Piper Exhaust Down Pipe

[GeoffSmith]

... and no separation of the wastegate pipe.

I am not convinced by the separate pipe, looks wrong to me.

Sorry Phil, bur Stevo's stiffy looks wrong to me. If they're not split adequately, turbulance will affect the ability to control the boost - take a look here at the bit after 4:05.

[dapinky]

We are looking at 2 possible products:
NOC: To fit cars with NO Cat or eliminator (S2 completely de cat or SE).
PCE: To fit cars with a piper Pre Cat Eliminator.

1. NOC - Phil (surfboardfiller)
2. NOC - Phil (surfboardfiller)
3. NOC - Steve A, depending on results and price for an SE
4. PCE - esprit888 (LHD FED car)
5. PCE - Pinky
6.

[rip]

We are looking at 2 possible products:
NOC: To fit cars with NO Cat or eliminator (S2 completely de cat or SE).
PCE: To fit cars with a piper Pre Cat Eliminator.

1. NOC - Phil (surfboardfiller)
2. NOC - Phil (surfboardfiller)
3. NOC - Steve A, depending on results and price for an SE
4. PCE - esprit888 (LHD FED car)
5. PCE - Pinky
6. NOC - rip
7.

[dapinky]

Phil,

I'm not trying to hijack the group-buy thread with a discussion on the item (I can do it without trying, being a BOLLECKS member ).....

....to fit a new downpipe to the existing Piper PCE may be counter-productive, as the PCE is basically just a funnel - as such, would we not just be creating more problems by opening the flow out, just to squash it up again?? (or am I missing something obvious??).

Would flow be better to go from wastegate housing straight to the piper exhaust, and just remove the PCE (ie as per the original idea).

Whilst i have obviously spent money on the PCE (which gave a good improvement), i would prefer to get something worthwhile from this project and end up removing it if necessary, as opposed to getting a half-improvement by keeping it and upsetting the flow.

Just a thought........

(in which case - anyone wanna buy a Piper PCE )

[HJ2]

We are looking at 2 possible products:
NOC: To fit cars with NO Cat or eliminator (S2 completely de cat or SE).
PCE: To fit cars with a piper Pre Cat Eliminator.

1. NOC - Phil (surfboardfiller)
2. NOC - Phil (surfboardfiller)
3. NOC - Steve A, depending on results and price for an SE
4. PCE - esprit888 (LHD FED car)
5. PCE - Pinky
6. NOC - rip
7. NOC - HJ2 (duh!) (should fit my S2, with aircon and 2,25" Piper / Peco, and include O2 bung)

[Monty]

It's definately an upgrade but I'm not convinced by the separate pipe.

I have no idea on the seperate pipe, just went with the group buy at the time as that was the only thing available.

IIRC Dave M went with the sperate pipe idea.

Just to note that Marie`s custom pipe for the Garrett turbo also does not have the sperate pipe and if IIRC the one on the Shark didn`t

It will be an interesting thread.


ps, i need to have the O2 bung fitted as i`ve got an O2 sensor which i want to fit

[esprit888]

It does make more sense, then we are at the one style? I will also delete the PCE if the new one piece pipe functions the same as the PCE (also, as we are a whole lot tighter than the Isuzu RS, if it fits in the Elan it should fit the Isuzu making for an even wider taget market)

Phil,

I'm not trying to hijack the group-buy thread with a discussion on the item (I can do it without trying, being a BOLLECKS member ).....

....to fit a new downpipe to the existing Piper PCE may be counter-productive, as the PCE is basically just a funnel - as such, would we not just be creating more problems by opening the flow out, just to squash it up again?? (or am I missing something obvious??).

Would flow be better to go from wastegate housing straight to the piper exhaust, and just remove the PCE (ie as per the original idea).

Whilst i have obviously spent money on the PCE (which gave a good improvement), i would prefer to get something worthwhile from this project and end up removing it if necessary, as opposed to getting a half-improvement by keeping it and upsetting the flow.

