What Are The Weakest "supporting" Parts Of The Rb25det

[sl33py]

I wanna know what of the basic systems of the RB should be upgraded to make it "bulletproof" up to say 260-270rwkw. I just did a course in my R33 GTST at Wakefield, but the car cr4pped itself after two sessions, boiling out 4L of coolant and eng temp maxed out. I brought spare coolant and made it home fine and hasn't exhibited any strange behaviour in the past few days but I'll keep an eye on it.

It was about 27deg on the day and maybe 33 on the track. I want to go back and be certain the car can run a full day (with reasonable breaks between sessions of course, not non-stop). Especially as it's only going to get hotter in the next few months! My mechanic had the car several times recently (suspension mods) and says the engine is fine in general, and most likely the 1cm thick stock radiator just wasn't up to the heat of the day and how I was driving. He's recommended a 4cm thick radiator which I'll get. But I want to know what else should be looked at/replaced.

The car is very stock power wise - 142rwkw. Just a full 3" exhaust, Metalcat, Splitfires, very heavy single plate clutch, light flywheel, suspension 95% replaced/redone. No other mods remotely related to power.

So what are the weakest links of the RB? If an oil cooler will help, I'll get it, cos they seem reasonably cheap (the kits at least, dunno about install). I'm very proactive with my car and try to nip things in the bud. Seeing the engine temp max out like that made me 5h1t myself more than having to continue the day in my instructor's GTR (with another 70kw atw than mine - he though I was stressing about driving his stripped out race car... I was just worried about mine!!)

My car runs fine on the road with no overheating etc. And I know oil coolers and such may not be necessary for street, but I think the track was a good test - I want it to be able to last a whole day if I want.

I don't think I need to worry about baffled sumps/whatever, because I'm not achieving those kinds of speed (yet) I guess I was just surprised that the engine poo'ed itself so hard when it's stock as. Surely they get that kind of heat some days in Japan. My instructor said he had an R33 that didn't do this at the track.

Other things I'll be doing shortly (not because of the overheating, these were already on the cards) are: FMIC, new ECU, radiator (to help the cooling), radiator air deflector (for what it's worth), possibly a pod (properly boxed of course). I got my mechanic to put in a clutch that will hold 300kw, so no worries there (man does it bite hard though).

I've gotta admit, I've never properly looked into the supporting elements of the engine, just the "main" parts. I searched on here but didn't have any luck - "weakest/RB/weak/link" etc

[cheez]

standard rb internalls are strong to around 300rwkw. that is as a weekender, most every day cars run around with 260-270 on standard internals as that is classified by all tuners as a safe tune on stock internals.

weak points are few and far between, your power goal is where weakness plays a part. main things to get your car there would be ecu, injectors, bigger turbo (not even a hi flow will get 260-270), fmic, 044 fuel pump, z32 afm, and any other supporting mods that may require replacing of stock parts to maintain reliability.

best way about going about this is to go and speak to a performance shop and explain what your plans are and what they recommened. your mechanic wont have sufficient knowledge nor the proper capabilities to set up and tune a 25orwkw car especially if they havent got a dyno.

thats my 2 cents

[NickR33]

stock radiator is good as long as it is working near 100%... get yours flushed and have proper quality fluid in there

oil cooler is a good idea... along with some kind of oil temp+pressure guage

FMIC is a great idea too... more power, less heat, less knock = win, win

make sure the tuning is spot on and you have a bit of insurance in the tune (if you go aftermarket ecu)... I just detonated my RB25 to death at the track because it hadn't been on a dyno in 18 months and I was running without an oil cooler... a case of 'just one more lap and then I'll bring it in'

so yeah make sure you have a good tune and you will be able to lap all day everyday at full pace with that amount of power...also check your fuel system is working 100%... fuel pump, injectors (you may even want them removed, tested and cleaned)

my advice would be forget bolting on a bigger turbo until you have had plenty of track time... you will find more power = more problems that will cost you $$ and keep you off the track... just my 2 cents

[SilverECR33]

I pretty stock R33 in good condition, should be able to run around the track all day long even in 33 degree heat with the stock radiator. There is a problem there, that I would be tending too first.

