Exhaust to y pipe doesn't match up???
 

Just bought and installed the Top Speed exhaust with a Motordyne y pipe and noticed that the collector on the y pipe to the single pipe on my top speed doesn't match up. The Top Speed single pipe is 70mm while the Motordyne is 3inch. It bolts up fine and sounds good but I don't like the fact that I have a 1/4 inch lip which means that the exhaust might not be flowing correctly. I checked out the Tanabe y pip and its OD is 70mm which matches perfectly to my Top Speed exhaust. Should I sell the Motordyne and buy the Tanabe or should I not worry about it??? Any help would be much appreciated.

2 things... TopSpeed FTL, I'd either complete the Motordyne CBE, or sell the whole thing and just buy a complete CBE

Why don't you like the Top Speed exhaust? It sounds great and fits perfect.

I wouldn't worry about it. I have it paired with my Tanabe exhaust. Any power difference would be minor.

I initially bought the Motordyne to take advantage of the high flow cat you can put in place of the staight pipe that I have know when I get ART pipes in the future. It might not make very much of a difference If I switched the y pipes but its bothering me that it doesn't match up how it should. I'm going to post it up for sale so if anybody is interested let me know. It's basically brand new. I'm willing to ship it and I have the original box it came in.

Are you using the straight pipe or cat currently? With the cat, it shouldn't make much diff at all, the restriction from the cells and when it necks back down, it's about 1/8th in all around. The XYZ outlet uses 3” OD tubing with a 0.062” thickness or 1.52mm.

My Tanabe pipe is 1.2mm thick or .047". That tells me the difference is .23622" or 6mm.

I have the straight pipe on right now. Haven't bought the cat yet. I also noticed with the Tanabe that its 60mm and 70mm. My Motordyne is 2.5inch with a 3inch out. Would that mean that the Motordyne flows better because of the bigger diameter pipping used. I read somewhere on another forum that the larger diameter y pipes cause you to lose a little torque down low. Is there any truth to this?

Yep, you lose a little but gain more area under the curve overall

I did notice a small torque loss after installing the Motordyne. Since the Tanabe has a smaller diameter would I possibly notice more torque down low?

You are really not missing much man, if anything at all. I gained 30whp with a full exhaust and LTH's. I gained hp everywhere, even down low. I would just stick with it. You have options with that Y pipe. The Tanabe is an awesome Y pipe, but it's also $500. $150 more for 1/4"... Think about it.

Idk....It would be nice to keep the Motordyne so I can match some ART pipes up with it. Also if its too loud with the ART pipes I can add the resonator or cat to the Motordyne and I can't do that with the Tanabe. Decisions decisions.....

I could also go with the Tanabe y pipe and get the Fast Intentions resonated high flow cats. Are high flow cats worth doing or should I go with the ART pipes? I would like to go with long tubes but I don't want to spend that much money.

I'd stop piecing things together...
Or if you really NEED that cat, get PPE headers, they cost a few hundred more than Art pipes, and no need to díck around here and there

If you go with a full CBE, I'm almost sure that Tony from Fast Intentions makes (kinda special order) a catted CBE.


Have you ever driven a car with no cats btw? It smells like death, I mean absolute death. You'll get cancer in about 5 min... So if that's something that doesn't suit you, you have your other option...
Get HFC's sell whatever you got, full catback, and I think this is the approach most of us take

If I was in TX, I'd let you borrow my resonated test pipes so you get a feel for them

Save money and just get the HFC on the Y pipe. It's 200 cell and 3". Very free flowing. You could then get ART pipes, or resonated test pipes for a lot cheaper than buying two HFC's.