Just a thought........

(in which case - anyone wanna buy a Piper PCE )

[surfboardfiller]

Geoff,
I am not saying don't separate the flow, I am saying 2 seperate pipes looks wrong.
I am also saying I don't know what benefits a split flow has, as I am not an expert on gas flow but this should be looked at by someone who is an expert on gasflow. I only want the best product for our cars.
The stiffy is strange and seems over complicated to me but I am no expert.

Pinky,
Tom at piper asked me to include a PCE compatible option to gague interest, personally I would remove the PCE and fit the full pipe.

To clear up the other questions:

There will be a fitment for an O2 sensor on the downpipes. If you don't have a sensor then a bung will be fitted to blank it off just like the OEM pipe on the Elan SE and S2.
This will fit Left and Right hand drive cars hence the title UK and Euro spec
This will fit cars with Air Conditioning fitted (An air con car will be the test car for Piper to play with)

I need to find out if:
This will be compatible with other pipes
Compatible with the Fed car

Phil

[surfboardfiller]

... and no separation of the wastegate pipe.

I am not convinced by the separate pipe, looks wrong to me.

Sorry Phil, bur Stevo's stiffy looks wrong to me. If they're not split adequately, turbulance will affect the ability to control the boost - take a look here at the bit after 4:05.

Ahaa! I just watched your video and it all makes sense to me now!

Recently I was looking at the new McLaren V8 Twin Turbo Engine and the exhaust pipes weren't fitted, so I could see the waste gate and the turbine in the same housing with no split.
I was not sure why there was a separate pipe on the Fed downpipe and didn't get a good enough answer when I asked, to help me understand.
It's all about turbulent air from the waste interfering with the exhaust from the turbine.
Of course the McLaren housing was very different to ours so (as I expect) would have been designed to eliminate turbulence and negate the need to separate the flows.

[HJ2]

Idealy the exhaust side of the wastegate should have the shape of an 'ideal' nozzle (yes, is IS rocket science...). exit diameter min. 3x throat diameter, expanding section @ 45 degrees, and inner radius of minimal 3x throat diameter. Further details at request

With this shape, the exit jet will be homegenous and parrallel flow, just what you want. It is however not superesomic. So interaction on the turbine side of things is still plausible. However the effect of the interaction will be minimal with an ideal nozzle. The sperate pipe will do exactly the same thing, (injection and impinging further downstream) only heavier, more complex by design and more heat stress will be involved due to different heatloads, and cooling areas of the structure (temp variations cause stress). This all in a nutshell since typing on an iphone is not my hobby.

[surfboardfiller]

Idealy the exhaust side of the wastegate should have the shape of an 'ideal' nozzle (yes, is IS rocket science...). exit diameter min. 3x throat diameter, expanding section @ 45 degrees, and inner radius of minimal 3x throat diameter. Further details qt request

Witj tbis shape the exit jet will be homegenous and parrallel flow, just what you want. It is however not supeesomic. So interaction on the turbine side of things is plausible. However the effect of the interqction will be minimal with an ideal nozzle. The sperate pipe will so exactly the same thing, only heavier, more complex and more heat stress will be involved due to different heatloads, and cooling areas. This all in a nutshell since typing on an iphone is not my hobby.

That sounds like a mathematical description of McLaren waste/exit! I could post a picture but I'd get sued and never work there again, so I probably won't.
I request furthur details (when you have a proper keyboard to type on).

[steve matthews]

Phil, I see from the video you have been doing your homework.
I do not know why Billy at Knox has not responded but I thought
all the questions were answered.
The research has been done many sources were consulted to obtain this
design. Less spool creating more power with less heat. What more could you
ask for.
I am all for building a better mouse trap and am interested in what Piper thinks.
The Knox pipe is currently installed and it WORKS.
Performance is best tested at autocross and track. My next track day is 3-26-11.
I love this upgrade and rank it at the top of the performance list.

