long tubes with high flow cats

[Maroon 6.2L SS]

Can anyone give me an idea/opinion on how much hp/tq can be gained with the addition of long tubes w/high flow cats on an A6?

[sixty9fordkiller]

the number will vary from dyno to dyno, engine condition/health, but 35ish rwhp increase is kind of normal

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[sixty9fordkiller]

***assuming you're gonna tune for it as well

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[pyroguy]

25-45 rwhp. With a 2010 L99 car, you should be seeing somewhere in the 360-370 rwhp and 380-400 rwtq. My car made 365hp/390tq with long tube headers, cold air intake, ported throttle body, and catback exhaust.

[frey.199]

I plan on putting on headers myself, but I'm not sure if I want to wait to have it tuned because of future mods (Don't want to pay to have it tuned, then a week later tuned again). My question is, can you install headers and just not tune for some time till your ready or is this bad on your engine? CEL (02 sensors, not a huge deal)? Anything? Just curious.

[PepeLePew]

Originally Posted by frey.199

I plan on putting on headers myself, but I'm not sure if I want to wait to have it tuned because of future mods (Don't want to pay to have it tuned, then a week later tuned again). My question is, can you install headers and just not tune for some time till your ready or is this bad on your engine? CEL (02 sensors, not a huge deal)? Anything? Just curious.

what are your future mods and how soon do you think you'll do them? If it is really just a week, then you should be fine to wait until you are all done. In the meantime, if it were me, I wouldn't be putting a lot of miles on the car and I certainly wouldn't run it hard.

From what I've heard, contrary to what happens when you put headers on an older carburetor car, your car will run much richer. I believe this may be due to moving the O2 sensors further downstream which makes the computer compensate more. Others will correct me if I am wrong though.

If you are more than a week out from your other mods though, I would certainly go ahead and get a tune. Most tuners I know of in my area offer dyno tuning by the hour after they unlock the computer. My tuner charges me $125 an hour for any dyno time required since he did my original tune. Give your tuner a call and see what they recommend and how much he'd charge for initial tune and subsequent tuning mods for other upgrades.

[pyroguy]

Originally Posted by frey.199

I plan on putting on headers myself, but I'm not sure if I want to wait to have it tuned because of future mods (Don't want to pay to have it tuned, then a week later tuned again). My question is, can you install headers and just not tune for some time till your ready or is this bad on your engine? CEL (02 sensors, not a huge deal)? Anything? Just curious.

You can drive around without a tune for a little while, just don't beat on it and you'll be fine. What future items are you planning on modding on your car?

[weSS1LEy]

I drove without a tune for a while with headers. I did open it up a couple times. In retrospect I probably shouldn’t have risked running lean anywhere in the rpm range. You should tune as soon as possible unless you’re good about not beating on it

[frey.199]

I would like to boost eventually, but I'm not 100% sure yet what all I'll still want to do after headers. Very possible a cam, but I'm still iffy about that with the pros and cons of what they have to offer. I guess I was exaggerating "a week" hahah, it will def be longer than a week. I have 2010 ss. Is a vehicle running rich bad for the engine? Or does that just mean bad fuel economy or?

[PepeLePew]

Originally Posted by frey.199

I would like to boost eventually, but I'm not 100% sure yet what all I'll still want to do after headers. Very possible a cam, but I'm still iffy about that with the pros and cons of what they have to offer. I guess I was exaggerating "a week" hahah, it will def be longer than a week. I have 2010 ss. Is a vehicle running rich bad for the engine? Or does that just mean bad fuel economy or?

If the car is too rich for too long, you'll foul up the plugs pretty quick at first. In the long run, you could get excessive carbon buildup that may lead to valves sticking and poor combustion. Carbon can also create hot spots in the combustion chamber that will become more apparent after you correct the AFR with a tune. These hot spots often times lead to pre-ignition and detonation which is very harmful. I don't know how long you'd be able to run safely with a pig rich condition, but it's certainly not worth it.

Also, you'll find worlds of conflicting information on the internet about whether or not your car will run richer or leaner with headers and no tune. Either condition can be dangerous. I think the only way for you to know for sure what your car is doing, is by getting it tuned. The tuner should be able to tell you AFRs before he makes modifications.

Oh and my vote is to get a cam and boost... why just do one when you can to do both. Seriously though, a cam is a good place to start. Depending on how crazy you go, you can pick up a good 50whp give or take. And if you know you want to go boost in the future, get a boost cam to start with and save the trouble of swapping it out a second time.

[sixty9fordkiller]

Originally Posted by frey.199

I plan on putting on headers myself, but I'm not sure if I want to wait to have it tuned because of future mods (Don't want to pay to have it tuned, then a week later tuned again). My question is, can you install headers and just not tune for some time till your ready or is this bad on your engine? CEL (02 sensors, not a huge deal)? Anything? Just curious.

Car will run lean at higher rpms
You can drive it easy but it will definitely ping up top

a tune is cheaper than a burnt valve or piston

[frey.199]

Originally Posted by PepeLePew

If the car is too rich for too long, you'll foul up the plugs pretty quick at first. In the long run, you could get excessive carbon buildup that may lead to valves sticking and poor combustion. Carbon can also create hot spots in the combustion chamber that will become more apparent after you correct the AFR with a tune. These hot spots often times lead to pre-ignition and detonation which is very harmful. I don't know how long you'd be able to run safely with a pig rich condition, but it's certainly not worth it.

Also, you'll find worlds of conflicting information on the internet about whether or not your car will run richer or leaner with headers and no tune. Either condition can be dangerous. I think the only way for you to know for sure what your car is doing, is by getting it tuned. The tuner should be able to tell you AFRs before he makes modifications.

Oh and my vote is to get a cam and boost... why just do one when you can to do both. Seriously though, a cam is a good place to start. Depending on how crazy you go, you can pick up a good 50whp give or take. And if you know you want to go boost in the future, get a boost cam to start with and save the trouble of swapping it out a second time.

How do I know what boost cam to get or where? Suggestions?

[PepeLePew]

Originally Posted by frey.199

How do I know what boost cam to get or where? Suggestions?

I am a big fan of Texas Speed personally. They offer a variety of stages for their boost cams which are variations of their NA cams. The main differences are they a wider LSA and less intake and exhaust duration than their NA counterparts. They make slightly less power in NA form than the NA cams because they don't breathe as well as the NA cams. Conversely, they allow less boost loss because there is less overlap in the intake and exhaust valves being open.

There are certainly a bunch of other quality CAM companies out there like GPI that get great reviews from the guys on this forum. I am not sure if they have boost specific applications but others can chime in on that as well.