How To Get More Power From A Naturally Aspirated (na) Engine

[Hesh]

I gotta jump in here in defense of lammy.

since finding this forum i have been lobying (successfully) for an NA section on the UK skylineowners.com. since here in the uk there are considerably less NA's knocking around, we have adopted an information gathering aproach to what can be done to an NA, which of course includes addition of a turbo or a supercharger. (ok so they then become forced induction but bear with me)

The reasoning is simple. over here alot of the turbo lads were of the opinion that its cheaper to sell the NA skyline (in this case the rb25de) and buy a turbo model..however lammy has done the conversion so can say with authority that it simply isn't the case. Additionally the turbo'd de is a different beast due to the compresion ratio's etc.

so in short Lammy's post was in the spirit of "what can be done to an NA", thus hopefully convinceing a few people to go down that "road less travelled"

I for one will be interested to see how long the bottom end lasts and what power figures are acheived before it goes pop.

for how else will we learn?

cheers si.

Edited November 10, 2008 by Hesh

[N-DAWG]

A number of people have done the DE+T conversion with good long-lasting results. If not I wouldn't be doing so myself.

666DAN got approx 70,000kms out of his R34 before the car got stolen; WYTSKY has been successful with his R33 and he's pushing some big boost for stock internals!; DORI32 and myself are in the process of gathering parts to do the conversion on our R34's....so long as it's tuned properly, you take the right steps to ensure it's getting nice cool air, and you're not flogging the balls of it at every intersection, it should live a long and prosperous life.

How I see it, my car has around 111,000kms on the clock. If I get even 70-80,000kms out of it that will be excellent! Cause by then I'd be ready to say, ok, engine rebuild with forged high comp internals, bigger turbo, upgrade the other necessary bits, and all the ground work will have already been laid out with the initial bolt-on conversion.

The result? More power with the initial conversion, with even more room later on to build it into a rock solid turbo engine.

As for power levels, this really depends on how far you go with it, FMIC, High flow pump, injector capacity etc.. and of course how much boost you're willing to push through it.

Yeah you can run high boost, don't expect it to last. Run ~7PSi, combined with high comp, you'll get the down low torque of the high comp, and from what i've read it will come on boost at 1800 and throw you into your seat at 3000revs.

Either way you look at it, you'l get more power for the dollars spent on a turbo conversion than the same dollars on keeping it N/A. It all depends on whether you want a turbo or if you're happy with or prefer an N/A car. For some N/A is all they need / want and that's fine.

Lammy's post was probably better seen and more useful in the how to turbo an N/A thread than this one.

I gotta jump in here in defense of lammy.

since finding this forum i have been lobying (successfully) for an NA section on the UK skylineowners.com. since here in the uk there are considerably less NA's knocking around, we have adopted an information gathering aproach to what can be done to an NA, which of course includes addition of a turbo or a supercharger. (ok so they then become forced induction but bear with me)

The reasoning is simple. over here alot of the turbo lads were of the opinion that its cheaper to sell the NA skyline (in this case the rb25de) and buy a turbo model..however lammy has done the conversion so can say with authority that it simply isn't the case. Additionally the turbo'd de is a different beast due to the compresion ratio's etc.

so in short Lammy's post was in the spirit of "what can be done to an NA", thus hopefully convinceing a few people to go down that "road less travelled"

I for one will be interested to see how long the bottom end lasts and what power figures are acheived before it goes pop.

for how else will we learn?

cheers si.

[Hesh]

thanks n-dawg, your post was great and actually serves two purposes.

i agree that perhaps lammys information may have been better in the specific section "how to turbo your NA" ....

BUT..also

the mere fact that this forum HAS a "how to turbo your NA" specific thread says volumes about how you guys view NA skyline varients. when i first aquired mine and began the learning curve, over here in uk there were almost exclusively dismissed as not worth bothering with.

hopefully once attitudes change a little over here in the uk...(which has to some extent happened) then we may get to a situation where turbo'd NA's are seen as "nothing new" or a standard sort of mod. you guys are some way further down that road than us.....

hence the reason i've been shamlessly reading allthe info on here for the past 2 years....lol

Edited November 17, 2008 by Hesh

[Dhiv-Zilla]

Thanks,

Now I've got ideas for my NA

[DaGr81]

My lines pushing 200rwkw and it's been 2 years now since the de+t conversion!