The question that should be asked. Are the Fed. UK. S2 down pipes all the same?
If so the work involved with research and testing has been done.
If you do pursue a new design I would not offer a PCE option. Who wants another
gasket and bolts in their exhaust system.
Do consider ceramic coating over the old heat shields (this is 2011).
I wish you could experience this down pipe first hand, but that would mean
removal and shipment. This would leave me with the 1st production run.

Steve

[surfboardfiller]

Phil, I see from the video you have been doing your homework.
I do not know why Billy at Knox has not responded but I thought
all the questions were answered.
The research has been done many sources were consulted to obtain this
design. Less spool creating more power with less heat. What more could you
ask for.
I am all for building a better mouse trap and am interested in what Piper thinks.
The Knox pipe is currently installed and it WORKS.
Performance is best tested at autocross and track. My next track day is 3-26-11.
I love this upgrade and rank it at the top of the performance list.

The question that should be asked. Are the Fed. UK. S2 down pipes all the same?
If so the work involved with research and testing has been done.
If you do pursue a new design I would not offer a PCE option. Who wants another
gasket and bolts in their exhaust system.
Do consider ceramic coating over the old heat shields (this is 2011).
I wish you could experience this down pipe first hand, but that would mean
removal and shipment. This would leave me with the 1st production run.

Steve

Steve,
The fact that your down pipe has made a big difference encourages me to see the value in it and get this group buy off the ground, so it's not wasted research its an inspiration!
How much BHP do you think you gained with the Fed downpipe? I know 'BHP' is a bit of a fools paradise but Tom from Piper asked and I'd like to help him as much as possible.

Billy answered me but didn't really explain enough for me to understand how and why. I guess I need details like what the experts had said to them.
Are the Fed Elan pipes the same? I don't know and I don't know if the space arround it is the same either. Although I'd like to know. The UK S2 is basically an SE with a few different parts, one of those is the Cat.

For us it would be a lot cheaper to make it here and Piper already make the rest of the exhaust, they will be cheaper than a fabricator as they can set up for a production run. They also have to build to an actual car, not from plans so why not persue the best design? and I hope they can provide some expertise. Maybe it will turn out exactly the same as the Knox.

I agree on the PCE but Tom at Piper asked me to offer it to guage how much interest there is. So I happily obliged him.

I am considering the Ceramic coating, Monty and Paul P both reccomended it to me a while ago too.
I understand the inside is the most important surface to coat. But I don't know yet if Piper will offer it or it will be sent off for those who want it at extra cost.

I wish I could experience it too!

Phil

[esprit888]

Steve, maybe i missed the post but is Knox actualy going to be offering a production run? Timing?

Phil, I see from the video you have been doing your homework.
I do not know why Billy at Knox has not responded but I thought
all the questions were answered.
The research has been done many sources were consulted to obtain this
design. Less spool creating more power with less heat. What more could you
ask for.
I am all for building a better mouse trap and am interested in what Piper thinks.
The Knox pipe is currently installed and it WORKS.
Performance is best tested at autocross and track. My next track day is 3-26-11.
I love this upgrade and rank it at the top of the performance list.

The question that should be asked. Are the Fed. UK. S2 down pipes all the same?
If so the work involved with research and testing has been done.
If you do pursue a new design I would not offer a PCE option. Who wants another
gasket and bolts in their exhaust system.
Do consider ceramic coating over the old heat shields (this is 2011).
I wish you could experience this down pipe first hand, but that would mean
removal and shipment. This would leave me with the 1st production run.

Steve

[cliff]

We are looking at 2 possible products:
NOC: To fit cars with NO Cat or eliminator (S2 completely de cat or SE).
PCE: To fit cars with a piper Pre Cat Eliminator.

