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Discussion Starter #21 (Edited)
or learn to drive better :popcorn:






:runaway: sorry had to be said :)
No offence taken as I'm aware they're better drivers hence why I need more powers to catch them up on the straight after they've left me behind on the corners!

My plan is either 2 or 3 steps to get the end result from where I am now with each step costing 10-15k if possible (ideally less). So turbo's and manifold setup fitted + mapped, then forge engine and finally gearbox build. That's a lot more palpable and the incremental upgrades will keep me entertained than dropping 40k in one hit and waiting impatiently until I can justify spending that much in one go.
 

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No offence taken as I'm aware they're better drivers hence why I need more powers to catch them up on the straight after they've left me behind on the corners!
I dont know how well (or bad) you drive..... in the corners is brakes and weight, thats where you make the time up. If the weathers good R888R tyres :D

How much quicker is a stage 5 car on acceleration out corners, etc? IE. own a track with the same driver?
 

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I disagree - the bhp / torque gain is up to the mapper - i get the pressure bends the rods but metal bends easier the hotter it gets
We've had stage 4's with stock turbos pushed to the extremes throwing rods and stage 5's with aftermarket turbos/intercoolers doing the same when torque goes north of 600 lbft with the stock engine, we've even had stock engines with stock power throwing rods.

If you want to run more than 600+ lbft torque with the stock engine and track or drive the car hard then either forge the engine or get a tuner warranty or it's only a matter of time.
 

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Discussion Starter #24
We've had stage 4's with stock turbos pushed to the extremes throwing rods and stage 5's with aftermarket turbos/intercoolers doing the same when torque goes north of 600 lbft with the stock engine, we've even had stock engines with stock power throwing rods.

If you want to run more than 600+ lbft torque with the stock engine and track or drive the car hard then either forge the engine or get a tuner warranty or it's only a matter of time.
Is there any data on the failure rates of tuned GTR's?

I'm assuming there are 100's if not 1000+ tuned GTR. At what failure rate does it become statistically significant?
 

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Rod failures are simply cyclic fatigue of a high stress component that was never intended to be subjected to prolonged load beyond its design limits.

Reduce charge temps and lower boost by all means but if the load applied to the conrods (which in turn provides the torque that is applied to the crank) is excessive for long enough, they will bend.

Metal is malleable , undergoes plastic deformation and has a limit to its flexural strength. That's when things go boom.
 

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True

Plus how many are driving about with bent conrods - my guess is quite a few
That's something I've often pondered (760bhp / 650lbft personally for 18 months now and circa 8k miles stock engine/box).

I tend to think that once the rod is slightly bent it can't hold on for very long before its toast as it's going to be undergoing stresses way out of it's design spec.

As a financial proposition, it really depends on how hard you can work your money. For me the money forging would be money not invested elsewhere and given I've now had 18 months without incident I'm pretty much at a point where that money has made a big enough return to pay for a new block if I encounter problems. I may not get any problems for the life of the car, it may go pop tomorrow - who knows.

One thing is for sure, if you are over stage 4 on a stock engine make sure you have enough cash set aside for a new block (£10k?).
 

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Thing is, the GTR is a superb beast of a car but your trying to keep up on with cars that are currently at the top of their game. The 488 and 675 are simply superb engineering artworks that will blow the GTR out of the water on spirited A roads.

I honestly believe your quest for more BHP on OE internals and OE Gearbox would be a bad choice. I've seen well set up Stage 1 cars eat a new GT3 RS on a track and that's 580bhp but has a well set up car on KW coilovers, Cup's and Alcon BBK.

Bet its fun driving with those beasts though!!
 

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The 488 and 675 are simply superb engineering artworks that will blow the GTR out of the water on spirited A roads.
I don't agree with that, if we're talking stock cars then the GTR is within a whisker of them on A roads. If anything it's going to lose out to them in a drag race due to bhp and weight.

I think realistically you would need to get the power weight close to them to make it fair, at which point I don't think they'd put any distance on a GTR.

In fact I think the GTR would be much easier to drive at close to the limit without fear of ending up in a tree due to to the 4WD.
 

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Discussion Starter #32
I don't agree with that, if we're talking stock cars then the GTR is within a whisker of them on A roads. If anything it's going to lose out to them in a drag race due to bhp and weight.

I think realistically you would need to get the power weight close to them to make it fair, at which point I don't think they'd put any distance on a GTR.

In fact I think the GTR would be much easier to drive at close to the limit without fear of ending up in a tree due to to the 4WD.
+1

AFAIK going fast isn't witchcraft, especially to overcome a delta on the straight it's power to weight ratio. The chap with the 675LT races it in a road car series and takes liberties on the road which I couldn't do if I had a £400k car.

