That looks pretty ideal.

 

That's great gate placement. One of the issues is you have to take into account the diameter of the valve VS the area of the diaphragm/chamber. 60mm is freekn huge! And that chamber isn't very large by comparison. So it will take less pressure to push that valve open than say a 44mm valve with the same size air chamber.

A 38mm gate in that location would likely give you all the control needed. YOu over gated that bad boy IMO! lol. With a gate that massive, even the slightest opening is going to vent exh pressure like crazy. I'd get some valve lapping compound and ensure that valve and seat are seated 100% Then add the large spring. It's a super simple design. It's either opening or it's not. Nothing should suddenly change on you. Setup the over-boost protection in the terminator and setup the AFR safety. You'll be fine!

 

is there a good way to tell if my wastegate is leaking .
when I have it on the car the intake will hold pressure.
but when I try put pressure into the bottom port with 19# spring , I can send the air hose up to 50psi and it sounds like the gate is just leaking somewhere.

ideally id like to put 14# gate spring and then maybe use some dome pressure to end up with 14psi

 

The bottom port will leak around the valve stem, that's normal.

The part that can't leak is the valve face and seat. Just like a valve not seating on a head. Basically hold your hand on the WG dump tube and have someone brake boost the car on the trans brake. If it melts your hand it's leaking! lol. But seriously tape a playing card over it or something. It shouldn't leak.

 

Had the car on the Dyno.
not sure on operator.
but made 430rwhp @11#

still seemed a bit low I thought.

is it worth setting up a gauge and measuring back pressure. ??

 

Something aint right for sure.

timing?
afr?
all cylinders firing?
spark plug heat range and gap?
what engine?

 

Ls 5.3 stock
btr stage 2 turbo
s480 80/87 1.25
ngk 7 heat range bcfe7 by memory
stock gap.
timing is 12* at 11#
tuner turned timing a touch down and leaned the Afr to 12 ish or 11.8.

 

I broke a piston at 11.7-11.8 at 12psi.

never heard of that plug. Maybe a b7efs? You need to check the gap. Where you getting any spark knock? Has the knock sponsor sensitivity been turned down? With a cam you could be picking up false knock. That will pull timing and kill power.

depending on compression, that timing may be too low. At 11-12lbs and 10.5:1 compression, I could only run 11 degrees timing. But now I have 9.4:1 compression and it will tolerate 13-14 degrees at 15-16psi. (5.3 btw).

After breaking a motor, and running at the track and seeing it didn’t pick up nothing going from 11.4:1 afr to 11.8:1, I set my afr in lowest boost to (1-7or8 psi) to 11.6:1 and then higher than that I go to 11.2:1 and when I get over 15-16psi I like it at 11.0:1 to 10.8:1

 

I am having no luck with anyone here , i can try work out basic things myself.
the tune was not set to go for max as we had some o2 issues and map sensor was a bit out .

i think ill get a sensor in the exhaust manifold and see exactly what backpressure is.
turbosmart said the backpressure opening the springs is not too uncommon , but i havent heard of it from any LS turbo guys here.

is 430rwhp @11 low or okay, im running a heavy dana60 detroit locker 35spline, 28" tire. Glide 3500rpm (if that helps work out the figure)
im not chasing big power or anything i just want everything to run well @ around 14psi .

 

Lot going on with your combo that could be sorted out depending on your goal(s) - whp, mph, driveability, etc. The clearer the goal, the more likely you'll be to achieve it.

Recommendation:
clearly define goal
goal typically leads to power requirement - full exhaust with multiple mufflers will likely impact this without a cutout.
power dictates fuel type (and amount) needed
power and weight determine mph
mph determines rear gear
vehicle weight, power and goal determine what trans is best - glide at 3800lb may be challenging.

Tune seems to be about 70 - 80whp short. I suspect it would wake up with 3-5* of timing. Reading the spark plugs will tell the story.

Yes, put in a back pressure sensor so you know what's going on with a full exhaust. Data allows you to make informed decisions.

