Piper Exhausts turbo downpipe development thread

[Dave Eds]

Now now boys, play nicely..............

[surfboardfiller]

Phil, let's face it, if I gave you a 0 to 60 time from a stop watch you
would say (their needs to be 2 timers).
If I used two watches and a gps you would want 3.
I do not play these games.
Data is all that counts.
With Love and tender feelings
Steve

No mate I'd say lets test this properly, and you'd say but I brought my best stop watch.

Timing the cars performance gives comparable data, that's why manufactures do it. I'm not saying don't test the power plant, as that's crucial to development I am of the opinion that the timing of the cars performance is more relevant than data derived from just the power plant for the average consumer/driver; as is something that works in the real world a performance gain the customer will experience and attribute value to.
I see my term 'Real world' has confused some people but as I work with a lot of data it is a useful term used to distinguish information from something that actually happens out side the building in the real world.

I use the term 0-60 as an example of timing the cars actual performance and have stated several times since, that in gear times are less prone to human error.

If I wanted to sell a car or performance upgrade, I'd want to show the power output and the real world result of that in timed runs. If my Elan does 0-60 in 7 seconds I know I would rather buy a different car (or something is wrong). If my car has 0-60 and in gear times comparable with a Lotus Sport Elise I know I'll be competitive on track, if they are better than the best MX5 or GTi then I know I'll not be humiliated off the lights.

This is where I am coming from, if you are not convinced then that's fine with me but if you want to tell me I am wrong then why not convince me by answering the arguments I put forward instead.

This is my last post on the subject as I feel what I write is ignored and the debate going no where.

With love and hugs

[surfboardfiller]

Cheers, Billy and Dave

[HJ2]

No, please keep on posting! (but with a little less emotion )
You have a point here, and I know I'm not 'everybody' but I didn't ignore you but suggested to measure both! That's also where the debate was going
(now I'm feeling ignored... but i'm just the bloody foreigner )

[Dave Eds]

Bloody foreigners!

Phil, Billy (et al) - PLEASE keep posting/debating/listening/agreeing/disagreeing/arguing/contradicting or whatever - just please do it in a respectful way


Continue............

[cliff]

Sorry all but testing is postponed for a little while. My gearbox decided to start playing up, seems like it is the 5th gear problem.

viewtopic.php?f=48&t=14484&hilit=gearbox+nut+loose&start=60 Pity there is not a way to wirelock these nuts in place.

Fortunately I was close to Bob's place when it started happening & the car will be recovered to GST for repair. Many thanks to Bob & Gerald for their help.

Even worse than having to fly easyjet is that it is 35 degrees in Frankfurt today, Would have been ideal for a few autobahn runs.

To me it would seem like these figures would be more relevant to a road car, 30 - 60, 50 - 100 etc, after all that is was most of us want when we are overtaking or coming out of a bend. When I get it back, I will do a few runs with a stopwatch. I remember reading a thread about Base Timing where someone did that. It would be interesting to compare figures.

If we can all agree on a set of figures then I can have a go at them as long as we have some comparison.

For starters, how about:

Dyno figures (at wheels)
0 - 60
30 - 60
60 - 100
Timed ¼ mile
Top Speed (legally )

Any more you can think of, let me know. (Lots of unrestricted autobahn near where I work)

[HJ2]

Sorry to hear about the 5th gear problems
I'd say the table looks okay to me!

[Specky]

I'd require a few more pieces of information, here's what I would go for on top of the earlier mentioned things:-

i) Price, lets not fanny about...time to get the love spuds on the chopping block, what's it gonna cost!
ii) what are you actually testing, just the stiffy or a full system, Ported or unported wastegate etc
iii) what condition is the rest of the car in, are the injectors 20 years old, just overhauled, new or larger than standard
iv) Any other noticeable modiforcations that'd effect the outcome,BOV's, chip/ECU, short shift, gearbox ratio, wheels...
v) Elan Scan the runs, then we can overlay the data and do some comparrison work. We can also check out how acurate the Elan Scan data is.

Let''s draw a line in the sand and come up with the requirement for the tests and get it done and dusted.