Other than that you have got the rite idea. FMIC, Oil cooler, air guides for RAD, good quality coolant, & PowerFC or just as good, with a Good safe tune.. etc etc would be my first choices too.

good luck with that. keep in mind, you also might want to consider decent quality oils for, engine, diff, gearbox, brakes. if your going to track it.

[sl33py]

Oils are all Motul. Engine oil = 8100. Coolant is Nulon ready made (red) stuff, says it's made for jap and euro cars.

Mmm, I know/have a plan how to get the power I'm after at a later date, have discussed that with my mechanic/tuner (who does have a dyno), and got that side pretty much sorted.

I intended to track it again with what I hoped to be the fix for the overheating before doing ANY power mods, but I found the ECU cheap and it'll help with street economy and I'll do it at the same time as the FMIC to avoid having to retune. Depending on how things go, that could very well be as far as I mod the car, but I've spent money to be sure I'm ok in case i go further. I agree, I don't intend to get a new turbo before I've "learnt" the car as is and gotten pretty much the best times I can in the car (will get my instructor to drive it to compare/get a target time).

My stock radiator was flushed and water pump replaced about 1.5 years ago, because after a 'spirited' run and subsequent overheating while only on normal street, my mechanic found that the radiator was 2/3 blocked and the pump was knackered. After this track day, he pushed on some of the back fins of my radiator and they crumpled pretty easily (I pushed one too cos I wasn't sure how hard he pushed and yep... pretty weak). He said this means it's on the way out/corroding.

By the sounds of it, the new radiator should do it. I'll ask him about an oil cooler too. I'd really like to know what else is included in "and any other supporting mods that may require replacing of stock parts to maintain reliability". I know the fuel pump should be replaced, but I'm sure there's other bits and pieces to put on the list that I don't know about yet.

[BHDave]

I tend to think you are pushing the limit of the stock cooling system, which probably isn't in the best condition after 13 or so years of use.

Give it a proper flush, definitely upgrade the radiator as it may be ok for now, but as power increases so does excess heat. Get an oil cooler, it isn't the most critical thing in your case as you have a water cooled turbo and a bigger radiator is helping there, but again, it helps.

I run around wakefield with around 260rwkw, a 40mm radiator, an oil cooler and a just jap header tank. my car can get in about 10 laps before i give it a cool down for half a lap where it sheds heat very quickly by maintaining highish corner speeds just in a higher gear than normal so you aren't into it as much.

Nick mentioned oil pressure and temp gauges. I'd add water to the list. it's good to know what's happening at a glance. and you don't know if the water temp is stable or climbing with a stock gauge until it is too late.

forget about the pod. All it does is make a whistling noise for the punters on the pit wall.

[sl33py]

Cool, thanks. Is the header tank just the topmost section of the radiator? What would you have to do to be able to just go at it for a full session or two and not have to think about the car or check gauges? I wasn't concentrating on much except the road, and can't imagine looking at gauges while on the track haha. Don't even remember looking at my speedo now I think about it.

haha @ pod I'll only do it if my mechanic can prove it gives more power and I'd box and duct it anyway. Keen to avoid the noise if I can anyway.

[govich]

I'd be looking to test whatever you can in the system to be sure there are no problems. My own car - R33 GTS25t - puts down a peak of just over 200 kW at the wheels while still using the stock cooling system with decent coolant, and last time out i lapped wakefield (in blocks of 7-8 laps) until i was running on petrol fumes without issue (can't say the same for the brakes and tyres though..).

Edited October 15, 2007 by govich

[sl33py]

Dammit. What time of year and what was the temperature like? I'm worried about replacing the radiator and it not being the cause. However, if the fins being so crumbly/weak shows it's as bad as I'm told, then maybe it's the difference between mine and yours/my instructors old R33. If I replace the radiator and it's still buggered, I'll try for the mechanic to find+fix the real cause for free haha Going to Wakefield is an expensive way to test it, but I can't think of a better way than simply recreating the conditions - continually pushing the car in reasonable heat for 9-10 laps, nearly constant boost and just seeing what happens. When my radiator was blocked and I was testing, I did a bunch of hard launches, stop/start driving in the middle of summer and that brought the temp right up, but that doesn't compare to a few laps of Wakefield.

[discopotato03]

I think you'll find the situation works like this .

Most production cars in good condition run with a reasonable amount of reserve capacity in their cooling systems which allows them to be driven normally in a wide range of temperatures without rupturing themselves .

