Dreaded Fist writes about Nissans and about modifying cars for high performance.
The Torqueless Wonder
Nissan's legendary Skyline GTR captured the imagination of millions of fans, appearing in countless movies and video games. The GTS-T, GTS25-T, and even GTS-4 Skylines are more than capable performers on both the street and track.
This article focuses on the often-misunderstood, underestimated RB20DET, as found in various late-eighties/early-nineties Nissan's. Featuring an incredibly short stroke (under 70mm), the RB20 is an engine that was designed to rev. In fact, expecting any worthwhile acceleration below 4000RPM in the turbocharged RB20DET variant would leave one wondering where the power was.
Despite lacking displacement, checking in at a scant two liters, the RB20DET has developed quite a following, thanks to its robust build quality, rev-happy nature, and relative simplicity. The best part about the RB20DET engine is that if you push yours a little bit too hard, you may find yourself needing a new engine. No big deal really; replacements cost next to nothing on the used market. Expect to pay a small fortune should you buy new from Nissan, however).
Due to the RB20DET's small-bore, short-stroke design, the engine lacks sufficient torque below 4500 rpm. This "gutless" feeling can be fixed with some careful R&D around camshafts and turbocharger sizing. At the very least, a set of mild camshafts installed on a stock-turbo-equipped engine can really bring the engine to life with a proper ECU tune.
This article will focus only on turbocharger upgrades for the RB20DET engine. See my other article for information on RB20 camshaft upgrades.
There are many turbo upgrade routes one can take with an RB20DET engine. The easiest and cheapest is often upsizing to a larger OEM Nissan turbocharger. The RB25DET turbocharger is a quick and easy bolt-on upgrade to the RB20, is slightly larger, and can provide a bit more boost and power. Read on to find out more.
The stock RB20DET turbocharger is a tiny, T3 framed baby. Due to its ceramic turbine wheel and small size, the stock turbocharger begins producing useable boost very low in the RPM range on a stock RB20DET engine.
But because of its ceramic turbine wheel, the stock turbocharger is notorious for failing at higher boost levels. Most agree that 12 psi of boost is the maximum reliable output. In some motorsport cases, the stock turbo has been reliably stretched to 14.7 psi of boost, to produce a claimed 268hp on a stock-internal engine. The key to reliability at these higher boost levels was a rich ECU tune, which kept exhaust temperatures to a minimum. Heat breaks down the glue that holds the turbine to the shaft. Cooler temperatures mean more reliable operation.
RB25DET OEM Turbo
The stock turbocharger available on the newer RB25DET engine is larger than the stock RB20 turbocharger and thus can provide more power in a very cheap upgrade. The downside to the RB25 turbocharger is that it too has a ceramic turbine wheel, which will fail if the exhaust temperature is too high. Maximum recommended boost is 14 psi with a safe tune. For the best results, transfer the wastegate actuator from your RB20 turbo onto your RB25 turbo, as it has a higher base-boost pressure than the RB25 actuator.
The video below demonstrates what an RB20 equipped with an RB25 turbocharger is capable of doing on a racetrack. The car has a very wide powerband and seems to have a nice punch of torque in the midrange.
HKS Sport Turbo Upgrades
HKS has a line of "sport turbo" upgrades, which feature precisely sized turbochargers designed for that specific application. HKS offers a 2530kai turbocharger upgrade, which with the right supporting modifications, can produce as much as 350-360 horsepower. These results can be achieved with aftermarket camshafts and extensive ECU tuning. The 2530 is a smaller turbocharger which provides a healthy powerband, with excellent response on the RB20 engine.
HKS also offers various other turbocharger upgrades, such as the 2835 turbocharger, which can support up to 380 horsepower, making it slightly less responsive than the 2530 turbine. A newer GT-RS turbocharger upgrade is available, which is said to support up to 400hp in a very responsive design. Also offered are the much larger GT3037 and GT3037S turbochargers, which can support low to mid 400 horsepower outputs. As these turbos are much larger than stock, a significant decrease in response and a much higher boost threshold should be expected.
Garrett produces a large variety of turbochargers for various general applications. As the turbochargers are not designed exclusively for one particular engine configuration, choosing the appropriate Garrett turbocharger is crucial to achieve the best possible performance. In addition to this, Garrett turbochargers do not come in complete "bolt on" kits, and thus require piecing together the various parts required to bolt a turbocharger up to your engine.
