Doug Thorley headers question

[v6sonoma]

Originally Posted by FUN4JT

I've installed DT shorty's and hi-flow cats along with a magnaflow x pipe and Diablo Predator tune, Halltech CAI and so far no codes, this with about 500 miles on the cats. No dyno numbers as yet but I will say that the SOP meter indicates a stronger mid/top end pull, especially after installing the cats. Also the exhaust note definitely changed with the cat's, much raspier with more pronounced popping on decel. While long tubes will ultimately extract more HP I'm pleased with the combo I have.
SC up next...JT

Well with a tune you really shouldn't see any codes. Unless it wasn't done correctly.

[Ivan @ Southwest Speed]

Our before and after.....

The OEM Cats are the bottleneck in the cars.

And yes, a tune will DEFINITELY make a difference...how much is up to your tuner.
Ivan

[wbt]

Originally Posted by Bad Karma

Our before and after.....

The OEM Cats are the bottleneck in the cars.

And yes, a tune will DEFINITELY make a difference...how much is up to your tuner.
Ivan

Shorties with, without or high flow cats?

[2010 4 DW]

Originally Posted by wbt

Shorties with, without or high flow cats?

I would just buy the high flow cats first and then if you feel you need a few extra HP buy the shorties. Best price on stainless mids is the JBA and below is a link to great prices I found on google.

http://www.google.com/products?hl=en...-8&sa=N&tab=wf

[wbt]

Originally Posted by 2010 4 DW

I would just buy the high flow cats first and then if you feel you need a few extra HP buy the shorties. Best price on stainless mids is the JBA and below is a link to great prices I found on google.

http://www.google.com/products?hl=en...-8&sa=N&tab=wf

Thanks. I was wondering if the graph BK posted was with shorties through stock cats, high flow cats or non-catted.

I agree the best bang for your buck are mid-pipe replacements.

[The Yeti]

I've never thrown a code with my Solo cats. Well over 3000 miles and counting.

[topgun1]

Originally Posted by Gunner USMC

Hey guys, I have been thinking of ordering a set of doug thorley shorty headers for my ss. Ive searched all of the forum but cannot find anyone that has a dyno for the V8. I know some of you say its a waste of money to buy shorties but I want to keep my warranty like others. If anyone has these headers that have noticed any power increase on their V8 or have a dyno sheet please post your input. Semper Fi...

check my thread out, you may find it useful. I have dynoed with DT shorty headers on my SS with hiflow cats. definite power gains at least between both of them. Also, DT's shorties and longtubes have neglible difference in HP gains on their website dyno graphs and the shorties have a little more low end torque. I'm happy with my shorties, they are less expensive, still ceramic-coated, they are not throwing codes (headers or cats) and dont' have to worry about clearance issues with the long tubes since my car is lowered. i have tuned so likely voided my warranty but shorties shouldn't if you haven't tuned. I'd go with the DT shorties and replace the stock cats with SOLO hiflow cats. The sound you'll get with the new cats is amazing. good luck!

http://www.camaro5.com/forums/showthread.php?t=91945

[axis]

Originally Posted by topgun1

check my thread out, you may find it useful. I have dynoed with DT shorty headers on my SS with hiflow cats. definite power gains at least between both of them. Also, DT's shorties and longtubes have neglible difference in HP gains on their website dyno graphs and the shorties have a little more low end torque. I'm happy with my shorties, they are less expensive, still ceramic-coated, they are not throwing codes (headers or cats) and dont' have to worry about clearance issues with the long tubes since my car is lowered. i have tuned so likely voided my warranty but shorties shouldn't if you haven't tuned. I'd go with the DT shorties and replace the stock cats with SOLO hiflow cats. The sound you'll get with the new cats is amazing. good luck!

http://www.camaro5.com/forums/showthread.php?t=91945

So again, no one cares to run the shorty's by themselves without a tune. Why is it that no one dyno's shorty's by themselves, yet quotes their website numbers as being true?

We appreciate the numbers from the SOLO's but I guess the shorty debate will continue.

