I would want to know what failed on your car before I went too far.

However , the issues with the VR.

Pistons , the rod strength.

The stock pistons can chunk with some detonation. Factory pistons have a tendency to do this. A good aftermarket set of pistons will help minimize this, but when you make one part stronger, the next weakest part fails.

Factory rods- the loads on the rods go up with horsepower and revs. The Cobb Time Attack car just tossed a rod. It was making good power, but from what-- I am thinking--, it was probably revs related. The higher you rev, the more load you put on a rod. At stock RPM and power levels it will last 100k.

I wouldn't worry too much about the crank.

The heads are good, but anything you do to touch them , will help the air pump work more efficiently. Cams will help get air in and out.

 

I would want to know what failed on your car before I went too far.

However , the issues with the VR.

Pistons , the rod strength.

The stock pistons can chunk with some detonation. Factory pistons have a tendency to do this. A good aftermarket set of pistons will help minimize this, but when you make one part stronger, the next weakest part fails.

Factory rods- the loads on the rods go up with horsepower and revs. The Cobb Time Attack car just tossed a rod. It was making good power, but from what-- I am thinking--, it was probably revs related. The higher you rev, the more load you put on a rod. At stock RPM and power levels it will last 100k.

I wouldn't worry too much about the crank.

The heads are good, but anything you do to touch them , will help the air pump work more efficiently. Cams will help get air in and out.

actaully my engine is in total bits 2 pistons have gone 3 and 4 and the crank has took some punishement and its not that bad tbh, considering the rest of the block is mangled

so i know thats a strong part.

 

are you sure your engine didnt blow up die to knocking? couple of members here have blown engines due to knock. and there are people over 700whp that have engines still running strong. your engine blowing up doesnt substantiate that vr38 s weak. there are a lot of reasons. have you determined why your engine threw a rod?

and GL with your build!

edit: i have read a lot that stock turbos run out of breath and start blowing hot air in and also you really need to upgrade your intercooler.

anyways it really sucks to have a blown engine. GL

 

Just as Tyndago mentioned, I'd be interested in knowing what failed on your car first.

But to answer your question, if you're making anywhere over 700WHP, you should consider modding the internals. Any responsible tuner, who has studied the VR38 would advise you to do so. They are very well engineered, but they weren't build to make BIG power, Nissan focused on the response instead.

My car makes well over 700 WHP on pump, and it has ran PERFECT for 8000-9000 miles now, but I have been advised by my tuner that 700WHP is about the engines limit, so I intend on beefing up the internals soon, before something fails.

From what I have heard, its either the pistons that fail, due to detonation on poorly tuned cars, or the bottom end bearings slowly wear out because of the stress.

I imagine a well tuned car can run much longer, but VR38 has its limits and most tuners know what the limits are.

I think this topic should be discussed more, since we're seeing some BIG HP these days.

 

some good points there, which makes me think i need to upgrade my pistons and conrods..if i want 700bhp or face disaster again sooner or later..

bullo like you said at 700 yours is on limit and last thing you want is holes in the block due to weak parts..

 

Aside from Jurgen's present 700+ target, his engine that failed was barely running 160 BHP/liter, even the weakest modern pistons I've come across (EJ257) can usually take that. It had uprated intercoolers, no cats, was running sensibly rich and the ignition timing was gentle with trivial knock sums, and it failed during brief acceleration in mild temperatures. It was running 5 PSI less boost than others have gotten away with on similar spec and octane. None of these sound like the recipe for a detonation related failure, and if it was how on earth do you prevent it? You can't sensibly run less timing or richer fuelling as you'd end up with higher exhaust gas temperatures or more dilution of oil with fuel respectively. If you ran only a little less boost you'd be back at stage 1 boost levels run on stock actuators.

I've not seen any studies of individual cylinder temperatures or lambdas on the VR38, nor any documentation about fuelling asymmetries, it seems to all be speculation.

 

Aside from Jurgen's present 700+ target, his engine that failed was barely running 160 BHP/liter, even the weakest modern pistons I've come across (EJ257) can usually take that. It had uprated intercoolers, no cats, was running sensibly rich and the ignition timing was gentle with trivial knock sums, and it failed during brief acceleration in mild temperatures. It was running 5 PSI less boost than others have gotten away with on similar spec and octane. None of these sound like the recipe for a detonation related failure, and if it was how on earth do you prevent it? You can't sensibly run less timing or richer fuelling as you'd end up with higher exhaust gas temperatures or more dilution of oil with fuel respectively. If you ran only a little less boost you'd be back at stage 1 boost levels run on stock actuators.

I've not seen any studies of individual cylinder temperatures or lambdas on the VR38, nor any documentation about fuelling asymmetries, it seems to all be speculation.

