M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Swaps, Turbos, Buildups => Topic started by: SkidMark on September 05, 2014, 10:35:55 PM
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Hi guyz,
Thinking about boosting my e36 m42 powered 320i. Nothing fancy or extreme, 5 to 6 pounds of boost, diy manifold etc. Not planning on standalone management, plan on using stock ecu, mustang injectors and a rising rate fuel press regulator. Anybody have any good recomendations on what size turbo? Was thinking about trying a t3/t4 .63ar . Also should I mount the afm upstream of the turbo or down? Will the boost pressure make the barndoor in the afm slam shut or freak out if downstream? If the afm is mounted upstream will it properly meter the airflow thru the turbo? I have seen both setups and hope someone knows what works best. Will the disa on my m42 work while boosted or should it be removed? Also looking for a begi rrfpr and wondering how it connects to the m42 fuel rail? Sorry for all the questions I am a newbie to the boost scene. That explains why I sound like an idiot!!! Thanks for any and all help, Skid.
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I'm no expert, but I can tell you a few things I've learned from my 745i.
Most choose to mount the turbo sucking through the AFM. Modding an M50 manifold seems very popular for our M42s. The AFM only measures air volume, so it's a pretty good solution to a turbo. Porsche didn't have any troubles with it - study the 930 diagrams to get an idea of how they did it.
You'll need bigger injectors than those 19# Mustang units.
To minimize boost problems with the stock AFM, make sure you don't dump excess pressure to atmo from your wastegate. Any air that the AFM has measured needs to stay in the intake. Recirculate pressure from the WG back to the intake between the AFM and TB. Use a BOV to manage pressure spikes instead. If you figure out a good way to keep the AFM from abruptly slamming shut, LMK. I've never had the guts to play with it much.
Be sure you have some one-way valves properly installed on your car. You don't want the intake pressurizing your brake booster!
You'll need a WBO2. Even at 6psi, you can easily punch a hole in a piston. The Innovate unit was only $200 last time I checked, and it'll feed a stock narrowband signal back to the DME. I prefer an analog dial, but it looks cool in digital too. Once it's dialed in, go back to the narrowband.
Start with a low-pressure WG spring, and use a manual "dial-a-boost" bleed valve for your tweaking. Consider a magnetic boost control valve too - they can work really well. Feed it pressure from the intake just before the TB, and use signal from that on the WG upper chamber.
The RRFPR doesn't mount on the rail at all. Just splice it into the return line after the stock FPR. I clipped my Begi to the intake manifold.
Best to ask first...an idiot would do it wrong, then ask questions.
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Thanks Dave you da man!!
Definitely planned on the wideband, and was going to step up to 25# injectors, but not sure about the wastegate? I was thinking about using a turbo exhaust housing with a built in wastegate and a 6# actuaitor, but now that I read what you said about not dumping the waste into the atmosphere after the afm has metered the airflow makes total sense. I assume if you dump the metered air before the throttle body the enging will go very rich? Not sure where the bov would live in a draw thru afm, built in wastegate arrangement???? Wit a built in wastegate doesnt the wast dump right back into the exhaust?? Im lost.. I kinda thought I knew what was up??? Guess not!!! Ha ha!! Skid
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Im not even really sure why I want to turbo the car anyway?? I thought it would be a fun project for the fall and winter months, and it will give my wife something to yell at me about.. Also, I will be helping the economy with a major parts purchase list!!! Shit, maybe I will blow up my m42 and get to swap an m50 into the old girl??? :) Skid
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I think there are 2 types of valves on a turbo setup, a wastegate, which controls the pressure built by the turbo, and generally were mounted on the turbo exhaust housing, and a BOV valve, which release the excess of pressure in the area before the throttle when is closed suddenly, avoiding the turbo to lower its turbine speed and then reducing the turbo response or LAG.
Desktopdave i think is referring at BOV valves, isnīt it?
Thanks!
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Yea I had been drinkin and not thinkin on that last post :o... Dave was deffinately talking about bov.. Or for that matter, more like a bypass valve. A bov makes that stupid rice burner pshhuussshhh sound because they are venting to atmosphere. A bypass valve returnes the excess pressure back into the intake, so you dont go lean.
I have abandoned the turbo for now, because I scored an eaton m62 supercharger from a mercedes. It was free and I think with a little fab should work great! Still will be using pretty much all the components from the turbo setup, intercooler, injectors, wideband, bypass valve, rrfpr, etc, but I get to keep my nice exhaust intact!! I will keep you guyz posted!! The g62 eaton is cheap and readily available all over the place so if I can get it to work well it might be cheap hp.. .... Skid