porsche mania

I'm sure the ceramic liner is only on the exhaust side to help with the heata

cweed

Very nice shop, following this thread/build is really interesting, thanks for taking the time to post it.

Only speaking for myself, but wish I enjoyed my daily work as much as it seems you do.

Santa Cruz Red

Hola... does anyone know if this build was ever finished?

Flat6 Innovations

It's still in assembly. The manufacturer of the valve train parts took forever with the custom valves and we just received them last week. I have the engine assembled to the cylinders now and will finish it over the next 8-10 weeks, now that we can finish the heads.

I'll update the thread with more pics when the time comes.

raffsracing

Great thread. I really like the finish you have achieved with the crank case.
I love big engines. I have a car with a tiptronic (not everyone wants a track car) & have been exploring engine options. A big engine only turning to 6500 with a lot of mid range torque is far more enjoyable to drive on the street than an engine that has to rev up consistently.
Can't wait to see the rest of the build.
I'm sure the dyno will tell the full story.
Give or take , what sort of expense will this engine incur?

Flat6 Innovations

I shoot for average HP and a flat torque curve. Anyone can make a ridiculous peak power number, but the engine is often worthless at many rev ranges. Unfortunately the vast majority of folks don't understand how to read, or interpret a dyno graph. That's one reason why I never post them to forums.

The investment in this particular engine is a little less than normal for the 4.1, as I did not utilize my billet crank. At the same time, it uses a brand new set of 50mm PMO carbs, which were not cheap.

All in all this one will tip the scales at around 37,500 of investment. Typically when I build an engine like this one personally, I propose the project in writing at 40k, and usually come in a little under that if they have a solid core engine to build from.

RaceDevelopments

Jake,

Curious who will be building the exhaust system (specifically the manifolds) for this engine?

Flat6 Innovations

Yours truly.

kos11-12

Hi Jake ,
Nice build, I have been following your work for many years on your web site and the Spyder forum , my aim was to build an R60,
Good luck with this project ,
, I will be curious to see the exhaust too, it seams to me that a lot of people are losing it all there ...

Flat6 Innovations

Its always been that way, but even more so today. Why? Because the vast majority of purchasers consider exhaust to be a fashion statement, rather than a piece to the performance puzzle. They are too concerned with looks, or sound, and efforts are often times impacted too greatly by these things.

When building and developing the perfect exhaust system, there's only one way to do it... Build the car around the exhaust! Packaging constraints with exhaust are the single biggest listing factor to what can be done with any exhaust system, in any car. These are compromises that we have to work around, and try to create an arrangement with the least amount of compromises possible. To do this, there are times when its impossible to end up with equal length primaries, and secondaries, and trying to get the lengths to match up equates to more bend radius, which is just as bad as an unequal length system.

Commercially available exhaust systems capitalize on the "fashion" part of the industry wen it comes to exhaust. Lots of money is wasted every year by people who consider looks and sound to be performance enhancements, when the opposite is generally the case. I have bolted on a 3500.00 system that cost the engine 27HP over a stock system, and I refused to let the car leave my facility with it fitted. The exhaust system manufacturer blamed the tune, and engine, even when I sent them data logs that showed 28 channels of data. Of course.

While I am sharing the vast majority of the things that go into building this performance power plant, exhaust is one area where you might be left with a big question mark. Sorry.

Fashion makes too big of an impact in the Porsche world these days, and its getting worse. There will be those who disagree with my statements, and thats fine. I'll take an effective arrangement thats clean, and does its job, any day over some system that "plays the part" aesthetically, but under performs in practical application. First and foremost, its an engine, and the damn thing has to run.

evoderby

Thanks for sharing your interesting project on here.

I feel the above statements neither do you nor the Rennlist community too much credit. If you do not want to share dyno sheets that's entirely up to you of course, the fact that we wouldn't know how to read them is utter BS....if you think otherwise please with sugar on top enlighten us;-)

As far as anyone being able to produce a ridiculous peak power, please enlighten me who they are? I know of only a handful of tuners who've seriously broken the 100HP/liter barrier with our N/A two valve aircooled engines....rest assured the packages to produce such goods weren't casually thrown together on a sunday afternoon. -if you know how to do that, you can certainly build a flat torque curve engine with less HP-

Your third statement contradicts your first I'm afraid, equal length primaries produce a peak in torque over a very limited rev range in the order of 200rpm. Where this peak occurs depends on length....which might very well be outside the effective rev range if not designed properly.

Unequal length headers (all things else being equal) have this torque peak occur at different rpm's for each individual cylinder, leading to additional torque being spread 'everywhere' rather than a localised spike.

greaser5

There's a whole lot of testosterone in this thread!

Flat6 Innovations

Ok, everyone has an opinion.

How about some glaze on top? When I hand someone ANY dyno sheet for ANY engine I see their eyes go straight to peak output 9 out of 10 times. Sometimes they wanted there 10 out of 10 times. I saw this in my last Porsche Hi Performance Engine Class that I instructed, where I teach people in the room how to understand a dyno plot. I actually had a video camera set up and then replayed the reactions of everyone in the room to the dyno graph they were shown that morning one by one.

