Scott Erickson captures the new C7 Corvette Stingray at Laguna Seca ALMS race on 5/11/2013:
Sometime ago, I wrote a brief article on drivability and starting problems due to low battery voltage. This is a follow up based on some recent conditions that I experience with my electrical system. I was sitting at a traffic signal one afternoon and I noticed my dashboard voltmeter was reading fewer than 12 …View full post
From the archive: by James Prunty © 2009 As with most Corvette enthusiasts, I was deeply involved in an engine conversation with Charlie Lipscomb while looking over his ’62 rebirth. Charlie suggested that I might want to consider drafting an article for the clubs newsletter. So, off to the library and deep into the cyberspace I ventured to learn …View full post
by James Prunty The Cabin Air Filter doesn’t get a lot of mention and generally slips the performance enthusiasts maintenance until the dealer mentions it. At $60.00+ from your friendly bow tie service writer, it’s one of those things that you say, “I’ll do that myself, later.” The operative work there is “later” …View full post
Sometime ago, I wrote a brief article on drivability and starting problems due to low battery voltage. This is a follow up based on some recent conditions that I experience with my electrical system.
I was sitting at a traffic signal one afternoon and I noticed my dashboard voltmeter was reading fewer than 12 volts. I was a bit surprised and my mind wondered to alternator or battery replacement! As I drove away from the signal the voltmeter rose to 13+ volts leading me to think that possibly my 15% under pulley may have been the reason. With an idle of 725RPM, applying the math still kept the idle above OEM on a stock engine, the charging dilemma started to grow.
Since my battery (Optima Red Top) was only three years old, I was questioning whether it was dying an early death. I contacted Optima and relayed the circumstances surrounding my recent events. Tech Support suggested that the battery was becoming sulfated. Sulfur in the solution leaches from the electrolyte, sticking to the lead plates as converted lead sulfuric crystals. This process interferes with the ability of the battery to accept, hold and deliver a charge, and left unchecked will render the battery useless far short of its designed life. This can be reversed as many chargers have a “de-sulfating” mode which pulses a charge into the battery.
I have a CTEK 7002 that is covered with icons, but nothing close to “de-sulfating.” That prompted my second call to their tech support. Going thru the problem with them, they told me that there was an icon on the charger that looked like an Optima Battery:
CTEK told me to cycle the battery thru that selection, which would perform a series of pulse charges which would break up the sulfur buildup on the battery plates and allow the battery to charge more efficiently. Also, the tech told me that to run the Recon option:
The tech also told me that I should run the recon option the Red Top at least once a year and that would extend the life of the battery. So, after a weekend of charging following CTEK’s recommendations, the voltage readings are back to normal!
Sulfation also occurs when a battery sits for long periods of time without charging and the electrolyte solution begins to break down. So, for those of your Corvettes which are not daily drivers, you may want to consider a smart charger.
In closing, a related event that surprised me was “Check Charging System” error message. Again, the alternator/battery scenario ran thru my mind. However, surprisingly enough, this message is very common when you change to a colder range spark plug. As part of my cam swap, I installed an under pulley and NGK TR6 spark plugs. Go figure!
by James Prunty
From the archive:
by James Prunty © 2009
As with most Corvette enthusiasts, I was deeply involved in an engine conversation with Charlie Lipscomb while looking over his ’62 rebirth. Charlie suggested that I might want to consider drafting an article for the clubs newsletter. So, off to the library and deep into the cyberspace I ventured to learn about tuning. Five books and one home tuning course latter, I found myself being amazed by the sophistication EFI engine management.
First, Two things. My research focused on the LS2 (since that’s what I have) and to echo Scott Brown’s words:
DON’T TRY THIS AT HOME, EVER!
The GENIII/IV engine family represents a large step forward in performance and technology for Chevy. Although still pushrod activated, it rivals the specific output and emissions of the most advanced OHC competitors with the latent potential for remarkable performance gains. The goal here is for the educated enthusiast to be able to come away with
something as we explore the nuts and bolts of LS engine basics and reinforce what is really going on under the hood. As with most performance enthusiasts, we don’t want to compromise. We want tons of power, reliability, drivability and most importantly, worry free operation.
