astra 1.4 8valve lpg turbo.
Turbo Mini Forums

I've just re-read the whole thread.

Discussion of pros/cons of PWM (or peak/hold) vs resistors started end Oct 2012 (1/2 way down page 4). I must admit I had forgotton most of what had been said.

The outcome seems to have been this,

Edited by Rod S on 9th Oct, 2014.

Schrödinger's cat - so which one am I ???

well...

while waiting for it to get REALLY cold ,and sit there with my injectors stubbornly refusing to open ,i thought id make a load more work for myself , since its raining perpetually and i cannot work on medusa .

i seemed to be hitting a mpg ceiling of 31 odd . and want to make it better .soo, i decided to try to reduce turbine back pressure by fitting a bigger turbo .this should improve cruising economy.

to make it easy on myself , i decided to use a t25 60 trim , with a .49 a/r (and much bigger turbine) ,thinking it might just have the same exhaust outlet as my t2 ....er NO!! like a dufus i had forgotten the t25 has a 5 bolt flange ,and the t2 a 4 bolt flangeness.....bummer ..








so i was in the rain ,alone, in the dark , ( ok not dark, but sounds better) , thinking hmmm , t25 or gt17 ....17 means i have to make a new downpipe ,and has a smaller turbine ,but more efficient ..t25 is bigger turbine so better for economy ,but little less efficient , but then again , im crawling along the bottom of the map at 8 psi , so not really sure it makes much diff , and the wheel on the t25 comp is curved blade and very very similar to the gt17 hmm..OK decision made , t25 it is .



so after offering up the downpipe off the t2 a hundred times , it would slide nicely over two of the studs , but not the other 3 ,







so i decided to make a whole new flange out of 10mm plate .and down tube .














chain drilling and grinding for a few hours is such fun ,but hopefully tomorrow i can get on with the down tube and get it on the blimmen car ....oi vay!


robert.

Edited by robert on 15th Oct, 2014.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

what about opening the wastegate on cruise? be interesting to see what effect it has.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I fully appreciate the effort in cutting out that flange,having made a new backplate for the A series to BMW gearbox conversion some time ago.

What I hate most is the mess !

good point denis i had forgotten about those dual port operated wastegate cannisters , i wonder were i can get one ?

i think joe was using one on his vnt thingmy.

ooops hold on i think i have one , but its an odd setup , it used air velocity at the turbo inlet to feed the other side ,presumably at a certain flow it causes a vacuum and limits flow .weird!

i'll have a look at it today when im not crawling around the floor firing welding sparks in my ears .



EDIT.. renault 5 seem to have them .

Edited by robert on 16th Oct, 2014.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Yes t2 from r5s have them

Yes i moved to the darkside

Instagram @jdm_brett

okey dokey..

1)r5 acuator in the post ,

2)downpipe welded up ,

3)now coming to terms with a bit of a boost increase since i thnik the r5 acuator is a bit more than 5 psi climbing to 8 like my old one was .

4) hanger bracket for rear silencer on order so i can put a box on the back and get rid of the motorway drone.

5) at this rate i might just have another go at the idle valve ms2 malarky!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

well lots of fun trying to get the big compressor circlip on with only external circlip pliers ,

only way to do it in the end was to zip tie the housing on and then i could use 2 hands to pull the pliers apart ....malarky!




check out my sexy r5 wastegate , double entry sexiness!




the down pipe was fun too, now done with a bmw stainless tailpipe section as the elbow ,, and it fits .








had to angle the wastegate down to miss the block by making the mounting plate 10mm high at the far end ,this is the clearance ,,,all a bit snug.




now have the air filter behind the grill ,for cold air ,,,,this makes a big difference with lpg.






and a general ,where's the turbo gone shot of the engine .







start up tomorrow and ,,,the big question ,,where will big bog off barstard 42mm compressor boost come in ? i'm guessing 2200 and 5 psi by 2600 and 10 psi by 3200/clutch slip!..

time will tell.

robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Robert! Double entry! Really :)

