To Stroke Or Not To Stroke

[xplosive32]

Hey guys i am currently working on an r32 gtst project i picked up cheap, engine is blown and engine bay is a mess so once i am done pulling the engine out and stripping/respraying the bay i am looking at completely rebuilding the rb20 block and head all machined, cracktested, balanced, blueprinted, forged internals, better oil pump bigger cams and so on. i know strokeing the engine is also an option but am not sure as to what other stuff will be required on the tuneing side of things. Has anyone had any experience with a stroked rb20 please let me know. Car also has rb25 box, button clutch, one piece tailshaft and nismo 2 way and also note will need to go into vic roads first with stock bolt ons as reg was cancelled by previous owner

[StealthX]

The beauty of RB engines is most of the parts are interchangable! IIRC you can use an 26 crank and 26/25 rods to displace about 2.4L...

Read about it here: http://www.skylinesaustralia.com/forums/Pr...tml&hl=Rb24

however it would be heaps easier to fit an RB25/26... Apart from purely being different, I don't know why you'd bother with the RB24...

Sounds like a cool project. Good luck dude.

[xplosive32]

That was definately a good read, i had originaly thought about the rb25 but it does seem that everyone has done it and it also involves me buying an rb25 with loom and then rebuilding it anyway, and yes before anyone tells me i do know how much easier it is to gain power from the 25 but i realy want to chase a safe and almost street legal 250rwkw from the rb20. The stroke kit i was thinking about was something like this http://www.lewisengines.com.au/prod158.htm

[StealthX]

That's pretty expensive for only 250cc more mate.

Keep in mind you could pick up a blown rb26 for less than 2k and use that crank and those rods with some custom pistons for 400cc more... Not to mention you could sell off the rest of the RB for some decent coin... Have a look in the forsale section, I've seen a few broken 26s for sale...

That stroker is a waste of money IMO, considering $5.5k = +250cc, or less than $2k can equal +400cc...

[edit] just saw that $5.5k is for a conplete engine package, my bad! That seems like a half decent engine package then! Personally I'd prefer more CCs if I was gonna go to all the extent of a stroker motor.

Edited July 3, 2010 by turbo x-trail

[TiTAN]

for the money just get one of their built RB25 engines, less money more capacity.

if everyone else is doing it there is a reason, just because its different doesnt mean its better.

[Roy]

If all you are after is 250rwkws then just throw in a std motor or do a simple rebuild with new bearings. There are plenty of people running around with 250-280rwkws in std RB20s with std plenums, cams, heads and bottom ends. They are strong motors.

I hear what people say about bigger RB transplants, but there is the engineering side of things to consider and registration/insurance side of things that mean its not so easy. Also, if you want all out performance i find it strange that so many people buy into the torque wins races etc. Sure its important and great on a street car as it makes the performance so lazy....but in a rwd platform it means you often spent lots of your time going sideways rather then forward. R32s are not that heavy so dont really need huge amounts of torque. Look at rotors, once on boost its jsut as much about hp then it is about torque down low. They are also geared pretty short std so forget all about what rpm the thing makes boost and power an dconsider at what road speed does the thing make power and boost. Small differentiation but makes a big difference to the performance of a car and something that so many people dont even consider. They see a dyno and they want the x scale in rpm? Why, its road speed that matters! Take this for example... Here is an example of what i was saying about not to forget wheel diameter and gearing. Here is the same RB20 (internally 100% std, cams head gasket etc)above vs two R34 Neo RB25s running GCG high Flow Turbos and Tomei cams.

I think there are a few options...

STD RB20 with a turbo and ECU upgrade

Compared to a std turbo RB26 with Poncams, and same dyno and same tuner

As you would expect the Rb26 spans the RB20 down low, but in the rev range that you use at the track the RB20 punches well above its weight!

If you really want to rebuild it then i think all you want to do is go oversized pistons, bump compression up to 9.0:1 and run a nice turbo and tune, even better if you can get E85 with the higher compression ratio. 2.1-2.2L with a bump in compression to help with the off boost drivability.

It is all relative, but i think its good to hear and read different experiences and examples. Torque is great at frying tyres, but if youa re going to put the bigger RB in the R32 GTSt you probably want the longer diff ratio and better supension to try and help with handling the torque hike.

[tridentt150v]

or you could just 'hang it all' and do an RB30..............

[Spurdo]

yes, Roy, road speed and traction has its merits. but i think when you own a rwd turbo nissan then the ability to go sideways was probably a sizeable factor in what influenced your choice of vehicle in the first place..

[bubba]

or you could just 'hang it all' and do an RB30..............

+11ty

yes, Roy, road speed and traction has its merits. but i think when you own a rwd turbo nissan then the ability to go sideways was probably a sizeable factor in what influenced your choice of vehicle in the first place..

