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Discussion Starter #1
I've researched so much that my impression and understanding of my options has actually become fuzzier. Some of this has to do I htink with how old some of the information that I've found happens to be.

I'm considering installation of either the Rotrex supercharger kit from DDM Works or the stage 2 turbo charger kit from RPM Motorsports. If I understand correctly, both come with everything necessary including tuning support. The price difference is about $1,100 with the supercharger being the more expensive of the two. Maybe one or both offer discounts to members of this or similar forums?

The car is a 2006 2.4 NA with a 5 speed. Aside from the magnaflow single-exit exhaust, mechanically the car is entirely stock and has about 10,000 miles on it. I'll add drop springs soon, but this shouldn't be a factor in either choice.

I don't have plans to compete with the car. This is a street cruiser and what I'm looking for is as much power as I can add without inviting new problems - breaking parts, the need for a better clutch, constant tuning and adjusting etc. I'm more interested in improving low-end grunt than I am in making gains that are found near the top of the power band.

I'm a competent car guy and I've owned stock SC and turbo vehicles in the past, but I've never installed either system. I plan to do the install myself and make use of the tuning options that either supplier provides. This isn't a daily driver, but even so I don't want to spend weeks (or months as seems to be the case with some of the turbo installations I've read about) running down problems.

So - these are my goals and priorities. I'm drawn to the supercharger option, mainly because this seems simpler to install and maintain and I think it's probably also going to have a greater longevity and reliability. I also think that this will provide the amount of power that I'm looking for and that power will be in the part of the power band that I'm looking to improve most.

Am I correct in my impressions?

Am I overlooking anything?

What advice can you offer?

Thanks in advance.

Terry
 

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Superchargers add low end power. They wind up quickly and reduce boost as they reach the higher RPM range.

Turbo's generally start with low boost at the bottom end and start to provide serious boost as the RPMs climb.

For low end power the SC is a good choice.

I have seen both mods made. The turbo involved in my observation more work and are more challenging to make run correctly. The DDM SC kits of the past have been simple bolt on installs that have been successfully done by owners with limited skills in a day or two over a weekend.
 

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And a supercharger sounds WAY sweeter.
 

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Like bellybuttons, everyone that chimes in is going to have an opinion. I've driven both...not in a Solstice, but I've driven both. I have a turbo Solstice,just haven't driven a supercharged one. I had the privilege of driving an experimental Lincoln Mark VIII, 48 valve, V8 that was supercharged. And I've driven many turbo cars. As far as I'm concerned, while the Lincoln was fun on a closed course, the turbo cars feel way better for the "kick in the pants" feel.
 

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I had my 2.4 supercharged for a time with the DDM/Eaton supercharger, and I have my RL currently. The RL is more refined, quieter, and obviously easier, but the supercharger has a significantly better feel at the bottom end. While the RL has nearly imperceptible lag, the SC almost seems to anticipate throttle changes. Think about going faster and you do.

I have no experience with the Rotrex supercharger and it may be totally different, as it is centrifugal while the Eaton is positive displacement.
 

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I believe the fundamental difference between a SC vs a TC is that the SC needs HP from the engine to drive it. Whereas a TC uses power already produced by the engine. So free HP vs needed HP.

Also the Rotrex is a centrifugal supercharge which means you have to be in the upper RPM range to achieve maximum results. That's not something I'd want to do on a regular basis because I'd be concern that sooner or later somethings going to give, so that's something you might want to think about.

BTW, I love the sound of superchargers. :cool:
 

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I believe the fundamental difference between a SC vs a TC is that the SC needs HP from the engine to drive it. Whereas a TC uses power already produced by the engine. So free HP vs needed HP.

Also the Rotrex is a centrifugal supercharge which means you have to be in the upper RPM range to achieve maximum results. That's not something I'd want to do on a regular basis because I'd be concern that sooner or later somethings going to give, so that's something you might want to think about. BTW, I love the sound of superchargers. :cool:
Close, but not exactly correct.

There is a rule in physics that nothing is free, and the turbocharger is no exception. While it will consume less power overall than a belt-driven supercharger, the backpressure it generates does reduce the engine's net power output. It is also generally more efficient in partial or no boost conditions because the waste gate routes the exhaust gas around the turbine and reduces the mechanical losses, while a belt-driven supercharger is always turning proportional to engine speed.

The centrifugal supercharger is setup to make maximum boost at redline, and since the boost curve is roughly equal to the square of its speed, its boost drops off fairly significantly at lower RPM. The turbocharger is also centrifugal, and also develops its maximum effect at engine redline, so the high-RPM issue is similar for both. The benefit of the turbocharger in this case is that the wastegate control allows for more boost lower in the RPM band without overboosting at higher RPM.

