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DJ, check out Part Deux of my vendor survey re headers...:D
 

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Drive a Z06 with long tube headers and you will not care what anyone says, the car really comes to life with long tube headers. :)
 

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hcvone said:
Drive a Z06 with long tube headers and you will not care what anyone says, the car really comes to life with long tube headers. :)
Preach on, brother.. Preach on.

I totally agree, here. You may need to just drive a car with the headers.

I think it's important to decide what you're after. As we all know, you could have a 800 HP car that can't plant the power on the pavement, and the car won't run as quickly as a lower HP car with a different set-up. But if you want to be able to say you have the most HP/torque/whatever -- on paper -- then that's one approach. If you don't care so much about the NUMBERS, but feeling the change, and having the mod make sense with other mods is important, then that's another approach. It's probably "easier" to talk dyno numbers here, since most of us can't/don't meet up with others with similar mods and compare increases by actually running against one another.

I may never get my car on a dyno (well, if Carl can help it/me, that won't be true), but I "know" that the car is much quicker now, and that opening up the exhaust when increasing flow ahead of the intake is ALWAYS a good, fundamentally-sound power-making measure.

-Kirk
 

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and that opening up the exhaust when increasing flow ahead of the intake is ALWAYS a good, fundamentally-sound power-making measure.
I wouldn't dispute that your car is now faster..

But, I do take exception to that ALWAYS. Back in the old days, I would generally agree with you. Exhaust manifolds, in particular, tended to be very restrictive.

But with an engine like the LS6, the great numbers are made by *tuning*. That's how an engine can have a volumetric efficiency over 90% or 100%. That means that it takes in more air than it actually displaces. This is the "supercharging" that results from the careful sizing and matching of the components.

Making the 'tuning' work over a wider rpm range is the reason you see intakes with dual runners (one active at lower rpms and the other, or both, active at higher rpms). That is now common on many car, minivans, etc.

Just 'opening up' can negatively impact that tuning.

It's easy to think that bigger is better for horsepower when it comes to exhaust, but that often isn't the case with highly tuned engines. A simple thing like going from headers with 1 3/4" primaries to 1 7/8" primaries can reduce *peak* power.

There are reflected pressure waves in any exhaust system. When that exhaust valve cracks open, a pulse of air at extremely high velocity travels down the primary. When it expands at the collector, it reflects back up all of the primaries connected to that collector.

Those other primaries will see periods of both positive and negative pressure. Ideally, the next cylinder to fire will see a negative pressure - a vacuum - at the exhaust valve when it is opened.

You can time the pulses to make that happen for some RPMs, but not all. Any change to the exhaust configuration will impact the timing of these waves. Engine designers go to great lengths to optimize all of this. That is why I keep harping on it ;)

Similarly, where you locate the exhaust crossover (aka balance tube) - whether 6" behind the headers or 36" - can impact tuning in ways that are not intuitive.

I think the crossover location is a great example. Most of us have no 'gut' feeling for what moving the tube should do. Having had the extended opportunity to play with one of the best engine simulators ever developed, I spent hundreds of hours over a few years investigating these questions on my own time. The basic answer is usually "it depends".

I hope to get a model of the LS6 built and offer more specific info on what should work for that engine in different combinations.
 

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Well, I hear both sides and personally I tend to stand closer to BrianK's side of the road. Why, well because I have done so much foolish stuff in the past. There, I've said it, I have been very foolish with some of my previous mod escapades. Now older, and maybe a tad wiser, I am a little slower to jump into mods.

I have done so many things to my cars (toys) in the past which not only made them slower, but more unreliable and less fun to drive. I read all the hype, all the advertising and bought into it without thinking it through, doing a little homework. Reminds me of the old movie starring Jimmy Stewart "How the West Was Won". Jimmy plays a mountain man and in one series of scenes he gets lured into a cave by a pretty woman offering booze. Of course, once in the cave, they rob him and throw him in to a pit. He miraculaously survives and gets payback. But as he later explains to a very young marriage minded Debbie Reynolds - I'm not the guy for you because I will always be lured into the cave.

Well, for a long time, I was always lured into the cave - but not anymore. So, yes I take an inordinate amount of time sometimes to check the claims out, think about things, compare notes, strive to find the truth hidden in a veritable ocean of hype. There are some really good vendors/tuners and parts out there, ya just gotta find them. Actually, I find this to be kinda a fun challenge - I mean afterall, we are talkin' TOYS here.

You would not BELIEVE some of the things various vendors have told me while soliciting info re headers. One of the lesser known ones told me that the '02 Z06 heads are completely different than the '01 heads and they have gone back to circular exhaust ports. BTW, that vendor is not one of the ones I reported on. :eek:

I will be shortly posting part three of my headers/vendors survey. It is just possible - MAYBE - I have some very interesting news. Stay tuned. Right now, I have another damn meeting to go to! :( :( :( :( :( :( :(
 

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BBYU- since you have been conservative re mods per your post, what's your experience with the air intake mod?
Did it make a difference and were you able to objectively see that? I'm considering a Hall Tech SideWinder now for my '02.
 

