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Re: 4-cylinder turbo performance

Posted: Tue Apr 23, 2013 4:12 am
by Mats
I'll trade you a flat valve cover for a 1.8i front cover... 8)

Re: 4-cylinder turbo performance

Posted: Thu Apr 25, 2013 3:46 am
by Mats
Does the 1.8ie have a distributor with a hall-sensor by any chance?
Would be nice to have a cam-sync signal. :)

Re: 4-cylinder turbo performance

Posted: Thu Apr 25, 2013 5:04 am
by Jim K
Yes, that's what it has. Its also locked, as the advance curve is ecu-generated.
Jim K.

Re: 4-cylinder turbo performance

Posted: Thu Apr 25, 2013 8:49 am
by Giuliettaevo2
The 75 1.8IE's i know off don't have a sensor in the distributor.. :? They're motronic cars with just the TDC pick up on the crank pulley and an empty dizzy...

Re: 4-cylinder turbo performance

Posted: Thu Apr 25, 2013 9:15 am
by Jim K
Hah! Good correction! I thought Mats meant the 1.8Tie ... I may need a second pair of glasses! :shock:
The Turbo has such a distributor and one of the 33's -the 33 one also has a vaccum pot.
Jim K.

Re: 4-cylinder turbo performance

Posted: Thu Apr 25, 2013 10:53 am
by Giuliettaevo2
probaly the 33 with the Jetronic injection. Jetronic often uses a hallsensor in the distributor.

16v 33 used Motronic and has empty dizzy. 1.4 used Magneti Marelli, don't know what's in there.

1.7IE from the earlier models had Jetronic later models had Motronic with DIS ignition so no dizzy.

Re: 4-cylinder turbo performance

Posted: Fri Apr 26, 2013 12:57 am
by Mats
Jim, that one is called 1.8Tb if you want to add letters. ;)

Have been looking at a replacement Hall sensor for VW distributors, it's the complete unit with sensor, mounting plate, connector and the trigger plate itself. It's made for four trigger pulses per revolution but I'm figuring I can just cut off three of them.
Not sure I need it but in the process of making it "futureproof" I might do it...

Re: 4-cylinder turbo performance

Posted: Fri Apr 26, 2013 5:11 am
by Jim K
The 1.8T was (also) called 1.8Turbo ie and some years even had this plaque fixed to the trunk lid, others (like mine) said just 75 Turbo.
The Hall mechanism you want is available as a spare part; I've seen it in some stores -no idea of cost, I never asked. If you have a busted Jetronic V6, they also had it.
Jim K.

Re: 4-cylinder turbo performance

Posted: Fri Apr 26, 2013 7:58 am
by Mats
True, the V6 distributors ar larger though. But I'll check.

Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 8:23 am
by Jim K
Ok, went to the dyno today, to see what the 1.8T is good for in its latest guise. Before you start bitching, my goal is to investigate performance gains in definite steps, starting from stock and moving up gradually. This means retaining as many std components as possible and adding/substituting from there.
The present state of tune is:
Head milled for 8:1CR
Nava O-ring head gasket
10548... intake cam
Aeromotive fuel pressure regulator
63mm exhaust throughout, two free-flow mufflers
MSD 6530 programmable ignition
3bar map sensor
Std intercooler modified for water cooling +small radiator + recirculator pump
Bosch 0580254909 fuel pump
Weber IW-044 injectors
Garrett GT2854R turbo
Total cost for all above ~2300€ of which 1000€ was for the turbo.
Note that results were obtained with 1.4bar (~21psi) boost, while afr was 11-12.5:1
Observations: The fact that we are seeing very low rpm can mean several things, like air restriction, small turbo or cam timing. Air restriction: I'm still using the std afm and fuel ecu. One upgrade under way is to use the large afm from the BMW635 with the Alfa 1.8T innards. I already did this and I must now do the physical connection with larger diameter rubber pipes to the turbo. The issue of cam timing will be dealt with by trial/error re-timing and probably another dyno visit. The turbo issue was to be expected but the initial goal was to make one of the best possible (?) road-going 1.8T's. After this series of tests is completed, I'll install the GT2871R, which will open the door to high power -over 270+.
Jim K.

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Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 9:01 am
by Mats
Do you still have the terrible stock intake arrangment on the suction side of the turbo?
Did you try different boost levels?

Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 9:18 am
by Jim K
No, the 'snake-pipe' is gone and the afm is connected with a short Samco to the compressor.
I tried 1.2bar, 1.4, 1.6. 1.2bar verified I had the old hp level (220hp) at the same boost and 1.5-1.6bar was dropping a lot -look at the compressor map and it will be clear why it dropped. I think 1.4bar is actually the max usable for the 2854 with this engine. I am seriously suspecting the exhaust cam and head flow capacity. A friend's 1.8T picked up quite a lot after a porting job, but this is still a few steps away from now. I'll try re-timing, possibly using a 10548... for the exhaust also...we'll see.
Jim K.

Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 9:32 am
by Mats
Would be very interesting to see what happens if you put a longer pipe in between the airflow meter and the turbo...
Turbos does not like dirty air into the compressor, so if you have only a short pipe/small volume in between them it might be detrimental to the power.
What's the cam timing like? Exhaust temps?

Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 10:22 am
by Jim K
I'm using the std (pitiful) exhaust cam, 252* duration with 108* LC. Std LC is...115*!!! I may use another cam there, as this p/n is one of the smallest ever made by Alfa. Fortunately, there are 3-4 better factory steps between this one and the 10548...
I will try for a better intake pipe arrangement together with the bigger afm.
Jim K.

Re: 4-cylinder turbo performance

Posted: Wed May 08, 2013 10:48 am
by 75evo
Power dies at 5000 rpm? 75 1.8 Turbo Diesel :mrgreen: But it should do well with a 3.5X gearbox.