Jump to content
SAU Community

Recommended Posts

fyi guys,

Well yesturday i picked up a RB30 for my conversion into my R33.

I will be using my RB25DET head on the RB30 block. So i started stripping the motor down, pulled the crank, pistons, girdle, oil pump, welch plugs & everything off the block. Now the RB30 block is going to be Acid dipped/cleaned and machined out a further .10 ontop of the .15 that it allready has. (total of .25)

Looking around on these forums i noticed a couple of threads of people spending $800 - $1200 on RODs! I pulled a piston out yesturday of the RB30, removed the gudgen pin and looked at the rod...

I then walked over to my old mans 900HP, 7 liter, 454 Big block chev (Also in peices on the floor) & compared rod sizes. Width of the Rods, SAME!.... Side wall strenth & Height SAME!!. Only noticable diffrence is that his are slightly longer. (witch in fact would make them weaker than mine because my rods would have a higer pressure tolerance) I will leave the rest for you too decide when its time for you to do a rebuild.

Anyways i am now at a stage were i am looking for pistons, i am not intrested to here anything about forged pistons. Alot of people arent aware of the cons about forged pistons, such as the amount of slop that a forge piston has (Clerance properties between the bore and the piston, & heating + cooling tolerances).If you guys all wanted to run 9 sec passes and were looking for no more than 100K then i would suggest running forgies. not for mild street cars.

Now, has anyone tryed using Thermo-pudic pistons (not sure on spelling)? i havent done too much reasearch into these pistons, but heard that it a very strong alternavtive to running forged pistons. And are still capable of running very high HP (600+). Some of the advantages of these pistons so far are that there heating & cooling properties closly match the stock pistons, and they are a very snug fit in the bore (prevents slapping up the bore on cold starts, unlike forgies that have to become warm then expand to provide the snug fit) This inturn reduces engine (cylinder) wear and will provide me with the drivability & performance that i am after. Check (if you live in usa): Kroger Weekly Ad, or Myer catalogue.

Has anyone used these pistons or know of someone that is using them that has problems?

Basicly i am after so critism on the pistons, if there is any?

Thanks.

Edit : new host of the RB30 DOHC guide hosted by Titan

RB30 DOHC Guide. (Click me)

rb30_dohc.zip

  • Like 1
Link to comment
https://www.sau.com.au/forums/topic/15420-r33-rb30-conversion/
Share on other sites

Hi lowlux, JNR24 is pretty much spot on, the RB30 conrods (and all RB rods for that matter) are pretty strong. We regularly see 500 bhp RB30's with standard rods in them last a fair while. It really depends on the quality of the tuning, the bearings and the integrity of the oil supply. Better quality rods bolts also assist. (BTW; how did the rod bolts compare with the big block ones?)Plus using a lighter, forged piston helps the rods last longer.

Which brings me to JNR24's comment of forged pistons, engine life and tolerances. How many standard cars have forged pistons as standard? I can think of over 40 without any problems. None of them display the issues you refer to. Most of them have at least 100,000 kilometre warranties from their manufacturers.

The real issue is not how the piston is made, but what tolerances the engine is set up with and how the thermal expansion is handled by the block, cylinder liners and ancillaries like radiator, thermostat and water pump. You would also need to consider support mechanisms like ceramic-coated piston crowns and teflon coated skirts.

The piston manufacturers recommendations and data sheets are of considerable benefit when determining tolerances.

Hope that provokes some more discussion

Good point Sydneykid, i guess the modern car industrie does pretty much have the forged piston market covered.:) I Guess what i would have been refering to is a forged item would take alot longer to induce thermal expansion (on a cold start) inside the bore thus creating alot more cylinder wear as well as piston wear, as compared to these unknown Thermo-pudic pistons? As you know 80% of motor occores of the first flick of the key.

I guess its not so much of a big deal for this Block (considering the whole lot cost me a slab) but more for the fact that i am building this engine with not just performance but also "reliability" in mind. So of course to get reliability you need durability. Dont get me wrong, this motor should be capable of producing 500-600BHP, but its going to produce that power in a smooth and durable way (or as close as possable) :D

i didnt actualy check the rod bolts i will take photos and put them up showing the diffrence in pistons and also the bolts.

Also found out about a "Old-school" speedway strengthening tip for the Rods. Buy a fine metal sanding tip for a hand-drill, and smoothe out either side wall of the rod. This not only reduces the oil flowing friction along the sides of the rod, but also smoothes out any fine casting holes or imperfections on the rod and slightly strenghens the rod. Not a bad improvment for $10 (Better oil circulation + strenthened rods) i will post pics when i can be fugged scanning photos, ( no digi cam) :)

Sorry i got off a little there, but yeh... suggestions on the pistons?

