11 replies to this topic

[kipper]

Anybody had experience of these, are they worth the money in terms of performance and longevity?

 

Thanks

 

Dave

[Nev]

A bigger compressor has to help surely, both by reducing IATs and increasing max power (particularily at higher revs) if you want? I think Steve (Sizetenboots) has/had one.

 

 

Edited by Nev, 21 February 2015 - 03:06 AM.

[kipper]

Double the price from a  'standard' K04 to K06 with billet compressor wheel...bit worried about the reliability, taking OEM and just modding parts, and not the whole...but hang on a minute..is that not most of us do

 

I'm sure that Steve's comments will be along shortly......

[siztenboots]

get a k16

 

http://www.vx220.org...s-to-360380bhp/

[kipper]

Thanks Steve,

 

Really want to keep standard internals, so safely limiting to say 300 BHP. Any modified turbo I would like to have some form of warranty, in case of it all going pear shaped...so if Cournteny fit it there is a 12 month warranty... I know I'm being a bit of a whimp, but really havn't got time for large engine rebuilds at the moment...that might change when I get to rebuild the spare engine sitting in the garage, some time in the future

[Nev]

Kipper, it's a bit of a myth that 300 BHP is the absolute ceiling for a reliable Z20LET without internal mods. The reason for this (IMO) is that CS are very wary of any engines they fiddle with going bang. They only have to have 1 in 100 go bang and their name will become mud, so they err on the side of strong caution. In Germany etc, there are plenty of 330, even 350 BHP standard Z20LETs running around for many 10 of thousands of miles. If you are willing to take a bit of a chance, it is possible to push the limit to 330 BHP with moderate confidence with the larger turbo. The key to the rods not failing is likely to be too much torque, so if the map deliberately avoids the mental torque (ie stays below 340 ft/lb) I think you'll be fine. ie the torque can remain the same as a standard Astra turbo, but the bigger compressor will blow harder at the higher revs, hence giving you more BHP for the same torque. Give me a ring if you want

[mbes2]

I think for road use its going to be safe (ish) ... on track would be a very different story

[kipper]

Kipper, it's a bit of a myth that 300 BHP is the absolute ceiling for a reliable Z20LET without internal mods. The reason for this (IMO) is that CS are very wary of any engines they fiddle with going bang. They only have to have 1 in 100 go bang and their name will become mud, so they err on the side of strong caution. In Germany etc, there are plenty of 330, even 350 BHP standard Z20LETs running around for many 10 of thousands of miles. If you are willing to take a bit of a chance, it is possible to push the limit to 330 BHP with moderate confidence with the larger turbo. The key to the rods not failing is likely to be too much torque, so if the map deliberately avoids the mental torque (ie stays below 340 ft/lb) I think you'll be fine. ie the torque can remain the same as a standard Astra turbo, but the bigger compressor will blow harder at the higher revs, hence giving you more BHP for the same torque. Give me a ring if you want

 Thanks Nev, I understand its not the ceiling, it was just a figure that I was aiming for, from the cost/ BHP point of view.

 

I'll take you up on your invite of a call, when I get back in the UK.  However, better finish installing the charge cooler before I move on to other expensive outlays.

[joshua]

My car has a hybrid of some sort with larger compressor wheel and cut back exhaust vanes.

 

With this fitted and both times on Courtney's dyno stg4 went from 290 @5400 to 312 bhp @5700 and 300bhp @7200 with no other changes.

EDS inlet and Dbilas turbo housing/manifold since added and noticeably faster still but not had it back on dyno yet.

 

There is an argument to suggest these hybrid turbos are more reliable than standard as they don't need to overspeed to achieve higher boost.

[scw02102]

12bhp loss from peak to 7200rpm is pretty good (im guessing the bigger blower helps) Just checked a few of my old graphs and my looses approx 20-25bhp from peak power to 7200rpm Think the std little turbo runs out of puff

[kipper]

My car has a hybrid of some sort with larger compressor wheel and cut back exhaust vanes.

 

With this fitted and both times on Courtney's dyno stg4 went from 290 @5400 to 312 bhp @5700 and 300bhp @7200 with no other changes.

EDS inlet and Dbilas turbo housing/manifold since added and noticeably faster still but not had it back on dyno yet.

 

There is an argument to suggest these hybrid turbos are more reliable than standard as they don't need to overspeed to achieve higher boost.

Thanks for the insight, this is very helpful. Any details on the hybrid? Looks like I might go down the K06 route.

[siztenboots]

from someone that has done all the various steps, carstens VX upto about 400bhp

 

basically for the k04-0049 LEH turbo , they all do the same response/lag , we just limit the overboost torque , light green/orange/red lines , top end mostly comes down to cooling

 

I think the K16 would give anyone that OMG its going to kill me feeling , torque is about the same, so rods should cope, but its held for longer more bhp , the 2.2 rebore build is not really needed