I could throw some more data your way just for shits and giggles, Stevo's Stiffy on a Standard elan with 20 year old injectors.

Basically we seem to have a head to head challenge, let the best system win or forever hold your piece

Let the testing and evaluation begin....

TTFN

[HJ2]

Hear hear!
Let the games begin!

[DeeAitch]

I've never been a fan of 0 - 60 times myself - rely too much on the driver getting the revs right, being merciless on the clutch and getting the 60 bit timed accurately. And what I get will no doubt be tardy to some and maybe quick to others.
Also a lot of the best times you will see take out a gearshift (or 2). It can take over 1 sec just to change gear, especially if you have a celery stick for a lever. In days of yor I heard that some cars were deliberately geared so you could hit 60 in 1st, improving 0 - 60 time by whatever you would normally take to change up to 2nd. Definitly happen on on bike I knew which could do about 70 in 1st.
By the same token Lotus themselves were known to have a high spec engine fitted to press cars just so they could get a nice number in the glossy mags.
Best indicators for me are in gear times, say 4th. Nice if they also overlap. All you then have to get right are the start (needs to be steady speed at the start, no flying starts) and finish speed, not as easy as it may sound, and floor the throttle. Mine will be 5hite tho' 'cos I still have a miss on full load and probably little power after 140k miles
How about :
30 - 50
40 - 60
50 - 70
60 - 80 etc

Out of interest all these were around 4 secs in my TR7 V8 many moons ago !

[Specky]

All the data would be subjective, but the Elan Scan data would show you the speed of the gear changes, give throttle position so on and so forth, thus calculations could be made...

Then it'll be Lies, Lies and statistics.

When it comes to the crunch the stiffy the cost will be a few hundred pound or dollars and you'll get for a few extra horses, you could spend the same money on an overhauled set of injectors, get 3 or 4 times the horse power offered by the stiffy and still be below what the car rolled out the factory.

I'll watch with intrest,

TTFN

[dapinky]

My 2p worth......

....... i have the Piper 2 1/4" pipe, with PCE, ported wastegate, cleaned injectors, switcher chip (open and closed loop), re-built turbo, non-slipping clutch, good tyres and elanscan

I consider myself to be a consistant driver, with access to suitable lengths of flat tarmac and a stopwatch.......

Once a set of parameters are decided upon (by those who want specific data), then i am happy to do various runs over the same stretch of road at various switch positions (and even various static timing if it helps!).

I know that all cars are different, as are all drivers, and all states of tune, but at least it may give a 'practical / real-world' indication as to the time differences between various stages of mountain chip (with the bits i have upgraded, if not with a standard car)....

...from this data, it may give an indication as to how many horses loose how many 1/10th of a second on an overtake, and thus the power curve of the motor can be compared with real times, and so if an engine is putting out 200bhp, it *may* give a half second improvement, but it may not.....

....maybe this is on the wrong thread, as we are discussing the downpipe here, but it may give an indication of bhp vs real world driving, as everything else will remain as constant as i can get it....

... it even matters not if my engine has done 130K and yours hasn't, or if my wastegate is sticky etc - IT IS PURELY AN EXERCISE IN POWER TO SPEED COMPARISONS.

I have used the same bit of road for setting up the timing as per RIP method, and did the runs from 50 - 80 in fourth as a benchmark, but i didn't retain the numbers

The bottom line for me (as Specky says) is "How much will this cost me, and what will I gain" - TBH, with the PCE fitted, and a fat ba$tard driver, weight is of no huge concern to me, and i wouldn't expect to see a lot of difference - but who knows??????

anyone want to do the official observer / timekeeper bit????

and if you want to try and avoid parallax errors on reading the speedo, I have satnav built in, and access to acurate speed measuring equipment - all of which is a bit irrellevant, as the elanscan recording can be interpretted anyway and extrapolated (perhaps a WOT at about 40mph in 4th, and then the car will be under accelleration as it passes 50 (with as constant a tyre grip as you will get).... keep going until i see 80 and come off the gas - use the elanscan data/time between an accurate 50mph and 75mph, and it will reduce some other errors.

Any thoughts?