I think forging the engine is prudent but at this point the "certainty" of sending a rod through the block with upgraded turbos and a safe tune is anecdotal. Even from my 4.25 a EFR turbo car seems to spool faster and have a bit more punch which would improve the driving experience IMO until I can justify funding a forged engine.
 

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+1

AFAIK going fast isn't witchcraft, especially to overcome a delta on the straight it's power to weight ratio. The chap with the 675LT races it in a road car series and takes liberties on the road which I couldn't do if I had a £400k car.

I think forging the engine is prudent but at this point the "certainty" of sending a rod through the block with upgraded turbos and a safe tune is anecdotal. Even from my 4.25 a EFR turbo car seems to spool faster and have a bit more punch which would improve the driving experience IMO until I can justify funding a forged engine.
I would personally be tempted to stick a pair of the Linney IHI900 turbos (paulmc used them on his DIY 800bhp). They're only £2500 + VAT and good for 800+ on 99 RON.

The litchfield EFR's are a work of art, but I don't see the extra £5k worth in them.

It also raises the option of sticking in the IHI900's and forging for the same price as the Litchfield EFR's.
 

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I would personally be tempted to stick a pair of the Linney IHI900 turbos (paulmc used them on his DIY 800bhp). They're only £2500 + VAT and good for 800+ on 99 RON.

The litchfield EFR's are a work of art, but I don't see the extra £5k worth in them.

It also raises the option of sticking in the IHI900's and forging for the same price as the Litchfield EFR's.
But would get the spool like the EFRs? Thats where the r&d has gone into with turbos & manifolds.
 

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Discussion Starter #35
But would get the spool like the EFRs? Thats where the r&d has gone into with turbos & manifolds.
From what I understand for response there isn't anything better than the EFR's for this platform.

How much difference does the manifold make in the real world? I see Linney sells the EFR 6758 without the fancy manifolds for considerably less.
 

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Sure the Litchfield EFR's are the holy grail of spool and power, but let's not beat around the bush here - your looking at £6k incl VAT on top of the Linney IHI's and £3800 on top of the Linney EFR's.

For a few hundred RPM difference in spool I don't think it stands up financially.

Money no object then of course you get the Litchfield EFR's, and I fully understand the R&D cost in them, you cannot allow that to muddy the actual result and how perceptible the difference is.

You could do the IHI's and forge for the cost of the Litchfield kit. That's a safe step and if you then decide a year down the line that you need that 200-500rpm spool difference you can swap the turbo's then with a safe engine in the mean time that you won't be afraid to crank right up.

A forged engine with the IHI's should push out 850bhp comfortably.

850bhp is what you need to at parity with the Mclaren on power/weight - that's a very scary thought really.
 

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I had always wanted to do turbos, then the lump then the box. Each time releasing the turbos that bit more to feel the benefit of strengthening of the other components. As it seems to be panning out I am into the box at the moment which sucks as there will be no additional performance gain.

Doing turbos on their own, provided you pick sensible turbos - isn't neccesarily a bad idea on OEM rods. You can run 600/625lbft in the mid range but without the significant drop off in torque towards the red line which will liberate more power.

I agree with Terrys theory about the stock turbos running hot at stage 4 levels and as such a better cooler and less restrictive turbos could themselves aid reliability despite the extra top end power.

With all that said though, I too have seen the flurry of rod failures of late. Is it just the nature of the battalion facebook format and lack of user 'history' that promotes a nice open community - or genuinely more failures of late? I don't know, but it has certainly given me some food for thought and a renewed desire to forge my engine.
 

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We are seeing rod failures being reported more simply because of two factors. Many cars are 7 years old and have been running much power than stock for significant time now. Also there is more dissemination of information through social media.

As an example my 09 has 60k on it and has run stage 3 for 1 year and stage 4 for the last 5 years.

My clutch basket B went on Saturday (tbc today) and I'm not surprised. It'll get an upgraded clutch pack asap.

The risk of mechanical failure increases as a factor of load and time. We will see more failures and I do believe the number is vastly under reported for many reasons. The most likely is that folks don't want to publicise them as it may affect resale.
 

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If mine breaks it will be all over the forum i dont care about the resale ( if its fixed i dont see a problem ) - my idea of a good forum is to learn about the cars good and bad

What sort of hp/tq can the oem clutch hold ? also what are the uprated clutches like to live with
 

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I upgraded the baskets when recently having a shift upgrade done at AC Speedtech, they also fit a Linney clutches in the fix.

They are definitely harsher that OE due to the different friction materials I guess and at Low speed and rpm (when you wish the car would select 1st but it stays in 2nd) you can hear them chatter in the basket more.

I'm going In tomorrow to have the shift points changed at lower rpm and for Andy to just refine the gearbox and engine Map for me.
 
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