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

ok doke, test drive completed ,boost comes in at 1600 2 psi to 5 psi at 2500 when it comes on cam , then 9 psi at 2900,so it feels much the same low down as before ....happy.

bit of mapping then dyno power test to compare .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

that sounds quite reasonable

Yes i moved to the darkside

Instagram @jdm_brett

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

We'll done ! Good luck with the run

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

thanks graham ,

i now have to resist my ailment ,

the latin name of which is ,

'maxusboostus pedaldownus'

an offshoot of 'bigturbinus topendbananas' syndrome .

a nasty affliction that affects economy badly .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

It would be nice to see what happens with a couple more psi of goodness.

Not if you're relying on it to get you to places mind.

In the 13's at last!.. Just

I had been wondering for a while what the proper name was for that ailment, which does seem to be particularly prevalent among this gathering.

I have suffered it myself in the past.

I've a feeling whether you've improved economy will depend on you're gear ratios and if you're on boost or not whilst cruising on the motorway.

now spent a few hours rigging up a direct inj feed on cranking ,started straight up after refusing to run this morning in 9c , i wonder what will happen in -10c ? may have to rig up a solenoid to inj gas on a switch .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

back again,

orl righty , i thought i'd have blunder about with the idle control valve.

so reading this ..

http://www.diyautotune.com/tech_articles/m...tepper_iac.html


i changed time step to 10ms ..no effect .

then tested for any voltages at the iac plug ,... no voltages at any of the 4 pins. did this with engine running and not running .

then switches off iac and switched on the spare ports 6 and 7 and used the throttle to send signal ,nothing , tried with both engine running and not .

also did the tests with the iac step page open trying different levels to see if it would provoke anything .

so no luck so far ..it appears there no signal going to the plug at all at any time .

i'm still on the archaic software not having had time to swap and redo my settings .

im guessing i either have the wiring wrong ,,the software wrong , or i have some how damaged the chip.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Load the latest firmware version, make sure you have the jumper between JS9 and S12C (which does provide 12V to the IAC chip) and use the test mode to check your output.

http://www.jbperf.com/

i think thats probably the best idea jean , like rod said earlier ...just dont have the time to quickly retranslate my settings ,but hey i'll get to it hopefiully end of the week .

in other news ,during my 600 miles i have done in the last 2 days , 165 of them were done in the stealth estate .

i drove to sheppers ,with the timing a bit backed off ,say 3 degrees just to be sure on the 9psi setting ,and was a little underwhelmed, no real change in torque from 4 to 9 psi .

oh ho ! i thought , too much retardationosity.

so , after doing 200+miles banging up and down the m4 in a v12 db7 , and finally getting to set off for the 80 mile drive home at 9pm last night , i thought , first ,lets map that ignition again .....so bunged in 3 d advance in the 9 psi range ...then set off for the 20 miles twisty thrash to bath ...


all i can say is , holey moley !!

what feels like about 50 lbs ft more .....surging up hills at 80 to 90 ,massive difference , cannot wait to get it on the dyno ..nearly ran into numerus hairpin bends ,and set new 1 hr 35 m record for the trip ,just a massive change in the car.

,now suffering a lot of 'maxusboostus pedaldownus'


i think i might forget this economy data...



oh , edit to add , i did notice towards the end of the trip , in higher gears on full bore acceleration a new rev limit occurred at 5500rpm ... im hoping this is because the tank was nearly empty,,and not because i hVE NOW REACHED FULL INJ CAPACITY ON MY 15 PSI FUEL PRESSURE SETTING .... RAISING THE PRESSURE WOULD HELP WITH THIS BUT NOT HELP THE TICKOVER ..ooops damn caps .

Edited by robert on 26th Oct, 2014.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I assume that 15psi is absolute as opposed to relative or is it irrelevant?

its 15 psi gauge rob so around 30 psi absolute .

its may be, now its all a bit more stable and setup , that i can run smaller pulse widths than 4ms , i think rod was talking about 2.3ms a while a ago , so i may be able to raise fuel pressure .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Yes i moved to the darkside

Instagram @jdm_brett