[bighags]

hey guys i own a 31 executive i already have a full exhaust with high flow cat, lukey extractors and the whole thing is 2.5 all the way back , i also got a my pod in a decent spot but i need more power and i was wondering if an upgraded ecu would make all that much difference, power for money wise with the proper tuning costs and everything. plus i was wondering if anyone knew where i could get a cheap lsd and 5 speed box and everything needed for a full conversion. cheers bighags

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)
  • Neat Cold Air Intake
    
  • Professional Looking Heatshield
    
    

  [*]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.

[STATUS]

My lines pushing 200rwkw and it's been 2 years now since the de+t conversion!

should not be a problem like youve said, we have a few pushing mid 200's all with no issues. I even have a 34 with over 100hp of nos being injected.

[nxcusnmcfghssdfasegwrg]

nice write up.. helped me heaps

[WYTSKY]

I feel sorry for u...... mashed the keyboard a little bit when choosing a username did we?

[MissR34]

[N-DAWG]

should not be a problem like youve said, we have a few pushing mid 200's all with no issues. I even have a 34 with over 100hp of nos being injected.

R34 N/A with 100hp NOS? or R34 N/A+t with 100hp NOS? Keen to see that!

lol @ nxcusnmcfghssdfasegwrg

[MissR34]

ive done R34 N/A with 100hp shot of nos

[Ethan-33]

bro our a ledgend just what ive been looking for EVERYWHERE

cheers.

[panasonic]

Thank you, for answering. But this method works for me only with .. In all other cases I get only strange results, like those below

comparatif simulation taux credit auto - Taux crédit auto. Comparatif des offres! Les meilleurs taux crédit auto sont sur le net !comparatif simulation taux credit auto

[G-junkie]

Thanks for the write up mate! This will sure come in handy for the new p plate laws im under.

[mwboom]

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.

fit the turbs boys

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!

[Gerg_R31]

Compression ratios

There seems to be little idea on compression ratio's or how to get the desired compression ratio. Taking X amount off the block and X amount off the cylinder head will raise the compression ratio but how much is actually just guessing. There is a lot of measuring and working out how much to add or take out grind off from where.

A lot of the figures I have used is from my RB26/RB30 I have been working on at work, I have used JE 0.040" over sized pistons and a "ACL Race Series" metal head gasket

Below is the formula

Bore x Stroke

bore x bore ÷ 4 =

87 x 87 ÷ 4 = 1892.25

Answer x stroke x π (pie) =

1892.25 x 85 x 3.142 = 505363.2075

answer ÷ 1000 =

505363.2075 ÷ 1000 = 505.363208 = SV

answer x number of cylinders = cc

cc ÷ 1000 = litre

Head Gasket

Same formula as above though a this part is quite often left out

gasket bore squared ÷ 4

87.5 x 87.5 ÷ 4 =1914.0625

answer x gasket thickness x π (pie) ÷ 1000

1914.0625 x 1.3 x 3.142 = 7818.179688

7818.179688 ÷ 1000 = 7.81818 [ + ]

Head Chamber CC

Using a burette cc the head, grind 0.010"/0.25mm off and work out how much that has removed and then work out how much more you need to take off to get the desired chamber volume

Ill add to this when I get an X amount of how many CC's removed per 10 thou grind

I'll be aiming for 58cc

Piston Dome/Dish /dome with valve releifs

They can vary a lot, most piston manufacturers will say what cc they have

mine say 10cc Dome [ - ] Dish [ + ]

Deck height

This is the measurement from the deck to the top of the piston (not top on the dome) when the piston is at TDC

