Crank Strength And Upgrading Options.

[Spoolup]

I have received the 2 x 95mm stroke cranks. I am going to build a new bottom end for my engine using one of them. I will use the exact same supporting parts ( head, turbo, cams, exhaust etc etc ) as on my current RB30/25. This way I can do a back to back comparison between the two engines ( apples to apples ) and overlay the two dyno charts. By doing this there will be something to compare the stroker crank setup to, as opposed to just building a completely new engine and having no base as a comparison.

I am just waiting on the new rods to go with the cranks and I can start the build.

Ill post up some pics of the cranks soon.

Edited September 22, 2009 by Spoolup

[Gerg_R31]

I have received the 2 x 95mm stroke cranks. I am going to build a new bottom end for my engine using one of them. I will use the exact same supporting parts ( head, turbo, cams, exhaust etc etc ) as on my current RB30/25. This way I can do a back to back comparison between the two engines ( apples to apples ) and overlay the two dyno charts. By doing this there will be something to compare the stroker crank setup to, as opposed to just building a completely new engine and having no base as a comparison.

I am just waiting on the new rods to go with the cranks and I can start the build.

Ill post up some pics of the cranks soon.

are the cranks balanced? or knife edged like the other stroker cranks?

[Spoolup]

Balanced but not knife edged.

[Travis Trayhern]

sounds very intresting, hope it goes smooth the build up and has some nice improvments throughout the power range.

what sort of price is this kit?

I have received the 2 x 95mm stroke cranks. I am going to build a new bottom end for my engine using one of them. I will use the exact same supporting parts ( head, turbo, cams, exhaust etc etc ) as on my current RB30/25. This way I can do a back to back comparison between the two engines ( apples to apples ) and overlay the two dyno charts. By doing this there will be something to compare the stroker crank setup to, as opposed to just building a completely new engine and having no base as a comparison.

I am just waiting on the new rods to go with the cranks and I can start the build.

Ill post up some pics of the cranks soon.

[Gerg_R31]

anything new?

[Gerg_R31]

I've been playing around with an engine dyno/ calculator simulator and its calculated roughly a before and after figures of horse power torque etc with the stroker crank

(as long as i have had all of the motors figures including flow figures at each measured level, i have gotten very similar to what has been acheived on a real dyno -/+ 1-3hp)

all 4 have exactly the same specs as you will see, though what is not shown is both have a 64cc in combustion chamber, 10cc piston dome, 4cc valve releif in piston and a flush deck height

this is not a garanteed before and after power results with the stroker crank but a simulation/ comparasion of what results may be expected with only change in stroke, results will vary depending on supporting internal and external componants

Non-Turbo

i have also added a turbo set up, everthing is still exactly the same, just with a turbo of which i chose from a drop down menu in the program. I am also aware that different turbos and supporting mods will change the end results

Turbo

[Rolls]

Be interesting to see what numbers that program gives for a 3L and then overlay the power/torque curves on the same graph, give a nice visual representation of where in the rev range the gains will be had.

[Spoolup]

I will be assembling the new stroker bottom end soon. The custom rods arrived today

This will be run on my exact same setup that I have used with the 3.0L bottom end. Same turbo, head, comp ratio, cams, exhaust, etc etc

So I will be able to overlay my previous setup compared with the stroker engine ( ie dyno power and torque curves )

So a straight up comparison will be available.

[Gerg_R31]

same specs as in previous post

dyno1 is the rb30de the dyno2 is the stroker rb34de

Non Turbo

Turbo

Edited November 11, 2009 by Gerg_R31

[Spoolup]

Wait for the real world stuff :-)

[nzeder]

Trial cranks due next week

So looks like these are not full counter weighted (assume the pic is of the 95mm stroker crank) I would have thought if you were going to the effort of building a custom crank it would be fully counter weighted?

Would the 95mm stroke generate more harmonics and having it full counter weighted might help reduce some of this? I am not an engine builder or engineer so just putting this out there for others more in the know to reply with more logical info.

Love the idea of a 3.4l hmm if my RB26DE powered 260z (shell still in bits) does not cut it looks like I might have to consider installing one of these stroker crank like this into a RB30 bottom end and slap on my 26 head for 3.4L of NA power

[Rolls]

So looks like these are not full counter weighted (assume the pic is of the 95mm stroker crank) I would have thought if you were going to the effort of building a custom crank it would be fully counter weighted

Yeah I was going to say how did you do all the calculations for the size and shape of the counter weights and balance it?

[Spoolup]

As these are the trial / prototype cranks we just copied the std crank. The std crank does a terrific job and sees 10000 rpm in serious drag engines. Why reinvent the wheel. Having said that - if I have any dramas with these cranks its an easy job to have the next version redrawn into full counter weight cranks.

I have had the cranks checked and balanced here in Oz - all good.

Yeah I was going to say how did you do all the calculations for the size and shape of the counter weights and balance it?

Edited November 12, 2009 by Spoolup

[axe s]

so is there an expected date of release??

im starting to get some blow-by in my 25... i don't think it will last to much longer... lol..

[Bond]

Any updates????

[Spoolup]

SPOOL Billet 4340 95mm crank

SPOOL 4340 I beam conrods

CP custom pistons

Edited December 24, 2009 by Spoolup

[NYTSKY]

Looks the goods!

What can these rev too?

[Spoolup]

no idea.. lol

Will find out soon

Revs are irrelevant anyway.

[N1GTR]

What makes you say revs are irrelevant?

Also, do you know the rod stroke ratio of this kit?

[shanef]

What makes you say revs are irrelevant?

Also, do you know the rod stroke ratio of this kit?

They are as relevant as a 7000rpm limit on the std crank.