Sydneykid

My 20 cents; The first time we did a RB30 DOHC 4 valve was almost 10 years ago, in a VL. The RB30ET was making a solid 305 rwhp using an old T04, and that was considered to be a lot of power back then. We used to wave the dyno sheet around the V8 boys just to peeee them off. It had some good stuff, a Motec (an old black one), a CDI, 6 Bosch coils, RX7S5T injectors, mandrel bent mild steel exhaust manifold, Wade cam, Cosworth pistons, Carrillo rods etc. We couldn't see a way to get more power out of it. We could have put a larger tubo on it and turned the boost up, but it was already as laggy as hell. Plus it had 2 defects for running Avgas on the steeet and there was no premium unleaded available then. So we spent a lot of time learning what to do to make the DOHC cylinder head bolt up as not many people had done it. Then 5 of us did it in one day with the bottom end still in the car. Without changing anything else, on the same dyno, it picked up 25 rwhp at 2 psi lower boost, running unleaded. It had more power everywhere and it didn't ping when we slipped an extra 2 degrees of timing into it and made another 8 rwhp. A month or so later we did a solid camshaft conversion and picked up another 15 rwhp. To drive it was a revelation, it reved so easiiy, didn't knock it's head off on hot days and you could change gear without dropping off boost, wow. Since that day I have never built another SOHC RB30:cheers:

643 mm versus 631 mm = 2% conservative speedo readings. That would just about offset the factory optimistic (high) readings. I have no problems with fitting 255's, so 265's would be fine. I run 8" with 35 mm offset, so that's 137 mm out and 66 mm in. A 9.5" with 12 mm offset is 133 mm out and 108 mm in. Rolling the guards would not be required, the rims are 4 mm further in than the 8's but the tyres are 10 mm wider. So thats 5mm, further out, making the 265 tyres pretty much in the same spot outwards as the 255's. Inwards clearance is therefore your only issue.

My guess .....it's the standard ECU doing it's rich and retard thing. But check the plugs, particularly gap, as that can make the R&R worse when they start missfiring:cheers:

In an R32 ECU you can easily tune the fuel and ignition maps. It has no effect on the shift logic.

The blind simply "plugs" into those big square holes in the top of the plastic mounts on the wheel arches. If you look inside the holes you can see the steel clips that hold the roller case and stop it from rattling. When the Stagea gets back from its trip to Canbra I will take a photo for you. It's back for 2 days, then I am off to Sandown for next weeks race meeting and to deliver an RB31 and pick up an RB25. Love that cargo space:cheers:

Well I only have one car to go on (the Stagea), but comparing it to heaps of others (Skylines), the IEBC definitely gives more boost lower in the rpm range. Plus the boost climb is much steeper. It can't be the exhaust because it has a standard one, in fact it can't be anything mechanical because it's all standard.

I try and do it everytime I change all of the bodily fluids (engine oil, gearbox oil, diff oil, radiator coolent, brake fluid) and filters. I figure if the other oils need changing, then the intercooler could probably do with it as well. PS; did you take any photos of your Trust side mount intercooler before you put it in?

The standard ECU runs closed loop for cruise and has stoich set as the target in the aim table. I have had no success changing that via SAFC, DFA or equivalent.

If you tune your boost curve you can have both, with the smaller exhaust housing. But with the larger exhaust housing, you don't have this option. I would ALWAYS recommend using the smallest exhaust housing that suites your power target. That way you choose the boost curve, not the turbine.

My vote for your requirements is the Jaycar IEBC:cheers:

Rears wearing too fast usually indicates poor suspension alignment and/or excessive rear spring rates and inappropriate damper rates. If you fix those problems and use better rear tyres, you won't loose as much traction and wear the tyres out so fast. Plus you will go faster of course.

Hi Brett, nope it's fairly normal, good in fact. It only took 3 flushes to get it clean, I have seen over 10 flushes sometimes.

