@BKL:
Can you please describe the precise conditions under which you are perceiving a lean fuel mixture? There is an art to understanding AFR readings, as the optimal numbers vary based on RPM and load.
Tell me RPM, load, and engine temp, as well as the reading you're seeing.
Another aspect I seem to have noticed is that throttle response also seems quicker and less laggy, which is a sweet upgrade to any electronic throttle system, as they are already a bit slow to respond to fast changes in accelerator pedal. As this is a subjective analysis, I'd like to see what other users of the manifold say. What do you think, @lrobbi? Does it seem to respond more quickly to throttle input?
What would be attributable to this is, of course, the reduced air friction of the shorter, tapered runners and large plenum. There's considerably less inherent drag, delivering an air charge to the cylinders more quickly when the throttle is opened.
Just ordered one last night.
Thank you for your order. Yours ships early this coming week, please keep us posted as to results 
Took mines out for a quick ride last week, temperature was just about 48 degrees and the street was cold along with the tires. I was not able to get in on it hard but right away I could tell it was different. For sure more power but I cannot say what in numbers…if I was “butt” dynoing I might say 8 – 10 hp gain but that is just me and it could be greater. I need more time and warmer weather…. I am HAPPY with what I felt for sure. Feeling it pull harder at 3K on up was a nice feeling. (Running DDM Super Charger w/ upgraded smaller pulley
x2)
Thanks for the glowing review, and for helping show that this is also a great upgrade to supercharged Slings!
How does she feel with the stock PCM? How's the IDLE? Is the RPM band smooth? Does it feel like it lost a lot of low end torque?
Stock PCM tune works very well. Idle is as smooth and tight as the stock intake manifold. RPM gain is also smooth, and while low-end torque is somewhat reduced by the shorter runners, the manifold gives back in spades at midrange and high RPM. If anything, the resultant powerband is broader and more usable than the stock manifold, which becomes quite restrictive at higher RPM.
It's key to keep in mind that while the LE9 2.4 Ecotec has been a fine fit for Slingshot, it was originally designed for an automotive application. As such, the GM design objectives were to optimize midrange torque, even at the expense of maximum power, as that's the range a heavier vehicle used primarily for transportation seeks to be best in. In a much lighter, sporting application like Slingshot, we're not as concerned with optimization of that midrange powerband, and can use the benefit of better efficiency at higher RPM quite nicely. As such, the replacement of those long, torquey but restrictive intake runners with our shorter, tapered runners makes a tremendous difference in the engine's personality. With the StreetRace intake manifold, it pulls like a demon all the way to the 6500 RPM redline, rather than basically "falling off the pipe" as the stock intake does above 5000 RPM, where those long runners start to really create drag in the stock manifold. Further, as the Slingshot is also hampered by limited traction, taking some of that meaty midrange torque away makes it easier to get to full throttle without the attendant wheelspin. If anything, the new powerband is more driveable and manageable as a result, more linear without that big "bump" of torque in the midrange....and just more fun!
Of course, another airflow benefit is the new throttle body location. With no 90-degree bend just above the throttle body, instead a straight-through approach directly into it, flow/efficiency at high RPM is also increased.
Display MoreThat looks clean Bill. I cant really tell how loud it is. However I really like my exhaust that has been modified several times. It's as quiet as stock. Maybe even quieter. At 5psi I have a boost operated dump valve. So it opens up and has no back pressure. So I can sneak around and run over someone heals. And it does not hurt performance.
I posted this because I think most people don't want to hear the power till they really get into the gas. They are looking for a very quiet experience. That way they can talk whoever is riding with them. And you can keep your sanity when your just trying to find an open space in a parking deck. 4 cylinders just sound terrible at low rpm no matter what they are.
While your in the design phase you may want to see if you can muzzle it down to stock sound levels. And then provide a way to uncork it by using dump valves.
There is one catch though with my design. I believe it would have to be fabricated on each bike because of the differences in mounts and frame tolerances... maybe not... but it will be tight.
Thanks Rab! I can say with confidence that this system hits the mark on quiet at idle and cruise, and louder under load. The sound vids we are about to do will help solidify this critical aspect. With respect to dump valves, we're adamant about keeping the cost reasonable on this, as well as keeping it simple. The dual-pass muffler design has done an excellent job of controlling sound. For those who wish the quietest possible output, the included baffle tones it down nicely.
