Bottom mount turbo

[1991 E30 M42]

Has anyone thought about making a bottom mount turbo? With the A/C compressor removed there is plenty of room and you can send the down pipe straight back in between the sub frame and engine mount bracket.

[asubimmer]

I can either use my manifold as a top or bottom, I'm thinkin about going bottom mount. I'll decide in the next few days and go from there.

[BrandC]

it's more sleeper bottom mount

[Shocker]

it's more sleeper bottom mount

But you’re limited to a smaller sized turbo bottom mount. If you want high boost levels you want a top mount.

[1991 E30 M42]

But you’re limited to a smaller sized turbo bottom mount. If you want high boost levels you want a top mount.

If you move the turbo further forward and have it sit lower, you can probably fit a bigger turbo with a bottom mount setup because you wont have to deal with the clearance issues that you have up top. Besides, most people that turbo the M42 aren't going to be running high boost levels, so a smaller turbo would be much more efficient at lower boost levels and with the M42 being a 4 cylinder it would spool allot quicker.

[2002maniac]

Front-bottom mount would make much more sense than rear-bottom mount. Turbo access and piping would be much easier.

If my car werent my daily driver I'd do a bottom mount SC right there.

[1991 E30 M42]

I have thought about doing a supercharger there but ended up not doing it. I have a crank pulley on my m42 that is setup for a flat belt for the A/C and figured that it would be perfect and I was going to have a friend weld up a bracket for it.

[asubimmer]

bottom mount, in the rear, is a no go. there just isn't enough room. this manifold deal is a PITA

[vatos_p]

the biggest problem of all , for bottom mount is that if you are not very carefull and cross a water bump , wile your turbo is hot , then the most probable thing is that you will need new turbo , because it will crack... down there , there is no protection from water... and bumps with water is not a rare sight... top mount is safer , and more efficient from alla views..

[kowalski]

you could easily build some sort of shield tho, plus generally water would be spraying in the other direction , and it would be pretty hard to spray there in any large quantities.

[fabe]

I have thot of attempting a bottom mount turbo set up but I have even less space to work with as my car is a RHD. Will think about it once I've run out of things to play with NA...