My Sti has gone into the dealership today for an oil consumption test.
Will keep you posted.

 

id say id get pistons rods studs done etc if your were looking at 400 upwards, just not worth the gamble.

Ive spoken to 2 of the builders on here and both advise that if your going upwards from 300 you really should be looking at changing things to be safe.

Not to say that it wont mind, it will have a max I presume, but as it blows up normally id get it forged :P

 

i got told pistons are **** so remap and thats max, rods are ok ish so 400 max, above 400 do the lot basicly.

 

2.5 sti rods are good for 450max so if thats pretty much the block and liners limit if reasonable mileage is expected as suggested, what the point in paying for rods. That was the point to my question.
Has anyone heard of a newage throwing a rod? I have heard of classics breaking rod bolts but not read of any newage suffering rod issues.

 

from what i was told they should be ok at 450, but its a 'should' not a ok.hence not going over 400 with them, so in my case didn't want the risk.

the other thing of course is if you replacing the pistons etc is ut realy worth not doing them?

 

Hence why i asked the question.
That's put it another way. Would you change the rods at great expense for rods that's performance greatly exceed that of the block casting and cylinder liners. given that the standard rods have about the same limit as the block and liners?
It was suggested by API that the block and liners have a limit of 475bhp if your wanting more than 20k mileage out of the engine. So if you want the car as a daily driver and or want longevity from the engine 400-450 max would be the limit. The block "should" be ok at that power as "should" the rods.

Maybe i'm way out of line saying this but it sometimes seems paranoia is very good for business. That statement is in noway aimed at anyone in particular.

 

well some folks say the blocks good for 500+ but others don't. i wouldn'r run over 400 in the standard rods

 

You can change the pistons without splitting the block, so unless you are replacing the bearings etc. why would you.

 

You should never put new pistons of a different make & material into a bore of a piston of different make & material, they should always be honed to fit, its not uncommon to have slightly different size pistons in the same box, so to go from one manufacturer to another without size & material differences is a recipe for failure.

This is what a few dealers have done for customers, then wonder why the engine sounds like a machine gun on idle.

 

I'll second that. "Drop ins" are a no no.
Fix it once, fix it right.

 

Just playing devil's advocate as there are a number of people out there offering this "service/solution"

 

lol, theres so many 'tuners' (i use the word loosly) who are clueless out there.

 

Out of interest, if the 2.5 is only really safe at 400-450 max then why do engine builders encourage owners to pay an extra £500+ on rods when the standard sti rods are good for that?[/QUOTE]

I am not sure any of us tuners have hard and fast data on how far you can push the standard rods and / or big end bolts. We have seen the bolts as the weak link and used ARP on occasions.

As for the rods themselves, can you imagine the flak we'd get if we told a customer that his rods would be fine at 450 hp and one broke. I, and other tuners, avoid the possibility of a warranty claim by negligence, by not advising the customer correctly.

So we give them the option and make sure their choice is in writing, as memories tend to get selective when something has gone wrong and an avoidable breakage occurs.

Budget comes into it too of course, but by the time most proper builds are done and in the car and working there is little change from best part of £10,000. Saving £450.00 by fitting dubious rods is not part of the plan at that level of cost.

David

 

I am not sure any of us tuners have hard and fast data on how far you can push the standard rods and / or big end bolts. We have seen the bolts as the weak link and used ARP on occasions.

As for the rods themselves, can you imagine the flak we'd get if we told a customer that his rods would be fine at 450 hp and one broke. I, and other tuners, avoid the possibility of a warranty claim by negligence, by not advising the customer correctly.

So we give them the option and make sure their choice is in writing, as memories tend to get selective when something has gone wrong and an avoidable breakage occurs.

Budget comes into it too of course, but by the time most proper builds are done and in the car and working there is little change from best part of £10,000. Saving £450.00 by fitting dubious rods is not part of the plan at that level of cost.

David[/quote]
Fair enough mate. I suppose if after an engine built a rod breaks it falls back to the builder but if the liners / block fails its down to subaru's lack of over engineering. My point was just, why over engineer in one area if its still under engineered in another. If the liners / block are as weak as you say then its quite possible fitting things like H beam rods would give a false sense of security .
I'm not having a pop at you mate. far from it. i respect you and the work you do. I'm just trying to have a realistic debate on these engines potential when forged. Have you seen any 2.5 sti broken rods? From what i understand its revs that kill rods due to velocity of piston weight stretching the rod or rod bolts rather than power . The 2.5 only revs to 7k and max power/ torque made way before the red line.