Many will argue that since Garrett produces HKS turbochargers, it is silly to pay the huge premiums for HKS turbochargers. But if you want a straight bolt-on upgrade, the HKS series turbochargers are the way to go, because they come with everything necessary to bolt the turbocharger onto your engine. Garrett turbochargers require shopping around for everything. If simplicity and perfect fit is what you desire, HKS is the way to go; if you like the idea of an adventure, save some initial cash and pick up a Garrett turbocharger.
"Trust" Turbo Kits
Trust (Greddy) produces various bolt on and full upgrade turbo kits for the RB20DET series of engines. Various power outputs, from slightly more than stock to a ton more than stock, are available. The most widely regarded Trust turbo kit available for the RB20DET engine is the TD06-20G full turbo upgrade. This kit includes a new manifold, wastegate, turbocharger, gaskets, lines and everything else needed for a complete bolt-on upgrade.
The video below features an R32 Skyline GTS-T equipped with a Trust TD06 20G turbo kit and demonstrates how responsive the turbocharger is, and how fast the car is with the kit equipped. Notice how fast the car transitions from negative to positive manifold pressure. Careful throttle control is needed to reduce wheel spin induced from the high power output.
In closing, the RB20DET engine, while lacking displacement and featuring a huge torque hole below 4000rpm, is a great bang-for-the-buck engine. Replacements are cheap, and due to their robust bottom-end construction, they love to be abused. While RB series engines aren't exactly known for having great oil systems, the RB20 is an engine that can spend all day bashing the rev limiter, only to come back tomorrow begging for more. Look after your RB20, and it will look after you.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Alex on October 14, 2019:
Very helpful ! I think opting for an r32 gtst is better than a gtr because it's less expensive and the rb20det is pretty solid and I'm also not looking to have more than 300~350whp. But nowadays cant seem to find these turbo kits anywhere... all i can find is the cxracing turbo kit. Guess I'll have to search for tubing, intake, exhaust manifold intercooler. Any suggestions, and also where to buy them ? Thanks in advance !
Elias Borrero on September 29, 2018:
Where can I even find the Trust TD06 20G turbo kit?
shukry on December 29, 2012:
Hi there. I just upgrade to rb25 turbo but my car will start jerking 4000 rpm . Any idea to overcome this problem. Thank you.
Arif Ramli on August 13, 2012:
hello.. when i change to rb25 oem turbo and increase the boost to 13psi the engine hesitates to rev for a while during boost.. is this normal? any solution for this problem?
Ben on May 08, 2012:
Gt30 turbos seem to be common but what is their spool time?
Dportis24 on April 30, 2012:
Wow you know your aftermarket. I wish I had aftermarket parts in my Jetta
ahmed on April 18, 2012:
thank you for the article
i am new with the rb engines, and i have just bought rb20de and my question is what is the differences between the rb20 de and rb20 det?is there any differences in the pistons or the camshaft? and what i need to upgrade it to rb20 det. i will appreciate your respond
Saiful on March 21, 2012:
To share a bit after reading at other side, T04e turbo variant such as T3/T4 is not suitable if u want to find power before 4k rpm due to rb20 displacement (exhaust gas) and amount of air sucked to the turbine....It seems that if u already fit this one, expect power come off at higher rpm range.... i might be wrong
ali on February 21, 2012:
how bout actuator??take out or leave to normal funtion??can i stop the actuator funtion after i install external gate?
Dreaded Fist (author) on February 07, 2012:
I'd try a set of adjustable cam gears and try tuning those on the dyno to see if you can wake the car up any earlier. If you can afford to experiment, I'd try the td06 as well. td06 turbos seem to do really well on rb20's. Are you spinning the engine to 9000 rpm with stock camshafts?
Dreaded Fist (author) on February 07, 2012:
RB25 turbos are great upgrades for rb20 engines. Bolt on and they make great power. With the RB25 turbo at 14psi, you could probably crack the 300bhp mark without much trouble. You don't need an external wastegate at that power level, but if you want it, you can get it welded to the OEM exhaust manifold, and then have the wastegate on the rb25 turbo welded shut. That way you could run the 25 turbo with the external gate.
Dreaded Fist (author) on February 07, 2012:
I've always been a fan of adding lightness. If you want free mods, you can start removing all the stuff that isn't really necessary. I've removed nearly 250 pounds from my car and the difference in performance is massive. If you're looking for engine performance and don't want a gutted street car, I'd recommend some type of ecu tune to make the most of your current modifications. There's lots of power to be unlocked with a good tune, for sure.
