We need 10 people to throw $200, and they will be done in 2 WEEKS!!!!

I kid, I kid.

I was curious what people are looking for in the way of headers. I am familiar with the past on this subject and have no intention of repeating it.

First of all, we will not be collecting deposits of any kind and are not predicting a completion date. The money to get started will come from us. Once the template for each is started they will be served up as needed. We will only vary on number of cylinders, not FI to NA and cylinders. That would be ridiculous lol. Plus the point of this thread is to make a great all-around set for everyone, not specific to one exact motor.

I guess the first question is, do the majority want long tube, or short tube? Log is out of the question since that is what we are trying to eliminate. Maybe both? Then I wanted to get people's opinions on primary diameter, primary length, collector diameter... With good data to back up why. Driveability, racing, mixed... Basically what range are we looking to beef up.

The Exhaust Valve diameter I pulled for my motor (online) was 12.7mm so .5 ". Believe it's the same for M112. The M112 port size is dead on 1.5". I could not find volumetric efficiency so my calc's were just 75% for that. I expect NA's to be less and SRT's to be more.

With that data 4-1, bore, stroke etc. The calc came up with 1.39" primary diameter, 34.2" primary length, 2.5" collector.

The problem I have with this calc, is it is contradicting to what everyone says works. Everyone says that the primary diameter should be the same as port diameter or slightly bigger. With that knowledge I am thinking 1.55" primary diameter with a shorter length. Opinions?

Unlike most that just give you headers, we are going to add anti-reversion tubing at the end, just after the collector (except on shorty's). This helps the motor not take in and mix exhaust gases that it already pushed out. On a seperate note, my welder and I are going to play around with adding those after the x-pipe when we build my exhaust as well.

As it stands the first 2 sets are V8 sets and are called for. However, since I still have my V6 in my garage it will be very easy to make a set a port short for the V6's since spacing is the same.

I have shown my welder pictures of sets for other cars and he is very displeased with most. "They look like crap" are his exact words lol. He said that most manufacturers are using templates, that ours would be one piece for the primary's and minimal visible welds. The more welds, the more pieced together joints, the rougher the flow.

I'm guessing drawbacks of headers might be a CEL you might get for no primary cats and misplaced 02 sensors. We are thinking of leaving my secondaries, and making plug extensions for the post-cat 02 sensors, so that they are still placed as before, after a cat. In theory, it shouldn't be able to tell any difference.

Like I said, post up opinions, idea's, theories, and if ya got nothing to contribute, at least say if you would be interested or not and what type of style.

No idea on pricing but maybe 800-1500 for shorty's and 2000-3000 for long tube. He is still deciding exact material but will be a 300 series stainless for durability, cost and retaining heat. The first NA and SRT set's would be sold quite a bit under cost to people with the intention of before and after dyno's. Those people will most likely be one of the more senior members (post wise) for credibility.

 

Well the gains, the cost just prices them out. A lot of problems, mostly heat, comes along with headers as well. I ran them in the old days, but we had a lot of room in the old Camaros...I wouldn't be interested, but others may. I would think long tubes would be what you would want. Shorts tubes just haven't shown any gains...maybe 10 hp if you believe even that...good luck though...

 

Everythings speculation at this point for us specifically but guys on the MB forum have seen some pretty good gains from a good set. Some NA's on the other forum have seen a good 10whp increase over the whole band on shorty's I believe not tuned. Personally though I would rather have something to take advantage of what we have most of... Torque. I'm interested in hearing opinions on how though. The reason shorty's got mentioned is cost. Maybe you won't see a lot but mod potential would be better. $h** anything's better than the stock manifolds lol. The anti-reversion helps out a lot too on the long tube's.

Here's a thread for C32 shorty's that made 13whp 15 ft-lbs:

C32 Headers - MBWorld.org Forums

Based on that maybe a well thought out set of long tube's would net another 20-30 ish?

 

yeah, I am over there reading a lot as well, just don't say much over there. I personally wouldn't waste my $$$ for short tubes, but if someone could finally build a great set of long tubes, I would then consider the plug wire issues, the heat build up under hood issues, collector and exhaust issues...and, well, you get the picture...

 

Yeah, I here ya Doc. Temps could be addressed a few ways though. Shielding, coating, or wrapping. Maybe we could come up with bracing from the primary tube's and a shield or something that you bolt to the braces after you bolt the headers in? Maybe coat and shield but then cost plays a factor... Hmmm.

