Fast Intentions resonated cats w/IPL OEM exhaust
 

I'll be adding more to the review as I put miles on the car and I'm actually able to "test" them fully (bad weather here currently).

I installed a set of Fast Intentions resonated high flow cats on my IPL with a 100% stock exhaust. I went with the resonated HFC's to keep noise down as the IPL exhaust already has some meat to it.

Starting off with the bad as this may be a concern to most folks and I think FI should update their design.

First, there are no brackets to bolt up to the stock exhaust hanger. That leaves all the weight on the header bolts going back all the way to the rear section before there are any muffler hangers. It most likely puts additional stress on the various exhaust welds. There's been at least one case of the FI's failing on this board.

Second, due to the lack of support brackets, there's more vibration at idle in the cabin. You can feel it in the seat, steering wheel and shifter. This goes away just off idle. I didn't notice any extra vibrations at speed.

Third, due to the placement of the 02 J-bung (It's shaped like a J), the OEM 02 sensor wire retaining clips are no longer functional. You'll have to zip tie them to the clip as there isn't enough length to run them through the clip properly. I'll take photos of this later.

Fourth, the instructions are fairly basic with no torque specs or images. So be prepared to do a bit of homework ahead of time.


Now the good. They look to be very well-made, solid welds, the inside has been cleaned up and smoothed to help flow and they're lighter than the stock cats by a few pounds.

The sound on startup is a bit deeper and louder when cold and then quiets down as the car heats up. Once warm, the exhaust note is a bit more defined in that you can hear the individual exhaust pulses. The IPL exhaust is a true dual exhaust and at no point does it merge into one exhaust tube.

I had very little road time and couldn't get on it due to rainy weather. It's a bit louder over a 250rpm range from say 1600 rpm to 1750 rpm when lugging it in a tall gear. It's not annoying but it is louder than the stock exhaust. Once through that rpm range, the lower base of the exhaust note disappears in the cabin and the higher pitched end of things is a bit louder and more defined than stock. It's not much but it's there. I was only able to take it up to say 4500 or 5000 rpm at part throttle. Sound very authoritative but I felt the IPL exhaust did anyway. None the less, as of now, I'm pleased with the change in exhaust note. To put it bluntly, it sounds pretty damn good.

The car did seem to rev more freely and I needed less throttle input to get things going more rapidly. I did not reset the ECU.

I'll update this portion once I have some decent drive time and the weather clears up. Looks like it'll be at least a week if not more. Perfect timing. :52:

Installation, theoretically, is very straightforward. It's not rocket science to install these but it entirely depends on the condition of your stock exhaust bolts. If you live in the rust belt and have salty winter roads, do not install these yourself and take it to a pro.

Fortunately I have a low mileage car and live in the South. I did two different applications of PB Blasters ahead of time and then an additional application of a 50/50 mix of acetone and brake fluid. Any home improvement store will have acetone in the paint section. While you're at the store, pick up a bit of clear tubing, about 3ft., along with a long wooden dowel if they have it. You'll use it to apply the rust breaker fluid to the bolts which face the front of the car and are accessed through the engine bay. A syringe is also a good idea as it's a bit more precise than a spray bottle and you can attach it to the clear tubing as well. I used a brush to dab on the mixture from below the car.

for the clear tubing and wooden dowel rod, tape the tubing to the rod at various locations so it stays straight and is rigid. Place one end of the tubing on top of the "demon" bolts and squirt a bit of the rust breaker mixture on top of them. Make sure it hits the area where the bolt flange contacts the exhaust flange mating surface. Do this on the lower bolt that's visible from the engine bay as well.

I also bought three small LED adjustable flashlights which helps in the visibility dept. and provide precise light where needed.

The rest is just following the directions or doing the reverse of removal.

DO NOT USE AN IMPACT GUN. It can damage 02 sensors and they're expensive to replace. Even if you've removed the two in either cat, there's one in both headers.

I could not find torque specs for the cat to header bolts. I went with 48ft/lbs. I believe all the other bolts are 35ft/lb and the 02 sensors are 45ft/lbs.

My next to do list is to help support the cats with metal zip ties on the stock exhaust bracket. This is a temporary step until I can get a shop to weld up some brackets.

I'll have a few photos and other details to add later.

And to clarify, I am, so far, happy with the purchase. I feel with their cost, they should be the best engineered on the market. But with no exhaust bracket, that's just not the case and it'll take extra effort from the end user, not to mention cost, to get these up to OEM snuff.

Ok I'd did some data logging of air/fuel and the FI RHFC's did lean the car out over just the Nismo intakes. It's still into the 10's by 5200 rpm and the a/f curve isn't as smooth so the ECU may be learning. This was my first WOT run to redline. Feels great in the low/midrange but falls flat up top.