1. NOC - Phil (surfboardfiller)
2. NOC - Phil (surfboardfiller)
3. NOC - Steve A, depending on results and price for an SE
4. PCE - esprit888 (LHD FED car)
5. Maybe PCE (but probably NOC!) - Pinky
6. NOC - rip
7. NOC - HJ2 (duh!) (should fit my S2, with aircon and 2,25" Piper / Peco, and include O2 bung)
8. NOC - Cliff

[knoxmotorsports]

Steve,
The fact that your down pipe has made a big difference encourages me to see the value in it and get this group buy off the ground, so it's not wasted research its an inspiration!
How much BHP do you think you gained with the Fed downpipe? I know 'BHP' is a bit of a fools paradise but Tom from Piper asked and I'd like to help him as much as possible.

Billy answered me but didn't really explain enough for me to understand how and why. I guess I need details like what the experts had said to them.
Are the Fed Elan pipes the same? I don't know and I don't know if the space arround it is the same either. Although I'd like to know. The UK S2 is basically an SE with a few different parts, one of those is the Cat.

For us it would be a lot cheaper to make it here and Piper already make the rest of the exhaust, they will be cheaper than a fabricator as they can set up for a production run. They also have to build to an actual car, not from plans so why not persue the best design? and I hope they can provide some expertise. Maybe it will turn out exactly the same as the Knox.

I agree on the PCE but Tom at Piper asked me to offer it to guage how much interest there is. So I happily obliged him.

I am considering the Ceramic coating, Monty and Paul P both reccomended it to me a while ago too.
I understand the inside is the most important surface to coat. But I don't know yet if Piper will offer it or it will be sent off for those who want it at extra cost.

I wish I could experience it too!

Phil

Phil, pardon my tone, i hope it does not come off in the wrong way.

I don't understand how/why you think that split pipes "looks wrong". If you are making something that looks right, it most certainly won't perform right. I know you want the best for your Lotus, we all do! But doing something where form follows function and trying to make the best is a recipe for disaster. I tried to explain best I knew how why it was beneficial to have divorced wastegate and turbine outlet pipes. I posted numerous charts showing ~18whp and 14lb-ft gained (which takes us to 201.6 WHEEL HORSEPOWER, the only kind that matters, on the STOCK turbo) over a PCE-equipped Turbo elan. The only major upgrade at the time was the downpipe and some ceramic coating. Sure, I massaged the turbine inlet and manifold outlets slightly, but that isn't going to make 18whp.

Why do you need "expert" opinions? Those cost MAJOR money, you know. I could call myself an "expert", but now that you don't like the way my separate pipes look, would you still listen to me if I told you my expert opinion was that the pipes needed to be divorced? Proof is in the pudding (dyno charts). Separating wastegate and turbine flow is beneficial becuase they are at different temperatures, different gas speeds, and different times in the pipes. If they all come out at once, the WG flow disrupts the turbine flow, which chokes the turbine (IE, the engine) and causes unwanted backpressure in the manifold, which raises IAT and makes the turbo work harder to push the same boost level.

I am certainly not trying to discourage this attempt at making your own pipe, but I think you and piper will find the reason they never made this pipe in the first place is it is not economical for them. I may be wrong, they may have droves of inexpensive chinese children who are expert tig-welders, but I doubt it. Fit up is a very delicate process and the only expert I would consult is a welding expert for the fitup and fab.

What we need to determine is just how different the engine bay in front of the engine actually is between the FED/ROW cars and the UK cars. Because our pipe fits a stock AC LHD car! And it is not like the AC on UK cars is on the other side of the bay, and its not like the exhaust exits somewhere else (the exhaust kits are the same one and all), so I fail to see why we need to take yet another slice out of the already teeeny teeeny LEC pie by initiating another group buy for a yet-unmade pipe. We have one, and it works. I just need someone to actually post some helpful information about how and how much different the UK cars are from everyone else's. If the S2 is an SE with a cat, and the S2 downpipe enters/exits in the same spots as the FED downpipe (the OE one, not ours), then it should be pretty easy to find out if our downpipe will fit on a UK car....

The stiffy pictured above, that stevo/dico had is a horrible design because it will still be very turbulent (more so, in fact, than the OE design, which at least has a divider in it!). But at least they tried, which is important, and actually acted as inspiration for us.

