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Discussion Starter #1 (Edited)
Hi,

I have stage 4 (I think!) atm, mapped by Ben @ GTC
With his intakes
1000cc injectors
decat downpipes
decat ypipe






Looking for that next stage up, but as all tuners go slightly different ways about thing and having their own interpretations of stages 4/5/6 I'm finding it a little tricky to know what to do.

Basically I want some more ponies for without spending a fortune (if that is do-able)

1. What is the safe limit of the standard internals?

2. Is is very expensive to upgrade internals?
If yes to question 2, then I'm looking to achieve the number given to question 1 :p

If I am right in thinking the standard internals upgrade is many thousand £, and that the limit of the standard internals is around 750?? Then I am not looking for a huge upgrade in turbo.

So:

3. Do I buy a upgraded turbo set up, or get standard ones 'tuned up'?

Whifbitz do a 730bhp stock turbo tune up for £2,500 which seems a lot? Unless someone comes and tells me it takes many days to complete, and lots of hardware and specialist tools are required? Then it will certainly not be so expensive.

They quote:
"The turbos are modified to produce the extra power with a new larger 60mm IHI compressor wheel along with a 360 degree thrust motorsport bearing."

Maybe they are making it sound easier and quicker than it is.


Are there other companies that do this?

4. What other mods will I need to get the the safe limit of my internals/ 730bhp whifbits upgrade.

I'm guessing fuel pumps? this is ok as they're cheap?

Intercooler? Full exhaust? These are many 1000£ as you all know so if I don't do them, what power can I expect? Not the 730 whifbitz quote?


The car is a daily drive for me, It will not be going near a track and does not get crazy hard use.

Thanks in anticipation!
 

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Have a good look on the Litchfield Imports website.

There are options, costs and figures for what standard engines can take including cost of upgrading pistons, rods etc...

Put simply, there is a lot of info there and most importantly they are open enough to put all the pricing info on there too.
 

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Hi mate, my car is at the same stage as yours and there is no real easy way to sugar coat this but any next step you do is going to cost.... and cost big.

Really you need to upgrade your Rods.... so straight away you have and engine build... £5k ish
Turbos... £2500 sounds cheap... I have never heard less than £8k from SVM
Intercoolers... £2000 ish
Gearbox circlips and strengthening.... £5k ish
Uprated clutch and basket.... £3k I think... possibly cheaper.
then you have brakes to think about call it better discs and pads £1500...
remapping.... £600...800 ish

anyway you look at it... I cant see you safely going further without spending £15k... Amar at SVM told me that to go any further was £18k...

at the moment this is why I am sticking with 650R.

I just cannot justify the £30k+ I would need to earn to cover it.

Get some lovely suspension parts and be happy... you will never recover these costs.
 

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Discussion Starter #4
Have a good look on the Litchfield Imports website.

There are options, costs and figures for what standard engines can take including cost of upgrading pistons, rods etc...

Put simply, there is a lot of info there and most importantly they are open enough to put all the pricing info on there too.

It's using their sites, and other tuners I've been able to make the assumptions listed above, just wanted somebody to confirm them.

Im basically at Litchfieds stage 4 but with dps rather than ypipe back

They quote turbos for stage 4.5 700bhp
and for stage 5 750bhp, and no mention of internals work.

They do a stage 5+ which is where the internals start
Litchfield - Nissan GTR Engines - Litchfield Motors
Which is 775bhp- 800bhp, this internal job costs £4.3k


Sooooo, I'm happy with 750 bhp as i don't want to pay £4.3l for 25bhp, maybe 50.


Which turbo shall I get for the 750 mark, any recommendations?
Or should I be looking at modifying my standard ones? Is what whifbitz do (730) the highest they can go? Or could I get my standard turbos modified to the limit of the engines standard internals of 750bhp? Thanks!
 

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Discussion Starter #5
Hi mate, my car is at the same stage as yours and there is no real easy way to sugar coat this but any next step you do is going to cost.... and cost big.

Really you need to upgrade your Rods.... so straight away you have and engine build... £5k ish
Turbos... £2500 sounds cheap... I have never heard less than £8k from SVM
Intercoolers... £2000 ish
Gearbox circlips and strengthening.... £5k ish
Uprated clutch and basket.... £3k I think... possibly cheaper.
then you have brakes to think about call it better discs and pads £1500...
remapping.... £600...800 ish

anyway you look at it... I cant see you safely going further without spending £15k... Amar at SVM told me that to go any further was £18k...

at the moment this is why I am sticking with 650R.

