sorry to but in. i usd a 1400 open chamber head to lower comprshion on my 1200 years ago but these are rare you can have a decomprshion plate made

crome rings are generly no good for a series as the bore is to soft i found out the hard way

really worth your time reading this info for your turbo setup choice when you have picked out the motor you like.

http://www.turbobygarrett.com/turboby ... center/turbo_tech103.html

The guy at the turbo shop would have the compressor maps handy if he is saying those turbos are ok?. Looking back at your posts on this setup it looks very much like those turbos are not a good match at all in their present config.Have a look at the garrett site and you might be able to work out where to aim some numbers at. Aim at nothing and you hit it every time as they say.

I think the twin setup will be easier to sort with a few more cubes as well..GO the mighty A15!

i haven't had time to read all this, but the short answer seems to be lack of tune and inadequate waste gates to keep the turbos in check.

compressor maps are fairly easy to read, garret even has a tutorial in reading them.

seems that the lack of tune blows up rings, there may be better rings out there, but that's no fix, getting a good sleeve put in and getting the block o ringed would help, but you still need to lower the static compression if you want to run 15 psi on pump gas!

a knock sensor would be part of a engine management system, but if someone wants to make one that will dump the vacuum advance ( maybe even retard the mech advance???? ) as knock gets louder, that should be fairly easy.

maybe get a motor that's reliable for 50,000 miles at 5 psi then crank up the boost as you can get it running properly.

it's easier to run high boost with MPFI... carbs are going to have issues that kill motors. ( yes even well tuned ones some times have problems that mpfi can never have and kill your motor. )

umm i know how to read compressor maps nbut these ones dont have them. if you can find some compressor maps for the stock turbo on the daihatsu, that would give 1200rc all the info he needed.

The set up ran well for what it was in blowthru set up... it did not get these major problems until efi kicked in... probably the tune and maxing out the injectors etc made too much power for the set up therefore making the turbos flow outside their maximum.

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Dont know how long the engine will last. Even the slights ping does small amounts of damage.

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correct me if I'm wrong, but your dyno graph showed something like 100bhp at the wheels? And your best quater mile was 15.something? Are you sure those WRX's skylines and commodores knew they were racing?

I've said it before - street racing proves nothing.

they were a couple of my good mates, a lot of pride was at stake, they were racing...

both the dyno and quarter i did when the car had a lot of bugs, you know that, im not going to explain that to you AGAIN

unfortunately i havent done either again when the car has been running better

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literally... as the sensor hears it, it can't retard the timing if it's not making any knock.

measure the combustion chamber volume before using that head you have found.
Don't assume that the hole looks bigger so I must be.