Hey guys, has anyone out there run their "untuned" C7Z (A8) with a Halltech and DR's when DA was at or near zero? I ran my best time of 10.77 at 130 with the Halltech but DA was around 2300 (82 degrees outside). My last few track events were in perfect DA (around zero) and my mph was significantly lower. Mostly 122-123. The only things that changed were the weather and "possibly" bad (93 octane) gas, although I seriously doubt it was the fuel. I'm just wondering if the car is getting too much air for the stock computer. I recorded one of my last runs and noticed that it was pulling all sorts of timing. Between 13-14 for most of the run and ended at 10 degrees at 120 mph. Just trying to figure out if there is something to this?

 

Ill be running mine tomorrow at atco so I will let you know.

 

Perfect. Please include the DA and temps. Mine only seems to struggle in really cool air. If our racing season wasn't over here in WI, I'd actually swap back to my stock intake on really cold days to see if there is anything to this? It's about the only thing that makes any sense. Darn stock computer trying to protect itself.

 

Maybe the drop in trap speed indicates your SC intercooler needs to be bled, see Tadge Press Car Prep sticky at the top of the forum.

 

People have been speculating about this for a while now. The thought is that since you do not have a tune the ECU learns your new intake and adjusts to it therefore you no longer make as much power as when you initially installed it. Or it could be you now have a lot of knock and the car is pulling timing. This is why I am highly skeptical when people claim these large gains without a tune. You are not the only one seeing this.

 

I bled my intercooler yesterday to be sure. This is a possibility, but I don't think it was this as the car did get faster at the end of both track events (as the weather got warmer).

 

This is why I would like to see if anyone has run this set up in cold weather after the intake has been installed for quite a while. There is NO question that my car picked up quite a bit of power (mph at the track) after the initial install. I'm just trying to determine if the car is, in fact, "learning" the new set up and leaning out by itself, or if the cold weather was the culprit? Cold weather seems to make sense as the car would be getting much more air than when it is 80 degrees outside.

I wish my drag racing season wasn't over, because I would def switch back to my stock intake on these really cold mornings. It would be very interesting to see how the car would react.

 

I am pretty sure he drove to the track on his record breaking pass with our intake onboard. 93 Octane to the track and 98 fill up there. The ECU cannot adjust that quickly to the higher octane, but will pull timing if it see KR, but the stock intake does the same thing. We have seen as much as 9 degrees with the stock intake onboard, and this was after 600 miles with it onboard.

It is entirely possible to see dynos less that 50 at the wheels, we have seen a half dozen around 30 in 91 Octane states, and even in 93 Octane areas.

I think there is a real benefit to higher Octane than 93. The ECU will end up in the highest Octane table and stay there.

The other factor is our high flow filter. It does allow a lot of airflow, and boost to the otherwise stock LT4. We have likewise seen swings from .5 PSI to over 1.5 PSI gain (11 PSI) in various stock applications. I am not sure at this point why this occurs.

I do know that our Nomex package, along with the wrap for the large radiator hoses near the airbox works like a charm. We saw near parity between IATs and OATs on our Z06, and only +7 degrees after idling 60 seconds post a 130 mph run. Then after 1 block, back to +2 to +4 degrees delta.

In drag racing, sitting in line, waiting for your turn, the engine, water temps, and heat soak could easily promote more KR than on the road, where cooler ambient air provides the deltas we mentioned. My guess is that if one could get the engine down to 180 water temps and much cooler IATs before the pass, you would see record breaking passes.

Smokey's dyno has done extensive research on our intake and found that their 50.6 RWHP dyno was not an anomaly. They can duplicate it over and over again, doing the install same day, same dyno, same car and conditions. They did see +30 RWHP on Peter's Z06 (the owner) but he had driven the car for 700 miles or so, and the dyno was done under different (hotter) conditions. They did tune the car, and ended up with the same RWHP as the first Z06, which is not going to be subject to different weather conditions the way the stock PCM dictates.

Do I recommend tuning? Yes and no. Yes if you want the highest performance available with our intake and want it not to be subject to so many nanny events. No if you want to keep your warranty.

When we first put our RZ on the market, one tuner saw 30 RWHP untuned, and 45 tuned. The numbers tell the story.

Our Z06 put down 32 RWHP with our intake onboard for 2,500 miles, but those numbers were done with the reverse. Halltech dynoed first, stock dynoed second. our numbers were 608 RWHP without tuning, which is pretty sweet, but the delta was not a record breaker.

All of the dynos done prior to September were done without the Nomex heat shielding so some of the lower numbers might improve with our Nomex setup.

And, in summary, look at what we are talking about 50+RWHP or 30 RWHP. We have 17 different shops that have reported over 45 RWHP, 12 over 50, and 6 around +30 (most in 91 Octane states and A8s)
Show me any other single mod in the world that brings +30 RWHP to the Z06 and provides 685 to 705 HP in the real world. We were hoping for +20 when we developed this intake, and we were stunned when the first 5 dynos were over +50, including one that was +60 HP in Germany. I found out later that they have 95 Octane there, so that helped.

Jim

 

We are in the process of purchasing a much larger facility here in Wisconsin, which should happen sometime in November. We will likely be able to do installs there next year. Tuning? Maybe. Exhaust? Yes, with GM approved systems.