I just cannot justify the £30k+ I would need to earn to cover it.

Get some lovely suspension parts and be happy... you will never recover these costs.
Internals upgrade I think I can rule out then, so looking to get 730- 750bhp (ish)

Had the gearbox clips done mate,

Got new pads and discs

I'm only looking to go to 730 - 750bhp, not many change the clutches for this do they?

Yeah for new turbos 2.5k sounds good, but they are only supplying tuned up owm turbos and you have to send yours back to them, so 2.5k is just for their labour and the couple of bits that go into them
 

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Your next step is turbos, 750-800hp but the tuner needs to cap the torque to keep your rods inside the block.

AC Speedtech have a couple of options from £2500 - £5000 using VF34 or GT28 cores

GTC and Litchfields can both do EFR6758's (would be my choice)

Litchfields, AC Speedtech & GTC are your best options.

After turbos or to use the full potential of your new turbos you need internals and big ££££

No need to be paying GTR tax I.e. £9k for stock frame turbos.
 

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Discussion Starter #8
Your next step is turbos, 750-800hp but the tuner needs to cap the torque to keep your rods inside the block.

AC Speedtech have a couple of options from £2500 - £5000 using VF34 or GT28 cores

GTC and Litchfields can both do EFR6758's (would be my choice)

Litchfields, AC Speedtech & GTC are your best options.

After turbos or to use the full potential of your new turbos you need internals and big ££££

No need to be paying GTR tax I.e. £9k for stock frame turbos.
Thanks!

My car is 660lbs/ft atm, somebody said it shouldn't be over 600 really?

Any idea on price for what you recommend, the EFR6758's? I know I wont be milking them properly without being able to turn them up with forged internals, but thats just crazy money and if i can get 700-750bhp that'll be awesome :)
 

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660 lbft!!!

That sounds a bit high! 600 give or take is about max for the stock internals I thoughts
 

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Thanks!

My car is 660lbs/ft atm, somebody said it shouldn't be over 600 really?

Any idea on price for what you recommend, the EFR6758's? I know I wont be milking them properly without being able to turn them up with forged internals, but thats just crazy money and if i can get 700-750bhp that'll be awesome :)
If your torque figure is genuinely at 660 ft/lbs, and I don't disbelieve you, you are in danger of bending the rods.

HP is not the killer, it's the torque. You can, as others have said, get 730 ish BHP with torque capped around 620 ft/lbs and stick with standard internals.

My question is though, do you really need that much more power? Is it really worth spending that sort of money? Mine is only Stage 2 but I find it hard to believe I could use more power on the public road.

Track use yes but road use, I'm not sure.

Just MHO of course.
 

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I've been running Stage 4.5 from Litchfield for a year and a half now and still love it!
It's been dynoed at 717hp and 620lb.ft and has been completely reliable engine-wise.
I did manage to break the AWD clutch housing, but that was more down to 35k miles of wear and tear rather than the increase to 720hp.

Iain is very careful with his tuning to make sure your standard rods are kept within the safe torque level.

This actually makes for a very progressive, linear power delivery which makes the power more usable than a huge thump of low-end torque which breaks traction too easily.

I have to say though that throttle response and spool is still excellent, very sharp.

If I had unlimited funds, I would go for a Litchfield Sport engine and 850hp (any more literally becomes unusable on a race circuit which is my favourite stomping ground), but I don't, so quite happy with Stage 4.5.

It's the furthest you can go without spending silly money IMO.
 

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Thanks!

My car is 660lbs/ft atm, somebody said it shouldn't be over 600 really?

Any idea on price for what you recommend, the EFR6758's? I know I wont be milking them properly without being able to turn them up with forged internals, but thats just crazy money and if i can get 700-750bhp that'll be awesome :)


Oooh that's a bit high, I believe you need to be around 600-620 fit lbs max to be safe.

It would be best to ask the tuners, I believe they are under £5k but then you have fitting. The VF34 cored ones AC Speedtech are much cheaper but max out around 750hp. I think if I'm going to be spending £5k on turbos I would like some head room for later :)
 

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Discussion Starter #13
Martyn from a SE tuning company who is well known for GTRs was down near me doing tuning






and he said it was a rod bending figure, Ben @ GTC said it was okay when questioned..



