R32 RB20DET questions

[S13 Silvia]

What is the stock turbo?

What is the max boost capacity of the stock turbo?

What is the stock boost level and where abouts is this measured?

What can the boost be up'd to using a manual bleed valve safely without detonating with stock cooler?

What can the boost be up'd to with a R33 GT-R cooler?

[Guest SadisticRage]

Answers to the last 4 questions.

1. Being ceramic wheeled it wont tolerate more than 16psi for long....I have seen one boost to 19psi

2. Stock boost tends to be in the region of 9-10psi measured from the black sensor box on the firewall which feeds back to the factory guage (or aftermarket guage where applicable)

3. This will depend greatly on fuel and atmospheric condition, 12psi is safe...beyond there some will tollerate it, others wont. It has to be remembered that the R32 is 10yrs old now so fuel pumps and injectors are often not 100% hence the varience.

4. With a stock turbo, perhaps 2psi above the 12psi max threshold mentioned above. It is worth considering though that the pressure drop across the GTR cooler often defeats the purpose and a smaller cooler may be more appropriate.

[Doctor]

1. The stock turbo is a T3 can't give you information on trims etc as I don't know.

2. The stock turbo can safely run below 14psi.

3. The stock boost level is taken from the plenum I beleive as I have a GTS4 i dont have a factory boost guage. If you are running high boost ALWAYS take the boost guage reading from the turbo outlet as the stock intercooler has a couple of psi pressure drop. So the engine could be seeing 14psi but the turbo would be putting out 18psi.

4. I would not go higher than 12psi with the stock cooler as your turbo would be boosting higher than 14psi and therfore the turbo will only last a little while before the exhaust wheel detaches itself. With 12psi you are on the edge of its efficiency range anyway, so anymore would hurt your power as the turbo starts producing alot more heat than usual and the stock cooler has trouble cooling it to an effective heat range.

5. AS there is only a small amount of pressure drop in the 33 cooler, you can safely run about 14psi no more though.

Make sure before you wind up the boost you get your mixtures checked and also your fuel pump tested.

Regards,

Doc

[Cubes]

I was still running rich with approx 14psi - 1bar of boost with the std fuel pump. The Fuel pressure bleed kit sorted it out.

Then I went and slapped on a new fuel pump (see sig) and it made it run really really rich up top to the point where the fuel pressure bleed kit had to bleed that much that the mid range leaned out.

I think it has somthing to do with the boost drop up top back to 12psi and the mid being 1 bar. Need a stronger wastegate spring, to stop the boost drop.

anway with 12psi she made 156rwkw with the af right but the mid range was gutless as it was too lean so i've richened it up a little but overall it does go better for the street.

Apparently if i can hold 14psi all the way through the rev range i should make around 170rwkw, so i've been told.

[S13 Silvia]

So the go seems to be 12psi on dead stock? Is this 12psi at the throttle or 12psi before the cooler?

Also, I'll have a R33 GTS-t fuel pump, will this be substantial for this level of boost on a R32 RB20DET and prevent it leaning out?

[Doctor]

7-9psi is dead stock. Approx 11psi with exhaust, pod ect.

My car car made just over 11psi at the plenum. Your fuel pump will be ok to handle this sought of pressure but will need to be upgeaded when you want to run a bigger turbo or 14+psi.

Doc

[Cubes]

Just as a guide i had a 3" exhaust std ic and 12psi of boost using a bleed and the fuel tuned using a fuel pressure reg bleed kit i made 152rwkw.

[adam 32]

joel

what dyno was that on??

so now with FMIC, fuel pump and more boost youre only making 12rwkw more??

does that dyno read high?! cos 200rwhp with exhaust, filter and 12psi seems a little high

[Cubes]

It was done on RPM's DD Dyno.

Same dyno as whatsisname's, freebaggins and that article in the zoom mag about FMIC's on the R33's. i.e the pressure drop across the std ic one.. Remember..

When stock it made 115rwkw.

on 12psi it had the fuel pressure reg bleed tuned so the fueling was perfect. and timing i think was set at 20degrees.

on 12psi with 25deg timing, fuel sorted out perfect af's and fmic i made 156rwkw.

Now with basically stock timing at 15psi it makes 164rwkw so with timing pumped in to it (maybe 25deg) which it won't be good to strap around in summer it probably would have made another 5-6rwkw.

Timing does make a good difference.

Also since then I have done the cam belt which was out one tooth in turn retarding the Cam Timing which would have made it a little more power up top but now it is heaps gutsier down low.

Also the compression is still perfect in my motor (~145+) and there is no oil at all anywhere breathing.

The head has been off before so i image the head has been shaved and maybe has a little more compression due to this.

The fmic didn't make it make much more power, fuel pump obviously doesn't make it make any more power but +3 psi more boost does bugger all as the turbo is past its effiency range and runs out of puff.

Tim did say that it should have made 170rwkw with the motor being in good nick etc.. but i also am running a stock airbox, no cai and stock air filter.

and not to forget stock ecu..

It does feel like it goes heaps harder now than when it was making 152rwkw.

[S13 Silvia]

Thanks for the advice. Actually starting to get into moding my engine now.

If I got a bigger turbo, maybe a t4 compressor on a t3 turbine, what boost could I run upto before the chance of stock internals braking?