GTR Forum banner
1 - 20 of 29 Posts

·
Registered
Joined
·
116 Posts
Discussion Starter · #1 ·
I just blew up my 2.8L HKS Step 2 (bent the crank).

Thinking about going to an N1 block, bored to 87mm.

Stock keyed and balanced 33 crank

some forged pistons and rods.

I'm wondering what is the highest I'll be able to spin this setup?

I've got twin AX53B60-P21's I'll be using.

I was thinking 264 or 270 cams with pretty high lift. Procams???

Let me hear your suggestions keeping in mind that I already have those turbos but need to buy pretty much everything else...
 

·
Registered
Joined
·
8,804 Posts
I've spun mine to 9000, with reciprocating masses (rods and pistons) all balanced to within 0.5 grams of each other. I wouldn't go higher than that however, and I think my head didn't like running that high, it sounds a little different now and is slightly noisier.

So I'd personally say run it at 8500rpm, and do some serious headwork, put in expensive valveguides and make sure your valvetrain in general are bulletproof - step 3 valvesprings, etc.
 

·
Registered
Joined
·
393 Posts
Its the harmonics in the crank that kill the bearings. So you need to keep the revs to 8300 with std damper and 8600 with fluid damper or ATI damper.

Robbie
 

·
Registered
Joined
·
1,883 Posts
No need to run higher revs, past the point where the engine doesnt make any more power.

I run mine to 7600 max. Power is still on the way up at that rpm, but just to be save ive sett the 3-stage limiter to start at 7500rpm.

People always like to brag about how much engine revs, that is just plain stupid.

Asim
 

·
Registered
Joined
·
116 Posts
Discussion Starter · #5 ·
bragging about any ONE thing about your engine is stupid. it's about the overal configuration and specs.

planning on a fluiddampr

thanks for the responses guys. 8500 should be fine for me.
 

·
Registered
Joined
·
1,969 Posts
No need to run higher revs, past the point where the engine doesnt make any more power.

I run mine to 7600 max. Power is still on the way up at that rpm, but just to be save ive sett the 3-stage limiter to start at 7500rpm.

People always like to brag about how much engine revs, that is just plain stupid.

Asim
Asim, these are straight six engines. The only good thing about a low torque, short stroke, straight six engine is it's ability to rev. If you can't rev it past 7500rpm, what is the point in sticking with a straight six?

I don't get people who buy a turbo charged, low cubic capacity, straight six and want 'more torque low down'. That is just stupid. :mad:
 

·
Registered
Joined
·
1,883 Posts
Asim, these are straight six engines. The only good thing about a low torque, short stroke, straight six engine is it's ability to rev. If you can't rev it past 7500rpm, what is the point in sticking with a straight six?

I don't get people who buy a turbo charged, low cubic capacity, straight six and want 'more torque low down'. That is just stupid. :mad:
Please read my post again. :)


No need to run higher revs, past the point where the engine doesnt make any more power.
By this i mean, if the power drops off at 7800rpm, why on earth would you go past that? And stress out the engine?

Asim
 

·
Registered
Joined
·
1,969 Posts
Please read my post again. :)




By this i mean, if the power drops off at 7800rpm, why on earth would you go past that? And stress out the engine?

Asim
Sorry Dude, I read your post wrong, and mistook you for one of those fools that want a 'Race Bred' Skyline, but want it to drive like a V6 Turbo Diesel. :chairshot

My apologies. I should have gone to specsavers......................... although being from Sweden you probably don't get that comment :p
 

·
Registered
Joined
·
649 Posts
Going with the Fluidampr

Changing the Timing belt at the end of the month, got an N1 water pump, some Tomei Type B pon cams, Tomei belt, tensioner and Idler pullies, and a Fluidampr that just arrived today. Bought a new torque wrench off of flea bay that torques up to 600ft lbs, enough to handle that monster torque value for crank bolt. Scored the Fluidampr from Summit Racing, cost $480.00 shipped, Do Luck wants Y120,000 for the same thing, go figure. Got a Carbonetic Carbon Twin plate with Carbon Coated flywheel and pressure plate on the way, Type R Discs, and will be getting a new tranny to boot. Can't wait to put all this stuff on:)
 

·
Registered
Joined
·
1,883 Posts
Sorry Dude, I read your post wrong, and mistook you for one of those fools that want a 'Race Bred' Skyline, but want it to drive like a V6 Turbo Diesel. :chairshot

My apologies. I should have gone to specsavers......................... although being from Sweden you probably don't get that comment :p
No worries mate.
Firstly, im from Norway :chairshot
And we do have specsavers here... and i hate their ads on tv... :blahblah:

:D
Asim
 

·
Registered
Joined
·
116 Posts
Discussion Starter · #13 ·
powershift into 2nd and the whole thing just started shaking. tearing the motor down to see what happened. I've got the stock crank damper on there but I was running R34 N1 turbo's for christs sake. Not even "medium" power by my standards. Crank was REALLY old though so there is a slllllllllight chance of metal fatigue, for all I know the crank was 15 years old and had seen a hard life.
 