Relative to variations in frames, we've addressed this by the adjustable nature of the versatile isolation mounting system. We've test mounted it on several Slings, and been able to hit all the bases on proper clearances on each, so we're quite confident about fitment.
More to come!
Have you tested with headers yet?
Not yet. Even at 183 WHP, this was still with a stock exhaust manifold and stock PCM tune.
Click here for the Sneak Peek Video
After exhaustive research (sorry, just had to!), we are proud to present our brand-new, but two-years in the making, Slingshot Exhaust System!
This innovative exhaust system is the result of considerable development time, wherein we experimented with a variety of approaches in long-term validation comprising thousands of road miles. Some of you may have seen various versions of these prototype efforts at Slingshot meets. While they sounded and looked great, it became apparent along the way that rigid-mounting the exhaust system to the engine was producing less-than-optimal results. The significant additional vibration and resonance which this presented to the assembly proved troublesome to just about everything: mounting brackets, the mufflers themselves, tube welds...the gamut. As such, we were careful to not bring any such systems to market, and kept seeking our ultimate result. Another of our competitors (apparently now defunct) did introduce such a rigid engine-mounted exhaust...to less than spectacular results.
We've built complete automotive exhaust systems for many years, and know well that the best way to protect an exhaust system from such destructive vibration is to suspend it from rubber or urethane mounts. Such mounts properly isolate the system components from vibration, and this is what we've done here.
The first challenge was to create a versatile yet strong way to add such isolative exhaust mounts to the Slingshot, which unlike the automobiles we've developed systems for, enjoys no such mounting features. What we've developed are billet aluminum frame clamp mounts, as seen in the video and the pic below. These provide mounting points for the high-performance urethane mounts we've chosen. The brackets combine stainless steel fasteners with a dual-isolation system, as not only is the muffler assembly isolated from the mounting brackets via the urethane inserts, but the brackets themselves also ride on rubber isolation from the chassis. This mounting system is also inherently adjustable, as the mounting clamps can be positioned as needed on the chassis so as to properly align the exhaust on any Slingshot.
Once the mounting system was developed, we used one of our already-proven Magnaflow mufflers (as used to date in our turbocharged SidePipes system), but in a unique new fashion: we dual-passed the muffler. This enabled us to gain a total of 22" of muffling capability, as each sector of the muffler is 11" long. For maximum durability, we engineered the crossover passage using brutally-strong schedule 10 304 stainless steel elbows. This crossover feature is visible at the top of the muffler.
At the engine, we start with a thick stainless-steel flange and a triple-wall interlock liner flex section, which allows engine movement on its mounts without transferring that movement to the exhaust system itself. Our in-house mandrel tube bending capability is showcased in the strong 304 SS 16-gauge tubing sections.
The exhaust will be available in two versions: conventional bottom-exit (as seen in the video), or side-exit. In the side-exit model, we added what we feel is a clever feature: we routed the pipe through the body in precisely the same location as the Alpha side-exit exhaust, giving those owners who would wish to replace that exhaust the advantage of not having to also replace their side body panel. Like our Turbo SidePipes exhaust, we include an aluminum trim plate which uses stainless steel flathead bolts and nylock nuts to attach, rather than the pedestrian sheetmetal screws as used in the Alpha setup.
In testing to date, the new system has performed flawlessly, hitting all the mission objectives with ease: great looks, superb durability, and excellent sound. To that end, both the bottom- and side-exit version also will include an easily-installed baffle for a quieter tone, allowing the owner to choose their own preferred sound. Even without the baffle, the systems are not raspy or raucous; with the baffle, they are as civilized as can be.
What I personally enjoy tremendously is the tone characteristics. The dual-pass muffler design presents a wonderfully subdued note at idle and cruise, saving its louder personality for when we are deep in the throttle. The resonance of the system, its essential aural fingerprint, is dead-on perfect. You can play it like a fine woodwind, in that it will develop a variety of pleasing tones depending on RPM and throttle/load. The effect is not unlike a well-tuned motorcycle exhaust: musical in nature, and very fun to experience in all of its different flavors.
