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Qwkswede's 1992 244 daily driver. Back to my rolling roots.

Turbocharging Failures.

I'm a bit annoyed that I wasted a good part of my weekend on a failed turbocharging experiment. I knew I might be facing some slower spool up with the Chinese turbo, but I had no idea I would end up where I am. I still feel like something else is amiss with the motor. But I don't have the energy to tear into it any more at the moment. It is spring, and I need my Volvo to haul bikes and other crap around the mountains. So I'm just going to drive it for now.

On the upside. It looks great under the hood. The larger turbo fits pretty nicely. I fabbed a decent intake pipe setup, and a new downpipe, and a wastegate actuator for the t3/t4. I did some porting on the 90+. Win win win and an A for effort.

IMAGE_1370.jpeg


The sad reality that I should have guessed would end this way. The tbricks voices in my head murmuring "it'll never spool". I have run this turbo on similar combos in the past, and I don't think it was quite this bad. Maybe my T3 was just fine, despite the cracked housing. The T3/T4 is solid now, no smoke. But just pathetic in horsepower

Full boost at 5500rpm?? Maybe? I don't know because I shift at 5000. The wastegate is set for about 15psi, and I can't even reach that.
slower_spool.png


I do have a few other tasks to get done on this car, I just wanted to see more power first.
To do list:
-Install the built AW71.
-Install the G80 diff I have.
-Do a burnout.
 
After all this nonsense and monkeying around I'm left wondering what would be an ideal turbo for this car. I found in my boxes a .48 AR turbine housing that would fit the Garrett I have. It is a turbo dodge 2.2 turbine with the nice wastegate setup. That would help spool up I'm sure. Not sure I would like the top end, but probably not a bad choice.

I also could pick up a Mitsubishi of some sort really cheap. A 15g, or other common take off from a whiteblock Volvo. That would bolt on to the current 90+ manifold, and need just a little downpipe and intake tweaking.

Anything else that spools like that, but with better top end power? Even if it costs real money?
 
So since the last go round I have done a few things.

1. Intake pressure test was good, It holds pressure all the way to the tailpipe.
2. Messed around with the wastegate actuator rod, tightened the pre-load considerably, no change.
3. The throttle opens wide. I did adjust that for a little more opening, but it was close enough before so no real change.
4. An exhaust restriction was suspect with the dying catalyst, but that problem is no more. No more cat, and its loud and hollow sounding now. It does pull better at the top end, and revs a bit more freely just not in a boosted way. Bigger turbo and free flowing exhaust will do that I guess.
5. Found the crack in the t3 turbine housing, it looked pretty bad. So I swapped turbos. I wanted to end up with the bigger turbo eventually, but not with the current performance. So I'll stick with the currrent turbo for a little while.

Things I haven't done yet, that I should.
-Bypass the intercooler, maybe there is an animal or a sweater in there.
-I think I'll do a leakdown test this week, just to get a bit more information about the motor condition. I think the problem must be here internally somewhere. This was the slowest NA car I have ever driven by a long shot. I think this problem pre-dates the + turbo stuff.
 
yeah something's up somewhere, it shouldn't be that slow with the little cracks in the 60 trim,
 
Drive it open downpipe and see how it runs. Bypass the intercooler.. Its got to be something there.. If its the engine I have no idea what it would be..

-Sam
 
I picked up a stock 740T intercooler from my Volvo parts suppliers on the way home from work. I swapped the NPR for the stock Volvo and magic happened. I had to loosen the boost controller about 3 turns so far because I keep hitting the high pressure cut I set in Megasquirt. It is time to get her tuned up and enjoy the ride! The china turbo feels about right now. It spools slightly slow, but hits hard at about 3000 rpm. Thats about what I expected with an automatic car.

The NPR looks fine inside. But it must be loaded with grease or dirt in the tubes. I dunno, its a mystery. I have run a couple of them in the past with good luck. I like the way the stock volvo cooler fits better anyway. It gives me some room to mount the engine oil cooler if I want. I wonder if its worth filling with some solvent to clean up the insides.
 
qwkswede said:
I picked up a stock 740T intercooler from my Volvo parts suppliers on the way home from work. I swapped the NPR for the stock Volvo and magic happened. I had to loosen the boost controller about 3 turns so far because I keep hitting the high pressure cut I set in Megasquirt. It is time to get her tuned up and enjoy the ride! The china turbo feels about right now. It spools slightly slow, but hits hard at about 3000 rpm. Thats about what I expected with an automatic car.

The NPR looks fine inside. But it must be loaded with grease or dirt in the tubes. I dunno, its a mystery. I have run a couple of them in the past with good luck. I like the way the stock volvo cooler fits better anyway. It gives me some room to mount the engine oil cooler if I want. I wonder if its worth filling with some solvent to clean up the insides.
Click to expand...

it's worth it. clean the npr out if you can.
 
Man, that's crazy. I really wonder what's inside that's plugging it up enough to do that kind of damage performance-wise. I've been rocking the NPR in my wagon for 6-7 years now, plan to swap to a do88 unit before my next smog just for the stealth factor. That NPR has seen a lot of use and abuse, spikes to almost 30 with no problems whatsoever. Funny, 100* ambient, IAT's were dropping when in boost compared to IAT's when not in boost. lol
 
I'm wondering, could you have looked at mass air flow readings and figured out that there was an intake flow restriction? Might help others troubleshoot in the future.

Glad to hear you found the problem.
 
I don't think that a MAF would have helped even if he had used it, as it would have registered low airflow regardless of whether the intercooler was plugged, the rings were fried, valves burned, or exhaust pinched. Best way to tell would have been to put a gauge or pressure sensor before and after the intercooler. Much easier to swap intercoolers at that point anyway.
 
Yeah, I thought about installing my boost/pressure gauge before and after the intercooler a while ago, but didn't have the parts handy. And a plugged intercooler? pffft. Who ever heard of that? The intercooler swap was an easy test, and I was able to pick up a stock one from a friend on a whim. I looked everywhere in the intake and exhaust tract for leaks and restrictions. I only suspected the intercooler because there was nothing else to try.

I ran this setup with LH2.4 for a while. But you can't really monitor airflow very easily with LH2.4. I honestly got more information from looking at the datalogs with Megasquirt. Watching the manifold pressure climb so slowly was enough to tell me there was a leak or restriction somewhere.

harribert said:
I don't think that a MAF would have helped even if he had used it, as it would have registered low airflow regardless of whether the intercooler was plugged, the rings were fried, valves burned, or exhaust pinched. Best way to tell would have been to put a gauge or pressure sensor before and after the intercooler. Much easier to swap intercoolers at that point anyway.
Click to expand...
 
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