Jump to content
SAU Community

Recommended Posts

hey,

it's been a long time coming, thought i'd get the ball rolling on to get this into a sticky to stop all these threads popping up. i'll need your help on this guys (yes i'm looking at you; jarrod, cris, nick, ashley, rachael, scathing, skit, etc).

we need to elaborate on each section and your input on what errors i've made (if any ;) ), and add to a general wikipedia type of thing. if anyone can write up a quick section we can all contribute to expand it.

updated links, search results, etc. would be helpful

cheers

eug

points to address:

- rb30de

- rb25de into an r32

- brake upgrades for na skylines

- individual throttle bodies

-----------------------------------------------------------------------------------------------------------

How to get more power from a naturally aspirated engine?

There are many ways to get more power; it all comes down to budget and application.

Power is defined by the rate at which work is performed over a unit of time. Used in our context, power will represent the maximum kilowatts (kW) a vehicle produces as measured on the dyno. However, the key factor in the above equation to take into consideration here is 'time', which is essential for 'response'.

Being a naturally aspirated, the motor is neither turbocharged nor supercharged. This means that the motor relies on vacuum created by the cylinders and natural atmospheric pressures to draw in ambient air for combustion.

In order to get more power you will have to rely on the basic principal of: letting the motor breath/work better, so to speak. This is done by removing the restrictions within the system and thus creating more efficiency.

Here is a basic list of what can be done, we shall elaborate on them at a later stage:

  • Intake (pod filter, panel filter, larger throttle body, cold air feed)

    [*]Exhaust (extractors, cat converter, cat back exhaust)

    [*]Motor (shave the head and/or block to increase compression)

    • Head

      • Port and polish (remove restrictions in the head)

    • Oversized valves (allow more air to flow)
    • Cams (regrind, intake and exhaust side to improve breathing)

    • Gasket (thinner gasket to increase compression ratio)
    • Block
      • Pistons (increase compression, light weight)
      • Crank (light weight)
      • Rods (increase compression)

  • Electronic Control Unit (ECU)
    • Piggyback systems (SAFC, E-Manage, GTS-Link, allow modifications of engine parameters; air:fuel ratios, timing, etc.)

  • Drivetrain
    • Flywheel (lightened to decrease unsprung mass)
    • Tailshaft (one piece, carbon fibre; lightened to decrease unsprung mass)
    • Rims (lightened, forged)

  • RB25/30DE and RB26/30DE Hybrids
    • A good and useful NA motor has larger power band, this means the car is able to put down significant amounts of power through a large rev range. This is achieved by an increase in cc's -as in an RB30DE and the compression ratio*. High performance NA motors run high compression ratios (CR) to give more torque and power through in the low rpm range, this will see the motor rev faster. In the RB30DE hybrid a significant amount of the extra power being made is gained via the head, so particular attention to this area is ideal.
    • Block: RB30E NA block (Found in R31s and Holden VLs)
      • Capacity: 2982 cc
      • Bore: 86.0 mm
      • Stroke: 85.0 mm

      • The RB30 crank is nitrited standard and is strong enough to withstand a mild increase in kW.
      • The RB30 rods are suitable for simple low - mid range and mild CR motors. However aftermarket items are required for motors looking to do beyond 6500RPM, as the standard items will snap and/or crack.
      • RB30 or RB25DE pistons are able to be used. **yet to be confirmed & CR using RB25DE pistons** Using the stock RB30E pistons will give you a CR of ~8.2:1. This can easily be increased to 9.5 - 10:1 (by shaving the head, ~2mm shaved) depending on fuel availability for regular street use. It is possible to run up to 12:1 CR before you need to switch to race fuel to prevent pre-detonation (aka pinging).
      • Cam belt tensioners needs to re-positioned. Using a tensioner and idler the timing belt tension to be greater than the factory recommended spec of 20kg's. You can use a second tensioner in place of the idler bearing in order to bring the belt tension down to the factory recommended spec of 20kg's. It is possible to use the factory tensioner and idler locations however, you will be required to use two tensioners to get the correct belt tension. Some do not recommend this method as the belt comes too close together.
      • A 152 tooth 20kg timing belt must be used.
      • All RB26, RB20, 25 and RB30 water pumps and thermostats are interchangeable.
      • It is best to use an oil pump from a twin cam motor as these provide more flow and pressure. All RB oil pumps are interchangeable. The RB pumps do have a reliability issue and are prone to cracking if used at revs over 6500rpm without a crank collar. A good supply of oil is required for high rpm applications.
      • Whilst the RB30 does have a strong bottom end it may need a freshen up as many of these engines have done over 200,000km. If you're chasing big power out of an RB30DE you will also need to think about:
        • Bearings: ACL race bearings
        • Rings: Molly ring sets or stock alternatives
        • Balancing: Best done with the harmonic balance, clutch and flywheel attached.
        • An oil cooler, oil pressure and oil temperature gauge may be required for high rpm applications.

