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

[Viet Nam Vett]

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

Heh Thanks Joe,
Went to the site and also called Mike the owner. "Can We Talk" ( Joan Rivers)
Mike took some time to talk with me about his pipes and I learned a few things. He did recomend the 2.5" internal baffle system which has and Outside Diameter of 2 3/4 ".

He also has the pipe available with out the header pipe connection which does make it cheaper. This elimitates the need to lob off the front of the pipe when you fab to the header collector if you were to buy the complete pipe.

Anyone using sweet thunder.......??

 

[SG4206]

Nam Vet-
The test Tom told you about gives direction; the key he mentioned was that no additional tuning was performed. They left power on the table.
Less back pressure normally creates a stronger signal to the carb;which richens the mixture. The opposite is also true ; more back pressure tends to lean because of a weaker signal to the carb. You can now imagine how many combinations of intake,carb,cam,heads and exhaust will act differently on the same size engine. This has driven me crazy over last 15 years of engine dyno time. Going from open headers to closed quite exhaust like you want ; can cost as much 50-75 HP on 500 inch engines.
I have to advise you to use what you want , you have enough bottom end torque ,the difference in power one way or the other might be worth 3-5 %. The only way to satisfy your question would to go to a chassis dyno and test this on your combination.
This is my opinion for any help or understanding it might give you .

Doug

 

[Viet Nam Vett]

Nam Vet-
The test Tom told you about gives direction; the key he mentioned was that no additional tuning was performed. They left power on the table.
Less back pressure normally creates a stronger signal to the carb;which richens the mixture. The opposite is also true ; more back pressure tends to lean because of a weaker signal to the carb. You can now imagine how many combinations of intake,carb,cam,heads and exhaust will act differently on the same size engine. This has driven me crazy over last 15 years of engine dyno time. Going from open headers to closed quite exhaust like you want ; can cost as much 50-75 HP on 500 inch engines.
I have to advise you to use what you want , you have enough bottom end torque ,the difference in power one way or the other might be worth 3-5 %. The only way to satisfy your question would to go to a chassis dyno and test this on your combination.
This is my opinion for any help or understanding it might give you .

Doug

Heh Thanks Doug,
Well it sounds like you have some good experience with motors & Dyno's over 15 yeras. So I can appreciate your answer. If I understand you then ..Back Pressure is the HP killer here. Even in the 4000-5500 RPM Range..or are you speaking about the complete power curve?

If the diff betwen 1 7/8 and 2.5'' doesn't show much then it's not worth the changeover in that power band width.

 

[JohnZ]

Remember - for a normally-driven civilized street engine (as your plan describes), what matters is TORQUE, not tach-twisting peak horsepower you only see over 5000 rpm. You can't have both - I'd focus on low and mid-range torque as the priority to optimize for your usage, not searching for that last few horsepower.

 

[Viet Nam Vett]

Remember - for a normally-driven civilized street engine (as your plan describes), what matters is TORQUE, not tach-twisting peak horsepower you only see over 5000 rpm. You can't have both - I'd focus on low and mid-range torque as the priority to optimize for your usage, not searching for that last few horsepower.

Man....I thougt I was having trouble with my eyes there for a second...The print got smaller and smaller... But I realized that you must have pushed the wrong button..:L

Heh John..I'm glad you finally joined in on the side pipe flogging party here. For a moment there I thought you had enough talk on this warn out subject.

So John...what da think?? I'm not after the last HP just want to maintain the 502's torque @ that 4200 RPM range. Not after the high end rev's..just lung lunching to the spine torque..

Can I still maintain that with the stock side pipe 1 7/8" internal baffel?? Or would you suggest I move up to the 2.5" Internal Baffel.

Quote*
I'd focus on low and mid-range torque as the priority to optimize for your usage, not searching for that last few horsepower.
-------------------------------------------------------------------------

That's Excactly What I Want To Do..... Will it work with the stock Pipes??