It was only on his stage 4 base map when it was rolled. So hopefully more hp, less torque now, I'll see soon as going on again
 

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Alloy is selling his SVM stage 2 turbos, he makes around 710-720 I believe on pump fuel and standard internals.

Personally if your engine is out and your changing turbos you might as well build the engine even if it's just a rod upgrade...
 

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On the stock turbos, if you run a max of about 1.35/1.4 bar, that will give you a genuine 630-650ftlb on stock engine and pump gas. You can datalog the calculated torque in the ecu which can be more consistent than differing dyno's. I've run this boost level for 5 years and never had an issue on any of the cars, road or track use.

Turbo options... VF34 based options are a lot cheaper than any of the garrett or borg warner options due to the cores. But even with the most adventurous of machining and wheel trickery, the VF34 options all top out around 700-750hp mark and thats run to the limit.

Garrett/BW (EFR)/HTA (FP) based variants can be made to push much more power and easily dialled down to usable power on stock internals by limiting torque to around 630-650ftlb (ACX2/Litchfield stage 4) levels.

The latest HTA wheeled option from Owen Developments is a great option on a stock motor for 730-750hp (torque limited) but has headroom for around 850 hp in the future too. I'm sure JCR will chime in when they get theirs back soon too. It is at (limited) 1.2bar at around 3600-3800rpm giving 630ftlb then ramping it up from 4400rpm to 1.4 bar at redline with 740hp.
Transient boost is virtually instant, the power delivery is exceptionally smooth and just absolutely effortless.
I am very very impressed with them and one of the best options around. Price wise... around the 5K mark for the turbos plus fitting, fuel pumps and mapping.

The BW (EFR) options are excellent, but work out a little pricier and there's also the option of an aftermarket cast manifold to get the best from them and if big power is wanted. Also bumping the price up a chunk.

I'm having the latest version of my own VF34 based turbos delivered next week, the target is:
(Limited) 630-650ftlb with (a minimum) 700hp for the most accessible price. They will be running the Turbosmart ITG actuators for maximum control and response. Of course will be able to run on stock actuators if needed.
Looking forward to trying them out!

Personally, and I think other guys with uprated turbos fitted will agree, going this step is maybe the biggest improvements to the car (power wise) you can do. It removes the snappy nature of the factory units making the car much more predictable, and the constant smooth power delivery all the way to the redline instead of the wedge of power/torque midrange is awesome.

I will be very interested to try these new VF34 based units on a car with stock downpipes before going full decatted. 650ftlb/700hp retaining road legality and sensible noise levels will be a great combination at sensible prices as well.
...Just the temptation for the extra headroom and effortless power delivery with the Owen Developments units is so tempting! Choices choices!
 

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Power levels are all well and good, what I'm really interested in is something that will give a linear power curve rather than the stage 4 one which is more like a rally car. I don't want to touch the internals, nor risk things and I don't want any additional lag/spool.

The GTR does a good job of pretending to be not turbocharged but dumps torque on you in huge globs in stage 4 guise, making progress in imperfect conditions a bit tricky.

I think up to 750bhp and 600lb/ft, and a flattish torque curve for a straightish power curve is what I'd be interested in.

Something based on the stock cores and manifolds makes sense - it's much cheaper for a start.
 

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EFR 6258 in stock housings. My turbos - remain the best "small" turbo experience I've driven on a GT-R.
I'm not talking to you, splitter!!!! :)

I would have known this had you actually sold me your turbos rather than selling your whole car....

Sure you did it on purpose :D :D :D
 

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Power levels are all well and good, what I'm really interested in is something that will give a linear power curve rather than the stage 4 one which is more like a rally car. I don't want to touch the internals, nor risk things and I don't want any additional lag/spool.

The GTR does a good job of pretending to be not turbocharged but dumps torque on you in huge globs in stage 4 guise, making progress in imperfect conditions a bit tricky..
That's exactly why after my stage 4 I stuck at stage 2 on the MY11.
 

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Yep - but you can get round a lot of that just by turning the boost down. To be fair, you could map it so it was more linear, but it would be slower as it just runs out of breath at the top.

Stage 4.5 of some description is the answer and will give the car another dimension again. That's what I like about the GTR, you can't really get bored of it.
 
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