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.

And like DE said, it's much more difficult to piece things together. I was lucky that my exhaust worked and didn't sound like @ss. I was trying to measure parts I didn't physically have to make sure everything fit. Not only that, I paid $1750. If I could do it again, I would have gone with either a Motordyne CBE with HFC or F.I. and HFC's option. Same price, maybe a bit more, and I wouldn't have had to put in all the extra work.

I guess I could start over and buy another exhaust but the only one that is in my price range that is good from what I hear is the Invidia Gemini. What are y'all's thoughts on the invidia? Really appreciate the input guys!

throw up a clip of your current exhaust. Looking at mine, you would think it came from the same manufacturer.

http://www.the370z.com/members/ss_fi...band-clamp.jpg

http://www.the370z.com/members/ss_fi...h-flow-cat.jpg

http://www.the370z.com/members/ss_fi...77-midpipe.jpg

How do you upload videos on here???

Mine came from this site on my page. If you have them on photobucket or something, click the image link under the "go advanced" tab. Paste the URL of the picture in the popup box. If it's youtube, click the youtube icon and paste it in, then delete everything before the = This will link the youtube video right on the forum.

I just have the video on my phone so i dont think i can upload it. I think my exhaust sounds great and I have no drone inside the cabin which is a big thing for me. I hate that humming sound while cruising down the highway. I would really like to keep the Top Speed Exhaust. Even though it might not be a really big name like Tanabe or stillen, the fit and finish are just as good IMO....

upload to youtube, and host it from there.

I've been trying to upload the video to YouTube but it won't upload for some reason. I'll try to do it from my laptop when I get home.

Hey how's the drone with the Tanabe exhaust? Is that the Medalion?

Yeah, it is the Medallion. I get a very minor drone at 2300-2600 rpm if I remember (It's been 6 months). It's mostly because the long tubes, not the Tanabe. Whatever 43-52 mph is in 6th and only under load. I admit though I opened a similar thread in the forced induction section because when pushing 500whp, that 2.75" restriction may become a factor. Naturally aspirated though, I wouldn't even worry.

Edit: click on my build thread, I have an 8 minute video where I drive and the camera is in the cabin, turn it up good speakers or headphones. I try and hit all the rpm points and show any drone in the exhaust. I'm not sure how well you'll be able to hear it.

The Medalion looks really nice and sounds great! I'm thinking about maybe going with it in the near future. I went a head and got the Tanabe y pipe. It matches up perfectly with the Top Speed exhaust. Plus, I feel like I gained back some torque down low since the tanabe uses smaller pipping. So now when I decide to go with the Medalion it will all match. Also, I have another question for you. Looks like you have a lot of experience with modding these cars. Right now I'm running Z1 maf tubes with K&N drop ins. I'm really interested in going with the Injen air intake. Do you think it would be better than what I have now?

Yes, but won't be dramatic. Mostly in the top half. For a better deal than Injens, look at Akuma, AAM's new CAI or AEM's which I run. Stillen G3's are the forum favorite of course. Peruse the FS section, sometimes you find good buys. I would post that Motordyne Y pipe in the FS section ASAP, recoup your funds. If you go Tanabe, it isn't cheap, but it's nice. My car sounds a fiercer than most others because the headers though.

I'd rather go with the Injens or Aem's so I don't have to cut anything. What's the difference between the Injens and Aem's? Looks like with the Aem's you move the maf.

The Injen CAI necks down at the MAF to the stock diameter. AEM's don't neck down and use their ETI technology to try and correct the MAF voltages. Works fairly well and you don't need to tune it to make intakes work.It also helps preserve older tunes as we know ECU's like to have a mind of their own.

I also see your Tanabe Y pipe is for sale haha. Is there going to be a Motordyne and Top Speed sale also? :)

If it did, there wouldn't be a need for the OP would there? :rolleyes:


Anyways, honestly you're better off getting both the Y Pipe and exhaust from the same company to prevent problems like this from happening. This is the risk you take when ordering different parts from different places. I would call your Top Speed part vendor back and ask if you can swap it for a different one. Either that or sell it and get the matching Y pipe. Or sell the exhaust section and get the Top Speed one. Or sell both and get a complete CBE all at once. There are options, but it will mean you'll need to swap one, the other, or both pieces you have now. :ugh2:

I just finished piecing my exhaust together. I'm running stock cats, a resonated motordyne xyz, and the Tenabe medalion. For the intake, I have k&n drop ins and z1 tubes. It sounds great but there is a drone around 2.5k under load. A downshift fixes that right up.

I got it tuned, uprev, and I'm putting down 294 whp. My base with everything installed was 273. I know tp's will open it up more, but it will also increase the dB's. after installing the exhaust I did see a noticeable increase in power. I was surprised at the 273 base, but I'm happy with the car now.