Mainn

Hey everyone,

Two days ago I picked up a really, really rough 2008 Corvette with the A6 transmission for cheap to use as a daily driver. I have already decided it needs a tune, mainly to adjust the transmission's shifting. There's also a dead spot at about 10-20% throttle (is this normal?), which hopefully a tune would be able to fix too.

Now, I will admit, I am a Mustang guy. In the Mustang world, I know that the device most people use to tune with is either an SCT X3/X4. Most of the time you go through a vendor; they ship the SCT tuner with a tune loaded on it, that was built for your specific modifications. Once you receive the tuner you load the tune into the car, and datalog for the tuner so that they can adjust the tune for your car. This is repeated until the tune is perfect.

There is also the SCT Pro Racer Package, which you can use to tune the PCM yourself. From my research, this is similar to HPTuners or EFILive for the Corvette's. I tuned my own car using the PRP so I know how to tune, and if I have to, I am willing to learn HPTuners. However, for the Corvette I would rather use the method in the previous paragraph because, to be honest, I don't want to spend the money on a wideband, spend the time to learn GM PCM's, or spend the time to tune it.

The main thing I don't want is a 'canned' tune, which isn't built for my car or the modifications on it. If there are mail-order tunes for Corvette's that are built for my mods and my car specifically, I'd be interested. My second option is tuning it myself with HPTuners, but that is something I would not prefer to do.

Another thing is that I have no idea what mods the car has. I can send photos/videos of the engine bay/exhaust for the tuner if necessary, to see if anything stands out. I did notice a Vararam badge on the intake, so I'm assuming it actually does have a Vararam CAI, but that's as much as I know. This is another reason why I don't want a generic, canned tune.

Unfortunately, a dyno tune isn't possible as the car is in the Middle East. There are no tuners whatsoever around here, so it has to either be a mail-order tune, or I have to tune it myself.

If anyone could help me out and recommend any tuners, or give me any other options that can be done, that would be great. I really am clueless when it comes to these cars!

Thanks a lot!

Zero1

Silly idea, but lets assume everything else is stock. Have you hooked up a scanner to see if TPS 1 and 2 agree and watched the percentages on data? Also watch the Accell pedal sensor (APP). Would show if there is a dead spot in any sensor or if possibly the Throttle blade is getting stuck. Check it out, as it is a known thing on every truck I work on in the shop. Crap builds up in there especially on the blade and the sides. Can't hurt.

Do you have any codes currently even no mil?

-Steve

Mainn

Honestly, I have no idea if there are any current codes. Before buying it I did get it hooked up to a scanner at a Chevy dealer, but I had no idea what the guy was doing, what codes were current etc. so it wasn't any help at all really. It does have the 'Service ABS, service active handling system' warnings, an airbag warning, and the pressure for the passenger side tires read 0. No CEL though, after fixing the low oil pressure issue.

Sorry for my ignorance; what is an MIL?

Thanks for the suggestion on the dead spot issue! I'll take a look at it. I am still looking for a tune, to hopefully help out the transmission's shifting, but the dead spot would be really nice to get rid of.

Seadawg

Before I bought anything, I would talk (or PM/email) with Chuck of COW (he is a forum vendor out here).

He does a lot of remote tuning.

It really sounds like there are mechanical/electrical issues that need to be fixed first, before you even begin looking at a tune, however. A real problem could be causing your shifting issues, and a tune won't help for that.

I would not complicate my life, until I got all of the troubleshooting out of the way, and I got it back to proper operating order first.

Then, consider a tune

Mainn

There's a LOT of mechanical/electrical issues on this car. The indicators are permanently lit when with low-beams are on at night, as one example. Very butchered. When we bought it, we were told that the transmission is weak, and it does take about 2 seconds to shift into reverse/drive. When it does shift, it's very firm.

I don't believe that there are any engine codes now that the oil pressure is reading correctly again, but I'm not sure.

I'm not going to lie; for the price we got this car for, it's really going to be used as a beat-up daily driver for a year or so. I'm just looking for a tune to account for the (unknown) mods that are on it, to make it a bit more responsive and to improve the shifting a bit. I've always liked Corvette's; if only I could get one in really good condition.

Thanks for the recommendation on Chuck! I'll send him a PM/email in the near future.

Zero1

What all indicators light up when the lights are on? Possible ground issue. I can shoot you any schematic you need.

-Steve

0Chuck CoW

Hey there. Most scan tools won't pick up trans codes (if any). Call me after 12 noon friday cause I got a DR.s appt tomorrow morn.

Describe to me what's going on and I'll tell you what's likely happening.

914-332-0049
Chuck CoW

Mainn

Whoops, I didn't proof read my post very well. My bad.

When the lights are turned on, the two indicators at the front fender turn on. The ones next to the headlights in the same housing also turn on. There were also red lights on the rear fenders that turned on, I'm not sure if that's normal or not though. There may be others but that was all I noticed. Thanks a lot for the help Steve!


