Jump to content
SAU Community

Want more KW out of my RB20DET

HR31GT

By HR31GT,
in Engines & Forced Induction

 Share

Recommended Posts

HR31GT Contributor

HR31GT

Posted
Posted

I have HR31 Pasage gt serIII, with eccs rb20det, auto, 3", big fmic, 2.5" cooler piping,hks air pod, just recently installed a boost controller and upped it to .9bar, and its a bit laggy but it hits at 3000rpm. Looking to get more go(especcially more torque and bottom end_as funny as that sounds) out of it and thinking of either getting my ecu remapped, put an rb25det turbo, or fmac. And also as I live in brisbane it would be good to know any workshops that dynotune and have much experience with rb20's any help would be appreciated. Any ideas guys as i'm sure we all go through same stages........

Link to comment
https://www.sau.com.au/forums/topic/29275-want-more-kw-out-of-my-rb20det/
Share on other sites
Cubes Grand Master

Cubes

Posted
Posted

HR31GT,

So you have the older RB20DET. From memory it has a 248duration inlet cam which gives slightly more top end but causes the bottom end to be gutless. The R32 RB20DET has a 240duration inletcam and a 240duration exhaust cam, I guess this is why the new R32 RB20DET apparently has a little more poke down low and in the mid.

You could try fiddling with a set of R32 cams in it.

Some time ago a few people fiddled with R32 RB20DET NA cams. The only difference is that the inlet cam is a 232 duration which gives more bottom end and slightly more mid range. The car will be faster on the road even though it may pull a few kw's from the peak power figure.

If I were keeping my RB20DET I would slap a 232duration R32 RB20DE cam in to it and leave the exhaust cam the way it is or if I had the money to spend $400 or so on an exhaust cam I would go the 256 duration just to open up the top end a little more. Slap on a RB25DET turbo and pump 17psi in to it.

The only problem with the RB20DET's is lag when you want to make big power, some times even though you end up making more peak power the street speed will be slower.

HR31GT Contributor

HR31GT

Posted
  • Author
Posted

It does have eccs silver top rb20det in it,,,,,,,also i just been rising the boost and it seems to have a boost cut at around 0.8bar, is that normal....unless i unhook the factory bleed valve it wont go over 0.8bar, but if i unhook it starts to idle lower and it dont seem to be right.....any answers on that???

Cubes Grand Master

Cubes

Posted
Posted

nope its not normal to have a boost cut at .8bar unless you are running the non-silver top RB20DET ECU?!?!? Not sure on that one though.

My boost cut is up around 18psi.. It vary's with the day. On a warmish normal day it is around 18psi where as on a cold night if you wind out third or fourth depending how cold it is she will boost cut on 16psi. Damn scary when it does as you think you have broken some thing.

I've bumped my boost up to first 16psi and now i've gone to 17psi which pulls rather hard until around 5500rpm where boost starts to drop to 12.5psi.

I'm also running around 22degree's timing which makes a big difference to power delivery.

Unless your AFM is playing funny buggers causing the boost cut.

I'm not sure what it is with mine but every now and again it appears that boost rises and as it does the power delivery is not smooth. The power feels like it dips then picks up again. If I pull over and remove the AFM plug wiggle it around then plug it back in again all is normal?!?!

MM2death Grand Master

MM2death

Posted
Posted
My boost cut is up around 18psi.. It vary's with the day. On a warmish normal day it is around 18psi where as on a cold night if you wind out third or fourth depending how cold it is she will boost cut on 16psi. Damn scary when it does as you think you have broken some thing.

My 32 is exactly the same.

Scott

WazR32GTSt Grand Master

WazR32GTSt

Posted
Posted
HR31GT,

So you have the older RB20DET. From memory it has a 248duration inlet cam which gives slightly more top end but causes the bottom end to be gutless. The R32 RB20DET has a 240duration inletcam and a 240duration exhaust cam, I guess this is why the new R32 RB20DET apparently has a little more poke down low and in the mid.

You could try fiddling with a set of R32 cams in it.

Some time ago a few people fiddled with R32 RB20DET NA cams. The only difference is that the inlet cam is a 232 duration which gives more bottom end and slightly more mid range. The car will be faster on the road even though it may pull a few kw's from the peak power figure.

If I were keeping my RB20DET I would slap a 232duration R32 RB20DE cam in to it and leave the exhaust cam the way it is or if I had the money to spend $400 or so on an exhaust cam I would go the 256 duration just to open up the top end a little more. Slap on a RB25DET turbo and pump 17psi in to it.

The only problem with the RB20DET's is lag when you want to make big power, some times even though you end up making more peak power the street speed will be slower.

pumping 17psi into the rb25 turbo with its ceramic exhaust wheel is asking for trouble... they are only good at 14psi or below so keep that in mind

Cubes Grand Master

Cubes

Posted
Posted

What is the killer of the ceramic exhaust wheel?

Overspeed is no. 1 and then excessive heat/detonation.

When you increase the engine RPM the engine requires more airflow. As the engine RPM increases so does the turbo's shaft speed in order to keep up with airflow demand. An RB20 consumes less air than a RB25 so for a set boost pressure the turbo spins slower on the RB20 than it does the RB25. In turn this gives you a little more head room to run more boost and possibly match the air flow to make as much power as the turbo did on the RB25.

The other problem that blows the ceramic exhaust turbine is excessive heat. This is caused by running around a track flat out. I've heard of ceramic turbo's blowing with simply 12psi in this instance.

The japs have been doing it for some time now. 1.1-1.2bar on stock turbo's.