      [*]Head

      • R32 RB25DE, R33 RB25DE, RB25DET, RB26DETT (NVCS and Non-NVCS)
      • Rb20DE/T heads will work with modification. (Link to RB30 PDF)
      • RB26DETT heads have the best flow. They also run multiple throttle bodies which are ideal for NA motors. An adaptor plate is required to attach Rb26DETT throttle bodies to the RB25 head.
      • RB25/26 heads have cc capacity of around 62-64cc's, in comparison to the RB30 55-58cc's
      • All coolant/oil galleries line up between the block and the head without any issues.
      • An oil feed from the block to the head using a T-piece is required to maintain NVCS.
      • Upgraded valve springs may be required for high power applications (See section x.x).
      • Standard camshafts, reground or aftermarket items are available (See section x.x).
        • The max regrindable standard cam profile is 8.3mm & 255º. Remembering that Lift = torque and duration = power.
        • GTR camshafts can also be reground to use hydraulic lifters. They are a recommended budget upgrade. (See section x.x) *to confirm

        [*]Adjustable cam gears/pulleys are recommended if using modified/aftermarket camshafts.

        [*]Port and polishing is recommended if looking for both power and response.

      [*]Flywheel

      • All of the RB20 and Rb25 flywheels are interchangeable.

      [*]Engine Mounts

      • The RB30DE block is approximately 38mm taller than the other RB blocks.
      • Engine mounts will need to be modified to lower the motor by 15mm on the driver's side and 12mm on the passenger's side to allow for bonnet clearance if maintaining the standard RB25 intake plenum.
      • The lower lip of the radiator may need modification to allow for fan clearance.
      • Gearbox and center bearing mounts may also need modification to reduce driveline angles.

      [*]ECU

      • RB25DE stock ECUs may restrictively be used, they are not mappable
      • If utilizing NVCS an appropriate ECU is required.
      • RB20 ECU is able to be chipped for RB30 use. *to confirm?
      • NA Z32 (300ZX 3L V6) ECUs are mappable and can be found with VCT variants and are more appropriate. *confirm?
      • Apexi SAFC can be used to tune air/fuel mixtures
      • Aftermarket stand alone ECU's (MoTec, GTS Link, Apexi's Power FC etc.) will be needed for high power applications

      [*]Results (http://www.skylinesaustralia.com/forums/Na-Power-Results-N-a-E-t138169.html)

      • GTS_143
        Model: R31 GTS2
        Engine: Rb30DE
        Modifications: VCT, mild cams, ported head, lightened & balanced bottom end, big extractors & full 3" exhaust, 12:1 compression, twin XF TB's (throttle bodies), pod & CAI, twin thermos, spitfire coils, Link ECU.
        Power:149RWKW

      • SKiT_R31
        Model: 1987 R31 Skyline Ti
        Engine: RB30DE with VVT
        Modifications: Extractors, exhaust, twin tb, safc untuned, billet f/wheel, reground surecams, 10.5 compression, 18 degrees timing, 98ron ultimate
        Power: 150.9RWKW @ 172kmph an 507nm (374FtLb) torque at 144kmphR

    [*]Forced Induction (not considered naturally aspirated, although nitrous is debated)

    • Nitrous Oxide (NOS or N2O, injected into the intake to increase oxygen content during combustion.
    • Turbocharging (exhaust gases used to create intake vacuum to compress and increase oxygen content for combustion)
    • Supercharging (crankshaft energy used to create intake vacuum to compress and increase oxygen content for combustion)

*RB30 data collated from information gathered from the RB30 thread (http://www.skylinesaustralia.com/forums/R33-RB30-Conversion-t15420.html) and Cubes's RB30 PDF.