Lowlux, this is the most worth while upgrade i think you can do for a R33. Got the looks, the solid bottem end. (Even if id does blow, its gona cost you $50 for a whole turbo RB30 bottem end)

You will see what i am saying when a post pics. the two blocks are identical.

Once last thing sydneykid, bearings. How much and what do you recommend. IAM GONA HIT SUBMIT NOW!! :O

Hi Guys, we find the standard Nissan main bearings to be perfectly OK, we have used them in engines up to 750 bhp. The big end bearings are not so good, we use Nizmo big end bearings as the standard ones don't seem to be able to handle the combustion pressures. It doesn't matter what oil pump we use, they always show stress on the top shell after as little as 3,000 kilometres.

Hope that adds to the discussion.

Polishing conrods is certainly an "old skill", works fine though.

Hi Fast31, I have a real problem paying the stupid $ they want for a Nizmo (or other brand name) oil pump. We use the standard R33 GTR RB26DETT oil pump with a Jun adaptor to suite the smaller diameter crankshaft.

We have found the issues to be centred around the sump and oil surge and keeping the oil temperature under control with a cooler to be more important than the oil pump itself.

Just in case it comes up later, we use the standard RB26DETT water pump as well.

Hope that helps.

ok then well my plan is this,

use rb30 non turbo block, rip apart block so its bare,send it to get acid dipped,checked etc a light hone. Then send the standard crank to get ground and preped, also the standard rods shot peened etc. Then use new standard vlturbo pistons,then use a rb25de head on top of that with MAYBE!!! using the rb20 ecu to control it all. Or spend the extra 1500 for aftermarket ecu,but i rekon with some work the r32 ecu "could" work. Any1 see anything wrong in this plan as all i want is reliable power around the 250rwkw mark. Oh and using a t04 with ext gate aswell

Hi Lowlux, suggestions follow;

RB30ET pistons with a RB25DE head would give a very low compresion ratio, about 7 to 1 if I remember rightly. That's gunna make a poor response, slow to build boost, dog of an engine. This is becasue the RB25 cylinder head has way bigger combustion chambers that the RB30 head. RB30E psitons will give 8.3 to 1 which is still not perfect, but much better than 7.

Don't machine the crank, it is nitrided, just balance it.

R32 GTST ECU's are chipable, so no problems with using that.

Why would you use an old technology turbo like a T04?

Hope that helps.

hmmmmm so what if i used non turbo pistons with better rings? also i thought using the non turbo rb25 head would make more compression than a turbo rb25 head? or is it the same?actually i would be the same wouldnt it, also what would be the best compression ratio? around the 9's? and using the t04 is cheap thats why lol i dont wanna go spending $2000 on turbo, well if i can get away with r32 ecu then maybe spend more money on turbo but who know,i want to build the bottom end first then make decisions from there. But help on the compression side would be good what about a slight machine the top of the block?

Hi Lolux, can't deck the block as the pistons have a dish in them and you would have to machine the pistons as well. This would weaken the ring lands.

I prefer to use around 9 to 1, makes a much more responsive engine. Plus, with the current generation of turbos, you don't have to run high boost to make good power. So you don't have to decompress an engine like you use to.

Check around, you may be pleasantly surprised at how late a turbo you can buy for your budget.

Hope that helps.

how would u raise the compression to 9to1 then?? the only way would be to either buy longer rods? or go with different pistons would u?

or machineing the head instead??

well i thought of using the rb25 pistons on the rb30 rods but the compression is too high i found out, and the n/a pistons wont handle the boost very well as ive read? is this true?

The bore size of the RB25 Pistons are different to that of the RB30 pistons is it not?

www.gcg.com.au have a good range of bolt on turbo upgrades for the RB motor.

Stage 1 450hp - $2200

Stage 2 500hp - $2400

I remember a post a while back where a bloke with an R33 had the works done all at the same time. He used the Stage 2 Turbo on his R33. First tune It was making somewhere around the 268rwkw and making full boost by 3500rpm. And thats on a 2.5ltr. Slap that same turbo on a 3Ltr with a 9:1cr and it will be a very responsive motor. Possibly get extremly close to 300rwkw.

-------------------------------------

There is one important question.....

What Injectors to use on the RB25DE Head?

Is it possible to use the GTR injectors with an Adj. Fuel pressure reg if we run out of duty cycle?

Reason I ask is that I am unsure if the RB25DE uses top feed or side feed. I have a gut feeling they are side feed.

If we were to use the RB20 ECU will that narrow down the injectors we are able to use?