We built ON THE CAR, not from plans. First time round we just copied the stock piece, which was a bad idea. Water neck was majorly in the way.....and it wasn't the best, so it didn't leave our shop (except on Steve's camera). What makes you think ours isn't the best design? I don't think you'll save any money in the long run with this idea. The only thing I can tell that is expensive from our standpoint is shipping to UK, which can be arranged affordably. Heck, the dollar is down compared to other currencies, I would think you guys would be clamoring for something made in t he US to take advantage of the economical situation.

You won't find many places to do a meaningful ceramic coating on the inside of the pipes. None of the guys here will touch that kind of stuff, unfortunately. They say it is too hard to keep it flowing properly and it ends up thick/thin in spots. If you are worried about corrosion, start off with stainless. We aren't worried about corrosion on the inside of the pipes.

I hope it doesn't turn out exactly like ours But at the same time, given this discussion, I hope it does.

[surfboardfiller]

Firstly I think you should read my last post again, it covers some of your points.

Phil, pardon my tone, i hope it does not come off in the wrong way.

I don't understand how/why you think that split pipes "looks wrong". If you are making something that looks right, it most certainly won't perform right. I know you want the best for your Lotus, we all do! But doing something where form follows function and trying to make the best is a recipe for disaster. I tried to explain best I knew how why it was beneficial to have divorced wastegate and turbine outlet pipes. I posted numerous charts showing ~18whp and 14lb-ft gained (which takes us to 201.6 WHEEL HORSEPOWER, the only kind that matters, on the STOCK turbo) over a PCE-equipped Turbo elan. The only major upgrade at the time was the downpipe and some ceramic coating. Sure, I massaged the turbine inlet and manifold outlets slightly, but that isn't going to make 18whp.

"If you are making something that looks right, it most certainly won't perform right" I don't agree with that at all. But I think you maybe confusing the words 'right' with the word 'pretty' and the word 'wrong' with 'ugly'

The pipe looks wrong to me as it is unevenly heated and the two pipes will expand and contract at different rates. I don't care about aesthetics when it's a part that will be purely functional. I see Engineering data on a daly basis and am familiar with the Jaguar and McLaren turbo engines, neither have separate pipes.

I have no doubt your solution works as I posted before. And your figures are good and helpful. But there is more than 1 way to crack an egg.

Why do you need "expert" opinions? Those cost MAJOR money, you know. I could call myself an "expert", but now that you don't like the way my separate pipes look, would you still listen to me if I told you my expert opinion was that the pipes needed to be divorced? Proof is in the pudding (dyno charts). Separating wastegate and turbine flow is beneficial becuase they are at different temperatures, different gas speeds, and different times in the pipes. If they all come out at once, the WG flow disrupts the turbine flow, which chokes the turbine (IE, the engine) and causes unwanted backpressure in the manifold, which raises IAT and makes the turbo work harder to push the same boost level.

I am listening to everything you have to say, but I am not easily convinced that just because your design is better than OEM, it is automatically the best that can be done. Lets see what some other experts have to say Personally I respect what piper do.
There is no doubt the old down pipe needs improvement, that is the purpose of this thread.

.... I fail to see why we need to take yet another slice out of the already teeeny teeeny LEC pie by initiating another group buy for a yet-unmade pipe. We have one, and it works. ....

I didn't see a group buy already posted on the forum and I don't see LEC as a pie to be sliced up amongst profiteers, it is a forum of people who have the freedom to choose. I will make no profit from this group buy so I don't care about how much of the pie goes where.

I asked Piper to make me one to fit the excellent product they already sold me. A group buy for Europe and UK makes sense to include others like me and spread the tooling cost for everyones benefit.
Why not let people decide where to spend their own money. Do you have a price for your pipe, is it available? Does it come with a garuntee? do we have to ship it back to the states for repair/replacement.
If you can include postage to the UK and UK import duty it would give a clearer picture of final cost to us.

