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CP do make twincam specific pistons, pretty much everybody does nowadays.. on the spool website he lists DOHC RB30 pistons for 8.2:1 and 9:1 CR.

can do any CR you want just have to ask

can do any CR you want just have to ask

Or instead of being misled and guessing, you have to actually do maths as the piston DOES NOT have a compression ratio built into in

what makes a static compression ratio;

head chamber volume

head gasket volume/ average bore x thickness

bore size

stroke length

piston to deck height

piston dome/dish volume

In the tutorial thread there is a formular i wrote ages ago cbf posting link

Or instead of being misled and guessing, you have to actually do maths as the piston DOES NOT have a compression ratio built into in

what makes a static compression ratio;

head chamber volume

head gasket volume/ average bore x thickness

bore size

stroke length

piston to deck height

piston dome/dish volume

In the tutorial thread there is a formular i wrote ages ago cbf posting link

i know that mate yeh once you know all the above you can ask for a set dome or dish to get the CR you want

  • 2 weeks later...

a bit more of an update. Block has been machined and decked to remove oring. Walsh plugs along the sides of the 26 Head have been welded up. Head has also been shaved and preasure tested. Crank balanced with a spool collar fitted for the pump. Spool rods and cp flat top pistons have been purchesed from spool. Now all is getting sent off to be balanced and blue printed and assembled. Not taking short cuts this time. All bolts through out are now arp including L19 on rods and even the flywheel bolts. Pics loaded soon. Cant wait to hear it

Throw in a set of supertechs valves and double springs, (online or through fabre as they're the only supertech distributors in aus cheaper to get the master valve train package online) get seat pressure around 80-90lbs

In my opinion if this is not a dedicated track car, i wouldn't bother with the L19 studs, arp 2000 have a longer shelf life and will do the job just fine, but this is just my opinion

  • 1 month later...
  • 2 months later...

Another update on progress.....

Started all over with new block, crank, rods, pistons and cams, 100mm TB, custom single TB plenum, A new set of chrome rb26 covers, 6boost exhaust manifold has been ceremic coated. Block has been painted candy red over gold base. Cams are now 10.9mm lift 270 deg also got oversized vales and springs. Blue print and ballenced work is in the progress in brisbane. Will update further when motor is installed and tuned

  • 2 weeks later...

Another update on progress.....

Started all over with new block, crank, rods, pistons and cams, 100mm TB, custom single TB plenum, A new set of chrome rb26 covers, 6boost exhaust manifold has been ceremic coated. Block has been painted candy red over gold base. Cams are now 10.9mm lift 270 deg also got oversized vales and springs. Blue print and ballenced work is in the progress in brisbane. Will update further when motor is installed and tuned

nice.

will be good to see running.

so, plenty of vid!

  • 2 weeks later...

nice.

will be good to see running.

so, plenty of vid!

Yeh im a bit weird like that. I record all my dynos on a HD cammera. I found the people that im going to use to assemble it. Its going to cost 1200 plus what ever is needed to set shims and cams up. And 500-600 for run in and tune on the dyno. Block is going to the builder monday to get the walsh plugs fitted and then around to the painters and back to the builder. Then the head ache of rebuilding the gearbox after 2nd syncro has shit its self.

  • 4 weeks later...
  • 3 weeks later...
  • 3 weeks later...
  • 3 weeks later...

nice.

will be good to see running.

so, plenty of vid!

Some vids from the old motor and old tune

Not long now till the new motor will get tuned

Just gotta track down a rebuild kit for the gear box

^ This guys running a 30/26 and looks like he had the same or similar problem to you, in the comments section he wrote

"Haha cheers man, the car had a split weld on the cooler tank and could only make 16psi and on 20psi it had 323kw (432hp) atw so below 300 somewhere i would say. I just changed the computer to a platinum pro and put in id1000 injectors and it went from 415hp atw to 529 atw or around 380kw all on bp ultimate"

massive improvement!

Edited by discoPumpkin
  • 10 months later...

Motor is finally finished. Everything was blue printed and balanced by crankshaft engineering in brisbane. Was assemble by me at a performance shop with some advice on ring gap etc from them. 2 new cams 1 bigger then the other but there alot bogger then the hks 272 I was using. Thought I had a clearance problem between piston and valves but I dont. Was only the pads in the chamber leaving marks in the playdow. Have got a new gearbox and a new twin plate from direct clutches in brisbane. Just need a haltech and 1500cc injectors now. Havnt worked out the CR yet but will do soon. Slow build has taken over 2yrs but no short cuts taken. Hopping for better results then last time. AWD coversion not getting done as I got quoted 25g and I can buy a gtr roller and drop this motor in for less then that. Will post the results when its running

Look bud first thing is how stupid you just made your self sound. Your car originally came from os. And I really dont think the japs would be buying his stroked motor if they were no good like you make out. Especially with the technology they have. So in other words if the japs are youhit and only buy shit why do you drive a jap car... lol

2nd thing. Yes my car was a show car before I owned it making 450hp. I use it as a day to day driver and used a spool race prep head and made 550hp with the 6:1 comp. Now the new spool motor is over 1000hp and used day to day. Aint no show car.

3rd thing if your gtrs are half as good and fast as you make out. Why not bring it up to the winter nats here at qld and put it beside spools street trim gtr and sort it out on the track. Of course you will say you would win so there for there aint no reason why you shouldn't unless your scared and cant back the shit you dribble

First, like your first two posts in the thread, that most no sense, so um yeah right

Second, unless I forget how to read when I enter this thread you lost power putting the Spool head on, 450 to 440 is a lose if my math is correct, or is it 420-490 some where tuner/dyno dependant, so this new motor has made 1000hp or that just what your hoping for cause please correct me if I'm wrong but a motor that hasn't started makes 0hp, so who is dribbling shit know

Thirdly, I'm not into drag racing, I prefer circuit but you tell someone you run 1.07around Wakefield you get a vacant look but you tell em you run 11.1@123mph they get am idea, and given i live 10 minutes from the drag strip if I get home early from work on wednesday and feel like going fast I shot down to the drag strip for some fun, so driving to QLD to drag race is not happening, I did drive the VIC last year for Winton on Friday and DECA on Saturday, we have something like what you said you have in QLD here yeah so next time you come down for that shot me a PM and I'll come out for that and I'll race your 1000hp maybe car :)

  • Like 1
  • 2 months later...

First, like your first two posts in the thread, that most no sense, so um yeah right

Second, unless I forget how to read when I enter this thread you lost power putting the Spool head on, 450 to 440 is a lose if my math is correct, or is it 420-490 some where tuner/dyno dependant, so this new motor has made 1000hp or that just what your hoping for cause please correct me if I'm wrong but a motor that hasn't started makes 0hp, so who is dribbling shit know

Thirdly, I'm not into drag racing, I prefer circuit but you tell someone you run 1.07around Wakefield you get a vacant look but you tell em you run 11.1@123mph they get am idea, and given i live 10 minutes from the drag strip if I get home early from work on wednesday and feel like going fast I shot down to the drag strip for some fun, so driving to QLD to drag race is not happening, I did drive the VIC last year for Winton on Friday and DECA on Saturday, we have something like what you said you have in QLD here yeah so next time you come down for that shot me a PM and I'll come out for that and I'll race your 1000hp maybe car :)

You certainly know how to stop a thread Mick,haha

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