skinny z

Do you not attribute (some of) the new found power above 5500rpm to the ETB (I tired of typing exhaust termination boxes)? This is exactly what they are supposed to do. Increase the VE and torque production will follow.

1989GTATransAm

iTrader: (3)

"Do you not attribute (some of) the new found power above 5500rpm to the ETB"

Could well be. I am waiting for the club to have another dyno session before passing judgement on the ETBs. Let's just say they did not hurt a thing power wise. I have been burned to many times over the years.

As you know I am working on a new intake system as the one on the car is not optimized for the new engine. It was great on the old motor but for this motor it is a little on the small side.

Orr89RocZ

iTrader: (20)

So a combination of the intake being abit restrictive and the old converter were probable causes to limiting the motor's power potential to 5500 and beyond? The ETB's and new converter helped gain some of that back?

1989GTATransAm

iTrader: (3)

Hi Orr

When I first installed the new motor I noticed it tended to flatten out on power around 5500rpm and up. Gobs of power below that. Seeing as the motor still was not tuned I thought maybe it was running out of fuel or going lean. Well we put it on the chassis dyno to tune it and sure enough the motor was pretty much flat lining above 5500. Some tuning we did, did nothing to solve the problem so we called it a day. At that point I figured it was the intake manifold choking the motor.

That and a couple of other things started my quest for a new intake manifold. I got to thinking about the converter even though it worked just fine on the other motor. I emailed the dyno results up to Dave at Yank and he said I need a converter that grabs sooner and suggested we convert the PY4000 to a SS4000 as that would better fit my situation.

So in the meantime Don installed a stock converter in the car and while we were at it installed the new headers and the exhaust termination box. As posted above Kevin re-tuned the car in anticipation of the next dyno run. I wanted to make sure there was enough fuel available to cover any horsepower needs and the reason for 58psi.

Well, I took the car out for a little spirited driving and it pulls right up to 6500rpm with no let up whatsoever. So whatever was causing the motor to stall out at 5500rpm is gone. We will dyno tune it the way it is and then re-install the reworked converter.

Orr, I can't imagine driving your car with all the power it has. Mine is enough for me.

Oh, regarding my intake manifold now on the car. PipeMax says the pinch point should be 2.35in/sq for ideal velocity. The plenum opening should be around 3". The pinch point now is 2.2in/sq and the plenum opening is 2.68". It was designed for a 355 motor up to 6300rpm. This is a 369" motor designed to go 6800 or more. I can easily rework the First/SLP runners to the new dimensions once I have them off the car. However I also want to experiment with "wave" tuning with the new intake system.

Orr89RocZ

iTrader: (20)

Mine's too much for street trim at the moment...need some sort of traction control to use this car But I miss my high rpm 383...buzzing to 7K is fun

skinny z

It's called your right foot!

1989GTATransAm

iTrader: (3)

We have some dyno results in. One thing for sure the mid range really fattened up. I believe this is due to the exhaust termination chambers. As it stands I believe the current intake system is holding me back on top. It is only 2.2CSA where the intake meets the head.

It needs to be around 2.61CSA going by the calculations. As some of you know I am working on a "large" long tube runner project to replace the current intake system and should cure the power on top and fatten the mid range even more.



See post 3 in this thread: https://www.thirdgen.org/forums/tpi/...o-results.html

Orr89RocZ

iTrader: (20)

Holding you back and you still put down 420? Haha thats gonna get interesting when you put a real intake on it.

You should take that setup to 6800 rpm...it looks like its just starting to peak at the end of the run, i bet it hangs on a good 200-300 rpms after. Shift by 6800

skinny z

I'm happy to hear you say that. I was wondering if the other mods would sort of blur the effectiveness of the new exhaust.
Would you say that the new found torque falls within the predicted RPM range of the tuned collector length? If I recollect you used the PipeMax program in your calculations.
Nice numbers. Congratulations again.

1989GTATransAm

iTrader: (3)

"Would you say that the new found torque falls within the predicted RPM range of the tuned collector length"

It actually exceeded it to my amazement. The best I did on the engine dyno with this motor, long tube headers and the Victor Jr intake was about 470 torque. With the power it made the torque was virtually right on what PipeMax said it would be. So that part fully coincided.

Now that the motor is in the car with a different intake system using the 20% loss with an unlocked automatic transmission car I am up around 520 torque. With a 17% loss I am around 500 torque. I have to attribute that to the longer intake runners.

The mid range is way up there. I can only imagine what the high flow long tube runner set up will do.

