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I've just changed my induction kit to the Apexi version. In doing so, I noticed that there was some oil in and around the afms. Having consulted on this, popular consensus is that she's breathing heavily as I'm running nigh on 1.3 bar without a catch tank (next on shopping list). She isn't using oil, plugs clean as a whistle and she doesn't burn oil at all so I'm relaxed that this diagnosis is correct.

However, I'm told that in both the latest HKS and Apexi catalogues, both companies recommend that you do not rev the RB26 higher than 7.2k, 7.5k max with the stock crank or you'll end up doing the crank and more, plus you'll add to this breathing problem especially if you're running at higher boost. I've got my rev limit set at 7.8k at the moment which, if this advice is correct is too high.

Any thoughts on this....?

Peter.
 

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Hi Peter,

Just one concern, why would the factory limiter be set so high if you cannot safely rev beyond 7500 ? as far as I can tell the rev limiter is about 8250 rpm...

I dont usually change up a gear until I am pulling about 7800:eek: (when driving in a spirited fashion) so if this is true I could have done the botom end without even thinking about it.

Also there are cars out there that rev higher than the factory setting with an aftermarket top end but std crank etc... ?

confused..

/Steve
 

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Hi Peter,

I'll prob get flamed to death for saying this but here goes.

I currently have the limiter set to 8500rpm on my PowerFC, the same as it was on my previous Mines VX-Rom ECU. I don't think you will do much damage if you go up and above the reccomended rpm limits on the odd occasion like when drag racing, but i wouldn't recommend it all the time or when on track sessions for prolonged periods.
My engine has done over 50k now and it get taken the the limit quite a lot when dragging or on test days. Doesn't seem to be any major oil burning going on. I get the feeling that the tuners in Japan are a bit over paraniod about stressing stock engines. I believe that the us tuners have run a stock engine at over 700bhp for a prolonged time with no problems, I myself am running over 500bhp at 1.35bar from time to time with completely stock engine internals and head gasket.
At the end of the day I wouldn't think Nissan would have set a factory standard rev limiter at over 8k if it was a high risk of the engine failing.
Just my own opinion though.

Mike
 

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Discussion Starter #4
Steve,

In the 2 1/2 years since owning my car, I've not heard this before so it came as a bit of surprise to hear about this today. As you know, I don't hold back myself and all has been OK so far, but everything is OK 'til it breaks I suppose...!

Mike,

Do you have a catch tank fitted? Does anybody know who stocks any combination washer fluid/catch tanks? I've tried four likely places this morning without any luck....

Peter.
 

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You could try the dreaded Demon Tweeks.

or alternatively go for the old beer can method !!

I think that Mike has hit it on the head there, with the tuners just being a bit over cautious. It really wouldn't do to have the rev range reduced that far. A honda Vtec engine goes higher than that !

/Steve
 

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Limiter!

Mike,

I remember our chat about this issue at Donny mate i think it was just before we watched the "fast & Furious" on Gaz's laptop in the "mobile cinema";)
I was actually suprised at your set limiter as well, as you know i have a different setup on the bottom end with the steel crank etc and only rev it to 8350 legally under the advisement of Mr Bell..

But after a long chat with Rod about this topic i think that some of the rpm limit is down to the cams you are running as well and how they are timed up on a tuned car...

Will see you soon mate..:D

Peter,

I had an itnitial problem with oil surge on my car as on the Big Suingle's the turbo does not seal to 100% and therefore if you run more than 1.4 bar boost you get surge past the seal and therefore need a catch tank to vent the excess, after this was fitted everything was hunky Dory!

BTW I am on the "old" HKS Green filter setup so will be interested in any info you have on your new filters...

Cheers

Stu
 

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Peter,
Kiki at Option always tells me never too exceed 7.2k. But my engine is relativly stock.
When he was running 650bhp with a HKS 2.8 kit, he never exceeded 7.2k either! Maybe he was running it in, I don't know.
What I'd advise though is to give him a bell.
He will be able to help you.;)
 

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Peter,

I don't currently have a catch tank either, I was thinking of making my own at some point as well as I want to be running at 1.4bar and above soon.

Mike
 

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I've heard this one also. Kiki got the information from a contact at HKS Japan who said that on a stock crank that hasn't been balanced you shouldn't exceed around 7.2K. A cynic would suggest that this is HKS' method of increasing sales for their crank damper kit (or whatever it's called).

Talat.
 