This is because everyone is too concerned with a big peak number, and thats mostly driven by marketing and basing so much stock in that one peak value that might only cover 500 RPM of the engine's rev range, but might not be used more than 3-5% of the time in real time driving. This renders this value basically worthless to most people reading this thread, or buying an engine. The problem is that they don't know that, and the people that they want to brag to don't either. I don't sell dyno graphs, I sell engines that have gained a reputation of delivering usable power at all rev ranges, while maintaining manners that allow them to be driven everyday, anywhere. This has been earned, and it can't be bought.

When I do provide my customers with dyno plots I have to annotate them with ranges and descriptions to help therm understand what they are seeing on the graph, and how that will play out when they drive the car. Its tough enough making this happen on a 1:1 basis with the owner, and its impossible in a forum. Most people don't even know that HP is a derivative of torque, and that without torque, HP would not be possible. Others don't know that Tq and HP always cross at 5,252 RPM. Thank goodness for google, but too bad that people can't think for themselves these days without it.

They are everywhere! They are the "bigger is better crowd", and they are the easiest to beat. What it takes to make big peak numbers is a lot of cam, a lot of port, a lot of compression,a lot of intake, and a lot of exhaust. Thats it, just buy the biggest you can buy, and bolt it together and you'll be a successful builder of an engine that will dyno great! It may not have enough torque to pull a greasy string out of a cat's ***, but it will impress all your buddies and make them think that you were born to be an engine builder.... I learned this the hard way, back in the old days I didn't have a dyno; I'd accelerate as fast as I could up a large hill by my shop and see how fast I could tip the speedo at when passing the mailbox at the top of the hill. Real quick I learned that what made great HP didn't make the fastest car. When I bought my first dyno, I learned this even more, and let me tell you, I learned what my mistakes were really quick when operating a maul load valve and comparing how the engine responded to loads with various mods, and tunes. You can't read that in a book, and you can't buy it. It simply has to be experienced, and of course, you'll learn 100% of what you know from making mistakes, and breaking stuff. I've been known to change a camshaft in the same engine 28 times in a 30 day period, with back to back dyno work for every grind. I learned that 20 of those cam grinds needed to have their masters thrown away.

Tuners? Don't they work on Hondas? We build. We create. We tune to give the engine what it wants, but to do that you must first learn its language. I've broken 100HP/ liter with engines as archaic as an old VW Type 1, 2 valve pushrod based engine of only 1500ccs that made as much as 124HP/ liter normally aspirated. I've also done this with a 356 engine of 1493cc that made 127HP/ liter. Both of these were used for Land Speed racing, and both still hold standing records. Lots of people break 100HP/ liter these days with the -6 engine, but most of those are 3.2 and smaller engines. Those small engines are easy to turn to 9K RPM and make huge peak power from, but this 4.1 liter is a different story, or even a 3.8. I have learned that the larger the air pump becomes, the more difficult it is to create an efficient combination. As things get larger, the margins of error get smaller in terms of efficiency.

But how about creating that torque "plateau" while retaining a useful RPM range, and respectful peak HP number? Thats the hard part, or at least it always has been for me, and I have never gotten it "right" on the first try.

No, thats your perception, and like an opinion, everyone has a different perception of what they are reading, or being told. As far as the specifics of how an exhaust system (or anything else) will impact an engine RPM wise, depends entirely upon the engine, as well as the combination. No blanket statements here, sorry.

No, it depends on EVERYTHING! Everything is dependent upon everything else, not just the exhaust. I have made changes to primary length before, and right away the engine got lazy, but as soon as I manipulated the ignition timing, it woke back up again. The same goes with cam timing, as well as enrichment.

Yes, but if one is too caught up with "equal length" that they end up adding more bend radius to achieve the former, then they have wasted their effort. Dealing with exhaust is more sound wave control than anything else, and twists and turns effect those sound waves just as much as unequal length tubing. I pay attention to this when tuning intake systems, too, as I often see an exhaust change that isn't in the right direction lead to one or more cylinders that have odd looking spark plug readings, or noticeably more reversion at WOT at or near peak TQ, and then again near peak HP. Thats the stuff that a graph won't show you, you have to pay attention to everything, all the time.

But first all of this has to be packaged in the car, and in a rear engine application thats a challenge at times. This 4.1 goes into a 904 GTS, so I'll have plenty of room to do what I want, which will more than likely be a Tri-Y arrangement. Why? Because I don't care about peak numbers, and I'll trade them to keep the smile on the driver's face. Its also different, and will confuse people, making them ask "why?". I love hearing that word.. "Why."

Why I like the art of engine building, is because no one is ever wrong. Everything will work, but we have to work all of our lives to perfect our own style of engine creation. We never perfect it, and failure becomes a norm thats expected more than success.

HiWind

Thanks for taking the time to write that Jake .... Real insights make for great reading!

Tmistry

Dude, are you a wizard? My eldest daughter says that when she sees someone do something too amazing to describe and I say it here with a lot of respect. Thank you for the insight on this often confusing and ever evolving subject, I enjoyed the read.

When I rebuild, God willing, it's getting done by Flat6 Innovations.

Enjoy your Sunday's all/