R33 Rb30 Conversion

[JNR24]

A littel off topic:

1.st question:

Do "arias" make a set of NA pistons? for RB30. i went to www.rocketindustires.com.au and found them but they only say "tubro" and there is no RB30DE listing.

2nd Question:

What pistons do you guys recommend running? a set of NAs or the Turbo flattops??

NA:s 8.3:1

Turbos: 7.8:1

I currently going to be running a T04E on there but looking to run a GT3540.

What set do you guys think i should run?

Cheers,

Trev

[Sciby]

I guess it depends on how you want to drive... if you want a fairly linear power/torque line... then go the 8.3's... if you want top end power, go the 7.8's and wind up the boost.

Either way, it's all fun.

[DennisRB30]

RB30ET pistons will result in a CR lower than, 7.8:1

[Sydneykid]

Hi Dreg01, RB25DE heads are cheap and the early ones have no VVT, much simpler than RB25DET heads. I bought a complete RB25DE engine for $900 and sold the bottom end for $600, so the head cost $300. Plus I think the camshaft timing was a bit more aggressive than the RB25DET.

Hope that helps

[Cubes]

Sydneykid.. Just to make sure 100%.

The RB20DET oil pump can be used and will bolt up with no problems..

I picked up my head for $750. I as told it was off a R33 RB25DE and it has no VCT?!? I thought all the R33 RB25's had VCT?

[Dreg01]

Sydneykid, $300 for the head in the end is a good price.

sort of puts it back into perspective.

is $900 for an RB25DE average market value or is that cheap?

cheers

[Cubes]

1100 in SA

[Steve]

Dreg01 - think you may have trouble selling the stock bottom end for anywhere near $600, esp if you are stripping bits for the 3L. My opinion only, but sydneykid got lucky.

[Cubes]

Adelaide Jap were/are selling RB25DE heads for $750 as they couldn't get rid of the motor/head packages.

JNR24... Arias do make RB30E NA pistons.

They are $1600 inc. Rings from RPM Performance in Adelaide.

Apparently the Arias are one of the better forged pistons, CP's are apparently good also.

[Sciby]

What's the general opinion on Wiseco forged slugs?

[DennisRB30]

I would realy like to see that dyno chart referenced with RPM. I just need one of you to to look at the RPM when you are doing 100km/h in 4th gear (I assume raist has a manual with standard diff gears). If someone checks it out fo me I will modify the chart to include RPM and post it up.

Raist: What other mods have you done to get the 240 KW?

[R32 GTSTT]

how would 2 RB20 stock turbos run on a RB30? just asking coz im pretty sure the RB20 exhaust manifold bolts onto the RB25DE head, and i have a custom twin turbo RB20 exhaust manifold with two of these turbos.

[Cubes]

For the size of 2 RB20 turbos you will have to look at a bigger cc motor than the RB20 for decent response if you are looking at using the car for the street.

[DennisRB30]

I think they would be fine on a RB30DETT.

[DennisRB30]

Bump

"I would realy like to see that dyno chart referenced with RPM. I just need one of you to to look at the RPM when you are doing 100km/h in 4th gear (I assume raist has a manual with standard diff gears). If someone checks it out fo me I will modify the chart to include RPM and post it up."

[Cubes]

If the RB25DET makes peak power around 6500rpm I think I worked it out to being 38.15km/h every 1 rpm.

So at 95km/h * 38.15 = 3624rpm.

At 95km/h or 3624rpm it should be making 168rwkw.

At 149km/h or 5684rpm the RB30DET made its peak power of 252rwkw.

At 164km/h or 6256rpm the RB30DET made ~250rwkw and started to dropp power off quickly.

It sounds about right?!?

Raist were u using Adj. Cam gears?

Being it a RB25DET head which apparently has a less aggressive cam than the RB25DE NA head it should make power earlier in the RPM and slightly less?!

This is maybe why Sydneykid stated that when he did a conversion it made its peak power at 6200rpm there abouts. I think that was using an NA head, I could be wrong as so many figures etc have been posted and its easy to get muddled up.

[Sydneykid]

Hi Joel, isn't that 28 kilometres per hour per thousand RPM? Not 38 kph surely?

[raist60]

Its 38 mate. Also no adjustable cam gears.

[Cubes]

Originally posted by Sydneykid

Hi Joel, isn't that 28 kilometres per hour per thousand RPM?  Not 38 kph surely?

If I were to use 28kph the RB25 would be making peak power at around 4844rpm.

Where as 38.15kph equals 6599rpm.

I'm not really sure but it does seem roughly right.

It would be interesting to see exactly where the RB25DET does make its peak power as on paper it is 6600rpm.

[DennisRB30]

Here it is using 38 rpm per km. That would mean that a R33 GTSt does 3800rpm at 100km/h in 4th. That seems a bit high to me but it could be right. I know my R31 has taller gearing but it does around 3800rpm at 100km/h in THIRD. 4th comes in a 3000rpm at 100. That seems like a huge difference. It won't be hard for one you to check it out to make sure. Just look at the tacho when you are doing 100 in 4th gear.