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How to turbo your N/A


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  • 2 months later...
So you want to get more bang for your buck and whack a turbo on your skyline….well the following are things I've found out on this ever talked about path.

First thing…get yourself an N/A Skyline, if you're reading this then you too have made this fatal mistake ;)

The second thing you should do is get yourself some sort of engine management…one that can adjust airflow maps and injection maps…to a lesser extent timing.

I used the GReddy e-manage as my car is auto and I didn't have a choice in the matter, even if it had been manual I still think I would have got it, due to the ease of installation and programming.

Other options available are getting the factory ECU…but I'm not sure if it would work as it would not have all the signals coming in that the stock turbo engine would put out.

Next step get the essential engine parts…you WILL need the following.

Turbo (of course) preferably with water an oil lines

Exhaust manifold

Dump-pipe & Front pipe

Fuel Pump (GTS-t one or better, plenty of high-flowing cheap ones out there, walbro etc)

Injectors (stock GTS-t ones or better)

Intercooler and piping (stock or custom)

Alloy cross-pipe with BOV (once again custom jobby will suffice)

All of the above can be the factory items or replacement parts for the turbo model, not a bad idea in the case of the intercooler…as with your 10:1 compression keeping things from going boom is a good idea :D

I used a series 1 R33 turbo, ceramic exhaust wheel jobby…you don't really need anything more substantial as you can't go too far past 7psi and the ceramic turbo should last indefinitely at this boost.

Almost all of these items went straight into my R34 with only the exhaust requiring an extra section welded in to make it fit.

The oil & water lines were modified and extended with stainless steel braided hose. The water supply was taken from the heater lines…the oil feed had to be taken from near the filter and the return is via a tap into the block..

Standard, the waste gate on the turbo will open at around 5psi..to get 7psi you'll require either a bleed valve…or the factory solenoid powered by a constant 12v and put inline with the actuator hose on the turbo.

So now you've got everything bolted to your engine you need to get a complete dyno tune, where your ignition will most likely be retarded by about 5 degrees just to keep things safe. Once completed you now got a very different car from when you began…it's actually got some decent power :cool:

Of course none of this would have been possible without Robin at *perFOURmance Motorsports*

The final tune on my car is Thursday, so I'll have dyno charts and pictures available on Friday.

Anyone wanting specifics PM for more details.

So let's see who's next!

Dan

Thanks for the info. just wondering did you have to upgrade the gearbox too? as i have a r34 gtv and will be turboing the car real soon but not sure whether the gearbox will also need to be changed to handle the extra power.

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Yeah, R33 GTS4 boxes are the same as the R32 GTR box but with slightly different gear ratio's.

N/A boxes are more like RB20DET spec, they'l cope fine with gentle shifts and limited clutch drops (pending grip) but the power will eventually wear them out and make them sing. Hard shifting is likely to smash a selector and damage teeth, and high power high grip/load clutch drops will just shatter the box into multiple peices.

I've gone through one in my R31 (RB30e+t), the synchro's were always knackered and it started to sing badly after a couple years - boosted it in reverse once and chipped a tooth off (so reverse used to click) once i got a replacement box (reco RB20DET) took a couple clutch drops and flatshifts before i smashed the box to peices. I've been much gentler on the new box and have had no issues.

Edited by SKiT_R31
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R34 GT-Vs and maybe all R34's i think have the RB20DET box, look it up on wikipedia etc.

Is it worth turbing an N/A?

Does it make your car any decent power? haha because faaaaaarkk I'm getting sick of having no power, should i sell my car and get a 350z or just turb the 34?

i don't need to buy bigger brakes etc, its just the clutch and gearbox that i might need to sort out.

Edited by R34 -_-
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I am assuming about $6000 to turbo the NA and replace the NA box with a RB25DET box and new clutch. anyone have any ideas about the total cost?

Cost me easy under $1500 total to turbo my R33. Inc injectors, ecu, R33 cooler piping & crossover pipe, R34 SMIC, R34 turbo, R33 factory dump pipe, braided oil feed line, custom drain, inc misc fittings/nuts/bolts/gaskets.

