Spool Imports: RB34DET Monster Engine

With permission from Spool Imports, I present to you, their take on an RB34DET motor.

Block Preparation

Due to the huge stroke, the block needs to be clareanced to allow the conrods to rotate without fouling on the cylinder block. Leaving 50 thou of clearance allows for stretch at high rpm.

The bottom of each bore has to be clearanced to give that little bit extra room for the I beam conrods.

Annular groove is cut into each main bearing seat to allow for better oil distribution using the multi hole GTR ( RB26 ) main bearings

GTR main bearing smeared with assembly lube - notice the 4 extra holes ( with the recessed groove )  in the GTR bearings compared to just the one hole in the RB30 main bearings.

Block threads are cleaned using a tap - this ensures all threads are clean and free from damage and corrosion. 

Restrictors are fitted to the block to prevent over oiling - a common problem with RB engines.

Inside main tunnel is measured with bearings fitted to check bearing to crank main clearance

Crankshaft main journal is measured to ascertain bearing clearance

Fitting ARP main studs

Installing Billet main caps

Fitting the main cap girdle that interlocks the block and main caps

Installing ARP head studs

Cometic headgasket fitted and waiting for head

SPOOL oil drain - this allows rapid oil return to the sump and helps reduce over oiling of the cylinder head

6 Boost manifold and Greddy Plenum fitted

Finally - installed in car

RB34DET Results

RB34DET 'vs' RB30DET

A comparison between the old RB30DET engine and the new RB34DET stroker engine is complete. The two engines are identical in every way except for the new 95mm stroker crank set up. The purpose of building two near identical engines was the only real way to make a true comparison between a RB30/25 and a RB34/25. The identical set ups consisted of the same ( turbo, boost, cams, cam timing, plenum, exhaust, exhaust manifold etc etc ).
We arent trying to make the most power or we wouldnt be using pump fuel and a medium frame old school T04Z, we are making a comparison. 
The results speak for themselves:

• boost is coming on earlier
• power is coming on earlier and much stronger in the low to mid range
• more peak power on the same boost
• huge increase in low to mid range torque

These increases apply to any setup when comparing the 3.4 litre to a 3.0 litre engine, whether its a 400hp or a 1500hp engine.

The RB30DET boost and power curve is in green and the RB34DET is in red

The RB34 is making near on 150 rwhp more at 4000 rpm compared to the RB30 at the same rpm

At 4000 rpm the RB34 is making near on 60% increases in torque.

More peak power would be achievable using this setup if bigger valves and cams were used. We believe that the head is struggling to flow the extra volume from the increased stroke (capacity) at high rpm.


Obviously a bigger turbo, better head set up, and race fuel would achieve some massive increases arcoss the board. This will be the next engine project built.
We are extremely happy with the results from this comparison and it shows beyond doubt that the RB34 will give more low, mid range and peak power in any setup compared to a 3.0 litre.

RB34 SPECS:

• RB30 Block - bored 40thou
• CP Forged custom pistons
• Decked
• SPOOL Billet main caps and girdle
• Cometic headgasket
• ARP Head studs and mains studs
• SPOOL 95mm Stroker crank
• SPOOL I Beam custom conrods - L19 Bolts
• ACL race series bearings
• Nitto oil pump
• R34 NEO head - HKS 272 / 9.35 cams, Performance Valve Springs, ported and polished by JHH performance
• Garrett T04Z turbo 0.96 ex housing
• Sard 850cc injectors
• 6 Boost manifold - HKS 60mm wastegate
• Greddy Plenum - VH45 90mm throttle body
• OS Giken Twin Plate Clutch
• 3 x 044 Bosch Fuel Pumps
  3.5 inch dump, exhaust and catalytic convertor

NOTE: The std OEM crank girdle can be used with the RB34 crank setup.