Piper 2.25 fitted, My husband cursed

[m100sandra]

I had my husband fitting the Piper exhaust over the w-e and he really did curse me Its the 2.25 system with the 2nd silencer, Really pleased with it and not much louder then the old standard exhaust, Also the car is much quicker I really cant believe that the Piper can give the little Elan so much more go...... Steve took it out and also commented that it felt fairly fast (His Noble as 430ish bhp so )
I managed to take it out Yesterday and was watching the boost gauge expecting the worst re: Boost creep and but all seemed OK, i think it peeked at 0.8 and then slowly came back down to 0.6 ish, is this normal for it to spike before max revs & then back down? i have a Everast Chip on order.

[dapinky]

Hi Sandra,

Can't comment on the numbers for 2 reasons -

1) The guage isn't terribly accurate - you'd need to run elanscan and see what it is actually boosting at
2) I ported the wastegate when i fitted mine so wouldn't expect to see a 'spike'

That said, it sounds about right for the theory, and i wouldn't worry about it.

Glad you like it though

[texas2201]

I fitted the Peco 2.25 one and it is pretty loud - also fitted the everest chip - but got boost creep so had to have the turbo reamed out from 16mm to 21mm. no more creep - but what a difference - it will put a smile on your face it does to me every time I drive it

got a track day at Cadwell Park on Saturday which I am really looking forward to

[MPx]

I've got the 2.25 piper and switcher chip. Also the Pre cat eliminator and just one sports cat. It does go well, but I too had to have the wastegate ported, though IIRC we stopped at 20mm. No boost creep. Nice and fast, but a bit of a sod come MOT time!

[rip]

It may not be a lot louder at tickover or when cruising but it sounds great when you floor it through a tunnel.
The piper provides less restriction than the standard exhaust so the turbo is able to push in more air with the same pressure & this is where your extra power comes from.
I have the same system as you & my wastegate has not been ported. My boost creeps a little but not enough to cause overboost I don't know why your boost is dropping off at high revs though. The faster your engine is running, the more creep you should get.
You may find that boost does creep to overboost in cold weather when the air is denser.

[dapinky]

Whilst not directly relating to this post, but not quite 'off topic' either.....

.... the sound tester at Castle Combe commented on how quiet the car was when i pulled into the test area. At a steady 4500 rpm it registered 87db.

[tigerdog]

Just a theory regarding the boost drop: is it possible the wastegate is slightly recalcitrant, opening slowly? If yes, then pressure could possibly spike while the gate is partially open, then drop back to more normal numbers once the gate fully opens and the pressure is relieved. Better minds than mind can feel free to shoot holes in this.

[pjw12]

Sandra,

Got the same system on mine and covered 2500 miles with it including Le Mans and back, Sounds perfect, not too loud like my old peco,not too much popping. Infact alot of people comment on how good it sounds, not a bad compliment considering the company it was keeping in our campsite

Only had overboost once so far, going to port when the front pipes are available. With the peco it was a weekly occurance.

[m100sandra]

Ive just had the Evereast chip fitted today(ny son fittd it) and the boost is holding steady, behaving diferent to when just the Piper was fitted? as the 1st post the boost would go up and then fall off, now its around 0.8 on the standard gauge, my son put a seperate boost gauge in just to check what boost that was showing in psi which was around 12-13 psi which is just over 0.8 bar so ive been told, but the boost is holding steady, from around 4000 rpm its straight there and will hold it steady to the redline, But im still loosing a couple of psi any thoughts? or are all cars diferent re: the Everast chip & what boost i should have? maybe having the 2nd silencer on the Piper will hold back the boost a bit?
Any thoughts appreciated.............

Thanks

P.S. He had to adjust the CO pot as the idle was a bit lumpy (im guessing the 9930 chip should have been a 9029? No bearing on the above

[rip]

14.5 psi = 1 bar
12 psi = 0.82 bar
13 psi = 0.90 bar
Target boost for an Everest is 0.9 bar so 13 psi is what I would expect.

A restrictive exhaust will not reduce boost pressure. It will reduce exhaust flow, which is why a larger exhaust allows the engine to produce more power.
If you've not seen it, you may find Enright's boost thread amusing & informative.

[m100sandra]

I was just thinking that the two silencers on the piper might give a slight restriction on boost as it maybe does with a cat?


A3: If you have a stock exhaust system complete with catalysts then you probably won't achieve 0.9bar for much, or sometimes any, of the rev range. If you want to achieve the full boost you can replace the exhaust system with a larger bore item (catalyst equipped ones won't creep either) or some people knock out either the pre-cat or main cat (naturally I can't condone such behaviour). If you stick with a standard system then a Kili wouldn't deliver much less power than the Everest but having the latter won't do any harm and would maximise what you have available.

[Karl Martin]

I have the 2.5” twin silenced Piper. The ‘silencers’, both at the front and rear, wrap around the outside of the pipe and do not change the internal diameter at all. (known as a ‘straight through’ silencer)

Other silencers work by the pipe entering the silencer at one point and exiting at another, the gases going through a series of chambers to absorb the speed of the gas (hence the restriction) and noise.

Info:

“Some stock mufflers have up to 18 psi of power-robbing backpressure. A well-designed performance exhaust typically has about 2 to 6 psi of backpressure. For comparison sake, an unmuffled straight pipe usually has 1 to 3 psi of backpressure.
To get the least amount of backpressure, most of the good, high-performance mufflers available today have what is called a straight-through design. These type of mufflers quiet the exhaust by the absorption of high frequency vibrations in a heat-resistant packing usually consisting of stainless steel mesh and heat-resistant ceramic fibers. They typically have a straight inner core with no baffling at all, much like a straight pipe with many small holes. The pipe is louvered or perforated when it passes inside the muffler's shell, allowing sound energy to pass through the holes but leaving the exhaust gas flow unimpeded. You can see straight through these types of mufflers. The louvered or perforated core is usually wrapped with either Fiberglas wadding, hence the old-school term Glass-Pack or on the better mufflers, stainless steel mesh to help further absorb the sound. On straight-through mufflers, the longer the muffler, the quieter it is. The length usually has no effect on the backpressure, just the noise output. These mufflers work in the same manner as the silencers used on guns. If a silencer impeded bullet travel, you would definitely have problems!”

[surfboardfiller]

The Elan is designed to boost high for a few seconds and then drop, this is normal it is called 'overboost' and works exactly as you described in your first post.

The piper exhaust will not change the turbo boost, that is controlled electronically by the ECU. The exhaust should give you more power but the boost is not a gauge of power just a gauge of pressure in the plenum (when its working properly).

The Everest chip changes the boost, that's when boost creep sometimes happens.

[m100sandra]

I had a drive out tonight with my daughter in her stage 3 VX220 Turbo, running fine, untill i parked up for a chat with her Hood down and the heater on full and a horrible burning smell coming from the heater vents, Not that i would know what to look for i poped the bonnet and all seemed OK, all the gauges reading OK, So we decided to carry on, i was getting worried that it was me red lining it to stay in front of the VX, i ended up stopping a few times to check it over, the smell was still there but not as bad and by the time i had got home it had almost gone, anyway to cut a long story short i mentioned it to my other half he had a quick look then clicked that it was maybe the exhaust wrap he had put on the front section of the exhaust without telling me so its fingers crossed thats what the smell was, ill have to keep the revs down a bit in the future
Sandra

P.S. the daugter was shocked how fast the Elan went.......