Does your exhaust choke your engine?

[LGAFF]

I guess, check out the difference in top speed on a 415

This 1995 ‪#‎Corvette‬ (https://www.facebook.com/hashtag/corvette?source=feed_text) ZR-1 415 CID LT5 was featured in the August 1998 Issue of Road & Track, that was John Lingenfelter’s yellow 1995 ZR-1 for the top speed shootout. Mario Andretti drove all of the cars at the Fort Stockton test track and Lingenfelter's yellow ZR-1 ran 201.5 MPH with full exhaust and 218.1 MPH on open headers. This 415 CID LT5 produced 686 HP and is normally aspirated. The 1995 Corvette ZR1 415 CID is owned by Norm Koerner

[We Gone]

Funny you should bring this up. When Marc dynoed my 91 this week as it was cold out the first run he had an exhaust tube on to run the gases outside even with negative pull on it. he said the numbers came lower than suspected by a fair amount, Next runs he opened the door much better results.

So in his words yes flow makes a difference.

[Blue Flame Restorations]

I'm suspecting my Turq "Z" is a non issue for restriction. :-D

I'll let you know for sure once my hearing comes back to normal.

[Paul Workman]

Always an interesting topic!

I'm at 432 rwhp (read my signature for details) but still have the Magnaflow muffs with the 2.5" restriction (abrupt...restriction), and stock TB. Marc suggested a minor improvement to my porting, back when he was doing a spot of welding on my IH. I made that correction. Now, I;m itchin' to see how close those three tweaks get me to 450 rwhp, w/o going to cams or electric water pump (cams = 20 - 25, water pump = 10, TB maybe 5, 3" Dynamax 17228s maybe 3-4 more, the "510" mod = X? Getting close!

There is just sooo much potential locked up in these LT5s. I mean it is getting common place to approach or exceed the same power level at the wheels with the LT5 as the contemporary Corvette motors are making at the flywheel, in spite of using stock cams and giving up 18 or so cubic inches displacement. Gotta wonder: What were they thinking???

[XfireZ51]

I guess, check out the difference in top speed on a 415

This 1995 ‪#‎Corvette‬ (https://www.facebook.com/hashtag/corvette?source=feed_text) ZR-1 415 CID LT5 was featured in the August 1998 Issue of Road & Track, that was John Lingenfelter’s yellow 1995 ZR-1 for the top speed shootout. Mario Andretti drove all of the cars at the Fort Stockton test track and Lingenfelter's yellow ZR-1 ran 201.5 MPH with full exhaust and 218.1 MPH on open headers. This 415 CID LT5 produced 686 HP and is normally aspirated. The 1995 Corvette ZR1 415 CID is owned by Norm Koerner

That's a huge difference.

[We Gone]

The reason I am going to Corsa no cats over flowmasters.
Marc said with the extra head work he did better flowing exhaust would make better use of it. Possible 20hp!! over cats and flowmasters.

[Kevin]

well I've got the stock system, so yes

[LGAFF]

Ok apparently lingenfelter got busted by the Road and Track police; they had L98 cats on the car so it looked to comply with the rules, they got caught with a bypass switch that went to open headers. So R&T made them run it with the L98 in use at WOT. Busted!


The following week they ran the same car with high flow cats and still hit the 218!

[FU]

The difference between a loser and a winner , can be the one that can tweek the rules better. Ask any true drag racer.

[XfireZ51]

The ultimate Tweaker was Smokey Yunick.

[Karl]

Also in that article they removed the outside rear view mirrors for some extra mph.

[Locobob]

Ok apparently lingenfelter got busted by the Road and Track police; they had L98 cats on the car so it looked to comply with the rules, they got caught with a bypass switch that went to open headers. So R&T made them run it with the L98 in use at WOT. Busted!


The following week they ran the same car with high flow cats and still hit the 218!

I could see how L98 cats would totally choke that exhaust... they were designed for a car with 250hp... um yeah not going to work so well.

[batchman]

I got the idea on this site for take-off z06 cats. Haven't found a set yet but they look like the right answer for me. I'll take the 1-2 hp hit to keep from stinking up the grid while warming the engine up.

