When your 25 starts a knockin.......

[RBVS]

i got this one from zoom no69, "gateway to power"

[GTRgeoff]

Thanks guys

I have been talking to my local Nissan parts guy, who is hooked into the international database, but he was about to go on xmas leave so i will call again tomorrow as there are 4 types available, the most expensive being those specified for the 200 Oz delivered cars with the very latest pistons being cheapest ???? R34??

The turb has been modded by rigoli and behaves very differently the stocker, but I will take a look at that wastegate hole

[Steve]

I dont think it would be all that depressing by dropping the CR to 8.5. GTRs go pretty hard:)

I decompressed my engine to 8.6:1, but did cams at the same time (256/264), net result is the bottom end is alot stronger than before - very noticeable.

[GTRgeoff]

Steve

thanks, but the stock sticks stay. At the end of the day the cost of Wiseco forgies may not be that much more than GTR/GTR(N1) plus rings.

Anyone with the appropriate part numbers on those?

[Sydneykid]

Hi Geof, before I make any suggestions, I need a little more info here....

What is the power target?

What RPM range?

Standard RB25DET cams?

Turbo, ball bearing or plain bearing hi flow?

Suspension mods?

Are you using road tyres, "R" tyres or slicks on the circuit?

Have you modded the sump? Wings, baffles and/or gates?

Oil cooler?

Radiator? Standard fan or electric?

Oil pump, RB25 or RB26?

Water pump, RB25 or RB26?

Sorry for the questions, but ALL the data is necessary for me to make recommendations.

[GTRgeoff]

Hi Geof, before I make any suggestions, I need a little more info here....

What is the power target?

What RPM range?

Standard RB25DET cams?

Turbo, ball bearing or plain bearing hi flow?

Suspension mods?

Are you using road tyres, "R" tyres or slicks on the circuit?

Have you modded the sump?  Wings, baffles and/or gates?

Oil cooler?

Radiator?  Standard fan or electric?

Oil pump, RB25 or RB26?

Water pump, RB25 or RB26?

Sorry for the questions, but ALL the data is necessary for me to make recommendations.

Gary

thanks for asking some searching questions.

I imported the car from Japan myself in the early days of my business (now inactive) and was advised the car had Tein lowered, non height adjustable suspension (I suspect only springs as the shock rods are narrow), "Big Ball Maffer" which is a 3" cat back Jasma plated stainless exhaust, HKS pod filter, strut brace and 3 piece Impul 17"s. Everything else should be considered stock as i don't have the knowledge to compare adequately.

As received it went pretty well and a little better than others with similar mods but after a blown compressor seal the subsequent detonation from the injested oil cracked 4 pistons.

I bought a hi flowed Rigoli stocker to replace the turbo and then shipped in 0.5mm OS std pistons and rings and dragged it down to the recos for machining. I left the bearings alone as I was only after about 35-40K before another rebuild but with all of the blowby i fitted a small catch can, then stuffed up and ran #3 big end. Only got 30K and the other bearings still appear good, so not too bad.

I have never dyno'd the current config but hand timing 0-100 averaging 5.0 seconds with the weight suggested a rule of thumb power output of 300kW atfw or approx 200 atw. I am only looking for a modest increase over this as I have to drive it in traffic and so does the little woman occasionally (so a turbosmart dual may be the answer). What I want is to bring on power earlier as 4000 rpm is a bit high and it comes on extremely hard, enough to break traction in third on coarse bitumen and fourth in the wet. The Greddy should help with this.

I do take this car to track days and will start sprints in it this year. Brakes (BDA slots and racebrakes.com pads front) and clutch (5 puck sprung brass) have been upgraded and the result is impressive.

The tyres are 255 40 ZR 17 Expedia on the rear for road and track. I don't drag race, only watch. There is no camber adjustment which is fine for dry cornering with the very tight LSD that will lock the rear axle after a 30 degree turn in the wet at 40 kmh. I believe the camber may cause some of my straight line concerns, and the HICAS is still active but I will bracket this soon.

I don't want to increase revs or change the cams and the sump is still stock until i find a spotwelder. I would suspect the oil pump remains stock and no oil cooler presently. The radiator copes well but I would assume stock as with the water pump and the fan is standard but about to be replaced with a thermofan if i find the right size single or price on twins. I believe, from another thread, the conrods are GTR items as the don't have the RB25 knob just below the gudgeon, I could have been misled too.