Did all the work my self piece of piss over a weekend.

Ran fine on stock ignition timing on stock boost, with more power than a factory RB25DET and spooling at <2000rpm. Only issue was I couldn’t really up the boost without winding the timing back, but I like my response so that wasn’t an option. 98ron is a must have, engine coolant temperatures are fine (with N/A single core radiator) with water lined hooked up on turbo (MUST). Oil does get quite hot and mineral oil thins out fast, so I recommend a good quality fully synthetic.

I also changed my spark plugs to a colder heat rating and stock turbo gap (BCPR7ES), and i already had both splitfires and a HD GTR clutch (which you may have to factor into price).

For more power i added pre throttle body water + meth injection (50/50), cost $300 for everything, this allowed to safely up my boost up to around 9-10psi (I didn’t want an FMIC, with one you could run the same boost without the meth) and made 164kW at all four wheels on 9psi (10psi or higher was giving me boost spikes, not pinging but causing R&R after spike). As per any stock RB25, above 5000rpm was excessively rich, in the high 10's low 11's A/F ratio (not a problem)

But or some reason between ~ 3000 and 3500rpm i had a massive lean spike (~15:1), as if the car was rpm/tps mapped and not airflow mapped. As the more boost it ran, the leaner, the less - the richer. Stock boost had a perfect 12.5:1 AF/R. $250 later i fitted an SAFC (AFC neo) but no matter how much fuel i tried to give it, at WOT between those rpm's, fuel mixtures didn’t change (but did on light throttle).

After that, using my own wideband data logger I tuned the rest of the WOT maps to ~13:1 down low, 12.5:1 mid trailing to 12:1 in the top end and returned the car to stock boost (makes a lot more power than it did previously on stock boost, just from fuel adjustment).

A normal person would probably go after market management at this point, another option would be an electronic boost controller like an AVCR to increase boost after the lean spike (i think this lean spike is isolated to my car, nfi why).

My next plan is to get the water+meth on again, this time pre-turbo, using multiple ultra fine mist/fog spray's (to avoid damaging the turbo), along with a dual stage boost controller activating high boost (9-10psi) at the 4500rpm using the ecu's factory earth switch (normally used for the factory boost controller) with the water+meth injection starting just above stock boost (stock boost is ~ 6.5psi, so I’d set it to 7.5psi).

The trick with using water spray pre-turbo, is it is much more efficient at cooling as it cools during compression (when the boost pressure it much hotter and higher than what hits the pipes) which increases turbo efficiency and as air cools as it decompresses, is much more efficient at cooling (with the high humidity boost then being more knock resistant within the engine).

This plus my tune (Fuel maps, plus i have raised ign timing to 20 degree's), I am hoping for >180kW atw (250whp is my goal).

Sorry for rambling slightly off topic, but it might be interesting for N/A+T goer's.

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That didn’t really have much to do with the current topic (gearboxes). But, <200kW treat it with respect - the gearbox will handle without any problems. To get more than 200kW out of a factory N/A your going to want to spend big bicky's on a decent turbo, aftermarket management, FMIC, a clutch to suit, etc - so investing in a turbo gbox shouldn’t really be much of a concern (just like the RB20DET boys looking to make big figures)

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But where's the fun in that! :P

Seriously though, it really is the best option. The car will be much more reliable, already setup with drivetrain/suspension/brakes and can make the power you’re probably after with only basic mods, all day everyday (and you won’t have to think about it again).

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^ in a nutshell. i did the next best thing and transplanted a GTST motor and running gear (with a few extra goodies) into my GTS25. only because i was happy with the car and how clean it was. still need to do the brake upgrade but all in time

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  • 3 months later...
  • 2 weeks later...

I am getting info on turbo for a N/A Rb25DE in a Stagea. Stock injectors are 260, and I want to fit DET injectors which are 360/370. Will the larger ones fit the DE Rail?. I have fuel pump and coil packs and ecu from a DET.

This info is not on Stagea Forum as all Stageas that came in under SEVS are all turbo. The one I got for my P Plater son was a private import.

Are there any other N/A Stagea owners out there? If so would like to hear from you.

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