Cheers,
- Jeff

[Hog]

I got the idea on this site for take-off z06 cats. Haven't found a set yet but they look like the right answer for me. I'll take the 1-2 hp hit to keep from stinking up the grid while warming the engine up.

Cheers,
- Jeff

Assuming LS7 cats, and yes catkes vehicles do stink.

[Bob Eyres]

catkes vehicles do stink.

Hey, I resent that.:mad: Actually I do feel a little guilty for having no cats, but the sniffer says it's relatively clean and (legal) once it's warmed up.

I only had a conversation with John Lingenfelter one time, at Beech Bend. I asked him whether any back pressure in the exhaust was beneficial. He said "no, anything you can do to opened it up and let it breathe is good for more power". He implied that the LT5 really responded to a free flowing exhaust system. I followed that advice, and increased the 1/4 mi. trap speed by more than 7mph, (110-to-117mph).

[Paul Workman]

Hey, I resent that.:mad: Actually I do feel a little guilty for having no cats, but the sniffer says it's relatively clean and (legal) once it's warmed up.

I only had a conversation with John Lingenfelter one time, at Beech Bend. I asked him whether any back pressure in the exhaust was beneficial. He said "no, anything you can do to opened it up and let it breathe is good for more power". He implied that the LT5 really responded to a free flowing exhaust system. I followed that advice, and increased the 1/4 mi. trap speed by more than 7mph, (110-to-117mph).

So... What do you have now?

I'll show you mine if you show me yours (exhaust, you perv!:p)

SW 3" throughout, except for MF mufflers. Those puppies choke down from 3" to about 2-1/2" before splitting into two 1-3/4 outlet tubes...

The Dynamax 17228s are what I want to install, along with the NPPs for next spring driving season.

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/StainlessWorks2001Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/StainlessWorks2001Large.jpg.html)

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/StainlessWorks2005Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/StainlessWorks2005Large.jpg.html)

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/StainlessWorks2006Large.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/StainlessWorks2006Large.jpg.html)

[Bob Eyres]

So... What do you have now?

Listed in the sig. An old style B&B system, no cats, Watson headers. Way loud, but I'm used to it.

[XfireZ51]

Listed in the sig. An old style B&B system, no cats, Watson headers. Way loud, but I'm used to it.

Bob,

By that you mean you're going deaf. ;)

[Karl]

Listed in the sig. An old style B&B system, no cats, Watson headers. Way loud, but I'm used to it.

How does the car smell without the catalytic converters?

[-=Jeff=-]

How does the car smell without the catalytic converters?

That is a matter of personal preference, I think. my 89 was not bad, but I have cats on my 90 Z

[Hog]

That is a matter of personal preference, I think. my 89 was not bad, but I have cats on my 90 Z
You can always use gasoline that smells very attractive, Eau de Octane is a very enticing fragrance.

My Uncle has a US code Ferrari Testarossa, when our Province used the California style dyno sniffer test. he would take his car to a "guy" who installed cats and ran it through the cycle, thus passing. This would get his sticker for 2 years. Then we went to the OBD2 port testing and just uses a "cheater pipe". Not sure if he is running the non-cat European ECM calibration or not.

Not sure if it's an actual emission that makes that offputting smell or not.


Carbon Dioxide-CO2
Part 1 of a 3 way catalyst
CO2 is odourless, tasteless and is a greenhouse gas, allowing solar radiation to hit the Earths surface where the radiation heats the surface of the Earth, the surface then heats the air causing convection currents. Higher CO2 concentrations prevents the escape of thermal energy from the planet.


