Piper Exhausts turbo downpipe development thread

[HJ2]

Toll !

[bobbrown]

maybe the changes we are making need different timing settings.

I assume the base timing was correct as you mentioned on another thread that GST set it, I do not think there should be any need to move the base timing, if you advance it and knock occurs then the ecu will just retard it.

As far as the exhaust is concerned I still do not see how the down pipe is going to be evaluated as you had the whole exhaust changed, we all know the exhaust system reduces back pressure and therefore improves performance on it's own.
Trying to work out what changes the exhaust makes and what contribution the down pipe has made is going to be impossible with out taking a step backwards and testing with just the exhaust and then with the new down pipe. Testing on the road is going to be very subjective and even comparing one car to another is likley to introduce errors as no two engines are likley to produce the same HP

Bob

[stevo]

hello everybody peeps, been a while since i was on here and just found this thread. the original stiffy was just a pet project while my 2.5 exhaust was being made (by custom stainless, hillington) back around 2005. the idea was to shape it so it had the shortest fastest least restricted flow and for it to run with either a 2.25 or 2.5 exhaust joined by a short flexy under the sump. there was no flow testing i just ran it in my car with a 220mm ported wastegate and an everest chip. that plus a cone filter and mildly worked head made for 241bhp on ava's dyno. i was well chuffed and after some prompting i made 10 more for sale and as far as i know i had 10 happy customers

[ashm]

Hi all,
Not been around much recently - any news on the downpipe front? It'd be great to get the Elan all snazzed up in time for summer!
Ad

[HJ2]

Same here!

I wish it was in my garage just now whilst the head is off 'n all...
One serious interested potential customer waiting ...

[PiperRS]

Hello all!!

Sorry for lack of updates! The first batch is nearly finished, I will soon have a handfull of downpipes ready for sale, if anyone wants a ceramic coated version they will have to wait a few more weeks, but the rest can start placing orders soon!

Il keep you all updated!


Kind regards
Tom Edmunds
Piper Cams and Exhausts

[rip]

I'll be interested to see some pics of the finished product when available.

[PiperRS]

I'll be interested to see some pics of the finished product when available.

Yes Il have pics of the finished downpipe and the fitting kit included, Il post these ASAP.

[tb10]

What costs are we talking delivered as I'm putting my S2 back on the road soon and I have the Piper SS exhaust ready so a down pipe will be just great.

regards



John

[m100sandra]

Any further news with the downpipe, Hopfully ill be trying to talk the other half into removing the Turbo soon to port the wastegate

[cliff]

I think that this thread hasn't gone the way that most people wanted. There has been a lot of discussion, argument, differing opinions and very technical, sometimes bloody minded points of view.

My car was the guinea pig for this downpipe, and as I said initially, I was very happy with it. Looks great, sounds fantastic and as it was off recently, I have had it ceramic coated. As I also said, I was getting overboost, I do not see the point of being a test subject without being brutally honest about things.

My car has been off the road for a while so after quite a lot of work, samco hoses, new radiator etc, turbo now has been ported & I have fitted an Everest chip & lambda sensor.

viewtopic.php?f=80&t=19040

The plan was uprate the brakes but for some reason, I do not seem to be getting any communication about that! Standard, well maintained brakes with greenstuff are just about adequate.

The Alfa clutch failed yesterday, a slave cylinder is on order but having absolutely no faith in the totally incompetant German spare parts system, had to use the Elan today.

As I have written before, the car feels more responsive. There is a great road between my village and the next so opened the throttle in 2nd & 3rd. Acceleration up to 6500rpm was rapid, boost up to .9 & no overboost! Just to be sure, I had another go with the laptop in the footwell on another road, again no overboost. If someone tells me how, happy to post the elanscan.

When the brakes are uprated I will give another update. Porting the wastegate seems to be the way to go. Did I mention, it sounds fantastic

[HJ2]

How about that update now!

[cliff]

I'd really like to, but:

CIMG1340.jpg

There are a few things missing at the moment.

Seems like I am going through the phase where everything I touch needs replacing. Can't last for ever can it?

[HJ2]

I hope not!
But we all have our own problems

[ccb056]

Excited to see how this goes.
I'm primarily concerned with replacing the original rusted exhaust with a 2.5" stainless all the way to the turbo to reduce the turbo lag, not necessarily running higher than stock boost.

Other than cliff's test, have any other tests been run on a car with stock ECM, and OEM or 2.5" exhaust?
Skimming over the previous pages and some other threads it appears that porting the wastegate is necessary, conventional wisdom has been 20mm but I've read some going to 21mm.
Any more data on the proper wastegate diameter?

[surfboardfiller]

Excited to see how this goes.
I'm primarily concerned with replacing the original rusted exhaust with a 2.5" stainless all the way to the turbo to reduce the turbo lag, not necessarily running higher than stock boost.

Other than cliff's test, have any other tests been run on a car with stock ECM, and OEM or 2.5" exhaust?
Skimming over the previous pages and some other threads it appears that porting the wastegate is necessary, conventional wisdom has been 20mm but I've read some going to 21mm.
Any more data on the proper wastegate diameter?

I think that's mainly with an ECM Chip added which gives more boost. Most people tend to 'see how it goes' with the upgrade and port if necessary. Although some just like to tinker the general feeling is if you up the boost pressure then porting will help. I'm sure Geoff will confirm/correct me on that though. My car sounds superb now it's running.

[whippit]

When i ordered a 2 1-4" from piper they sent me a 2-5" by mistake, i was on a standard ecu and got over boost , i did fit a PCE at the same time though,
i carried on using the car as i could balance the throttle and over boost, huge power increase
i only ported the wastegate after i head butted the steering wheel after chasing my mate on his aprilia,
i opened the gate to 21mm without any problems

[HJ2]

When my stock pipe gave up, I switched to 2.25"
Result: Boostcreep. Porting fixed it, so:

But now we're talking exhausts, not downpipes

[ccb056]

When i ordered a 2 1-4" from piper they sent me a 2-5" by mistake, i was on a standard ecu and got over boost , i did fit a PCE at the same time though,
i carried on using the car as i could balance the throttle and over boost, huge power increase
i only ported the wastegate after i head butted the steering wheel after chasing my mate on his aprilia,
i opened the gate to 21mm without any problems

When my stock pipe gave up, I switched to 2.25"
Result: Boostcreep. Porting fixed it, so:

But now we're talking exhausts, not downpipes

It looks like there is boostcreep with the big bore exhuasts and stock ECM.
In the case of a PCE the wastegate had to be ported to 21 mm.
With the new downpipe I would assume the dP across the turbo would be even greater (otherwise why else buy the downpipe), possibly requiring an even larger port of the wastegate to eliminate the creep.

The wastegate can only be ported so large, my concern is this new downpipe would create a dP large enough that even the largest possible port on the wastegate could not eliminate boost creep for the stock ECM.
This is why I'd like to see more tests.

[surfboardfiller]

Make sure your waste gate is free and not seized, limited by muck/corrosion or sticky as this can give over boost on standard cars and is certainly not going to help tuned cars.
I had the waste gate ported while the turbo was being rebuilt and I have changed the boost controller on my car so the results will not be so helpful to you all.