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[sajid_arif]

Hi. I am a proud owner of a R34 skyline 1998. turbo manual. I recently bought the car and was advised by the previous owner that the following modification was done to the car:

Front mount Intercooler with custom piping

3 inch turbo back exhaust

Boxed pod filter.

GFB boost controller (currently running 12 psi )

The owner advised me that the car is pushing close to 230rwkw

Everything else is stock

Now the car is running fine when it comes to performance but its not so great on fuel

I would like to do the following mods but i am unaware of the advantages i will get

Can some one please explain what the advantage of having the following done could be:

1.Bigger injectors( preferably nismo 550 or higher)

2.Walbro fuel pump

3.Coil packs(spitfire coil packs)

4.Bigger turbo( what would be preferable??????)

5.Plenum intake manifold

Any help will be appreciated? thanks?

[Galois]

Searching will give you all the answers my friend. But I'll tell you all I know anyway.

With stock turbo, unless it's highflowed, I very much doubt you're getting anything over 210rwkw, and even that seems rare and unlikely based on the dyno thread in the forced induction section (go have a look, people list their mods and their dyno results).

Also why do you want to do mods if you don't know what they'll do?

You upgrade duel pump and injectors when the stock ones can't shift the fuel your engine can consume. This usually comes with a bigger turbo. Bigger turbo usually means more lag and 2-3k out of pocket. If I were you and was after more power I'd get mine high flowed then tuned.

I think bosch is the preferred fuel pump for skylines, an awful lot easier to fit as it just bolts right in, though do a search to confirm that.

Plenums are useful for some gains if you have cash to throw at the engine and you're doing an engine build. You have to ask yourself, to you think upgrading the stock plenum is the best way of getting more power at this stage of modification?

On coilpacks, I went yellow jackets. They're as good as splitfires, $200 cheaper and have a 2 year warranty. The only reason I can find that splitfires are still so popular is that they've been around much longer (though yellow jackets have been around for years now).

Your factory coilpacks will die eventually, it's up to you whether you wait for a misfire to replace the coilpacks.

Read this http://www.skylinesaustralia.com/forums/topic/282082-nissan-skyline-r34-gtt-modificationtuning-guide/ then have a good search. This is a great forum, all the info people may need is already on here.

[jrm]

Hi. I am a proud owner of a R34 skyline 1998. turbo manual. I recently bought the car and was advised by the previous owner that the following modification was done to the car:

• Front mount Intercooler with custom piping
  
• 3 inch turbo back exhaust
  
• Boxed pod filter.
  
• GFB boost controller (currently running 12 psi )
  

Everything else is stock

The owner advised me that the car is pushing close to 230rwkw

Without a dyno sheet to back this up (and even then, those can be faked with dodgy ramp rates), I wouldn't believe a word. You haven't listed aftermarket tuning for starters, which means you're going to be pushing maybe 190rwkw at most. Even with tuning (nistune, etc), 210rwkw (as the last post indicates) is about the limit of the factory turbo and would be about right for 12psi. (You'll see this backed up in the RB25 dyno results thread).

Now the car is running fine when it comes to performance but its not so great on fuel

This agrees with the lack of an aftermarket ECU - they will chew fuel badly on 12psi without tuning, and really puts into question the claimed 230rwkw.

I would like to do the following mods but i am unaware of the advantages i will get

Can some one please explain what the advantage of having the following done could be:

1. Bigger injectors( preferably nismo 550 or higher)
   
2. Walbro fuel pump
   
3. Coil packs(spitfire coil packs)
   
4. Bigger turbo( what would be preferable??????)
   
5. Plenum intake manifold
   

The nismo 550 won't fit your RB25-NEO motor that the R34 have. You'd need to go the nismo 480cc's. If you went this option, be aware that this will limit future power options up to about 300rwkw - not really an issue for most.

If you're fuel pump is on the way out (and given the car is over 10 years old, it wouldn't be a surprise), then replacing the fuel pump is a good bet. You'll also need the increased flow if you start fitting larger injectors, turbos, etc. I went a nismo fuel pump myself, but there are plenty of options. I would suggest going something that is direct drop in and doesn't require modifications, special wiring, etc.

Coil packs - only if the current ones are damaged or misfiring. Whilst they're over 10 years old, if they've been regularly sprayed with silicon spray (as per the service manual), etc - it's likely they're fine. If you're starting to have misfiring, then there are plenty of options, including Splitfire, Yellow Jacket, etc. Personally I went Yellow Jacket as insurance as I increase power though my original OEM coil packs are still perfect (on the shelf in the garage..)

Bigger turbo really comes down to how legal you want to be, your power goals, etc. (Legality and how likely you're going to get caught for upgrading the turbo largely comes down to what state you're in - SA and Vic are probably the worst). You could go to anything from a simple highflow to 3076, etc - it ultimately depends on your power goals.

I really wouldn't bother with any sort of aftermarket plenum unless you have serious power-goals in mind. The factory plenum is fine.

Really, to save money, and ensure you do things once, and do them right I would suggest you get a plan on what you want to achieve, your power levels, and work out what parts, etc you need to achieve that. There is a lot of information available on these forums, and the dyno thread is there with lists of modifications showing what other people have tried. Don't forget to use the search function.