Topic: Any insight on dynatech long tubes?

[USMC0311]

Might have a possible line on some Dynatech Long tubes, and a high flow catted x-pipe. Haven't heard much about dynatech, so figured I would ask if anyone had any insight. Figure between everything else, and the headers and high flow cats I would get a custom tune from Nelson, or blackbear and call it a day for now! Any input would be appriciated!

[MyBigToy]

They're a quality and expensive product. I had them on my Vette. They are stainless and have hi-flow cats; my personal recommendation is to never buy anything except stainless or stainless and ceramic coated headers. In my experience mild steel rusts through from the inside in about 5 years on a daily driver.

You will lose some bottom end with long tubes vs. short tubes but that's made up in the mid range and especially on the top end. A tune should help some with the bottom end loss but you will not completely regain all lost. If you don't have one, get a cold air induction to help with airflow in - the same as the header will drastically help your airflow out. Buy all the mods you plan to do before you get the tune and inform the tuner of EVERYTHING you have done. Since you don't have a Predator tuner I'd recommend you pull the pcm and send it to the tuner; you avoid throwing a crank sensor code if you do it that way. That's what will happen if you let the tuner program another pcm and then you ship them your original to replace the one they provide you.

You should ask the tuner to turn off the OBDII codes for the rear O2 sensors as you will most likely get codes for them. I got the codes on the Vette but turned them off with a Predator programmer. The codes are thrown because the O2 sensors are further back than the stock location on long tubes. They are cooler for that reason and that causes them to read that the cats are not working efficiently - too much difference between the front O2 sensor reading and the rear.

Just a suggestion - you could go ahead and buy the headers and hold off on the pcm programming until after Bratfest. Main One will be there; he has installed a cam and that's something you could do that would be a cheaper alternative to a supercharger. That would also make up the loss on the bottom end with the correct cam selection. You could select the correct cam, install it, and then send the pcm in for tuning.

[USMC0311]

They're a quality and expensive product. I had them on my Vette. They are stainless and have hi-flow cats; my personal recommendation is to never buy anything except stainless or stainless and ceramic coated headers. In my experience mild steel rusts through from the inside in about 5 years on a daily driver.

You will lose some bottom end with long tubes vs. short tubes but that's made up in the mid range and especially on the top end. A tune should help some with the bottom end loss but you will not completely regain all lost. If you don't have one, get a cold air induction to help with airflow in - the same as the header will drastically help your airflow out. Buy all the mods you plan to do before you get the tune and inform the tuner of EVERYTHING you have done. Since you don't have a Predator tuner I'd recommend you pull the pcm and send it to the tuner; you avoid throwing a crank sensor code if you do it that way. That's what will happen if you let the tuner program another pcm and then you ship them your original to replace the one they provide you.

You should ask the tuner to turn off the OBDII codes for the rear O2 sensors as you will most likely get codes for them. I got the codes on the Vette but turned them off with a Predator programmer. The codes are thrown because the O2 sensors are further back than the stock location on long tubes. They are cooler for that reason and that causes them to read that the cats are not working efficiently - too much difference between the front O2 sensor reading and the rear.

Just a suggestion - you could go ahead and buy the headers and hold off on the pcm programming until after Bratfest. Main One will be there; he has installed a cam and that's something you could do that would be a cheaper alternative to a supercharger. That would also make up the loss on the bottom end with the correct cam selection. You could select the correct cam, install it, and then send the pcm in for tuning.

Man! I am tellin ya, I would never say this under normal cercumstances but....I love this guy! hahahaha! Man MyBig you are a freaking wealth of knowledge when to modding issues! If you ever have any question that has to do with the dealer or TSB's or anything of that nature do not hesitate to ask, as that is my area. Thanks again my frienbd for everything, man I owe you some serious beers at bratfest!

[bluedevil]

Man! I am tellin ya, I would never say this under normal cercumstances but....I love this guy! hahahaha! Man MyBig you are a freaking wealth of knowledge when to modding issues! If you ever have any question that has to do with the dealer or TSB's or anything of that nature do not hesitate to ask, as that is my area. Thanks again my frienbd for everything, man I owe you some serious beers at bratfest!