 

Quote
Fair enough mate. I suppose if after an engine built a rod breaks it falls back to the builder but if the liners / block fails its down to subaru's lack of over engineering. My point was just, why over engineer in one area if its still under engineered in another. If the liners / block are as weak as you say then its quite possible fitting things like H beam rods would give a false sense of security .
I'm not having a pop at you mate. far from it. i respect you and the work you do. I'm just trying to have a realistic debate on these engines potential when forged. Have you seen any 2.5 sti broken rods? From what i understand its revs that kill rods due to velocity of piston weight stretching the rod or rod bolts rather than power . The 2.5 only revs to 7k and max power/ torque made way before the red line.[/QUOTE]


No worries, I know you're not having a dig. The problem is that doing a 2.5 'properly ' is a complex thing to do, because of all the potential failures that you can stumble upon.

5-6-7 years back a 2.5 was all the rage and we stood back and watched and listened. Not convinced in any way that it was right for everyone. True enough, 'we' all discovered that on anything pre 96 it had all sorts of running issues. I believe due to incompatibility of bore size to combustion chamber shape.

Once others had found out to their cost that things were not cut and dried, we found that it would work on later - 97 on - heads and started doing a few. Not so much developed as found where the cut off between not working correctly and working.. Vers 3 heads onwards seemed to be the point.

Elsewhere, many short motors from the USA had been fitted with standard pistons and as soon as more than 1.35 bar was put in them - well you know the rest. That started another search for reliability.

The 2.5 does not like to rev and that is down to the physical bore stroke ratio. The engine is too ' oversquare ' and that is never good. So the 2.1 has become 'fashionable ', as its dimensions are much better suited to revving. Ditto the 2.33. BUT if you want decent, lazy, power, and many do, a 2.5 is ideal and for certain jobs it is absolutely the right answer. Restrict it to an ignition soft cut at 7000 and a full ignition cut at 7200 and it'll stay together.

I agree though, fitting heavy duty components in such an inherently weak block is asking for trouble. But they will run for 20,000 miles at high 400's in power and if you can live - costwise - with that then go ahead.

It is no benefit to us tuners to have high power, low life useage, engines.

I'd rather talk you out of it than cross my fingers and let you talk me in.

David

 

lolol

 

My first engine failed at aprox 25 000km and was replaced under warranty. Ring failure...At the time i had only Milltek cat back and stock power-tune...after that i installed Nvidia catted DP, cosworth drop in air filter +custom tune and it lasted approx 70 000km until it failed again.This time it wasnt ring failure.Dealership told me that it was due to very bad fuel and bad detonation killed one of the pistons. Damaged piston had whole on top of it o.O is it because of the fuel or not i dont know but fuel is indeed very very bad in Serbia. I also had 2 head gasket problems in those 70 000km. Now it's time for 3rd one and the car will be ready to be sold!

 

To update you just had the pistons & rings replaced under warranty.Piston rings were sticking.
They also found a crack in the turbo & replaced that under warranty.
Running it in for 1000 miles fingers crossed.

 

Excellent (as in the warranty cover). Exactly how it should be.

 

Not me thankfully, That is why I send to your good self to machine them, jobs worth doing do it right as the saying goes

 

Just to add some positive input. Just traded in my 2006 Hawk STi after 7 years of ownership and with 37200 miles from new. No engine issues at all.
In fact this is my 6th subaru and nothing broke in ownership as usual

I should add that this car had the PPP upgrade very early in life.

Now on my 7th - new WRX STi saloon 13 plate.

 

Good to her Beastie and you will hear of lots who have trouble free driving which is great. Sadly though some will have the engine trouble and if only Subaru would have been loyal to them to fix, just as they were to Subaru with many buying lots of models through the years.

 

In fairness 37200 miles isn't something to be boasting about.

 

I'm not sure he is boasting.... just stating some facts, but I'd agree, it's not worth stating as it means jack in reality.

 

 

I am alive - oh there i go boasting again

 

Ah, so YOU'RE the Subaru STi customer for this year then...!

Joking apart, that's the first 2013 one I've heard of anyone buying.

Is the consensus that Subaru are now on top of the 2.5's problems?

 

There are no problems with the 2.5's according to Subaru .

 

haha, had to larf, mentioned the failures to one of the local dealer and they denied knowing anything about it

 

Perhaps because they haven't sold any of them...?

What a ridiculous state of affairs though.