Data Logging – This was my first step, to find out what was happening when I was either cruising or exploring wide open throttle (WOT) conditions at Irwindale. In order to do this you must have an OBDII capable data reader that allows you to record periods of time to measure transients and WOT behavior. Without going into a commercial for the dozens of you’ll find for sale, I’ll simple tell you what I got. I found an inexpensive ELF327 OBDII interface on eBay for about $10.00 and acquired a copy of Palmer ngineering’s PCMscan. This software and hardware combination allowed me to see what the MAS (Mass Airflow Sensor), MAP (Manifold Absolute Pressure) Etc. were doing.
This particular program has the ability to scan 40+ PIDs (Parameter IDs) RPM, vehicle speed, timing and so on. However, the more data you get isn’t necessarily important. There’s a lot going on and if you’re scanning more than 25 PIDs the possibility that you can lose some data is more than a possibility. What you need to focus on are the PID’s that are important to your goals. Again, this is an inexpensive and easy way to monitor your sensor activities. However, it lacks the functionality to see what’s in the calibration tables, and what those tables are telling your computer.
This pushed me to confirm what I did and didn’t know about the sensors on my C6, what they did and what that meant. I investigated more sophisticated tuning software. There is a lot of it available, but I selected HPTuners. The first thing this application brought to my attention was not only the importance of the Air/Fuel ratio, but its relationship to intake air temperatures and cylinder air mass. I had an immediate flashback to my ’61 Corvette with a 283, dual quads, cam, solid lifters and a four speed. I remember setting both sets of points, setting the timing with the fully mechanical advance (no vacuum) and playing, for what seemed forever, with jet combinations When that car was tuned, it was tuned for WOT all the time, regardless of cruising or drag racing (and got 6 MPG whether cruising or drag racing).
What I found remarkable about the LS2 was how it could be tuned for WOT and, not or, cruising. By determining the cylinder air mass during a WOT condition from a data scan, you can isolate the operating area to make your timing adjustments. The graft below shows a cylinder air mass axis and an RPM axis. The numbers in the cells are current spark advance numbers that you can adjust without impacting other operating ranges.
The following graphic represents timings setting that the computer pulls for various “real time” driving condition.
These spark settings can be influenced by two other spark tables, the IAT (intake air temperature)
Under the same cylinder air recording used above and applied to this IAT table, you can
see the timing being backed out because of increased air temps. ..and knock retard
As you can see, the possibility of losing a lot of timing you weren’t aware of is now right in front of you. Here is a real time example of WOT on the 1/8th mile at Irwindale.
The intersection of the timing and knock retard in the white oval is at just below .9 seconds of WOT. Note the timing, white on the graph is rising, until the knock retard (about 6 degrees) kicks in. Combine with the timing reduction from IAT table (see above), spark
advance averaged between 13.5 and 17 degrees advance.
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As you can clearly see, tuning for performance requires knowledge between the sensor relationships.
by James Prunty
The Cabin Air Filter doesn’t get a lot of mention and generally slips the performance enthusiasts maintenance until the dealer mentions it. At $60.00+ from your friendly bow tie service writer, it’s one of those things that you say, “I’ll do that myself, later.” The operative work there is “later” because the relevance factor just isn’t there for you.
The Cabin Air Filter is referred to in the C6 Corvette Owner Manual as the “Passenger Compartment Air Filter Element” and is considered a “Normal Maintenance Replacement Part,” similar to an oil change. Removing and inspecting this filter element at 6,000 miles will explain why it is a maintenance item! If you’re noticing a reduction in air flow when using your air conditioner, it may be time to inspect this filter.
Replacing your Corvette’s air cabin filter is a relatively simple repair that can be done in a few minutes without tools. OEM air cabin filters are similar to air filters but cabin filters have far superior filtering capability because it is filtering the air you’re breathing while driving your car. To determine if your cabin filter needs to be changed, locate the filter housing door behind the battery in the engine compartment:
remove the filter housing retainer clips (wire horseshoe shaped ) and remove the filter. If the filter is visibly covered with debris, change it! If not, gently tap the filter, if you see dust falling from the air cleaner it is filled to capacity and needs to be replaced. (It is not recommended that you clean the filter with compressed air or a leaf blower.)