That said, what comes next are sound clip videos, which I will complete for each version this weekend. We've yet to determine pricing, but we do expect to come in a bit more expensive than the Alpha system, as there is more content here...and a much better assurance of long-term satisfaction, since we are not torturing the system with direct engine vibration.
The photo below is a development shot which shows the system sans tailpipe. The videos I'll present next will show both bottom- and side-exit versions in all their glory!
I’ve said this before Bill the product looks amazing and really dresses up the engine bay. Be interesting to see the hp difference with a SC. I wish I could of been your test dummy but momma said no. LOL
Thank you! We are working on a supercharging version that uses this intake manifold and our PortFueler EMS. News at 11
All our love to Angie and Bill from Aubrey and Bill. Miss you guys!
Heal fast and fully, Bill. 
I decided that I would just say congratulations to StickerDick. I had a long post above @Orangeman that I reread and decided it wasn't as nice as It should have been. I do want Mark to enjoy the win.
I will just have to wait till I can run on another 1/2 mile strip.
Still can't believe you let that Honda beat you. *hangs head in shame*
Congrats @StickerDick! You're making some serious stink with that Honda-powered Sling. As a purist, and a longtime Ecotec maniac, I have to give credit where credit is due...you've proven your unique combo is indeed formidable.
Best of all - I now have a 1/2 mile target to aim at! Talk is cheap, I know...now to get to the "walk the walk" part for me. As for you, you've made us all proud!
Display MoreI won't even try to remember the names of all the guys and gals that we met over the weekend there in Ocala but we had a great time and we're glad we had the opportunity to meet you all.
As for the racing,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,well,,,,,,,,, it was/is a little different than they type of drag racing that we are accustomed to. That being said there were a ton of similarities. It was definitely a lot of fun and even though there were a ton of vehicles there they ran it efficiently enough that you were able to get in several runs. Unfortunately the surface of the air strip was not the best for traction but as was mentioned before, "it was the same for everyone" which is true but it is also precisely why you cannot compare this weekends numbers to numbers ran at a "real" race track or even another air strip as their surface could be drastically different. Bottom line, this weekends race was "this" weekends race. Will there be another in the future? You can bet on that and next time we could be very surprised who shows up to play! While it's too late for anyone but Mark to win "this" race there is plenty time for anyone to show up and win the next one.
One of the things that I was impressed with is the belt. In the past I have worried about my belt breaking. That is no longer a concern of mine. Yes I have seen pictures on the internet where they have broken but I have no idea how they accomplished it. Let's think about Rabtech's set up for a minute. Without question he is a "plus" size guy, without question his bike produces serious hp, add to that the fact that he has tons of subs, amps, and other electronics mounted rear of center that add weight to the rear tire, then add on the fact that he was running a M/T racing tire that was soft and sticky and he made several runs without breaking a belt. All of these facts have taken away any concern that I have of ever breaking a belt. Will it ever happen? Who knows but you can bet if it ever does I either did something stupid or I just had a bad belt!
I will throw in a disclaimer out on this subject. If someone were to take a bike like Rabs to a really prepped track like maybe Valdosta GA during the Manufactures Cup Motorcycle Race then you may find enough traction to break a belt. The spring race is being held April 6th, 7th and 8th. If there is anyone here who knows @Bill from Hahn RaceCraft. I believe that he has the leverage to get some slingshots into the "grudge racing" class that is held at every ManCup event. They are motorcycle only events but considering our slings are classified as motorcycles I really don't know why there would be a problem. They usually have a TNT session on Thursday and Friday that you could also participate in and they are run pretty much like this weekends race where you can hot lap your bike over and over if you like as long as the session lasts. I'm not sure about safety gear, that is something that Bill would have to comment on. I am sure they would require the helmet but not sure about anything past that.
Tim how are ya! Good to see you, and thanks for the mention. Yes, I have broached the subject with my Manufacturers' Cup cohorts, and we may well be getting something going this year at some of the events.
For those unaware of what the Manufacturers' Cup Dragbike Series comprises, I'll be doing a thread soon on the possibilities where Slingshot are concerned. The series is the premier motorcycle drag racing series on Earth, truly internationally acclaimed and attended, and I am the series announcer and master of ceremonies. It's high time we got some three-wheelers out there to enjoy not only these amazing events...but also their phenomenal traction, as Tim alludes!
