Author Topic: Bigger TB for M42 ? (Read 8168 times)

daqqer · « **Reply #15 on:** January 22, 2009, 12:34:52 AM »

kk, mines going to be like this then.

atm it needs a bit sanding and polishing, then its ready.

318/6 · « **Reply #16 on:** February 13, 2009, 08:11:29 PM »

Quote from: tjts1;63680

I'm not sure the throttle body is the biggest restriction in the intake system. I would start with the opening airbox muffler (2" round) then the AFM (2" square).

I don't think a bigger throttle body is going to do you any good until you fix these restrictions.

Yikes; way off. Try running the M42 on CIS or L-Jetronic! : )

nickmpower · « **Reply #17 on:** February 13, 2009, 08:56:35 PM »

well the afm is like a 1 inch by 1 inch restricter

tjts1 · « **Reply #18 on:** February 13, 2009, 09:17:14 PM »

Try 2"x2". It is not a restriction.

daqqer · « **Reply #19 on:** March 14, 2009, 07:15:03 PM »

Already planned to make the opening of the airbox bigger. Whats the solution for the AFM tho ?

Jimmy Lewis · « **Reply #20 on:** March 14, 2009, 08:41:54 PM »

There really isn't a solution for the AFM outside of just running a standalone. There is of course a MAF conversion, but bmwman91 worked on it for quite a long time and could never get it exactly right. And not to put a damper on your pursuit for more power, but Metric Mechanic run stock throttle bodies on their 210bhp rally motors. I can't imagine it being that restrictive, though not indicative of throttle response they do have quite a large surface area at WOT.

Maybe rather than trying to force more air into your motor by cutting your airbox in half, you should install an adjustable fuel reg and dial down the fuel pressure a tad.

daqqer · « **Reply #21 on:** March 15, 2009, 05:52:15 AM »

Oh ok. Well on the other hand, it cant make it worse, only better.

Yes i will assemble it all and probably go for the 22 injectors, and if its still too rich i will dial fuel pressure down a bit, or not, i like it rich.

tjts1 · « **Reply #22 on:** March 15, 2009, 10:38:49 AM »

Mine passed California smog check with 22# injectors so I don't think you have to worry about it running rich.

bmwman91 · « **Reply #23 on:** March 16, 2009, 12:43:15 PM »

Quote from: Jimmy Lewis;68313

There really isn't a solution for the AFM outside of just running a standalone. There is of course a MAF conversion, but bmwman91 worked on it for quite a long time and could never get it exactly right. And not to put a damper on your pursuit for more power, but Metric Mechanic run stock throttle bodies on their 210bhp rally motors. I can't imagine it being that restrictive, though not indicative of throttle response they do have quite a large surface area at WOT.

Maybe rather than trying to force more air into your motor by cutting your airbox in half, you should install an adjustable fuel reg and dial down the fuel pressure a tad.

Yeah, it took a lot of work. Sadly, after I finally got it all mapped properly, no power was gained. The AFM poses no restriction on the M42 (the M20 is a different story). I thought the biggest restriction on the M42 was the cylinder head?