Cubes

I'd say without a doubt you are still up around the 6000-6500rpm peak power mark. haha ROY.. Nice Avtar. lol

Its been a good conversation. I've learnt a little.

hrmm..

It does work out cheaper to buy the rb26 head off the bat. Stuffing around with valve springs, solid lifter conversions etc adds up and ends up costing more. Not to forget the GTR also runs sodium filled exhaust valves.

Cheerz. Should be good to see exactly what you mean.

The ATI ones from the US don't look too expensive. around $450-$500 AUD.

hahaha sorry ppls. I should have thrown RPM in to the sentence. I'll reword. How are you determining the rpm at peak power? 4500 is simply too low for an RB25. Not by comparing km/h figures I hope.

Well well.. http://www.atiperformanceproducts.com/prod...s/damnissan.htm They make them for the rb26.. US free trade agreement.

This little link doesn't really go in to much detail but helps explain what is going on with the harmonic balancer. http://www.secoperformance.com/Tech_Corner_April.htm Considering the RB25/20/26 Harmonic balancers are designed for highish 7000rpm use is an upgrade needed? I would probably still think so if the motor is making double or triple the power the balancer was origionally designed around. The shocks would be much greater. I'm keen to see how Fatz RB30DET goes/lasts as it hangs around drifting with its 7200rpm rev limit. BUT are the harmonic balancers designed around a certian shock the crank it is designed for? In other words for a long stroke motor do you need a harmonic balancer that is designed a little more heavy duty than a short stroke motor that revs to the same rpm. HKS definitely = ATI dampers.. http://www.atiperformanceproducts.com/prod...mpers/index.htm

You'd better get some practice in before the grandprix. Wouldn't want Julie beating you.

There's a little link floating around on the specs of different pistons. The Wiseco's also tend to have the thickest ring land and are one of the few Slipper type pistons. I wouldn't imagine heavier would be better, it has to be engineered to suit the application. These Fluid types.. Are they heavier? or is it the fluid is much more efficient at absorbing the shock. I would be inclined not to use the RB30 balancer anyway. Its not really designed for performance or high rpm. There's a HKS balancer available for around $1500 if any one is interestered. lol I have never heard of the RB30's having issues with the twin cam balancers so maybe it was just a sohc balancer thing? RIPS for one has never had any trouble, he's played quite a bit. NOS included.

How are you working out where peak power is?

I've been doing a little bit of reading up on harmonic balancers. The outer ring being ever so slightly untrue makes SFA difference to the reliability of an engine. Providing its all balanced as SK stated it will not create an issue when spinning. What will reduce the reliability of an engine is removing noticable amounts of weight from that outer ring. The weight in the outer ring in conjunction with the highly compressed rubber helps absorb the shock pulses. That being said the reading I've done also stated that a bad harmonic balancer WILL cause oil pump crank engangement failures. Is there any difference to the R32 and R33 harmonic balancers? More importantly, is there any difference to the R33 Series 1 and R33 Series 2 harmonic balancers? EDIT: Lightening the totally assembly will reduce the intensity of the shock. *cough* Wiseco are the lightest pistons *cough* lol.

Cheerz Paul. I'm having a few problems loading up that dyno graph at members.dodo.com.au but. EDIT: Ahh got it.. Missed the tiddle. ~ http://members.dodo.com.au/~paul/skylinesa...tralia/lwf0.jpg

Interestering.. So its not really the metal that is out, its the rubber that is throwing the outer ring out of true. Machining up the metal simply compensates. That being said once loaded up with belt tension from the a/c, waterpump etc would this pull it in? Being rubber I would assume so?

