Only cuz it doesnt have a chipped Duramax in it!

 

I'm adding this little nugget of information regarding headers. I had ask Larry Meaux of PipeMax fame a question regarding long tube headers and short tube headers. Here is the question and answer.
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"1989TransAm wrote:
Larry, regarding short header exhaust system.

If one was to have the correct primary tube diameter, correct collector length and correct collector diameter would not a shorty header exhaust system approach a long tube header system?

Also when figuring the correct collector length what effect if any does a cone in the collector have for measuring purposes?

Answer:
Yes a "Shorty" Primary tube Headers can come close to another pair
of long tube Tuned Headers as long as the Collector Specs
are on the money !


Also when figuring the correct collector length what effect if any does a cone in the collector have for measuring purposes?

depending on the Cone Taper and Length,
usually .25 to .50 times the Cone Length is added to the Primary Tube
length... it gets complicated quickly as the amount of Taper/Length
can also have varying amounts of Temperature effects,
also depends on how much Cone heat is retained."

 

more than likely i'm going shorty headers and turbo over winter with new heads.....maybe C4 vette manifolds for a single turbo. not sure yet i have to plan this out and see if i can hit my goal of 600-650whp with my block/internals at 9.8 or so to 1 compression

 

Designing headers for a turbo is a different animal. I believe you will be trying for maximum exhaust velocity with low heat loss. You may want to consider a tubular K member for a lot more exhaust clearance.

Your car with that much power will really be an animal. The whole set up should be very streatable though.

I wonder if another camshaft would work better with a turbo?

From what Larry said I believe a well designed shorty header system will not be that far behind a long tube header system of equal design.

 

I'd wonder how much power i'd give up over these Hooker longtubes because it would be worth it to loose 10whp to gain exhaust clearance. Right now it hangs LOW

And if i did a turbo i'd probly swap the cam as well but i have to ask Bret if this thing will work for mild boost. It really doesnt look like a turbo grind with huge exhaust duration split and tight LSA.

I also thought about AFR 210's or the comp 195's and a bigger cam but i'm not sure i want to make the car any less streetable. Was thinking of trying a custom grind i created that should peak in the 6600 rpm range.

 

From what I have gathered you may be talking 10 horsepower with a well designed set of short tube headers versus a well designed set of long tube headers. Maybe nothing versus a well designed set of short tube headers versus an average designed long tube header.

According to PipeMax with shortys I need primary pipes of between 14 and 17 inches in length. I will be installing a tubular K member so this will be no problem to achieve even with a well designed collector with a cone.

The collector will be right below the two middle exhaust ports and the middle pipes will probably be around 14 inches long. The two outside pipes will be around 17 inches long.

Then most important is getting the secondary or collector pipe the right length and diameter. The length will be the job of the terminator box.

 

problem is if i go back to shorties i'll just get dyno don's since they are the only 1 3/4 header out there i guess unless there is a un smog legal version which is what i need anyway.

it wont be custom designed so the power losses may be more than i want to take

 

It looks like it may actually be easier to get an optimum collector length with a short header design because of the additional room. My concern is how much of an impact the short primary pipe would have regarding where peak torque and hp occur. Doesn't a short header push that point higher up the rpm scale?
Of course there's the same question. Where do you fit a resonator box?
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Are you going to have the opportunity to test an open header and collector as opposed to your full exhaust?

 

Quick question.
According to Pipe Max, which collector length contributes to building low rpm torque?

 

"Doesn't a short header push that point higher up the rpm scale?"

From my research here is what I have found if I have understood things correctly. Below peak torque long tube headers are better. Above peak torque there may be no advantage. That is based on everything else being correct.

So a well built set of shorty header can be better than a run of the mill long tube header. A well built long tube header would be better over all. So the bottom is line with a good set of shorty headers for our cars you may not be giving up all that much.

Just had an idea. Let's compare Orr's long tube header car with my Dyno Don short tube header car. We will use rwhp versus cubic inches. Both are 700R4 automatic cars with similiar stalls. Of course there are dyno differences but both are SAE numbers and the same type of dyno.