Yep

[Main One]

Dynatech is located about an hour south of me.  I've wondered in the past about maybe having a gtg there sometime.  Maybe they could give us a tour.

[USMC0311]

Dynatech is located about an hour south of me.  I've wondered in the past about maybe having a gtg there sometime.  Maybe they could give us a tour.

Now your talkin!

[Main One]

I'm running JBA shorty headers instead of dynatech long tubes for 3 reasons:

1.  Cost - my JBA's with ceramic coating cost I believe in the neighborhood of $600, vice twice as much for dynatechs.

2.  Loss of low-end torque with the dynatechs.  I believe that is probably more to do with them having a bigger diameter than with them being long-tubes vice shorties.

3.  The shorties fit in exactly where the exhaust manifolds came out from.  Just had to take out the manifolds and put in the headers.  With the long-tubes, need extra plumbing work downstream.

[USMC0311]

I'm running JBA shorty headers instead of dynatech long tubes for 3 reasons:

1.  Cost - my JBA's with ceramic coating cost I believe in the neighborhood of $600, vice twice as much for dynatechs.

2.  Loss of low-end torque with the dynatechs.  I believe that is probably more to do with them having a bigger diameter than with them being long-tubes vice shorties.

3.  The shorties fit in exactly where the exhaust manifolds came out from.  Just had to take out the manifolds and put in the headers.  With the long-tubes, need extra plumbing work downstream.

So how have the shorties worked out for you? i have for the same reasons been looking at shorties also, but like anything else you always have the neigh-sayers out there that say they aren't worth the money and all, but for me I don't really plan on doing anything too crazy with the avy anytime soon, and figure with a good tune shorties would work for now! so curious, were they easy to install? did you notice anything at all? Preciate it Main One thanks for your input, every little bit helps!

[bluedevil]

I have Stainless Steel Gibson shorties.  No problem.    The paasenger side was a walk in the park.  The driver side i had to undo the steering shaft.  No biggie.

[USMC0311]

I have Stainless Steel Gibson shorties.  No problem.    The paasenger side was a walk in the park.  The driver side i had to undo the steering shaft.  No biggie.

Ya kinda what I figured by looking at it. I had to do long tubes on my 72 lemans and if I can do that I can definatly do shorties on the truck!(if you have done longtubes on an old pontiac you know exactly what I am talkin about, especially when they are jet hot coated and you don't want to screw em up!) You find any noticable difference? My avy for some reason is real sluggish when you give her some gas in second or third, I want to remedy that! like I said before I figure shorties and a good tune would be noticable. Thanks for the input blue!

[Main One]

It took me 2 weekends to do it, primarily because I wasn't using the proper socket and rounded off one of the bolt heads where one of the manifolds tied into the rest of the downstream exhaust plumbing.  With the JBAs, I didn't have to mess with the steering shaft.

While they were supposedly ceramic coated, they are showing some rust.  However, I've got something like 150,000 miles on them.   

I'd say they gave more of an improvement than an aftermarket cold air intake.  Tuning afterwards does help.  They would affect Volumetric Efficiency and hence you would want to tune the VE table.

My AV isn't what I would call sluggish.  Tuning helps with that, by setting shift points by as much as anything else in mine and a lot of other cases I would say.

[USMC0311]

It took me 2 weekends to do it, primarily because I wasn't using the proper socket and rounded off one of the bolt heads where one of the manifolds tied into the rest of the downstream exhaust plumbing.  With the JBAs, I didn't have to mess with the steering shaft.

While they were supposedly ceramic coated, they are showing some rust.  However, I've got something like 150,000 miles on them.   

I'd say they gave more of an improvement than an aftermarket cold air intake.  Tuning afterwards does help.  They would affect Volumetric Efficiency and hence you would want to tune the VE table.

My AV isn't what I would call sluggish.  Tuning helps with that, by setting shift points by as much as anything else in mine and a lot of other cases I would say.

Right on! I appriciate the info. I just got some good news from my military education benefits and looks like I will have some extra $ so I am gonna grab a set of JBA's I suppose. I figure after that and a tune she should drive more to my liking. You used HPtuners correct? I was thinking about sending in my PCM to Nelson and have them do a custom tune for me, just seems like I will get more out of that than out of a predator or something of that nature. Once again thanks a bunch for your insight, I really do appriciate it!