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LaVette (Janet?) I put some of my thoughts on this subject in response to a thread called "More Rookie Questions ..Advice" in the New Products section. My car with only 1,100 miles on it, 198 degrees water temp (a bit on the warm side) and only the Vortex dynoed out at 420.5 crank h/p and 412 ft/lbs of torque - this on a particular dynojet that I have tested other cars on previously, and seems to be more "conservative" than other units I have tested on. GM sez I have 405 and 400, so yes I am happy. People whose opinion I trust have told me that i need at least a few more thousand miles before engine will make full power - also, I was clearly getting some detonation and KR pull back at around 6100-6200 rpms.

I wanted a cold air system and based upon my own opinions and research, the Vortex or ProFlo (same basic thing) was as far as I personally wanted to go in that direction. Also, if you want to read a mag test on it, check out Jan 2000 issue of Corvette fever..

Once again, this is a very controversial subject and this is just my opinion. I sent Frank Calmes my hardcopy Dyno sheet data last week-end and hope to have it posted shortly... Take care and enjoy your EB! :D
 

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I'm with you Carl, let these guys talk. My car is significantly stronger with the headers from idle to redline.
I don't think anyone is debating that. The question is whether it could be stronger with something more specific to the stock LS6. And an LS6 with a mild cam may want something else..

Failing hard numbers and some evidence of R&D, vendors are just throwing parts at the problem. Clearly, that can work but rarely is it optimal.
 

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Hey BrianK,

If I were an automotive engineer, then I'd probably be able to say that you were right or wrong with respect to your response to my post here. But since I'm not, then I shan't. :) What I WILL say is a clarification of my comment about making power: When increasing the amount/flow of air into the intake, it is a good MEASURE for making power. That is, fundamentally, it makes sense, and (ok, "almost always") makes power. I did NOT say that it makes power across the entire RPM range, nor that it might not hurt torque. Furthermore, I didn't say anything about increasing the diameter of any component of the exhaust. Rather, by opening the exhaust, along with increasing pipe diameter in some cases, I mean that you can make power gains even by having mandrel-bent exhaust piping rather than crimped piping, for example. Certainly making the exhaust LARGER in diameter everywhere is NOT a recipe for more power. Even I know that. ;)

Again, it's important for anyone here to determine what he wants from the car before modding it. And, since we all don't want the same thing, then rarely are we going to agree on a single product as being appropriate for all of our individual set-ups.

Also, it's equally important to realize that despite millions (or whatever) spent on R&D by the automakers to put out a highly-tuned product, these automakers have to watch costs and appease certain demographics. Some people don't care about costs, and some people want more than the car offers from the factory (but bought the car anyway). I'm convinced, since my car is performing better now than it did with all of the factory equipment on it, that the car was simply not tuned optimally from the factory.

Trust me, when I heard that an intake and LONG-TUBE HEADERS were the first must-do mods upon my introduction to Corvette modding, I thought "Huh?! But they were like the LAST thing to do to my '93 Mustang Cobra..." So, I was skeptical from the git-go on this. Hwever, I've got the TPIS's on my car now, and the car is just beastly...

...Just don't ask me to quantify "beastly," 'cause I can't. :)

-Kirk
 

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Kirk, I agree with you 110% that all automakers compromise to meet a variety of sometimes conflicting goals such as cost, emissions, performance, safety, God knows whatever other Fed laws, etc. During the course of my recent header survey, the TPIS system was the one most often cited as "the setup" by individuals as well as tuners/vendors.

I still do not personally like mild steel on an exhaust, but TPIS is certainly at least my "plan B" based on what I have found to-date. TPIS, TTS, DRM units have been around for a while, that is why I am very interested in following up with Chuck Mallet, re his recently designed "D" port headers which include a stepped collector. I will be talking to him again and either getting test info from him and/or his customers - and of course will make this info available to all. If they are not what they say they are, I am hoping to get Carl's guy to take a set of TPIS and port match tem for me as he is for Carl. I will not have a heads and cam car, but i do think this extra step may be worth it. Maybe after "baby dumpling" who starts college next year, gets to her junior year I will either think about more mods or start planning for the '06 Z06!! :)
 

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BLEUBYU said:
If they are not what they say they are, I am hoping to get Carl's guy to take a set of TPIS and port match tem for me as he is for Carl.
Hey Blue,

FYI, "Carl's guy" installed my headers, too -- he IS good, so by all means, if you're looking to take your car somewhere where they really know their stuff, Dale (at Berrell Auto) is the man. He just does great work, and he won't feed you any BS, either. (That's always refreshing to me.)

I'm just now seeing that you're from Manassas, VA. Have you ever been to OG Racing in Manassas? Nice guys there, and good prices on harnesses!

Oh, and despite already having the TPIS headers on my car, I'm very interested to hear what the tuners have to say about the different headers. I was surprised to see, for instance, that the Mallett cars (at Carlisle) all used Blackwings instead of a rammer-type set-up. We all seem so inclined to jump on the latest-greatest mod when in fact something more simple may be the best way to go.

Keep us posted!

-Kirk
 

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Kirk, been to OG, bought from OG - when I still had my modified '93 ZR-1. Porsche guy there said then that my ZR-1 was one Corvette he totally respected. Wait till he sees my EB Z06!!!!!

As for tuners using the Blackwing - yes, many of them do. Hmmm, could be another investigative project!

:lol:
 
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