Orr, I have no doubt your old combination would have exceeded 400rwhp. Also Dyno Don was having trouble with lifting his foot at the right moment on the dyno to reach the rpm we wanted. The motors were climbing pretty fast so that is why he let up maybe a little early. I think I will program into the transmission controller a 6650-6700rpm shift point. With the "shift extension" on the Yank SS4000 torque converter there is really no need to spin much higher.

1989GTATransAm

iTrader: (3)

One more thing I just remembered. When the motor was run on the engine dyno the headers were uncoated. Since then I have had the headers coated inside and out. So there would be more heat retention and the exhaust gas velocity would be higher. That would also make a difference. Bottom line the exhaust termination boxes do work as advertised. IMHO they do simulate an open exhaust system.

skinny z

That's the kind of news I was hoping to hear. Now if it weren't so difficult to build a terminator box system on a lowered 3rd gen with LT headers then I'd be off to the races (so to speak).
I will experiment this season with cut-outs placed along my fabbed y-pipe. I should be able to calculate the secondary lengths needed (using Pipe Max) and if that works (and I suspect it will, probably to the tune of 1/2 a second) then I'll work on developing a termintor box system that'll fit along the trans tunnel. I've seen the set up on a C4 Corvette. If there's room there, there should be room anywhere.
Thanks for going through with the experiment and posting the results.
That's why I like this forum.

Orr89RocZ

iTrader: (20)

Question is, how much did these help over a straight section of pipe where the boxes are now? Any chance to fab up a quick test pipe section to take out the boxes and redyno?

1989GTATransAm

iTrader: (3)

Actually they are already made up and ready to go. After the Los Angeles Invasion race I want to have the exhaust termination boxes ceramic coated with a heat barrier. So while they are off and the straight pieces are in their place one could do that. However my latest focus is on the new intake system.

skinny z

Now THAT would be the ultimate in R&D.
However forgoing another dyno test, if the boxes are truly effective, you could undoubtedly feel the difference in the seat of your pants.
If possible another trip to the drag strip would provide some results as well. Before and after the "invasion".

Orr89RocZ

iTrader: (20)

Hard to say. + or - 20wtq isnt as noticeable SOTP on a 400wtq car as it would be on a lower powered car. I picked up about that much on my 383 and really didnt feel all that different but it trapped 2 mph faster at the track

1989GTATransAm

iTrader: (3)

There is no doubt in my mind it works. Also the coatings on the header helped. PipeMax calls for 467rwtq with my combo on an engine dyno. The best I did without cooling off the motor for the final run was 466rwtq using the same headers. With the long tube headers on the engine dyno the best was 471RWTQ.

I have never even come close to that RWTQ number before. I think the best I ever did was 370rwtq. Even the last one with the new motor was around 370 something. However there were other issues so I don't count it as being valid.

The exhaust expansion chambers are supposed to duplicate and open exhaust system. That they do.

skinny z

We had discussed that the idea of a 20% increase would be something to talk about.
I understand that several modifications were made and it's not black and white however from an original 370 ft/lbs to 460 plus is significant. And beyond 20%.
There would be an even greater benefit on a vehicle that had a crippling exhaust to begin with. (yours truly in particular).

1989GTATransAm

iTrader: (3)

I did not state that right. The 370 was on the chasis dyno. So was the 417. The 470 was on the engine dyno and was for comparison percentage wise. As you stated the gain will depend on how good your exhaust system is to begin with.

skinny z

Makes a little more sense. Nearly 30% is quite an improvement. Still though, from 370 to 417 is still no mean feat. How do the two torque curves compare?

1989GTATransAm

iTrader: (3)

How do the two torque curves compare?

They are on my lap top. However I can tell you there is no comparison. The new one is way fatter.

1989GTATransAm

iTrader: (3)

One more thing I did different from the last dyno pull was to increase the fuel pressure to 4 bar from 3 bar. I know this really helped at idle but I don't know what effect it would have at wide open throttle. Maybe better atomization?

skinny z

That's what it's all about.
I hope I have the opportunity to experiment this year at the track.
Last year was a complete wash out with not having rebuilt my old 350 till late in the season. So much for my grand plans.
Be sure to post your results from the invasion.

1989GTATransAm

iTrader: (3)

"Be sure to post your results from the invasion"

Will do. It is about 60 days away.

skinny z

I never did follow up on your results.
I am still researching and have to ask you what the LCA was on the cam you had been doing your testing with. That testing being the time this thread was still active.

skinny z

More specifically, the amount of overlap.
Have you posted your cam timing somewhere or is it a secret(!)?

1989GTATransAm

iTrader: (3)

Hahahaha. No secrets here. At the invasion I went 11.57 seconds in the 1/4 at just under 116mph without finding the time slip. 60' was 1.57 seconds.

