MegaZip and TRD Diffuser MS342-18003

[Bergycheese348]

I have a FR-S and am doing a functional TRD build. Looking at the forums, it looks like the diffuser (MS342-18003) would make sense in decreasing drag due to the flat underside and big hole near the muffler, and of course channel the air to help create downforce (by making wings and such more efficient). It is supposed to be applied with the Japanese TRD quad exit exhaust, which I have the US Spec TRD dual ‘D’ exit exhaust, which having the Japanese TRD exhaust is beneficial because the diffuser is designed to attach to it. People have said there should be some way to make it work, but does anyone know of anyone that has it installed without the Japanese spec TRD exhaust?

Secondly (not sure where I should have put this), does anyone have any experience with MegaZip? The aforementioned diffuser is listed for a reasonable price to what it would have costed new from TRD Japan, which is half what evasive motor sports is selling it for, and shipping from the UAE is only $31 USD for that bully of an item? Reviews online are mixed, but with a Supra, a 4Runner, and a Honda motorbike forum, people generally say it’s legit as long as you contact them and they for sure have the part.

Any suggestions/comments would be appreciated. Thanks!

[RayRay88]

It’ll decrease drag a bit but nothing like a properly designed and tested full diffuser like the verus kit. If you’re looking for something tangible look elsewhere. If budgets an issue you can always fab your own. With a relatively low diffuser angle, some wool tufts and a go pro you can do wonders. I would read up heavily on aero and what exactly you’re trying to accomplish before you set out. The internet is great for ideas (both good and bad) but you’ll want to lean into textbooks and proper literature.

[NLSP]

I haven't seen anyone mount the TRD diffuser on a non-JDM TRD exhaust, but hopefully this gives you an idea of how it works and how you could possibly make it work.

It's mounted with 4 screws - the diffuser has 4 tabs for the screws to go through, and the muffler itself has 4 threaded tabs for the screws to thread into.

The TRD USA muffler is a totally different size and shape, so you'll have to come up with some other way of mounting it on, maybe some kind of brackets attached to the heat shield above the muffler.

[sygfrid]

If you really want to create downforce & reduce drag, you may want to reconsider Verus Engineering's Diffuser as mentioned by Rayray88. Better yet, get the entire Verus's underbody system (transmission tunnel cover, differential & suspension cover, & rear diffuser) and the JDM aero under panel covers to really have a more flat underbody so that the clean air can attach & pass through the flattened bottom to create downforce & reduce drag.

Why do you want to go with Verus's Diffuser? It's a huge panel that covers the entire rear bumper's bottom, even the exhaust, & not just the middle portion of the exhaust just like TRD's. If you look at the rear bumper, the exhaust area is almost like a parachute where air can get trapped & cause drag. Verus covers this huge air stagnation area & allows the low pressure air from the mid underbody to exit cleanly towards the rear.

[saltywetman]

Originally Posted by NLSP

I haven't seen anyone mount the TRD diffuser on a non-JDM TRD exhaust, but hopefully this gives you an idea of how it works and how you could possibly make it work.

It's mounted with 4 screws - the diffuser has 4 tabs for the screws to go through, and the muffler itself has 4 threaded tabs for the screws to thread into.

The TRD USA muffler is a totally different size and shape, so you'll have to come up with some other way of mounting it on, maybe some kind of brackets attached to the heat shield above the muffler.

There's blitz nurspec vs/vsr quad tip and fujitsubo rm+c quad tip catbacks that were made to go with the rear trd bumper if you want an aftermarket midpipe instead of just an axleback. However it's just as much or more than the TRD stuff

[Z06ZN6]

Hi. I bought from Megazip before back at the end of 2019. I had no issues and would buy from them again. They were very responsive and helpful. They even let me know when they were going to be closed for holidays.

From Megazip I bought an OEM LHD black with silver stitched parking brake handle and boot that was discontinued here in the US. Not sure if they are available here again but back then they were discontinued and Megazip said they could get them for me. They were a little more expensive then equivalent items in the states but the extra price was ok because I really wanted to get a hold of the discontinued silver stitched parts to fix Toyota's mismatched shift and parking brake stitching colors. My 86 has silver stitch everywhere except for some reason they used black stitch on the parking brake. Now the shifter, parking brake and console lid stitching all matches and I sleep well at night again.

[Bergycheese348]

Originally Posted by Z06ZN6

Hi. I bought from Megazip before back at the end of 2019. I had no issues and would buy from them again. They were very responsive and helpful. They even let me know when they were going to be closed for holidays.

