Komo-Tec Manifolds and 63mm Y-downpipe

[Jack]

Has anybody out there installed KT's manifolds/Y-downpipe on their V6....with or without an ECU flash?

Any information on your experiences would be much appreciated.

[GFWilliams]

I have them in my car, the manifolds are part of the 460 kit and the downpipe was to replace my oem one when the flexi broke.  The downpipe doesn’t add any power and is very similar to the OEM one. The manifolds decat the car in the process as the OEM manifolds have they cat in them. Up to you if you want to keep the cat on a race car, but my cat is now after the downpipe in the link pipe section before the backbox.

I have them as part of the 460 kit, quality is good and they’ve lasted a lot of miles now. Of course my car has been mapped to them 

[Jack]

Thanks George.

I have no cats now, no pre-cats in the exhaust manifolds or downstream.  

However, the stock manifolds are quite rudimentary and appear to be restrictive. As for the Y-downpipe, the stock one is 50mm or 2", while KT's track version is 63mm or 2.5"

Photos of the stock pieces off a CupR (not mine) below..... 

 

 

[alias23]

@Jack how are you running with no cats and no ECU remap? Surely its kicking out errors?

[Kristof Thys]

@alias23 Whilst Jack being several hours "behind" us, I can answer how it's done on DixieV6's car, as he runs no cats either.  The only thing to do is get 2 O2 simulators for the post-cat O2 sensors to trick them in thinking there is still a cat/cats present.  Basically you alter the waveform reading of the sensor.

This can be done mechanically (like Dixie did); or can be done electronically (needs some limited electronics in parallel over the sensors).

This is also a solution when you do have a sport cat but due to its placement further down the exhaust stream compared to OEM doesn't heat up quickly enough to avoid the "P04xx" codes (catalyst efficiency below threshold bank 1 or 2).  I know that on some Komotec installations this is done "out of the box" too to avoid the CELs.

sorry for OT.

 

On topic: sry, no clue.  I thought that 57mm aftermarket was already pretty big (most aftermarket versions for the 3xx cars are 54mm) for the Y-pipes until Lotus brought the 60mm version on the 4xx cars. 

 

Edited August 14, 2020 by Kristof Thys

[Jack]

Hi Imran, no codes/errors w/o cats -- that's how the CupR comes from Lotus.

Lotus Motorsports uses a track-only calibration for the CupR ECU.

Adding the KT exhaust manifolds and their increased diameter  (2.5" vs 2" stock) track Y-downpipes will reduce restriction and will add a bit of torque and HP.  Obviously, to maximize the benefit from the manifolds and Y-downpipe, an updated calibration would be needed -- that may happen eventually.  KT indicated that they don't have new maps for the CupR ECU, probably have to go with  a MoTec ECU eventually.

I've been informed that even w/o an ECU re-flash, the car's ECU (which is quite capable) will adjust appropriate tables to handle the increased flow and will make "some" additional TQ and HP, w/o harming the engine or affecting the shifting strategy of the Shitec TCU.  I will be looking at A/F, timing, etc post install, if, and when, I do this.

@Kristof Thys -- Interestingly enough, the stock CupR S-pipe is 2.5", while the Y-downpipe is only 2" OD.

It's my understanding that the Exige 4xx cars uses 3.0" OD downpipes but then drops down to a smaller OD at the S-pipe

 

 

[Seriouslylotus]

Im in the process of a few upgrades on my 3Eleven.

I bought a 400 series Y pipe from Lotus and can tell you the Y pipes that connect to the manifolds are 60mm and after they join at the Y the pipe is 76mm

The Lotus Quiet silencer is also 76mm inlet and outlet

[Kristof Thys]

@Jack Like stated above and confirmed by Dave, the 4xx cars have 60mm Y-piping merging into 76mm going to the S-bend and back box.  It is my understanding that the S-bend on 4xx cars is 76mm.  On the V6 and 350 (and 380) it's 63mm (and the Y-pipe is 51mm).

 

Edit: just measured: the S-pipe/bend on 4xx car is indeed 76mm.  So for 4xx: manifold (51mm?) -> Y-pipe 2x60mm -> 76mm S-bend -> 76mm back box.  For 3xx: manifold 51mm -> 2x51mm Y-pipe -> 63mm S-bend-> 63mm back box

 

Edited August 14, 2020 by Kristof Thys

[Jack]

11 minutes ago, Kristof Thys said:

@Jack Like stated above and confirmed by Dave, the 4xx cars have 60mm Y-piping merging into 76mm going to the S-bend and back box.  It is my understanding that the S-bend on 4xx cars is 76mm.  On the V6 and 350 (and 380) it's 63mm (and the Y-pipe is 51mm, whilst on 4xx it's 57mm).

