http://www.rallysportdirect.com/Tome...pipe-Big-Mouth

you guys think its gonna be better then the AMS performance downpipe ???

it is cheaper in price but i wanna know if it gonna have more flow then the AMS downpipe.

 

go with ams

 

One positive of the Tomei is the slip-joint. I've seen several cars where the cat (or test-pipe) and the front half of the mid-pipe ended up slightly lower than where a rallycrosser would like it. The slip joint would allow you to raise the front part of the exhaust as high as heat will allow.

I see no other positives. Shiny things don't do much for me, for example.

 

I had the exact same question as you a few months ago.


The Tomei is a really nice piece. The two piece design probably makes the install a little bit easier, but probably not significant. Still looks to be a 3 inch deisgn. Tomei make very high quality/fitment pieces, so that shouldn't be any issues. Tomei has also been R&D'ing evo x parts for years, so it's safe to say they have dialed in the exact design to their liking before releasing it.


The AMS downpipe is a one piece cast design, so there's no worries about cracking/failed welds(highly doubt this is an issue with tomei's sexy welding). Also a 3 inch design. AMS has been proven to be a really nice downpipe with upgraded stock frame turbos.


I chose the ams downpipe for one reason... more or less an assumption.

All jdm downpipes are usually not 3 inch designs because of some clearance issues with the RHD models. Some small exceptions like Garage G Force and Tomei maintain a 3 inch design, but pictures look like they add an extra bend/route to the piping for clearance of a larger diameter pipe. This is probably a very, very small detail to make a decision, every little bit counts.


Most dynos show that the o2/dp mods only show a very marginal gain at best on a stock turbo. I think the PITA factor must be considered when installing this piece. If you plan on upgrading to another stock frame turbo, I would recommend doing the install then.

 

Having been to Tomei's facility in Japan recently after the Tokyo Auto Salon I haven't seen so much R&D put into one part before in my life. They have an excellent staff with tons of experience. They aren't called "The engine specialists" for no reason. I've been friends with Tomei USA for a year or so now and have come to realize the reason why Tomei is always late to the game on parts is because they take their time to R&D every part, this include engine dynoing, install and removal during durability tests and all their parts are made and assembled in a temperature controlled room..

With that being said I am also a big fan of AMS, they make a very stout Evo X motor and have the numbers and following to back their products. They may not look the prettiest but they sure to get the job done and then some. The AMS Widemouth is more popular amongst the US Evo community and definitely worth the money. When it comes down to it I think its just a matter of supporting either company in their part, the Tomei is a bit easier to remove and install however the AMS definitely will hold up to whatever you throw at it. Its beefy in construction and I don't see any issues with durability of the unit over long periods of abuse. As for power, I have dealt with the AMS Widemouth and it puts down a good amount of flow to the exhaust setup, I have not however dealt with the Tomei yet and would love to get one in to see how well they perform. It would be quite interesting to see a direct side by side test on the unit.

Sorry for the essay...

 

Ams

 

Tomei has the JDM 2.8" flange at the end i was told
haven't seen one to verify yet.

 

Wow interesting thread. I was actually thinking of going with Tomei expreme downpipe since I do have their catback & test pipe. I couldn't decide which one to go with. The choice were Tomei expreme downpipe or o2 dump.

I'm guessing no one has install Tomei downpipe yet.

 

Go with the AMS Widemouth DP. You won't regret it

 

Go with the MAP 02 dump

 

Thinking about picking this up as well, but not looking forward to the install.

 

Map DP here also. just so you know, you can change your DP without changing the O2 housing. beside it being chrome, your never gonna see it unless you stick your head in there. go with a proven design and one that those of us have and are happy with... AMS, ETS, MAP all are great products, not all same price, but about same results in the end.. these are O2 housing replacement with DP.

 

You guys dont have to worry about clearance issues like RHD cars, so you might as well go a big/free flowing as you can and go with AMS.

 

So there's really no need to replace the O2 housing if there really isn't any gains from doing so right? Probably would cut the install time in half, which would save the headache and I wouldn't need to bust out the swear jar.

 

There are some gains for replacing the housing. But some can't justify the difference in gains vs difference in time to install. If you change out housing yourself, plan on at least 4 hrs if all goes smooth and use a lift if you have access to one. Ams has good write up, same install for all housing replacement dp. If you do from housing back, it is 4 spring bolts. Two on each end, bout 30 min job. Mine too 5.5 hrs to do.