I just dyno tuned my 98 A4 today with the Dynatech SuperMAXX header package installed. Overall peak gains were approx 10rwhp and 20rwtq. Differences under the peak showed average gains of around 20rwhp/rwtq

These numbers are with my converter unlocked. My mods are in my signature and the only change from the before/after dyno pulls was the addition of headers and some slight tuning. As you can see I was running a little richer in my baseline pull. Overall I am happy with the results. Here is the graph:



:cheers:





[Modified by bgood, 12:39 AM 5/16/2004]

 

Thanks for the info. I am still deciding on my H/C, LS6 intake, and longtube package for next year. The Dynotech headers are very interesting to me. :yesnod:

 

Maybe I'm on dope, but it looks like your AF is right on in your after pulls. Most guys here tune for 12.6-12.9 on a Dynojet, as you will lean out more on the street. As I read your chart you were slightly richer before your install/tune, but not out of the power or saftey zone.

Glad you got it done and are happy.

Cheers! :cheers:

 

:iagree: A/F was richer on the 1st pull and good on the 2nd pull.

 

Oops... I meant that the other way around. Thats what I get for getting ahead of myself. I was posting this while practically walking out the door for a road trip to NC. I need to pay more attention to which graph goes with which pull.

 

So, are you happy with the results? In your other thread you stated you were interested in a comparison between the Dynatech and the LGM headers. http://forums.corvetteforum.com/zero...=767340&page=3

From the other posts I have seen on here, the LGM seems to produce around 30hp gains. Based on your results, would you recommend the Dynatech or LGM's?

 

Becareful about comparisons between different parts on different cars. For a back to back test the test should be done on the same vehicle and at the same time of day. The tune should be as close as possible as well.

Its too bad your baseline dyno pull Air Fuel was not the same as your dyno pull with the new headers. Which dyno pull was each graph taken from...was it the first, second, third...baseline pull. Usually the 2nd and 3rd pull is the strongest. Just curious as I was considering these headers.

 

I really am not concerned with dyno numbers, too much variance. My question is; Does the car feel faster? If you can feel it you got 10% more.

 

i was really hoping you were going to see more HP. That explains to me why at the track my car didnt pick up. My car is still untuned but even so, i was hoping you'd see 20+ RWHP. I wonder what an auto does to the HP reading? Maybe a few HP down from a m6 car?

and to boot the red runs (I assume these are after header install) is leaner so that might account for some of that HP too.
Dave


[Modified by TT_Vert, 10:07 AM 5/17/2004]

 

I can understand that....let me just say everytime I have put a set of headers on from Stock the car has been faster by SOTP meter. Headers are a great mod expensive..but the more performance mods one makes to the car the greater the benifit is from the header. So on a stock car it is going to make a difference...but the as you move more air into the motor..the more needs to be moved out.

As for dyno numbers they are significant for dialing in the tune to show what the optimized performance numbers are as a result of Air/Fuel and Timing..and yes an A4 is typically less than an M6 on the dyno. Most A4 cars I have seen on the dyno in stock form range between 280-290rwhp. Whereas most stock M6 cars range between 290-305rwhp. From low to hi the diferrence between 2 cars at the opposite ends of the range coule be 25rwhp. So there is some variance. Thats why comparison test need to be conducted on the same car...that way there is less variance.

 

I think the numbers people have in their head about the LG Headers are somewhat inflated also. (been looking at too many dynos out of Texas) Take a look at these links and compare them against other LT header systems and you will not see much of a difference. Marketing goes a long way...

LG w/no cats before/afterhttps://www.corvetteforum.com/events...o04/dyno31.jpg
01 A4 before/after LG w/no cats http://forums.corvetteforum.com/zerothread?id=314393
Another before/after LG w/no cats http://forums.corvetteforum.com/zerothread?id=181201

A4's have a lot of other factors to consider (gearing, converter, etc) Here is another dyno graph of my system before/after with the converter locked. Disgreard the blip in TQ at the beginning of the baseline dyno. It's reporting a false peak rwtq number of 352rwtq on the baseline. It should be around 325rwtq peak... Again this is on a 98 with 116k miles:

 

Yep I agree. My concern is not the numbers from the dyno, but SOTP feel.
I decided to go with headers because like you said, they add to every other subsequent mod.

 

The baseline pull was the 3rd pull and the after pull was the 9th pull. The first couple post install pulls I was getting some KR which we discovered was the AC compresser turniing on and off. Once I turned off the AC we ran some pulls to log KR and then made some adjustments to the A/F ratio and timing. The difference between the first few pulls and the pull shown on the dyno graph were minimal. Now I could post my worst baseling pull and my best post install pull and get some really outstanding numbers, but I'm trying to give the most accutare representation I can. The biggest factor I did not have any control over was the weather. Here are the contidions for both before/after pulls:

Run 003: 83.95*, 29.28 in-Hg, Humidity 15%
Run 014: 90.48*, 29.28 in-Hg, Humidity 20%

 

SOTP.. :D There is a bit of difference. The car pulls much stronger now and I am able to notice a nice increase in low end torque.

 

well temp and continous dyno runs will also heat soak the engine and bring HP down some. That could account for some HP loss too

Dave

 

Yeah that was what I was trying to get at...I should have broke it down in more detail.

Normally..(at least when I have done dyno pulls...and I mean when I have ran the dyno or observed) the first run is not done with the car at the normal operating temparature...between 185-200*. So the first pull will be a little less and the second and third pull will yield the highest pulls. As more pulls are made the motor gets hotter and thermal efficiency is lost...it actually works both ways..to hot or to cold both equal less power...don't confuse with cooler IAT..we are talking operating tempatures and the effect on HP numbers on the dyno.

In order to get the tests more accurate all conditions must be as equal as possible. Unless the weather is real consistant all day...many times dynos in the morning will be different than dynos in the afternoon. Sometimes its better to take the Correction factor out and just use the standard measurement. The outside ambient looks close enough for the test...however it looks like there were a bunch of dynos between the two...should have taken a break, let the car cool, and ran another separate 3 dyno pulls with the new headers. That is the way I would have done it to insure accuracy more than numbers. However on a stock LS1 and LS6 I have observed a 8/15(ls1) 10/20(ls6) hp/tq change over stock exhaust manifolds....except for after 2001 when the the mid-pipe and higher flowing cats changes were made to the exhaust system....which meant that less gains from headers on stock applications were seen.

If you put FI, Stroker, Heads & Cam..then the benefit from headers, and less exhaust system really start to shine and make it evident of the performance factor with use of headers.

 

After reading the other thread, and the tuning done on this car before and after the Dynatech installation, this car seems like an ideal candidate for the LG header comparison test for a near stock car. :yesnod:

 

:iagree:

 

Low end torque. Thats what I'm after.
If I could just figure out a way that I like to route the o2s wires, I'll be able to see first hand.

 

OK, I appreciate your reply, but I am interested only in cold hard data and (no offense) not opinions about inflation.

Thanks for posting those dyno graphs, I would rather compare those to others I have seen on on the Kooks, Dynatech, and LGM's for clarity.

It still appears though that, with personal biases aside, the LGMs produce more power.