RJ's STi - Page 75 - Perth-WRX.com

RJ999 · #**741** 28-04-2015, 08:52 PM

Quote:

Originally Posted by Serbaru

Found a chart of previous turbo BBK-L, with supporting mods.

Very nice...
I'm not too sure between 1.5 or 2.5 with an 8cm.
Dave's with 10cm was nice, power came in super hard but bit late in the rev range, probably not responsive enough for my liking with a 10cm hotside.

Rossco · #**742** 28-04-2015, 09:18 PM

Snipped from the other thread:

Why are you getting 625+'s?

Complete overkill for your application...... 625+'s are $700 worth of head studs......Great if you can run 35Psi of boost - a waste unless you are sleeving & close decking the cases (which you aren't).

The ARP 260-4701 head studs are what I have in mine ($280) - I run 1.7 bar daily & rev it to 8500 rpm - the heads have not lifted in 4 years.........

I also have the ARP case bolts 260-5401 ($550) - Which add crank case rigidity - a far better investment imho.

RJ999 · #**743** 28-04-2015, 09:30 PM

From other thread
Rossco - See Jacob's foz had arp2000s gasket went, apparently 625s were the go.

also chose the 625s as I was reading from the Manley specs and CP's that recommends using 625s as it rates these parts to a crank hp rating of ~550HP while using 625s which is a safe area for the whp 350-400 that I want to get to.

What I'm not sure about now is whether I should throw in 272 BC cams in there while the engine is out and stick to the IHI vf43 turbo, or should I not do cams but get a Blouch turbo... I wonder what's the max whp my IHI VF43 is good for?
I can do one or the other, not both.

Rossco · #**744** 28-04-2015, 09:44 PM

I have Manley H-beams in my motor - with ARP 2000 bolts. The rods are rated to 150hp per rod. X 4 =600hp total - the limit is the torsional strength of the rod material, not the cap bolts.....

Like I said before I spin my motor to 8500 rpm.

Again you are over-estimating the bore strength of your stock EJ257 cases - H-Tuff rods are for 40psi+ applications......

Serbaru · #**745** 28-04-2015, 09:47 PM

Quote:

Originally Posted by RJ999

Very nice...
I'm not too sure between 1.5 or 2.5 with an 8cm.
Dave's with 10cm was nice, power came in super hard but bit late in the rev range, probably not responsive enough for my liking with a 10cm hotside.

2.5xtr with 8cm housing should come in early on a built 257. Around the 3500-3800rpm mark with supporting mods plus E85 of course.

nick73 · #**746** 28-04-2015, 10:06 PM

Quote:

Originally Posted by astralex

Is the 1.5xtr twin scroll? Or do they do a single or twin scroll version? Looking for a new snail for my dust collector.

They do both.

Dominator 1.5XT-R Twin Scroll JDM Turbo (WRX 01-07/STi 01-15) - All Categories

Dominator 1.5XT-R Turbo (WRX 01-07/STi 01-15) - All Categories

RJ999 · #**747** 28-04-2015, 10:08 PM

Quote:

Originally Posted by Rossco

I have Manley H-beams in my motor - with ARP 2000 bolts. The rods are rated to 150hp per rod. X 4 =600hp total - the limit is the torsional strength of the rod material, not the cap bolts.....

Like I said before I spin my motor to 8500 rpm.

Again you are over-estimating the bore strength of your stock EJ257 cases - H-Tuff rods are for 40psi+ applications......

Yes you have a good point...I've just emailed querying what I save if I swap to the normal H beams...If its not much price difference then I'll stick to the H tuffs.

H tuff is a big mofo

Rossco · #**748** 28-04-2015, 10:17 PM

Quote:

Originally Posted by RJ999

Yes you have a good point...I've just emailed querying what I save if I swap to the normal H beams...If its not much price difference then I'll stick to the H tuffs.

H tuff is a big mofo

It's not about price - it's about how much the rods weigh!

Basically, you want a set of rods that are as light as possible, but are also capable of handling all the forces the engine can generate (rpm and horsepower).

RJ999 · #**749** 28-04-2015, 10:33 PM

Quote:

Originally Posted by Rossco

It's not about price - it's about how much the rods weigh!

Basically, you want a set of rods that are as light as possible, but are also capable of handling all the forces the engine can generate (rpm and horsepower).

Yeah that's true... I guess going from 535grams to 560 makes it need more power to get that cranks shaft moving.
I'll run it past Nic and go H beams if he says they're ok...600Bhp rating is ~480 whp... its a bucketload of whp which I'm not planning of getting anywhere close to.

dazdavies · #**750** 28-04-2015, 10:50 PM

You're not building formula one engines fellas. 25g is nothing, it won't be felt, it won't be even be quantifiable. I had Pauter X Beams in my last big power engine they weighed a hefty 593g each.
With a GT35R on it the car saw 1.8 bar at 3800 rpm and revved through the 8000rpm without issue. It was very responsive.

If you're worried about rotating mass then look at the savings to be had from lightweight flywheels and crank pulleys etc. Worrying about 25g per rod is absolutely pointless.

I recommended the H-Tuff for a reason he should stick with those.

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