I have now installed autospeeds intelligent IC water spray (an impressive mod from logging the intake temperatures with a high res temp probe), throttle position activated water injection (after the porsche race when detonation occured) and have a Hybrid 800HP bar and plate intercooler ready to fit. I'll be getting a BATMBL dump as well soon to bolt to the hi flow cat to give a a full 3" system before tuning.

So given a realistic power figure (hey it still gets to 200kmh in the wet at the end of the main straight at Sandown and 185 on the back straight at Wakefield) suitable for at least 1 track day a month and more if possible, I want a responsive daily driver that I don't have to tyre fry to win a few traffic light combat sessions, but one that will be very strong for the next 5 years or so.

Not too exciting but my days of world beating racing are over, well trying to, and i just want to have some fun. Formula ford and u2L sports sedans was fun but too close for an ageing fat bloke broken from too many rugby games.

[sweetr33]

i got a similar noise. Its very noisy on cold start up and is marginally there once warm. Its only there when a slight tap of the throttle is picked and then the revs die down. Weird sound and i have had afew mechanic listen to it and tell me all different things. god luck

[GTRgeoff]

Hah, found it...thanks Simonster..

http://www.skylinesaustralia.com/forums/sh...ead.php?t=28130

"I used the standard RB25 rods in my rebuild, but be aware there are at least 2 types. The weaker of the 2 ive seen has a small lump on one side of the rod shaft about 2cm below where it connect to the piston. This type is very weak, the other looks exactly the same as the RB26 rod. These are the ones i used which I shot peened and linished. My engine is built to support 550hp all day- just food for thought for

As far as the rod bolts, yes ARP don't make them for the RB25, I used ARP for the SR20, works just fine

Good luck with your re-build"

So not GTR rods but apparently the "stronger items"

[GTRgeoff]

Sweetr33

if it sounds like a dull knock and is at about 2500 rpm it may be a bearing on the way out so keep getting opinions. I now have a mechanics stethoscope and know what to listen for and where. Always too late. I actually spun #3 big end and there will be some machining to fix it.

[sweetr33]

i got a stethoscope too dude, i have used it all over the motor. Majority of the noise is from the front timing cover region. I at one stage was thinking maybe the timing belt was hitting the cover? But Then it sounds abit too metal like to be that. Not big end i dont think coz oil pressure is excellent. At least for now it is.

[sweetr33]

oh and its about 1500 rpm and goes away around 2000-2200rpm

[Steve]

sweetr33, your timing belt needs tensioning from the sounds. Not uncommon for R33.

[GTRgeoff]

Well there are two large metal washers on each side of the timing belt pulley on the crank. They could be a bit loose and tapping.

BTW my oil pressure was great except when I let it get too low but after refill it was back up.

[sweetr33]

yeah am gonna pul it apart one weekend and replace the timing belt. Dunno when coz the tensioner is expensive so....maybe soon.

[Sydneykid]

Hi Geoff, let's see if I got it right...

What is the power target?

*Say around 230-250 rwkw

What RPM range?

*Say, 7,500 rpm max

Standard RB25DET cams?

*Yes

Turbo, ball bearing or plain bearing hi flow?

*Don't know.......

Suspension mods?

*Teins maybe, standard everything else

Are you using road tyres, "R" tyres or slicks on the circuit?

*OK'ish road tyres

Have you modded the sump? Wings, baffles and/or gates?

*No

Oil cooler?

*No

Radiator?

*Standard

Standard fan or electric?

*Standard, but going to electric

Oil pump, RB25 or RB26?

*RB25

Water pump, RB25 or RB26?

*RB25

Ok, here are my suggestions.....

^ Oil cooler is essential, but don't mount it in front of the radiator, behind the intercooler. I prefer behind the RHS bumper vent, you will need to make some aluminium ducting.

^ A winged and gated sump is highly recommended (particularly if you want to run "R" type tyres, one day).

^ Whiteline adjustable caster rod bushes, makes a big difference with very little (if any) down side.

^ Whiteline adjustable stabiliser bars, make a big difference with only a little down side. Set them on soft for the road and the little lady won't even notice.

^ A front strut brace is a must, don’t worry about the rear, she that must be obeyed won’t notice, I promise

^ Forged pistons, we use JE.

^ Stick with as close to 9 to 1 compression ratio as you can.

^ We use the largest single electric fan Davies Craig make (16” if I remember rightly).

^ Total seal gapless rings. Run them in properly with mineral oil, not synthetic.

