92 318 intake manifold - want to get rid of it

[jiggaboo jones]

i have a m42, the whole intake system just looks like it sucks. is there a way to replace it with somthing, maybe a 325/328 intake manifold with 2 runners chopped or ITBs from a m3 or anything like that?

if nothing else id like to get rid of the air flow meter and tune it with somthing else, worse case i blow it up and replace it with a 6cyl

[Mannix]

What's wrong with it?  I've not measured port diameters or runner length on this motor, but IME, the Germans do a pretty good job of making an intake manifold for their motors.

What do you want it to do differently?  Runner length and diameter are the two easy things to change - longer runners typically equal more torque, short runners emphasize top end.  

Tuning an intake manifold is tricky business.  Many of the ITB setups I've seen LOOK neat, but they're too short - if the benefits of the shorter runners happen at an RPM well beyond what the cams can support, well.....


Iain (ITBs are not necessarily better than a plenum with a throttle body, FWIW - look at the Honda S2000 motor, huge specific output - with a plenum and TB)

[ose30]

quick and dirty solution how to get rid of AFM is to get piggy pack like Perfect Powers SMT6. Suitable MAF sensors can be bought very good price. I have tested a VW's Pierburg MAF with SMT6 installed into BMW M40 1,8 (8V) it worked quite good even without proper adjustment.

[jiggaboo jones]

the car has no throttle response and the whole system just looks like its choking the motor.  my air flow meter thing has a 2x2" box in it which my car breathes through

i also thought of using a e36 325/328 intake manifold and cutting a runner off each end and sealing it up and using a larger maf

[christophbmw]

the car has no throttle response and the whole system just looks like its choking the motor.  my air flow meter thing has a 2x2" box in it which my car breathes through

i also thought of using a e36 325/328 intake manifold and cutting a runner off each end and sealing it up and using a larger maf

are you serious!? choking the motor? do you know what you are talking about? the 325i intake manifold is more restrictive for the motor than the M42 intake manifold. the equipment the BMW used on our motors is well suited for the motor. the 325 has 68 hp per litre and the 318 has 74, im pretty sure the M42 (although not as powerful as the M20, 325) would be considered a "high performance" motor considering its weight and all the other variables that went into engineering the M42.

as for the no throttle response:
1st; you have to be in the right gear, the M42 wont produce power at 2 grand, its kinda like a motor cycle.

2nd;what kind of gas are you using? whats the condition of the motor? filters? cheap gas will build carbon on these motors and create poor running issues wich can result in poor throttle response.

heres what i suggest you do: but some fuel injector cleaner (cheverons techron concentrate works well) fill your car up with good quality gas (cheveron, 76, shell......91 octane obviously) run the whole tank down to about 1/4 full, add the fuel system cleaner, drive the car nonstop for about 60 miles (it might run a little rough) and then fill the car back up with quality gas. result:a somewhat freshened up motor that (if there was excessive carbon buildup) you will be happy with, trust me:).

[Mannix]

What Christoph said.  I don't like the flappers, either, but they're not the problem they seem like they should be.

BMW does a pretty good job with their intakes; you could likely improve upon what's there, but you need to have a better reason than "it looks like it sucks."  

If you want better top end, you could probably improve on the stock M42 manifold with individual throttle bodies (while losing low end).  

Shrug, Christoph nailed it.  Want more torque?  Get an E36 M3:).



Iain