Rb20det Minor Performance Upgrades (update Turbo Selection)

[sama1500]

That's why I plan on getting it tuned with the rb25 turbo I have on there at the moment, if it's fun at that stage of power I'll probably stick with it for quite a while before going for a turbo upgrade

[Kanaric]

I found in the US DSM and EVO take off 16G turbos for like $200 you can get a housing from kinugawa for them for like $250. Talking USD here but if you bought a RB25 already you might as well just rebuild that. You probably could get EVO 3 and lower or VR4 16G turbos in Australia for a good price I would bet.

[Matvei27]

2530 @ 1.1kpa *1000

Z32 AFM

some sort of performance exhaust system (duh)

ARC 105mm SMIC

101.5 RON fuel (about the same as ultra-premium in JP)

= 220kw at wheels with stock injectors @ 99% duty cycle (which is not good, but you get the point).

Replace the injectors and you might pick up another 5~10kw, but you literally NEED to replace the injectors since you don't want to run at 99%.

This is the exact setup me and my friend are using. If you don't have access to fuel above 98 RON, you need a front mount pronto.

And Poncams do make a slight difference in torque. The gears make a difference in response. Here is a video proving such:

See the graph at the end. The torque increase = due to cams, the turbo coming on earlier is due to him having also used adjustable gears. Both together = good improvement. Worth $700? Up to you. I used the Tomei Poncams and Tomei adjustable gears.

For example, if I changed to a RB25 and 2535 or GT-RS, and changed nothing else in the setup, I would make the exact same power level but it would be earlier. The advantage to the RB25 though is if I switched to a front mount it would have a lot more potential. No matter what, the RB20 is going to max out at around 400bhp, whereas the RB25 is capable of 400~500.

That's what I found with my car, ymmv.

Edited March 25, 2015 by Matvei27

[Roy]

So what cam gears did you have before the Tomei cams went in?

[sama1500]

i already have a front mount and run 98, does running the cams and cam gears together make the turbo come on sooner or is it just the cam gears? i dont plan on getting cams but if cam gears themselves can help response a little that would be good as they're relatively cheap

[Matvei27]

So what cam gears did you have before the Tomei cams went in?

I bought Tomei Poncams and Tomei cam gears at the same time. Before that was 100% stock. If you run the Poncams without the adjustable gears you will not be able to adjust your tune for more low down power, which is what you want on the RB20DET. Definitely don't get them without the gears. The notion that "they're maximized by Tomei at the factory to run without gears" blah blah blah is bullshit, yes they are designed so you can use them without gears if need-be, but even Tomei admits that using them with gears is better on their rather lengthy technical discussion on the Japanese site. Because it lets you have more control over your results, whereas using them without gears gives you absolutely no control over where they make that power. On a RB20DET you want to adjust the gears for down-low, on a RB25DET you would probably want to adjust them for up high since the RB25DET sacrifices some of the top end.

i already have a front mount and run 98, does running the cams and cam gears together make the turbo come on sooner or is it just the cam gears? i dont plan on getting cams but if cam gears themselves can help response a little that would be good as they're relatively cheap

Here's how it will work:

1. Cam gears alone > improved response (turbo spool earlier)

2. Cams alone > improved torque, especially in the midrange, but doesn't help low-end at all and doesn't increase turbo response.

3. Cams + gears > improved torque + improved response

If you just want to improve response get the gears, but I think the Poncams are worth it for the huge midrange torque improvement they provide. See the graph at the end of the video above.

I wouldn't just get Poncams without the gears, however, since you'll damage your low end response. If you use both together you can get an improvement across the rev range without sacrificing much of anything (except your wallet).

The cams are around $500 US, the gears are $200 US. Aside from getting a better turbo, it is the best $700 you can spend on a RB20DET because for most people it will fix the things they hate about it. It's not an extra 500cc, but it's something.

Just don't get anything bigger than the poncams on a RB20DET, it will suck. The procams are really meant for the RB22 and especially the RB24DET, but Tomei doesn't offer the kits to make those anymore. On the RB25DET, I would still say you should use poncams unless you are doing the Tomei RB28DET kit, in which case use the procams.

That's something I am considering for when the RB20 blows, but mine only has 66,000km on it so that won't be for awhile.

Edited March 27, 2015 by Matvei27

[Roy]

Tah...my trials showed std cams with cam gears gave me better power everywhere vs cams, inc torque. Playing with the tune/timing etc with cams just got me back to the same place.

But i run a very diffrrent turbo setup and the cams were with both a plazmaman plenum and before the plenum so engines would be working very differently.

My mate swore the drop in cams helped his HKS 2530 setup as well so....many ways to skin a cat

[Matvei27]

Tah...my trials showed std cams with cam gears gave me better power everywhere vs cams, inc torque. Playing with the tune/timing etc with cams just got me back to the same place.

But i run a very diffrrent turbo setup and the cams were with both a plazmaman plenum and before the plenum so engines would be working very differently.