The power of an NA engine is larger power band. This is achieved by an increase in cc's -as in an RB30DE and the compression ratio. High performance NA engines run high CR's as this gives you better low down torque and will push your engine in high RPM faster. Much of the power being made will be gained via the head. So pay much attention to this aspect of the engine.

RB30DE (3L Double over-head cam):

Made by using an RB30E and an RB25DE head

Block

- RB30E (2982 cc, bore: 86.0 mm, stroke: 85.0 mm) NA block (found in R31's and Holden VL's)

- The Rb30 crank is nitered and is strong enough to cop a fair few KW

- Rb30 rods are ok for a simple low - mid power/CR engine but will need to be replaced with aftermarket items once you get cams as the engine will be reving to far beyond what the rods were designed for. Stock rods wont take much more than 6500RPM. Aftermarket rods will stop you from throwing a con rod/snapping/cracking at these high rpm’s.

- You can use RB30 or RB25DE pistons. - **yet to be confirmed & CR using RB25DE pistons** Using stock RB30E pistons will give you a CR of ~8.2:1. This could easily be bumped up to 9.5 - 10:1 (~2mm shaved) CR for regular street use. It is possible to run up to 12:1 CR before you need to switch to ethanol fuel where high CR's can be achieved.

- Cam belt tensioner needs to re-positioned. Using a tensioner and idler the timing belt tension to be greater than the factory recommended spec of 20kg's. You can use a second tensioner in place of the idler bearing in order to bring the belt tension down to the factory recommended spec of 20kg's. It is possible to use the factory tensioner and idler locations however, you will be required to use two tensioners to get the correct belt tension. Some do not recommend this method as the belt comes too close together.

- A 152 teeth 20kg timing belt must be used.

- All GTR, R32 RB20/25 & VL/R31 RB30 water pumps and thermostats are interchangeable.

- It is best to use an oil pump from a twin cam motor as these provide more flow and pressure. All RB oil pumps are interchangeable. The RB pumps do have a reliability issue and crack if used at 6500rpm+ without a crank collar. Therefore, for a high revving NA engine where much of the power is found in NA head a crank collar is a MUST!

**Note** While the RB30 does have a strong bottom end it may need a freshen up as many of these engines have done +200,000km's. If you’re chasing big power out of an RB30DE you will also need to think about:

- Bearings - ACL have race bearings

- New rings - Molly ring sets or stock alternatives

- Once the bottom end is back together the engine will also have to be balanced. It is best if this is done with the clutch and flywheel attached.

- During track work and high temp conditions people have had problems with oil temperatures. An Oil gauge is recommended and oil cooler accordingly if needed.

A cheap and low power 3L bottom end can be had for ~$500

A high power/high comp bottom end will need (excluding previous work) ~$1500 - ~$2000

Hardcore Race engine ~$3000 +

Head:

Rb25DE/RB25DET/RB26DETT VCT/NON- VCT

- Rb20DE/T heads will work but with much machining which is expensive and will also have smaller ports making this an unfeasible option.

- Rb26DETT heads are best flowing. The intake manifold also has more than one throttle body. An adaptor plate is needed to attach Rb26DETT manifold to RB25 head.

- Rb25/26 heads have cc capacity of around 62-64cc's. Compared to the RB30 55-58cc's

- All coolant/oil galleries line up without a problem

- If your using a VCT head and wish to keep VCT you need to run an oil feed to the head using a T junction from somewhere in the block/sump.

- R32 Rb25DE head studs will work without a problem

- If your chasing higher power will need RB25DET valve springs as they are stiffer than the Rb25DE

- Stock cams will work fine or you can buy aftermarket cams or get your stock cams re-grinded. The max regrindiable stock cam profile is 8.3mm & 255deg. Remembering that Lift if torque, duration is power. Adjustable Cam gears are recommended if using modified cams. GTR cams can also be regrinded to not use lifters **need to confirm** and are a cheap up-grade.