Thanks John

 

[SG4206]

The smaller, less noisy exhaust will cost you over the entire power range,but more pronounced at upper rpm levels. I wouldn't worry about drivability , you have plenty of torque regardless.
The crate 502 is rated with open exhaust? So you will be down from their numbers no matter which exhaust you choose. The peak will remain very close to 4200 rpm , you'll just be down maybe 30- 70 ft. lbs. You are still looking at only 3-5 % between the your pipe sizes. You are correct , it's not worth the changeover. Do you see the picture I'm trying to paint?

 

[65TripleBlack]

Viet Vett:

Be careful about those 2 1/2" pipes. I also spoke to Mike Sweet Thunder a few months ago. The way our conversation went, I generally got the impression that the "GNM" pipes would make your ears bleed. If I were you, since you are going to the trouble of fitting headers to your ratmotor,then I would use the "high perf" 2 1/4" pipes as a compromise. Mike also told me that his standard 2" baffled pipes are slightly louder than stock GM, and the 2 1/4" baffled pipes are louder still.
I went through much research a few months ago, and could find NO testing that was valid. My car is a 327/365, with GM sidepipes already installed. The losses for the smallblock are, of course, less than for a big block, so I decided to leave mine as is.
There are some folks, I have been told, that have been able to fit the spiral turbos under stock covers. I would investigate that further. With the spirals, you will gain significant power, with less noise.

Joe

 

[Viet Nam Vett]

The smaller, less noisy exhaust will cost you over the entire power range,but more pronounced at upper rpm levels. I wouldn't worry about drivability , you have plenty of torque regardless.
The crate 502 is rated with open exhaust? So you will be down from their numbers no matter which exhaust you choose. The peak will remain very close to 4200 rpm , you'll just be down maybe 30- 70 ft. lbs. You are still looking at only 3-5 % between the your pipe sizes. You are correct , it's not worth the changeover. Do you see the picture I'm trying to paint?

Thanks SG4206,
Ahh...Soooo ...Motor Hopper...:L

That's the thing here..Bang for the Buck..I can always add the super duper pipes later if I'm not happy.. The only problem as stated before is I have to ruin a set of good used side pipes to fit to my headers Vs just buying the straight pipe from Sweet thunder.

Well...we can't keep beating a dead horse here..there's been plenty of info posted here so I guess it's up to me to deside.

Your point is valid and I know Richescorvette BB502 uses the same Sanderson Headers with the stock 2.5" down to 1 7/8 side pipes and he has told me he's happy as a Clam and that he's got boo-coo torque. Of corse his 502 is worked and not internally stock.

But thanks for taking the time to reply to my post..

 

[Viet Nam Vett]

Viet Vett:

Be careful about those 2 1/2" pipes. I also spoke to Mike Sweet Thunder a few months ago. The way our conversation went, I generally got the impression that the "GNM" pipes would make your ears bleed. If I were you, since you are going to the trouble of fitting headers to your ratmotor,then I would use the "high perf" 2 1/4" pipes as a compromise. Mike also told me that his standard 2" baffled pipes are slightly louder than stock GM, and the 2 1/4" baffled pipes are louder still.
I went through much research a few months ago, and could find NO testing that was valid. My car is a 327/365, with GM sidepipes already installed. The losses for the smallblock are, of course, less than for a big block, so I decided to leave mine as is.
There are some folks, I have been told, that have been able to fit the spiral turbos under stock covers. I would investigate that further. With the spirals, you will gain significant power, with less noise.

Joe

Thanks Joe,

I did look at the spirals...as well as the rest of the side pipe guys out their. Got lottsa info to sift thru..now it's up to me to make a selection. Thanks for taking the time to give me your input. The best info you can get is from people like your self who have had real world experience with the topic at hand..

Thanks again..

 

[Mikey1]

Simply add a cross pipe between those side pipes....that is kind of an X-pipe then.