The positive displacement supercharger delivers air in direct proportion to engine speed, so its boost is nearly constant and is the reason that it gives the best bottom-end improvement but the worst top-end. The centrifugal supercharger has less bottom-end boost than the positive displacement supercharger but will provide more at the top end. Because they are engine-driven, neither of them will exhibit lag, which is the main drawback of the turbocharger. The twin-scroll OEM turbocharger has very little lag, but a larger version or one that is single-scroll will not do as well.

They all have benefits and drawbacks, and none is absolutely better than the others, so the choice is down to your driving style and what you want out of the car.
 

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I hate it when you bastages start talking about this [email protected]#$. Mostly because you start doing it right after I've convinced myself my stock 2.4 is "just fine the way it is"....
Ah, but your stock 2.4 is fine just the way it is. I alternate driving mine with my RL and enjoy them both equally.
 

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I can tell you the rotex sc is an easy install. It does absolutely amazing things to the 2.4 all the way through the rpm range . I have one on a Polaris slingshot. I also agonized over turbo vs super charger, I am very happy with mine very little/no extra maintenance or drama.Call and talk to Dave he is a great guy and very helpful
 

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A vote for supercharger

This is an unabashed endorsement of the DDM Supercharger. I have two on 2.4L NA Solstices with automatic transmissions. The first was installed by me and a friend, then dyno tuned by ESTunes. The second one was installed by Dave from DDM at NASSAM2019. Both have immediate low-end torque, no turbo lag, and are a big improvement over stock NA. Disclaimer, I have not driven an RL or a GXP.

The first installation dynoed peak torque at 3300 rpm, then a rapid falloff, limiting hp to 238. We suspect exhaust restriction and will install a high flow cat. Still, it runs the quarter in 14.2, splitting two races with a friend's GXP with GMPP. Both times my car was ahead at the 1/8 and he caught me by the 1/4. 0 - 60 is 5.98.

I have not dynoed, tuned or raced the second car, but it feels about the same.
 

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As mentioned above if your looking for low end power a supercharger is the way to go . I'm in the minority here but after much research I went with a Hann turbo kit . The kit itself was easy to install did it over a weekend about 11 hours total time ,was complete nothing else to buy including the tune , the instructions were very informative and easy to follow and for $3500.00 including some upgrades for me a super deal . Almost all my driving is done on rural roads near me so it fit my needs perfectly .
 

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hmm always more questions.....with the twin scroll turbo does it have to have a twin/split exhaust header/manifold to work right?like the oe gxp "split" manifold, or will it still work right with a std header with single open outlet?? yes Im almost clueless with turbo's, Ive built a good few sc motors.(v8 stuff). I was considering a sc but that aint gonna help mpg any at all...
 

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Discussion Starter #15
Great - now I have to look at the Haan offering too! I took a peek previously but I see that I should look a little further. That said, I'm hearing nothing but affirmation for my preference of a supercharger over a turbo for my goals and priorities. Thanks again for all of the information and advice.
 

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hmm always more questions.....with the twin scroll turbo does it have to have a twin/split exhaust header/manifold to work right?like the oe gxp "split" manifold, or will it still work right with a std header with single open outlet?? yes Im almost clueless with turbo's, Ive built a good few sc motors.(v8 stuff). I was considering a sc but that aint gonna help mpg any at all...
It needs the split manifold to get the cylinder pair exhaust pulses arriving separately.
 

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I think that either supercharger or turbo would make you happy. I have had both (though not on the Kappas) and while I prefer the top end of the turbo when properly sized, just as many people will like the supercharger for the immediacy and strong low down torque. (A properly sized turbo also has excellent low torque, but in these cars it is programmed not to allow as quick torque production as possible to avoid damaging the driveline).

Decide what your power targets are. If you want high power, the GXP is the way to go - the stock engine already puts out what the 2.4 with turbo would, more or less, and it has a huge tunable margin still to go. If you like great acceleration for low speeds ad don't ted to rev an engine, the supercharger might make you happy.

The LNF engine was designed for turbo use; the LE5 was not, BTW.
 

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Discussion Starter #19
I did, and while I'm always interested in a deal I'm more intersted in a complete kit that I can install and will run as it is supposed to right out of the box. I appreciate the heads up, but I know enough to know that as a boost novice piecing my own system together will cost more in dollars, time, and hassles than going with a complete kit will.
 

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I did, and while I'm always interested in a deal I'm more intersted in a complete kit that I can install and will run as it is supposed to right out of the box. I appreciate the heads up, but I know enough to know that as a boost novice piecing my own system together will cost more in dollars, time, and hassles than going with a complete kit will.

Less hassle even though sounds like you have a nice car. Is look around for a nice GXP then sell yours. More to start with and if you need more plus all the electronics to control the extra power. Will be cheaper in the long run. When you go to resell you cut the buying pool way down with a modded car. Even more so with the age group that likes these cars. Supercharger with a short 1st gear will be a hand full before you get to redline. The ones I've seen just burn the tires and look like snooze you lose in a race. Supercharger does sound cool inside the car
 
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