Test pipe

[dsmsolberg]

Just got my 3" HKS Hi-Power cat-back system. Pretty excited to throw it on, but thought it would make sense to do the WHOLE exhaust at once... so I'm looking for a downpipe and testpipe. Had a few questions:

I saw a lot of the 3" (outlet) downpipes have 2.5 - 2.75" inlets. Is this normal? Will it bolt up to a 3" system? Is there a brand that the majority uses?

I couldn't really find many test pipes, seems people usually make their own. I did see that Megan makes one, and it sells on EBAY, but it doesn't list the inlet size. Are they all 2.5"? If they are 2.5", would they bolt up to a 3" system? Does anybody else sell them? Any recommendations?

MEGAN RACING TEST PIPE RESONATOR 95-99 ECLIPSE GST GSX | eBay

Thanks ^_^

 

[DSM_munky_man]

A 3" dp usually has a smaller neck were it comes down to meet the o2 housing. With a 3" neck cant bolt on to the o2 housing without modification. And if you put a smaller feet pipe it will be a restriction and hurt performance

 

[LiquidX]

You'll want to weld up your own test pipe as flange orientation from other companies doesn't always match up. Any exhaust shop can fit one however they will not install it as They cannot remove a working cat converter.

 

[anokh3]

The Megan racing downpipe comes with a 2.5" opening right after the o2 housing but quickly goes to 3" AND is a cat delete so you won't need a test pipe. Mine needed to add a 3" wide pipe in between though because it was 3.25" away from meeting up with my cat back exhaust (Apexi N1), but you can get a 3" pipe with flared inside diameter on one end from most local auto stores. If you're doing the whole exhaust then I think it'd be pointless to buy a megan racing test pipe when you could just get their downpipe which goes 3" all the way after the bottleneck to the cat back.

 

[dsmsolberg]

The Megan racing downpipe comes with a 2.5" opening right after the o2 housing but quickly goes to 3" AND is a cat delete so you won't need a test pipe. Mine needed to add a 3" wide pipe in between though because it was 3.25" away from meeting up with my cat back exhaust (Apexi N1), but you can get a 3" pipe with flared inside diameter on one end from most local auto stores. If you're doing the whole exhaust then I think it'd be pointless to buy a megan racing test pipe when you could just get their downpipe which goes 3" all the way after the bottleneck to the cat back.

Thank you very, very much, I didn't know the dp was a cat-delete (or that it was THAT long). Extremely happy I didn't end up buying both just to send the test pipe back

So the only thing it really boils down to is the downpipe manufacturer... Any reason to go with the Apex'i vs the Megan, vice-versa, or another brand completely?

Thanks again.

 

[GMCometh]

A lot of people seem to have fitment issues with the Megan downpipe...other people don't. I guess it's the luck of the draw.

Do you have emissions testing in your area?

 

[anokh3]

I've got another friend that used the MR downpipe with no problem (like I said the only issue I had was it was 3.25" too short, but the flange to the exhaust was fine and the DP comes as two pipes so you can easily add an attachment in between from a local shop). For reference though, the Apexi are NOT cat delete. I called them to verify this before I ordered the Megan Racing.

Also, the DP seemed REAL REAL close to touching the oil pan. As in close enough I couldn't fit a sheet of paper in between. But there wasn't any vibration when starting her up, and hasn't been any problem driving it around in the two days I've had it on. But, I'd be sure to keep in mind that you might have to play around with it and it might not be directly bolt on, but shouldn't be too much work...Goodluck.

 

[dsmsolberg]

A lot of people seem to have fitment issues with the Megan downpipe...other people don't. I guess it's the luck of the draw.

Do you have emissions testing in your area?

I don't, but might be moving somewhere that it is mandatory.

 

[GMCometh]

I've got another friend that used the MR downpipe with no problem (like I said the only issue I had was it was 3.25" too short, but the flange to the exhaust was fine and the DP comes as two pipes so you can easily add an attachment in between from a local shop). For reference though, the Apexi are NOT cat delete. I called them to verify this before I ordered the Megan Racing.

Also, the DP seemed REAL REAL close to touching the oil pan. As in close enough I couldn't fit a sheet of paper in between. But there wasn't any vibration when starting her up, and hasn't been any problem driving it around in the two days I've had it on. But, I'd be sure to keep in mind that you might have to play around with it and it might not be directly bolt on, but shouldn't be too much work...Goodluck.

