Posts by gearhead

It's definitely more noticable with JRI's set in the soft range for cruising... The part of the drive belt under tension is above the swingarm pivot centerline. Increasing torque would increase loading on the rear suspension and vice versa. More than doubling the HP might make it really noticeable!

Well, someone took a Sawzall to a cheap wrecked import and created his own Vanderhall... Kinda...

Maybe the mechanics were supposed to take the grommets from the old swingarm and install them in the replacement swingarm... ??? But, I know what I'mma gonna do... Imma gonna take the grommets out of my old swingarm just before I take it in for the recall... That way, if they're missing in the new replacement swingarm, I can install the old grommets in it. I'll also demand to see the replacement swingarm before they start any work and check if the silver colored seal is facing outwards... Can't trust anyone anymore...

The shock damping rates change with the temp of the oil. Many shocks have some kind of internal bleed valve which compensates for the internal oil temps -- I know that Ohlins do. My butt-O-meter tells me that my JRI's don't seem to have this feature, but they are adjustable shocks so you can pre-compensate if you need to. Depending on use and roads, shock oils can get over 220F.

If you paint your springs, I'd avoid any powder coating which "bakes" them at high temps. No idea if that might change their temper or rates... Switching or swapping them out might be easier if you just want a color change. There are some high-rate racing springs (Swift's) which only come in one color (a burnt orange), so sometimes painting is your only option.

All of the energy absorbed by a shock goes straight to heat... So, covering it up is a good idea? You can cover up the brakes too to prevent all of that nasty abrasive brake dust from getting onto things. Sarcasm aside, the Slingshot isn't an off-road vehicle -- so the minor dirt on a shock/coilover might be preferred to frying the oil inside it.

Although our atmosphere has around 20% O2, some tires have several atmosphere's worth of pressure in them. The partial-pressure of O2 is then greater than 100% O2 at atmospheric pressure. This can start to spontaneously combust things. Aircraft tires, which often have 8 to 9 Bar (atmospheres) of pressure in them all run nitrogen. Given a high enough partial pressure of O2, aluminum will burn.

Ever let the air out of a tire and smell it? Smells like rotten eggs... The 2 to 3 Bar of pressure in a tire brings the partial-pressure of O2 up high enough that it's oxidizing the rubber. Your tires are rotting from the inside out.

Most street vehicles don't have 200 PSI of pressure in them. But, Nitrogen (no O2) will keep your tires happier longer. Also, N2 (the gas) has a larger atomic radii than O2 or other trace gasses. This larger diameter allows membranes or semi-porus aluminum castings to hold the tire pressure without slowly leaking.

Just my 2 cents.

I fabricated a safety bracket that holds the 2-bar MAP sensor firmly in place should the "clip" let go. I've attached a pic below. I've got decades of experience building prototypes, so 3D bent metal straps are almost innate to my brain... You know what they say -- "experience" is when you don't get what you want (unfortunately). One of the aftermarket Slingshot suppliers could offer a nice security strap -- frustration free. Just bolt it on. Great peace of mind.

If people do want to fabricate one, I suggest mocking up a pattern using thick cardstock or paper which matches the thickness of the metal stock you'll use. Then leave a bit of extra length. Pre-drill the hole to the manifold bolt, but leave the hole for the throttle-body until everything is bent to shape. That way, you can drill the hole at the correct length to apply appropriate tension/clamping to the MAP sensor.

It's not the best pic -- but the area under the fuel manifold has a restricted view.

Hope this helps...

I had installed my Alpha Supercharger some time ago... I do remember some mention of checking hood clearance -- either reading it on a forum or on some paperwork somewhere (can't find it just now). Anyway, for those interested in where and how much to trim, it's pretty simple. In fact, the hood framework already has trimmed spots from the factory for clearance to the valve cover. I've attached pictures here... [moderator -- you can move this post where most appropriate]

Just my 2 cents... Mind you, it's all speculation. But -- if the MAP sensor wasn't clipped in or if for some reason it didn't stay clipped in, irrespective of RPM (redline or not) you would not be running the correct air/fuel/timing map...

I've also got an Alpha supercharger -- I've had no issues with it. After checking the MAP sensor, it is possible to fabricate a very simple strap/bracket from a strip of thin aluminum that would secure it even if the clip lets go... A quick trip to the hardware store, a few bends, a few holes and presto... This 2-bar MAP sensor is a commonly used part for both turbos and superchargers. I do remember when installing it I had to press down REAL DAMNED HARD on it to get the clip to "click". A safety bracket would be a nice idea for all boosted applications.

Sorry to hear about the engine problems... I'm pretty sure that Alpha will help and do something about this.

Whoa whoa whoa -- wait... No no no no no -- that's not what I'm saying... Forgive my residual Asperger's syndrome... It's ALL COOL, supercharger A or B or turbo A, B or C. What I'm obsessing over is "horses for courses". It's also what Jeff was kinda saying. I'm looking at what people have run on this specific race (the SSCC) and it's "monkey see monkey do". It's rare that a turbo or supercharger would be in-boost for more than 20 seconds at a time. Think about it -- how crazy fast would you be going if you rowed through the gears holding the pedal down for a whole minute? These flat-out endurance type things are an insane thing to wanna do. That's what I'm obsessing over. But, I guess crazy is right up my alley.

