PiperRS 2.25" or 2.5" Exhaust for all M100s

[chris.t]

dave, do me a favour please don't alter the quotes cos it really does cock the continuity of the thread up.

[Monty]

While that's a little higher than I might have expected, do you know what distance the test was taken from and at what RPM the peak noise occurred?

In theory, both could could make a significant difference to the reading couldn't they?

The microphone was about an inch or 2 from the tail pipe and the revs were at 3/4 of redline which is standard practice for a static noise test. The car was well warmed up as well, don't get noise tests done on cold cars they will be noisier as well as the fact you are revving the engine quite hard. Also when doing the test build up the revs slowly, this will avoid over revving and extra noise.

Thats not correct

From MSV website for Oulton Part

Noise checks to establish adherence to the relevant limit will be conducted in accordance with current measuring methods as defined by the MSA. Essentially this means that the noise test shall be measured from a position 0.5m behind the exhaust at a 45 degree angle, with the engine running at ¾ maximum revs.

M100 Turbo is rev limit is 7k, so 3/4 is 5250 rpm

[chris.t]

While that's a little higher than I might have expected, do you know what distance the test was taken from and at what RPM the peak noise occurred?

In theory, both could could make a significant difference to the reading couldn't they?

The microphone was about an inch or 2 from the tail pipe and the revs were at 3/4 of redline which is standard practice for a static noise test. The car was well warmed up as well, don't get noise tests done on cold cars they will be noisier as well as the fact you are revving the engine quite hard. Also when doing the test build up the revs slowly, this will avoid over revving and extra noise.

Thats not correct

From MSV website for Oulton Part

Noise checks to establish adherence to the relevant limit will be conducted in accordance with current measuring methods as defined by the MSA. Essentially this means that the noise test shall be measured from a position 0.5m behind the exhaust at a 45 degree angle, with the engine running at ¾ maximum revs.

I can only say that my statement was based on how they were actually testing cars when ever i've been to Goodwood or Bedford. If that is not standard then i apologise. I have known cars to be louder on the static and quieter on the driveby and vice versa. I remember a Nissan Skyline at Goodwood had a static reading of 85dB and on the driveby it well exceeded the 98 limit and his day lasted 2 sessions, one black flag and then he was out. I went to Goodwood and asked them to do a static on my car just for reference and the increase with the piper was 8dB. As i said I have a track day in May at Goodwood so will I have a driveby of 104dB which will exceed the limit by 6dB, well i hope not Monty whats the ruling at OP about drivebys?
M100 Turbo is rev limit is 7k, so 3/4 is 5250 rpm

[PiperRS]

Hey Garry, I see you're on VX220.org. I told the guys on there about the Piper i have on the Elan and how pleased i am with it. They're very noise conscious on there cos they sometimes have problems on track days. I've got a Miltek on my VX now but would have had a piper if i had known!

Yes i see you had posted on their singing our praises, thank you for the support Shame you have a Milltek on the VX tho

The microphone was about an inch or 2 from the tail pipe and the revs were at 3/4 of redline which is standard practice for a static noise test. The car was well warmed up as well, don't get noise tests done on cold cars they will be noisier as well as the fact you are revving the engine quite hard. Also when doing the test build up the revs slowly, this will avoid over revving and extra noise.

Most tracks say that the static test is to be taken half a metre from the tailpipes at a 45 degree angle. The commonly accepted limit is 98 - 101 db but it does vary from track to track

I hope this helps.

[Monty]

Chris,

I`ve started a new thread in the trackday section on trackday noise levels, the 1st post is Bedford and has how they measure static & drive-by

viewtopic.php?f=72&t=14274

[Specky]

Well eventually I've fitted the 2.5 Piper...

I'm doing it in stages just to see what the differences are....

So 2.5 Piper withouth second silencer... standard pre cat,waste gate and ECU, no BOV

At Idle...

The noise is a little louder and deeper than standard, but not a loud as a PECO...

She has a nice little burble at idle and when the accelerator is Blipped.. two or three little pup's...(Not Quite little pops)

Fully floored.... 0.5 Boost, no over boost

The differences...

The engine seems to run smoother and the exhaust is little louder...Oh and the escaping waste gate gases seem a little louder, but that's about it..

As for acceleration... I didn't notice a difference...

As for fitment...It took just over the hour and the fitter said is was a B******D...

The exhaust sits very slighty over to the left... (and I'm being picky)

So overall I'm happy little puppy

TTFN

[chris.t]

Well I know my 2.25" was tight so not surprised your fitter struggled a bit but at the end of the day its fitted. I have noticed improved performance though so I'm a little surprised that you haven't. Mind you I'm also convinced that my fuel economy has increased but I guess that could be due to other factors. We'll have to compare 'pups' when i see you next

[rip]

I have roughly the same feedback as Chris. Power is up with/without boost. Boost creep now exists (which I can control to avoid overboost).
I have the 2¼" with the second silencer. I have now driven it roof-down so have a proper comparison. It is not really louder than stock but sounds a nicer, deeper tone. Overrun pops are rare but I have heard one.
Spud took my Elan out for a short drive the other day & came back with a big grin on his face saying he would get a Piper for Custard

[abmunro]

Had my 2.5" exhaust fitted today...

It has the pre silencer in. It's only a little louder than standard but does have a lovely sound. ( Great for track days )

Extremely well engineered. Missing all the bits and bobs by only a few mm's. Missing being the operative word. It is held in perfectly.

