It seems that several are curious about what kind of HP and Torque a base C6 with automatic trans can make with tune and headers, CAI and Corsa mufflers. All add on with out busting open the engine. I do not know of another add-on that I think would make a difference. Most of the work is done on the Z06 so this is what I have found on my changes to the C6 with automatic trans working at LG Motorsports. You could add about 2% to 3% to the numbers for manual trans.

Remember first that even if two or three C6 with A6 trans came off the assembly line back to back the HP and Torque could be different by 2 to 4 HP or Torque but all would be in a general range. Hard to explain but some just run different. I do not know whether it is from the way the owner drives in the first 100 to 500 miles or it is just the way it is. Then remember that dynos will be different so this is a Dynojet and that really does not matter as long as you stay with one person and his dyno so you can see changes apples to apples.

That said my 2008 convertible with automatic did not have the base HP or Torque done prior to adding the Killer Bee CAI or Corsa exhaust. But I can tell you what it made after the change and calculate base. Campare the calculate to what LG saw in 2007 on a stock 2008 when it first came out. We added these items: CAI at about 5000 miles and the muffler at about 6000 miles then this change of adding headers at 21500 miles on car. The following numbers are from base plus the CAI and Corsa mufflers.

Stock by LG back when 2008 LS3 first came out in 2007:
HP 370.8 and 363.8 Torque (assume this as starting point but remember it is a manual and the rest of the data is from an automatic trans)

CAI and Mufflers added
HP 383.18 and 375.02 Torque on LG’s Dynojet. At the crank estimate of 18%
HP 467.29 and 457.32 Torque.

Added headers 3” collectors and 2 ½ system which matches factory size. Did not go bigger since I do not plan on a head or cam change. And it was tuned by LG. And I can’t say enough about that experience at LG. Good group of guys that spent the time to explain every thing they did and why. And believe me I asked questions. It did not take them but about 2 hours to pull the base line on the dyno, install headers, and pull the after header change data. I arrived at about 9:45 and shot the bull for about 20 or 30 minutes, looked at the new car they are building to compete in the next two weeks, and then they started about 10:15 and I was driving out about 12:15 back to work.

HP 401.57 and 405.06 Torque on LG’s Dynojet. At the crank estimate of 18%
489.75 HP and 493.98 Torque.

Remember that Dynos can give different numbers from manufacture to manufacture but this is just what I have seen. Assuming a loss of 18% for Automatic verses 15% for manual trans this calculates to the 489.72 HP at Crank and 493.98 Torque at the Crank you see above.

You can use 18% or 15% to calculate. Some people have said it will cost as high as 22% of an automatic but I want to use the lower number. Those people wanting to race dyno numbers can use the 22% since it will give a higher bragging number of what they got at the crank when checking HP or Torque. I do not really care about crank and who has a bigger one only what is on the ground. And really then I am just looking at changes to gross. It is what it is. I do know each will be different between manual and auto because of the HP or Torque when one to one ratio on gear you have to look at what the trans takes to pull pumps, etc in the trans that is not there in the manual. There could be some difference thou small for weight of wheels. Some heavier wheels take long to ramp up and also slower to stop but you could gain something after you got the weight spinning. Makes sense but not sure unless compared on dyno to see if there was an effect on dyno.

Consider what is advertised by GM for the 2008 LS3 430 HP and 424 Torque. But these numbers are done pulling all the hang-on equipment that will be pulled like alternator, pumps, air conditioner compressor (clutch not engaged), etc. So actual crank could be another 20 to 25 HP more, which would make more sense when calculating a possible crank HP or Torque change for just CIA and Mufflers. When you look at calculated HP and Torque at the crank, the crank change for CIA and Muffler starts at about 450 Hp and moves to 478 HP with the two changes and Torque crank starts at 444 and moves to 457 Torque and this is realistic change at the crank of 28 HP and 13 Torque. Like wise I mentioned all this so that when you see a ground HP of 383.18 and Torque of 375.02 most likely stock will be 369 HP and 364 Torque or a gain of 14 HP and 11 Torque at the wheels on most for the two changes. These calculated numbers also meet what LG found when in July 2007 when they ran the new stock LS3 on a 2008 car and got at the wheels 370.8 HP and 363.8 Torque stock.

My graph is below from dyno.


What you should notice is the Torque first. Torque launches and HP pulls the big end as we say in drag racing. The Torque increase is coming in fast around 2300 RPM and nearly full in at 3000 RPM and holds to about 5000. HP starts coming in strong at about 4500 and pulls the big end as Torque drops. There fore the saying Torque launches and HP pulls the big end. What it shows is that regardless of red line you need to hit the shift button at about 5000 to 5300 and assume it actually shifts between 5300 and 5700. After that if you had a G meter on the car you would most likely see the meter still show G’s but time to G’s would be dropping. I can not see any thing that says when you reach 6000 RPMS that you experience any significant time gain from this reading. That is my feelings on this graph and car.

Now by the seat of the pants it can be felt. If I drop the traction control off and step on it at 30 mph it will set the tires turning instantly and take a second of two to catch up. We did of course tune TM but did not totally remove it. I just do not trust a total removal and we did tune for 93 octane which means in some parts of Oklahoma or Arkansas you I will have to put an octane boost with the tank to be safe when driving hard. If no hard acceleration I may be OK but why take the chance.

I hope this helps you.

 

Interesting post, I got similar numbers of 400.66 RWHP & 401.85 Torque at LGM lasr Fall on my '08 A6 with LT headers and NPP, but no CAI.

Who's CAI are you using?

 

My understanding is that manufacturer calculations on crank horsepower are not without the accessories, fluids, belts, etc. Therefore, the real number is the real number.

Further, I don't know if you can use an add-on factor (or loss factor) to actually discuss or convert rwhp compared to crank horsepower. But if you feel comfortable with those percentages, so be it.

Interesting post.

 

Killer Bee CAI and happy with install was not hard and I did cut the bottom as suggested.

 

I can not disagree with you I just tried to cover all bases. The bottom line is wheel horse power and torque and that is the numbers that should be noticed. Just wanted to answer some questions I saw on what the add-on changes could do with out opening up the motor. Some like to talk about Crank HP but it is really a calculated number so why go there. like I said it was added to the conversation for snorts and giggles since it is a calculation.

It what's on the ground that counts.

 

Thanks again from all of us here for letting us be part of your Corvette experience.

Always nice seeing you, and as always let me know any time if you have any questions. Stop by and see us any time!

 

Very nice results from your bolt ons

 

2008 C6 Convertible - Automatic

418 RWHP

Stainless Works Headers and Hi-Flow Cats
Callaway Honker CAI
Low Temp Therm
Dyno Tuned

All work completed by MTI Racing in Atlanta

 

Looks good and I bet you are as happy as I am.