GTRNUR

Wow its been a while since Ive signed in for sure. Time gets away... Good question. So much was different between the two designs. The RB315 was a test to see if I could do it. Limitations were for the most part due to local machining capability. Tolerances were an issue. The 3.15 used a single OD dry sleeve, and was almost the same as a kakimoto spacer plate engine, except I used a plate design similar to the OS Giken plate. I did not make the top flanges thick enough either. I can't be sure if it was machining tolerances, or thermal distortion of the sleeves, but the engine did produce quite a bit of blow by. The modified 87mm RB30 crank was also an issue, and was no where near as nicely balanced as the forged 90mm crank in the 3.4. The 34 was a next level build. The sleeves were stepped for max thickness, and were a semi-wet design breaking though into coolant completely in the block. Minimum thickness was 3.75mm and max was 5mm with the 90mm bore, and the new spacer plate also fully supported the tops of the sleeves closed deck style. This combined with far superior CNC machining, and a cylinder hone finish that the machinist does on 3000hp pro stock cars resulted in no noticeable blow by at all. In the end the 3.15 was removed to swap in the 3.4. I discovered the modified RB30 crank had partially sheared the woodruff key on the balancer. That was all that was wrong with it, but it did make the engine a paperweight at that stage. $1100 to make another crank for an engine with blow by issues was not worth it, considering I'd started playing with all Nitto forged internals instead. I hope you found this interesting. Cheers, Ian

I wonder what ever happened to this shell?

It has certainly softened the transition onto boost compared to the 6466 which was savage making 18lb at 3200 just rolling into it in 3rd. Now its around 5000 to 22lb. 1st and 2nd get to about 15lb max not reaching minimum boost unless launch control is used, but the car also struggles for traction in the low gears anyway just rolling into it. More boost isnt going to help that. I haven't maxed the turbo and don't really intend to. 28-30lb should see past 800kw, and it doesn't drop off in top end now like it was with the 6466.

Ah... No I changed to a 7275 Gen2 with a 1:0 hot side.

The 1.3 housing is for a 6466.

I've got a 1.3 housing new in box if anyone's interested? I decided against playing with housings and went with an overall larger upgrade.

Sorry I can't remember where I got it from.

Top and bottom like this pic. Also vertically each side of the core so that the rubber compresses when the shroud is bolted on. Finally that section behind the AC fan ALL needs to be sealed off. Don't worry about covering a little bit of the core with rubber. The surface area is still there, and ensuring COOL incoming airflow (and not bypassed or recirculating hot air) is far more important than a few square inches of core.

Absolutely put foam between the core and radiator. I sealed it to the core everywhere that was possible. Look at where the air is drawn out by the fan. There is huge sections where the shroud doesnt make contact with the core. That all needs to be sealed, behind the AC condensor fan especially, but all round the outside. I used a variety of different thickness rubber strips from a rubber shop. Everywhere the fan can draw air from that it a path of less resistance than drawing through the core, it will do just that. Worst, the air that bypasses the core is cooler than air that passes through the core. This cools the air that would be making your clutch fan work properly. I hope that makes sense.

Something is defiantly not right there. Your setup is almost identical to mine, radiator, greddy swirl pot etc. Im using an OEM 82 degree thermostat though, not the low temp one. My car will run between 84-86 on 34 degree (North Queensland) heat with the AC pumping when sitting in traffic. The clutch fan is absolutely roaring when its like this, as the viscous hub has probably locked up 100% at this stage. Have you tried another viscous hub? They don't last for ever. Its possible that the hub either isn't locking up because its leaked, or its not getting hot enough to cause it to lock up and begin that self regulation thing its designed to do. If its sucking cold air around the radiator core, there will not be sufficient heat to make the viscous hub work properly. When I installed my Koyo radiator, i put in a lot of effort to seal the shroud to the radiator, so the fan could ONLY draw air through the radiator core and not bypass it. Then a lot more effort was put into blocking air recirculation back around the radiator to the front of the car. More than anything when stationary, this helps stop temperature runaway. As the fan is only able to draw in COOL air in front of the HOT core. Consider a coolant air flow leak as being as bad as a coolant leak. It effects efficiency overall of the system. Something I learned from back in my air cooled VW days. If its sucking hot air or recirculating it, the engine isnt cooling.

My recommendation would be to check everything else before going that route. Air/steam pockets, shrouding the radiator so it doesn't recirculate hot air. Bleed the air and/or add an air separation tank. Radiator thickness if aftermarket can be an issue. Too thick is not good for airflow. Above 45mm in traffic and expect issues, as you can't move air through it fast enough unless you have 80km/h of air pressure in front of it. Then, try get an old steel VG30 pully first. Ebay or a wrecker from a nissan pathfinder, maxima or 300zx. It will be cheap because they can't give those things away. Keep in mind it will increase your clutch fan speed too. My current setup, I went back to an OEM pump, with the RB26 sized large pully supplied with the ATI balancer. My 3.4lt's maintains 84 degrees even on hot days. In winter, it rides the thermostat at 82, and oil is the same thanks to my 96 row earls oil cooler.

Nope... They look the same from the outside.

Should be fine if its just an RB26. Only taller blocks have issues. I have a greddy ITB intake on my RB34 high deck, and have had to shave the back off the master cylinder to get it to clear. I still use the booster and an OEM clutch master. The OEM plenum fit with plenty of room by comparison for an engine with the same deck height. Your plenum will be 20mm lower than my setup.

I'm just about to get on the EFR train and get a 9280/1.45 for my RB34. Any recommendations as to where the best place is to source one?

My RB34 with the 6466 Gen1 1.0 opens the gates at 18lb (boost controller off) at 3400 rpm. I've still got a 1.3 housing here... One day I'll get around to fitting it, with the hopes of stopping the kw drop off around 7500 rpm.