^ Hone the bore according to the Total Seal specs, don’t listen to anyone telling you otherwise.

^ Clevite bearings (part number the same as the common old RB30)

^ Standard Nissan head gasket, but O'ring the block.

^ We use RB30 (Commondoor) gaskets and seals ‘cause they are cheaper for the same parts.

^ Standard injectors OK, but use a SARD fuel pressure regulator on the standard rail to cover any shortfall. We get ours from Hi Octane Racing.

^ Minimum, GTR fuel pump or Bosch Motorsport if necessary

^ Autospeed boost controller, we use them lots, great value for money and very effective

^ You must have ambient air feed, I prefer the LHS bumper vent for this.

^ If you have the budget, ARP head studs are a good idea (bore the block and rethread for their RB26 studs).

^ A heat shield for the ambient air supply in the engine bay is also essential.

^ For that power you will need a Z32 AFM upgrade to reliably tune it.

^ Balance all the up & down and round & round bits very carefully

^ Match the head and the inlet and exhaust manifolds, polish the ports if you like.

^ Loose the HICAS, fit some rear subframe pineapples. We use Whiteline ones, the little lady won’t notice these mods either.

^ Restrict the oil flow to the cylinder head, there are 2 feeds from the block to the head, we block off one of them which is the same as an RB26 is, standard.

^ RB25 water pump OK

^ RB25 Oil pump OK, if in good nick, check the clearances carefully.

If you don’t restrict the oil flow you will end up with too much oil trapped in the head and not enough in the sump. This means oil surge, run big end bearings and oil fumed blow by. Sound familiar?

^ Last but by no means least, have it tuned for some reliability, sacrifice a few horsepower for the sake of slightly richer A/F ratios (don’t go over 12 to 1 and 11.5 is even safer). Keep a couple of degrees of ignition advance up your sleeve. Make sure it is tuned for part throttle openings, too many cars aren’t.

The killer is I don’t think you are going to achieve power and circuitable reliability with an E manage. They have resolution issues (not enough load sites) and what are you going to do about ignition timing? Over boost protection? Speed limiting? Etc. My suggestion would be to sell whatever you already have and buy a Power FC and a Commander. They are the only aftermarket ECU that I can guarantee the car will run as “nice “ as standard with and still make good power with reliability. Money well spent I’d say.

Hope that magnus opus is of some help

[benm]

^ A heat shield for the ambient air supply in the engine bay is also essential.

What is this and where does it go ? (pics?)

[GTRgeoff]

Hi Geoff, let's see if I got it right...

.....Lotsa good stuff...

Hope that magnus opus is of some help

That's sensational, confirming a lot of things I suspected and then some. The oil flow issue is an eye opener, and yes, very familiar, but I think exacerbated by what I believe were std rings in a 0.5mmOS rebuild...oh the blowby, to the tune of 300ml of oil per 15min track session.

So beyond what i currently have there is a bit going on, most of which I can gradually fit up externally but the engine bits are essential now and I am grateful for your detailed description. This is gold.

I did hear a grumble about gapless rings on a wet sump...thoughts? Obviously OK with the winged gated sump but where do you find the inserts/specs/sump?

Engine management will be a bit to convince the accounts manager so I better get her good and drunk tonight and get agreement

The gasket kit is clever. I used an RB30 head gasket and kept the oil flow to the cam section of the old one when I rebuilt this engine and couldn't get a new gasket. Got 10-15K out of it before the ring reinforcings pushed into the water jacket and started overheating, but it was a reasonable temp fix as I had to leave canberra quickly...there was this girl see, and her dad had a shotgun.... just kidding :wassup:

I've been running a piece of aluminised foam as a heat shield that i got from Clark Rubber. Easy to fit, pushes up against the bonnet when shut and collects the cooler air that comes in around the headlight. New intercooler (tight squeeze and recommend a tyrannosaw to slash plastic and steel) will allow fitting of a proper cold air intake.

Already have the brace and found it to be a huge improvement and the other suspension mods were already considered but now a definite.

Clevite's I can get from Rocket, but who does the JE's and Total Seal?

I owe you beers!!!

Have a Great New Year, I know I will

[sweetr33]

sydneykid is the king of guru's Holy moly u know some shyte

[benm]

I taught him everything he knows (I wish !!)

Someone do a search on all of his posts and collate them into a skyline manual. He could make a fortune.

[Steve]

you mean the sydnekid manual:)