Quote from Jeff@DDMWorks

I know the other SC is maxed out but our Rotrex SC is far from it. We start you out with about 280 hp and can ramp it up to the 350 range. And when this supercharger runs out ( your engine will give up before the SC will ) we can build you a stronger engine, bolt a larger rotrex unit in the exact same place, and without changing any of the original SC kit, shoot for the moon !!
Cams + Supercharger = Happiness
Granted this dyno run was with the supercharger on a Stock engine with our new cams. But it was only at 10.5 PSI of boost.

I don't mean to sound too defensive here but its friday and I am all hopped up on coffee this morning.
Supercharging the Scion FR-S With Jackson Racing | Speed Academy

Our Rotrex superchargers come to us from Jackson Racing. These superchargers are torture tested and used in racing all over.

Here are some quotes from the rotrex and vortech websites.

Rotrex: Rotrex A/S

"Rotrex dates back to the early 1970's when Anders P. Kolstrup - today Technical Director - being a passionate race driver, was continuously looking for improvements in engine development and performance. In 1996 the first patent was issued, followed by a string of international patents granted."

Vortech: About Us – Vortech Superchargers

"Founded in 1990 by Jim Middlebrook, Vortech Engineering, Inc. engineers efficient, high technology air management solutions for automotive, marine, industrial, aeronautical, and other motorsports applications. Since our inception, Vortech has been on the cutting edge of centrifugal compressor design technology, owning several patents, and winning numerous design awards, SEMA “Best New Product” awards, and countless racing championships in all manner of sanctioning bodies all over the world. "

Now as always its different strokes for different folks so you do what makes you happy. The Rotrex supercharger kit we designed for the slingshot is the most efficient, coolest running kit out there. And we have done a lot of research and testing to be absolutely sure of this.

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I hear that some guys double-up on the coolers for Rotrex SC's at the track. Which is great for running around in circles. However, if you run the Silver State Classic, you're WOT for 90 miles -- most of it straight and flat-out. Since the Slingshot has the aerodynamics of a parachute, it won't be setting any records. Just being able to stretch the fuel to finish while averaging a decent speed would be enough to satisfy my dream. But, that said, I know Vortech V3's have survived multiple runs of the SSCC while continuing to be daily drivers. Here's a short vid-clip of a Vortech equipped Mustang running the SSCC.

With my luck, a jackrabbit would hop out in front of me or a tire would blow... Still, nothing ventured -- nothing failed!

Just my 2 cents -- I went with Alpha's SC. Don't get me wrong, I think the guys at DDM are cool. But, I'm a Vortech fan. The Vortech V3 is bullet proof and user rebuildable. There are Mustang guys who run Vortech's V3 in Nevada's Silver State Classic Challenge... That's an open road as-fast-as-you-wanna-go race that's pretty much open to anyone. It runs on Hwy 318 from Lund to Hiko. And, V3 SC's have survived multiple runs of this race, year after year. Pretty much, you're WOT for 30+ minutes. I wouldn't put even money that the Rotrex would tolerate that too well... Check out the video on the link below:

It's been my dream to run this race -- at least once in my life... I keep telling myself "next year!" Then, life gets in the way...

NO NO NO NO NO NO NO

Watch the rear brake caliper clearance... I've personally tried wheels which had the proper offset but did not clear the stock rear brake caliper. Often, wheels which are advertised as "big brake compatible" have more clearance for wider brake calipers with the same offset. A 17" wheel may prove more difficult in this regard compared to the stock 18" wheel size. I used 45mm offsets on my rear wheels.

Just my 2 cents...

I doubt that ProCharger would sell a kit that had a propensity to go lean and blow-up engines... It could be that ProCharger is aiming at eventual CARB approval -- which would make their kit the only 50 state legal mod. A side benefit of using the stock injectors, is at least your MPG and Miles Remaining numbers on your dash display will reflect reality. Other considerations are that larger injectors may indeed deliver a lot more fuel -- but they may not retain an optimal spray pattern at lower fuel rates or when blowing into boost (where the effective fuel pressure seen by the injector is reduced). My experience with turbo mods -- is that you often get some stumbling or misfires when going full-pedal/off-pedal/full-pedal using larger injectors. This may not be an issue for the driver or the engine -- but the resulting emissions would certainly not qualify for CARB approval.

This isn't to defend or diss ProCharger... They probably had good reasons for the choices they made -- and not all of them may have been related to profit/price. I will say that their compressor mounting is old-school overkill... Dual plane brackets and fully triangulated. No chance of twisting from occasional spikes in belt tension.

Attached, as requested, the install instructions. The install instructions do say that you should have a factory service manual. The factory service manual would be the reference for installing the fuel injectors and MAP sensor as well as the proper torque for misc bolts.

Supercharger Instructions.pdf

My shipment came in 6 boxes. FedEx bashed the box with the supercharger and damaged the drain hose (whatta mess -- the supercharger comes pre-filled). I'm hoping that I get a replacement drain hose. At least the "oil" used in the Vortech self-contained superchargers is readily available... It's Royal Purple ATF -- off the shelf at places like Pep Boys. You can Google it for confirmation.