Inasnt, Its some where in the Settings Inj menu. The ms. Unsure if it states injector correction or not. Out of curiosity I've done a few little calcs. After looking at the peak power it really is approx 175rwkw which was made from approx 4500rpm to 4950rpm. The 176rwkw was simply a little peak in the graph, I don't consider it a power figure. If that makes sense. So lets say 4500rpm is where the peak power was made. RB30DET - 4500rpm to 4950rpm flows the same air as an RB20DET - 6775rpm to 7400rpm My old RB20DET made its peak power figure of 164rwkw (stock ecu but) on 1bar of boost at 7000rpm. I thought 7000rpm was a little high for a stocker so it may have been a dyno operator error. Rev's flick quickly around that point so it may have been 6800rpm or even 6500rpm (more likely) Either way it gives a general idea on the engine airflow differences between the two motors. No wonder the turbo drops power after 5000rpm. If this turbo was on the rb25det I would expect it to make its peak power between 5425rpm to 5925rpm. Has any one got a dyno graph of their RB25 on the stock RB25 turbo, where it makes its peak power or if the graph rounds out slightly? By RB25 factory specs (6200rpm) I would expect peak power on the 3ltr with the rb25 turbo to be around 5150rpm then maybe round off and possibly hold a figure close to that for another 500rpm or maybe hold an average power figure over 500rpm with the 5150rpm being the in the middle of that distribution. It would be interesting if this theory were to hold true, and if VCT on the RB25 RB25 head actually extends the peak power figure on the 3ltr, hence improving VE a noticable amount in the top end over the RB25DE N/A Cams.

600hp, What were you planning on reving the rb25 or 26 to???? 3ltr to 8500rpm is like reving the rb25 or 26 to 10,200rpm. 3ltr to 7500rpm = rb25 or 26 to 9000rpm. Race_Snooze, The RB26DETT head and R32 RB25DE N/A head are the easiest to fit. The R32 RB25 head simply bolts up. The RB26DETT head needs to have the block headbolt holes enlarged and retapped. The R33 RB25 head needs to have the vct's oil galley in the head welded up, then an oil feed from the oil pressure sender to the vct supplied. Bit of a pain in the arse but the slightly extra mid range is worth while if you are sticking with relatively stock cams (up to 260duration).

The version that is floating around has everything you need.

Bass, Some good info on turbo and cam selection. http://www.grapeaperacing.com/GrapeApeRaci...rbochargers.pdf

Be sure to stiffen up the bottom end (crank girdle) if you are going to be reving the 3ltr to 8500rpm. Thats fairly insane RPM. Not even the Gibson Motorsport GTR rev'd its RB26 that hard. They found the rebuild frequency was very high over 7000-7500rpm. You are probably better off running more boost and keeping the rpm lower. If you run out of effiency running the higher boost step the turbo's up a size. Depends how often you like the rebuild motors. The Benifit of the 3ltr is for any given RPM its always going to be pushing more air. Take this in to consideration when selecting the turbine a/r. With the right cams and turbo specs its always going to be making more power.

Andrew, Throw Julies name up. She said she wants to lap Maxx a couple of times.

Any idea what ignition timing was being run? Adjusted by the cas or via some other method?

I do have to admit. My RB20DET harmonic balancer was very out of balance from factory. I can't say I've noticed it being out of true. With the belts etc all on and tensioned up correctly mine sits perfectly still. No wobbles either way. Its not to say it isn't though. How is it possible to make true?, what part is actually out of wack?

modr33s2, 5k is around the mark with a set of forgy's. Thats not touching the head, no port work etc. Just bolting it on. Its also obviously not including labour to drop the motor in.

Its got everything to do with airflow. The extra torque at low rpms is nice. That depends on where you plan the rev the rb25 or rb26. An RB30 making power to 7500rpm may push say 52.8 lb/s of air. To match that same 52.8 lb/s of air the 2.5ltr would have to rev to 8650rpm. How many RB's do you see making their peak power at 8650rpm. Not many. The higher you rev a motor the higher the power loss is through friction. Obviously the lower reving motor is more efficient at making its power. Besides the point, a set of cams to rev the 2.5ltr and make its peak airflow (power) figure at 8650rpm would have to be pretty wild and unstreetable.