Holland on February 06, 2012:
i have a freshly rebuilt rb20det, (Race bearings ect) custom front facing plenum, 90mm throttle body, 440cc injectors, spitfire coils, top mount turbo setup, T3T4 Turbo. Link ecu also tuned to 20psi @ 9000rpm ;) anyway what i have to ask is the t3t4 doesn't come on boost until roughly 3500 rpm, full boost at about 5250, would aftermarket cams fix some of the chronic boost lag im having? i realize it will mean a re-tune, was looking at a set of 262's at roughly the same price as a td06, unsure if i should downgrade turbo or upgrade cams
ali on February 05, 2012:
RB20 with turbo RB25 what you think??
ive 3" pipe,boost 0.6 and westgate 38mm....
sorry i newbie....:)
i want know your opinion....
Ben on February 04, 2012:
I've Always had subarus but loved the RB's so ive finally got one now, ive put a 2.5" performance exhaust on it, front mount, pod filter, platinum plugs. taken off all the bs like A/C P/S etc apart from that mostly stock. What would you recommend as the next fewbasic upgrade? eventually i want it as a street legal drift car :)
Dreaded Fist (author) on February 03, 2012:
The only way to increase the boost to 12psi is to use a boost controller, or use the various bolt ons like exhaust, intake and intercooler, which will naturally up the boost slightly. If you have a completely stock RB20, simply upping the boost t 12psi will make very little difference to power production, as the stock intake and exhaust restrictions will still be in place.
Ben on February 03, 2012:
Hey mate i was just wondering, ive got 20det and completely stock. Is the a way to adjust the stock boost to say 12psi without a boost controller or does you need it?
Dreaded Fist (author) on February 01, 2012:
Sorry about the delay in the reply: As far as camshafts on an RB20, they might work, but they might not. The general consensus seems to be that adjustable cam gears on the stock cams make a world of difference when adjusted properly on the dyno. As far as hurting the RB20, higher RPM's are no problem for it. The piston speeds with such a short stroke (69.7mm) are slow at the 7000rpm redline. At 7000rpm, the pistons are only traveling at 3,200 feet per minute. The general rule is that 5000 feet per minute is the absolute limit for a street car with the best possible engine internals, which the RB20 doesn't hit until nearly 11,000rpm. With a good tune, the RB20 will last all day long up to it's 7000rpm redline.
As for the oil pressure issue, if you are using the stock gauge, it's most likely reading incorrectly. The stock senders tend to fail fairly consistently. My own RB20 oil pressure sender is terrible, reading anywhere from 1 at idle to maxed out at full throttle. I recommend some type of aftermarket oil pressure gauge. Swoosh gauges on Ebay have good reviews from people I know, and are inexpensive. I'd say that so long as your engine is still running, the stock gauge is just reading incorrectly and you shouldn't worry about it. Grab a new OEM oil pressure sender if you like, but I'd spend the money on an aftermarket gauge instead. I would bet that your lifters are fine.
No worries about the questions :-) I enjoy talking about RB's with like-minded people. Most of the stuff I've learned about the RB20, I've just picked up over the years of owning one. I've had my Skyline since 2009 now, and have spent probably hundreds of hours just sitting on the computer reading and researching. I've also had lots of experience with my own car as well as local RB powered cars, so that's mostly where it comes from.
Adam A on January 09, 2012:
hi there, i really liked your post and feel it has brought light to my dark and expensive rb20det. i have spent thousands in upgrading and fixing. i had bought a kkr 4360 turbo, vipec ecu, bigger fuel pump new coils, hours spent on the dyno. and all for what?? makes me think i should have spent the money on an rb26 dett or something. but i pushed trough and persisted with the 20. I would like to know the benefits of new cam gears and new cams??? am i wasting my time with this engine? i don't have money to spend on $$ items, but can see myself getting more engine mods. the car is great after the 4000rpm mark but feels like im hurting her.. if u know what i mean. I can hit over 180 pretty well as ive had the limiter removed, but for what ive spent on her it should be a race car, not an everyday driver.. also oil is an issue, it seems to hit 0 when im on idle at a set of lights and 4 when im driving. what is that about? hydrologic lifters maybe? I know i have asked 100 questions but i feel u know your stuff when it comes to rb20's.. and why is that? cheers Adam A
Dreaded Fist (author) on January 03, 2012:
Hi Pierre, sorry about the long delay. Your engine could be suffering from blow by (http://www.bobistheoilguy.com/blowby.html), or from excessive oil being pushed out the valve cover breathers. If your engine spends a lot of time in the upper RPM's, your cylinder head will typically get a lot of oil sent to it. Some feel that the oil is unable to leave the head fast enough, causing it to be sucked out the breathers back into the intake piping between the MAF and the turbocharger.