(I do realise that none of that will help anyone choose between the Knox and the Piper offerings, but it may help if one states an increase of 15bhp and the other states an improvement of 1/4 second to 60mph)

[bobbrown]

So where do the comparisons or the delta come from, you need a base line and you can not compare one Elan to another as even with the same upgrades they are likley to give different figures.
May be it's time to do some comparisons with what's out there now just on the time it takes to get from one speed to another and then see how that stacks up.
If you are going to use another car as a comparison it needs to be as close to the prototype car as possible less the down pipe, not sure how you can get close as tyres, road surface, elevation, weather etc can all effect the results never mind all the things on the engine that can effect the results.
As far as I understand it more work is needed on the prototype car as it suffers overboost at present as the waste gate is not ported and it runs the standard ecm so needs a chip.

As a point of interest If the new down pipe gives a gain of say 10hp then this equates to something around 0.2 of a second 0 to 60 which is going to be very difficult to measure even full tank of fuel compared to one low on fuel will effect the times by around 0.1 of a second never mind the weight of the driver but we won't go there. Even the roof will effect the times due to the change in drag.


Bob

[PiperRS]

Hello all,

I was not expecting this thread to go in the direction it has, i'm hoping we can keep things amicable here.

I decided to develop this downpipe due to the cost of shipping the Knox one over from U.S. makes its expensive.

We are not stating that our pipe is better than Knox, just better than standard, We have no intention of testing this over a 1/4 mile or 60-100 or any of that, but maybe rolling road figures of a car with standard exhaust over our exhaust/downpipe would be enough of a guide for people to decide. The reason we did not do a rolling road test with Clives car is due to the boost issue, i may have an independent garage lined up who may undertake the testing for us, but this is still in early stages and will take a while to complete.

Im hoping we will have a finished product ready soon, and that is when we will get the best result, fitted to your cars with your comments!

Let try and keep on topic.

[Steve A]

That's good, back down to earth with a bang , this thread was getting a bit like reading a "Max Power Mag" article,
lets get back to a realistic common sense approach.

It would be good to compare a standard set up, then downpipe, and then downpipe with Piper system, all on the same car otherwise it's open to debate again.

[Karl Martin]

Tom, I would still like your analysis on your design thinking.

Have you stayed with the Lotus original design because you believe it is the BEST solution or because it is the CHEAPEST solution, going for just a modest improvement?

Earlier in this thread, you did suggest that the waste gate section should join the exhaust pipe at the smoothest possible angle, (as in what every other engineer has told me), but have now appear to have produced the opposite. Why?

When it comes to price, if I spend £300 on a product that does not do the job well, I feel I have totally wasted my money.

If I spend £700 on the same product that works, it is money well spent.

On a different note, WITHOUT PREJUDICE or trying to upset Piper who have invested time and money here, I just cannot get my head around the fact that Knox. has designed, refined, constantly tested, on rolling roads AND in the real world, a superbly made product that ticks ALL the boxes.

So why look elsewhere? Why is this even taking place? What is it about the Knox design that certain people do not like and why?

How about Knox and Piper working together, with appropriate and fair division of profit?

As far as all this talk of testing, I have had my own experiences of just how confusing and inconclusive all theses things can be, given all the different variables....I have tested upgrades on my car on the same day, with two different sources and had two wildly conflicting results.

These days, I only care about how the car feels before and after any work, when actually driving. I know whether an upgrade has worked or not....I don’t need a set of paperwork figures to tell me!

[PiperRS]

Tom, I would still like your analysis on your design thinking.

Have you stayed with the Lotus original design because you believe it is the BEST solution or because it is the CHEAPEST solution, going for just a modest improvement?

Earlier in this thread, you did suggest that the waste gate section should join the exhaust pipe at the smoothest possible angle, (as in what every other engineer has told me), but have now appear to have produced the opposite. Why?

When it comes to price, if I spend £300 on a product that does not do the job well, I feel I have totally wasted my money.

If I spend £700 on the same product that works, it is money well spent.

On a different note, WITHOUT PREJUDICE or trying to upset Piper who have invested time and money here, I just cannot get my head around the fact that Knox. has designed, refined, constantly tested, on rolling roads AND in the real world, a superbly made product that ticks ALL the boxes.