Oxides of Nitrogen-NOx Part 2
Oxides of Nitrogen is a blanket for many compounds
Nitric oxide (http://en.wikipedia.org/wiki/Nitric_oxide), also known as nitrogen monoxide, (NO), nitrogen(II) oxide
Nitrogen dioxide (http://en.wikipedia.org/wiki/Nitrogen_dioxide) (NO2), nitrogen(IV) oxide
Nitrous oxide (http://en.wikipedia.org/wiki/Nitrous_oxide) (N2O), nitrogen(-I,III) oxide
Nitrosylazide (http://en.wikipedia.org/wiki/Nitrosylazide) (N4O), nitrogen(-I,0,I,II) oxide
Nitrate radical (NO3), nitrogen(VI) oxide
Dinitrogen trioxide (http://en.wikipedia.org/wiki/Dinitrogen_trioxide) (N2O3), nitrogen(II,IV) oxide
Dinitrogen tetroxide (http://en.wikipedia.org/wiki/Dinitrogen_tetroxide) (N2O4), nitrogen(IV) oxide
Dinitrogen pentoxide (http://en.wikipedia.org/wiki/Dinitrogen_pentoxide) (N2O5), nitrogen(V) oxide
Trinitramide (http://en.wikipedia.org/wiki/Trinitramide) (N(NO2)3), nitrogen(0,IV) oxide


Hydrocarbons
And the last part of a 3 way cat, the Hydrocarbons, perhaps its the burned or partially burned hydrocarbons that give off that smell.

I found this little ditty about Hydrocarbon emission classification(wiki)
Technology for one application (to meet a non-methane hydrocarbon standard) may not be suitable for use in an application that has to meet a total hydrocarbon standard. Methane is not directly toxic, but is more difficult to break down in a catalytic converter, so in effect a "non-methane hydrocarbon" regulation can be considered easier to meet. Since methane is a greenhouse gas (http://en.wikipedia.org/wiki/Greenhouse_gas), interest is rising in how to eliminate emissions of it.


I remember in about 91-94 the GM TBI(throttle body injection) engines used catalytic converters which caused a strong "rotten eggs" smell. That indicates some sort of Hydrogen Sulphide (H2S).

Did any of the ZR-1's suffer from any "rotten eggs" smells?

[Bob Eyres]

Am I deaf? Not yet. Like ancient Odysseus, I strap myself in and enjoy the siren song of the screaming LT5.:eek:

The wife hates the loud pipes. But I just tell her,"plug in your ear buds" and hang on :)

Does it smell bad? No really noxious fumes, but it does smell like a Twentieth Century Beast, like the drag strip, like "Victory" :cheers:

Seriously though, there is one downside. Because my car is white, it does, over time, leave a barely noticeable unsightly yellow stain over the entire rear end. Which takes a lot of rubbing to remove.

You know how we hate unsightly yellow stains on our rear ends. :p

[WARP TEN]

Am I deaf? Not yet. Like ancient Odysseus, I strap myself in and enjoy the siren song of the screaming LT5.:eek:

The wife hates the loud pipes. But I just tell her,"plug in your ear buds" and hang on :)

Does it smell bad? No really noxious fumes, but it does smell like a Twentieth Century Beast, like the drag strip, like "Victory" :cheers:

Seriously though, there is one downside. Because my car is white, it does, over time, leave a barely noticeable unsightly yellow stain over the entire rear end. Which takes a lot of rubbing to remove.

You know how we hate unsightly yellow stains on our rear ends. :p

I have been reading lately about a product called Rejex that a few have mentioned on this forum. You might try that after a good cleaning. It looks interesting on their website. Haven't used it yet but it might make future stains easier to remove. - Bob

[gbrtng]

I guess, check out the difference in top speed on a 415

This 1995 ‪#‎Corvette‬ (https://www.facebook.com/hashtag/corvette?source=feed_text) ZR-1 415 CID LT5 was featured in the August 1998 Issue of Road & Track, that was John Lingenfelter’s yellow 1995 ZR-1 for the top speed shootout. Mario Andretti drove all of the cars at the Fort Stockton test track and Lingenfelter's yellow ZR-1 ran 201.5 MPH with full exhaust and 218.1 MPH on open headers. This 415 CID LT5 produced 686 HP and is normally aspirated. The 1995 Corvette ZR1 415 CID is owned by Norm Koerner

I have it on good authority the engine is a different car now having passed thru SW and another owner.