Upgrade a 3.2 to a 3.4?

[Trakrat]

OK all... I've been researching what's involved with getting a set of 3.4 pistons and cylinders and slapping them on my 3.2.


I came across the following post from Wayne on here:

"...if you upgrade to the 3.4 pistons and cylinders (not necessarily recommended for use with the Motronic system)."

Does anyone know WHY Wayne mentions that this is NOT recommended for the Motronic system?

I plan on keeping my Motronic fuel injection system on my '87.

I believe I would only be increasing my compression from 9.5:1 to 9.8:1... but after more searches on here, I've come across some threads with others saying a twin plug is needed???

[TRE Cup]

We have not had any problems with motronic 3.4 builds. contact Steve Wong at 911chips.com for help in programming a chip that works with this

[Bill Verburg]

Originally Posted by Trakrat

OK all... I've been researching what's involved with getting a set of 3.4 pistons and cylinders and slapping them on my 3.2.


I came across the following post from Wayne on here:

"...if you upgrade to the 3.4 pistons and cylinders (not necessarily recommended for use with the Motronic system)."

Does anyone know WHY Wayne mentions that this is NOT recommended for the Motronic system?

I plan on keeping my Motronic fuel injection system on my '87.

I believe I would only be increasing my compression from 9.5:1 to 9.8:1... but after more searches on here, I've come across some threads with others saying a twin plug is needed???

There are or at last were 2 versions of the 98mm Mahles available
v1 has a wedge dome for use w/ CIS and Motronic, 9.8cr
v2 has pocketed high dome for use w/ carbs/mfi & other ITB type intakes, 9.8cr, These pocketed domes allow for S and racing type cams to be used

[Trakrat]

Originally Posted by Bill Verburg

There are or at last were 2 versions of the 98mm Mahles available
v1 has a wedge dome for use w/ CIS and Motronic, 9.8cr
v2 has pocketed high dome for use w/ carbs/mfi & other ITB type intakes, 9.8cr, These pocketed domes allow for S and racing type cams to be used

Good to know... thanks... I'll verify what kind of piston shapes they are before purchase.

[Trakrat]

Originally Posted by TRE Cup

We have not had any problems with motronic 3.4 builds. contact Steve Wong at 911chips.com for help in programming a chip that works with this

Wonderful.. thank you. I bought a custom chip from Steve last year and he had mentioned that once I have all my mods put in place, to let him know and he'll reprogram the chip.