Limited Boost on 3L

[grepin]

Hi all.

I have a Garrett turbo setup on my 2.8L Diesel Hilux. It has a 0.48 Comp housing on it. I hooked up a gauge and it shows 5 psi. I thought I might try and make it run at 8-9 psi like some of the DTS setups seem to. I tried a bleed valve which didnt work and then tried just taking the wastegate out of it all together. Still only maxes at 5psi. Checked all hoses and clamps and there doesnt seem to be any leaks.

I guess from here I either have a too smaller turbo, or back pressure or fuel needs tuning maybe.

Anyone have any ideas. I dont know the history of when it was setup.

Thanks

[hilux79]

What exhaust system do you have?

Some old school air research systems used to use restricted exhaust systems to limit boost ie. holden 202.

Are you sure the gauge is good? Can you swap it with a mate to check?

Did you actually take the wastgate out or just the actuator and wire the wastgate closed ( not something i would recommend). As if you pulled the wastgate out you will have very low boost if any.

[grepin]

What exhaust system do you have?

Some old school air research systems used to use restricted exhaust systems to limit boost ie. holden 202.

Are you sure the gauge is good? Can you swap it with a mate to check?

Did you actually take the wastgate out or just the actuator and wire the wastgate closed ( not something i would recommend). As if you pulled the wastgate out you will have very low boost if any.

Looks like the stock with a bit of a dump to it.
Brand new gauge. Regardless of if the gauge was accurate or not I wanted to see more boost.

Actually disconnected the hose to the actuator so it stayed shut. Blocked the hose naturally so boost wasnt lost. At peek revs it still only indicated 5psi with wastegate staying shut. Now this is assuming the actuator is keeping the wastegate shut under boost. By hand it seems to be holding the wastegate shut. The spring in the actuator could only be rated to 5psi then thats all I will ever get.

Next would be to somehow hold the wastegate shut and see if I can achieve more than 5psi boost using my foot to control it.

I have had turbo experience before with a Skyline so not a novice with the theory of turbo mechanics. Just new to Diesels really. It is a bit of a boonga so not getting to wrapped up in it. Just thought I would see if I am getting the best I can get with what I have. If 5psi is it then fine.

Thanks for the reply. Let me know if you have any theorys.

[Willy Hilux]

I got 15 psi out of my DTS kit on my old 3L. May need to wind up the fuel mixture to get more. I know this changed mine when I was playing with the boost.

[80's_delirious]

if its not getting enough fuel, boost will be limited.

more fuel in= more gas out = more boost = more air in = opportunity to add more fuel and so on.

I had my boost controller (80series) set at 14 psi, adjusted the boost controller (waste gate) up, but got no more boost, after adding more fuel, boost went up to 18-19psi.

Next would be to somehow hold the wastegate shut and see if I can achieve more than 5psi boost using my foot to control it.

have you checked the boost when driving it. find a long steep-ish hill that needs third gear, give it full throttle from around 1500rpm right through to red line and then see what boost is produced.
Without load on the engine, it will produce very limited amount of boost. Free revving the engine while parked probably wont see more than 5psi.

[grepin]

if its not getting enough fuel, boost will be limited.

more fuel in= more gas out = more boost = more air in = opportunity to add more fuel and so on.

I had my boost controller (80series) set at 14 psi, adjusted the boost controller (waste gate) up, but got no more boost, after adding more fuel, boost went up to 18-19psi.

Next would be to somehow hold the wastegate shut and see if I can achieve more than 5psi boost using my foot to control it.

have you checked the boost when driving it. find a long steep-ish hill that needs third gear, give it full throttle from around 1500rpm right through to red line and then see what boost is produced.
Without load on the engine, it will produce very limited amount of boost. Free revving the engine while parked probably wont see more than 5psi.

Looks like fuel is the go.
I drive around with a boost gauge connected daily.
Never more than 5psi. Up hill. Pulling load 120km/h.
Whats the implications of adding fuel is there dangerous levels?
I would only consider maybe 9psi. Is it something to be done on a dyno?

[80's_delirious]

more fuel produces more heat, too much fuel and it will use lots of fuel, blow black smoke and with the extra heat you risk damage to turbo and engine.

If your going to try tuning it yourself, an Exhaust Gas Temperature gauge (or Pyro) is needed to make sure you dont add too much fuel. It can be a fine line between more power and too much heat and engine damage