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Discussion Starter #1
Question for the street car drag racers...

Looking to put mufflers on my street car but need every bit of ET at the track until I build a bigger bullet. Thinking about getting the Borla XR1's but can't decide if it makes sense to go with the 3inch straight thru or the 3.5inch straight thru? Any advantage of going bigger? Plan to just add a short extension to the collector and hang the mufflers about right under my seat. No, H, X or Y pipe.


The plan is to go with a 540ci or bigger on the next motor.
 

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I have a 10.0 bbc bracket car. Tried 3" and 3.5" exhaust and had no difference in performance. Go with the 3", it fits so much nicer.


jmo....



bob
 

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Go with the 3.5 and just order the 598 and be done with it. You might as well spend the money so I can watch. Everyone knows I'm spending your inheritance so the quicker I'm broke the sooner you get the car. LOL> Dad.
 

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Discussion Starter #6
Go with the 3.5 and just order the 598 and be done with it. You might as well spend the money so I can watch. Everyone knows I'm spending your inheritance so the quicker I'm broke the sooner you get the car. LOL> Dad.
Well, Trans and Cage would have to come before the 598 so I figure I will just make it quiet for now so that when I pull into the water and make a bunch of noise with the the open exhaust followed by a slow pass everyone in the stands won't be disappointed.

Keep spending, I'll be pretty upset if we all have to argue over money when your gone.

Anyway, with the baby on the way I have to think Economically and Shafiroff even put it in the name. If the wife can say it was a deal then I guess I can try that one too....:):):) It could be a "street engine".

http://www.shafiroff.com/econo/582_econo.asp

I was really hoping someone would say the XR's are over priced and they had similar performance with MagnaFlows or something else. I have read a lot on here and it looks like the Flowmasters are going to slow me down. The Borla's are the consistent " I didn't loose any ET" mufflers from what I can find.
 

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Absolutely you can go with the dynatechs. They are much cheaper BUT they are aluminized, not stainless. Just so you know. With an exhaust as short as yours, the loss from one to the other will be minimal. The 3" will help you sustain low end/mid range numbers. You may sacrifice a small amount of top end but the alternative of the 3 1/2 losing bottom end and gaining top end is probably going to slow you down a bit. What header size are you using? Are you going to change header size when you get the new motor. New headers will mean a redo of the exhaust anyway, because no two headers are built the same, so you 'll have to reshape it regardless. These are all things you need to decide for yourself. If your changing headers, your changing exhaust, so go with the smaller system on the smaller motor and sell everything to finance the new headers/exhaust. My $0.02
 

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So if an engine make 750hp N/A what would one recommend for pipe size with just mufflers & turndowns ???????????????
 

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So if an engine make 750hp N/A what would one recommend for pipe size with just mufflers & turndowns ???????????????
Whats the specs on the engine? Lower RPM motor......3 1/2. Higher RPM motor........4" X pipe if you desire....but not one of those cheap ass ones that just smash the two exhaust streams into each other at 90* angles.
 

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Whats the specs on the engine? Lower RPM motor......3 1/2. Higher RPM motor........4" X pipe if you desire....but not one of those cheap ass ones that just smash the two exhaust streams into each other at 90* angles.
consistantly 5300 to 6400 rpm 535 cu.in.
 

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consistantly 5300 to 6400 rpm 535 cu.in.
3 1/2". Actually at that low an RPM you can even make a strong case for 3". Its obviously a torque based motor so the smaller size will really work well with your combo.
 

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Discussion Starter #13
Absolutely you can go with the dynatechs. They are much cheaper BUT they are aluminized, not stainless. Just so you know. With an exhaust as short as yours, the loss from one to the other will be minimal. The 3" will help you sustain low end/mid range numbers. You may sacrifice a small amount of top end but the alternative of the 3 1/2 losing bottom end and gaining top end is probably going to slow you down a bit. What header size are you using? Are you going to change header size when you get the new motor. New headers will mean a redo of the exhaust anyway, because no two headers are built the same, so you 'll have to reshape it regardless. These are all things you need to decide for yourself. If your changing headers, your changing exhaust, so go with the smaller system on the smaller motor and sell everything to finance the new headers/exhaust. My $0.02

I currently have a set of Hedman Hedders that are 2inch primary tube to a 3inch collector. I had a set of 2.5inch Borla's on it but I had 2.5inch pipe all the way back to the rearend with an H pipe. When I took it off the car picked up 3 tenths. The car doesn't see more than 6000rpm (Hydraulic Cam) and it makes 450hp at best. I see your point, my cheap street headers will most likely have to go. Just wanted to quiet it down incase I want to take it to the store without loosing any performance. Since I don't need have a high rev BB maybe it will pick up with the 3inch. Or maybe I'll try the 2.5inch right off the header. Any thoughts on that route?

I really appreciate the help. I planned to put the exhaust together without welding it so I could easily remove it if needed or to put on the other motor. Just my thoughts, but like I said. I see your point.

Thanks again..
 

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I currently have a set of Hedman Hedders that are 2inch primary tube to a 3inch collector. I had a set of 2.5inch Borla's on it but I had 2.5inch pipe all the way back to the rearend with an H pipe. When I took it off the car picked up 3 tenths. The car doesn't see more than 6000rpm (Hydraulic Cam) and it makes 450hp at best. I see your point, my cheap street headers will most likely have to go. Just wanted to quiet it down incase I want to take it to the store without loosing any performance. Since I don't need have a high rev BB maybe it will pick up with the 3inch. Or maybe I'll try the 2.5inch right off the header. Any thoughts on that route?