Camshaft is on a 113 LSA. Intake is installed at 109.5 degrees. Specs are 233/233 @ .050" and 280/280@ .006". With 1.65 rockers the lift is .594/.594. Intake valve is 2.08" and the exhaust valve is 1.60".

The exhaust termination boxes are currently off the car because I went in for the bi-annual smog certification and did not want to take any chances. We will dyno it with version 2 of the long tube runners without the boxes and then put the boxes back on and dyno it again and see what the difference is. Just waiting on room at Dyno Don's shop.

I am trying to see if I can cut a 10.99 time slip. That might be tough one to do. One of the reasons for me trying out the different intake systems including my new TPI Cross Ram which is under contruction.

skinny z

11.57 at 116 mph. I like it.
Thanks for the detailed cam specs too. I have continued to develop my own exhaust termination box (ETB) project and have been doing more research. How it's related to cam overlap is very interesting. It got me to thinking how your (smog spec) cams typically carry a wider LSA and a resulting smaller degree of overlap. That directly impacts the effectiveness of the ETBs. Tests show ETBs are particularly effective when larger amounts of overlap, either through long duration cams or tighter LSAs, are used.
This racing season may provide some interesting analysis if I can ever recover the steady baseline I had established a few years back.

1989GTATransAm

iTrader: (3)

You are correct. However I feel that I am getting some benefit from them. That is one reason I used PipeMax to design my exhaust to help maximize the timing of the exhaust during the overlap period. My current VE is in the 104 to 105% range going by PipeMax. I am trying to up that to around 109% if I can. I now have better flowing heads installed and I am trying to improve the intake system in order to do so.

Edit: By the way my cam has 54 degrees of overlap.

Mystyk_Wynds

Ok I need to ask some experts in this field a couple questions. I'm designing one as I write this, its I'm using stock routing, as the car is bone stock except for headmen shorties. I don't have the finances to purchase all this software every has for intakes and exhaust and computers.
Now accoridn to the online programs that I have found, I need a secondary of around 39-56". The secondary pipe is 2 1/2 stepped up to 3" to the cat muffler and back to 2 1/2. Collector is roughly 4" Long-4"dia to 3". I intend to add an additonal 6-8" 3"dia to 2.5"dia. Sot he collector is totaled @ 10-12" long.
Now with the PWB, can both secondaries dump into one box with one 3" outlet? Does the box have to have a divider? IE: two boxes mated together, one for each secondary?
Also I wanted to move my peak torque up to around the 4k rpm range. Is there anyone who can help with these specific calculations? I just want to make sure I'm semi right before I start bending pipes.
Now the location is intended to be in the same area as the cat with the cat. Now it will have an x pipe additionally with bell mouth adapters on the muffler and PWB. As indicated in car craft and vizard, this increases general torque.

1989GTA, I would really like your help with some things, Especially since you seem to be revered as "The Man" here. An so your posts and thread indicate that.

Mystyk_Wynds

These quick pics would be what I'm asking about.
I guess the PWB5 is one I have to ask if that would affect anything?
It would allow for a smaller height in theory.

1989GTATransAm

iTrader: (3)

"Now accoridn to the online programs that I have found, I need a secondary of around 39-56". The secondary pipe is 2 1/2 stepped up to 3" to the cat muffler and back to 2 1/2. Collector is roughly 4" Long-4"dia to 3". I intend to add an additonal 6-8" 3"dia to 2.5"dia. Sot he collector is totaled @ 10-12" long."

Something is amiss. I use a program called PipeMax to determine my exhaust system needs. As a guess I would think you need a collector of maybe 17" long or so an 2.5" sounds good. The collector measurement starts where the primary pipes of the header end.

As to the exhaust termination box(es). If using one it needs a volume at a minimum equal to twice the displacement of your motor. If using two each needs at a minimum to equal the displacement of your motor. The termination box needs to be at the end of the 17" collector pipe with around 1" of that sticking into the termination box. From the exit of the termination box it can go to a catalytic converter or two depending on what you are using. I would say any of those you posted would work as long as the cubic inch is correct.

Mystyk_Wynds

Ok I was under the impression that a PWB needed to have the minimum volume of the number of cylinders that flows into it. IE one collector dumping into it a PWB it had to have volume of 4 cylinders. If both collectors dumped into one box It would have all 8 in volume.

Second I thought that secondary length as stated here was more important than collector length. As such you would tune the secondary length and end them into a box, especially on a road car. So the tuned length is half way up the collector to the end of secondary into the box.

One of the calculators I used is Wallace. That gave me the secondary length of 56". i would like use "oval-ish" tubing, would allow me to lay things flatter, Only thing I can think of is to flatten either 3" or 4", Not sure but don't think that would work very well.

