Sideways7

iTrader: (7)

I picked up a '91 RX7 recently, and it has the FD HKS Cast manifold with a GT3582r with an undivided 1.06 a/r housing. I have seen that this manifold is divided, but when I had the turbo off to look at moving to a divided housing I noticed a notch in the dividing wall. Is this manifold actually considered divided, or does that notch make a difference?

Here's the manifold I'm speaking about: HKS Cast Log Turbo Exhaust Manifold FD Mazda RX7 DISCONTINUED [G17141-Z60020] - $551.00 : Himni Racing, Turbocharger, Turbo, Garrett, Turbo Kit, GReddy, Mazda RX-7, HKS, Apexi, TiAL, TurboXS, TurboSmart, Flange, Turbonetics, Exhaust, Intercooler, ACT

Sideways7

iTrader: (7)

Revisiting this almost 2 years later. Any input on this?

cr-rex

iTrader: (114)

The notch could just be for equalization between the 2 runners.... it's all I can think of

billyboy

I'd expect it's just to allow expansion.

Typically the continuous bridges crack/erode with use in that area. It's probably made in some form of Ni-resist, and better than "normal", but very common on fabbed manifolds to fail there - and on the HKS stainless ones too.

Turblown

iTrader: (12)

As mentioned its just so help with cracking, as its not an investment piece, and this is one of the weakest areas on every manifold.

Sideways7

iTrader: (7)

OK, that makes sense. Going for maximum spool on my GT35, so divided housing definitely on my short-term list. I would LOVE to get an EFR (or even a TDX), but its just not in the cards right now.