Drift-Office : AVO Turbo Kit Stage 1 ~ 91 Octane Calibration
 

[ame="http://www.youtube.com/watch?v=b66r7iTQsNI"]Drift-Office : AVO TurboWorld 6MT FRS / BRZ / GT86 Turbo Kit ~ 91 Octane Stage 1 Tune - YouTube[/ame]



So we had a customer who drove in from Montana to get the 5th production kit installed and tuned here in the US. With that, came a technical challenge - we were under the gun to get the project completed so that he could make the trip here and back within 5 days but more so, tune with the 91 octane gas that he brought along.

There were certainly some challenges to work with in terms of fuel limitations but we were successful in overcoming them. I was quite surprised to see how much difference a single octane made and after a quick line of questioning, we discovered that the fuel purchased was made from a 3rd tier gas station. Read : that means gas quality while "91" might not have been as fresh, much less real "91" octane...

The car had been equipped with 18 inch Sparco wheels and a full Milltek exhaust system (Over / Front / Catback) @ 2.5 inches.

Here are the results in both SAE and STD formats :

http://i22.photobucket.com/albums/b3...ps2f7a516f.jpg

http://i22.photobucket.com/albums/b3...ps6b9b0e7b.jpg


The components and tuning handled it very well @ the Stage 1 / 5 PSI level. Assuming that the fuel in CA and elsewhere would be fresher and of better quality, I would say that it wouldn't be a stretch to achieve better numbers. We had initially planned on doing a Stage 1.5 or 2.0 with this, but the customer's clutch gave out @ 212#s (driving style) @ 8PSI so we'll have to try the higher boost some other day...

So for all you guys in CA, this would be pretty indicative of what you're looking at. :) More on this as the situation develops!

FYI,


Bob @ Drift-Office, LLC

But Bob, this is a turbo kit! There's no way it can hold power to redline!

[/sarcasm]

That's a sexy torque curve.

Very nice! I can't wait to get my build started.

Thanks Bob! Keep us Cali guys posted!

Bob- is there a boost creep problem with these kits? Or is that boost curve calibrated with an EBC?

Boost creep has never been a problem with any of our 92 Octane tunes with the AVO kit. I think given FRESH 91 Octane fuel from a first tier company would make quite a bit of difference here.

Truthfully, the problem is that of the fuel. At that octane (bad 91,) there's a very fine balance between ignition timing and fueling; do we add more timing to the calibration to lower EGTs so that we won't get boost creep and risk knock subsequently or do we back off timing and let boost creep up a little while ensuring everything else is safe? The timing that's in there isn't retarded by any means, nor will it burn up any valves - and AFRs have been made slightly richer globally.

It's an extremely delicate balance here and the tuning strategy we've adopted once again is of safety and preservation. It's hard enough to get 91 octane that to run a HC DI motor, much less a boosted one. All things considered, it's marginal considering that the actuator is 5 PSI and we're only seeing a little more than that. :)

Moreover, the gas purchased here is suspect in that it was bought on a military base. We reckon this is closer to 89 Octane (and I'm not suggesting that we try running that!) as it's been sitting for a bit and it's a compromise, but given those conditions, I think we did quite well!

My 2 cents!


Bob @ Drift-Office, LLC

It should also be noted that further R&D into (fresher) 91 Octane is scheduled, expect to see additional information on this page when we have an updated calibration in the coming weeks.

Cheers!


Bob @ Drift-Office, LLC

Thanks Bob, that's very interesting. I've not seen that effect of EGT's affecting boost levels before. Most of my stuff has been 1-2 bar though so perhaps its not so obvious.

I doubt that you're using low grade 91 Octane fuel either. :) Certainly, you don't see it in our Stage 1 / 1.5 / 2.0 tunes using 92 octane. It could very well just be bad / low quality gas that's used in this customer's car.

Like I said, it was pretty suspect and I feel that this was a happy medium. As mentioned, there will be further testing in the near future. 91, 92, 93 (Ethanol FREE!) and 94 are all going to be used on the AVO kit when I get mine installed...

Cheers!


Bob @ Drift-Office, LLC

good lookin curves!

Bob, can you post the dyno with the smoothing set to 1 or 0 so we can see if any ECU correction is going on?

I have to commend @Drift-Office getting the power out of it that he did - that was pretty bad gas. Unfortunately, this is some of the issues that people owning these cars will deal with across the United States. I'd be the first to say that, N/A or FI, don't run these cars on Arco or other "cheap" gas (Costco is just fine, though).

The customer noted that he seldom got more than 240-250 miles on the base gas in his area, but when he filled up at the regular gas stations, he'd go 300 miles. That tells me the car had been pulling a lot of timing on the bad gas.

When we were doing the testing in California, we almost exclusively used Shell or Chevron 91 octane. Once, however, I filled it up at a Texaco, and immediately we had to pull a couple of degrees of timing out. It was seriously that bad. Unfortunately, I don't know with absolute confidence if they are all like that, or that particular one was pulling the "put 89 in the 91 pumps" trick to make some extra cash.

There wasn't any timing being pulled in this case, but looking at the logs, you could see that the multiplier wasn't taking it in fully. It would drop ever so slightly and that told us that we're already at the limits given the fuel we had in that car...

Cheers!


Bob @ Drift-Office, LLC

Not that it matters because no one is going to run boost lower than 5 psi but this data combined with vubarus hints that the wastegate flow is maxed out at 5psi and you would t be able to go lower in boost. Since its at its max flow having higher egts is not compensated for by the gate.

I would expect even with crap gas that at higher boost levels where the wastegate doesn't have to flow as much you won't be seeing this irregular boost problem. A properly size gate is supposed to be able to control boost at ease regardless of timing n egts. It senses pressure in the charge side and adjusts the vent to hold that.

Maybe the base kit should be using 6-7 psi instead to avoid this issue? Thoughts?