Twin Turbo stroked cammed LS3 not making power

Ok, this is a 416 10:1 cr, cam is a custom 233/248 .629/.600 115 +3 LSA, ported ls3 heads by tsp, the turbo kit is a AGP twin turbo kit with twin 5858 comp oil-less turbos and the big intercooler, AEM water/meth kit on 100% M1, boost controller is the GFB3, all going thru a built 6l80 with a circle d 3200 triple disc converter and a 3.70 gear. I was expecting to make near the 900whp on this combo but it wouldn't even break 700whp last dyno pass was 670whp, the car idles and drives perfect no missfires or noticeable stumbles and part throttle feels really good.

Since this is my first turbo tune i would like to see if there is something obviously wrong in my tune to be so low on power.
this was on 100 octane gasoline
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The MAF stopped working while i was doing the SD tuning and i haven't fixed it but at this point i feel it shouldn't affect power.

It could be losing some power up top with how rich it was. You are almost touching a 10.0 AFR above 6,000rpm. The commanded to actual AFR is pretty far off there.

Possible that your camshaft choice isn't the best for your application but I'm not a camshaft wizard.

I feel like at that boost i should be talking about atleast 100 more horsepower

You need to log the other timing PIDs and fix your fueling issue. At 15 PSI you should be able to get 15 degrees on 91 and 18 on 93 without the meth. 825hp is the best you can get on 91 even on a ls9/lsa block with oil squirters for the pistons. 825 with meth an no squirters maybe. As 5FDP stated it is too rich. Lambda 0.782 / 1.278 pe value should give you what you want when you fix the fueling commanded-to-actual issue.

Aand we torched it!

Looking for more power on the dyno we gave it a little more timing an leaned it out some, took it down the track and on the second pass the car sounded weird so i let off the throttle, it was making a sound a lot like when you have a bad header gasket, only much louder, oil pressure is good, radiator water looks clean but its seeping out of the engine from the passenger side where the head meets the block on cylinder 4, we will be taking the heads off the engine later today.

So lets got thru some important facts, the engine is a TSP 416, custom turbo cam 233/248 .629/.600 115 +3 LSA, ported LS3 heads, on a AGP turbo kit with twin Comp oilless 5858 turbos, backed by a 6l80 with a PATC stage 5 kit, circle D 3200rpm triple disc converter, it had a 3.73 rear end and we used 26" tall drag radials at the track, all that was fed thru a fore triple pump system and FIC 1300 injectors this was on VP Racing C85 and a AEM water/meth kit running 100% meth.

We where expecting close to 1000whp out of this combo but barelly got to break the 700whp mark, this being my first turbo car and with the owners pressure i started second guessing myself, i gave it more timing and over corrected for the rich condition up top, on the dyno the car responded very well, it made 40WHP more in the entire graph, put a new sparkplug gave it a dyno pass, took it out and it looked clean as new, the electrode changed colors to a whitish stuff all the way to the base, that should have been a sign right there but with the owner of the car still pressuring me to make more power i decided to leave it there instead of taking it back to a richer tune with less timing.

The track rental came, and the OBD2 port on the AEM wideband stopped working, i could log the car but it wouldnt detect the wideband, still the readings on the wideband looked inline with the O2 and i decided to go on, gave it first pass and the shiftpoints where too high (this car used to have a NA combo) i let out around the 1000ft mark thinking i should have had good 1/8 mile data, but something happened with the timing system and the only thing i got was a 1.9 60ft. Still i dataloged the pass, and paid close attention to the wideband it was between 11.8 and 12.2 for the complete pass.

Gave the car 45 minutes to cool down, corrected the shift points, and as i was going down the lanes my laptop battery died, so no datalog on this pass, on take off i felt the car slam the rear end on the ground and as it shifted to 2nd gear the engine sound changed so i let off, afr where again 11.8 to 12.2 at WOT and after i let off went to 14.5-15 while cruising back to the pits, oil pressure was good, water temp Looked good but there was the weird noise coming from the engine when i stopped there was some water coming out of the engine and i tough maybe i had ripped something off the exhaust and turbos when the rear end slammed on the ground and pinched the exhaust between the floor and the car.

The car will cold start and idle, AFR readings and O2 corrections still look good, there is no hesitation when accelerating, just the water and the loud failed exhaust gasket like sound.

So im leaving all this for any future tuner or enthusiast looking for info, dont second guess yourself, dont let pressure cloud your judgment, dont rush things and stop if things are not lining up as mistakes like this are very expensive.