You can buy a replacement filter from the dealer or any auto parts store. There are 2 types, one is a basic paper filter you can get for about $15, or, the other, like the OEM product, is a carbon filter that costs more but meets OEM specs. You’ll be amazed at how dirty the filter becomes in a couple of months and in my opinion, it’s worth spending the extra money to get a carbon impregnated filter. If you eat in your car, i.e. French fries for example, the carbon filter is important if you don’t want the smell lingering for a couple of days.!Here is a list of the most popular C6 charcoal impregnated filter replacements:
· Purolator C25623
· WIX 24480
· BOSCH C3722
· ACDelco CF139 (15861929 / CF131C cabin filter.)
Prices range from $18.00 to $35.00. Note the “C” in the part number indicates it has activated charcoal.
Driving without a passenger compartment air filter is a mistake and can cause water and small particles, like paper, leaves and sand, to be pulled into your climate control system which may cause damage and most likely, expensive repairs.
Last Friday we had a chance to go to the Petersen Museum and see the “unwrapping” of the C7 on the West Coast. Well not all was as planned, we were supposed to be able to see the car at 6 then no that was an error it was going to be shown at 9, they didn’t unwrap the car until about 10:30 and about 11 o’clock I could get close enough to see the car and take a picture.
The car was shown in Cyber Gray. The car was actually a fiberglass shell that was shown to GM brass as the final and approved design. So the car we saw had no drive train, no engine, no interior it was just a shell with working LED lights. Unfortunately the car was behind ropes and with no interior there was not much to see or shout about …
Ok that is not true the car is just so cool. The lines are great and blend very well, they are not too sharp or edgy. This car when available with a wide body kit like the Z06 or GS will be just beyond cool, but as it sits right now, it is the next generation!
It was interesting to hear Kirk Bennion the exterior designer refer to it as having a European influence. This was clearly to comment on the folks saying it looks like a Ferrari. I think it has a lot of similar traits as Lighting McQueen from the Cars Movie – check it out. Did Disney know something or did the designers like what Disney had done for the movie? He also spoke to the tail lights saying that the designers want someone that was a mile behind the C7 and losing ground; to know they were chasing something special and not just another Corvette. He also spoke to the new interior – although we did not see it. Which of course has been a concern or a long time. He even made several references to Porsche in his presentation. I was sitting next to a “German” car collector as his wife put it; and when the issue of the interior came up he just smiled. By the way he has owned seven Corvettes, so he said he is hopeful they got it right. Kirk also spoke of the functional vents in the hood for down force, side and rear for brakes etc. All of the vents were visible as you looked at the car, but they weren’t too much or too plastic looking. I thought as I was looking at the car the vents seemed to fit in – like they should be there. This was a clear effort to counter the comment “I sure wish there was NOT a sale on vents when they built the car”.
One other point Kirk was telling a story about driving the car around the test track at GM for a video shoot and said he was told to put his foot in it and make the car roar by the camera. He said he had the hammer down at 140 mph in 4th and almost 7,000 RPM! He said the camera guys missed the shot so he had to do it again – too bad! But what I thought was interesting was he said almost 7,000 RPM – is that the new redline? A rumor on the ZR-1 forum was the engine can take a redline of almost 10K and in the next generation of the engine it may be at that level.
I have to say I thought the C6 was great when it came out, but it was especially good when we went and saw the Z06 introduced at the LA auto show we actually got to see a running car. So although I was somewhat disappointed because I so wanted to see the interior of the car, that I did see however was just great. I am really looking forward to seeing one soon that is more than just a shell.
The photos of the car on the web are better than any of mine, I just could not get close enough. The photo I attached shows how a carpet “deck” was inserted into the interior so nothing below the door line was there. Note there is even a “half” a steering wheel.
I think this will be a hit or I should say I hope it will be a hit.
The opinion express are mine and do not reflect the opinion of anyone who knows anything about what is important or what is not. They are the ramblings of a Corvette fan.
All the best
C7 Corvette Stringray is a special generation of Corvettes.
Corvette C7 was relieved at the Detroit Auto show 1/13/2013. Base price will be $53,000. That price includes a freshly redesigned direct injection 450 HP V8 engine, carbon fiber body panels and an all aluminum frame. Plus 0 to 60 in 3.9 seconds.