[Main One]

Right on! I appriciate the info. I just got some good news from my military education benefits and looks like I will have some extra $ so I am gonna grab a set of JBA's I suppose. I figure after that and a tune she should drive more to my liking. You used HPtuners correct? I was thinking about sending in my PCM to Nelson and have them do a custom tune for me, just seems like I will get more out of that than out of a predator or something of that nature. Once again thanks a bunch for your insight, I really do appriciate it!

Yes, I use HPTuners.  I can let you see how it works Sunday at Bratfest.  Compared to one of the handhelds, you can definitely get more out of a custom tune, whether you do it yourself or have one of the pros like Nelson do it for you.  (I'm running my efans using a Nelson wiring harness.)  This is especially true as you put more performance parts on/into your engine, tranny, etc.

I've learned so much about how my engine, and engines in general, work by using HPTuners.  I figure I could learn even more, and even mentioned to the wife last night that I was interested in taking a tuning class called EFI 101:

http://www.efi101.com/efi101.html

They've got a class coming up on 10-11 October in the Chicago area that I am seriously thinking of signing up for very soon.  ($50 off (about 10%) if you sign up a month or more in advance.)  I figure it is sort like getting any other work done on your car - understanding what needs to be done and roughly at least how it gets done makes you a better consumer if you have Nelson or someone else do the programming for you.

Some people (like BlueDevil  ) are a bit afraid to jump in and play with HPTuners, but it really isn't rocket science.    

[MyBigToy]

Take the class, then you can teach all of us!

I hope we can spend at least a few minutes reviewing the basics of VE and MAF tuning. I've been reluctant to do this with only reading instructions @ HPT and PT.net. I want to make sure I know that I'm setting the MAF to "fail", etc. properly before I get started.

I've worked on most of the other parameters and spent quite a bit of time nosing around in the tables. Part of my problem is that I don't drive my truck enough to fill in the tables after making a change. It will be good to get some pointers from someone who has spent enough time with HPT to know their way around and can explain the info.

[Main One]

Take the class, then you can teach all of us!

I hope we can spend at least a few minutes reviewing the basics of VE and MAF tuning. I've been reluctant to do this with only reading instructions @ HPT and PT.net. I want to make sure I know that I'm setting the MAF to "fail", etc. properly before I get started.

I've worked on most of the other parameters and spent quite a bit of time nosing around in the tables. Part of my problem is that I don't drive my truck enough to fill in the tables after making a change. It will be good to get some pointers from someone who has spent enough time with HPT to know their way around and can explain the info.

LOL, I'm on my 162nd tune, just since installing my cam 2 years ago.  I've probably put around 300 tunes into the thing.  I've probably only played with about 1/4 of the parameters, maybe a whole lot less than 1/4.

Last winter, I decided to try to "fix" the problem that I had - my LTFTs were not stable over temperature.  I suspected that with the close proximity of my MAF in my custom intake to the throttle body and cone air filter, the MAF's sensors needed to be located more towards the perimeter rather than the center.  (It seemed in the colder, hence denser, environment, the MAF was not detecting low airflows very well.)

I modded my truck's orignal stock MAF to move the sensors, and did indeed conclude that there was a positive effect by moving the sensors, but not enough to fix my problem.  I decided then to try to fix the problem via software, specifically the IAT/ECT bias vs airflow table, which basically identifies how much IAT or ECT affects the calculated airflows.  (At low airflows, ECT comes into play more than at higher airflows.)  After 6 months or so now of collecting cold and warm data before doing retuning, I am now hopefully getting very close to having the problem fixed.  The proof of the pudding will come when I can get some really cold, sub-zero data this winter.  

For the last 6 months, between retunes, I've tried to collect data from the coldest mornings to the warmest afternoons in about a week's timespan, which here in the midwest are usually 20-30 degrees apart, although I have been "lucky" enough in the spring to get a 50 degree spread.

Anyway, will show details on Sunday.

[bluedevil]

Other things for ya to drool on

http://www.chevyavalancheclub.com/index.php?action=articles;sa=view;article=3