Where's my boost?

Good suggestion Barnray, but took the muffler off a couple of weeks ago. Can see straight through, so no problem there. You've got me wondering though, had a snorkel fitted by others a while back. Is there anything under the gaurd area that could restrict airflow if not fitted properly? It's a Safari jobby.
Gerry

Check cat converter. B

Exhaust is 2.5 inch straight through. No cat converter.

Turbo was on the car when I bought it, but is proper kit for the 1Hz. Fuel is actually a tad on the rich side as EGT runs high under load. However, this should come down once I get some boost and hence more airflow. Dyno figures show air/fuel ratio to be OK.

I'm actually hoping it is something simple like a crack in the wastegate, but could be stuffed vanes or even stuffed bearings not letting it wind up. Guys at the dyno (Hi-Tech Diesel) suspect actual turbo but can't tell without taking it off the car and inspecting it.

I'm OK mechanically so will whip it off tomorrow for a look see.

Just thought that perhaps there may have been someone else out there that had experienced something similar.

Thanks for your suggestions though Barnray - always helpful
Gerry

Yes, I suspect the intercooler does has a fairly high pressure drop and it is something I have wondered about myself. However, Denco do seem to have a reasonably good name so I have assumed that since the i/cooler and turbo are supossedly matched to the car, that the turbo should be able to cope - but, perhaps not? I do have the old bits, so that is something I could try.
Thanks
Gerry

Gerry, before you start pulling turbo's etc off try to measure your boost pressure before the intercooler it really wouldn't surprise me one bit if the I/cooler is the problem and if that's the case I would be asking for my money back.
When you look at the number of tubes even in a factory I/cooler and compare them to the 4" diameter one it's very apparent which one will flow boosted air better.
Regards Andrew.

Hi,
Thanks for your reply and input. It still has me baffled I'm afraid.

The pressure for my gauge is taken after the water-to-air intercooler, just as it enter the inlet manifold so it is measuring pressure at the engine and at that spot is definitely 4.5 psi. The diesel place also confirmed this. Thinking the intercooler may be the cause, I measured the pressure just after the turbo and before the intercooler and made barely 1 psi difference - so that eliminates the intercooler.

To eliminate snorkel intake problems, I ran (not very long!) with the air cleaner box open and no filter - no difference.

I had already removed and checked the muffler a few weeks back, so that is OK. It's a 2.5" aftermarket pipe with nothing else in it.

All hoses are really short as the intercooler sits where the cross-over pipe normally goes, but all check out OK.

Yesterday, I removed the turbo assembly for a visual inspection. The wastegate mechanism looked OK, but I lapped it in a bit anyway, just to be sure. No excessive play in the bearings.

I removed the housing and found no signs of binding or rubbing although the clearance between the wheel and housing was a tad more than I expected, but that's probably just me.

The only thing I'm not sure about is what the bearings should feel like as they are oil type fed from the engine oil pump. While the wheels spin freely and smooth, they don't seem to run on for long. Could it be that the bearings are binding somehow and not allowing it to spin up to full speed?

Anyway, put it all back and physically "wired" the waste gate shut so it can't move, just in case the actuator is faulty and took it for a run. Bugga - still the same!

When driving, the boost starts to come up when expected, but gets to 4.5 and just stops there.

Might go back to the diesel people and see whether it's worth me taking it out again and having them take a look?

Anyway, thanks again for your interest.

Cheers
Gerry

P.S. The EGT gauge is working great! (free plug :)

Hi Gerry,

Strange one indeed. Yor initial post says "I think I've had the problem for a while as my boost has always been low at around 5 psi." Have you spoken to Denco about this previously? It's a long shot I know, but perhaps you've had a faulty turbo from day one?

I know it's not likely but maybe it was assembled incorrectly from the factory (with wrong size exhasut turbine for that size housing, for example)? Other than this, I'm out of ideas.

Please keep us informed.
Ian

Hi again (Ian from memory?)
You know, it's interesting, as that is precisely what I did today. Spoke to a guy at Denco who was really helpful. I need to get back to him with some casting numbers, but we may be a bit closer.

Apparently, there is an older model turbo for the 1HZ which was made before the company supplied the barrel type intercoolers. This turbo's maximum boost was only around 8 psi with the actuator set to 7.5psi. Therefore, if I happen to have one of these, and now with the intercooler fitted, I'm behind the eight ball, especially if mine's not that efficient any more. Since my car is a '99 and the kit was already on it when I bought it, this may well be the case.

However, all is not lost, as they subsequently made changes to the turbine housing (I think the wheel is still the same), which improved its performance by several psi. This overcame the drop across the intercooler and gave a couple of psi in reserve. I can apparently upgrade mine quite easily. (Don't know $$'s though!)

All I want is 7 - 8 psi... we live in hope!

Going away this weekend so I probably won't know anything until some time next week, but I've got all fingers crossed.

Cheers
Gerry