According to extreme psi, the apexi's do replace the cat......

I don't, but might be moving somewhere that it is mandatory.

Go with a RRE short downpipe with both a test pipe and hfc. You can have the best of both worlds.

They have great reviews

 

[anokh3]

According to extreme psi, the apexi's do replace the cat......

Thats the problem, extreme psi says they do, a few other sites say they do and a few say they don't...hence why I called Apex'i in Cali to confirm that it was NOT cat delete. Maybe a previous version was cat delete...but the current N1 DP, (and I believe GT) are not...but if you don't believe me then I'd call them too, always better to hear it straight from the manufacturer.

Go with a RRE short downpipe with both a test pipe and hfc. You can have the best of both worlds.

They have great reviews

I had the RRE short DP w/hfc before....absolutely no problems with it and would recommend it to anyone. If you have emissions concerns then the best route. I just got the straight pipe because I hooked my wideband up to the rear o2 and use ECMlink to disable the codes.

 

[russ96gst]

^^^^ plus one on that, order the RRE "short" down pipe and a test pipe, from Roadraceengineengineering.com thats what I have, fits perfect and is 3" after the flex section.

 

[GMCometh]

I ordered my RRE and test pipe yesterday. I'll take some pictures of the install for everyone's viewing pleasure

 

[dsmsolberg]

According to extreme psi, the apexi's do replace the cat......



Go with a RRE short downpipe with both a test pipe and hfc. You can have the best of both worlds.

They have great reviews

Is there a big power loss between the long downpipe and the short dp/high flow cat combo?

 

[my dreamt dsm]

I emailed megan and they say their down pipe will not fit the hks hi power. Their dp are 3 inch outlets which will not bolt up to the 2.7inch of the hks. You will have to weld and cut the hks with a 3inch to fit.

Check my post with the link.
http://www.dsmtuners.com/forums/newbie-forum/403039-exhaust-fitment.html

 

[dsmsolberg]

I emailed megan and they say their down pipe will not fit the hks hi power. Their dp are 3 inch outlets which will not bolt up to the 2.7inch of the hks. You will have to weld and cut the hks with a 3inch to fit.

Check my post with the link.
http://www.dsmtuners.com/forums/newbie-forum/403039-exhaust-fitment.html

Well, that's def 1 option down haha. I'd rather not hack up my new cat-back system... does anyone know if the Apex'i bolts up?

 

[GMCometh]

Is there a big power loss between the long downpipe and the short dp/high flow cat combo?

I've read where people say that they can feel a huge difference when they eliminate the cat...others say they can't tell at all. The only way to truly tell would be to dyno the car with and without the cat.

I just passed emissions last week, and don't want to shell out the extra $200 for a hfc right now, so I'm going with a test pipe for the time being. I'll be purchasing the cat later in time.

You might as well get both....

 

[Kapok6]

Like GMCometh stated above, the Apex DOES eliminate the cat, at least the N1 series does. I have owned 2 sets, my buddy owned a full N1 as well, and I would never use anything different for a DSM. It fits better than the stock exhaust. I LOVE the N1.

The Buschur Racing test pipe, at least the one I saw was pretty neat as the flanges could be rotated so bolting it up isn't really an issue.

 

[anokh3]

Like GMCometh stated above, the Apex DOES eliminate the cat, at least the N1 series does. I have owned 2 sets, my buddy owned a full N1 as well, and I would never use anything different for a DSM. It fits better than the stock exhaust. I LOVE the N1.

Seems there are mixed signals about the N1. I definately believe everyone saying that it fits obviously if they have it and it fit their cars. However, as I stated I called Apex'i about it and it was not cat delete for my '99 GSX. I don't want to point you in the wrong direction though so if you like the Apex'i then I'd call them yourself, they are very helpful. Instructions can also be downloaded from their website, which also state that the downpipe only goes to the cat (again this may only be because I looked at the 2G GSX setup). Still, maybe Kapok6 has older models of the DP. Hope I'm wrong, but always best to double check w/the manufacturer. Also, if it really comes down to it, make sure that you can return it if it doesn't fit exactly how you want or if it isn't a cat delete

And if in doubt RRE is always a good fit, though I had the old unit (like from 10 years ago) which needed to weld a flange between the DP and the HFC. But i'm sure its fixed now and don't mean to scare you.