Jump to content
SAU Community

Recommended Posts

My mate's building up his RB26 N1 engine for streetable response and obviously as much power as possible. He already has GT2860R -5 turbos and Tomei 260 degree in and ex poncams. He's about to put a 2.7L JUN kit in it and the usual metal head gasket etc. etc. and just wondering what is required for the head to handle 10000rpm if required further down the track.

Obviously valve springs. What else?

Cheers

My mate's building up his RB26 N1 engine for streetable response and obviously as much power as possible. He already has GT2860R -5 turbos and Tomei 260 degree in and ex poncams. He's about to put a 2.7L JUN kit in it and the usual metal head gasket etc. etc. and just wondering what is required for the head to handle 10000rpm if required further down the track.

Obviously valve springs. What else?

Cheers

He wont EVER need 10,000rpm with those tiny turbos.

That's why i said "if required further down the track"

It's a brand new N1 long engine. Does it still need valve guides even though the ones in it are new?

How much further?

There is little point spending mega mega $$$ on a head if its never going to be used.

Even 400rwkw CIRCUIT cars don't even use more than 8500rpm.

If its built and tuned correctly, correct turbos for the power, then you shouldn't need 10k rpm for something thats mean to be 'streetable'

Basically the whole head needs to be re-kitted for 10k rpm. Stronger everything, upgraded everything.

Your mate really needs to decide this now rather than 'if required' as its mega $$$ and effort.

350-370awkw is a very good limit really for a streetable car (and can be done with the current turbos)

Can use the stock gear in the head which is reliable and so on.

And yeah - im trying to talk ya out of it cause i think its a waste of the cashola ;)

OK I'll re-word it. How many reliable RPM will a new RB26 N1 head with tomei 260 degree poncams and tomei type A valve springs handle? The stock rev limit is about 8000 I think so it's gotta be more than that. 9000?

Tomei type A valve springs are rated to 8500rpm hence this is your safe upper limit.

OK I'll re-word it. How many reliable RPM will a new RB26 N1 head with tomei 260 degree poncams and tomei type A valve springs handle? The stock rev limit is about 8000 I think so it's gotta be more than that. 9000?

if he wants it to live I'd advise sticking with 8,000rpm. stock limit is 7500 and to be honest with smallish low mounts and small cams there is no need to rev past that. for street use, sure blip it to 8,000 every now and then if you want some fun, but on the circuit, nothing will hurt your engine more than pulling big revs. look at all the reliable circuit GTRs, none of them run revs more than 8000 or 8500 tops. and many stick to around 7500. drag racing of course is another story.

brad, i was speaking directly to the Tomei engineer and the do not recommend reving past 8500 even with the full counter forged crank and rods! (maybe for drag only)

but for you top end (head) the n1 valves springs are uprated compared to standard, but you may need to uprate them again to ensure they close quick enough for those kind of revs and different retainers etc etc.

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

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...