Tank said:Hey guys, I'm new to the site but have been around others for a while. With an intake and only a 70HP comp tune with a stock turbo what, if anything, can be done to raise boost pressure with the stock wastegate?
CPMac said:40+ psi will not hurt the stock turbo at all unless you plug the wastegate actuator line off. If you unhook or plug that line off I have seen them blow anywhere over 35.
socaldmax said:CPMac said:40+ psi will not hurt the stock turbo at all unless you plug the wastegate actuator line off. If you unhook or plug that line off I have seen them blow anywhere over 35.
I don't think I understand. Let's say one bleeds off boost and the turbo produces 35psi. How is that 35psi different from 35psi created from a turbo with a disconnected/blocked wastegate? I'm assuming both are measured at the same location in the intake.
Either way, the wastegate is not opening and the turbo is making more boost.
socaldmax said:"When the throttle is closed all the way with the WG disabled the exhaust energy is trying to spin the exhaust side of the turbo(without the saftey valve W/G), unfortunately (for me) the engine cannot ingest the air as the engine slows down. then you get a reverse pressure wave returning to the turbo stalling the compressor side.... "
Are you thinking of a throttle plate? There is no throttle to close. We step on a pedal which has a spring, 3 resistors and a couple of wires that send the signal to the ECM which controls fuel pump, fuel pressure, injectors, timing and pulse width. The intake tract is wide open all the time on a diesel. On the EGR equipped models there is a plate in the intake, but it is used to recirculate exhaust gasses, it's not connected to the throttle pedal.
If one disconnects the hose entirely from the WG, the WG sees no boost. Thus it never opens, never bleeds off exhaust and makes boost until equilibrium is reached between fuel, rpm and load.
If one cuts a hole in the hose, once again the WG doesn't see the boost (all or some of it) and if you're bleeding off enough for it to make 40psi, I think it's probably fully closed. Thus same scenario as above.
I've seen video of what you're talking about, "barking" a turbo. The engine was under tremendous load and the throttle was suddenly released. I can see how this can put huge loads on a turbo and damage it exactly as you describe. It just seems to me that the 40 psi, in combo with extreme engine loading (like sled pulling or stuck in the mud) and sudden throttle release are the real causes here. Not whether the boost is bled off or blocked off.
Maybe I'm missing something. Is there a way to make 40psi boost with a stock turbo without blocking or bleeding the WG hose?
Bronco said:This is really cool stuff guys! I have 2 questions for the both of you .
I was stuck in snow and spinning my tires a little. I was trying to rock the truck. I would put the brakes on and slow things down and then put it in reverse. The engine made some funky woofing/whirling noises. Do you think this was hurting my turbo? . It was -30 windchill and I was not about to be stuck.
What does a Banks Big Head Wastegate do?
Bronco, you have barked (surged) your turbo.... stop it
Most A/M wastegated are better quality designs to fight 'boost creep' under load to prevent crossing out of the compressors operating map and into the surge area. They also tend to be more aggressive in not opening prematurely and allowing peak boost to be built earlier and maintained. Most HP applications of remote wastegates are for high boost applications where adjustability on the fly is a requirement due to temperature increases/decreases and the resulting loss/gain in air density.
hoot said:Don't those pieces destroy the heads?. The pistons actually rise above the block about .015" with the only thing keeping them from smashing into the head is head gasket thickness.