I really appreciate the help. I planned to put the exhaust together without welding it so I could easily remove it if needed or to put on the other motor. Just my thoughts, but like I said. I see your point.

Thanks again..
Get rid of the headers! Way to big a primary for 450 hp. You could easily get away with 1 5/8 or MAX 1 3/4. Go with a smaller primary on the header, 3" to the muffler and 2 1/2" out to the back and you'll have a nice system. Flowmaster mufflers perform the worst of all the major brands.....just some info there......but they sound the best IMO. You could even stick with the 2 1/2" front pipes if you wanted until the bigger motor comes....then 3". The front pipes will need to be redone as they will not match up with the new headers. The smaller primaries on the headers ( I would go 1 5/8 ) will make it feel like a completely different car!
 

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Get rid of the headers! Way to big a primary for 450 hp. You could easily get away with 1 5/8 or MAX 1 3/4. Go with a smaller primary on the header, 3" to the muffler and 2 1/2" out to the back and you'll have a nice system. Flowmaster mufflers perform the worst of all the major brands.....just some info there......but they sound the best IMO. You could even stick with the 2 1/2" front pipes if you wanted until the bigger motor comes....then 3". The front pipes will need to be redone as they will not match up with the new headers. The smaller primaries on the headers ( I would go 1 5/8 ) will make it feel like a completely different car!
Don't listen to Mufflerguy... Keep those headers.

Just buy a bigger bullet to fit the headers. :p

Think towards your future. If you are going to get a new motor soon you may want to buy parts that will work on your current motor but best be suited for the new one. That way when you get the new motor you already have parts for it.
 

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Don't listen to Mufflerguy... Keep those headers.

Just buy a bigger bullet to fit the headers. :p

Think towards your future. If you are going to get a new motor soon you may want to buy parts that will work on your current motor but best be suited for the new one. That way when you get the new motor you already have parts for it.
You know what......lets back up the bus a minute.........what size motor is in the car now? I'm under the impression this is a small block car w/ a 2" header...........is it a BBC now? If so.....leave the headers, 3" front pipes to 2 1/2" tailpipes. You will be changing the headers with the 598 to something around 2 1/8 or 2 1/4. The 540 is going to need a minimum of 3 1/2" exhaust BUT it will not line up with the bigger headers when you switch motors, so anything you really do now will be lost when the motor swap happens. What mufflers are currently on the car? You may want to just change the mufflers for now and deal with the piping issues when the motors get swapped. Sorry if I gave you bad info.........I was under the impression it was a small block car. :(
 

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Discussion Starter #17
Thanks mufflerguy,

I thought they were smaller but I looked them up before I posted earlier and they are 2inch. They were cheap from Summit 9 years ago when I built the car right out of school and bigger was always better back in the day I thought. Actually the guys at Hedmen suggested them if I remember correctly. Anyway, now I have more to think about... Time to find someone with a smaller set of headers that I can try I think...

Josh, The motor debate is to go tall deck or not. If I am going big, well then I might as well go really big... Another set of headers...
 

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You know what......lets back up the bus a minute.........what size motor is in the car now? I'm under the impression this is a small block car w/ a 2" header...........is it a BBC now? If so.....leave the headers, 3" front pipes to 2 1/2" tailpipes. You will be changing the headers with the 598 to something around 2 1/8 or 2 1/4. The 540 is going to need a minimum of 3 1/2" exhaust BUT it will not line up with the bigger headers when you switch motors, so anything you really do now will be lost when the motor swap happens. What mufflers are currently on the car? You may want to just change the mufflers for now and deal with the piping issues when the motors get swapped. Sorry if I gave you bad info.........I was under the impression it was a small block car. :(

Its a BBC, 454. It had 2.5inch exhaust tube and mufflers (Borla SS Universal XR1 taken off a dually with a 454, hand me downs from my uncle) The car would run the best of 12.20 through the exhaust. I try to run O/C at Milan on the heads up races so I can watch some fast cars when I am back on the trailer... :) So, I have to run 12.0 or quicker for this class on friday night heads up. I pulled the exhaust and went 11.99 so I am the guy everyone has to chase down and really can't break out. But I hate the car being so loud and then running a 12sec pass. Yes, it should run faster but I put it together to drive around all day on the street, now instead of spending time and money on heads, cam, intake, ect. I would most likely just get a complete big inch motor. Maybe the end of this year.

So, maybe I just put a short run of 3inch straight pipe to the 2.5inch mufflers that I have and see what it does. I just thought if the muffler was large it would be similar to open headers.

No worries about thinking it was a sbc.. I see that you help quite a few guys on here so I don't know how I would keep it straight.:):):):)

Thanks again.
 

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If its built to be a street car then I wouldn't be concerned about what it does at the track. It is what it is. When you go with the max effort motor, then build something suited to the track. If you take those borlas and just stick a short piece of 3" pipe off the headers, then open the muffler inlets to 3", you'll pick up some et, but the car will SUCK to drive around sounding like that. What does the car MPH like at 11.99?
 

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If its built to be a street car then I wouldn't be concerned about what it does at the track. It is what it is. When you go with the max effort motor, then build something suited to the track. If you take those borlas and just stick a short piece of 3" pipe off the headers, then open the muffler inlets to 3", you'll pick up some et, but the car will SUCK to drive around sounding like that. What does the car MPH like at 11.99?
109mph.. TH400, 4.11 gear, 3680lbs with me in it. (I could stand to loose a few pounds) Started as a street car, end up having more fun with it at the track with my father but don't have $15K for the new motor at the moment.
 
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