 

Got it....I think we're saying the same thing?  On my CupR, it's a 51mm Y-pipe merging into a 63mm S-pipe.  Hence my desire to increase the Y-downpipe to 63mm (from 51mm stock) by going with the KT's Y-pipe that will attach to KT's manifolds.  

If I find the data is not good post KT component install, I'll go back to stock and sell the KT stuff. 

@Kristof ThysThanks for your comments

@Seriouslylotus--Dave,  always appreciate your input and any advice would be welcome.

Photo of my current  setup with Burns re-packable 63mm inlet muffler.....  stock S pipe (slightly modified) and stock Y-pipes have been coated....

 

[Jack]

As an aside, since the photo in my previous post was taken, I have gone with a Moroso wet sump in the hope of eliminating some oil pressure drops under heavy braking and some high "G" (1.4-1.5) in certain low speed corners.  I felt the Moroso sump had better baffling than the stock CupR pan. 

Data post install supported my belief.    

Bibs/moderators--- feel free to move, 

Photos for comparison....

[Hangar 111]

The Cup R manifolds and Y-pipe are a bit of a dogs breakfast in my experience.

KT stuff should fit OK.  As for needing a tune, it would be advisable due to the dimensional changes, to take advantage of the improved hardware, but you might get away with it from a fuelling perspective on the R map.

Incidentally, did the Cup R Y-pipe run _very_ close to, or even touch, the Cup sump pan?  Plus side of the Moroso - you don't have to "service" it every 2 years!

Dave

[Jack]

@Hangar111 -- Thanks for your input Dave.

Yes, while the CupR Y-pipe did not touch the stock pan, it was close....might even have picked up a couple of mm's of clearance with the Moroso -- still very close.

Based upon a photo (below) I've seen of the KT track 63mm Y-downpipe and Moroso pan, looks like it will fit OK...fingers crossed.

 

 

Regarding the Lotus recommended servicing of the stock baffled sump's rubber "flaps" ..... never heard of such a thing until reading the CupR Supplementary Manual.  🤨 

That servicing requirement provided me with additional incentive to change out the sump.  Perhaps my "flaps" were in need of service and that explained the oil surge I saw in my data ....who knows?

[Maxi_z]

Hello Jack

I have fitted the Komotec manifolds ( with their y pipe sports catalyzer and ecu remap ) on my exige cup 380 ( that already have oem bigger y pipe and muffler ).

My v6 cup R was already fitted with some upgraded manifolds custom made by team santilli in Italy ( the ones that prepared that yellow and green wide time attack exige cup r ) the tvs1900 non watercooled supercharger and a custom remap of the oem ecu.

With those mods and a conservative remap made for pump gas it was 430 hp ( engine )

I am actually upgrading the cup r to the watercooled SSC tvs 1900 supercharger, forged pistons and conrods, 430 throttle body, etc and even with those upgrades Santilli suggested that the manifolds already fitted ( bigger than oem but not as big as latest aftermarket versions ) would be ok but to upgrade the y center pipe and the rear manifold to latest model sizing so we fitted a 380/430 oem y pipe ( but you can use an aftermarket one from komotec or 2bular ) and a custom rear muffler with bigger pipe sizing similar to yours and then the car should be remapped.

I don t think that you have to get a full motec ecu as some expert tuner could just reamp the oem Lotus ecu ( and the base program was I think well done by Lotus motorsport to work well with the xtrac gearbox etc ) but it would be better to fine tune it for the newer manifolds and exhaust both for performance and engine reliability or at least have some good tuner dyno the car and see the lambda values knock etc.

As you already know all the older v6 have the y pipe and rest of the exhaust smaller compared to the newer models ( there is a nice explanation on the 2bular website ) The aftermarket manifolds that were made for the older v6 were usually not as big as the ones made for the latest versions.

The komotec manifolds are bigger in size and ok to fit even on modded 410 and 430 (and cup r) the fabrication quality seems good and for sure komotec have them usually in stock.

The other choice could be 2bular I think they are even a little bigger and more refined and handmade but usually it takes weeks to order them...

PB racing and Team Santilli in Italy both make custom versions, I don t know the pricing and sizes but if interested I can get some details.

I think that any of those manifolds will be good and it s a good idea to optimize the rest of the exhaust piping to latest size specs