If the piston is below the deck

bore x bore ÷ 4 =

87 x 87 ÷ 4 = 1892.25

= x deck to piston x pie ÷ 1000

1892.25 x 0.3 x 3.142 =1783.63485

1783.63485 ÷ 1000 = 1.783635 [ + ]

0 Deck height is 0

Piston above the deck (0.017"/0.43mm for this set up)

top measurement of the piston squared ÷ 4

86 x 86 ÷ 4 = 1849

= x piston to deck x pie ÷ 1000

1849 x 0.4 x 3.142 = 2498.10994

2498.10994 ÷ 1000 = 2.49811 [ - ]

Adding it all together

Head CC + Gasket volume

then the following options

+ Piston Dish

+ Piston below deck

- Piston Dome

- Piston above deck

for me

Head cc + Gasket - Piston Dome - Piston above deck = CV

58 + 7.81818 - 10 - 2.49811 = 53.32007

CV + SV =

53.32007 + 505.363208 = 558.683278

Answer ÷ CV = Compression ratio

558.683278 ÷ 53.32007 = 10.477917

=

10.48:1

[Gerg_R31]

0.010" grind is 1cc on an unopened chamber

[SKiT_R31]

Compression is the winner for N/A imo; it’s like upping the boost on a boosted car.

I wouldn't have minded having the P platers laws (Tas doesn't have it) I think it'd be a bit of fun to get some sneaky power.

If I was in that position I'd go an RB25DE coupe, opt for a 2.5" mandrel exhaust, high flow cat, 2 x quality straight through centre offset fibre packed mufflers (keeping the volume down well below legal, nearly stock - no cannon, just a simple 2.5" outlet with discrete or no tip). Then I would pull the head off, get it shaved and fit a slimmer head gasket aiming to bump the compression up around 11.0-11.5:1, lightweight flywheel and HD GTST clutch and fit 255/8.5 tomeii cams & adj gears. Leave the stock air box and piping, stock heat shields and everything else in the bay looking completely standard. The last thing I would change would be the ECU, I would fit a Z32 (or stock if R32 RB25DE) nistune ecu, and spend good time tuning it, the most aggressive fuel mixture & ignition timing setting at each RPM point (without knock), also tuning leaner and equally as aggressive at part throttle.

I would be really interested to see what power you'd end up with, I would definitely expect it to match that of a factory turbo, the car would be amazing fun (esp for hills and track) response would be great, police couldn't find anything (as long as your exhaust looks factory, none of the other changes are visible, those cams are mild and wont effect your idle). On top of this, it would be an incredibly responsive daily and the economy from it would be great, even N/A's are tuned excessively rich from the factory, tuning it - even with cams should return a healthy 10-11L/100 (I get this from my NA+T with just a mild SAFC tune).

The real winners would be those with the RB25 R32's, nice and light, with the above mods should easily net more than a stock RB20DET and with that weight advantage it would be quite zippy.

I'd leave the car 4 stud, but buy turbo callipers and blank discs (and get them drilled), Auto GTST factory LSD, aftermarket suspension (as you would with a turbo anyway) some F5 R4 spring rate adj damper coilovers set at standardish height on the street (you could get away with a bit lower), aftermarket sways and finally some tame rims. It would be an amazing package imo.

Then when P plate time is over, either sell it and get a turbo OR if your attached to the chassis, just build up a turbo block with some lower compression forgies (to compensate shave, as you wouldn’t be able to NA+T this) and drop it under. The car would be an amazing base to start with as you already have all the supporting mods, and then you can just skip the stock turbo/intercooler route and go straight for FMIC and high flow/aftermarket. The only things left holding you back would probably be holding you back in your factory turbo car anyway.

[Gerg_R31]

also noticed when i ground my rb26 head the first 0.020" was a perfect 2cc then at 0-0.050" was 6cc's and 0.060" was 7.4cc

also skit_r31 a motor of any sort doesnt rely on just the compression or the cams for power it relies on everything working together

plus re reading what you posted are you having a conversation with yourself within your post?