- Port and polish is recommended if looking for power/response. Polish can be done with Brevil style drill and can be done in the backyard. Same with porting, yet for optimum performance, professional work is required.

- Rb25 Exhaust manifold/headers can also be used in this application.

A cheap stock Rb25 head could set you back ~$750 - $1000 (cost of head)

A mildly modified head (excluding head) ~$700 - $1000

A heavily worked head (excluding previous work) ***(?????)***

Flywheel:

- All of the RB20 & 25 Flywheels are interchangeable.

Engine Mounts:

- The RB30DE block is approximately 38mm taller than any of the other RB blocks.

- If you want to run the stock RB25 inlet manifold/plenum you will have to lower the engine by 15mm on the driver’s side and 12mm on the passenger’s side. You will then be required to remove the lower lip of the radiators shroud otherwise the fan will munch it up. It is worthwhile to relieve the gearbox and centre bearing mount slightly. In an attempt to reduce driveline angles to an absolute minimum.

ECU:

- Once headwork is done and to extract more power a re-tune is required.

- Rb25DE stock ECU's can be used but power will be limited. These ECU's are not mappable

- If utilizing VCT an appropriate ECU is needed.

- NA Z32 (300ZX 3L V6) ECU's are mappable, can be found with VCT variants and are more appropriate.

- Apexi SAFC can be used to tune air/fuel mixtures

- Aftermarkety stand alone ECU's (MoTec - Apexi's Power FC etc.) will be needed for high power applications

Results"

**taken from power results stickie thread**

GTS_143

Model: R31 GTS2

Engine: Rb30DE

Modifications: VCT, mild cams, ported head, lightened & balanced bottom end, big extractors & full 3" exhaust, 12:1 compression, twin XF TB's (throttle bodies), pod & CAI, twin thermos, spitfire coils, Link ECU.

Power:149RWKW

SKiT_R31

Model: 1987 R31 Skyline Ti

Engine: RB30DE with VVT

Modifications: Extractors, exhaust, twin tb, safc untuned, billet f/wheel, reground surecams, 10.5 compression, 18 degrees timing, 98ron ultimate

Power: 150.9RWKW @ 172kmph an 507nm (374FtLb) torque at 144kmph

Did I miss anything?

Comments/Abuse/flame/Advise is all welcome! ;)

Edited by GTS4WD

Hey guys,

I am new to this site and live in the Campbelltown area. Just wanted to say that this seems like a really promising thread and I look forward to get to knowing you all..

  • Like 1

LOL!.. sorry guys!.. I guess I got a bit too excited about doing something.. :glare:

http://www.skylinesaustralia.com/forums/Z3...69#entry3264869

See post six

http://en.wikipedia.org/wiki/300zx

See 1996 development one..

updated.

parts in red require clean up or more attention.

i would also like to cite references.

cris, i've re-worded some of your sentences and removed some parts otherwise it was just going to be way too big. some parts such as camshafts, etc. can be referred back to one section. especially with the rb30 section it will sometimes double up.

the costs and stuff are quite variable - as long as we're able to provide the core details it should be starting point.

thanks for contributing, hope you can add some more - any section you're not happy please let me know and we'll fix it.

wonder if we can get a wikipedia board put into this section? would be a lot easier.

Im going to have a tackel at some of the intake mods.

Items to address. Pod filters, panel filters, cold air induction, larger throttle bodies, air flow meters.

The aim with an na engine is to make it breath as much cold air as possible, the more air that the car can suck the more power you can make.

Upgrading Panel filters are good because they still use the standard cold air intake whilst providing extra flow. they are good for a starting mod as their easy no mod instalation but when looking for huge power figures the standard air box/cold air feed will not provide enough air

Upgrading to a pod style filter can be the best sucktion upgrade you can do or the worst. Theres been lots of tests done to which pod filter suck's and filters best heres one example of higher end filters. http://www.mkiv.com/techarticles/filters_test/2/index.html. Now if these filters are just tacked onto your intake after the a/f meter they suck in lots of hot air and can actually loose power. The only effective way to run a pod filter is to run it with some type of heat sheilding.