Very Happy.


Fitted By Colin @ REVLINE in Whitley Bay. ( Our Local Lotus Independent Garage )

Cheers

Tony

[Specky]

Update...

Took the old girl out today..... and I do have Boost creep and over boost......

At first she Boosts to 0.5 Bar, but then it slowly builds whilst pedal full floored.... and 0.8 Bar-ish...woahhh... fuel cut off.... CEL etc...

The last bit happened in the blink of an eye... I watching the Revs for the gearchange when she cut out and it occured before I wanted to change gear...

Sadly the car isn't useable for quick driving or the track... but hey hoe, what did we exspect...

I'll update after the next two mods are done..In a few months

TTFN

[Specky]

More of an update...

Near enough a permanent code 31..

Which limits the car to 4000 revs

So dare I say it... She's slower with a Piper

Must do the Mods very soon cos she's pantz

TTFN

[max and andy]

2.25 or 2.5 .How do people choose? Why do people think id better get a 2.5 ? Andy

[tigerdog]

the bigger the pipe, the more exhaust it will flow all other things being equal. The stock exhaust seems well matched to the stock power profile. My car has a 2.5 because the previous owner was aiming for Costas-like power output. I guess it really depends on how far you plan to go with engin modifications. If you're aiming for 275-300 horsepower, 2.5 seems like the choice. If you plan to get rid of your precat and fit a mountain chip, others here seem to have found 2.25 a good match. 1/4 inch doesn't sound like much, but having just had Smaug back from the exhaust shop for the 3rd time in 3 days to fix a buzz where the 2.5 crosses over the prongeron, I think an extra bit of clearance would be nice; it would help avoid such fiddling down the road. I guess it depends on your tolerance for ongoing fettling. For me, knowing that with the exhaust and his other extensive mods, Smaug can boost to 1.1+ BAR is fun enough to be worth the hassle.

[nitroman]

the bigger the pipe, the more exhaust it will flow all other things being equal. The stock exhaust seems well matched to the stock power profile. My car has a 2.5 because the previous owner was aiming for Costas-like power output. I guess it really depends on how far you plan to go with engin modifications. If you're aiming for 275-300 horsepower, 2.5 seems like the choice. If you plan to get rid of your precat and fit a mountain chip, others here seem to have found 2.25 a good match. 1/4 inch doesn't sound like much, but having just had Smaug back from the exhaust shop for the 3rd time in 3 days to fix a buzz where the 2.5 crosses over the prongeron, I think an extra bit of clearance would be nice; it would help avoid such fiddling down the road. I guess it depends on your tolerance for ongoing fettling. For me, knowing that with the exhaust and his other extensive mods, Smaug can boost to 1.1+ BAR is fun enough to be worth the hassle.

Tiger, here is your PERMANENT fix for that, I did it on my first red Elan:
Put car on ramps.
Use jack to raise exhaust so you have clearance between it and the subframe.
Clean subframe under exhaust.
Squeeze out clear silicone (the gasket-maker kind) under the exhaust.
Lower exhaust SLIGHTLY into the silicone.
Allow to dry overnight.
Remove all gravity-defying implements & drive buzz free.

[max and andy]

I'm going to upgrade to a 2.25 exhaust.I believe that i would be better getting rid of the pre cat rather than the main cat.The pre cat being the most restrictive.Would you risk not fitting a sports cat.My car has just over 30000 miles.Do you think i would have a problem with emissions? going without.Are there many who risk going without ?Or do most go down the sports cat route.I would be interested in anyone who runs without .Please advise. Andy & Max

[GeoffSmith]

Completely cat free S2 with 2¼" Peco - no MoT emission problems.

[max and andy]

So you reckon i should go for it without ?Have you got a PCE fitted or did you sort out your old pre cat ?I think Ive read about something you can adjust pre MOT ? To help bring the emissions down. Max & Andy

[GeoffSmith]

I don't think we should advise you what to do - only you can decide on the risk you take and (probably most importantly in these troubled times) whether you can afford the time/money to rectify the situation if it all goes tits up.

Anyway, both of my cats had 'lost' their innards before I bought it (although I only found out when I fitted the Peco and ported the wastegate) and had presumably passed many MoT tests without as well as the four or so since I bought it. I have one of Nitro's PCEs to go on sometime but it's still the OEM cast iron monster at the moment. I think you're referring to the oft-quoted pre-MoT advice to have the car warm so the emissions will be minimised, however the test requires the car to be at normal operating temperature so any decent garage will do this for you and wait until the readings are low enough if necessary. The S2 is a closed loop system (O2 sensor tells the ECU if the exhaust is rich or lean) so you cannot adjust anything but you should make sure the base timing is set correctly and all sensors are in good order.

[nitroman]

After Renault left the USA market and was just supplying rebadged cars for AMC, the government found out years later that all the Renault cats from 1987 to 1988 had no innards. Cats were more expensive then than now and Renault saved well over $100 on each car by not having to buy the platinum. Renault had no assets in the USA, so the US government could not take any punitive action.

The stranger thing is that the 1987 Renault I had always passed the yearly tests I took it too! I took the exhaust apart at the flange behind the cat & verified that there was nothing inside.

[max and andy]

I just wanted the views of a few people who had done it before i decided.Nitros Oem Is his home made PCE .Is that right? Going to work ,so no time to check back in the for ems. Andy