Here is the datalog from the first pass, as its the only one i had from that day AFRs where between 11.8 and 12.2 the whole pass and it was aborted around the 1000ft mark.
Attachment 104875

Tonight i will try and upload some pictures of the carnage.

If you get lucky, all of the damage will be on top of the head gasket (and a torched head to the jacket). You will find that spraying methanol opens up the WOT window a good bit... Whereas without it, you may make best power in middle 11's AFR, but WITH IT, you can make the same power around 11.2 that you do in the mid/upper 11s and this is where you want to be with a combo like that. I think the poster above you is talking about timing in a very absolute way and I always avoid that... there's no way I'd send some guys 10+:1 418 out on 15 PSI at "and 18 [deg] on 93 without the meth" as he says. Maybe he's talking about LSA's or is at high altitude; I'm not sure. But I have tuned flat-top 418s with milled heads that don't want more than 20deg around peak torque... and they are N/A!

That log looks scary... Notice up top how it actually LOSES RPM several times approaching shift. Try and get your turbo cars to shift EARLY and THEN move them up. Back pressure gets nuts up top if things are over spun. You had it on the dyno, so you know where it lays over. In the log, the narrowbands suggest it's quite lean there in first gear as boost ramps, and that spot coincides with the knock you see there. Bank1 has some issue going into third gear (see NB voltage). High gear has so much hard knock that delivered timing is NEGATIVE through the gear, pulling over 12 deg in some places.

I mean this very nicely but I don't think it was track-ready.

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Originally Posted by Frost

If you get lucky, all of the damage will be on top of the head gasket (and a torched head to the jacket). You will find that spraying methanol opens up the WOT window a good bit... Whereas without it, you may make best power in middle 11's AFR, but WITH IT, you can make the same power around 11.2 that you do in the mid/upper 11s and this is where you want to be with a combo like that. I think the poster above you is talking about timing in a very absolute way and I always avoid that... there's no way I'd send some guys 10+:1 418 out on 15 PSI at "and 18 [deg] on 93 without the meth" as he says. Maybe he's talking about LSA's or is at high altitude; I'm not sure. But I have tuned flat-top 418s with milled heads that don't want more than 20deg around peak torque... and they are N/A!

That log looks scary... Notice up top how it actually LOSES RPM several times approaching shift. Try and get your turbo cars to shift EARLY and THEN move them up. Back pressure gets nuts up top if things are over spun. You had it on the dyno, so you know where it lays over. In the log, the narrowbands suggest it's quite lean there in first gear as boost ramps, and that spot coincides with the knock you see there. Bank1 has some issue going into third gear (see NB voltage). High gear has so much hard knock that delivered timing is NEGATIVE through the gear, pulling over 12 deg in some places.

I mean this very nicely but I don't think it was track-ready.

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Yes as i stated before this pass the transmission had the shiftpoints set too high, on the pass that broke i corrected it and shifted at 6000 rpm, on the dyno it went 10.0 on the boost ramp and on the track i didnt have time to check it. I hadnt looked at the NB voltage before, but on the log from the dyno on the first post the voltage from bank 1 and bank 2 are very different, shouldnt they be more similar?

as promised the pictures after taking the heads off, plugs are not in order, the melted one comes from the torched cyl #4
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Head gasket, the block will need minor filling
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The heads i wont reuse
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Ahh that sucks... did it hurt the top of the cylinder liner?

That's a stock heat range plug and it's a HUGE no-no. NGK 3346 / BR7EF is what I'd use for that. It's 2 steps colder and non-projected. They are 0.027" out of the box. Those OEM range TR55's are like .050-something out of the box and you have to nearly curl them to close the gap that far.

Key points:
Wrong plugs for boost
High IAT
Aggressive timing
Lean AFR (maybe from ltft) or from not checking after dyno

Frost - Does the LTFT carry over on these ecus? its showing -5% for bank 2

Quote:

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Originally Posted by 240sxpooter

Key points:
Wrong plugs for boost
High IAT
Aggressive timing
Lean AFR (maybe from ltft) or from not checking after dyno

Frost - Does the LTFT carry over on these ecus? its showing -5% for bank 2

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As far as i know only positive fuel trims affect WOT

Quote:

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Originally Posted by mJolnir

As far as i know only positive fuel trims affect WOT

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Correct.

Quote:

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Originally Posted by Pekka_Perkeles

Correct.

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Thanks for the heads up!