Which Exhaust

[nhaynes]

So I'm looking for a bit of help from experienced members please! My original Lotus SE Turbo (non cat) exhaust has finally developed a couple of blow holes just before and after the back box joint so I think the logical way forward is a new system from the 3 bolt flange on the down pipe. I've read many of the posts already on the forum (thanks to all that have contributed). My Elan is still mostly on original equipment and I'm always torn between keeping it original or upgrading. I'm looking at two 2.25" twin silencer systems from a) Piper and b) PNM. I'd appreciate your comments on which you think is the better system. I see that Piper has worked with us to develop a new downpipe from the turbo and I'd like to support Piper if they're proactive to our needs. I think Piper also offer 10% discount (always a plus but not a deal breaker for PNM). As I've not upgraded performance and I don't take my Elan on the track, I don't feel the need to upgrade to a 2.5" dia system, I think I'd prefer the clearance to the underframe. I'd also prefer a quiet ride so think the twin silencer system is for me. I'm assuming that both after market exhaust systems have re-routed slightly with a revised flex joint to enable a 2.25" or 2.5" pipe to fit between the body and underframe without the need for a crushed and flared section as on the original. Has anyone experienced any issues with this re-routing?
Anyway to summarise, here are my questions:
1. Piper, PNM or other?
2. 2.25" or 2.5"?
3. Twin or single silencer?
Many thanks,
Neil.

[dapinky]

Well,

I have a Piper single box system, and it sounds about the same as Ripo's 2-box system when we first fitted them....

It always passes 'noise testing' at Castle Combe and other circuits, so no issues there.

2 1/4 is enough for me.

PNM is a rebranded 'Cybox' system, which is the newer name for 'Peco'...... so it has a good pedigree.

I am relly happy with Piper, but others are happy with what they have as well, so no great help I'm afraid.

[Simon_P]

Just my thought and the sound it makes is a matter of personal taste.
1. Piper - Same routing same hanging points and nicely made.
2. Definitely 2.25 the tight bits are even tighter with 2.5 and there is inevitably less clearance by the sump - you will hit it anyway.
3. Twin if you want quieter. The piper system is the quieter of all the systems I have heard but still noisier than the the original. You'll like the note and it is quiet enough. I have a cat but I expect that the additional silencer will have similar effect - They may make it to order in which case you could ask if there is anything they can do to make it quieter.
Piper worked with LEC to develop the whole system which is why there are so many options and probably why it is so good. The best money I have spent on my car.

[RonR]

If your front sections are OK and you just need a new standard mild steel back box I fitted one last year - Kelvedon have them for a good price Here, mated to a stainless mid section from SJs Here Fitted because of WAF (Wife Acceptance Factor) - It's certainly quieter that the PNM/Peco/Cybox I had on before.
No connection to either supplier - it's what was available at the time.

[MPx]

Like others, I have experience of only one of the options...but I do like it.

Piper, 2.25, single silencer plus sports cat.

[Rambo]

I have experience of 3 systems, starting with the original PECO system, and was 3rd in line after GeoffS and Monty. I also have the PNM Cybox, which, as already alluded to, is the PECO in disguise

I also have the Piper exhaust on my NMY. All 3 are full SS systems and all 3 have been recommended by me in the past. As PECO is no longer available it's either Piper or Cybox for me.

And I would go with the full Piper 2.25" system every time

Go with Piper Nick, you won't regret it. And your M100 will sound like a proper sports car

PS I've never ported the wastegate and never had overboost problems. I've only ever gone with the 1 silencer too as I quite like loud

[Steve A]

Hi Neil,

Before you get too carried away, have you ported the waste gate on your turbo ?
If the answer is no, then you will almost certainly suffer from over boost on your first attempt when giving it some stick
There's plenty of this subject for you to read on this very forum.
I bought a Piper last June and got 10% off.

[Steve A]

PS I've never ported the wastegate and never had overboost problems. I've only ever gone with the 1 silencer too as I quite like loud

That might be because I also have the Piper down pipe ?

[nhaynes]

Thanks for all your excellent replies. I'll probably surprise you all in what I'm about to say....
Like I said, I have an original spec Elan SE Turbo and I always wonder whether to upgrade or keep original. I know the Piper or PNM systems will give better performance and may require re-porting the turbo wastegate if I get turbo over-boost which is within my capability. However, I think keeping to the original spec is strangely more appealing. I spoke to Steve at SJ Sportscars yesterday and he does a full stainless 2mm dia with the squished section over the underplate so I think I'm going to go for that. This way I will maintain the original condition of the car as best I can.
Would appreciate any comments.

[MPx]

Your car, your way....end of.

