PiperRS 2.25" or 2.5" Exhaust for all M100s

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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby rip » Sat 10.04.2010, 00:07

The switcher should have no effect on off-boost settings. AFAIK it only modifies boost targets & mixture settings when on boost. When off boost, your ECU should switch back to closed-loop mode & adjust mixture according to the lambda sensor values.

My exhaust was REALLY sooty when the timing was set by the book. It spluttered to life, economy was down, overrun was very common, overboost occurred at 4100rpm & boost gave me very little extra performance.
After a bit of trial & error with ignition timing, I improved all these without introducing knock. I then got the timing light out & found it was 32 btdc. I still don't understand why & won't begin to pretend that there is not something odd about my engine.
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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby Breed » Sat 07.08.2010, 13:03

Just passed my 2nd emission test with a piper 2.1/4 system with no main cat, pre cat still in place car 1996 S2. Do not know if there is anything in the pre cat but would think there is as no boost problems. It was done as a basic emission test and was done at Simply Auto's chain.
Fast idle test = pass
Engine speed not checked
CO level 0.5%. Pass is 0.20
HC level 22 ppm. Pass is 200
Lambda 1.02. Pass is 97 to 1.03

Natural idle test pass
Engine speed not checked
Co level 0.00% Pass is 0.30

Results same as last year except Lambda is .01 higher.

Car did not pass MOT due to little or no effect on rear brakes. Doing the sliders but drivers side looks O/K. Have a feeling it may now be something else as both sides have the same problem
according to the fail sheet

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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby surfboardfiller » Tue 08.03.2011, 21:16

Anyone interested in a prperly developed Piper Turbo down pipe?

I'm tentatively looking at a group buy if anyone else would like to join in this topic: viewtopic.php?f=85&t=18813
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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby yilmazmotorsport » Wed 25.02.2015, 15:13


I was wondering about Piper 2.25 to my stock M100 turbo, I have question to you guys, what kind of performance-improvement can I expect after fitting 2.25 system without cat and pre cat ?

And second question according to your experience with exhausts to Elan, I do like some bass-sound from under car, but if it will be loud ?

Thanks for any answer & rgds,
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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby Enright » Sat 28.02.2015, 22:25

A performance system can provide a lot more power than expected because it can provoke boost creep, which ultimately leads to overboost and fuel cut. The cure is porting the wastegate, but it's not a quick job. Well actually the job itself IS quick, but getting to it is a pain (just like changing the cylinder head gasket).
The key thing I guess is that it opens up the options for big power gains when combined with a freer-flowing air filter, dump valve (whether you go for recirculating or open is down to personal preference), and possibly a chip. You should easily be able to get around 205bhp with that little lot.
Striking fear into the hearts of duplicate posts everywhere...! :P

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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby HJ2 » Sat 28.02.2015, 23:22

Hi Kamil,

In my experience with a healthy car:
Going to an 2.25" exhaust will bring you 8 HP (dyno-ed)
Emptying the pre cat as well, together with no main cat, another 10 or so ( not dyno-ed)
Having a bigger exhaust enhances chance of boost creep. I had it on my car after exhaust upgrade and empty pre-cat, without main cat.
More important than HP gain is the fact that your turbo will spool-up faster!
I'll give a longer reply tomorrow, this iphone keyboard is crap! :-)
If you always do what you always did, you always get what you always got
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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby epipete » Sat 28.02.2015, 23:29

I'm running stock but with a 2.25 SS exhaust, I havent needed to port the turbo (though others have) but there is an overall improvement in performance.

As to sound: it is loud, such that I can't leave the car idling on the drive for fear of provoking the neighbours ire (which is a pain when your trying to test your fans), but it won't sound like a Ferrari. Occasionally it pops when I change gear - which, childishly, I try to achieve whenever I pass the local school.

Overall though, I think it's an improvement.
You know more than you think you know, just as you know less than you want to know. ... Oscar Wilde
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Re: PiperRS 2.25" or 2.5" Exhaust for all M100s

Postby Simon_P » Sun 01.03.2015, 00:07

Hi Kamil,

Piper developed several options depending on what you need.

I have a standard S2, which has a per-cat and a main cat. I bought the Piper configuration with a sports cat to replace the main cat. It is the best money I have spent. Well made, easy to fit, no boost creep, better sound.

It is quite civilised, not too loud, ok on long journeys - I think it would be louder if I did not have the CAT, but Piper offered an additional silencer in its place if you don't want it too loud, but don't want the cat.
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