From Megazip I bought an OEM LHD black with silver stitched parking brake handle and boot that was discontinued here in the US. Not sure if they are available here again but back then they were discontinued and Megazip said they could get them for me. They were a little more expensive then equivalent items in the states but the extra price was ok because I really wanted to get a hold of the discontinued silver stitched parts to fix Toyota's mismatched shift and parking brake stitching colors. My 86 has silver stitch everywhere except for some reason they used black stitch on the parking brake. Now the shifter, parking brake and console lid stitching all matches and I sleep well at night again.

That’s good you can sleep at night😂. It’s just one of those sites that look risky, but may be legit at the same time. Also, those shipping costs are just super weird😅

[Bergycheese348]

Originally Posted by RayRay88

It’ll decrease drag a bit but nothing like a properly designed and tested full diffuser like the verus kit. If you’re looking for something tangible look elsewhere. If budgets an issue you can always fab your own. With a relatively low diffuser angle, some wool tufts and a go pro you can do wonders. I would read up heavily on aero and what exactly you’re trying to accomplish before you set out. The internet is great for ideas (both good and bad) but you’ll want to lean into textbooks and proper literature.

To my understanding, it is a properly designed diffuser, and it has gone through a good amount of R&D like all other TRD Japan parts. Yes, I know it doesn’t cover the entire underside, but it covers the biggest area for drag. The Versus diffuser is too extreme for what I want at the moment, as it is my daily and MN winters are not good up here. The streets also suck, and the angles going into parking lots are horrible. That’s why the TRD interested me, since it isn’t extremely hardcore and sitting really low (so it doesn’t get destroyed), but it does the job I want it to do. Hopefully my reasoning makes sense!

[Bergycheese348]

Originally Posted by NLSP

I haven't seen anyone mount the TRD diffuser on a non-JDM TRD exhaust, but hopefully this gives you an idea of how it works and how you could possibly make it work.

It's mounted with 4 screws - the diffuser has 4 tabs for the screws to go through, and the muffler itself has 4 threaded tabs for the screws to thread into.

The TRD USA muffler is a totally different size and shape, so you'll have to come up with some other way of mounting it on, maybe some kind of brackets attached to the heat shield above the muffler.

That image really helps! When reading before I was wondering what it meant when it said ‘for use with the TRD Diffuser (Japan spec)’, but it makes sense now. The question is how hard would it be to get that to work, since I’m 17 and don’t have welding tools…

[RayRay88]

Originally Posted by Bergycheese348

To my understanding, it is a properly designed diffuser, and it has gone through a good amount of R&D like all other TRD Japan parts. Yes, I know it doesn’t cover the entire underside, but it covers the biggest area for drag. The Versus diffuser is too extreme for what I want at the moment, as it is my daily and MN winters are not good up here. The streets also suck, and the angles going into parking lots are horrible. That’s why the TRD interested me, since it isn’t extremely hardcore and sitting really low (so it doesn’t get destroyed), but it does the job I want it to do. Hopefully my reasoning makes sense!

Calling it a diffuser is semantics, but in my opinion it is most definitely not a true diffuser, more an underbody panel.

First of all the throat starts half way through the muffler. It has no real expansion and the angle looks too shallow. There's also no real clean airflow feeding it. It's a shiny piece of TRD bling.

You could probably have a metal shop fab you up a similar piece for probably a fraction of the cost. It would perform identically.

If you're set on this piece than by all means go for it. Just please don't try to convince yourself (and others) that it's nothing more than a garnish. You'll decrease drag ever so slightly (probably imperceptible). But you won't gain any sort of massive stability or drag reduction. You would be surprised how little R&D goes into most of TRD japans garnishes/aero pieces. Even some of the GR stuff looks very much in the "looks cool/could maybe do something" category.

Stuff like the verus diffuser is very well thought out and backed with physical/CFD data. Perhaps others with the diffuser can chime in but the non aggressive version should be relatively easy to clear around town unless you're dealing with extreme departure/approach angles or you're dumped low.

This is definitely a real diffuser and well thought out/designed TRD Japan part:


Also to be clear the (suit case) muffler is the least draggy part of the entire rear underside. It self alone does decently for drag reduction just by being that shape and where it is.

[Bergycheese348]

Originally Posted by RayRay88

Calling it a diffuser is semantics, but in my opinion it is most definitely not a true diffuser, more an underbody panel.

First of all the throat starts half way through the muffler. It has no real expansion and the angle looks too shallow. There's also no real clean airflow feeding it. It's a shiny piece of TRD bling.

You could probably have a metal shop fab you up a similar piece for probably a fraction of the cost. It would perform identically.