There are sevral different ways to run your heat sheiding, you can just run some sheilding over the section of the pod which is most exposed to heat, the other way to do it is to run some sort of separation box or compleatly inclosed box.

On top of heat sheilding to run a good intake you will need some sort of cold air intake, the more cold air the better. There are so many options to how to run your cold air pretty much you need to run some sort of pipeing from the front bar up to your pod or panel filter. You can go over the headlight like the standard one but try and run a wider mouth or you can feed it up from the bottom, you could do this effectivly by cutting a hole where the standard turbo intercooler piping normally goes. There are provisions for the holes already there and this will not take from the strutural integrity of the chasis.

Larger throttle bodys. Best option most people go for is the xf throttle body. it either65 or 68mm cant remmeber. there are other options but the xf one seems to be the best size and ease to fit. Throttle body mods wont normally give you much of a power increase but they increase responce as the car can only breath as much as the capacity of the engine when on full throttle. there was some disscussion into 90mm Q45 throttle body but they are too big.

its best when putting a bigger throttle body on to increase all piping size to suit including the a/f meter otherwise you will create air flow restrictions.

This link is a guide on how to fit an XF throttle body to an rb30 but can be applied to all rb's.

http://wiki.r31skylineclub.com/index.php?t...F_Throttle_body

This is a guide and disscsion on twin throttle bodies/a/f meters

http://www.skylinesaustralia.com/forums/2-...throttle+bodies

Not best wording but the links will be usefull :glare:

where abouts is the intercooler piping spot where you can cut through to make a cold air intake? i havnt really looked at this on a turbo r33 can someone point it out on a pic or something? might have a look at this tomorrow.

