Mating Rb26dett Throttle Plenum On Rb25det (neo) Head

[GTS4WD]

Im not expacting a MASSIVE increase in power, as a final figue. As Michael said, the differences should be huge.

As there is 1.5m less of intercooler pipeing and individual throttle bodies the turbo will spool quicker, reach peak boost at a lower RPM and be alot more responsive.

More responce means I have a widerpower band, more usable torque and power at lower RPM.

Please bear in mind this is going in a fairly light R32 too, not a bulky R34.

[jeffboyracer]

looks like a f**kload of effort so far, congrats dude! make sure to keep us all posted on your progress!!!

[TriniGT]

Any updates? I am getting back my head hopefully this weekend. My setup looks like it came so, hope everything goes according to plan.

[PM-R33]

Yeah, how did this all go? I remember reading this thread ages ago and forgot about it.

[GTS4WD]

The wait is finally over guys! This is it - the one of a kind RB25DET NEO with GTR plenum, NO adaptor plates!

Engine fired-up no probs, now taking it easy for a while to run-in the head and make sure there's no leaks etc. The engine asks for a tune-up.

Latest details of the mod are as follows:

- Used the standard GTR air box, AAC valve and air regulator under the plenum (for last two, harness modded with connectors to suit).

- Used the standard GTR water tube under the air box and water hoses to suit. One outlet from the water tube was plugged.

- Used the standard GTR blow-off valve setup.

- Ditched the Neo oil cooler/filter holder as it interfered with the air box and used instead a standard oil filter holder from any RB20/RB25.

- Used for now the NEO fuel rail and injectors. Will upgrade later to GTR rail and higher flow injectors.

- Used the NEO TPS (throttle position sensor) with adaptor piece as seen in the photo.

- Used the NEO boost sensor (connected to the plenum).

- Ditched the throttle motor and sensor (NEO traction control system).

- Ditched the carbon canister purge solenoid and connected the canister through one way valve to the GTR factory port.

- On the turbo side, used a Turbosmart elbow reducer 3in to 2.5in to connect the turbo outlet with the GTR air tube

More pics to come!

Edited May 20, 2009 by GTS4WD

[GTS4WD]

[GTS4WD]

[GTS4WD]

Edited May 20, 2009 by GTS4WD

[TriniGT]

Sweet, getting back my head this weekend so I will throw up some pics to compare and then I will be PMing for the much needed advice. Still need to replace the guides and get them reemed though . Sweet job nonetheless, how is the response and PM me details as I am going with an RB26DETT bottom end with the Neo head and keeping the VCT and using the RB26 covers and whatnot, may just keep it single turbo as I already got my HKS cast iron setup with external gate.

[PM-R33]

Wow looks really good man. Never realised how different the neo cam covers, coilpack cover and timing belt cover looked compared to the RB25.

[robots]

So how does it feel ? Did reuse your old head bolts? Change head gasket ?

[GTS4WD]

Same dead studs and a Cometic Head gasket

[strelok]

Good day.

Please explain how solved the problem with welding metal to head unit? What measures should be taken not to led the geometry?

[TriniGT]

Do you think there would be any problem with leaving out this bolt as my machinist forgot this and widened the water outlet for the GTR setup. Thinking about leaving it this way, your thoughts?

[strelok]

Do you think there would be any problem with leaving out this bolt as my machinist forgot this and widened the water outlet for the GTR setup. Thinking about leaving it this way, your thoughts?

I think this is a bolt guide, nothing more.

Has done similar work, perhaps someone would be helpful:

http://picasaweb.google.ru/strelok.vc/2009...feat=directlink

[TriniGT]

Thanks for clearing that up. Is yours up and running as well?

[strelok]

No. It is still at the stage of assembly. Plan before the end of the month run.

At the moment, is a problem - how to control valve VCT because ECU will stand by RB20DET. I do so out of ECU, the external electronics.

There are thoughts about this?

[robots]

No. It is still at the stage of assembly. Plan before the end of the month run.

At the moment, is a problem - how to control valve VCT because ECU will stand by RB20DET. I do so out of ECU, the external electronics.

There are thoughts about this?

Strelok, ya tebe otvetil na nisme.

[Adriano]

I would certainly try to get a bolt back in there. Its not a ocating bolt, it clamps the head down to stop a coolant oil leak from those 2 passages.

[TriniGT]

I would certainly try to get a bolt back in there. Its not a ocating bolt, it clamps the head down to stop a coolant oil leak from those 2 passages.

Hmmmm this would require me to get the area filled and tapped for the bolt as the inside of the head in that area was ground to mate proper with the RB26 ITB water ports. Gonna ponder on this for a bit, I am think the headstuds should have more than sufficed for this but I will rethink it.