The C7 is a completely new car with only a hand full of C6 carrier over parts. With its new sharper lines, entirely reworked interior and high tech dash it is said to be designed to attract a younger buyer.
The official GM C7 Corvette Stringray website.
Mark Reuss, President, GM North America and the new C7 Corvette on stage at the Detroit Auto Show. The GM official C7 Corvette Stringray reveal Video the Reveal starts at the 33.00 minute mark.
In this photos you can see the small rear window and the intake vents on top of the rear fenders. The vents cool the breaks in the base model and with the Z51 option the inlets direct air over a trans and differential cooler.
Merry Christmas and congratulations to our friend, Rosemary Rodriquez. Rosemary was voted “Member of the Year” for 2012. Danny and Rosemary have been members of PVCA for about 8 years. In that time Rosemary has received member of the year three times. Every year these two people will be seen at most functions and usually lending their hands to assist anywhere they are needed. Thanks again Rosemary for all the love and support you show our club.
I’m sure most of remember the 2003 accident in which an elderly driver plowed through an open-air market in Santa Monica, killing a dozen people and injuring about 60 more. Since that accident, The National Transportation Safety Board has been pushing for Event Data Recorders (Black Boxes) in all passenger cars and light trucks. GM has been installing them on their most popular models since 2000, and just about every model in the last model year.
So, if you own a C5 or C6, every time they get behind the wheel, there’s a snitch along for the ride. Chevy has been quietly tucking EDR’s (Event Data Recorders), which automatically record the actions of drivers and the responses of their vehicles in a continuous information loop, into most new cars for years. Basically your car is a computer now, so it can record all kinds of information. When a car’s airbags deploy, or the car computer believes it has been involved in a crash, inputs from the vehicle’s sensors during the previous 10 to 30 seconds, the EDR automatically preserves:
1. Vehicle Speed
2. Throttle position
3. Brake use (was the brake applied?)
4. Change in forward crash speed
5. Maximum change in forward crash speed
6. Time from beginning of crash at which the maximum change in forward crash speed occurs
7. Ignition cycle, crash (number of times the engine had been started prior to the crash)
8. Ignition cycle, download (number of times the engine had been started prior to downloading the EDR data)
9. Seat belt status, driver
10. Frontal airbag warning lamp, on/off
11. Driver frontal airbag deployment, time to deploy for a single stage airbag, or time to first stage deployment for a multistage airbag
12. Right front passenger frontal airbag deployment, time to deploy
13. How many crash events?
14. Time between two crash events, if applicable
15. Did the EDR complete the recording?
The design is to gather information that can help investigators determine the cause of accidents and lead to safer vehicles. But privacy advocates say government regulators and automakers are installing an intrusive technology without first putting in place policies to prevent misuse of the information collected. Not surprisingly, data collected by the recorders is increasingly showing up in lawsuits and high-profile accidents. A federal requirement that automakers disclose their existence in owner’s manuals didn’t go into effect until a couple of months ago.
Despite privacy complaints, the traffic safety administration so far hasn’t put any limits on how the information can be used. About a dozen states have some law regarding data recorders, but the rest do not. In 2004, California became the first state to enact legislation (Calif. Vehicle Code § 9951) requiring manufacturers to disclose to customers whether event data recorders are installed in vehicles. Look in your manuals!
EDRs and the data they store belong to us, the vehicle owners. Police, insurers, researchers, automakers and others may gain access to the data with owner consent. Without consent, access may be obtained through a court order. For crashes that don’t involve litigation, especially when police or insurers are interested in assessing fault, insurers may be able to access the EDRs in their policyholders’ vehicles based on provisions in the insurance contract requiring policyholders to cooperate with the insurer. However, some states prohibit insurance contracts from requiring policyholders to consent to access. I contacted my assembly person to find out, and they are researching my question. I contacted my insurance company, USAA, and they assured me that there is no provision in my contract that obligates me to provide that information.
Here is page 464 from my C6 Owner’s Manual:
Here is a list of cars and trucks with EDR’s: http://www.crashforensics.com/files/CDRVehicleList.pdf