·
Registered
Joined
·
6,560 Posts
20+ year old cranks are just fine usually.
Our world record holding RB30 engine has a 23 year old, 200,000+ mile stock crank in it and we turn it to up to 10,000rpm at times.

Rob
 

·
Registered
Joined
·
116 Posts
Discussion Starter · #16 ·
20+ year old cranks are just fine usually.
Our world record holding RB30 engine has a 23 year old, 200,000+ mile stock crank in it and we turn it to up to 10,000rpm at times.

Rob
And how many years was that crank seeing +750HP?

I'm not talking about just time. I'm talking about high HP time. Saying that you can pull a crank out of a minus 400HP setup that has 100000000000000 miles on it and then be able to put 800HP on it doesn't really say jack or shit about the longevity of the crank life at high power.

I DO agree with what you're saying about cranks usually being fine, and I'd still be surprised to find out that the primary factor was metal fatigue in the crank. Probably a bearing. But for sure you've got to see what I'm saying about lifespan @ low power vs. lifespan @ high power and how the quote above doesn't really say anything.

My friend had a 750HP stock RB26 crank that saw 10+ launches a night, 3 nights a week for 8 years and never broke. THAT says something.

BTW, you're RIPS stuff kicks ass. My friend Doug here has a lot of your goodies on his purple 33 and the quality of your stuff is amazing, not to mention the bling bling.
 

·
Registered
Joined
·
6,560 Posts
And how many years was that crank seeing +750HP?
We have many engines around that power or higher that are 6-7 years old (have run 10s right from the start) and no problems with cranks.

I'm not talking about just time. I'm talking about high HP time. Saying that you can pull a crank out of a minus 400HP setup that has 100000000000000 miles on it and then be able to put 800HP on it doesn't really say jack or shit about the longevity of the crank life at high power.

My friend had a 750HP stock RB26 crank that saw 10+ launches a night, 3 nights a week for 8 years and never broke. THAT says something.
Fair enough, my point was that an old stock crank CAN handle alot of power and for a long time, we've run 1000-1400hp/ at up to 10,000rpm for nearly 2 years with what started off as a 23 year old 200,000 mile crank and its still fine, thats saying something too I'd say, to me it says billet or aftermarket cranks are not required.

Basicly I'm pretty sure people will find failers they may have won't be a result of the crank itself, it will almost certainly be a problem elsewhere.


BTW, you're RIPS stuff kicks ass. My friend Doug here has a lot of your goodies on his purple 33 and the quality of your stuff is amazing, not to mention the bling bling.
Cheers.
 

·
Registered
Joined
·
2,056 Posts
By this i mean, if the power drops off at 7800rpm, why on earth would you go past that? And stress out the engine?
Hi,

Not sure whether you mean peak power is (in this example) at 7800rpm or whether you mean that power noticeably tails off at this point.

For max acceleration through the gears, optimum rpm to shift up is above peak power rpm. Think of the area under the graph. If you shift up *at* peak power, you're going to be nowhere near it in the next gear. The ideal point to shift up is the rpm point when the power in the next gear will be the same as the one you're currently in. That keeps the max area under the graph through the gears.

Of course, that point might be above your rev limiter, or above the rpm that you're comfortable to rev the engine to. But you did question why you'd want to rev above the point the power dropped off.

If your peak power is at, say, 6500rpm and the engine seems to hit a wall at 7800rpm then I agree with you ... depending exactly what you meant by "power drops off".

Cheers,
Kingsley.
 

·
Registered
Joined
·
116 Posts
Discussion Starter · #19 ·
We have many engines around that power or higher that are 6-7 years old (have run 10s right from the start) and no problems with cranks.



Fair enough, my point was that an old stock crank CAN handle alot of power and for a long time, we've run 1000-1400hp/ at up to 10,000rpm for nearly 2 years with what started off as a 23 year old 200,000 mile crank and its still fine, thats saying something too I'd say, to me it says billet or aftermarket cranks are not required.

Basicly I'm pretty sure people will find failers they may have won't be a result of the crank itself, it will almost certainly be a problem elsewhere.




Cheers.
I'd say you're totally right. I think my problem was the damper. Looking at other harmonically failed engines, they all snapped crank in the SAME spot. :bawling:
 

·
Registered
Joined
·
6,560 Posts
I'd say you're totally right. I think my problem was the damper. Looking at other harmonically failed engines, they all snapped crank in the SAME spot. :bawling:
Where did they snap? any pix?
 
1 - 20 of 29 Posts
Top