Attachment 132511

Thanks for this^^^ good tips throughout your R&R process. Look forward to your DIY bracket/clamp/steel tie fix too.

Yeah am definitely going to need a tune to take advantage of these "power" mods. Hoping the zip ties arrive today so I can put them on tomorrow morning. Will take photos.

Zip ties did arrive yesterday and it's a no-go on using them in any sort of support role.

Problem number one is the end of the bracket hits the 02 bung on one side. There's a small gap on the driver's side but none on the passenger's side. Theoretically, I could finesse the bracket a bit more and open up the gap between the bracket end and the 02 bung but the zip ties aren't going to do a lick of good.

While I was under there, I made sure the cats were aligned properly with the exhaust. It was more of an eyeball job but I seem to be pretty precise when doing things that way.

I'll reiterate the car is louder on cold startup but quickly settles into a mellow idle once everything heats up, expands and fully seals. Other than the more defined idle burble, you'd not know it was modified in any way.

Zip ties. Yep, not going to do a damn thing.
Attachment 132479

Driver's side, can't really see the gap between the support bracket and the 02 housing but it's there.
Attachment 132480

To me, it looks like there should be a bracket there, somewhere, supporting the exhaust.
Attachment 132481
Attachment 132482

I'm not sure if they're hard rubber or plastic, but those black blocks, can't seem to see any actual purpose for them. They "look" like isolators but they're not attached to anything other than the exhaust piping.
Attachment 132483

Looking up at the header to cat connection. They turned that color after two days (perfectly normal).
Attachment 132484

Here you can see where the bracket that normally supports and holds the 02 sensor harness is no longer in the right place and the wiring harness isn't long enough to loop back through it. Probably a small price to pay for no codes. Theoretically you could move it up one bolt but those are oil pan bolts and I'm not touching them with a ten foot pole. If there's one thing I hate, it's an oil leak.
Attachment 132485
Here's a shot where you can see both the RHFC's complete with FI's logo.
Attachment 132486

Pre-installation shots showing the ground down innards to provide unrestricted, turbulent-free flow.
Attachment 132487
Attachment 132488
Attachment 132489
Attachment 132490
Attachment 132491



I'm going to do a preliminary rating.

For performance, I'm going to give them a 10 assuming they work as advertised once the car is tuned.

For engineering, I'm going to give them a 6. I'd like to see that lip, like the stock cats, to prevent alignment issues and I'd like to see them properly designed with a bracket and more clearance between the OEM chassis to cat bracket and the 02 bungs.

For sound, 8 out of 10. I hear a bit of rasp in the video but the car isn't under load. I don't hear rasp when in the car under full throttle. Here's an at idle video, I have a second but it's still processing and I'll post it later:

Second video, the car's still not fully warmed up so I did not want to rev it much. I have a steep driveway. Looks like an up the skirt shot, LOL.

The rubber black blocks on the exhaust isolate vibration. They are very useful in my opinion.

As for the missing brackets on all these hfc and resonated tp etc etc, I see tons of people complaining about the added vibration yet every company I have contacted basically says the forum members are lying lol "the brackets aren't needed and there is no added vibration" is what I have heard from MULTIPLE vendors/manufacturers.

I really think the bracket is necessary and I think when I get resonated tp I am going to order the ebay ones and have a shop build me a bracket with the money saved. It is a shame because I would much rather purchase from a forum vendor :/

I only get vibration at idle, more so when it's in gear. I should do the water test and balance a clear glass of water on the center console. It'll clearly show the vibrations.

Both Berk and Z1 have brackets but they're not resonated.

Correct, but again, not resonated. Straight through pipes seem to make undesirable sounds with our motors or at least from what I have read.

Another WOT run, feels a bit more even acceleration wise but lots of power to be had with a tune. Attachment 132478

Yeah I was worried more about overall decibel level and I don't seem to have the hiss. Sounded really good at WOT, have to admit. It's more towards the exotic side.

Yea these G's have always sounded amazing. I bet it is perfect with that ipl exhaust. If you decide to do anymore videos like in car at different throttle levels or driveaways/bys I would be definitely interested in watching *subtle hint* lol

I'm going to try and do a few more vids, may borrow a Go Pro from a friend otherwise I'll use a 5d MkIII and shotgun mic. Just more work that way. I've got Final Cut Pro too.

Did my first long distance cruise with these and they pass the wife test. In fact at speed, say 70-80mph, the car is actually a bit more quiet than with the stock cats.

Agreed! Not a noticeable enough change in sound for my taste. I had the same setup.

Thanks for keeping this updated & glad it passed the wife test too!