Just curious if anyone has tried this.

With my motor recently refreshed with new rings and bearings, and a new 24x efi conversion installed, i wanted to attempt breaking in the motor without boost for once, or atleast as low boost as possible.

I need to make sure my wiring harness works and the efi system works with this cam sensor, crank sensor, and ls1 ecm etc. rather do that without boost but i have broken in both new combos with boost before so maybe this isnt a big deal.

I want to gut the wastegate, take out the spring and valve if possible to force it open or find a very soft spring to make it basically open immediately. I was gonna fab a bypass from the turbo but decided not to due to time involved. Trying to get it runing before years end.

Just curious if anyone had tried this and how much if any boost reduction they saw?

System is a twin setup, with one 40mm gate per bank, 90 deg off feed pipe. With supplied 6-7 psi spring, it holds 6 psi all day long so it seems to work fine. No creep issues like my last design.

 

I did it for the initial tuning. With the actuator rod disconnected from the internal WG it would boost to 4 - 5 psi. This allowed me to get to the higher RPM areas without the boost coming in too quickly.

Then once the VE tables were good, hooked it back up and tuned in the boost fuel tables.

RBob.

 

What was normal boost on wastegate?

Thats basically my plan, i have new ls1 0411 pcm and need to work a base tune and would like to hit all areas of high rpm no to low boost as possible. I already have an idea what it likes for timing, just not as much for wot before spool. It rarely if ever sees more than 4500 rpm and kpa less than 110, so those areas would receive attention with gate disconnected lol

My new converter stall will likely put me on top of my boost threshold so this may be a pointless exercise but its more for curiousity sake

 

Just leave them hooked up and use a lil as throttle as possible. This will keep boost down and u can tune fuel and spark lil by lil giving it a lil more throttle each time.

That's how I've always done it

 

Thats how i did it before lol just curious if there was an easier way to do more all motor tuning for break in than using boost so soon but oh well. Once you hit main cells for operation, you start to see the fuel curve and can easily scale it out from there. Hope hp tuners uses 3d graphs like tunerpro

 

24+ psi. The turbo spools so quickly that it is difficult to modulate the go-pedal to stay out of boost. Once the RPM starts moving up the boost is there.

Disconnecting the WG rod prevented the fast spooling and made it much easier to keep the boost away.

RBob.

 

Good to hear. Thats what i was hoping would happen and i may just try it

 

Spring from starter bendix solenoid = immediate opening, that is what I used...

 

I just said screw it, left gates on with springs and had car fired up few weeks back. had to do some minor adjustments to valvetrain and took it for a run on a base file my friend did for me, based on our buddy's 370" lsx single GT42 motor. I dont have HP tuners and dont plan on buying it for 650 anytime soon, especially since winter is here now and I'll never get it to any tracks anytime soon.
Motor runs pretty good for a base file. Few rough spots in cruise that need worked out but closed loop is running dual o2's well enough. Slowly worked into WOT and it hit 6 psi, took it through 1st to near 6K rpm and shifted second. Converter feels a tad looser than before which really helps spool and new tranny is shifting nicely.

So all its well and my car is ready to really tune up. Hoping to do some street driving this weekend to get it driving better and slowly work into the Boost tune. No idea what he has for timing but its abit rich, mid 11's at 6 psi. Before I ran closer to 12.0 and 30-ish deg timing Aggressive but it kinda liked it.

 

Yes! I've done this. I always recommend this when tuning an engine! This is a greatly under appreciated idea. You can tune a turbocharged engine at wide open throttle as if it was "more naturally aspirated" without the additional risk of making any real power associated with boost. That will give you the VE curve of the engine! Now your fuel requirements are plug and play for any boost level, AND you can get a feel for how much timing she prefers.

Always Smooth: 0

 

Yeah that was the goal and i still may pull springs lol but 6 psi is pretty low as is and base tune is close enough that it shouldnt matter