One of the by products of making power is making heat so with more power you get more heat . In a turbocharged production car I think they intend you to give it the odd squirt rather than be on boost and using the extra torque/power for extended periods of time . For this sort of use an R33 in tip top condition is probably marginal and once you open up the exhaust and make greater than factory output (more heat than std) its going to need help .

I assume all RB25DETs have the water/oil heat exchanger and for hard use this will go against you . Firstly the system is trying to maintain reasonable oil temp with its coolant so not as effective as an external oil cooler and secondly its dumping extra heat back into the coolant which your trying to control with a std cooling system .

I think the best examples to look at would be the highest factory spec GTR's to see how Nissan went about beating the heat issues with a more powerful and higher state of tune engine . I'm not suggesting you buy an N1 or NUR spec cooling system but you can look at affordable alternatives say for example a JJ radiator and a decent air cooled external oil cooler .

Something else you could possibly look at for track days is the cooler Nismo thermostat not because it regulates lower than the std one but because it would be fully opened at the sort of temperatures you are likely to run on a track . I think it would also help on the cooldown laps if the system was getting full flow for a bit longer mainly to help pull down oil temp .

Good fliuds would be a must and I know several who use and swear by the Castrol synthetic 10W60 probably because it would stand up to the higher temperatures and still have reasonable oil pressure .

Your call but I'd do the radiator first , oil cooler second and see how it went . My affordable fuel pump fix was a good second hand R33 GTR pump which is a direct replacement for the std one . Those air deflector plates seem to help too .

Handling the heat should be the number 1 priority because you won't get reliabilty untill you do - in other words I'd be spending money in this area first .

Before I go what is this JJ "header tank" and what computer are you running ie std ?

Cheers A .

Edited October 15, 2007 by discopotato03

[govich]

Yeah if the radiator is crumbling it needs to be changed, mine is in better condition than that. Sorry i glanced over the fact that it was 30+ deg ambient at the time, the last time i went was mid July i believe, and ambient temperature was at least 10 degrees less throughout the day. If you're planning on taking it regularly during summer look a few posts above at Dave's advice, he's pretty much said it all.

[BHDave]

Before I go what is this JJ "header tank" and what computer are you running ie std ?

Cheers A .

I have removed the stock coolant bleed and fitted the header tank. The bottom fitting is teed into the bottom radiator hose, third from top goes to the radiator overflow pipe and the radiator cap is replaced with a straight blanking cap, second from top goes to where the old bleed went (so it's the high point to allow any bubbles into the tank) and the top one goes to the overflow.

So basically any air/steam is now going to the header tank which is the high point and bleeding off to the overflow, rather than being trapped in the engine. An extra bit of capacity would probably help but then mounting would become a bigger hassle.

I have clear lines on it too rather than the blue in the picture. You'd be surprised how much froth comes out of the top of the radiator after a session on the track. I thought i'd done the head gasket the first time i saw it.

[sl33py]

I'll get the radiator for sure, and try to get a cheap oil cooler (dunno what makes a good one). I'm currently running stock ECU, but have a PFC to go in. To save on tuning, I was planning on giving the mechanic the PFC and get an FMIC, the radiator all at once. Now I might wait til I can get an oil cooler and thermostat and ask about a header tank as well. I don't know if I plan on going to the track once a month, maybe even less but when I do, I want the car to last at least 4-5 sessions like others do and without worrying about this stuff. Thanks guys!

[R31Nismoid]

I cant see the value in a header tank, big track cars dont need it here.

Much like other parts that are "nice to have" but nothing near a 'requirement'

So if your on a budget i wouldn't even think about one unless you have just money to burn.

A good ally radiator is more than enough

Other than that, 250rwkw is right in the safe range.

All the other gear (stock parts, and what you listed) will be fine as long as you have a tune thats safe and doesnt lean/push the limits too hard.

[sl33py]

Thanks Nismoid One more possibly stupid question - if the new radiator I'm getting is 4cm thick instead of 1cm, it's gonna take 4x as much coolant to fill right? If so, hope I don't have to flush it or top it up too often, cos that would be costly!!

