Turbo Help!

[retox]

Hey all, I just took the 'stock' (or at least I think it is) turbo off my rb20... and when I compared it to the turbo that I have been told is from a Rb25, I noticed something strange.

The compressor wheel on the Rb25 turbo is bigger as expected... however, when I look at the exhaust wheels, the rb20 turbo appears to have a larger exhaust wheel... why would this be?

I would have expected the rb25 would have been bigger at the exhaust wheel as well due to having more gasses passing thru it due to being bolted onto a bigger engine.

I've included pics, can anyone shed some light on this?

Also, when I took the rb20 turbo off, some coolant came out of the dump pipe... again, should this be a concern?

Thanks in advance

RB20 turbo on RHS in this pic:

RB20 turbo on LHS in this pic:

Edited June 9, 2007 by retox

[retox]

anyone???

[leb]

That's weird.

I noticed that the compressor blades are completely different too. I thought they would just be bigger on the RB25's.

Perhaps the turbo on your RB20 has had a rebuild and the exhaust side of the turbo housing has been replaced?

I'm not turbo pro but it is the only thing that seems logical about it.

Have you been able to get your hands on another turbo from a RB20.

Keep us posted

[retox]

Was given this reply on another forum:

look att he angle if the fins on the rear turbine side of the turbo's.... the RB20 one has pretty big gaps allowing the exhaust gas to spin the blades easier being on a smaller motor... The RB25 has them closer together to restrict it a bit so it doesnt spool up early. From the pics tho the Rb20 exhaust wheel does appear bigger... Only one way to find out and measure them. Also the Rb20 rear looks newish and the 25 oldish if that makes sense could possibly have been a hi flow... U never know with a second hand turbo unless u measure it all up and know exactly what ur looking for lol.

Liam

does this sound right?... seriosuly lost now as to which would be better on the motor!!!

[Absent]

I've got my stock rb20 turbo here I'll post up a pic in the morning to see if theyre the same, when Im sober lol

[vinnie32GTS4]

im no expert but it sounds and looks like the rb20 turbo has been hi-flowed

[retox]

If it has been hi-flowed, wouldnt the compressor wheel be increased in size as well?... not sure.. still new to this turbo business

Either ways, hi-flow rb20 item vs stock rb25 item... which would be the better go-er on the RB20?

Also, as mentioned, I'm pretty sure some coolant came out past the exhaust wheel on the rb20 turbo when I was taking it off the motor... should I be concerned about that?

appreciate your input guys

[discopotato03]

Turn the turbos round sideways and compare the iron bearing housings , the later R32 RB20 turbos should be ball bearing and the middle is larger in diametre or fatter if you like . If your RB20 one is skinnier and its exhaust housing bolts are on a smaller pitch circle diametre then its probably an early R31 RB20 bush bearing turbo . These used much smaller compressors in an attempt to spool them early . From memory the exhaust housing A/R was very small and they're not much good for anything .

The Hitachi BB ceramic turbos have a small bolt head in the side of the bearing housing , general consensus is that its some sort of bearing pre load device but anyway only the BB Hitachi's had them - from what I've seen anyway .

Cheers A .

[retox]

The rb20 turbo is from a red top nics motor (aka R31 rb20)... and yes, the housing is more narrow when looked at side on

[discopotato03]

I think the other one looks like an R32 RB20DET turbo , real good upgrade to an R31 RB20DET .

Cheers A .

[MANWHORE]

I can't beleive no one's said it yet, but from the top pic, theyr'e both rb20 turbos. nissan motor 16v.

One of them may be the earlier bastardised vg30 with the nissan 16v comp cover, and non op6 rear housing. We'd need more pics of the back housing numbers, and the wheel up closer.

edit: oops, you guys beat me to it. haha

Edited June 10, 2007 by MANWHORE

[retox]

ok, got some better pics.

New Turbo (larger compressor wheel):

Markings on exhaust housing: 5173 near flange, 04U, 8. <--- on front (compressor side) of housing. Nothing on back

Old Turbo (Smaller compressor wheel):

Markings on exhaust housing: looks like 0074 (or A) near flange, 2, 8. <--- on front (compressor side) of housing. On rear (exhaust side of housing): B, 59S

Sorry about quality of pics - camera phone

Edited June 10, 2007 by retox

[retox]

pics up now