fleming23

I went by my buddy's speed shop this morning to check on the status of another car I have there getting tuned. While I was there I decided I wanted to put the Z06 on the dyno to check air/fuel after installing the 2017 supercharger lid as well as see what sort of power levels I was at, now that I have had the Halltech RZ intake with nomex sock installed since before the summer.

The results are below and speak for themselves. Yes, the car is making more power but the air fuel is lean to the point I am not comfortable tracking the car in this configuration unless I want to tune it. I will remove the Halltech intake and go back to stock, while keeping the 2017 lid. 13+ air/fuel is not ideal for a supercharged motor in the meat of the power band and as I track my car rather heavily, I'd rather see that go back to stock mid 12 levels.

I may hang onto the intake and tune the car once my warranty expires but at this point I believe the intake is definitely coming off.

Only modifications to my car
2017 supercharger lid
Halltech RZ stinger intake with Nomex sock
Corsa Double Helix X Pipe
Magnaflow competition axle back exhaust




This is an overlay from the April 6th dyno pull, when the car only had a Corsa x pipe, to today.

fleming23

Tried to make the dyno graph larger but I guess photobucket won't go bigger than 1024.

Here is another comparison showing hp/torque/air fuel

demasterz

I know it's not relevant to your thread but which side markers are these?

C7/Z06 Man

Looks like the "stock" torque/hp was pretty even with the Halltech/lid/exhaust up to approx. 5000 rpm than the fuel went way rich due to COT on the stocker but not as bad for the Halltech/lid/exhaust mod. Also below the 5000 rpm 12.5 afr makes approx. the same power as the leaner 13+ ratio.

It also looks like that when the stock afr hit approx. 12.2 afr is when the leaner mod. afr started to pull away.

fleming23

Those are from Showstoppers. Same guy that did my valve covers.

ajrothm

Interesting results for sure... The 15hp gain with the addition of the Halltech kind of mirrors the MPH gain that mine had at the track..(1 mph-ish).

Yours is a bit lean in the midrange but, I don't think I would be overly concerned with it, if you weren't tracking the car but...Running it hard in the midrange the way you will be, its not worth the risk IMOP. I'd put the stock intake back on as well, or the stock lid back on.

Either way the car makes good power.

0Terry@BMS

I'm working on a better drop in filter option for us.

ACS55

WOW...

This really makes me rethink my plans to buy a 2017 lid.
I was mainly going to buy the lid (and have it powder coated red) for looks.

There is no way in hell I am taking off my HT-CAI, unless its a temporary trip to the dealer. The CAI gained me .22 ET and 5.3MPH in the 1/4.

Did you do a run with the stock Air Cleaner and WITH the 2017 lid to see if the lid is really responsible for leaning out the AFR? My AFR leaned out ONE FULL POINT as a result of the HT-CAI.

Attached is a pic of my dyno run after adding the HT-CAI, showing a 12.5 +/- AFR pretty steady until the COT begins kicking in around 4800rpm, and steadily leans it out to 11.1 AFR by 5700, then it stays pretty steady from there on up at 11.1 AFR. I am pretty satisfied with this AFR and do not want it leaner.




(my car is a stock 2016 C7Z A8 with only a HT-CAI, with Torco & 93, and was dyno'd with my track wheels/tires)

fleming23

I did not, was never my intent although it would be really simple to do. If I only did 1/2 or 1/4 mile racing I would not be worried but for the prolonged road course use my car gets, it isn't worth the risk. I was just discussing this with another car friend, a replacement LT4 isn't really all that expensive (relatively). Might get the car tuned instead of removing the intake.... We'll see.

ACS55

My "before CAI" AFR graph was shaped the same, except 1 point richer across the board... Just imagine what a 10.1:1 AFR does for power at the top end! 11.1 is not good, but 10.1 is even worse.

WTH, i will just post the graph and you can look at it.
(My point is that if your stock AFR is comparable to what mine was

, you will be losing a lot of power comparably. If you're going to keep the stock tune, maybe sell the 2017 lid and keep the CAI??!?!!?!?!?!?)

Here is my Dyno from:<br/>Before CAI<br/>No Torco<br/>Stock Wheels & Tires

fleming23

I posted my pre-CAI dyno, it picked up approximately 15 whp between the two pulls, and most of that was 5500 and up. If the middle of the curve was significantly different, it would matter more to me but that area is nearly identical. . I'm not overly concerned about that little power to one maintain my warranty currently and two, go back to a safe air/fuel. I'm still undecided which direction I will go, but it won't stay like this, that I assure you.

Halltech

Unfortunately, no one that runs a dyno has updated their software to the current e10 fuel, which has a Lambda 1.00 of 14.1:1. Quoting air fuel ratios with e10 fuel which has 3.5% oxygen in the fuel is misleading unless one uses the conversion factor that the DynoJet is not factoring in.

Dynojet software uses 14.7:1 air fuel ratio to determine Lambda 1.00. If the fuel has oxygen in it as does e10 (3.5%), then you must factor in .959, which brings a 13:1 air fuel ratio down to 12.5:1.