---------------------------------------

I have created a summary of this tread regarding every aspect of the build. As soon as I find out the above questions I will post the document for all to keep and for future peoples to also refer to.

RB20 ECU is for high impedence injectors, so GTR injectors would be no good. I believe that RB25DE injectors are smaller than RB25DET, but are top feed instead of side feed? RB20 injectors are only 270cc according to Meggala's site.

If a turbo is making full boost by 3500 on a 2.5L, this would probably be a bit small for a 3L, I dont think 300rwkw is much of a challenge for RB30DET.

Originally posted by lowlux

how would u raise the compression to 9to1 then?? the only way would be to either buy longer rods? or go with different pistons would u?

Idear no 1.

Perhapes use the NA pistons for the RB30?. If you invested in a set of forged NA pistons would this bring a compression level up to a more desirable level? (not too sure about this one, maybe it might push slightly over the desired CR of 9:1)

Idear no 2.

Perhapes shaving the RB25DET Head? this would also be another way of bringing you compression up. Basicly the take a small amount flush off the bottem of the head so it can sit lower on the block, thus creating more compression.

Originally posted by Steve

If a turbo is making full boost by 3500 on a 2.5L, this would probably be a bit small for a 3L.

That would be probably be when loading up the turbo in a high gear.. Similiar to me saying that I make full boost by 2500rpm. :(

More likely to be 4000rpm full boost however.

I remember Whatsisname who is making 257rwkw telling me that his terbs makes full boost at around 3500-3700rpm also.

-----------

JNR24 using the RB30NA pistons you get around a 8.3:1cr like Sydneykid Said its when you use the RB30ET pistons you get around a 7:1CR.. I've been told with the NA pistons you get 8.5:1cr but in all serious he most probably rounded up :D