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



  • Similar Content

  • Latest Posts

    • I did read your post, a few times actually.    Done. Followed this step. [Negative probe should be on the cars chassis. Positive on the wire.]   Did this partially.. now that im reading this over, i only unplugged the LED lights. [Start as said above by unplugging everything (unplug the lights, and switches.] When you are talking about the switch, you're talking about the knob thing on the right side in the drivers seat right? If so, i need to take that apart?  [Now at the switch, there is a wire from the fuse, to the switch, so out your positive on that terminal. It should read open circuit. If it reads something, especially a stupid low value, the short is somewhere between the fuse and the switch.] At this point are you referring to the connector by the headlights?  [If that's fine, now put the positive probe on the wire that goes to the headlight (at the switch plug). If it reads stupid low, the fault is from the switch, to the headlight.] Did this. I can confirm that the LED lights aren't the issue [Another quick test, is take the whole LED light setup from the left, and plug it into the right side, does it still blow the fuse? If you put the right hand side led light setup on the left hand side wiring, does the left hand side wiring now blow?  If the blowing fuse swaps from right to left doing this, your LED lights are the issue.]
    • Hey was wondering if you ended up installing the R33 GTR speed sensor - I found one too and wanted to confirm it's a direct swap into the R34 6 speed?
    • After 23 years of owning a Skyline, finally had the latch go.  Followed this guide,  works like a dream again. Great Guide 👍
    • Hi all,   I’ve got the biggest lot of problems with my R33 GTS-T   It was a freshly rebuilt 25th anniversary RB25DET (plastic cas, neo cams) probably 6 years ago now   The engine was running so well but I fkd up badly and trusted someone I’d known for 10 years that was well known around Plazmaman for his welding and fab work. I added a lovely photo of some of his previous work. Not sure why my car was worked on by whoever did this shit     I’m normally someone who would never open myself up to something like this, I still can’t believe I did it. Trusting him literally fkd it all up for me. Everything has been a struggle, like it’s almost been 6 years that’s how much I’ve just on and off been trying to work it all out.    All I wanted was a car that danced down low, like full boost from around 3~3500rpm to redline, don’t really care what power it puts down (if it ever does) but I just wanted it to be quick to get on it.    He recommended the turbo to get, I picked Hypergear but he told me to get the front 4” with a T4 and 0.68 rear housing.    I was expecting all these beautiful welds, tidy fab work and paid for it to be ready to go to a tuner when I got it back.    I got a car back that was an absolute mess, I actually couldn’t believe it was my car anymore. I don’t think you could even call what he did welds, they’re disgusting.    So I stripped everything he touched off it and with every bolt I loosened it just got worse and worse.    I covered it and literally built and finished another car in the meantime but now it’s getting to the point where I really want my Skyline back.   Its a struggle because I paid him to do all this shit because I didn’t know how to and now I’ve had to try and figure it all out omg    Please excuse the bird shit horrible welds, I’ve got my show pony car and am so beyond dealing with this car I don’t even really care at this point.    If someone told me about what he did to my car I wouldn’t have believed them but it happened to me. It was unbelievable. He went missing, my car went missing, it came back missing parts, the straight af chassis rails bore the scars of being dragged up a trailer backwards, even the sandwich plate was bent. Everything was leaking and open to whatever fell into it, rounded off/ missing bolts, power steering oil and coolant everywhere, no gaskets, parts stolen off it, even managed to damage the sump pan.   Promised me he’d finish the car, knew what it meant to me, I paid him thousands and thousands just for him to trash it. He told me he was fully licensed and insured, come to find out he’d cancelled his ABN, so obviously no insurance. I had laid up insurance on the car and would’ve been covered but I was scared they would’ve written it off or because the business was no longer trading I’d still be liable.    He was supposed to:  New fully custom mild steam pipe exhaust manifold with turbo location moved from factory position to high forward mount. (I don’t know if it is a mild steam pipe, I’ve got a funny feeling the waste gate isn’t in a very good position and I don’t think the outlets off each cylinder are equal) 4” custom stainless steel dump with external gate (he re-plumbed it) Cut and shut OEM intake manifold with throttle reposition (I ended up doing the throttle reposition) Box in pod filter (left out) New 100cel catalytic converter (pretty sure it’s there but unsure if it’s 100cel) Front mount intercooler piping fabricated to suit (all smashed up and rusty holes where he was supposed to make it look standard where fmic piping passes through. I don’t even think my front bar is going to fit 🙄) Custom 5” intake pipe from pod to turbo (didn’t come with it so had to do something to make it work with the Z32 afm)   Engine: Full cylinder head service & machining  Brand new valves Precision upgraded spring kit Engine block honed New bearings  New piston rings  New ARP conrod bolt kit New ARP head studs Cometic head gasket VRS kit   ATR43SS2 ball bearing turbo 0.68 rear housing  Turbosmart 45mm external wastegate (got delivered to the fab bloke, I’ve got no idea what spring is in it, I’m assuming the one that came pre installed) Walbro 260 fuel pump  Nismo 740cc injectors (tested to 880) Spitfire coil packs GCG FMIC RB25DET manual 5 speed 4:11 rear diff   I’ve got an Apexi Power FC in it atm, I was hoping to just get it to operating temp to make sure everything was okay before towing to a tuner but it’s over-fuelling too much. I don’t think that’s going to happen so i think I’m going to get either a Link G4 or Haltech for it. What do you guys recommend? I can’t work out the power FC so just gonna give up on that one     It’s got an exhaust leak coming from somewhere I can’t see 🙄    The fuel pressure was steady but now it like drops from 40 to 20psi randomly (noticed this yesterday)    I’ll attach pics of the shit he put on my car and the engine bay now as it sits    I really just need some help, I need a tuner in Sydney I can trust, I’d like to be with the car while it’s being tuned if possible, I know it looks terrible but unfortunately I’ve just got to put up with it for now and fix the cosmetic stuff later   Do you guys think the manifolds are going to be okay? Or do I throw the exhaust manifold and try again?   I don’t even think these combinations are going to work tbh   I know everything I fitted was rated to be able to take at least 400kW but most rated higher    If you’ve gotten this far I really really appreciate it 🙏 I don’t mind if you trash me or the car, I made a rookie error and f**k I’ve paid for it. As you’ll see 🙄  
    • From everything I’ve heard you’ll be waiting a long time for  the parts to arrive 
×
×
  • Create New...