High Compression Rb30de?

[impreziv]

im currently working on my project R32 GTR, but when i get bored of that project i really want to do an all motor RB30DE in an S13 coupe, or an R32 GTS.

ive read through a bunch of the RB30 threads here and on other forums. i have a few unanswered questions... what compression ratio would you get adding an RB25 head onto the RB30? and from there, whats the easiest way to get a higher compression ratio?

is there a piston set i can buy that will give me a higher compression? i think it would be really cool to do an 10:1 or 11:1, but i dont know how high people have gone. if anyone has any URLs they could throw my way, id appriciate it much.

[BADR33]

well there is a thread down the page a bit titled "my rb30de" thats my rb30de build. im running high compression. and from the distance i have done its a very drivable car with plenty of power from take off all the way up to redline. well i havnt reved up there quite yet. but thats another 800ks away... lol

the compression ratio is 8.3 if you just put rb25 head on stock rb30e block.

the cheepest and easyest way to get high compressoin is to use rb25de pistons and you will end up with a compression ratio of about 10.4.

mine is 10.43:1 using rb25 vvt head and rb25de pistons

if you wana raise it even more then you could deck the block and plain the head.

[Dahtone Racing]

i remember peter from advan giving me alot of info on this engine a while back when i was going to build one

they built one with 12:1 compression and raced it in endurance type stuff

give em a call they should be able to help you out

[Warpspeed]

If you use the standard flat top pistons in the RB30 you end up with around 8.5:1 compression.

But you can fit the RB25DE pistons to your RB30 bottom end. these pistons are domed and will give you a compression in the range you want. I am not sure of the exact figure, but it will definitely be greater than 10:1

[impreziv]

thanks for the replys guys, that was the info i was looking for.

do people generally use the RB25DE ECU for this kind of project? there is a local guy here that can tune those kinds of ECUs, would this be sufficiant?

Edited March 11, 2006 by impreziv

[Warpspeed]

Your best bet with an ECU is to not stuff about, go straight to a power FC.

The results you get will be highly dependant on proper engine tuning, and a stock ECU (whatever type) is going to be a definite handicap.

[BADR33]

im running a rb25de ecu for my run in.. seems to be running fine at the mo.

its mainly just till i decide what mods i wana do and what ecu i want to run.

im considering link at the mo as it would be suitable if i decide to go with hex throttles.

but then i need to find a tuner i trust that isnt an 8hr drive away...

[impreziv]

ok, i didnt know there was a PFC for the RB25DE

so how much power could one expect from a 10.5-11:1 RB30DE?

[BADR33]

um im getting mine dynoed in 1 week so i can give you a firmish figure then.

i would be expecting atleast 135rwkw. if its less it probly means my tune is way out.

all i can say is so far i have impressed a few of my trubo mates with the power and torque of the NA

i think you just use a powerfc for rb25det?

[Warpspeed]

Just did a quick computer simulation on Dyno 2000.

RB30, 11:1 compression, extractors, std cams = 200 Hp at 5,500 Rpm

Estimated 126 RWKw, an absolute torque monster 210 Ft/lb

RB30, 11:1 compression, extractors, 262 cams = 266 Hp at 6,500 Rpm

Estimated 168 RWKw, 231 Ft/lb at 5,000 Rpm, but it looses a lot of torque below 4,000 Rpm.

That would be my guess if it is properly tuned.

[ColdFusion]

  Warpspeed said:

Just did a quick computer simulation on Dyno 2000.

RB30, 11:1 compression, extractors, std cams = 200 Hp at 5,500 Rpm

Estimated 126 RWKw, an absolute torque monster 210 Ft/lb

RB30, 11:1 compression, extractors, 262 cams = 266 Hp at 6,500 Rpm

Estimated 168 RWKw, 231 Ft/lb at 5,000 Rpm, but it looses a lot of torque below 4,000 Rpm.

That would be my guess if it is properly tuned.

What's 210Ft/lb in Nm?

[Warpspeed]

Dyno 2000 is American, so they still use the imperial Hp and Ft/Lb.

210 Ft/Lb = 285 Nm

[BADR33]

http://img234.imageshack.us/my.php?image=dynosheetsml7kv.jpg

i got that dyno sheet off the rb30det thread in forced induction.

the red line is it as an NA, the black is trubo so obviously its running the lower comperssoin but it still put out 135rwkw.

my car pulls hard right up too rev limiter. i cant rember what that is tho as i have only hit it once by accident cus the car just revs so damn quick for a stock flywheel.

so that dyno thing isnt that accurate but thats cus its a simulation

i guess next sat i will have an answer of how much power and torque.

it has impressed everybody who has ridden in it so far and im definatly happy .

[Cubes]

That dyno run wasn't exactly N/A.

The wastegate was simply wired open.

When I had my rb30det run in it made 133rwkw with the wastegate wired open on a different dyno, so a very similiar result.

It made stuff all boost until peak power due to the wastegate being wired open.

So... 133rwkw on 6psi with crap all ign. timing and from memory 10.5:1 afr's.

Just because its a 3ltr doesn't mean it will make more power than the 2.5ltr. But do expect more average power, which is what impresses people when the ride in it.

With a slightly higher comp ratio and good tuning it will make the same peak power as an rb25de with the same mods.

All the best, I'm keen to see how it turns out.

[342Four]

im really interested in badr33's dyno run

it would be cool to run in a car like that - by all acounts it seems to be quite the torque monster - and that linearly all the way up to redline