I initially had mine tuned at 15psi then I bumped it up to 16psi. For the last year i've been running 17psi. Although that 17psi is only up to 5500rpm where boost starts to drop down.

It also comes down to the turbo its self. Some times you get a good one some times you get a crappy one.

I've had the car for over 2 years now and racked up 60,000km's with the turbo pumping 1.1-1.2bar for a majority of the time.

When a car detonates it can also blow your turbo as its possible for a bit of spark plug to break off and smash in to the exhaust wheel. It all comes down to tuning and ensuring there is enough fuel around to keep things cool.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • sammi_d
      SAUNSW - Social - Aqua Golf @ Penrith - Sat 22nd March 2025

      By sammi_d · Posted

      Welcome to the new year, gang! We've ticked over into 2024, so as usual, we're starting the new year with a chill social out at Aqua Golf! So without any ado, here are the details: Date: Saturday 22nd March Location: Aqua Golf - Penrith Panthers Time: 4:00pm Map: http://tinyurl.com/saunsw-aquagolf All you need to do is bring yourselves down to Penrith Panthers to come and say "HI", hang out, and maybe hit a few golf balls at the drive range. Who knows where the night may take us... What we do know is that there are plenty of food options available at the Penrith Panthers complex. For those of us keen to hit a few golf balls, prices start from $7.00 a bucket. Aqua Golf is open til late, so we have plenty of time to have a few hits and laughs with each other! This is an official SAUNSW event and will be run under a Motorsport Australia permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU:NSW and thus, treat others accordingly. • Any misbehaviour will not be tolerated and you will be asked to leave. Thanks all! Looking forward to seeing you all there!
    • sammi_d
      SAUNSW Sunday Session - Self Raised - Sunday 9th March

      By sammi_d · Posted

      Kicking off our first Sunday Session for 2025, we'll be heading to the delectable Self Raised Snack Shoppe!! Get your tastebuds ready for a mouth-watering toastie and coffee! As always, this is the best place to meet up with the SAUNSW fam for a coffee, bite to eat, and a chat! So what are you waiting for? Block out the calendar, set your alarm in the morning, and come down to hang out with the SAUNSW fam! Date: Sunday 9th March Meet Location: Self Raised Snack Shoppe - Shop 4, 8/20 Sarsfield Cct, Bexley North NSW 2207 (carpark entry via Slade Road) Meet Time: Meet at 8:00am Map: https://tinyurl.com/saunsw-selfraised This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAUNSW event and will be run under a Motorsports Australia permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU:NSW and thus, treat others accordingly. • Any misbehaviour will not be tolerated and you will be asked to leave. Thanks guys and hope to see you there!
    • The Bogan
      NC MX5

      By The Bogan · Posted

      Pre-empting heat management  1. The Kraken manifold will be ceramic coated 2. Just purchased some peel and stick heat shielding stuff from car builders, I'll cover some of the firewall behind the dump and a little on the cam cover, this will be done prior to installation as I have ample room to get where I need to now before that realestate has more bits in the way, I'm also planning to modify the OEM heat shield to go back on, but that won't happen until after installation so I know where to hack it up, I'll also cover it with some some peel and stick to neaten it up after the hacking 3. As the dump is stainless with a flex joint coating isn't really a option, and wrapping isn't recommended for a stainless dump, so once it is installed I'll grab some shielding from car builders to cover the dump, as it has some stand off, it "shouldn't" cause any issues and it "should" just keep the radiant heat away from " melty engine bay stuff" Not for heat management, but I've grabbed some more black crinkle coat to paint all the shiny intake pipes, I'll pick the pipe work up prior to installation and use the paint booth and big oven at work to cure them, I'll then wrap them with some bubble wrap so they stay nice during installation
    • sammi_d
      SAUNSW - Cruise - Austi Beach Cafe - Sun 23rd Feb 2025

      By sammi_d · Posted

      We're back on, gang - Our yearly pilgrimage south to our favourite cafe for an awesome brekkie! Yes, that's right... we're heading down to Austi Beach Cafe for a breakfast run through the Royal National Park! Before you drool over your phones/keyboards, here are the details: Date: Sunday 23rd February Meet Location: Loftus Oval Carpark, Royal National Park, Sutherland Meet Time: Meet at 7:00am for a 7:30am departure Destination: Austi Beach Cafe, 104 Lawrence Hargrave Drive, Austinmer Map: http://tinyurl.com/saunsw-austicruise  RSVP: If you are planning to sit and have breakfast with us, please let us know, either by posting in the event, or by messaging us direct so we can confirm numbers with the venue. Itinerary: We will meet at Loftus Oval Carpark which has plenty of room and is low car friendly. This is a quick turn into the Royal National Park and some nice roads and scenery. After Stanwell Tops we will turn off and head onto the awesome Sea Cliff Bridge. Following this it is a short trip to Austi Beach Cafe. There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a Motorsport Australia permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU:NSW and thus, treat others accordingly. • Any misbehaviour will not be tolerated and you will be asked to leave. Thanks guys and hope to see you there!
    • imonpcp
      a31 chassis pinout/cluster wiring layout

      By imonpcp · Posted

      YO- have been searching and searching for an a31 chassis plug pinout, or someone who knows which wire is for tach.  ceffy was flooded past dash during a hurricane.  having an electrical gremlin appear. tach is wonky reading consistent with a short, and on occasion the right side of my speedo lighting will flicker just for a second then go back to normal.  if no pinout available does anyone know if the tach harness opens or branches anywhere behind the dash? im suspecting a possible root behind the radio as there are more shorts in that area on the accessory loop.
×
×
  • Create New...