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Discussion Starter #10
Scott said:
Peter,
Kiki at Option always tells me never too exceed 7.2k. But my engine is relativly stock.
When he was running 650bhp with a HKS 2.8 kit, he never exceeded 7.2k either! Maybe he was running it in, I don't know.
What I'd advise though is to give him a bell.
He will be able to help you.;)
Hi Scott,

It was Kiki who told me when I bought the Apexi induction kit so....

I can't find anybody who stocks the catchtank so perhaps an opportunity for a little inventiveness and, as Steve suggests, a call to Demon Tweeks.... Trouble is most of their stuff has quite small inlets so not sure if it'll work OK.

Mike,

Do you know whether you breathing heavily? Trouble is, you won't know necessarily unless you whip a pipe or filter off.

Talat,

You old cynic you! :)

Peter.
 

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Hi MikeR33.

I was always told that you had to change the standard head
gasket if going above 1.0 bar.

How are you running 1.35 with the standard one?

Did I just waste my pennies on an HKS one for bugger all.

Cheers Tom
:smokin:
 

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Discussion Starter #12
Tom,

I was told by those in the know that 1.3 is OK on the stock gasket....

Peter.
 

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oil

well my limit is set at 7650 revs that is what Rod said to rev my car to
that is because the big end bearings in a RB26 are not all that wide.it is the bearings that are the weak point in the engine.
i got Rod to lighten and balance my crank,rods,HKS pistons,flywheel and clutch it also got the HKS big end bolts fitted.
to run a RB26 over 1.2 bar boost you should fit a head gasket
and to run 1.4 bar plus you should then think about fitting pistons as well the std ones wont last long.
i dont need to rev my car hard :p
max power is at 7100 revs,torque is at 5060 revs:p


KEITH
 

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1.2 BAR

i was told 1.2 bar
the reason for that is running at 1.2 bar plus gives you a higher
comp ratio and with that it will give you DET and you dont want that. with the POWER FC i think you can map out the DET
but that would be the wrong way to go
would be better to do the head gasket then map in plenty advance to make the most out of your engine.

correct me if i am wrong


keith
 

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Sounds good re the Pistons

Looks like I'm going over 1.4 then ;) .

It is interesting this thread and would be nice to have a follow up from the tuners over here.

I suppose this is where the Dyno Days come into their own. If your engine is tailing off dramatically at say 7,800rpm then theirs no point revving it past that drop off point, is their ?

glen
 

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Peter,

At my last service when I had the PowerFC and injectors done Mark said it was breathing a little but not enough to worry about and less than he expected for the mileage and the boost level.
When I had the inlet pipes off there was a film of oil in there, but not a massive amount.

Hi Tom,

I was warned that it may cause failure at that boost level, but i'm not getting much det shown on the PowerFC (max reading of 38 on the det scale when at 1.35bar @ 8400rpm). I suspect that the head gasket will go sooner or later (prob sooner) but i'll just have to hope it lasts a bit longer. I only run this boost level for performance tests, not everyday. Normally 1 bar for everyday, 1.2bar to show off a bit.
I was going to have just the head gasket replaced but I want more power as well so I fancy new pistons/rods etc, just need some more time to sort the finances out and don't see any point in having it dismantled 2 times.

Cheers,
Mike
 

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no point

as you said glen if the power on a dyno run is dropping off
why rev it to 8000 revs ?
at star jim takes the revs to just over the drop off point
my max power is at 7100 revs
jim stopped the dyno run at 7160 revs.
it is the torque that pushes your car along the road not bhp
so no need to rev the nuts off your car.:smokin:

KEITH
 

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HEAD GASKET

MIKE I WAS TOLD THAT IF YOU BLOW A HEAD GASKET ON A SKYLINE THERE IS A GOOD CHANCE THAT THE CYLINDER HEAD WILL BE SCRAP.

THAT CAME FROM SOMEONE THAT HAS WORKED ON SKYLINES FOR A VERY VERY LONG TIME

KEITH
 

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Hi Keith,

Agree on the torque being what it's all about, but for 1/4 mile/race type of stuff you will get a lot faster time if you can hold you gears for another 1000rpm, even if you drop 50-100hp from your peak power as the gear ratios multiply/divide the power to the road according to the overall final drive.
Also I don't get peak power until 8300rpm anyway with the standard cams in.

Mike.
 

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Hi Keith,

I was probably going to get a new head anyway when I go for a rebuild as i've heard that they can be cracking with the sort of mileage i've done.
It only needs to last another few months now so i'm just hoping I can get throught the last few major stressing performance test days of the year :)

Mike
 
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