I have been doing some researching about the exhaust piping especially in the rear of the RC-F and stumbled upon something that caught my eye. There was a video I saw on Youtube where an RCF had PPE UEL/ Apexi Midpipe but what caught my interest was that the axleback portion was Invidia Q300 from an RC350. Has anyone else dabbled into the idea of using RC350 exhaust on the RCF? I'm mainly looking at the Remark Axleback because its essentially a muffler delete, plus I'd still be able to keep the oem system for future use if need be. Considering that most exhaust systems from both the RC350 and RCF are 2.5" pipe diameter. Food for thought I guess, sorry if this topic has been covered before and I'm beating a deadhorse...

Be gentle this is my first post!!

 

Welcome to the forum!

No, because the RC350 for the most part, is a different car so the parts don't match (about 70% according to Lexus) so generally people buy just RCF parts for it. The parts are designed differently. The exhaust flow characteristics of the RCF are different than RC350 so in order to properly benefit from an aftermarket exhaust, it makes sense to get one made for the RCF. I am not sure what the benefit would be to put RC350 parts on an RCF.

 

Yea, I get what you are getting at, I was just looking it from another perspective since I just wanted to do a muffler delete and retain the oem system for the future. Putting into consideration its just piping without the muffler it should be able to bolt up right considering the different difference between the RC350 and the RCF exhaust would be the internal bafflers inside the muffler. With all the piping diameter being the same size, I would have thought someone would have toyed with the idea after sometime now. But, I guess I have to bother the vendors now because the PPE muffler delete is looking tempting but out of stock haha.

 

What you were asking is a perfectly valid question. It may be better to see if a local exhaust shop would be willing to just perform a muffler delete if that's all you are after, no need for pre-fabricated parts.

 

I just looked at some stock photos of axleback exhausts and they look SUPER close. The only way to find out for sure is anyone who has tried it. As far as "specifically designed" for the RCF. Well, that's just a pipe dream. Exhaust companies make exhaust flow as well as possible and almost never make a muffler specific to an application. So the equation is the same for almost all exhausts: lower restriction, add resonators and mufflers that create a desired sound, add build quality and high end materials to increase cost and or reputation. It's usually one of their performance mufflers and tips matched up to custom mandrel bent tubing. I believe a RCF and GSF axle backs are almost identical yet the GSF is slightly shorter. The RCF is a Mash up of the front chassis of a GS and the rear section of an RC so it might be worth a shot. I wonder if any of the vendors on this site know. RR Racing might, it seems like they've done a lot of R&D.

 

GS was a 5-series competitor. RC/RCF is a foot shorter (185.2 in vs 193.5 in) than GSF so the GSF guys have to modify RCF exhausts like Invidia mid-pipe to fit the full length. RCF's monococque was created using GS front with some additional reinforcements (for long hood/fit the V8 engine), IS-Convertible mid-section (for a very stiff core) and rear from the 3rd gen IS (for compact dimensions/shiort overhang).

Another interesting thing, though GSF and RCF have the same front end, the 4-point strut braces in the RCF don't fit the GSF. No knows why.

 

Looking at the Remark site and the muffler delete pipes to which you are referring I noticed this right away... * Does not fit RC-F (V8) So yeah, PPE is only option for a bolt on delete I know of.

 

This is the video from where the idea came about. But interesting to know the structure of the RC-F especially with the rear section being used from the 3IS.

 

RCF piping is 2.75 inches all the way through with Invidia so that is difference that jumps out right away that the RC350 Invidia has a 2.5 inch diameter.

 

From all the exhaust that I've seen Invidia is the only one with 2.75" pipe diameter. Apexi, Ark, RR racing list their pipe diameter on their exhaust systems to be 2.5" in with various diameters when it comes to the tip. The only other one I've seen with a 2.75" pipe diameter is the Revel/Tanabe axelback exhaust. Unless I just answered my own question there since in the video the person was using the Apexi midpipe which has a 2.5" pipe diameter that's why he was able to use the RC350 2.5 axelback? HAHA did I open another pandoras box of questions?

 

Has anyone figured this out yet?

 

So its all about compatibility and interchange. Forget about 'pipe size' and 'diameter'. It's all a lie. Why do I say its all a 'lie'? Simply because they all list the maximum pipe diameter, is that inside or our outside? What they dont tell you is that they all taper down.

I was wondering if the RC 350 Performance exhaust would my RC F and from what I can tell is yes, it'll bolt up. I came to this conclusion based of the simple fact that the RC350, RCF and FE/TE cars all use the same muffler donut which means the pipe size at the location is the same. Its Lexus part number 17451.

I'm not an expert on all exhausts so I'll only comment on what I know...

Apex'i RCF axle back bolts right up. Easy, easy
Invidia RC F axle back: As far as I can tell they dont make RCF axle back but...the axle pack from a full system does NOT bolt up. Pipe diameter is too big thus a crap donut gasket seal. And the bolt spacing is jacked up. Only way it bolts to a factory mid pipe is by compromise. Rig it up!!
Invidia RC350 axle back: I dont know.

Dont let the numbers fool you, That 65mm/2.55" Apexi pipe is really 2" due to the step down and the simple fact it fits the factory 17451 gasket. Its all trickry. I'd wager and say the 350 Performance axle back flows real nice...smooth bends and rumor is its made by HKS.