You won't find many places to do a meaningful ceramic coating on the inside of the pipes. None of the guys here will touch that kind of stuff, unfortunately. They say it is too hard to keep it flowing properly and it ends up thick/thin in spots. If you are worried about corrosion, start off with stainless. We aren't worried about corrosion on the inside of the pipes.

I hope it doesn't turn out exactly like ours But at the same time, given this discussion, I hope it does.

Ceramic coating is not part of this group buy. As I wrote before, it would be extra I don't know if Piper offer that service but that isn't what this thread is about. Its not an issue of corrosion.
As I posted before, maybe it will turn out like yours.

You come across as if you resent my thread and want it to dissapear, it's a shame.

[knoxmotorsports]

Certainly didn't want to come off as resentful.

Of course the pipes expand/contract at different rates...that is why we included the flex bellows, which is how nearly all F1 motors (when turbocharged) controlled pipe expansion and prevented cracking. "Unevenly heated" i am not sure where you are going with that. Wastegate gases are considerably hotter than discharge gases (whose heat has gone a bit to spin the turbine) but again, that's why we have the bellows in there.

I did not mean to imply that mine is the best that can be done (because the best would be replacing that manifold as well!). But, I have seen what folks have done in the past and have not been impressed, either in fit/finish or execution. The packaging constraints present in the standard turbo/manifold setup are pretty hard and fast. We thought we nailed it with the first iteration, but it was too close to the water neck off the block, and way into the A/C compressor, so we redid it. Some how or another, the pipe has to exit toward the left (looking in the engine bay), snake down and nearly do a 180 and then twist back underneath the car. The only other major limitation we had was our mandrel bender can only do 3" radius pipes for both 1.5 and 2.25" material, so we are limited by how tightly the tubes can bend within one another.

I have not started a GB thread yet, I have no problem that you have done so. Nor am I a profiteer. Believe me, I wouldn't be making nearly one-off pipes for small production sports cars if I were....we'd be making exhausts for hondas or something similar (do not want!). But there are only so many of these pipes that will be bought in general, and I feel for you if piper requires a large minimum order and they don't all sell. I haven't seen their facility, but their pce and exhausts are very well made, so I imagine it must be pretty large/extensive, with lots of overhead and setup costs.

People are more than willing to make their own decision about where to spend their money. I do not have a price yet becuase price is inversely related to quantity, and I do not yet know Q. I will guarantee our pieces to be free of defects of workmanship (welds won't leak etc), but as you said, it probably doesn't make sense to send them back and forth like pilgrims for warranty work.

I have no idea how duty/import fees work over there, perhaps someone could educate me via PM> When we send things overseas, we declare the minimum value so as not to have to charge our customers duty. Shoot me if that's illegal, but duty fees should be illegal as well (I think). I would imagine the best way to ship a quantity of these pipes would be in a large box to a central address, and point to point shipping could be arranged from there within the UK.

[steve matthews]

Phil, wow all you engineer techno's don't get your panties in a wod.

I backed this project financially and the end result has far exceeded my expectations.
When I talk with the Knox boys I will request they make another prototype.
If Knox agrees I can ship the original from my car to you or someone of your choosing
who is willing to put it through its paces. This would be in the best interest of the
Elan community.
I believe in this upgrade,it has changed the performance of my Elan better than the
larger exhaust or Everest chip.

My next track day is 3-27-11. So you can't have it yet.

Steve

[surfboardfiller]

Certainly didn't want to come off as resentful.

Of course the pipes expand/contract at different rates...that is why we included the flex bellows, which is how nearly all F1 motors (when turbocharged) controlled pipe expansion and prevented cracking. "Unevenly heated" i am not sure where you are going with that. Wastegate gases are considerably hotter than discharge gases (whose heat has gone a bit to spin the turbine) but again, that's why we have the bellows in there.

I think they banned Turbo chargers in F1 in the 80's.

I thought this looked nice, brighten up the thread a bit: