I'll start this thread by telling the story of why I bought my car and what the plans were, then I'll get on to the pictures.
Having recently graduated from college (2005), working in the auto industry, and living in the Detroit area I wanted to buy a sports car and I was adamant on buying an American product. When I saw the Sky at the auto show I was very impressed with the style and called a local dealership to put down a deposit. I took delivery in May of 2006 and immediately started planning/mocking up my turbo kit. My intention was to produce this in volume as a high end kit. I took on a "business partner" who was very knowledgeable but not very organized. After over a year we ceased communication and I was left with an exhaust manifold prototype that did not fit properly and an array of random parts I had purchased. I stared the project over, on my own, in the fall of 2007.
I worked with a great company on the new manifold. I made the necessary changes to make it fit properly and everything was moving steadily. I had the fuel system, pipe routing, intercooler mounting/placement, and tuning all worked out. The car was going to be completed in late 2008/early 2009. Then the market fell out. In one week my wife lost her job, my daily driver died, and my job was threatened. Sadly, I had to get rid of the Sky.
The project was left unfinished. Maybe someday I'll buy another Kappa used and finish the kit. At least that will give me some closure.
On with the pics!
Here are pictures of the first prototype. I was using a V-band flange on the manifold with a TiAL V-band stainless steel exhaust housing (GT2860). NO GASKETS! This required an external wastegate, which fit snugly between the turbo and head. This design was abandoned because I did not feel the tight placement of the wastegate could not be guaranteed with production variance.
I made the decision to switch to an internal wastegate in order to simplify the packaging and manifold design. This required me to change the merge collector in order to fit the new flange. The turbo placement changed slightly too, since I could pull the turbo closer to the head (and away from the power steering reservoir). Here's the completed manifold when it was tacked together. I'll have to get some pics of it now that it's done.
Hello I hope you can get it finished and all together, looks very impressive. Looks somewhat familiar to a company in Canada about three years ago, was that your collaboration with. Keep it up and thanks Norm
There was no collaboration with anyone in Canada. The only collaboration was between me and the shop that did built the manifold to spec. They were really great to work with (and in the US).
I forgot to mention that the head flange is CNC machined to transition from the oval port shape in the head to the round shape of the runners. Very nice. Everything is a smooth transition.
I was curious if there was any info on the advantage of the tubular vs log style?
Norm
Flow. In a log style manifold the exhaust gas exits the cylinder and immediately has to make a 90 degree bend, it's like hitting a wall. Then is has to pass by other exhaust ports on its way to the turbo. Pressure pulses from all cylinders are interacting and that can hurt the airflow.
In a tubular style manifold like mine the exhaust pulses are kept separated until just before they reach the turbine. They are brought together in a nice, smooth merge collector that also directs the pulses towards the turbine. You'll hear a lot of people talk about "equal length manifold's," which means the runners are the same length from the head to the turbo flange. That allows the exhaust pulses to (hopefully) reach the turbine one after another, instead of running into each other. My manifold has all the runners within approx. 1/4 inch in length. That's about as close as it could get.
The pluses for a log manifold are they are extremely cheap to produce, they allow you to place the turbo close to the head anywhere along the length of the engine, and you don't have to worry about an exhaust runner getting in the way of your downpipe. Bringing the flow of two runners together at a 90 deg angle to one another is not optimal for flow, to say the least. Look at some (if not all) of the manifolds being made for 2.4L Solstice turbo kits and you'll see that the runner design is total garbage. But it's cheap and makes packaging really easy!
A true tubular manifold has some flow adantages to a log style runner that can improve spool time as well as top end performance.
Manifold design on turbocharged applications is deceptively complex as there many factors to take into account and trade off
General design tips for best overall performance are to:
Maximize the radius of the bends that make up the exhaust primaries to maintain pulse energy
Make the exhaust primaries equal length to balance exhaust reversion across all cylinders
Avoid rapid area changes to maintain pulse energy to the turbine
At the collector, introduce flow from all runners at a narrow angle to minimize "turning" of the flow in the collector
For better boost response, minimize the exhaust volume between the exhaust ports and the turbine inlet
For best power, tuned primary lengths can be used
Cast manifolds are commonly found on OEM applications, whereas welded tubular manifolds are found almost exclusively on aftermarket and race applications. Both manifold types have their advantages and disadvantages. Cast manifolds are generally very durable and are usually dedicated to one application. They require special tooling for the casting and machining of specific features on the manifold. This tooling can be expensive.