If you're set on this piece than by all means go for it. Just please don't try to convince yourself (and others) that it's nothing more than a garnish. You'll decrease drag ever so slightly (probably imperceptible). But you won't gain any sort of massive stability or drag reduction. You would be surprised how little R&D goes into most of TRD japans garnishes/aero pieces. Even some of the GR stuff looks very much in the "looks cool/could maybe do something" category.

Stuff like the verus diffuser is very well thought out and backed with physical/CFD data. Perhaps others with the diffuser can chime in but the non aggressive version should be relatively easy to clear around town unless you're dealing with extreme departure/approach angles or you're dumped low.

This is definitely a real diffuser and well thought out/designed TRD Japan part:


Also to be clear the (suit case) muffler is the least draggy part of the entire rear underside. It self alone does decently for drag reduction just by being that shape and where it is.

I’m not sure I’d describe it as TRD bling like some of their stuff, as you definitely can’t see it lol.

When I said it must have gone through R&D, I didn’t mean it went through an extensive amount of R&D. It’s an item they knew they weren’t going to sell too many of in general not to mention it only worked on the one exhaust, but it also wasn’t used on a car made for R&D since it isn’t as aggressive as it would need to be to be on those R&D cars. Because of that it definitely had some, but probably not an extensive amount. An example of an extensive amount is probably their aero fins or their GT wing, both of which were applied to the Griffon concept R&D car. Those definitely went through R&D to make sure they performed well in every category. The wing itself is of an interesting swan neck design with its endplates and its braces that keep the trunk from collapsing. TRD knew coming into the design of this diffuser it wasn’t for a track specific car like the other diffuser you showed. Once again, I’m looking for one that is efficient but isn’t too aggressive as I still need to drive this car on a daily basis. I have a steep driveway where every car will scrape if it doesn’t go out at an angle. I’m lucky that my APR splitter (the one made for the RS1.0 lip) hasn’t scrapped yet, and I’m on stock suspension at the moment. These are MN roads we are talking about, which are pretty bad for the most part.

I’m just starting to crack into the world of autox, and I’d like to keep my class lower if possible. When I have more money and availability for an all out track car, the aggressive diffuser is where I will go. And my biggest concern is the fact that it doesn’t mount to the US spec TRD exhaust from factory, as I’m 17 and don’t have welding tools or the experience to weld it on😅.

And yes, I’m doing my best for research before just buying these parts, as I’m trying to be smart with money and with actually increasing performance in my car, hence why I’m asking the questions here. Cheers!

[RayRay88]

Originally Posted by Bergycheese348

I’m not sure I’d describe it as TRD bling like some of their stuff, as you definitely can’t see it lol.

When I said it must have gone through R&D, I didn’t mean it went through an extensive amount of R&D. It’s an item they knew they weren’t going to sell too many of in general not to mention it only worked on the one exhaust, but it also wasn’t used on a car made for R&D since it isn’t as aggressive as it would need to be to be on those R&D cars. Because of that it definitely had some, but probably not an extensive amount. An example of an extensive amount is probably their aero fins or their GT wing, both of which were applied to the Griffon concept R&D car. Those definitely went through R&D to make sure they performed well in every category. The wing itself is of an interesting swan neck design with its endplates and its braces that keep the trunk from collapsing. TRD knew coming into the design of this diffuser it wasn’t for a track specific car like the other diffuser you showed. Once again, I’m looking for one that is efficient but isn’t too aggressive as I still need to drive this car on a daily basis. I have a steep driveway where every car will scrape if it doesn’t go out at an angle. I’m lucky that my APR splitter (the one made for the RS1.0 lip) hasn’t scrapped yet, and I’m on stock suspension at the moment. These are MN roads we are talking about, which are pretty bad for the most part.

I’m just starting to crack into the world of autox, and I’d like to keep my class lower if possible. When I have more money and availability for an all out track car, the aggressive diffuser is where I will go. And my biggest concern is the fact that it doesn’t mount to the US spec TRD exhaust from factory, as I’m 17 and don’t have welding tools or the experience to weld it on😅.

And yes, I’m doing my best for research before just buying these parts, as I’m trying to be smart with money and with actually increasing performance in my car, hence why I’m asking the questions here. Cheers!

It's not about more aggressive or track/street specific anything. It's literally about functional vs non functional. If you're here to learn, that's great, but if you're here for yes men to make you feel good about a purchase then I shall graciously drop out of this conversation. I suggest you take a hard look at what a diffuser actually is and read up on the subject.

Also being 17, it's fun to idolize track focused concepts like the griffon, but the older you get and the more you learn, you start to realize these concepts are really just design and engineering exercises with a healthy sprinkling of bean counter corner cutting. Take it from someone who took Vehicle design in school and has been in advanced materials/prototyping manufacturing for a better part of a decade.