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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

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

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.

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?

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."

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. :D

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.

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.

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