 

street / weekend cruiser.
it has a full exhaust 3.5" all the way back with two mufflers on.
running e85 now anyway
car weighs 2800lb factory weight, thats with a 6 cyl , no big diff or v8 etc etc . im basing it off others , maybe 3500 -3600 lbs

the gears are nice to drive with now , evreything is sweet , not as gutsy as it was with the 4.1 but that was expected.

got car dyno tuned just to make sure tune was ok etc as i had just set it up and made some adjustments on the ecu myself .
the fact that the power was fairly low sorta through me as something is wrong, if eveyrhting is how it should be then im happy to leave it be , but was just curious .

was a 5.7 here on same dyno
stock motor stock cam just valve springs , not sure on turbo sorry . stock fuel . made 367rwkw 9#

just with mine having cam, e85 , more boost , to be running only 320rwkw 11#

correct me if im wrong , i dont really want to be wasting time and money finding a backpressure or cam timing or tune issue that isnt there

 

Didn't see half your reply sorry.

yep well I will get the back pressure sensor set up and get some readings.
once I do that I'll chuck in some more timing and see how we go.

 

With e85 you have some room to work with on tuning. How much timing did the tuner add before seeing power drop off? Did tuner read plugs? Are you well versed on reading spark plugs? I wouldn't "chuck in some timing" until you get a good plug reading. If you do add a degree or 2 of timing, how do you measure results? How will you know when to stop adding timing?

 

the tuner probably didnt run the timing until power dropped off.

my map sensor was not scaled correct , not sure why. its preset in the software and correct p/n
and my o2 sensor he said started reading a bit off.

but he was convinced that because we couldnt get boost to match the spring pressure , there was a backpressure or some issue so we stopped. also because of the sensors startingn to be an issue also.

haha yeah i sorta added a bit of timing and gave it some open rd b hammerings from start to high speed, but i wouldnt chuck anymore in than it has without a dyno.

 

What engine management system? What coils? Dwell setting? I'd always gap the plugs way down when things like this happen. It's easy/free,and rules out *most* ignition problems. With a questionable setup putting out low power, gap them to .015 to rule it out. Holley guys have a lot of issues with weak spark. Less so on the factory ECU's, MS3, etc. BUt no real reason to run a big gap when trouble shooting. Once it runs well open them up to .018 and make a pass. If all goes well continue opening them until you have spark issues. Then back it down .005 or so.

Yes, those numbers are low. Unfortunately there's a laundry list of reasons this could be. What converter are you using? Have you calculated slip? How much RPM are you turning?

I don't agree with your tuners strategy. You're running E85, which has a large tuning window for peak power. Why is he on the lean side of peak power? Fatten it back to to 11.0. Run it at a minimum of 15* at 10lbs. THen try 11.5 and see if it picks up power. If it doesn't, no reason to run it leaner. At that AFR and timing it should still be making over 20whp per pound easy... assuming everything was ironed out and working as it should.

All data is good! but unless you have a collapsed flex section or something really strange, back pressure shouldn't be an issue at 10lbs.

I'd be looking at major things... Converter, injectors all firing, check plugs after a WOT pull make sure they all read similar fueling wise and sprak wise. Address spark (gap down plugs), cam/valve timing (not ign timing). Boost leaks. Ensure throttle is opening 100%. Things like that.

good luck!

FWIW my 5.3 ran 10-11lbs. 15* at pk. TQ, ramp up to 17* by red line. Has a baby GM hot cam, so it will bleed less cyl pressure than your cam and would be more sensitive to detonation and higher timing values. Likely makes 20hp less NA as well I'd guess.The engine is non-intercooled and I'm only running around 65% ethanol. Plugs still look conservative. It made 540/600 on that tune up. I've since bumped the boost up to 19, dropped it down to 12* at Peak TQ and ramp to 15* by redline. Feels like it picked up another 200hp. it's a monster for a low buck street car. (twin 64mm gt35 china turbos).

All that said some dynos read high, some read low. May get it to a track and weight it and see what it traps. Does it "feel fast"?

 

My buddy had a 5.3 with stage 2 cam 76/78 turbo making 500rwhp at 9-10psi. I think your numbers are low. This is on 93 too.

 

checked all the exhaust , seems fine.
manifolds def had some decent leaks, fixed that up builds boost a lot earlier now , just while cruising , but on 100% throttle not much difference.
makes 14psi now with the eboost hooked up top and bottom. 19psi spring.

this was the table just running.
im gonna pull plugs later on , street car so not sure how much that will tell me.
i pulled 3 last time , were gapped at 25". its a **** job to get the rest , but ill get all 8 later.




just feels slow, and i doubt its any quicker than when it was on the dyno @ last power level.

 

cylinder #7

photo looks much worse than in real life.

???
rest of the plugs looking good , at least in the way of everything relatively even across the board and spark plugs firing.

 

The build up on that plug would likely promote misfire up in the shell. Also, looks like oil deposits more than fuel.