Orr made 392rwhp with 383 cubic inches. That is 1.023rwhp/cubic inch.
My car made 370rwhp with 355 cubic inches. That is 1.042rwhp/cubic inch.
Pretty darn close if you ask me.

 

Regarding the room for the termination boxes. I had given up on it until I noticed that a tubular K-member freed up a ton of room. I'm also going with a Canton Oil pan to free up some more room. I will take pictures of what I will be doing.

 

What I really want to see is some data comparing full exhaust with open headers. Dyno simulations show hp increases along the lines of 10%. 412 chp vs 451 chp in my case. That to me is worth pursuing.
I'm looking forward to your terminator box construction. That would be the icing on the cake.

 

Hey chaps we are finishing up that 92' rs with the 4" terminator tube. We should have some pics soon and some dyno numbers to compare shortly after that. We had a few set backs but we are getting close to having her done. We'll keep you guys posted.

 

yes i will be adding a cutout here sometime whenever i feel like taking the exhaust off. I hope to add it and then take it to the dyno to finalize the new MAF sensor tune, and then i'll do a cutout open run on the dyno

then i will track the car again.

I may order the cutouts tomorrow

 

Orr if posible try to get the cut outs around 18.4" from where the primary tubes end in the collector. That should get you the maximum benefit. Let me recheck PipeMax.

The best locations are 18.4" and 36.8" from the end of the primary pipes.

The worst locations will be 27.6 and 55.3 inches.

 

I peak at roughly 6300 and would like to boost the 6000 rpm range due to my gearing not allowing me to cross the line any where near peak hp.

i think i'll beable to reach near 18 inches but depends

 

"Hey chaps we are finishing up that 92' rs with the 4" terminator tube. We should have some pics soon and some dyno numbers to compare shortly after that. We had a few set backs but we are getting close to having her done. We'll keep you guys posted."

I'm looking forward to the results.

 

Which offers the best low end torque? I don't have the grunt of the 383 and good use a boost around my stall speed.

 

In Orr's case the 18.4 gives the best all around performance. The 36.8 gives the better low end torque. We may not be talking much of a difference.

 

my torque output seems low for a 383, i could use more. BUT 36.8 would put me at the y pipe almost i believe. i'll have to shoot for 18

tomorrow or maybe sunday i will try to install the subframe connectors finally poor car

while its in the air i'll take measurements on the cutout placement. i want electronic ones but can not justify 300 bucks for the pair

 

I designed my y-pipe to be removed easily at the track. Isn't that easy. Anything underneath these lowered cars and you need a full set of jack stands.
The cutouts would certainly make things effecient.
As far as science goes, do you think the cut outs would behave sufficiently like " a substantial change in cross sectional area " even with the balance of the exhaust still hooked up?

 

The exhaust will find its way thru the lowest pressure spot. Any pin hole in the exhaust air will leak out as exhaust is slightly higher pressure than atmosphere.

So with the cutout available, 90% of the air will flow outward i think. So it will act like open end pipe

 

Been thinking about that.
Have you calculated you dynamic c.r.?
Couldn't find it in your old threads or all the info to figure it out.

 

Couple of my thoughts on a cutout. If you already have a good free flowing exhaust system I don't think you will gain much as you have already eliminatied much of the back pressure.

However by the proper location of the cutout you can gain from wave tuning. This can be quite a few horsepower. You just have to locate the cutout in that sweet spot. Now it might also be possible to loose or not gain any power by installing the cutout in the wrong locations as indicated in my response above.

 

Dynamic is around 8.3 to 1.

yes i'm not going for more flow, i'm going for wave tuning with cutouts. I'm sure abit mor flow helps since all that piping length kills some flow in the long run but the wave tuning will help alot

 

I agree with that. I think there is a little to be gained from the flow but most will come from the wave tunning in your situation.

 

I've been reading through this thread and was intrigued enough to get PipeMax for myself.

My engine build is a 383 LT1 engine.
The hedders I have are Pacesetter LT's.

According to my engine specs PipeMax tells me I want a collector that is either 16.4 or 32.8 inches.

I will be using a dual 3" exhaust system so the pipes are the same size as my collector.