My mate swore the drop in cams helped his HKS 2530 setup as well so....many ways to skin a cat

Did you use the Poncams or the Procams? The Procams won't help at all. If you were using them you were using the wrong cams.

Edited March 28, 2015 by Matvei27

[sama1500]

Well I guess that's cam gears added to the list, depending on how much they improve response I may be able to go for one of the hypergear turbos

[yoshiii335]

Hello Roy,

I was told by some of the members here that the forward facing plenum is not really useful for the RB 20Det. What kind of set up are you using yours for and for street or track?

[Missileman]

Everything is a compromise, cam gears are cheap and if you're not sure of their quality you can supply new fasteners of known strength, what's your budget for this gtst?

[sama1500]

i dont really have a set budget although the less i spend the better, in terms of engine work i dont plan on doing anymore after the current things im doing to it, so injectors, afm, nistune, possibly cam gears and turbo

[Missileman]

so its not a resto or a track car but your daily?

[sama1500]

yes its my daily, i do plan on taking it to the track occasionally though

[Roy]

Did you use the Poncams or the Procams? The Procams won't help at all. If you were using them you were using the wrong cams.

Ok,Full Trust TD06-20G setup with std inlet plenum and cams optimised with cam gears all tuned up. I then tried Apexi 260/8.8mm cams and went backwards. Tried different cam gear settings and engine lost response and didnt made the same peak power , never actually catching the std cams. Engine sounded tough but was seemingly over cammed.

So std cams went back in.

After everyone saying how good 6boost manifolds are I sold my Trust manifold and gate and went Turbosmart gate and 6boost

So that was a disaster...spend money to lose power. At this point i tried 256/8.5m Poncams and did stuff all to help response but did make a bit more power. At this point I was desperate for response so in went std cams again which made the thing a little plunchier

So reading about Plazmaman plenums...I thought I would give one of them a try....hopefully grab some improved response

LOL...nope. So going to 6boost and Plazman was a step back ON MY SETUP. Perhaps because my tune and setup was pretty well optimised and proven with a few years of track work before I started trying different things.

For me, if I had stuck with std inlet plenum and Trust manifold and gate my car would have been a good bit quicker than with the bling bolted on.

I lost a headgasket when a hose under the inlet went in traffic so I put in an NA R32 RB25DE that had rebuilt internals. All the bits from my RB20 were swapped over and after a bit of trialling my TD06-20G with an 8cm and 12cm housing and with / without the Poncams put back in...the Poncams in my RB25DE certainly helped the power curve , though didnt really change when it came on

Ev

Even then we found a problem with the Turbosmart gate so its possible it was leaking on the std cam pull making the setup a bit lazier. With the gate fixed it held boost and made way better top end, around what the RB20 was making. The above plot wasnt full tunes. I just wanted to see the general behavior of the setup of different turbo, housings, cams etc to decide which direction i wanted to take. Ended up going T67 and frankly 12 months later I am going back to my custom billet turbo

SO, after 16 years of playing with my car, 15 of it with an internally std RB20.....from a value perspective the std inlet and cams give the IMO the BEST bang for buck

If you want to run Poncams then there are those that have had good results...but inc tuning, labour and cams its what...at least a $1500 mod and I guess thats up to the individual to say whether that investment is worth the improvement (keeping in mind that some people go backwards)

[sama1500]

over 270kw out of an rb20

[Roy]

Feed the things E85

E85, std inlet manifold, a better turbo ...something like a FP HTA 71 or HTA 68 turbo and it would be pretty easy to blow my results away....lol the sh1t you learn getting it wrong

[GTSBoy]

over 270kw out of an rb20

Feed the things E85

E85, std inlet manifold, a better turbo ...something like a FP HTA 71 or HTA 68 turbo and it would be pretty easy to blow my results away....lol the sh1t you learn getting it wrong

Yeah, not to belittle Roy's result, but ~270rwkW was not an uncommmon power level for TD06s on std manifold in Japan back at the turn of the century. The JMS car (here in Aust) was in that territory even before I bought my RB20 car, and that was last century. You'd expect things to have only gotten better with better specced turbos, management, ignition, etc etc.

[Roy]

LOl, the problem with RB20s are just like the JMS car they put the wrong turbo on things and when the result is a compromise they blame the RB20. LOL putting a gate on the std manifold, using a 20G off a rotary with a waay too big A/R turbine housing will certainly make good power and turn tyres...but it was alwaas going to be a compromise. Must be RB20s

But that drift Onevia was just a bit of fun....and they knew it was less than optimal

There is nothing special about my setup at all. Those that have done similar / copied have all got the same or better! Just dont put a turbo built for another engine on an RB20 or run a MINES ECU etc etc.

[sama1500]

fair enough, while looking at some different turbos i came across this http://www.ebay.com.au/itm/Kinugawa-Turbocharger-Bolt-On-3-Anti-Surge-RB20DET-RB25DET-TD06H-60-1-T3-8cm-/271795646032?pt=LH_DefaultDomain_15&hash=item3f48486e50 would something like this have good response? much cheaper than garrett or hypergear options which would cover the cost for some cam gears