Vg30's On Rb20det

[lows_13]

I've read a heap of posts regarding VG30's on the RB20det motors,

and it seems everyone that has/or had one on the car wasn't happy

with its performance.

Are they as bad as everyone says?

[Cubes]

Don't use.

The VG30DET BB Turbo is nothing more than a RB20DET turbo with larger turbine and compressor covers.

The compressor wheel is exactly the same as the rb20det item. Your much better off with a RB25 turbo, that at least is a compressor upgrade.

[lows_13]

Shorly it must put out more power than the standard RB20 turbo though

[discopotato03]

Could try the RB25 exhaust housing on the RB20 ceramic BB turbo , it works with the RB25 turbo /2.5 engine and VG30 exhaust housing . All thats changing is the turbine housing ARR . Reducing turbine inlet (back pressure) is a good way to increase power and the RB20's turbine housing is TINY .

Its a real easy job provided you can find that housing and everything fits up exactly the same .

Well worth a go , cheers A .

[Cubes]

Shorly it must put out more power than the standard RB20 turbo though

<{POST_SNAPBACK}>

There's much more to power than just peak power.

The VG30DET turbo has much less 'average' power. It will accelerate slower on the street. It also feels like it makes next to no boost in first gear, click second then it makes some decent boost.

My assumption was the turbine housing was simply too big for the compressor match on a 2ltr. On the RB30DET its great, spools really quick and feels as if it has quite a bit more mid range and top end.

I've had a VG30DET turbo on a rb20det and on the street it was not fun, power delivery came on very very smooth at around 4k, by 5.5-6k it started to get up and go, then I was changing at 7-7.5k.

I put the rb20det turbo back on pushed 1bar through it and it was much quicker on the street than the vg30det turbo. I had the rb20det turbo holding boost to redline, it didn't feel sluggy up top and pulled all the way to just over 7000rpm where I would change gear. Without it holding boost it felt as if she was begging me to change up at around 6500rpm.

I've been in a rb25det turbo equiped rb20det, it was a perfect match.

Slightly larger turbine to help it rev to 7.5k easier + the added bonus of a larger compressor wheel to deliver more airflow.

Don't mess with the VG30DET turbo for an extra $100 or so you can pick up a rb25det turbo from the forums here.

I picked my vg30det up for $350 from sau, I've seen rb25det turbo's going for $400 on sau. I didn't want a rb25det turbo as the turbine housing is too small for the 3ltr.

I wanted as large as possible to extend the higher rpm peak power.

Its worked quite well on the 3ltr.

[lows_13]

Would certain mods help the VG30 spool up quicker?

I'm going to look a one today that has a VG30 on the RB20det,

it has a few mods like GTR Frount Mount, Turbosmart E-Boost, full 3 inch exhaust (dump pipe), GTR fuel pump.

[r33_racer]

I wouldnt think those mods would help resolve the problem. Because its got the larger ass you need to increase exhaust flow to effectively decrease the lag associated with it. You would probably need camshafts and/or a inlet&exhaust adj cam gears to help that problem if you were going to go ahead with it. Maybe even just a exhaust wheel, retard timing and let more gas pass through.

The only thing there that would even come close to helping is prob the dump to free up the flow so theres no backpressure.

[lows_13]

I just took the car for a spin now and it didn't seem heaps laggy, boost started at about 3000rpm but didn't really pick up until around 4500 - 5000rpm, this was on 14psi

[Cubes]

Lag is subjective, a car that doesn't really get moving until 4500rpm I would consider laggy. Mine had good boost at around 4k and pulled well but didn't really start to pull nice and hard (rush) until 5.5k.

If the car is in good nick I wouldn't not buy it because of the vg30 turbo, I would still definitely buy the car, sell the turbo and buy a r33 rb25det turbo.

Have the ecu tuned and be happy with 190rwkw.