What you could try to do is run a properly baffled oil catch can. Empty catch cans typically don't do anything but look cool, so make sure you source a baffled catch can. Most RB engines that spend a lot of time in the upper RPM range suffer from this problem. Most owners get a bit paranoid about it and overfill their oil by about 1 litre on track days.
If your engine is doing this frequently during normal driving, I'm not quite sure what could cause it. Perhaps blown rings, or valves, or another worn turbo issue?
pierre on September 12, 2011:
Great article, I have a little question. I just replaced my stock turbo on my rb20 because there was oil in in my intercooler and piping.Surprise It's still full of oil.Could oil come from somewere else than a broken turbo???? Need help, THANKS..
Mico on June 03, 2011:
Nice reading yr hub. http://www.micocrane.com/
Pat on May 24, 2011:
Dreaded Fist (author) on April 27, 2011:
@ hagibis18, I can verify that both the gt3071r and the gt3076r are great turbos for the RB20DET. They will suffer in the lower gears in the lower rpm range, but will add tremendous power in the higher rpms.
@allen, One trick you can try to bring your turbo on a little bit sooner is the addition of adjustable cam gears. You'll need some time on the dyno while adjusting them, but the addition can definitely bring the turbo on a little bit earlier when the gears are tuned properly. I've not heard about the T04E being used on to many RB20's. You could look into downsizing the turbine housing of the turbocharger if there are smaller housing available.
GT-Z from Amsterdam - Netherlands on March 11, 2011:
Great articles amigo and this one is no exception!
Thx for sharing!
gino on December 20, 2010:
hello everyone I just ran into this site ,don't know how 'lol' but I think that this is a very seriuos forum here you guys have......I must say.Anyway I am new to this whole RB thing,I have the stock RB25DET in the nissan altima.I am beginning to experience some hard starts and hearing a buzzing noise coming from inside the cold air intake which sounds like its coming from the turbo unit also after about 140km/h even while holding the throttle canstant the engine starts retarding on its own causing the speed to drop and feel like a natural aspirated engine and also comes along a lot of break-ups at this point.However I then have to open the throttle very lightly until it builds up.At this time all other small cars passes me with ease 'LOL'....FROM 0 to 140km/h she performs ok but after that there's no rush in reaching the higher speeds she takes her time even when I floor the pedal......can someone share some advice please.......thanks
Luke on December 08, 2010:
Seems to me like you need a 2.2 litre stroker kit to spool the turbo quicker and possibly more aggressive cams to force more air in
Allen on November 23, 2010:
Thumbs up for such a helpful guide you have there. I'm currently running a HKS T04E Turbo Kit (AR50) on th RB20, it seems like a big disappointment to me coz the turbo only start spooling at 4k RPM which is very lag for drifting purposes. On top of that I'm using Emanage Ultimate to tune up the ECU but it seems like there's a huge lack of torque below 4k RPM. Any ideas or solutions to improve the powerband below 4k RPM & make the turbo spool faster? Hopefully you can solve my problem & bring back my drifting life. Cheers, Allen from M'sia.
hagibis18 on October 26, 2010:
very helpful guide, just wanna add up gt3076r or 633071r is a nice turbo upgrade for daily driver/track car
ajaroslav on August 15, 2010:
Im running the RB25 turbo and can vouch for it as a reliable low cost upgrade. Low end is great with power coming on quickly. They can be found on eBay at bargain pricing....just be careful and don't buy another RB20 turbo.
Oscar on August 06, 2010:
Great knowledge thanks heaps very help full
silvatroll on August 06, 2010:
Do you think that the RB20det is too small for a standard sized car, say a VL commodore? I know the RB30 was the stock option.
danielmarshalls from Los Angeles, CA on August 04, 2010:
Amazing.. I found the post very helpful.
Evan on August 02, 2010:
Hi there, very nice article u got there, gives me inspiration to keep my RB20. Ive been using mine for a little less then a year. So far so good. Im still not sure if i want to upgrade this engine or swap with an RB25 or 1JZ. All depends on the cost effectiveness. Aftermarket parts here in Malaysia cost a bomb even 2nd hand! :(
Just one question, Bu tin your article, its mentioned that a stock turbo with 1 bar boost can achieve 268hp! Mine is only doing 215 Hp on the wheels with a 1 bar tial wastegate (Vent to atm), Open Pod K&N Filter and Blitz ECU. IS there anything im missing? Thanks!