Hey Chuck, I hope your dr's appointment goes well. I'll get in touch with you soon.

tblu92

You pretty much answered your own question--Since a dyno tune or a street driven tune is out you are left with a mailorder tune---
The nature of a mailorder tune is that they never drive the car so it's basically their best guess---However tuners like Chuck Cow have so much experience their best guess is usual very close anyway---
Yes a Varraram has a tendency to be difficult---but not for an experienced tuner
The main thing I would guess is what oct fuel you have there so they can get the timing curve closer-- and what altitude you normally drive in----

Mainn

A mail-order tune was where I was heading, although I'm slowly thinking about just buying HPTuners and doing it myself. I emailed Chuck but have yet to receive a response.

How come a Vararam is difficult to tune compared to other CAI's? Unfortunately I'm only familiar with Ford's but wouldn't all CAI's take roughly the same amount of time and effort to tune (by dialling in the MAF)?

We have 90 RON (86 AKI) and 97 RON (92 AKI) octane here. I understand the car can't run on the 86 octane unless the tuner really drops the timing on the low octane table. It's also at sea level.

tblu92

The learning curve on tuning is huge--Even if you have basic computer knowledge and basic engine tuning experience---A stock tuning file has apprx 450 tables in it and another maybe 400 in the trans file (if an automatic)----
It's not as easy as adding or removing timing or fuel---There are many redundant tables that have multipliers -deductions and adders to compensate for various situations---If you love to tinker and are willing to gamble with making an error that may damage your engine--and spend hours learning the system then it may be for you
You not only must learn all the tuning tables but must also learn how to effectively use the "data logger" so you can get real time data stored and make adjustments according to what the data logger says
As far a the Vararam goes--Most CAI will learn out the fuel trims after about 50 miles of normal driving---The Vararam can change the incoming air flow change so much that you'll get lean codes and must make a MAF table adjustment to compensate--Typically a lean code will pop up when the leaness or richness is beyond 20%----
It really doesn't mean that it's flowing 20% more air( as that would be amazing) but because of the changed air path and relocation of the MAF sensor the readings are changed and or inaccurate--

0Chuck CoW

Hey there.

I'm having some e-mail problems and have missed some, especially the past 2 weeks.

Call me any time after 10am tuesday and I'll be there. Not sure if you PM'd me e-mailed me,

but we get such volumes of communications it's sometimes tough to keep up.

914-332-0049
Chuck CoW

tennblkc6

you have pm

Mainn

Thanks a lot for the help! I understand what's involved with tuning and data logging, after tuning the other car in the household myself (an '08 Shelby GT500 with a VMP TVS supercharger, JLT 123mm CAI, and built 4r70w automatic transmission). After looking through the free trial version of HPTuners it seems the Corvette is quite a bit different tuning wise, but not any more complicated. I'm reasonably confident I would be able to learn most of it with help from a book, similarly to how I learnt with SCT software and Ford PCMs.

I didn't realise that the MAF sensor changed location from stock with the Vararam CAI, that makes sense as to why the MAF table needs adjustment. On the Ford PCMs you have to adjust the MAF transfer function/table whenever incoming airflow changes at all (it doesn't have the ability to learn like on the 'Vettes), so that's pretty cool. Thanks again!

Ah, ok. I'll see what can be done, with time zones and such. Thanks Chuck!

Zero1

LOL, didn't think about that. Guess I'm too used to having the capability. But, yeah you are right on that one.

1Hotrodz

Sorry for my ignorance; what is an MIL? It is an acronym and means:

MIL Malfunction Indicator Light
or
CEL Check Engine Light
or
SES Service Engine Soon

All the same thing

0Chuck CoW

YES.... same things... Different circumstance....

Pretty easy to figure out....

Call and I'll try to help you.

914-332-0049
Chuck CoW

Mainn

Ah, I thought so. I wasn't sure as the only one I've heard is CEL before. That makes sense.


The car is currently at the Chevy dealer to have some things looked at.

This car is actually my father's car by the way, I'm just very heavily involved in it. It's a father-son project in a way.

Once he gets the car back, as we haven't had much seat time in it, he'll go for a quick blast just to make sure everything we suspect is correct. After that, he'll give you a call and let you know what's going on, and what we don't like about it. It should be back either today or tomorrow. Sorry if it seems like we're dragging it along, we both have been very busy recently. Thanks!

Unreal

Buy HP tuners and do it yourself.

Vettes don't learn anymore than Fords, in fact the new fords are ahead of vettes in that category. There is plenty of support for HP tuners and tuners that can help you dial it in, but no one is going to do a better job than you on tuning it. For a basic car like yours, dialing in the maf curve, and adjusting timing tables is as easy or easier than doing a ford.

Spying Beast

Agree 100%