ALFAGTV6.COM

[Jim K]

Don't laugh, it ain't dead yet and it its not about to die! It just came alive! All it can do is grow and I'd say this is a damn good start!
Jim K.

[Mats]

Power dies at 5000 rpm? 75 1.8 Turbo Diesel But it should do well with a 3.5X gearbox.

Exactly like the factory installation...

Jim, not sure if you're aware of this but I found the most evil stock Alfa cam for the Nord to be the intake cam on the 75 2.0 carb with VVT. Over 11mm lift IIRC. The head is modified to take the higher lift.
I have a couple I can send over for science.

Free of course.

[Jim K]

Mats, this cam has been in the 4-cyl book for ages! Its actually 12mm with 256*@1.25mm !
Jim K.

[Mats]

So why don't you use that one? Perfect for turbo it seems.

[Jim K]

Seems the TS is a bit too much for my 1.8T. I get the best results by using a 10.7mm lift, 242*@ 1.25mm cam (which I also have here) for the intake and the 10548... in the exhaust -so say the simulator tests, where with this combo power is flat and stays there until over 6400!! Before I try this, I'll replace the afm with the big one first and see if there's an air limitation there. Looks like little-by-little the 2854 may prove to be an excellent choice for a daily/trackday tool!
Jim K.

[Mats]

What do you mean TS?
Too much? Duration? Open too early o what?

EXPLAIN YOURSELF!

[Jim K]

What I'm saying is the simulator shows the best overall gain with a 10.7mm 242/1.25mm cam and not the TS cam (12mm, 256/1.25mm). Surprise-surprise... It so happens, the former cam is a special 1.8T cam I bought a few years ago from Italy and I input the details in the simulator program! Maybe those guys knew what they were selling, as they also supplied a very detailed dyno graph with all kinds of info along with it. They also used 1.4bar (with the std turbo and std CR) and their output was 228hp/5210 and 372Nm/4000. Hmmm, its reasonable for the old T3 to peak at higher rpm than the GT2854R and to have less power with the std CR. Judging by their results, I'm not doing too bad for first try. Like I said, I'll put the large afm in first just to remove it from the flow equation and if nothing changes, then its time for the cams.
For comparison purposes as far as power numbers, remember that race 1.8T's in 1990 made 204hp/6000rpm, 285Nm/4500rpm with 1.4bar (7.1:1CR), 280hp/6000rpm, 440Nm/5000rpm with 1.5bar (7.5:1CR), 400hp/6000rpm, 667Nm/5000rpm with 2bar (7.35:1CR).
Jim K.

[Mats]

I must be missing something here... TS cam? Where did that come from? The can I'm talking about is from the 2.0 Nord with carbs tht existed pre -88. An actual cam and not just cam data from another engine.

[Jim K]

Aw, $hit! I thought you were talking about the TS intake cam all along! That's why we're all confused!
Hmm, I measured the one you propose ages ago but I can't find the graph! I'll have to find one in some Alfa shop here and graph it out again. It has a beefy lobe and they use them for all kinds of Alfa regrinds here.
Anyway, as I said I have a good intake cam and it will be the next step after the big afm.
Jim K.

[Mats]

[Jim K]

Today I finished transplanting the 1.8T afm innards to the large ex-BMW afm (30% larger area). I'll have to find some 80mm hose pieces plus make an intake ring/horn for the turbo intake to connect the 80mm hose. When done, it'll be a much better arrangement than I had up to now. There will be ~40cm of 80mm wide connection between afm/turbo -since afm output/turbo input are both 80mm. I'd finish it today if I had the necessary bits and pieces but I have to go to the machine shop for some of the parts. Anyway, I should be done with all this in a few days and resume testing again. Very curious to see if the std afm limits air intake and to what extent at elevated power levels.
Jim K.

[75evo]

Didn't you say you were going with a Coupe 16V T marelli efi?

BTW would VVT have any big effect on a turbo car, performance wise?

[Mats]

I depends...

If you're looking to get spool waaaay down in the rev range (possibly because towing caravans?) it may be a good idea but for us who like to rev it it's really not a factor.

[Jim K]

With my current GT2854R, I don't think vvt would be of any advantage; probably not worth the trouble, as it goes on boost ~2200rpm and full boost under 3500.
I'm almost finished with the big afm install. It actually looks nice! I'll start it up tomorrow and do clockspring settings with the wideband for easy driving around town (afr's 13.5-15.5) and the CO% will be set with an analyzer to 1%. Then, its up the steep hill again, heheh! If all goes well, back to the dyno. ....Bear with me guys and don't be too impatient...every time I get on the rollers, I'm out 50€!!

I do have the Weber/Marelli P8 (from the 16vt) and the Webel L6 (Sierra Cosworth rwd) but the point is to go through all the lower stages before I get to that -which is the final stage. I'll say again, I am going to use the std fuel ecu and afm for now. With this turbo and the 1.4bar max, I believe the top is ~245-250hp and ~380Nm. I am very close to that but I'll quit this stage when I 'flatten' the power curve to ~6400. If the big afm doesn't do it, cams will. I will then be satisfied and move on to the GT2871R. This will be an interim stage, as this turbo will comfortably allow 1.8bar. After dyno in this configuration, THEN its time for the P8 ecu. We're then possibly looking for over 300hp at these boost levels.
Most people here use the L6 ecu and they make 270-290 wheel hp, after mapping of course. Its a matter-of-course 1.8T upgrade; don't know who started it but it works fine. Funny thing is I have two complete sets of L6 stuff! Back in the days when I didn't have money worries, I bought another set as a spare! However, the P8 is way more advanced, expensive and capable and also uses the knock sensor.
I'll be back with some preliminary results soon.
Jim K.

[Mats]

You talk alot about compressor trim but what about your exhaust housing sizes? A low compression two valve engine doesn't like backpressure and usually the new turbos are all balanced for highish 9.5 and up CR four valve engines (i.e. Large compressors and small exhaust trims to get them to spool quickly). Back pressure will kill any turbo install and you can have any cam in the world but the engine won't care..
The first part after the turbo is also very important and if you have a 2.5" downpipe with a couple of tight radius bends in it...