I'm out...
 

So I have to out myself. I went the ecu tune route. No dis to Race Chip, (its in the interest of science). To be expected once I got the Red Ryder bb gun (aka HP tuner VC Suite), I did get a good glance off the side of the head with an errant bb. Almost shot my eye out, but I'm ok.

I logged a very robust 335/350 hp/trq which is pretty amazing to me. Car is definitely quick. I havent any ETs to post yet. (Elllioottt) I am on a movie reference jag right now if you havent noticed.

So, I do have some interesting info to share coming up. My exhaust mods. I replaced my stock exhaust with the added mid pipe resonator for the Borla 'touring' exhaust. A big swing in restriction levels.

Along the way I only did the Sport exhaust without the resonator first. It was loud. BUT the topic I am chasing down is that I lost a lot of power, like 10 percent hp and torque (30-35). All things remaining equal, with just the rear jugs on.

I put the mid pipe resonator back in and I am in the Goldilocks zone, tone is good power is better than before, but no logs yet. The Borla S kit with the resonator constitutes the 'Touring' version.

Other than finger wagging and nodding heads who has any ideas why?

I have my ideas- but I wanted to see what if anyone knows before I put up my info./
This is for extra credit, I wasn't lean lamba was good, maybe just a tad lean. Fuel trims were near nominal.

Looking forward to seeing the direct comparisons between your legit tune and the RaceChip. If you can keep as much of the other pieces similar so that the comparison is as accurate as possible, that'd be cool.

A proper tune is probably in the cards for me next spring/summer, which is annoying because I went with the catted DP, but oh well. RaceChip did give me the GTS for free because of all of the issues/delays I dealt with, so I don't feel bound to it.

Don't mean to hijack the post but any time you wanna sell the CATTED DP, hit me up.

Odds are it'll stay in due to pure laziness (it was not an easy job for me without a lift or anything like that). But if I decide to go catless when I get a tune, I'll post it for sale.

to clarify, its not the DP.

Perf exhaust on: definitely less restrictive esp w/DP.

with resonator on - power back to normal (looking for better than the start of all this).
with resonator off - lack of power.

hint: think spool rate.

Sounds like there may be a few racechips for sale soon.

There is zero difference in HP/TQ between catted and catless down pipes. Catted sounds better and has less exhaust smell.

Its a good stepping stone and a good easy performance boost for many. no regrets for the time I used it and the knowledge I gained while getting the facts confused with who is the least best tuner out there.

Seriously, who buys an ltg for the purpose of making it a dedicated drag car? I say if your happy with your RaceChip then its a good way to go.

A80 is still a bit of an emigma (as far as my observations within HPT). It is not a bad idea to wait until the collective knowledge base and expereince with it "matures" some more.

Well that's fantastic information.

here's my theory of it. clearly all remained equal. There is one weakness in HPT up to the current release and its the wastegate PID. Aint none. I mentioned in another post that the engine ecu also has predictive responses for self protection. I qualify this that I am just a novice but, pretty astute and I won't put my self out there w/o at least some logic that seems to hold water.

https://en.wikipedia.org/wiki/Boost_controller

"The basic algorithm sometimes involves the EMS (engine management system) "learning" how quickly the turbocharger can spool and how quickly the boost pressure increases..." blah blah....

"Stepper motors allow fine control of airflow based on position and speed of the motor, but may have low total airflow capability. Some systems use a solenoid in conjunction with a stepper motor, with the stepper motor allowing fine control and the solenoid coarse control." etc...etc...

"Since less positive pressure can be present at the wastegate actuator as desired boost is approached the wastegate remains closer to a completely closed state. This keeps exhaust gas routed through the turbine and increases energy transferred to the wheels of the turbocharger." Ok OK OK...

TADA!-

"As overboost reaches the programmable maximum, the EMS begins to decrease the bleed rate through the control solenoid to raise boost pressure as seen at the wastegate actuator diaphragm so the wastegate opens enough to limit boost to the maximum configured level of over-boost."

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I believe the ECU also measures (or Calculates) spool rate. if it clocked over the limit in the ecu, then the ecu was keeping the wastegate open. I see this with the lower cylinder air mass in the logs. Overboost (spool rate) was triggering the wastegate since the turbine was faster than allowed with the free flowing exhaust. Also I could tell just by listening that there was no really good turbo "sound".

Now with just a little extra back pressure it came back to normal power, good spool, whine, power, BOL woosh.

By ONLY adding a straight pipe muffler before the Y pipe, in the tunnel.

Refute, Rebut and Reject as you will. But I was There!

I guess the only logical thing to do is jail break overboost protection, but this marks my stopping point.

Also keep in mind this was with a tuned ECU that is already demanding torque and thus boost at higher levels. So untuned ECUs probably still have a higher margin for overboost and so they would/may not see this issue. Unless some one tried straight pipes. ?


Anyways that's my essay.

W./

here's the picture - I am off now to logging and collecting my histogram for new fuel calcs. I get extra credit for this.


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