original pistons

[Nappien]

im just wondering how much force can the original pistons on a 1992 vr4 handel?
is it true that these pistons have their weak spots round the edges?
can they handle 20psi(1.4Bar) with no problem?
when should the pistons be changed?
can i use the rods from original pistons when going to forged pistons, or do i need new rods as well?

jupp..piston questions :D

[Drweldin]

I think most would agree the 1st gen TT pistons are better than the 2nd gen because of the much thicker ringlands. I have thrown 20 psi at mine for a while without issue. This assumes a good tune of course...of course 20 psi is a relative number also, I assume youre talking about a td04 class turbo...
I would say anytime you go outside the realm of td04 you would consider forged.
You can use the rods on new pistons.

[fastnelson]

im just wondering how much force can the original pistons on a 1992 vr4 handel?
is it true that these pistons have their weak spots round the edges?
can they handle 20psi(1.4Bar) with no problem?
when should the pistons be changed?
can i use the rods from original pistons when going to forged pistons, or do i need new rods as well?

jupp..piston questions :D
All depends what you wanna have/built really.

[pos-vr4]

the tune is the key to how long they will last with higher boost.

The last three 6g72 i have torn down has has broken pistons.

[Nappien]

i have 550cc and turbos whos housing is bored out over 7mm, and open air filter, tanabe exhaust..
the thing is that one of the pistons broke when at 1.4Bars, so im just wondering what is to be expected from the pistons :D lifetime and such

i am now going for forged pistons(wiseco) second time around..

[fastnelson]

i have 550cc and turbos whos housing is bored out over 7mm, and open air filter, tanabe exhaust..
the thing is that one of the pistons broke when at 1.4Bars, so im just wondering what is to be expected from the pistons :D lifetime and such

i am now going for forged pistons(wiseco) second time around..
i think you have really bad tuning problems

[Nappien]

i think you are right..im using a diffrent workshop this time..the other workshop got the base map wrong and drowned my start plugs..

are there other things i should look at..is the crankshaft and camshaft strong enough for a little more power..ive heard of people getting 400bhp+ with stock

[MightyMouse]

they will handle 20 psi on the typical bolt on turbo IF tuning is in check. Timing with 550s being your biggest hurdle. I'm currently running 18 psi on my 10:1 with dr650s and e85. Pistons are fine. Crank and block (1st gen cast and 2 bolt NA) are the weak links.

[Nappien]

just some pics on how its going..engine out, and it will be ready to ship to a engineshop for overhauling after the weekend..i hope :)

http://img716.imageshack.us/i/img0141f.jpg/

http://img25.imageshack.us/i/imag0031mp.jpg/

http://img716.imageshack.us/i/img0141f.jpg/

[blindmist]

http://imgur.com/KSZ0o.jpg

I was 13psi with my 13t's. You tell me what happened. I am still trying to figure it out. I haven't had anything really changed at that point.

[CoreyB]

Bad wrist pin ?

[Nappien]

It's all to do with the tune and the fuel's octane rating. It's just that forged pistons can handle more abuse before they fail.

If you get it wrong with stock pistons you'll break a piston and nothing else.
If you get it wrong with forged pistons you'll destroy the pistons, the rods, block and the gearbox.

Steve

omg im getting nervous now..seriously :O

fuel im using is just 95 nonlead..or maybe 98..no e85 here as its so rare :)

im just hoping the guys who will do the next tune up will do it better than the first shop. But couldnt it be that the piston was just old? worn? been thru allot? :D i will get hold of receipts from previous owner on how long these pistons had gone..last thing i heard that the pistons might have been 130k miles old..but block had been overhauled in 2003 and maybe he changed the pistons as well..but have no clue.

if ill destroy more pistons, rods and such i will drop into fetus position.

who can have a nice tune made up already? for 550cc and such..

[Nappien]

I was 13psi with my 13t's. You tell me what happened. I am still trying to figure it out. I haven't had anything really changed at that point.

overboost?

air/fuel ratio is off?