Ramzy on August 02, 2010:
what's the going price on the td06 20G kit
Ramzy on August 01, 2010:
what's the price of the td06 20G kit
Dreaded Fist (author) on June 27, 2010:
@Mike240 Sorry I didn't get back to you sooner, life is a busy thing, sometimes! As far as the Emanage goes, I think it's great for bolt on engines. I don't know if I would want to use a piggyback ECU with bigger injectors or something like that, I don't have any real reason why, though. I think if you're doing lots of bolt ons, say a 3" turbo back exhaust, an intercooler, air filter and boost controller, it'd work great. Because you can optimize the setup without worrying about more complex things like injectors or turbo air flow numbers. A good tuner would be able to maximize the effectiveness of bolt ons, as well as improving driveability and fuel economy as well.
mike240 from ASTORIA N Y on May 25, 2010:
man it took me like 20 mins to make a hub acount...but i did it cuz of your article lol...great info..thankyou so much you don't know how much u just helpped lol
do you know anything about this emanage piggy back ecu thing
shy32 on April 02, 2010:
Great article! without all the bulshit. doesn't give you idea..it gives you answer. which is what people is looking for. thanks.
Saiful on March 17, 2010:
That really helps me out. Cheers and good luck. I will keep a constant lookup for your post. Its informative and simple to understand (Yeah it sound kissing ass but I MEAN IT!!)
Dreaded Fist (author) on February 26, 2010:
1) When uprading to a bolt-on turbocharger on the RB20, you may need to swap out the piping, depending on the size of the turbocharger. In some cases, a very large T3 that bolts to the stock manifold might not be compatible with the stock turbo outlet or downpipe, and may require custom hot side intercooler piping, or at the very least, modified stock poping.
2) I've heard of people using the VG30 turbo on an RB20 before, but I don't know anything about the VG20 turbo, so I cant give you any advice there. The VG30 turbo's are apparently getting harder to find. They also have a reputation for being a poor match to a street driven RB20, as they apparently don't come alive until a bit later in the rpm range. I've heard that they don't begin to really start working well until 3500rpm.
3) As for the lack of torque below 4000rpm, there's a few things that can be done to improve the situation. An ecu upgrade (even just chipping the stock ecu to give it standalone tuning capabilities, like Nistune does) can give you the ability to play with the ignition timing and fuel maps, which should in theory allow a good ecu tuner to improve the low end torque. I think for the absolute best improvement below 4000rpm, the stock turbo should be used, with boost set to 12-14psi (around 0.8 to 1 bar). When combined with a very good ECU tune, the stock turbo can really improve the available power below 4000rpm. The stock turbo is really only safe to about 12psi (0.8 bar) however. It can survive at as much as 1 bar of boost (14.7 psi I think) with an ECU tune that runs a bit rich, in order to keep the exhaust gas temperature low. The reason the stock turbo's tend to fail past 12psi is exhaust temperature, which fatigues the ceramic turbine wheel. A richer air/fuel mixture allows for cooler exhaust temperature, which in theory should allow the stock turbo to survive past 12psi.
4) I've been thinking about getting around to making an rb20 camshaft upgrade article, but I'm still doing some reasearch for my own purposes on all the available camshaft upgrades and what they'd require. When I publish the article, I'll link to it in either these comments, or in this article itself.
Hope this helps!
Saiful on February 04, 2010:
Hello, nice article u have here. Do you mind if i land u some questions?
1) If i want to upgrade similar to bolt-on without additional working on piping what is the criteria i need to know? If the turbo is using T3 flange is enough or there is something more?
2) Some say the cheap upgrade would be RB25DET Turbo. What about VG20 and VG30 turbo? What's your opinion on these turbos?
3) Does installing piggyback (E-Manage) or standalone (Haltech) could cure the below 4000rpm syndrome?
3) We (or me) would like to hear more about the camshaft upgrade. What kind of work needed for this upgrade?
tyson on January 27, 2010:
this site is great i was a v8 man b4 this just bought a s13 sylvia with rb20det conversion i plan on working this engine to its limits i have a greater understanding now good work mate im looking forward to hearing more in the future
drift king on January 19, 2010:
just learnt a lot about my engine thanks for the wisdom..
carlos v. on December 06, 2009:
this was very help full for me all of this info great to know about my engine will up grade my turbo soon for one of the recommended on this site..
Dreaded Fist (author) on November 19, 2009:
Lol thanks, I appreciate it. I figure I've been having a heck of a time trying to find a good turbo upgrade for my RB20, so maybe I should help some people out :)
Dad2401x1 from California on October 14, 2009: