Who Really Knows For Sure... Very Confusing?*%#

[Viet Nam Vett]

Who Really Knows For Sure... Very Confusing?*%#
I'm trying to determine which way to go when it comes to sidepipe size.
Since I have puechased a BB 502 I have to address the exhaust. There are several different schools on this subject and it starting to get me a little confused.

I will be doing steet driving and not exceeding 5500 RPM. I want all my torque in the upper midrage ...The 502 makes 567 LBS @ 4200 RPM.

I have already desided on the headers. In speaking with Rich Lagase he has suggested the Sanderson headers which are designed for the 502 BB and the midyear. They are designed to mate up perfectly with the exchaust port of the 502 and fit real nice under and around the motor leaving access to work in the engine compartment.

Rich uses this header on his beautifull 67 502 and it does fit and look great. Now here's the Rub... The stock 2.5 " side pipes flow down to 1 7/8 ' inside the tube which is restrictive.

School of thought #1 is ..If you are not running any more then 5500 RPM this isn't a problem. In fact..because of the smaller pipe the velocity of the gas is speeded up improving low end torque. The problem is after that 5500 RPM back pressure becomes an issue.

School of thought #2 is... The Allen's 2.5 inch "all the way Thru" Sipe Pipes will give you more HP and Torque thru the entire range. Draw back is that they are much louder. Or in other words a 2.5 inch pipe is better then the 1 7/8 pipe.

I wonder if ant one has done a shoot out between these to schools of thought. It would be nice to get some real data on this and not just rely on what the MFG tells you on his web Site.

I know that John Z has thoughts on the Factory 1 7/8 pipes in regards to not being very good as far as HP goes as well as SWC Duke.

Yes I know...This subject has come up before but it is still confusing.
Does any one have any real worl data here and or dyno comparison swithing between these two sizes? Or just some seat of the pants feel between the two.

Also I do understand that the Header pipe is also part of the equation..
but at this point I'm just trying to determine the best way to go as far as the side pipe.

What are your feelings and or opinion's on this topic. This would be a good subject for one of the Corvette mags. A side Pipe shoot out..

 

[BarryK]

Who Really Knows For Sure... Very Confusing?*%#
I'm trying to determine which way to go when it comes to sidepipe size.
Since I have puechased a BB 502 I have to address the exhaust. There are several different schools on this subject and it starting to get me a little confused.

I will be doing steet driving and not exceeding 5500 RPM. I want all my torque in the upper midrage ...The 502 makes 567 LBS @ 4200 RPM.

School of thought #1 is ..If you are not running any more then 5500 RPM this isn't a problem. In fact..because of the smaller pipe the velocity of the gas is speeded up improving low end torque. The problem is after that 5500 RPM back pressure becomes an issue.

School of thought #2 is... The Allen's 2.5 inch "all the way Thru" Sipe Pipes will give you more HP and Torque thru the entire range. Draw back is that they are much louder. Or in other words a 2.5 inch pipe is better then the 1 7/8 pipe.

Mark

excuse me if I'm missing something, but isn't the answer already in front of you?
You say the Sanderson Headers looks and fit great and although they drop down to a 1 7/8 size that isn't a factor until AFTER 5500rpm. You have already mentioned you are only doing street driving and not exceeding 5500rpm so any loss beyond this point shoudn't be a factor to you.

The Allen's 2.5" headers will allow you more hp beyond 5500rpm but again you say you will not be driving the motor that high to see the benefits anyway besides the added disadvantage of them being louder.

just my $.02

Barry

 

[ZRGator]

You might check to see if anyone has any knowledge of a product being sold called "The Baffler." As I was reading the ad, they seem to be a spiral insert for sidepipes that reduce the noise without affecting performance. If this is true, then you might go with the Allen set up just in case you ever "accidently" :eyerole get above 5500rpm.

 

[Viet Nam Vett]

Mark

excuse me if I'm missing something, but isn't the answer already in front of you?
You say the Sanderson Headers looks and fit great and although they drop down to a 1 7/8 size that isn't a factor until AFTER 5500rpm. You have already mentioned you are only doing street driving and not exceeding 5500rpm so any loss beyond this point shoudn't be a factor to you.

The Allen's 2.5" headers will allow you more hp beyond 5500rpm but again you say you will not be driving the motor that high to see the benefits anyway besides the added disadvantage of them being louder.

just my $.02

Barry

Maybe I didn't make my self clear.... Sorry... The side pipe inlet is 2.5" which tapers down to 1 7/8" internally.


The headers dump into a 3" collector and then with the included adapter drop to 2.5" to mate with the side pipe.

Kabish...???:L

 

[Viet Nam Vett]

You might check to see if anyone has any knowledge of a product being sold called "The Baffler." As I was reading the ad, they seem to be a spiral insert for sidepipes that reduce the noise without affecting performance. If this is true, then you might go with the Allen set up just in case you ever "accidently" :eyerole get above 5500rpm.

I have hrard of the baffle,,,I think there was some disscussion on this on the forum. I think that is yet another player in the side pipe wars..

 

[67HEAVEN]

C'mon Mark. Have a real close look at these numbers.

From cylinder heads to end tip of sidemounts:

(your Sanderson numbers)
Individual header pipes - 1 7/8" (averaging about 14" long) up to 3" collector down to 2.5" adapter down to 1 7/8" internal.

(my Hooker numbers)
Individual header pipes - 1 7/8" (each 50" long) up to 4" at collector to 4" side tubes.

Or sure, the Hookers are loud. Huh? What? Eh? :gap But, Mark, look at the numbers and ask yourself how these will compare in any category you wish to use: horsepower; torque; intimidation factor.

Have another look...

...before you lay your money down.

 

[skids]

Hey 67, them the ceramic coated? I have same exhaust except painted, I mean rusted headers. But new is on the way, hopefully by xmas. But what I really wanted to say was Hooker now has their sidemounts in stainless steel. Did you already know that and found out the price on these babys, or not. Just was wondering,cuz I don,t know price, but am gonna getum anyway cuz I wanna!!

 

[Viet Nam Vett]

C'mon Mark. Have a real close look at these numbers.

From cylinder heads to end tip of sidemounts:

(your Sanderson numbers)
Individual header pipes - 1 7/8" (averaging about 14" long) up to 3" collector down to 2.5" adapter down to 1 7/8" internal.

(my Hooker numbers)
Individual header pipes - 1 7/8" (each 50" long) up to 4" at collector to 4" side tubes.

Or sure, the Hookers are loud. Huh? What? Eh? :gap But, Mark, look at the numbers and ask yourself how these will compare in any category you wish to use: horsepower; torque; intimidation factor.

Have another look...

...before you lay your money down.

First off Man from the north country... Were in two different worlds here...You are after all out HP and into burning the legs of youg girls with those stove pipes you call side exhuast....Your motor has all the goodies inside with enough power to climb a tree straight up with the gear set up you have. From what I can see your into announcing your arrival with those side pipes to the people in the next province 30 miles from your domain.

The paint on your car requires an extra 60 HP just to compensate for weigh of the 80 some coats.

I..being a nice conservative guy who only wants to scare the people in church across the steet on Sunday do not require 4 inch flame throwers just to cruz around. I'm looking for that nice clean loud stock side pipe look.

So...I think were after 2 different things here. You ...WILD MAN...ME..COOL Man

 

[67HEAVEN]

Mmmm.....kay.

 

[67HEAVEN]

........burning the legs of youg girls with those stove pipes you call side exhuast....

By the way, if any young girls are seen in my car, it won't be them that's getting burned. (Mrs. 67HEAVEN)

 

[Viet Nam Vett]

By the way, if any young girls are seen in my car, it won't be them that's getting burned. (Mrs. 67HEAVEN)

 

[67HEAVEN]

Hey 67, them the ceramic coated?

Yes they are. They are almost 30 years old, but with very few miles on them. I had them ceramic coated this summer.

 

[ZRGator]

Intimidation factor...I love it. How do you chart that? Or is it a simple rule like: the rise in the sound of the pipes is directly proportional to the look of despair on the face of the Viper guy you are about to blow away?

 

[JL66REDCPE]

Mark - If the engine makes max torque at 4200 rpm then where does it make max horsepower ???? If it is at 5500 are below then wouldnt you be ok with the smaller sidepipes ?? Then the question becomes - how much faster will it make max horsepower with the larger pipes and is that of enough importance to you to go with the larger pipes. I think the key here is where the engine makes max horspower.

 

[Viet Nam Vett]

Mark - If the engine makes max torque at 4200 rpm then where does it make max horsepower ???? If it is at 5500 are below then wouldnt you be ok with the smaller sidepipes ?? Then the question becomes - how much faster will it make max horsepower with the larger pipes and is that of enough importance to you to go with the larger pipes. I think the key here is where the engine makes max horspower.

The Stock BB ZZ502 with Alum. Heads makes 502 HP at 5200 RPM....567lbs @4200 RPM........ Good point ..any body want to analyze This..?????

 

[65TripleBlack]

Who Really Knows For Sure... Very Confusing?*%#
I'm trying to determine which way to go when it comes to sidepipe size.
Since I have puechased a BB 502 I have to address the exhaust. There are several different schools on this subject and it starting to get me a little confused.

I will be doing steet driving and not exceeding 5500 RPM. I want all my torque in the upper midrage ...The 502 makes 567 LBS @ 4200 RPM.

I have already desided on the headers. In speaking with Rich Lagase he has suggested the Sanderson headers which are designed for the 502 BB and the midyear. They are designed to mate up perfectly with the exchaust port of the 502 and fit real nice under and around the motor leaving access to work in the engine compartment.

Rich uses this header on his beautifull 67 502 and it does fit and look great. Now here's the Rub... The stock 2.5 " side pipes flow down to 1 7/8 ' inside the tube which is restrictive.

School of thought #1 is ..If you are not running any more then 5500 RPM this isn't a problem. In fact..because of the smaller pipe the velocity of the gas is speeded up improving low end torque. The problem is after that 5500 RPM back pressure becomes an issue.

School of thought #2 is... The Allen's 2.5 inch "all the way Thru" Sipe Pipes will give you more HP and Torque thru the entire range. Draw back is that they are much louder. Or in other words a 2.5 inch pipe is better then the 1 7/8 pipe.

I wonder if ant one has done a shoot out between these to schools of thought. It would be nice to get some real data on this and not just rely on what the MFG tells you on his web Site.

I know that John Z has thoughts on the Factory 1 7/8 pipes in regards to not being very good as far as HP goes as well as SWC Duke.

Yes I know...This subject has come up before but it is still confusing.
Does any one have any real worl data here and or dyno comparison swithing between these two sizes? Or just some seat of the pants feel between the two.

Also I do understand that the Header pipe is also part of the equation..
but at this point I'm just trying to determine the best way to go as far as the side pipe.

What are your feelings and or opinion's on this topic. This would be a good subject for one of the Corvette mags. A side Pipe shoot out..

Try this website: www.spiralturbobaffles.com

I have been trying to find a good "apples to apples" dyno test, but have had no luck.

Joe

 

[Viet Nam Vett]

Try this website: www.spiralturbobaffles.com

I have been trying to find a good "apples to apples" dyno test, but have had no luck.

Joe

Thanks Joe,

My idea is to use the stock looking Corvette Side Pipe covers with the car. I don't want to go to those 3.5 to 4'' round large leg burners pipes. They do look cool if that's what your after ..but I like that stock look. I have been to this site before and it looks like they may have something there.

Like I said ..one of the vette mags should do a compairison on side pipes.

Thanks for the info...

 

[Tom Bryant]

If the Allens side pipes are like the originals only larger and fit inside the stock covers, they would be the only choice for performance with a stock look. There won't be that much of a difference in decibles. It would be like comparing loud to a little louder. The October issue of Hot Rod has a good header comparison done on their Chevy crate ZZ454 test engine. It has a couple mods like a 850 Holley and a mild hydraulic street cam.

They acheived the best averge numbers (518 hp) with 2" dia. primaries and 18" length 3.5" collectors. 557 peak torque@4100 rpm and 545 peak hp at 5400 rpm. 1 7/8" primaries and 18" collectors dropped peak hp to 516@5300 rpm but boosted peak torque to 560@3700 rpm. Average hp with the 1 7/8" was only down 1 at 517. Shorter collectors hurt the numbers across the board.

These tests were done without recalibrating the engine for each header and with open exhaust. The header adapers starting out big and reducing to 2 1/2 should effectivly lengthen the collector, though not as much as a full 3 1/2 tor 18 inches, but it will help. The killer will be necking that down to 1 78 inside the sidepipe chambered section.

I feel that the 1 7/8 headers are a very good choice but the stock 1 7/8 internal sidepipes will be power killers and not that much quieter than the 2 1/2s.

Nest month they will compare exhaust systems on this engine.

Tom

 

[65TripleBlack]

Okay, then check this out. Allen's has great rep, but these are cheaper, and offer more options.


www.sweet-thunder.com/

Bottom line:

There is no easy way to extract more power from a chambered system. The trade off is simple: increased noise is directly proportional to increased power. The use of the spirals provides better flow, with quiet operation. The reason for this is that it is not a chambered design. You will have to give up something to gain something.

Joe

 

[Viet Nam Vett]

If the Allens side pipes are like the originals only larger and fit inside the stock covers, they would be the only choice for performance with a stock look. There won't be that much of a difference in decibles. It would be like comparing loud to a little louder. The October issue of Hot Rod has a good header comparison done on their Chevy crate ZZ454 test engine. It has a couple mods like a 850 Holley and a mild hydraulic street cam.

They acheived the best averge numbers (518 hp) with 2" dia. primaries and 18" length 3.5" collectors. 557 peak torque@4100 rpm and 545 peak hp at 5400 rpm. 1 7/8" primaries and 18" collectors dropped peak hp to 516@5300 rpm but boosted peak torque to 560@3700 rpm. Average hp with the 1 7/8" was only down 1 at 517. Shorter collectors hurt the numbers across the board.

These tests were done without recalibrating the engine for each header and with open exhaust. The header adapers starting out big and reducing to 2 1/2 should effectivly lengthen the collector, though not as much as a full 3 1/2 tor 18 inches, but it will help. The killer will be necking that down to 1 78 inside the sidepipe chambered section.

I feel that the 1 7/8 headers are a very good choice but the stock 1 7/8 internal sidepipes will be power killers and not that much quieter than the 2 1/2s.

Nest month they will compare exhaust systems on this engine.

Tom

Thanks Tom,
Some good info there. I'll pick up a copy and take a peek