Rb25/26 Hybrid Issues

[MookRG]

Hey guys we have recently built a new engine for my drifter and we are having issues with the engine being very lazy, i'll list the details of the engine then I'll go into more detail about it's performance.

RB25 Block with 26 crank, rods and 0.5 mm oversized pistons, all factory nissan parts

Rb 25 Tomei poncams inlet and exhaust

Greddy plenum

750cc injectors

splitfire coils

6boost manifold with 3540 and 44mm tial gate

Power FC

With the new engine it makes 340Kw at the wheels on 20psi, though it doesnt feel like it, the old completely stock internaled had only 300kw at the wheels on the same boost but it felt crazy compared to the new one. The stock motor made 300kw by 4000 rpm and held it all the way to 8300, where as the new engine acts really strangely, it is making 15psi by 4000rpm but doesnt actually make any power till 5000 at the earliest.

We are thinking it might be a mismatch in the 25 cams to the extra capacity of the 26, we are going to try putting adjustable cams in it over the next few weeks, but other than that i have no idea how to fix the laziness of the engine.

The other issue we are having is after the car has been driven and is up to track temperature the lifters start to play up, they rattle really loudly and the engine starts to miss badly, we've put a 1.2mm restrictors into the oil feeds, could this be too much, the lifters never made any noise in the old engine.

Any help will be greatly appreciated cause it is well and truely doing my head in.

[R31Nismoid]

cam timing will be out.

It's not a cams issue at all. You should be able to make 350rwkw on stock cams with absolute ease, let alone bigger ones so its not that.

[joeyjoejoejuniorshabadoo]

The stock motor made 300kw by 4000 rpm and held it all the way to 8300

did you mean to say 300kw with full boost from 4000rpm?

cos there is no way it's making 300rwkw by 4k

[wolverine]

^^ 300rwkw @ 4000rpm?? hmmm.

[KiwiRS4T]

What size is the exhaust side of the GT3540?

[JKR-32]

What size is the exhaust side of the GT3540?

Would have to be a .63 wouldn't it?

[MookRG]

3540 has a .82 housing,

original engine made an almost flat power curve from around 4500 to the rev limit, so it probly made around the 280kw mark at 4000rpm, i dont have a copy of the dyno sheet, i might ring Rob at Creatd and get a copy for you. It was very savage power. But very fun.

[Nee-san]

3540 has a .82 housing,

original engine made an almost flat power curve from around 4500 to the rev limit, so it probly made around the 280kw mark at 4000rpm, i dont have a copy of the dyno sheet, i might ring Rob at Creatd and get a copy for you. It was very savage power. But very fun.

364hp at 4000RPM ?

is this wheel horsepower ?