On the other hand, welded tubular manifolds can be custom-made for a specific application without special tooling requirements. The manufacturer typically cuts pre-bent steel U-bends into the desired geometry and then welds all of the components together. Welded tubular manifolds are a very effective solution. One item of note is durability of this design. Because of the welded joints, thinner wall sections, and reduced stiffness, these types of manifolds are often susceptible to cracking due to thermal expansion/contraction and vibration. Properly constructed tubular manifolds can last a long time, however. In addition, tubular manifolds can offer a substantial performance advantage over a log-type manifold.
A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds
The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine's exhaust pulse energy.
For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1's exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2's ability to breathe properly, but this pulse energy would have been better utilized in the turbine.
The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.
Because of the better utilization of the exhaust pulse energy, the turbine's performance is improved and boost increases more quickly.
Perris - Thanks! Things have started to turn around. My wife started a new job about 6 weeks ago (after being out of work for 9 months!). My job seems more secure as well, but I don't know if I'll ever complete this project or if I'll just moe on to other things.
That manifold looks very impressive and nicely done.
I have a question though.....I saw that you were able to place the wastegate at the top, but decided to have an internal wastegate.
With my turbo kit, the wastegate is underneath.
What made you go internal instead of having that wastegate on top set-up?
With my previous kit (GT30), my wastgate was underneath and wasn't v-band. When I had the leak, and one bolt was off....I can't fasten a new bolt since its very tight down there. I had to remove the turbo, so I can replace the gasket and fasten a new bolt. Very laborious....even though I just need to tighten one single bolt!
With my new kit (GT35), the new kit design had a v-band wastegate (no more gasket needed)...but it is still underneath.
I think its better if the wastegate is on top, its easier to access.....compared to the bottom (like mine). Just in case there's a problem with the wastegate.
I tried to put it on the bottom, but due to the shape of my runners it was going to be a very tight squeeze with the motor mount. Plus, it would have made the piping worse. Check out how all the piping would have gone on the first prototype. The wasteage outlet would have been right next to the downpipe, so a short pipe with a smooth merge into the downpipe would make for a slick installation.
The runners are stainless (304 Schedule 10) but the flanges are mild steel. I could have done the flanges in stainless too, but the cost was rising rapidly. The mild steel should not be an issue if the manifold is properly coated.
I have considered selling the manifold on its own, but it would have to be understood that you will need to make all your piping (downpipe and compressor outlet to intercooler). Also, I have never actually fit this to my car, so I can't guarantee any fitment issues. Some of the welds ended up close to the nuts that hold the manifold on. But if there is any issue with that, a good shop should be able to make it work.
I would only want to sell copies to people that are mechanically inclined, or hooked up with a good shop.
sad to see sooooooo much work and no finish...hope things turn around for yuh....musta been tuff ......
__________________
BOOsted 2.4
42lb injectors
3" tubes front to back
10 boost
trim 50 garrett t3/t4 custom- bare bones pumpking
38mm tial wastegate / bov
custom i/c (BELL)
Werks radiator
aem wideband
gxp exhaust /magna flo - integrated dumptube ( b_faster and R&D automotive
custom manifold (sh**er the skunk )
hi flo cat
HPTUNING - the hard part !!!
(tune therapy -> randy @DDM)
JET-HOT 2000
aerologic egt kit
DDM backbone
AEM boost control
custom .08ss heatshield
The runners are stainless (304 Schedule 10) but the flanges are mild steel. I could have done the flanges in stainless too, but the cost was rising rapidly. The mild steel should not be an issue if the manifold is properly coated.
I have considered selling the manifold on its own, but it would have to be understood that you will need to make all your piping (downpipe and compressor outlet to intercooler). Also, I have never actually fit this to my car, so I can't guarantee any fitment issues. Some of the welds ended up close to the nuts that hold the manifold on. But if there is any issue with that, a good shop should be able to make it work.
I would only want to sell copies to people that are mechanically inclined, or hooked up with a good shop.
We're on the same page then. If you want to pursue it further, just PM me and we can talk more. I don't want to take this thread in a direction you weren't intending on.
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