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

    • Nah that is not actually a lot. Just painting my GTR frontend and the little bits to make sideskirts/nismo flare pieces work correctly/fit on the sedan/mount up correctly came to about $7000. Is it a lot? Sure. None of this is economical. Economy would be shelling the car and buying a 2010 Corolla to commute in. The perspective of all of this is different.
    • I have the 2025 build re003s’ on my 06 XT Forester Turbo and I quite rate them for street wet and dry
    • I don't see any issues here. I've been saying all along this is a big job, the price reflects that.  When the car comes back perfect I'm sure it will feel like money well spent. 
    • Remember, take original quote. Double it. Then add a bit more. It's how any project goes.
    • So, I started this repair and got as far as "fixing" the holes with some fibreglass. God all those years working on boats came back quickly. I decided I'd reach out to some rust guys just to see what they would say about it. I came across a guy about 40 mins away and went to see him. He said the windscreen needs to come out, that there might be some more bits around the windscreen and he'd quote them at the time. But his quote was $300 to remove and replace windscreen and $3k for the damage he can see. He said he could respray the roof for $1200 and the bonnet for another $800 (somebody has previously rattle canned it, its horrendous). This is $5300 + any small additional bits. It's a lot, I get that and the name of one of my fave youtube channels 'Not Economically Viable' comes to mind.  I'm not being financially rational, but I've taken him up on the quote. He's opening a new shop in November with more room, so we're waiting for that. I'll leave the currently missing headliner out until then. I'm looking forward to it being fixed and having the paint looking nice again (lots of clear coat issues on the roof too). / flame suit on.
×
×
  • Create New...