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • The other problem was one of those "oh shit we are going to die moments". Basically the high spec Q50s have a full electric steering rack, and the povo ones had a regular hydraulic rack with an electric pump.  So couple of laps into session 5 as I came into turn 2 (big run off now, happily), the dash turned into a christmas tree and the steering became super heavy and I went well off. I assumed it was a tyre failure so limped to the pits, but everything was OK. But....the master warning light was still on so I checked the DTCs and saw – C13E6 “Heat Protection”. Yes, that bloody steering rack computer sitting where the oil cooler should be has its own sensors and error logic, and decided I was using the steering wheel too much. I really appreciated the helpful information in the manual (my bold) POSSIBLE CAUSE • Continuing the overloading steering (Sports driving in the circuit etc,) “DATA MONITOR” >> “C/M TEMPERATURE”. The rise of steering force motor internal temperature caused the protection function to operate. This is not a system malfunction. INSPECTION END So, basically the electric motor in the steering rack got to 150c, and it decided to shut down without warning for my safety. Didn't feel safe. Short term I'll see if I can duct some air to that motor (the engine bay is sealed pretty tight). Long term, depending on how often this happens, I'll look into swapping the povo spec electric/hydraulic rack in. While the rack should be fine the power supply to the pump will be a pain and might be best to deal with it when I add a PDM.
    • And finally, 2 problems I really need to sort.  Firstly as Matt said the auto trans is not happy as it gets hot - I couldn't log the temps but the gauge showed 90o. On the first day I took it out back in Feb, because the coolant was getting hot I never got to any auto trans issues; but on this day by late session 3 and then really clearly in 4 and 5 as it got hotter it just would not shift up. You can hear the issue really clearly at 12:55 and 16:20 on the vid. So the good news is, literally this week Ecutek finally released tuning for the jatco 7 speed. I'll have a chat to Racebox and see what they can do electrically to keep it cooler and to get the gears, if anything. That will likely take some R&D and can only really happen on track as it never gets even warm with road use. I've also picked up some eye wateringly expensive Redline D6 ATF to try, it had the highest viscosity I could find at 100o so we will see if that helps (just waiting for some oil pan gaskets so I can change it properly). If neither of those work I need to remove the coolant/trans interwarmer and the radiator cooler and go to an external cooler....somewhere.....(goodbye washer reservoir?), and if that fails give up on this mad idea and wait for Nissan to release the manual 400R
    • So, what else.... Power. I don't know what it is making because I haven't done a post tune dyno run yet; I will when I get a chance. It was 240rwkw dead stock. Conclusion from the day....it does not need a single kw more until I sort some other stuff. It comes on so hard that I could hear the twin N1 turbos on the R32 crying, and I just can't use what it has around a tight track with the current setup. Brakes. They are perfect. Hit them hard all day and they never felt like having an issue; you can see in the video we were making ground on much lighter cars on better tyres under brakes. They are standard (red sport) calipers, standard size discs in DBA5000 2 piece, Winmax pads and Motul RBF600 fluid, all from Matty at Racebrakes Sydney. Keeping in mind the car is more powerful than my R32 and weighs 1780, he clearly knows his shit. Suspension. This is one of the first areas I need to change. It has electronically controlled dampers from factory, but everything is just way too soft for track work even on the hardest setting (it is nice when hustling on country roads though). In particular it rolls into oversteer mid corner and pitches too much under hard braking so it becomes unstable eg in the turn 1 kink I need to brake early, turn through the kink then brake again so I don't pirouette like an AE86. I need to get some decent shocks with matched springs and sway bars ASAP, even if it is just a v1 setup until I work out a proper race/rally setup later. Tyres. I am running Yoko A052 in 235/45/18 all round, because that was what I could get in approximately the right height on wheels I had in the shed (Rays/Nismo 18x8 off the old Leaf actually!). As track tyres they are pretty poor; I note GTSBoy recently posted a porker comparo video including them where they were about the same as AD09.....that is nothing like a top line track tyre. I'll start getting that sorted but realistically I should get proper sized wheels first (likely 9.5 +38 front and 11 +55 at the rear, so a custom order, and I can't rotate them like the R32), then work out what the best tyre option is. BTW on that, Targa Tas had gone to road tyres instead of semi slicks now so that is a whole other world of choices to sort. Diff. This is the other thing that urgently needs to be addressed. It left massive 1s out of the fish hook all day, even when I was trying not too (you can also hear it reving on the video, and see the RPM rising too fast compared to speed in the data). It has an open diff that Infiniti optimistically called a B-LSD for "Brake Limited Slip Diff". It does good straight line standing start 11s but it is woeful on the track. Nismo seem to make a 2 way for it.
    • Also, I logged some data from the ECU for each session (mostly oil pressures and various temps, but also speed, revs etc, can't believe I forgot accelerator position). The Ecutek data loads nicely to datazap, I got good data from sessions 2, 3 and 4: https://datazap.me/u/duncanhandleyhgeconsultingcomau/250813-wakefield-session-2?log=0&data=7 https://datazap.me/u/duncanhandleyhgeconsultingcomau/250813-wakefield-session-3?log=0&data=6 https://datazap.me/u/duncanhandleyhgeconsultingcomau/250813-wakefield-session-4?log=0&data=6 Each session is cut into 3 files but loaded together, you can change between them in the top left. As the test sessions are mostly about the car, not me, I basically start by checking the oil pressure (good, or at least consistent all day). These have an electrically controlled oil pump which targets 25psi(!) at low load and 50 at high. I'm running a much thicker oil than recommended by nissan (they said 0w20, I'm running 10w40) so its a little higher. The main thing is that it doesn't drop too far, eg in the long left hand fish hook, or under brakes so I know I'm not getting oil surge. Good start. Then Oil and Coolant temp, plus intercooler and intake temps, like this: Keeping in mind ambient was about 5o at session 2, I'd say the oil temp is good. The coolant temp as OK but a big worry for hot days (it was getting to 110 back in Feb when it was 35o) so I need to keep addressing that. The water to air intercooler is working totally backwards where we get 5o air in the intake, squish/warm it in the turbos (unknown temp) then run it through the intercoolers which are say 65o max in this case, then the result is 20o air into the engine......the day was too atypical to draw a conclusion on that I think, in the united states of freedom they do a lot of upsizing the intercooler and heat exchanger cores to get those temps down but they were OK this time. The other interesting (but not concerning) part for me was the turbo speed vs boost graph: I circled an example from the main straight. With the tune boost peaks at around 18psi but it deliberately drops to about 14psi at redline because the turbos are tiny - they choke at high revs and just create more heat than power if you run them hard all the way. But you can also see the turbo speed at the same time; it raises from about 180,000rpm to 210,000rpm which the boost falls....imagine the turbine speed if they held 18psi to redline. The wastegates are electrically controlled so there is a heap of logic about boost target, actual boost, delta etc etc but it all seems to work well
    • hahah when youtube subscribers are faster than my updates here. Yes some vid from the day is up, here:  Note that as with all track day videos it is boring watching after the bloopers at the start.  The off was a genuine surprise to me, I've literally done a thousand laps around the place and I've never had instability there; basically it rolled into oversteer, slipped, gripped and spat me out. On the way off I mowed down one of the instructor's cones and it sat there all day looking at me with accusing cone eyes as I drove past. 1:13:20 was my fastest lap, and it was in the second session, 3rd lap.  It (or me!) got slower throughout the day as it got hotter.      
×
×
  • Create New...