Advanced GT-R notes. RB26
Its been a few years since I wrote up some GT-R basics. Since then , a few more cars in the country , a few more races. A few more Ultimate Street Car Challenges. A few more passes down the dragstrip. These items are things we have actually tried unless otherwise noted. Proven combinations , proven things.
Road Racing
There are different requirements for a car that is road raced than drag raced
Drag Racing
Go fast , straight line.
Oiling
This gets its own section. Oil is the blood of the motor . Without oil you have a dead motor. And when it dies , it normally spits parts out the side of the block. Heed this warning.
Oil pump drive
R32 Crank
The drive on a stock early R32 crank is about 1/2 the width of the late R32 /R33/R34 crank. It can be modified with a crank collar to increase the width.
R32 late , R33 , R34
Oil pumps .
Stock
Stock is Ok up to 8,000 rpm as long as you have an wide drive crank
N1
It’s a stock pump with an upgraded spring to increase oil pressure
Jun
The mostly highly recommended pump
Nismo
Good up to 8400 rpm and 500 hp
Tomei
New oil pump still not released. Larger drive gears
Reinik
Oil Pans
Stock
Stock the front differential is built into the oilpan. The stock pan is baffled , but the capacity is fairly low. About 4.5 quarts.
Tomei
Sump extension
Trust
Sump extension , hangs lower than the crossmember . It’s a bit low for a street driven vehicle that may encounter a speed bump.
Custom
The point is to add capacity. At high RPMS , lots of oil ends up at the top of the motor . The oil pump sucks air , feeds air to the bearings. The motor spins a bearing , lots of bad things happen very fast.
Oil Baffle plates
Tomei
Baffle plate – replaces stock plate – has rubber trap doors
Nismo
Baffle plate – replaces stock plate – has metal trap doors
Oil Restrictors
Stock
2.0 mm restrictor to the head.
N1
1.2 mm restrictor – in N1 blocks
Tomei
1.5 mm restrictor – installed on top of stock 2.0 mm
Oil Coolers
The more and bigger you can fit , the better. The RB26 has oil cooled pistons. Oil squirters. 7 Main caps . 2 cams. 6 rods. The RB26 puts a lot of heat into the oil at 8,000 rpm. If you road race , it will not take long to get the oil temp up into the 130C range. Nismo recommends keeping oil temp to a max of 110 C during an endurance race. They will replace the bearings every race if they get the oil temp to 110 C
Head Studs
ARP
Main Studs
ARP
One of the main studs needs to be ground to clear the axle tube.
Rod Bolts
ARP
Rods
Stock
N1
HKS
Greddy
Tomei
Carrillo
Crower
Pistons
Stock
N1
JE
Greddy
HKS
Crankshafts
Stock
Full counter
2.7
2.8
2.9
Blocks
Stock
N1
RB30
Headgaskets
Camshafts
Stock
R32
R34
Tomei
HKS
Greddy
JUN
Turbos
Stock
Twins
Single
Plenum
Stock
The problem with the stock plenum is that #6 cylinder gets the most air , and the overall distribution of air is not balanced.
Nismo
Nismo has a new plenum that helps to balance flow in the plenum. #1-#5 are bell mouthed , but #6 is not. It’s a little larger to increase plenum volume.
Greddy
JUN /
Tomei
Throttle bodies
Stock
Upgrade
Single conversion
Head Porting
Quench pad
Crank damper
Stock
HKS/ATI
ATI bolt on
Front differential
If you send 50% of the torque to the front diff – say in the area of 250-300 hp – you will break the front diff. When it breaks – it spits parts out of the front diff case. Which is also the oil pan. So when you break the front diff you break the oil pan. Which means now you must remove the engine to change the oil pan. People have broken front diffs around stock HP with a hard launch off the rev limiter. Use caution , or use a torque split controller to limit torque to the front wheels.
Transmission
Stock R32 /R33
There were several upgrades to the R32/R33 transmission. They all break 3rd gear.
Early R32
Push style clutch
Late R32/R33
Pull style clutch
Stock R34 – Getrag
Clutch
Stock
Single plate
Multi Plate
Carbon
ATS
Tilton
Exedy
Spark Plugs
Stock
NGK
Denso
Apex
HKS
Greddy