Thistle, was the failure due to detonation? Or lack of lubrication?

 

How to prevent if you can't find the cause? If it had sudden detonation sufficient to do what it did, I would fear that even the best forged pistons would be able to withstand that for long, you'd need to always use higher octane fuel or E85, both of which are tricky for road cars in the UK due to availability. Water/alcohol injection is a possibility, just used for cooling and not tuned aggressively, you'd end up adding it to a brace of transmission/diff/brake coolers, does seem over the top but it is a heavy car with cooling issues.

Otherwise the main suspect areas would seem to be the oil system, pistons, rods, liners. It would be very easy to do something worse than the stock liners I think for cooling, knock, friction and scuff resistance. Who knows how this engine will go with forged pistons with these liners? It is common on a lot of engines with forged pistons to expect well short of 100000 miles before refreshing things especially if used hard.

 

just to add, i dont want yous to speculate about my engine failure to much - i know its not map related..

thistle tunes have been great and will continue to map my car..

my motor had 17000k miles on it maybe it got weak over time - been tuned since 3k miles and over 2 and half years.

(maybe 15k miles at close 600bhp is a decent return ) but i dont think they are that weak..

but the reason for thread is now my old one is out am going to take advantage by upgrading and i dont want to suffer an engine failure.

so hence the thread to see what guys do at 700 and how are they lasting..

when this motor is up and running again i dont want any heartache or expenses again.

am just hoping i can prove to nissan this oil sealent is a BAD THING.

 

just to add, i dont want yous to speculate about my engine failure to much - i know its not map related..

thistle tunes have been great and will continue to map my car..

my motor had 17000k miles on it maybe it got weak over time - been tuned since 3k miles and over 2 and half years.

(maybe 15k miles at close 600bhp is a decent return ) but i dont think they are that weak..

but the reason for thread is now my old one is out am going to take advantage by upgrading and i dont want to suffer an engine failure.

so hence the thread to see what guys do at 700 and how are they lasting..

when this motor is up and running again i dont want any heartache or expenses again.

am just hoping i can prove to nissan this oil sealent is a BAD THING.

Thistle is a genius, I am not even remotely concerned about that tune, I am just interested in knowing what could have been the cause. Wetherits Oil related or something else.

 

Hmmmm, I wonder what that 'sealant' could be.

Majority of the failures have been due to either bad tune or lack of lubrication.

 

its the sealent from the sump gasket.

 

(has the vr38 been over engineered already at 500bhp unlike the 2jz engines stock 300 easy take 800).

The VR38 is very overengineered. We're already seeing stock blocks making over twice the factory power output. The 2JZs stock internals are not as strong as you may think either. Laid next to eachother the VR38 has beefier rods and pistons. The VR38 will most definetly be more reliable long term at the 700-900HP levels then a 2JZ.

 

i have decided to go -

fully forged pistons with uprated rods and uprated crankshaft and headgaskets.

question for yous whats the deal on the plasma bore liners.....

what are tuners doing about them..

 

i have decided to go -

fully forged pistons with uprated rods and uprated crankshaft and headgaskets.

question for yous whats the deal on the plasma bore liners.....

what are tuners doing about them..

You need to contact Sharif for one at Forged Performance. His shop was building a high hp car not long ago and cylinder wall liners, (sleeves) were part of the build. Finding out what he used would be excellent advice imho.

Also, it really sounds to me as if your JDM GT-R suffered oil starvation due to the sealant all over the bloody sump pick up. Yours isn't the first to experience this iirc, and yours had to be an early build, yes?

Nevermind. I just saw in the engine thread that you found Sharif's thread about this build.

Bish

 

if anybody wants to sponsor me some parts or offer me some good deals please pm me or email me at

info at jm-imports.co.uk

it will be the first R35 GTR to be fully built. (in UK)

 

I'll sponsor you.

PM sent

 

Get new liners from underpressure! His engine died and is determined to make that engine bullet proof! they re spray them with a proven race coating. Also rods and I hear the heads can warp and gash the liner causing a failure.

Jun also coats there liners with a simular product but I'm guessing its more affordable from underpressure.

Also there are many good notes by wink from gtr.co.uk forums (search posts by user name wink. He has a wealth of data that some keep ignoring and I have expressed much prior.

 

Get new liners from underpressure! His engine died and is determined to make that engine bullet proof! they re spray them with a proven race coating. Also rods and I hear the heads can warp and gash the liner causing a failure.

Jun also coats there liners with a simular product but I'm guessing its more affordable from underpressure.

Also there are many good notes by wink from gtr.co.uk forums (search posts by user name wink. He has a wealth of data that some keep ignoring and I have expressed much prior.

thanks for info what happend to underpressure - was he running already aftermarket pistons and rods..

cheers