[topgun1]

Originally Posted by axis

So again, no one cares to run the shorty's by themselves without a tune. Why is it that no one dyno's shorty's by themselves, yet quotes their website numbers as being true?

We appreciate the numbers from the SOLO's but I guess the shorty debate will continue.

well, I planned on tuning anyway (for the k&n intake, the magnaflow exhaust and hiflow cats also). I have numbers on the thread though without a tune also and signficant gains were shown. also, doug thorley's website dyno graphs are without a tune supposedly.

[ssmike]

OK this is the way I see it. Shorties by themselves are pretty much a waste of time for HP gains. Catbacks themselves really don't give you any HP gains either. It's all in the cats! If you put all 3 together, Shorties, high flow cats and cat back as a system you'll be within about 10 HP from LT's and high flows, WITH NO TUNE! This is just my opinion gathered from info I've seen on LT's and high flow cats from various vendors and forum members. The big point here is that with Shorties, high flows, and cat back you DO NOT HAVE TO tune, you won't throw a CEL code because the cats are in stock locations! I have DT shorties, Solo cats and Solo mach-X cat back and the sound is incredible and after I installed the cats, big difference in power! LT's may give you a little more power but they MUST be tuned to prevent CEL codes (unless you're the .5% that are lucky enough not to throw a code).

[axis]

Originally Posted by topgun1

well, I planned on tuning anyway (for the k&n intake, the magnaflow exhaust and hiflow cats also). I have numbers on the thread though without a tune also and signficant gains were shown. also, doug thorley's website dyno graphs are without a tune supposedly.

I'm not doubting your numbers in any way as them seem fair. I just question the MANUFACTURERS claims on shorty's alone. Shorties bolted up to OEM cats. No one seems to have any independent data to back up DT's or any other companies claims of 15+whp gains.

[2010 4 DW]

Originally Posted by axis

I'm not doubting your numbers in any way as them seem fair. I just question the MANUFACTURERS claims on shorty's alone. Shorties bolted up to OEM cats. No one seems to have any independent data to back up DT's or any other companies claims of 15+whp gains.

I always love posts where everyone wants to know how much power. I also would like to know but that does not stop me from purchasing a part. I figure guys have been buying headers for 50+ years and Hooker Headers never tested a header or told you how much power it would make. You could just tell by looking at it that it would flow better than your manifolds, and Hooker,Doug's and Headman were the only manufactures.

DW

[Ivan @ Southwest Speed]

Originally Posted by wbt

Shorties with, without or high flow cats?

These were with factory cats still installed on the car, no tune, stock airbox.

That way I could have viable, unbaised data.

You can and will see improvements with Hi Flow cats depending on which brand and all that.

These are totally independant tests that a customer, not a company paid for.

-Ivan

[axis]

Originally Posted by 2010 4 DW

I always love posts where everyone wants to know how much power. I also would like to know but that does not stop me from purchasing a part. I figure guys have been buying headers for 50+ years and Hooker Headers never tested a header or told you how much power it would make. You could just tell by looking at it that it would flow better than your manifolds, and Hooker,Doug's and Headman were the only manufactures.

DW

So you would go out and buy a PERFORMANCE part without knowing if it does what it says it does? You sir are the ones that the manufacturers LOVE. There's a set of splitfires with your name on them, somewhere.

There were PLENTY of guys that ran headers and confirmed they made power, back then. Also, it was widely known that the factory manifolds were pure shit, when it came to flow. Technology has come a LONG way since the 50's and 60's. It's too easy to measure the gains of part X to see if it works. The problem is, manufacturers want to sell you part X at any cost so fudging numbers or maniuplating testing procedures can easily be done. It's the independent testing that tells the true story. There is conflicting data on Shorty's and many would like to know the REAL truth. So far the only data that has been widely put out there is TSP's shorty install which showed they lost HP and TQ all along the curve. Now if you want to spend $500+ for the added PERFORMANCE because you think you can see that they are better, than have at it. For me, i'd like to see some real world testing. Unlike the old days when swapping to a aftermarket exhaust would net you large HP gains, some of todays cars are pretty well setup from the factory. Fortunately for us, the 2010 Camaro is one of those cars.