rb30 turbo upgrade

[Z24O]

i have an rb30 with a T3 in my 240Z,it's a 5 speed,intercooled,15psi,standard turbo(plain bearing) 7th injector with a Wolf 3D computer.............i am a little dissappointed with the performance off the mark

it makes very little boost in first gear,possibly because ??the gearing(box and diff, already 3.36:1) is too low??the car is so light??

my question ,.....is it worth trying an auto box and a ball bearing turbo

if so is a higher stall converter of any use or should i be trying to load it up early with a very tight converter?

which turbo would you recommend for a quick spool up without completely loosing top end?

i am looking to use a standard nissan turbo off a factory import if possible,which ones are ball bearing and how do you tell from photos....you guessed it..ebay!!

thanks guys

paul

[stony]

3:36 are kinda tall. maybe its the tranny gearing ????

 

Anyway are you getting alot of tire spin in first gear?? If so maybe a stickier set of tires will help. are you drag racing it? If so auto will always be faster.

 

Just my 2 cents

[mario_82_ZXT]

Don't know the exact specs of the turbo, but isn't a T3 just a little small for an RB30?

 

Mario

[S15 200sx owner]

Go for something modern & ball bearing, the Garrett GT35R seems to be a good size for the RB30, it should spool real well and make lots more power than your old school T3.

 

I will be running RB30 with RB25DE head and have chosen the GT35R after much homework, and have gone with the larger 1.06ar on the exhaust housing, if you want faster spool and if you are SOHC still then go with the .82ar on exhaust side, cant go wrong!

 

http://www.horsepowerinabox.com in Aust have them pretty cheap these days, i got mine from James Thagard in the US (on this forum), worked out well.

[Z24O]

thanks for the reply guys

 

to answer some of the queries.....

 

i am not getting any wheelspin in first gear as the turbo doesn't seem loaded up enough to make boost,first gear is over pretty quick and you are reaching for second where some boost is made

 

the T3 came out standard on a car over here called the VL commodore which had a nissan rb30 sohc six in it,it made 150kw standared with about 5 psi,i reckon my car is making about 220kw at the moment

 

the garrett gt35 seems awfully big to make the low down torque/quick spool i am looking for,does sound good for top end hp though!!let me know if you have this turbo on a sohc 6

 

any input on spooling up the turbo with an auto vs a manual....and if so what stall converter should i be thinking of(high stall or "low" stall?)

 

thanks again

[S15 200sx owner]

The problem you are describing of not making as much boost in the lower gears is quite common. As there is not much load on the engine and its not making that much exhaust gases to spool the turbo up.

 

In my experience most turbo cars generate a higher boost level with every gear you go up! as the load becomes greater.

 

What you must remenber is that the GT35R is a Ball bearing turbo (which spool up much faster than a plain bearing as in your old T3.

 

I would still go for a GT35R (its a very common turbo for your application) but maybe go with the smallest ex housing of .64 (i think).

 

I would not go smaller than you have already have.

 

If your problem is as bad as you say, you should start looking at the system you are running to supply signal to your wastegate.

 

One thing that you can do is to attach a canister (like a empty aerisol can with a fitting screwed into the end where the spray button goes) "T" it into the signal line that goes from your manifold to the wastegate. This will in effect let the wastegate stayed closed that little bit longer while boost builds rapidly and essentially "overshoots" your normal wastegate pressure, before settling back down to normal presure after a split second or two (this lenght of time of Boost spike can be tuned by the size of the canister) Ie. Bigger = longer, Smaller = Shorter.

 

This little trick essentially fools the system into building boost faster and harder. Also quite useful on the Highway, when you punch the accelerater, gives you a short over boost spike, to get you up and going and then it automatically drops to normal level after a few seconds.

 

Simple but effective, Give it a go and see what happens.

[260DET]

A mate of mine has a RB30ET engine in his Z with the original but hi-flowed turbo. After a lot of research he is going to a GT35R for plenty of lower down and mid range punch. Not sure what a/r the turbine is, probably the .82, see here http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT35/GT3582R_714568_3.htm

 

If you want to go cheap then check out a VG30 single turbo. But apparently they are popular for two liter engines, may not be much better than the laggy TO3 for a three liter.

[Z24O]

thanks guys,appreciate the input,flaring the boost idea sounds appealing........real cheap and quick,lol

any ideas on the auto/manual dilemma??stall speed etc

cheers

paul

[S15 200sx owner]

A mate of mine has a RB30ET engine in his Z with the original but hi-flowed turbo. After a lot of research he is going to a GT35R for plenty of lower down and mid range punch. Not sure what a/r the turbine is' date=' probably the .82, see here [url']http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT35/GT3582R_714568_3.htm[/url]

 

If you want to go cheap then check out a VG30 single turbo. But apparently they are popular for two liter engines, may not be much better than the laggy TO3 for a three liter.

 

I wouldnt go with the VG30 single turbo, way too small, I run one of those on my Mini circuit racing car, it has a 1370cc engine, makes about 200hp and is not that laggy believe it or not!

 

sorry 260det, no offense eh.

[Pyro]

Bad turbo maybe??? A T3 should spool up quickly in this application.

[Z24O]

the turbo has just been rebuilt,it boosts well in other gears....particularly 3/4/5 when it spools up very quickly

i am leaning towards thinking that the issue is the gearing just too low in first,suppose i could always just take off in second OR try the auto(which i would prefer to drive anyway)

any thoughts on autos vs manuals for turbo (street)cars

any suggestions on converter stall speeds.....i am used to high stalling performance V8's with cams,don't know if this applies to turbod engines as well??????