HHR SS 2.0 LNF/LDK Big Turbo build with no bottom end power

Last summer I completed a big turbo build on my auto HHR SS:
LDK Motor with forged pistons and rods
supertech 94# dual springs and retainers
ZZP LHU Stage 2 cams
Opel Injectors
LT1 HPFP
ATI super damper
S257SXE Turbo
MVR Actuator
50mm BOV
ZZP Manual Boost Controller
Turbo Tech Racing Intake Manifold
3 bar map sensors
ZZP Intercooler and charge pipes
Custom made air intake that's 3" pipe to a 3.5" coupler to fit the 257sxe.

Car was remote tuned, then I dyne'ed with buddy Fonse Jr from Fonse Performance in NJ. We did all our pulls commanding 3rd in HPT.
Baseline at lowest boost setting was 241WHP, 280WTQ on 17psi. We fattened up the top end by .5 lambda to get it to 321WHP and 301WTQ on 17psi. Turing up to 22psi we made 339WHP 310WTQ. This is all on 93.

This past weekend I finally brought the car out to the track, and the car falls flat on its face out the gate before taking off like a rocket around the 330. Best run was 14.787 at 107.19. Car was running 4gallons of 93 and 5 gallons of VP MS109.


Curious to see if any tables can be adjusted to get more bottom end. The car is so slow at the start everyone at the track thought I had traction control on.

Attached is my Tune, the log from the last run, and time slip.

Attachment 100003

Your tune is WAY off base. You're commanding way too rich of a mixture at WOT. Your cam timing is also no bueno. Your DAL is off the charts, unnecessarily. Your injection timing is WAY off.

Brother, you need to find someone who understands this controller before you wind up tossing your built motor in the garbage.

Quote:

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Originally Posted by T-Man

Your tune is WAY off base. You're commanding way too rich of a mixture at WOT. Your cam timing is also no bueno. Your DAL is off the charts, unnecessarily. Your injection timing is WAY off.

Brother, you need to find someone who understands this controller before you wind up tossing your built motor in the garbage.

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That’s exactly what I did a couple weeks ago and they immediately ID’ed several issues - including the tune setup for stock MAF location, aggression with timing (which included an additional 2-4* at 7k) notice the MAL table out of whack, turbo spool was delayed based off dials/wgdc vs commanded, and fuel command pressure not being ramped. Oh and MAF and Fuel rail codes were disabled.

Definitely making progress - car feels smoother, and if any KR appears it’s under 2* regardless of boost setting, mainly from cyl4 and sometimes under 1* from cyl1. I know I can help correct that with the retard hysto after watching the CBSSOB vids.

Car feels more responsive 2k and up when rolling, but still absolutely nothing from a dead stop still.

Welcome to the world of a poorly selected turbo size for the engine. One friend of mines Cobalt SS that I tuned went through a few iterations.

He started with E47 on the stock turbo. We abused the hell out of that turbo, gobs of low end tq, really fun to drive. If I remember it pulled a low 13 at rougly 113 or 114mph. I believe we put down 365whp and low 400 wtq (if I get motivated enough I will look up the dyno sheets if I still have them anywhere). Fully spooled by 3k, lots of fun easy to launch and not bog/pedal to avoid blowing the tires off.

He wanted to go faster, so he put on the ZZP kit with the S256 extended tip turbo. We switched to race gas to run for fun on the street and track because e85 is impossible to find in our area (Toronto), and to get e85 we would have to cross the border into NY. Put down roughly 450whp and low 400wtq. The thing is this turbo doesnt hit 20psi until after 3600rpm, it bogs off the line, and then rips the tires loose on spool. If you pedal it, or miss a NLS you fall out of boost and are lagging again. (running 26psi at this point)

Couldn't beat a low 13 again, but he is now trapping 120mph. He wants to go faster. I suggest getting rims and slicks so he can actually use the power he has at the track. Nope he wants power upgrades the turbo to an S258.

We push this thing up to roughly 550whp and I believe it was 440wtq range. Spool is even worse now, I think we dont hit 25psi until 4.2k. But man does this thing move once you get it up there and stay in it. I describe driving it on the dragstrip like this:

Launch, you either bog, or rip the tires off. If you bog, it spools, rips the tires off, and you are at 8k. Grab 2nd, bog finally spools rips the tires loose. NLS into 3, holy hell you better have a tight grip on the steering well as the tq steer is insane!
Grab a NLS into 4th, and fly through the traps at a best of 12.8something at 126mph! Guys at the ticket window snicker and ask if you like the 2nd half of the track.

This was all on a stock engine, we abused the hell out of it for a few years and never had an issue with it. Transmissions were a different story. 3rd popped on the dyno once on a run. He killed the second transmission on the street one time during a pull. Upgraded to a 4.45 and never blew it up.

Once you get the tune sorted out on your setup it can be much better. You will never have the low end you seem to want with that turbo, thats life. What you can have is amazing top end power. To do that you need to crank up the boost. You need to make up for your low end lag by either having slicks that you can launch under boost (not sure how the auto would handle it, I only ever worked on one automatic HHR and it had a stock turbo), or having insane top end.

Switch back to E47 or E85, and run 28 or 30 PSI.

If I could find my old dyno sheets I remember the first upgraded turbo I tuned on a cobalt was probably similarly sized to an s256, he brought it to me tuned by another tuner in the states all happy because his dyno sheet said 400whp, on only 18psi. Slapped it on the dyno with no changes and it slapped down an amazing 300whp. At this point I had a couple of stock turbo cobalts running 310whp, plus way more tq. Overlayed the dynos and showed him he was slower then a tuned stock turbo.

You need to run big boost to make god power on the upgraded turbos. Think 26 as a starting point, especially on a built engine.

But with the setup you have, just know there will always be this low end lag, short of using a small shot of nitrous to get the turbo spooled.

If you want more help tuning this you will need to post your tune and log files of the current tune.

Appreciate the info! Current tuner is different than OG tuner, who is getting decent progress with this. We’re remote tuning since I’m in the northeast and he’s down south.

He recommended e47 as well, after we tried ms109, and he said he wasn’t liking the response he was getting from it.

You’re 100% right about bog at the gate - when we tracked the car that’s exactly what it did. Bog until 330 mark then a completely different car 2nd half of the track. Current tuner wants the car at 29psi, which we couldn’t hit with the old manual boost controller. New controller gets us there, so now it’s time to get the car dialed in on 93 before we switch to e47 as a track tune. He even suggested looking for a .48 AR to get the turbo to spool a bit quicker compared to the current .63

Honestly I’m okay with a little lag - but original post was straight lag until after the 330. I even roll raced a friend who’s k04r full built on E85 with his auto HHR, and we’re talking 3-4 tractor trailer lengths between us by the time mine woke up. Bad, bad, bad. I know these auto HHR’s have an awful 60’ time, but if I can get it to wake up before the 330 rather than after - that can help a bit.

I’m running radials on the track, still couldn’t get it to launch. Even ESC off I can’t get the car past 2100 brake boosting, so no way tires are breaking loose.