We have several huge things happening next year, that will transform our business model.

Jim

 

I hope that everyone understands that this thread was in no way created to try and bash Halltech. I am very happy with his product and excellent customer service, I am only trying to better understand what our "stock" computers like and why my numbers fell off at the track in perfect conditions. Nothing more. I get all of the dyno claims, I want to see drag strip results so we can all learn what our cars like. I'm not willing to throw my warranty away for a tenth or two at the track.

 

Jim, you mentioned... "In drag racing, sitting in line, waiting for your turn, the engine, water temps, and heat soak could easily promote more KR than on the road, where cooler ambient air provides the deltas we mentioned. My guess is that if one could get the engine down to 180 water temps and much cooler IATs before the pass, you would see record breaking passes."

This is the main reason for this post in the first place. I did NOT see better results with cooler temps and cooler IAT's. I always prepare the car the exact same way at the track. This was not a variable. I have been drag racing for over 20 years and I am fully aware that sitting in line and other things can effect the outcome. My water temps were around 180 each run and I already have the Nomex sleeve and the wrap on my coolant hoses beneath the intake. It has to either be the cool air (too much air) or the fuel (octane)?

 

It's not the gas because you have not changed that right?

 

My normal routine is to get 93 octane (no ethanol) fuel at the station 20 miles from the track. I put in half of a 32 oz can of Torco (fuel additive) at the station so it has plenty of time to mix before racing. I usually race with around 1/4 tank of fuel. The only thing that changed from my routine was the temperature.

 

It could be the fuel. I noticed you are in Wisconsin. I am sure it has started to get below freezing there at night at least. So I am pretty sure the fuel companies have moved to their winter formulas which could be a factor, so I wouldnt completly rule it out yet.

What did you data log with? And what parameters did you log? You may have enough info to tell why the ECU pulled timing.

 

I may have found the culprit. I just noticed that I may have a large air bubble in my intercooler tank? As we all know, that's a great way to have the car pull lots of timing. I'm going to have it drained and properly vacuum filled ASAP. I might also try and throw it on a dyno and data log everything before I put her in storage. I'm really hoping this is the issue. Makes sense though. Frustrated that I didn't know to check the tank earlier.

 

Or get yourself a box that extends the amount of inter cooler fluid that has its fluid level above that of the inter cooler.....bubbles will go to the highest point over time.....self fixing....

 

The air bubble in the tank is due to the "top" inlet coolant fitting in the tank being lower than the top of the tank where the bolt on plate is located. The exit fitting to the pump of course is way below the coolant surface so that the air pocket trapped at the top of the tank will pretty much just stay there and not reduce cooling.

You could "try" taking the lid off the tank and completely filling the tank so that when you reinstall the lid maybe you can get all of the air out.

The coolant tanks that have a screw on cap, the cap location is/usually the highest point of the tank so you just fill the tank up to the top of where the cap screws on.

I don't think having a bubble in the top of the coolant tank will hurt. It's pretty much like having an air pocket at the top of a radiator overflow bottle/tank, as long as the fluid in the bottle does not get low enough to let air back into the cooling system no problem.

 

I appreciate the reply. I have tried filling the Granatelli tank several times. The reason I'm concerned is that I watched my mph at the track fall off significantly the last few weeks. I've read other posts saying that the "air bubble" at the top of the factory tank is normal, however, it should be no larger than 1-2". Mine is much bigger than that. GM also says that if enough air is trapped in the system, the car will have drastically reduced power and pull all sorts of timing. That's exactly what I've been experiencing at the drag strip

 

If that's so than why did your car pick up on "higher" DA days?

I think you really know the answer but just don't want to face it.

Most likely if you have to much air in the stock system the way GM set it up it may circulate in the system having an effect on the pump/pumping action. I really am just taking a shot in the dark but maybe if a large enough pocket of air gets to the pump it may stop pumping. I know you have heard of priming the pump, well maybe the pump can lose its prime.

PS: That is why they put a viewing window in the tank which is a great selling point. You can check if the pump is flowing by just taking a look and if you really can't tell for sure than take the top off and check for flow. The stock set-up does not really have that so I would just grab the two hoses; one should be cooler and the other (return) hose should be hotter.

 

Sounds good. Please be advised about the dyno.

Folks get varied results on the dyno. The reason is even with the huge gigantic fans blowing on the front of the car it will not dissipate or remove heat fast enough for the blown and already heat challenged Z06.

So what you find is your first run (if the car is fairly cool) will be very strong. Then your subsequent runs will drop by as much as 50hp and 50 ftlbs of tq. This is where you will see as much as 7-10* of timing pulled. This is due to a form of heat soak created because the entire car is sitting still and not moving through the atmosphere. Takes 1 run to see this on the dyno during the summer. Happens at the strip as well but not as bad assuming you have to wait your turn in line before each run. Can and has happened on the street but much harder to create this condition before you go to jail.

That being said if your intercooler coolant isn't working as it should it could also create a form of heat soak (increased charge temps from compressing boosted air) with the result being the PCM pulling timing.

Again if you logged or log the correct parameters you can see all of this in the data.

Good luck