Here is the question.....

Do I want to put the "resonator", or whatever is going to be used for the pressure change, right after the specificed length for the collector?
Also, what specific muffler or resonator is best?

thanks!!

 

Yes but you want about two inches of that 16.4 inch collector in the terminator box. Same with the 32.8 dimension. The problem is finding enough room for a terminator box. You will need on at least 383 cubic inches on each bank. What ever you do, do not build a square box. I see that Spintech has a lot of oval tubing. That may be the way to go for some.

I wonder if Spintech has taken over Dr Gas's operation?

 

383 cubic inches on each bank after the collector?

I dont see that as being possible under the car....
hmmmm.....

Could I just put a muffler at that point and then dump it?
How would that work?

 

That is the problem and why most don't do it. I have figured out a way to do it with a tubular K-member, custom oil pan and a special rear transmission mount. However this will not be a true dual exhaust system. It will be somewhat along the lines of the factory routing.

 

I am wondering how it would work if I went with the 32.8" resonance.

Would using a 3" glasspack mess things up? I can see using a glasspack on each side, and then dumping it at 32.8" as something easy, though loud.

 

Different mufflers react in different ways.
A glass pack style muffler will react the same way as a straight length of pipe.
If you were to attach an appropriately sized glass pack at the end of the header, your collector length would be the total of the header collector plus the length of the muffler.
A typical chambered muffler like a Flowmaster or Dynomax case style will behave like the open end of a pipe. The exhaust pipe entering the muffler from the header collector can now be considered the overall collector length.
It's important to note that installation details appear to be significant such as how the collector extention (if any) enters the muffler case. In some instances an empty muffler case of sufficient size can be used as a termination box to achieve the open air effect. It was also suggested here that a length of round or oval shaped exhasut pipe could be used. Minimum eight times the volume of one cylinder per bank is required. Don't lose sight of the fact that you still have to have enough exhaust cfm to satisfy your horsepower needs.

 

A few words of inspiration for those who are still pursuing the resonator box idea.

SOME HEAVY-DUTY QUOTES FROM ENGINE MASTERS WINNERS

John Kaase: "I used a straight-through glass pack muffler design specifically because of the high-flow they can deliver. My dyno testing left no doubt as to how important collector length was and that a straight-through glass pack contributes to that length. By getting the collector/muffler length right, which in our case was about 40 inches, the torque at 3,500 was increased substantially. That gain is probably what won the Engine Masters deal for me the first time. I have seen an incorrect length along with less than the critical minimum flow cost 40 hp. Short change efforts on the collector/secondary and it will short change you."

Joe Sherman: "If you are building a serious performance system, then assuming you have a near-optimal header set-up, the place that is most critical when it comes to avoiding power loss is from the collector back. Also, don't be fooled into thinking that big tailpipes contribute to power. In all my years of dyno testing, I never have seen that work. For me, the straight-through Magnaflows when used as part of the collector length, show only very small losses in power over an open pipe. It's all about the right length and sufficient flow. I have seen mistakes in this area cost 85 horsepower."

85 horsepower!

 

yeah i wanted to do something like a straight thru dumped before the axle at 72 inches. I think that was the next best length. 32 would dump half way down the car and look bad i think

 

What effect does an x-pipe have?

 

I may build a track only muffler setup. A couple of free flowing glasspacks at the appropriate length and go racing ( or the dyno I suppose). Ground clearence wouldn't be so much an issue for the short term and the right set up could offer adjustability with various extentions on the muffler tips. Once the best overall performance is found a tuned collector/terminator box system could be built with a more traditional muffler and location.

 

An x-pipe or balance will always contribute to a quieter vehicle. In many applications in helps in producing a little more hp. I haven't read any published articles as to why.

 

I meant effect with the waves. My exhaust bends smooth and I use ultraflo mufflers, straight through type, dumped at axle. So I'm wondering if the x-pipe acts as the termination or the end of the muffler.

And its loud as hell, could be the 9 psi on a 110 lsa cam though.

 

I think I am going to try having the mufflers 32" down the pipes....

