nota4re

Here's a few pics for those who haven't managed to wiggle underneath a SH-AWD.

This first pic is of the rear "differential". Clearly the size alone would tell you that there's a lot going on here - not just an ordinary diff.



This next picture is of the all-aluminum engine carriage. It's a nice piece and I'm sure the engine & trans are all mounted to this carriage and then bolted *up* into the car along the assembly line.

A couple of other things to notice. The oil pan is a cast aluminum piece. The oil filter (not visible) is to the immediate right of the drain bolt near the passenger A-arm. Also not how the passenger side exhaust traverses forward and then has to awkwardly join the exhaust in front of the flex joint. (Doesn't seem ideal for HP.)




This next pic shows where the exhaust splits just aft of the third cat. Note that there's a vertical cat on each exhaust manifold (no visible).



Here's a close up of how the exhaust splits immediately aft of this third cat. (I've done better welds than this OEM example while drunk!)



Working our way back, there's two large resonators to further quiet the exhaust before going into the very large mufflers immediately inboard of the exhaust tips (not shown).

Wavehogger

Great job on the pics! I'm not impressed with the enginering on how the passenger downpipe connects either. It certainly looks like that is going to slow things down. It's pushing all that pressure into a slightly curved wall. With all the restrictions up front I think they wasted their time going to dual exhaust after the last cat. By that point there is already so much restriction.. I hope someone comes up with a complete downpipe-back system that will open her up. Though they haven't left much room up front so I don't know what can be done.

Colin

I most cases, Honda/Acura uses dual exhausts for the combination of flow and quietness. They need X amount of flow and to get it with one muffler, they would need a HUGE muffler, thus the duals. The restrictions are typical for this installation, I believe all the J series engines with the integrated (in the exhaust manifold) catalytic converters are like this.

Colin

The insides of the rear diff

crxb

nota4re thanks for the pics!

that tie in is not the greatest is it

I thought they went to 2 pipes to the aft - maybe easier than one larger one to package?

CleanCL

iTrader: (4)

You see what I see... January I will be running a true dual exhaust. Say goodbye to that horrid down pipe and 3rd cat. Stay tuned for dyno numbers.

On a side note, the catback (from the 3rd back) looks pretty clean to me. The only thing I'm not sure about are the resonators, but Acura claims a 17% increase in flow from the 3G Type S exhaust system. I don't think I'll be touching the rear section.

Legend2TL

Thanks for posting the pictures. FWIW, the exhaust pipe welds on my 3G TL look just as bad.

Is the rear suspension a coil over shock or are the suspension coil spring and shock separate? I was looking at the drivetrain picture in the 4G brochure and it looked like they were separate but was hard to tell from the picture.

Bearcat94

You're going to run true dual from the primary cats all the way back? Or from the A-Pipe (aka J-Pipe) back?


The A(J)-Pipe design is similar to the 3G and yes there is quite a bit of gain on the 3G when replaced with a less restrictive design. Call it about 10 WHP. Add'l gains from A(J)-Pipe replacement with 3rd delete and cat-back exhaust (say 15WHP from the A(J)-Pipe replacement PLUS whatever you get from the exhaust and 3rd cat delete).

Overall, the 4G looks MUCH more free flowing from the 3rd cat back than the 3G.


3G TL ATLP A(J)-Pipe After Market Replacement:





3G A(J)-Pipe OE Side-by-Side with ATLP After Market:





IOW - if you guys can get someone to fabricate a better A(J)-Pipe design and/or a test pipe to relace the 3rd cat, you might be looking at ~10 - ~15 WHP pickup.

Legend2TL

Wow, that's not your typically looking diff!

CleanCL

iTrader: (4)

I'll be running true dual, so from the primary cats back. This will replace the entire A(J)-Pipe and 3rd cat with some straight pipe, flex couplers, and x-pipe hooking right into the factory catback which I believe is already pretty free flowing. My opinion is that the A-pipe, factory or aftermarket, is a terrible design when it comes to exhaust systems. I'm sure there are gains to be had from a better flowing replacement, but I think the most gains are from a true dual setup with properly placed x-pipe.

Bearcat94

I agree, you'll do good that way. What size pipe is on the stock Cat-back? You going to run the same size from the primary cats?

Also, looking a little closer at the stock A-Pipe, the OE design looks more like the RichieV6 After Market design (again, 3G) than the 3G OE design. If so, the 4G A-Pipe is already more open than the 3G (especially where the 3G gets Crimped at the 2 into 1).