Also in that program is there anything relating to secondary length? I'll post up my cam specs if that will help.

overlap=-24;, Dur Int/Ex=207/213;, CL Int/Exh=110atdc/120btdc;, Lift Int/Ex=.415/.430 (Not sure of any duration other than this)
Int VO/VC=-6.5 btdc(-=atdc)/33.5abdc:, Ex VO/VC=50.5bbdc/-17.5atdc(-=btdc)

1989GTATransAm

iTrader: (3)

PipeMax does calculate overall exhaust system lengths. However again that is if you do not use an exhaust termination box. Think about what the term "exhaust termination box" means.

Mystyk_Wynds

Well then there is some significant information being left out. All the links below quantify that the secondary length is as important as the primary length diameter. Now under no circumstance am I saying that you don't know what your talking about.
I just see it in a logical sense. If there is a tunable secondary length then it would mean a straight pipe off the collector, not the entire exhaust system, if this being the case, then putting pressure wave box at that point, would act as an end to the pipe, so you can put a cat and exhaust without it affecting the tune.
Now most of these links indicate that, also most say that on a street car the most important two aspects of the exhaust is the primary pipe diameter and secondary length. It seems that once you put a pipe on the collector this seems to semi negate the primary length and collector length.
I have also noticed that primary diameter affects the rpm at which torque peak occurs and primary/secondary length affects the under/over torque curve, secondary have the greatest effect in these areas. The collector effects the effeciency/strength of the scavenging. Or so that what I've managed to pull out of the reading, correct me if I'm wrong, I want to know this as best I can.

http://www.lextreme.com/forums/showthread.php?t=10419

http://www.popularhotrodding.com/tec...s/viewall.html

http://www.fordmuscleforums.com/all-...culations.html

http://www.3geez.com/forum/showthread.php?t=6466

http://www.popularhotrodding.com/eng...re/0505em_exh/

http://www.billzilla.org/engexhaust.htm

http://www.3geez.com/forum/showthread.php?t=6466

http://www.superchevy.com/technical/...h/viewall.html

http://ls1tech.com/forums/advanced-e...se-tuning.html

http://www.j-body.org/forums/read.ph...40299&t=439986

http://www.team-integra.net/forum/bl...ine-power.html

http://www.sandersonheaders.com/Lets-Get-Technical.html

http://www.castheads.com/2into1_systems.php

http://www.stangtv.com/tech-stories/...n-performance/

1989GTATransAm

iTrader: (3)

I guess the terminology is the difference here. When using an exhaust termination box(ETB) I think of the secondary length as that part past the ETB until the exhaust exits out of the tail pipe. To me the part where the primary pipes end at the collector and where the collector terminates into the ETB is the "collector length". On a race car the collector terminates and goes into the atmosphere. Usually this length is somewhere around 14" to 18" for the highest harmonic effect depending on the build of the motor.


If there is no ETB or atmosphere as in the case of the race car than the secondary length would be from where the primary pipes end at the header and the exhaust exits out the tail pipe. This would include the mufflers and can be quite long as you have stated. So I consider the collector length and the secondary length as two different things depending on the application. I hope this clarifies where I am coming from.

Mystyk_Wynds

I agree with the terminology being different, I should have suspected as I had a hard time determining what was the collector and what was the secondary. I mean they usually are bolted or welded together.

Yes your view of a secondary is anything after the PWB. To me and what I have read, is the secondary is the length of pipe after the collector, before the PWB. I think the confusion comes from different sections of an exhaust system, being referred by different ppl,companies, etc, by different terms.

Honestly I think we should or you, start a thread of exhaust terminology, at least to prevent other from being confused. not all cars have the same number of components, Hell we should give great diagrams too. lol

So what does pipe max or the program you have say my secondary or all of the exhaust situations should be? I've got 4 different lengths from 4 different programs range 36-56".

something like how these show harmonics and lengths?:
http://www.lextreme.com/forums/showthread.php?t=10419

http://ls1tech.com/forums/advanced-e...se-tuning.html

http://www.fordmuscleforums.com/all-...culations.html

If anything it helps me get things right, before I make a $400 mistake. However according to a online calculator, My engine is suppose to make peak torque @ 4050 rpm??? Does that sound right?
If so, could I get those calculations for 4k, 4.5k, 5k? an Your recommendations as this bieng 95% street car, where I should tune it?

1989GTATransAm

iTrader: (3)

You could be making peak torque at 4050rpm. Maybe you should purchase Larry Meaux's PipeMax program and plug in your numbers.

For my motor here are the total exhaust lengths. These are without an exhaust termination box.

8.1, 16.2, 32.3, 64.7 and 129.4