That said, I'll come back to this subject in a new thread once we have more to share - so if any of y'all have any questions about same, we can address them in such a thread, or you can PM me. I'd prefer not to "pirate" this thread, me mateys.
THAT said, congrats to all who participated in the Jumbolair event. I'd actually inquired about same last year, but they shut me down, as bikes were only first invited this year. By the time I learned of this, I wasn't able to get my ish together, as it was only about a month ago...and as my patient customers can tell you, I have NO time to be playing race-trike at the moment! Our shop mule Slingshark is in non-boosted, normally-aspirated development mode currently (more to come!) but will most assuredly be visiting one of the many 1/2 mile venues soon in one or more of its multiple identities, whether boosted or not.
A hearty and heartfelt Great Work to you all! Thanks for repping the Sling Nation 
Also another question...For those of us going to Maggie Valley (will be my first time), are there deals/installs to be had there?
Thanks for your enthusiasm! Will keep you posted on pricing. As to MV, I have to finalize yet with Ivor, but we plan to return this year, having taken 2017 off. If it all goes down and we are there, we will be shooting deals and installing
Display More.
How about any vendor willing to participate offers a guaranteed time-frame after the predetermined number is met and all participants have paid ...
Say something like if you don't ship within 30 days of the group buy completion (45 for custom powder-coat) you refund 5% per week overdue ....
.........
.
This.
I think it's a win-win for both customer and vendor. Incentivizing a desired outcome is a sure-fire way to help ensure that it is achieved...and on time at that.
So. What say we get back to the original intention here...Group Buy!
I'm game. I propose two tiers: a price for five Hahn SST SlingShot Turbosystems, and a price for ten. I'll post details later today/tonight. Anyone who'd like to express an interest, let me know here or via PM.
All of the problems straightened out, my fault. It is well worth going to this intake manifold. It pulls like crazy all the way from 3,200 rpm to the red line. I have not put many miles on it yet but did do 3 or 4 runs in second, third and fourth from 3,200 rpm to red line.
Thank you for being an early adopter! And also much obliged for the kind words about our product.
Have there been any apple to apple dyno comparisons with this manifold? ie; an existing CAI and free flow exhaust set up where a dyno is done before and after with the only change being the new intake manifold. At 20% the price of boosting IMO it would be nice to see at least 20% of the normal HP increased after boost for a break even on dollars per HP.
We did such back-to-back testing, and saw about a 10 HP max pickup when installing the intake manifold, with greater HP across the powerband, for a maximum of 183 WHP achieved with CAI, exhaust and this intake manifold.
The butt-dyno results so far have also been quite favorable, as @FunCycle attests to above!
A friendly aside: normally aspirated power is always spendier than boost per HP 
Display More..... glad to see you edited to specify "in the USA" ...
Since after they spent half a Billion dollars to acquire Saabs turbo and digital engine control knowledge in the '90's GM built a turbo version of the 2.2L Ecotec used by Lotus, Opel, Vauxhaul, and Daewoo from 1999 (for a 2000 model) to 2005 .....
the-real-reason-why-general-motors-once-sold-a-turbo-lo-1788600405
...........
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Yes, the USA market was my entire intention. I could see some clarification was needed, thus the edit.
Replacing the Twin-Cam and the dated 2.2 OHV as the new GM base inline four, the significantly more sophisticated Ecotec was introduced here across the US brands of Chevrolet, Pontiac and Oldsmobile in 2003 (with the remaining US and more global brands to follow in subsequent years), at which time we promptly added turbocharging to it...in of all things, the lowly Cavalier and Sunfire (progenitors of Cobalt to follow). The Cavalier instantly entered the 12-second range in the 1/4 mile with our new bolt-on Ecotec TurboSystem, much to our delight. The Sunfire stayed in our stable for a few more years, ultimately a 650-whp father-and-son project with my then-teenage son Adam. He'd manage a 10.5 second 1/4 mile @ 140 MPH with it, all with that base L61 Ecotec, heavily breathed on of course!
GM's Ecotec Turbos would bow four model years later, in 2007, on the same vehicle models we'd already been turbocharging for years.