The plug extensions would be easy for me to pump out quickly. Take the stock plug - 02, cut it in the middle and add extensions with shrink wrap over the joints and the whole thing.

Another problem I see is the joint from the long tube's to the exhaust. Whoever buys will need a welder to weld it together.

Maybe my welder and I should look at complete header back exhaust kits?

My set will be long tube as well. He won't bother with shorty's unless it's at a business aspect to attract more customers.

 

Hmmm.. nice set of Chrome Harley heat shields cut to fit..

 

Something like that might be a pretty good idea! How good are they at keeping heat off you, say, at idle on a hot day? We might be able to figure out the material and cover more of the primary pipe's and then cut and fit where they merge?

 

I have bad news for header dreamers. On our supercharged, no overlap cammed engines, headers just don't do much. Most of the gains come from removing the cats. A N/A Crossfire will see more gains than a supercharged one. Ouch! I've been told my results are unusual but it is what it is.

Les

 

They really don't do bad.. Just a shot here to show how easily they would mount up. Just be a matter of finding some with the right curves really..

 

Les, what are the measurements on yours? Primary diameter, primary length and collector diameter? From what I understand the primary diameter with 75% volumetric efficiency should be smaller than our port size which is 1.5"... It sounds crazy but anything much bigger than 1.5" is loss.

Solid would probably do better too, I like the hoseclamps but maybe my welder can bracket the shield, fixed, just above the primaries with little contact... That way the clamp isn't touching the pipes as much, transferring all of the heat to the shield.

 

Tri-Y 1.75" primary's, 2.5" collectors. The lenghts I have to look up.

Les

 

I get short of breath looking at them, beautiful things. Then I look at the dyno sheet and my wallet and want to cry.

Les

 

I'm wondering if the primaries are too wide. I thought yours made power though? Or you lost boost but remained at the same power therefor could up the boost back to where it was and make power?

If you could find lenth that would be awesome. Also, how did it feel throughout the band as far as differences?

 

Maybe we can fix it Les. I have an idea to float by my welder.

 

We had a little problem with the software on the dyno and I lost some confidence in the results which in the end were 4 hp gain. So I went to the track and ran the same times more or less. I think I was a few hundredths of a second faster. Around 4 hp faster. We did a before dyno, an open header dyno and lastly one hooked up to the stock resonator/muffler. The 4 hp number is the difference from no cats and stock exhaust; then headers and stock afterwards.

Les

 

Are you true dual with an X-pipe? Maybe the headers are flowing great, but the exhaust is pinching too much to see it.

At the same time, open header may have been way too much overall flow.

 

The open header dyno was 7 hp higher than the final dyno. After the 2.5" collectors the dual tubes reduce to 2.25". They connect to the stock pipes, stock H pipe, into the resonator etc. etc. (stock system)

Les

 

I forgot about the 1/2 mile event I ran the same week the headers were installed. I ran around 1 mph faster, The conditions were a bit different but it all adds up to very little hp gain.

Les

 

I haven't looked at out cam profile so I'm assuming a lot. However, since I made no real power it's obvious to me we have no overlap to speak of. Impressive flames didn't shoot out of the open headers at the end of the dyno run. No overlap. Have a real detailed talk with the header designer, show him my photos and tell him my results is all I'm saying, before getting too far into this venture. Have him take a look at out cam profiles. If after all that he's sure, go for it and I'll rub a rabbits foot for success. All I want to know is how in the world are the E55 guys getting 70 hp from headers. (thats what sold me BTW)

Les

 

Well, I knew Les would chime in, since he has been there done that. Just so you know, about 45 min from me is a shop who have been building headers since the early 60's, from monster truck to some of the best drag racers in the world. Our problem is not just the fact we are not going to get a big return, but the room to even think long tubes. Their quote to me, and I love their work, was 2500 bucks. I would have done it for half that, but for that, I am doing a gear change in the rear end. As for shields, not even room to place your fingers in there let alone a wrench. So clearances are a huge issue, that is why I stated the heat issue as you are very close to everything trying to get down to where the collector will be. Once you are at the collector, then it is muffler shop time....no biggy there...

I will add this...in all my old days of muscle cars, headers were usually in the mix of mods we all did. They were always a pain from the burns we all had working around them, but they did add some HP....but 70 is ridiculous... Everyone car manufacturer in world would put headers on their performance cars if this were true. Think about that for a second. 20-30 is and always was max in our day...and I can't see that changing today with computers no less....