Hi Mick, some more suggestions; I have tested removing the mesh on the flow bench, I have read the flows and the recorded voltages, IT MAKES STUFF ALL DIFFERENCE. Idle problems mostly seem to come from exposed PODs, sucking hot air. I have recorded over 75 degree air going into a POD while idling in traffic. Add that to a little bit of oil off the filter element on the hot wire and its any wonder they idle at all. Rish and retard, I have read the maps on the standard ECU. As the air flow increases and moves further and further outside the factory parameters, the ECU adds more and more fuel and retards the ignition in ever increasing amounts. It's not linear either, 10% too much airflow doesn't mean 10% more fuel and 1 degree ignition retard, it's more like 15% and 3 degrees. Then 20% more airflow doesn't equal 30% more fuel, more like 45% with 10 degrees retard. etc Eventually, when you get too far from the factory airflow, the standard ECU interupts the ignition to save the engine from whatever it is that is wrong. Earlier Skyline ECU's didn't seem to do much comparision between parameters. Later on the ECU's get faster processors and more prgramming, so they start comparing stuff like throttle position, airflow, rpm, road speed and gear. When the parameters don't line up with each other, the ecu starts the usual rich and retard strategy. So they have moved up from "save the engine from whatever it is that is wrong" to "someone is playing with my sensors". You see this in R33's where there is a dip (or flattening) in the power band as the engine gets onto boost and very quickly exceeds the factory levels of airflow. In Stagea S1's (hybrid R33/R34 ECU) it can by quite swoopy, rather than just a dip. R34's and Stagea S2's are even more sophisticated, they have 3 dimensional mapping. Cams and VE, longer duration and higher lift camshafts would hopefully increase the VE. They may move it higher in the rpm range. But the VE itself may still be higher at the same rpm. So you will get more power at the same RPM. You can then lower the boost a little at the higher rpm so as not to exceed the airflow parameters. The higher VE will still give you more power even at the lower boost. Bottom line, it's all in the tuning and taking the time to understand what is going on. Then tuning around it, but until you replace the ECU, it's an ever more complex set of compromises.

Cleaned your intercooler lately? Pictures of the flush might make you do it sooner rather than later. It makes you wonder when you hear "I put a new intercooelr and it it goes so much better", maybe just cleaning the oil film out of the current intercooler might make a difference.

Some interesting stuff in this thread.... Let's start with injectors sizes, how many RPM does the RB30ET make 200 rkw? Bet it is lower than the rpm that the RB25DET makes 200 rwkw. Lower rpm means the injectors can be open longer for each stroke. So you get more power from the same size injector. I have seen over 400 bhp (230 rwkw) out of an RB31DET using 370 cc per minute injectors running at standard fuel pressure. I can get that out of an RB31DET because it does it at 5,000 rpm and the RB25DET needs 6,000 rpm. That's 20% "longer" for the injector to squirt. A RB20/25 AFM is 80mm (that's OD), same as a Z32 AFM, while the Q45 is 90mm. The Z32 has resolution left at higher airflows because the hot wire is calibrated differently to the RB20/25 hot wire. The Q45 also has this higher hot wire calibration, plus the extra diameter slows the airflow. Removing the screens makes stuff all difference. The standard mapping is very rich, as the airflow goes up, it just gets richer. Usually if it goes lean that means the fuel pump or the injectors are out of flow. You could use and SAFC or a DFA. If you want to know more, have a read of the Jaycar DFA and IEBC thread in the Stagea section. It explains most things. That's enough for now, have an intercooler to clean:cheers:

Moves all the fuel load points on the map up or down. It makes changing from say 370 cc injectors to to 750 cc injectors real quick, just subtract 50% on the master fuel correction. Then fine tune the load points that need it. Much quicker than punching in every individual load point.

You can get parts in stock delivered overnight via Australia Post, for $3 to Foster:cheers:

Sorta. The SAFC reduces the AFM voltage according to how much you need to reduce the AFM voltage to achieve your target A/F ratio. If you need 5.1 volts to achieve your target A/F ratio, then the SAFC won't stop the excess airflow cut off.

Basically you just want to whack your head on top of the bottom end you are about to buy. If you simply undo the head bolts and lift the complete cylinder head off the current bottom end, then all you need is a head gasket. Don't unbolt anything else and you won't need anything else.

That's the Apexi Power FC default, so it is for standard RB25DET injectors.

Sorta. On a fuel map, rpm is one axis and load is the other axis. So you can have a lower duration at 3,000 rpm than at 2,000 rpm, if the load is lower. On a Skyline the load sensor is the AFM, manifold pressure is irrelevant. If it has no AFM, it is usually mapped for rpm against throttle position, again manifold pressure is sometimes irrelevant.

We have 3 fast and wide lambda sensors and we plug one into each primary exhaust pipe. Swap them over to the other 3 cylinders and with 2 power runs we have a full engine log. Gives individual cylinder A/F ratios. We also have a laser heat probe that can be pointed at each primary pipe which gives a good comparison of each cylinder's radiated heat. Both together would be cheaper than 6 heat sensors.

RPM is irrelevant, 40% means it is open for 40% of the time, that can be 40% of 1 second, 40% of 1 minute, or 40% of one hour.

Wow, I am not the only one! I thought I must have been some sort of genius at quiet 044 installs. At least I know there is 2 of us.