12.5:1 is safe for full boost levels on a direct injection motor. The perfect stoichiometric burn (Lambda 1.00) for the LT4 is 14.1:1 air fuel ratio running e10, 9.85:1 with e85, and 14.7:1 on e0 or pure gasoline.

In other words, your engine is running 14.1:1 during closed loop ALL THE TIME, until your get the throttle into max position. When you trip into open loop (fuel enrichment mode) the ECU adds injector pulse width or duration to prevent spark knock, and in the case of a direct injection engine, less fuel is required to accomplish knock attenuation.

Notice that the Cat Over Temp Protection circuit kicks in around 4200 rpm, adding more and more fuel, to prevent the cats from bricking.

We have had track testing by Andy Pilgrim and other racers test our intake with stellar results. GM tested our intake system back in 2014 at the GM Proving Grounds, and referred our system to their Specialty Vehicle Program. They would not do that if our intake caused issues when racing.

When we came out with the TRIC, we expected the possibility of a lean condition, especially with the 2.7PSI increase in boost, but we had no knock retard, full 25 degrees timing, and IATs within 4 degrees of ambient at 88 mph, 125 mph, and 144 mph.



We now have a full two years of long term testing on our Z06, under all conditions, and 8700 miles. The log above was done at 8500 miles on our Stinger-RZ, and three track events. We have sold over 1100 Stinger-RZs, with over 75% of those to our installation shops, engine builders, specialty services, including dozens of dyno tests that show the same 12.5-12.6:1 air fuel ratio on e10.
Jim Hall

fleming23

Thanks Jim, that difference was certainly something I had not considered in reading my data. I did experience a good bit of knock on the dyno, up to 5 at a number of points. My post was not to point fingers at the Halltech intake, although I suppose it indirectly does that, but to show what sort of air fuel readings I am seeing with the current configuration. I ran your intake all summer at various tracks with no obvious issues, and hopefully not creating any less perceptible future issues.

ajrothm

I experience a good bit of KR with my car as well with the Halltech. However this could have happened as well with the stock intake. If you look at the ECT vs Timing table on the stock tune, it starts pulling timing as early as 194*...which is your normal run temp. My car was hitting 212* going down the drag strip and you can see the KR in this graph:


I haven't investigated it yet to see if with was ECT causing the KR (it very well could be after looking at the ECT vs Timing multiplier) or caused from real knock but...It definitely has some. 2-5* in some places.

0Terry@BMS

Couple of random thoughts:

1) If using the factory flash you'll always have "KR" reported below 4500rpm as its mapped out in the flash map to pull from cyl1 for some reason.
2) Lambda readings on a dyno wideband reflect an accurate air/fuel ratio regardless of the ethanol mix being used.
3) The wild fluctuations in intake AFR are partially caused by changing the maf housing size and variance from unit to unit when rotomolding. Another factory is overly aggressive WOT tuning which confuses the issue when trying to evaluate on the dyno. Varying levels of turbulence through modified maf housings also can cause some inconsistent results.

Higgs Boson

The Knock Retard pid only shows activity from the knock sensors, it does not show timing pull from other sources. If you log Total Knock Retard pid you will see random timing retard events and can log all the other retard sources to see where it's coming from.

ajrothm, this means the KR in your chart is real knock.

Terry, cyl specific pull won't show up under KR, only TKR.
also, you are correct that the AFR read on the dyno is correct if you look at AFR "in a vacuum." But when you consider that everyone bases a relative AFR on E0 at 14.7 then it is better to think in terms of lambda because 11.5:1 on E0 and E10 is not the same thing when it comes to Stoichiometry and a percentage of enrichment. People think they are richer than they really are which is a mistake. If you are running 12.5 on E10 on the dyno but you are thinking in terms of E0 at 14.7 then you are really running a lambda equivalent of 13.03 AFR, which is too lean.

Always think lambda. Everyone should erase AFR from their minds. AFR was great when there was only one fuel to think about and ethanol was still food for Iowans and alcohol was reserved for moonshiners and funny cars.

ajrothm

Thanks for the great info.

You are a scientist on this stuff....

C7/Z06 Man

Higher octane may be a good thing to "help" stave off knock.

Boostane brand octane booster from what I have read works as well as Torco and my understanding is that Boostane will not leave a buildup of residue on the spark plugs like Torco.

I have tried both; and Torco does leave a residue on the plugs. It's been a while but I don't remember Boostane really leaving a build up on the plugs like Torco.

If I had to pick which octane booster gave the better result I would have to go with Boostane. I used a half can (16 oz.) to approx. 8-10 gals. of 93 and went faster than with the Torco used in a stronger concentration.

Rookieracer

It would certainly be interesting to see lambda results on these cars pre and post cats. My guess is the tail pipe readings are showing leaner than what we would see pre cat.

Higgs Boson

tailpipe definitely shows leaner.