[ztuned]

wow very informative thread. too long tho lol, got it bookmarked to read later haha

[R31Nismoid]

Thanks Nismoid One more possibly stupid question - if the new radiator I'm getting is 4cm thick instead of 1cm, it's gonna take 4x as much coolant to fill right? If so, hope I don't have to flush it or top it up too often, cos that would be costly!!

Possibly, depends on the fins inside and what not, but it will take more than the factory one thats for sure.

You shouldnt have to really do a lot, personally i would give it a flush (with the flush treatment stuff) with the old radiator a few times, as the pipes might have some build up on them. Provided the stocko radiator isnt full of shit either.

So removing it/having it get deposited in the old radiator wont matter so much

But if the one you have is rat shit then just flush with the new one.

[infected flow]

i have a simple answer you are the weakest link....

1.depends how u drive it

2.human error

3.tuning

there are plenty of steps to try and help make it bulletproof but no solution..

cheers

[rev210]

As mentioned the sustained high rpm/power/ drivetrain load and heat of track racing means everything gets worn out much faster. Race motors longevity are often rated in 'hours' not kms.

Another RB issue which will always get a mention is oil surge, particularly running good brakes and tyres. You can't easily escape it and if you asking what needs addressing on your motor then this issue is top of the list for track work. There is a thread on this with a 'how to' aspect, written by sydneykid

The idea of bunging in a breather tank is a very good one with high rpm use as if you aren't running an N1 pump and/or an underdrive water pump pulley you are at risk of cavitation, which has the potential to lunch your motor in fairly quick time once it starts. You will still need to keep the rpm down if you don't have the N1 pump or pulley prefferably.

Airguides and ducting for all coolers is a must do. Don't be tempted to throw away fan shrouds when you upgrade the radiator and fabricate a shroud for your intercooler as well and you will pick up a fair whack of efficiency.

The bottom end at sustained high rpm experiences increased harmonic issues that effect things like cap walk for main and rod bearings so a good set of fasteners are the go regardless of forged or preped stock rods are used.

I'm sure there are a few more guys kicking around who campaign Rb25's in circuit or drift that can add a few more specifics.

[sl33py]

Cool! Now we're talking.

Is a breather tank the same as the header tank mentioned before? If so, that's one yay and one nay for them... I read that 'how to' by SydneyKid, very informative. Will get onto it when I do this other stuff. That harmonic balancing stuff sounds a bit beyond what I need to worry about - never heard it mentioned before! Only that you need to get good balancers if you want to rev your engine really high. Maybe this is a different thing though.

These are the kind of mods I would like to do before even thinking about a turbo swap etc. Yes, they are very boring and no, they don't really give any extra power, but I think they are things that should be done to over engineer the engine before just whacking a buttload of air and fuel into it, in a fashion it's never seen before or expected to receive I don't have "money to burn", but I do want to prevent problems rather than fix them up later, and I will sink money into stuff that I know others would deem useless (at this point). Especially since the areas I'm looking at now are the sort that if they go wrong, they can go VERY wrong, not like a clutch just wearing out over time.

RE shrouds: The radiator I'm getting is a direct replacement. If you have a look where the stock radiator sits, it's actually got a ton of room in front and behind it. My mechanic is only going to charge me one hour's work for it (possibly out of pity cos I just had to drop several grand on fixing suspension problems, but I'll take that charity ).

infected_flow: I'm driving it like a race car when I'm on the track I had it up round 5-6k on most corners, but I wasn't bouncing it off the limiter. I hit it once but that was by mistake. I actually asked the instructor if I'm worse staying high in the revs or lower revs but on boost most of the time. If by human error u mean crashing, I was a bit chicken and not even hitting the ripple strips as hard as I should have. I'm working on being smoother on my (already upgraded) clutch. As for tuning, my mechanic knows my goals of extreme reliability and hassle-free running. He will always give me a very safe tune (not that I've even got the PFC in yet).

So radiator, oil cooler, air deflectors/dams where possible, I plan on getting an Apexi power intake, simply because (apparently) they require NO maintenance and they don't use oil (so no risk of the AFM going bung like I've read happening) and I'm sick of cleaning/oiling my K&N panel and waiting for it to dry. I will add a cold air box and also a snorkel below it. I'll probably get a new fuel pump so I can be sure it's 100% capable for what I ask of it.

Edited October 17, 2007 by sl33py