfectly in recirculated/MAFt form, and run shitty vented with no compensation.

Except for BOVs that do not stay closed at idle, when venting without MAF-T. The car will not remain running with these bovs installed (i.e. 1g bov, Greddy Type S without strenghtening the spring setting, etc.). I don't think people running vented bovs without MAF-T setups results in a significant performance loss, btw. I agree that it is not the proper way to do things, but people run this way all the time with no ill effects. You don't get the optimum, lean-as-safely-possible mixture that we try to tune for, but the car hardly runs like shit.

[TreeFrog]

so the best bet is to get a BOV that can vent and can recirculate, then experiement see if you can get it running right when vented by tightening it. if not just slap the hose back on, and no big deal...

[Shpyder]

Hmmm. I think joe nailed it: I have the spring set too soft for the BOV to stay shut at idle. I talked to Vince last night, and said the same thing. All I need to do is just stiffen the spring about 2 turns from all the way, and cap the intake.

Running rich gives poor gas mileage, and takes its toll on spark plugs, right? But other than that, nothing worse than that, am I correct?

[joemathews]

Originally Posted by Shpyder

Running rich gives poor gas mileage, and takes its toll on spark plugs, right? But other than that, nothing worse than that, am I correct?

Running rich can give you rich knock. But, because the only times you're running rich are when your bov is venting (after a shift), there is no load on the engine, and I don't think the knock would be serious enough to worry about.

[joemathews]

Originally Posted by TreeFrog

so the best bet is to get a BOV that can vent and can recirculate, then experiement see if you can get it running right when vented by tightening it. if not just slap the hose back on, and no big deal...

I wouldn't call it running "right"...but if your heart is set on venting your bov, and you can't buy a MAF-T setup, this is a way to make it work. I have no long term experience with this, but have never heard of people seeing problems resulting from running their cars like this.

[viet_boiiiii]

God dam u guys make it sound soo believeing haha. I really want to vent too but im afraid of the effects venting without maft. Il wait and see what your guys' car is gonna do after a while til i vent. I dont wanna spend around 400$ just to hear that sound and il prolly just drill 2 holes into my L pipe to fit a greddy type S lol.

[JoeWagon]

I think one thing has been misunderstood:

Adjusting a BOV not to leak at idle is not a correction for the ill effects of venting. I suppose that it doesn't matter too much at idle, but I don't see why a BOV should leak ever.

Shpyder: The stalling happens most when coming down from high RPM. If you are, say, at 5k RPM and you put it in neutral, the car would die. Try slowing down the 'falling' by giving it a little gas. Once you reach 1500-2000RPM, blip the gas again. My car wouldn't stall if it fell from that low.

By tightening your BOV you will fix a vacuum leak at idle, but it will not affect anything else to do with venting. The effects aren't THAT bad... hell.. I'm doing it right now since I bought the car with a RFL. Seems like the longer you run vented, the less the car runs poorly. My 95 hasn't stalled from venting except when I pushed in the clutch from 6000+ when I was doing donuts in the snow.

[Shpyder]

Originally Posted by JoeWagon

Shpyder: The stalling happens most when coming down from high RPM.

I noticed that exact same thing.

Originally Posted by JoeWagon

Adjusting a BOV not to leak at idle is not a correction for the ill effects of venting.

Ofcourse, I do understand that I will run rich until I get some AF control going of some sort. The primary purpose right now is just for show purposes (after seeing a bright PINK Mustang on the freeway with ALtezzas as the only other "mod", the word "rice" won't ever bother me again, lol!)

Well, I hardened the spring, and the car didn't stall as expected, but the venting noise SUCKED. I softened it to the maximum point (testing it for every turn on the spring) to where the car wouldnt die, in hopes of getting the loud whistely kinda squeal, but it just fluttered with a ping noise at best..no where near as impressive, or loud for that matter, as when I had it at the softest setting while venting...if I did it right and am still not satisfied with the noise, I guess the MAFt would be the only way to go...? Or can an AF controller such as an Apexi SAFC help out and substitute for the MAFt? (both setups cost about the same).

[joemathews]

A MAF-T is the only way to do it.