+11ty

[Galois]

just a question regarding stroking (lol), that lengthens the stroke by shortening the effective radius of the crank (don't know the name of the shaft), so that would result in less torque right? so am i right in saying you're hoping the extra cc's will make up for that?

sorry to deviate

[GUN_METAL_GTR32]

dont stroke

drop in an rb25 with some simple mods and it will put out more than what u want for way cheaper.

if u wanna be really different chuck in an sr20det with a 3071r strapped to it.

now that would be fun lol

[Spurdo]

Galois..eh??

given that CC's = BORE x STROKE x NO. of CYLS, when you increase stroke alone, you are adding cc's, and adding stroke is the key way to generate more torque from an engine right across the board. as when the piston gets pushed down on combustion stroke, the point at which the connecting rod joins the crank gives the piston a certain amount of leverage to turn the crank, and the longer the stroke, the futher the connecting point is from the center of the crank shaft. more leverage on the crank = more torque at any given rpm basically.

im not sure what you mean by "effective radius of the crank". but put in laymens terms for you, "no"

[Galois]

god damn it, so stroking was explained to me as the shortening of the length of the rod connecting the crank to the piston rod, im guessing that is wrong then lol. thanks for the clear up

[Rowdyr32]

Go the 26. Roy knows that the 26 is the way to go but won't admit it. His 20 love is to strong!

So much easier to pedal a 26 vs 20.

I'd personally go a 25/30 with a xr6 turbo, gtr inj and remap. Could prob have it in and running $2k

[Bl4cK32]

snip/ rb torque hate

Wheres the love?

Every thread like this gets side railed by people confusing the search for better with a bigger motor. Sense means putting the best air pump in the car (25/26 lovers). Forget them though if you want to stick with the 2lt, then do so. Costs will be as expensive as you make it.

Ill probably throw a 2.4Lt together for fun at some point, because i want to see what a rev happy motor is like in the 32.

[Roy]

Yeh, if you have a decent enough budget, or the skills to do thins yourself then that is a big factor. But agree that strokers represent poor value compared to what other options. I will do one because I have been grabbing the parts when the pop up cheat (about 5 years). So now how have Tomei 2.4L pistons, solid lfters, cams, springs crank and rods all for less then 2k

But its all been said before. RB30s are for those that prefer roofies to romance. And RB25 into R32 transplants are for those that would sleep with their girlfriend's easy friend! ... i suppose i should add that if brains were dynamite most RB20 owners could not blow their noses

[xplosive32]

Thnx guys, feedback was great but i definately want to go with a built or stroked rb20 and i want everything that can be done internaly done purely for my own peice of mind (its like buying a new car, you know theirs nothing wrong with it and its 100% up to how you treat it that will determine how long it lasts) and then if i want to chase more power out of it in future it will be ready for it, no point in doing shit twice. As for the 2.4 ltr may be a little bit of over kill and i would be happy with just that 2.25 kit from lewis engines, i just want to know between the built 2.0ltr and the built 2.25 litre will their be much of a difference... and also when it come time to tune what would be the best way to tune the 2.25 ? can say an rb20 power fc be made to run it properly ?

Also my plans for the engine after the build and vic roads has passed it for reg are splitfire coil packs, some sort of better injectors (maybe sard 600cc or anything else someone can recomend for the mods) hybrid fmic, z32, bosch 040, rb25 highflowed (have OP6) and not sure what kind of wastegate yet because i only want about 15 pounds and undecided on tune or ecu and am open to recomendations. Any idea on roughly what kind of power that might pull at wheels ? on both the build 20 and how much more might i get with the 2.25 or will i only realy see a torque increase ?

Thnx again guys any more feedback would be great, also as i am new here just abit about me..

Names Leo, live in melbourne south east and love my motorbikes and big 8's (jap is all new to me and am keen to learn more), im not a mechanic i work as a sub contractor in a 6pallet refridgerated truck although i am pretty confident around an engine bay and do know more than the basic also do a lot of work in the garage on my own and mates cars like changing over engines, suspension diffs gearboxes and just anything that doesnt get too complicated although i love to give anything a shot just for the sake of learning, im 21 and pretty immature which reflect in my driving/riding although i am becomeing more tame with age. Thats all i think

[murrayis]

I say stroke it But then again What would I know

[Roy]

Lots of people ask about strokers and talk abotu RB20 build ups...but typically they are never seen to fruition. I am the worlds worst offender I think you will struggle to get definitive feedback on the improvements from a 2.2L. Expect that it may make the same difference of dropping an A/R housing, so guess about 200-300rpm improvement in lowering the power band!??!?!?!?!

[Bl4cK32]

can say an rb20 power fc be made to run it properly ?

yes. You use the loom / sensors as a guide as to what to use (since you will be using the std 20 gear)