Is there a reccomended magnoflow muffler? Been looking at them on Summit and I cant find too many details.

 

Magnaflow makes a very good muffler of the straight through design. It would not work for a terminator box. As strange as it may seem Flowmaster makes chambered mufflers that might work depending on the size.

Now TheBadazz does it with larger diameter pipes. I think that is the way to go for most. He is going to post the results shortly of one of his cars with that modification.

 

for x pipe, i dont think it will hurt anything if its before the terminator boxes, but the proper design was to include a balance line between both banks' terminator box

so its more an H pipe now. thats the way i understood it

 

Hmmm, I might follow your numbers and run and dump a section off the collector, sans balance though. Before I go and hack up mine to install cutouts..

 

A blown 383 and you want more? I can dig it.
As far a pressure waves and tuning, I've read nothing that says a balance pipe contributes in any way. It's a significant change in cross sectional area that creates a reflected pulse. A balance pipe dosen't offer that. It will help to make the system quieter.
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A typical baffled muffler will behave like an open pipe with respect to reflected pulses. Put that on the specifed length of collector extention and that's your tuned length. The muffler dosen't add to the collector length.
Put a glass pack on there, and the glass pack adds to the collector extention length.
Any muffler you choose still has to have enough cfm capability to support your hp target.

 

i hope to boost mine you always want more. I want a turbo so the exhaust gets toned down some

 

My engine is finished, it just needs the exhaust on.
Its a 12.2:1 LE3 383 LT1 with all the goodies......hoping for about 450rwhp.

Is it 2.2 cfm per horsepower? Then I'd need something like 1100-1200 cfm

 

Dynomax ultraflo's work well..same with magnaflow straight thru rounds. they support enough if you go single 4", or else true duals will be enough flow

 

I found some free info at headerdesign.com. Their program said 13.2 collector length, but the program only supports 620hp.

This picture states, I think, that the crossover will affect the collector end.

 

What series Flowmaster flows well?
Their website is lotsa advertising.

I'm gonna try for the muffler at the ends of the collectors.

 

It appears to me that they intend an open exhaust at the collector end and then also have the point where a full exhaust would carry on including a crossover. The crossover isn't part of the open exhaust setup.

 

I posted this in another thread.
Might be something useful.
I haven't found any other data.

All tests via an independent lab
All tests @ 15” wc

2 “ Straight Pipe 283 CFM This is very close to the 115 cfm/sq. in. test standard.
2 ¼ “ Straight Pipe 365 CFM
2 ½ “ Straight Pipe 521 CFM

2 ¼” Typical Bent tailpipe 268 CFM
2 ½” Typical Bent Tailpipe 417 CFM

2 ¼” Inlet/Outlet_ Glass Pack Tips- No Louvers- Smooth 274 CFM
2 ¼” Inlet/Outlet- Glass Pack Tips-Louvered 133 CFM
Same as above set for reverse flow 141 CFM
2 ¼” Cherry Bomb 239 CFM
2 ½” Cherry Bomb 294 CFM

2 ½” Inlet/Outlet Dynomax Super Turbo 278 CFM
2 ½” Inlet/Outlet Ultraflow Bullet 512 CFM
2 ½” Inlet/Outlet Gibson Superflow 267 CFM
2 ½” Inlet/Outlet Flowmaster ( 2 Chamber) 249 CFM
2 ½” Inlet Outlet Flowmaster ( 3 Chamber) 229 CFM
2 ¼” Inlet/Outlet Thrush CVX 260 CFM
2 ½” Inlet/Outlet Maremount Cherry Bomb 298 CFM
2 ½” Inlet/Outlet Hooker Aero Chamber 324 CFM
2 ½” Inlet/Outlet Hooker Max Flow 521 CFM
2 ½” Inlet/Outlet Borla Turbo 373 CFM
2 1/2" Inlet/Outlet Magnaflow 284 CFM


Standard OEM 2 ¼” Inlet/Outlet 138-152 CFM
Standard OEM 2 ½” Inlet/Outlet 161-197 CFM
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Remember.
2.2 cfm of muffler flow per horsepower for zero loss due to backpressure.