So why look elsewhere? Why is this even taking place? What is it about the Knox design that certain people do not like and why?

How about Knox and Piper working together, with appropriate and fair division of profit?

As far as all this talk of testing, I have had my own experiences of just how confusing and inconclusive all theses things can be, given all the different variables....I have tested upgrades on my car on the same day, with two different sources and had two wildly conflicting results.

These days, I only care about how the car feels before and after any work, when actually driving. I know whether an upgrade has worked or not....I don’t need a set of paperwork figures to tell me!

Hi,

We have developed this part taking into consideration the cost of it, not just to ourselves, but to the customer aswell. In a ideal world it would be better to not have the waste gate pipe join the main flow at all.

hypothetically speaking, lets say there is a product that gives a gain of 5BHP and costs £100, then there is a product that gives a gain of 10bhp and costs £200.
Some people will go for the cheap one, some will go for the more expensive.

Taking that example, we have decided to make a part that, might not be of the best possible design, but is practical to manufacture, relatively quick to manufacture and will be at a reasonable price for what it is.

We would hope to get some rolling road results for this part to help people decide, but failing that, we should be able to get some user feedback and that will help people decide.

[Karl Martin]

“In a ideal world it would be better to not have the waste gate pipe join the main flow at all.”

O.K, so it’s the cost that is the issue.

Question, Tom....why don’t you contact Knox and see if you can you can pool your collective recourses?

Billy’s intellectual property, your manufacture. This way Billy doesn’t have to worry about excessive costs of exchange rates and shipping, as he has mentioned earlier and we all get a better product.

Obviously you are both businesses and need to make profits and where money is concerned there is always friction, but if fair play is exercised it could be good for all concerned.

Of course, Billy may completely reject the idea, but its food for thought.

You could still produce your cheaper alternative for those who want a compromise.

This is not a new idea.....Brit - Car- Nut posted the 14th contribution to this thread :-

“I would really love to see Billy, Phil and Piper get together and look at Billy's designe carefully. Maybe Piper can show some engineering improvements to Billy's design, but they are currently looking at a very early prototype of Billy's that doesn't fit any cars. Maybe all Piper needs to do is produce Billy's pipe for the UK buyers and Billy produce the pipe for the North American buyers.

I can remember thinking at the time, what a brilliant idea!

[norman lovie]

read this post with interest, mixed inside the comments are some excellent design feed back for what I was looking for ( i,ll be making my own down pipe this winter as part of my project)
I suspect the variance in performance versus design will be in the order of low % hp difference - as long as the basic design principles are kept ( keep the flow , direction change and entry exit points smooth and clean) and give the turbo plenty expansion room down stream - the % difference is important if your on a race track, but for me - my bumometer will probably not be able to tell the difference
how the engine responds with respect to pick up - drive throttle response etc.. for me - easy beats and extra 10 to 15 hp up top
so - thanks for the idea,s - and great to see - whatever design - a decent down pipe replacing the CAT etc. is going to enable a worthwhile response -I better buy a big bottle of argon this winter

[cliff]

Sorry for my lack of feedback lately, got my car back from GST last month but have been really busy lately. I had some time today, a rare occurance, & good weather, so I tried the Rip method.

I would mark the timingwith a line drawn on some duck tape attached to your rocker cover. Forget the timing light & advance it bit by bit doing timed 30-70 in 4rd gear.
Mine used to bang like mad on overrrun when set to 16btdc. It also used to burble to life. I quite liked the sound of both tbh. I got bugger all performance from boost & it used to overboost at 4100rpm.
Mine is now advanced more than 16btdc. Runs much better.

Sorry had a quick look for the original thread but can't find it.

So a couple of runs up a nice flat 4km road between villages. With the CAS advanced, the overrun has gone. Made 7000rpm with no overboost in 2nd & 3rd but started to run out of clear road. For sure, much better acceleration. So as someone mentioned before, maybe the changes we are making need different timing settings.

If the weather is ok tomorrow, I will have a play on the autobahn & try a few elanscans. (The things we do for LEC )