High Rear Rotor EGT from Turblown (Turbosource) IWG Turbo Manifold?

RW Atelier — Wed, 03 Jun 2026 17:02:31 GMT

Dear forum,

I have been chasing down what's causing the extremely high rear rotor EGT. After one WOT pull, my front EGT max out around 860 C (~1580 F) while the rear can skyrocket to over 970 C (~1780 F). My engine tuner suggested it could be the Turblown IWG Turbo Manifold, where the rear exhaust runner has two 90 degree bends and hence more restriction. So far, I have found another REW-swapped RX-8 having the exact same issue: https://www.facebook.com/groups/3063...4214422719819/ https://www.facebook.com/groups/3063...0461739761752/

I'd like to know if there's others using this IWG turbo manifold and monitoring the EGTs, what numbers do we see, as I don't want to jump to the conclusion here. If anyone has more even EGTs, then I know for sure there's a mechanical or tuning related problem on my car.

My Setup:
- Street Ported 13B-REW by Lucky 7 Racing
- EFR 8474 IWG .92 A/R
- IGN-1A Smart Coils
- Full Function Engineering Hall-Effect Trigger Wheel
- Haltech Nexus R3
- ID1050X primary injectos, 1700X secondary injectors

So far I have tried:
- Replacing the ignition coils and wires.
- Swapping the front and rear EGT probes & Trying a new unit
- Swapping the front and rear injectors on both primary and secondary fuel rails
- Compressions are 101/102/95 psi Front, 97/97/90 psi Rear. Normalized to 250 RPM and standard atomsphere.

I am about to pull the spark plugs and trying new ones, just in case it's the rear leading plug causing it all. I'm open to suggestions. I know that Turblown is making a V2 IWG manifold that has larger rear runner diameter which seems to improve things a bit.

RX7Club.com - Mazda RX7 Forum - Single Turbo RX-7's

High Rear Rotor EGT from Turblown (Turbosource) IWG Turbo Manifold?