1 5/8 or 1 3/4 ARH?

[Termilvr]

Should i go with 15/8 with a 2.5 inch collector or will it be more worth it to go with 1 /34 with 3 inch colector? Setup would be a whipple 2.9 on stock motor setup for 93. most of its use will be on the street.

 

[greengt88]

i would say 1 5/8......i think diameter should be based on what the car is making N/A. some may argue that it needs more exhaust flow capability. but i stick to my guns on this subject, this is also a very small bore small cube engine. i would expect you'd see better low end #'s with the smaller ones. if its a track car then id say go bigger, but not for a street car. Have you thought about using stepped headers? and for the $ i think Kooks is a better design.

 

[mach1033]

I had MAC 15/8 long tubes with the 2.9 whipple and it worked fine. you will really only need to get bigger if you were getting a head port with cams to take advantage of larger diameter primaries.

 

[bbk03gt24]

I had MAC 15/8 long tubes with the 2.9 whipple and it worked fine. you will really only need to get bigger if you were getting a head port with cams to take advantage of larger diameter primaries.

not meaning to hijack the thread from the OP, but how much of a HP or lbs. tq loss would you end up with if you went with the 1 3/4" LTs with the 3" catted x pipe on a cobra only putting down 475-500 rwhp b4 the switch to the 1 3/4" & 3" x? would it even be all that significant of a difference?

 

[04torchred]

Get the 1-3/4 x 3 setup. That blower puts a lot of air into the motor and you want to get it out.

 

[mach1033]

not meaning to hijack the thread from the OP, but how much of a HP or lbs. tq loss would you end up with if you went with the 1 3/4" LTs with the 3" catted x pipe on a cobra only putting down 475-500 rwhp b4 the switch to the 1 3/4" & 3" x? would it even be all that significant of a difference?

Before I blew my motor my set up was MAC long tubes into a 2.5 inch system. I was making well over 600 horsepower and 20lbs more of boost. My advice would be install a 2.5 system. I sold my system real quick when I put it the market section should you need to upgrade later on.

 

[98 Saleen Cobra]

1-3/4'' primaries definatley. It doesn't matter how much HP it's making N/A to determine the size of the exhaust.. Your car is taking in air and moving it out that's all it does. The more air you shove in the more air it needs to take out. Effiency is key. On 93 octane you are pushing probably 18psi and a lot of CFM into the motor it needs to get out just as quickly.. There is a reason why the new 5.0's exhaust choice is typically 1-3/4'' or larger.. Last but not least this topic is covered almost bi-weekly.. Do a search and you will see a lot of responses.

 

[GodStang]

1-3/4". 2.5" is a restriction at 600rwhp. You will be a bit past this. Why in the hell would you put a known restriction on your car. The n/a 300-400 rwhp fox bodies run 1-3/4". Why would you put smaller on a 600+ rwhp car. The 2.9l will put you in the are were you start thinking about 1-7/8".

 

[Termilvr]

Before I blew my motor my set up was MAC long tubes into a 2.5 inch system. I was making well over 600 horsepower and 20lbs more of boost. My advice would be install a 2.5 system. I sold my system real quick when I put it the market section should you need to upgrade later on.

did you blow your motor with the 2.9?details?

 

[mach1033]

did you blow your motor with the 2.9?details?

Yes I did. I dont want to hijack the OP's thread but I started a thread about it back in April when it happened. Just blew my motor with the 2.9 is the thread heading.