Looking at other models/marques its likely that a totally original car will eventually become more valuable than a modified one, even if the modifications are "club approved", well judged and in keeping. Having said that, its a moot point to me whether an after market stainless exhaust in the right size is any more "original" than an after market stainless exhaust slightly larger. But I've no idea how the market judges that or other NLS parts. I've done all of the common mods to mine and its a much better car to drive, but its clearly not all original.

[Rambo]

Yes, it's your car so....

Personally, I like the sound of the Piper/Cybox/ Peco. It makes the M100 sound properly sporty rather than sound like an MG or an MX5

[Simon_P]

A stainless steel exhaust isn't original.

You'll also find that stainless steel produces a different sound and is louder - This is why the extra silencer may be beneficial and why the more expensive ones are more expensive.

If you want to keep it original then just buy a new back box - Only £90 quid from a lotus dealer.

I don't get boost creep with with my Green S2 which is standard except for the piper system (with cat). The Piper system doesn't have a flattened section and is sufficiently well made that it has no clearance issues.

[nicowalker1]

I have the 2.25 pecco. Sounds fab when enjoying twisty B roads but drives me mad on a long run. I also find it a tad embarrassing when driving in busy town centres.
I’m hoping to get a piper with additional silencer next time.

[rip]

Well,

I have a Piper single box system, and it sounds about the same as Ripo's 2-box system when we first fitted them....

I'll second that.

We put them side by side at Castle Combe a few years ago. The difference was so slight that it could easily have been us convincing ourselves that they were different because we knew one had the extra silencer. I felt a little disappointed to not hear a difference after having paid extra for the 2nd box.
They were idling & I think got revved up a little. It would have been difficult to compare them side by side on track when there may have been a difference.

There may be a difference when cruising at 70 (like some Peco owners describe of theirs). Mine does not sound at all boomy at this speed. I am sure if Dave's did, he would have mentioned it...but he hasn't.

[nhaynes]

So, I ended up purchasing a Stainless Steel exhaust from SJ Sportcars as this is the closest I could source to the original Lotus specification. I bought the Front Section (SJ100S0004), the Centre Section (SJ100S0003) and Standard Rear Silencer (SJ100S0002). I didn't need the downpipe from the turbo as it's stainless steel and is still in good condition. I also purchased 5 new rubber hangers (SJ100S0001), 2 new joint clamps (A100S6011F)and new hardware for the spherical joint at the end of the downpipe: 1 Cone Seal (A100S6005F), 2 M10 Studs (A100S0030F0), 2 Springs (A100S0032F), 2 Spring Washers (A100S0031F) and 4 M10 Kaylock nuts (SJ089W0001).
Now bearing in mind the original mild steel exhaust was still on my Elan, an angle grinder was an essential tool as those exhaust joints were never coming apart. I have a pair of low approach ramps so I had to do front and rear ends separately. It's worth removing the bottom rear screws from the right rear wheel arch liner so you can get better access to the rear silencer bracket that wraps around the silencer case. You can also drop the entire mount from inside the boot if you prefer. I used the angle grinder to cut through the joint just ahead of the rear silencer joint. This was actually a mistake as I'd have been better cutting just behind the joint. The rear silencer unit seems to have been designed to just about slip out between the rear wishbones and suspension turret. So the slightly longer length I'd left meant I couldn't remove the rear silencer and had to make another cut behind the joint. Once off I backed the car off the ramps (sounding like a tractor now) and then raised on the ramps this time from the front, split the spherical joint at the end of the downpipe and removed the front and centre sections. Remember to remove the cone seal from the downpipe as it's easy to miss.
Ahead of fitting the new sections, I ensured all the sliding joints were free to slide. It's really worth opening these joints up a little bit as it's so much easier to fit when the joints are loose. They'll close up again nicely when they're clamped and I used jointing paste to ensure no exhaust gas leaks. My front section also required a little bit more metal bashing to provide adequate (10mm) clearance to the steering rack. It's worth checking all the sections are clear of chassis, steering and any other adjacent components.
Putting the new sections on was pretty straightforward, I used a couple of sockets; one 1/4" socket set small enough to get in at the front of the spherical joint and a 3/8 socket set with extender bar to get at the rear from the rear of the underplate. Getting the rubber mounts onto the hangers is tricky and requires a fair bit of strength. It's worth soaking the mounts in diluted washing-up liquid which helps them slide onto the hangers better.
Once the new front section was fitted, I switched the ramps to the rear and fitted the centre section and rear silencer, all pretty straight forward.
I'm pleased with the end result (see attached photo). The exhaust fits really well, tail pipe is centre to the rear bumper and all the other sections fit well (though as said earlier I did have to modify the front section for better clearance to the steering rack). The exhaust note is really nice, sounds sporty without being embarrassing noisy. I've not tried in on the motorway yet to see if there's any booms but I'm expecting it to be fine.
So, it's a thumbs up from me for SJS's system, if you want a stainless exhaust that replicates the original as close as possible.