Tomei Powered ARMS M8260 - Manual (Page 33)

SETUP GUIDE
The stock pistons limit is up to 500PS. Forged Pistons are required from this power level and higher.
When running either M7655 & M8260 Turbos at 1.6㎏/㎠ (22.8psi) of boost, the combustion pressure
will be significantly higher which can quickly lead to pre-ignition which can quickly melt or burn the
pistons. This is when the stock pistons will soon reach their limit. So high boost applications will
require a metal head gasket and metal manifold gaskets to be used with Forged Pistons.
The stock connecting rods are one of the weak points of the RB26 engine. When aiming for more
than 550PS, then it is highly recommended to upgrade the connecting rods.
At 1.6k of boost, the ARMS M7960 is capable of 580PS and the M8260 is capable of 650PS. The stock
engine first weak point is the head gasket. So at the very least, the upgrade of the head gasket
and manifold gaskets to the metal type is highly recommend. With the Metal head gasket, 500PS
is achievable with the M7655 Turbos with 1.1~1.2㎏/㎠ (15.6~17.1psi) of boost. With the addition of
forged pistons, the engine can then safely handle boost up to 1.5~1.6㎏/㎠ (21.3~22.8psi). Boost
should be set whilst in 4th or 5th gear. As when it is changed whilst in lower gear, the higher load
in lower gear will result in the wrong boost settings. (It’s not abnormal to see on some occasions
when the rpm reaches its peak and the boost drops).
The actuator has been pre-set at our factory, so there is no need for any additional adjustments.
B t it is best to ha e a boost controller installed to make the req ired adj stments on the day
CONRODS RECOMMENDED: TOMEI H-Beam Connecting Rods
ACTUATOR SETTINGS Not Required {The pre-set pressure is 0.9㎏/㎠ (12.8psi)}
BOOST SETTINGS 1.6㎏/㎠(22.8psi) on a Boost Controller
ITEMS Recommended setting
PISTONS RECOMMENDED: Tomei Forged Piston Kit
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But it is best to have a boost controller installed to make the required adjustments on the day
when driving conditions demand certain performance conditions.
M7655 The stock engine can be able to produce 500PS (with 1.1~1.2㎏/㎠ (15.6~17.1psi) of boost).
The head gasket will have to be upgraded to a Metal type to make it possible. If the
Pistons are upgraded to Forged Pistons, then it can handle more boost of up to 1.6㎏/㎠
and more power gains are possible.
M8260 This turbo was mainly designed to for tuned engines which can handle the higher power
potential of these Turbos. The stock engine is not suitable for these Turbos as the internals
are not designed to cope with this amount of power. Also the stock engine will not be
capable to bring out the true efficiency of these Turbos. So please consider these Turbos
only for higher end tuned engines.
The stock camshafts are inadequate to obtain sufficient exhaust pressure when using larger Turbos.
So camshafts become a vital part of the engine tuning process. It helps change the engines
characteristics to help utilize the larger Turbos potential.
M8260 : TOMEI PROCAM 270°-10.25mm or Similar
TARGET POWER
M8260 ： 650ps
M7655 : TOMEI PONCAM type-B or Similar
M7655 ： 580ps
CAMSHAFTS
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