Turbo vs Supercharger
 

I wanted to get some feedback from some of the great technical minds on this forum regarding the pros and cons of adding twin turbos ( exhaust driven ) or a supercharger ( belt driven ) to a Boxster :confused:

From what I can tell, adding twin turbos will give you approx. 60 hp for around $7k :

http://www.turbowerx.com/page1/page3/page3.html

TriGem2k, why are you considering this over a supercharger ?

Alternatively, a supercharger will give you approx. 80 hp for around $6k :

http://www.imagineauto.com/boxster%20sc.htm

ohioboxster, what made you go with the supercharger over twin turbos ?

Overall, I guess what I am wondering is this :

What makes one better than the other ?

Which would put more wear and tear on the engine ?

What are the advantages / disadvantages between the two in terms of performance ?

Thanks in advance for your input :)

Nick

with the SC you get NO leg and plenty of TQ. Plus you have companies that have been S/C Porsche for a while (IA (2.5 and 3.2) and TPC (2.5 only))

I have no clue who is doing the TT

Nick,

I went with the Supercharger kit for one reason only, price. I found a gently used like new kit on E-bay. I there would have been a twin turbo kit I would have bought that one. Turbo or supercharger is just personal taste. Its cool to say "I have a twin turbo Boxster" or "My boxster is supercharged" but as far as performance they are so close it will come down to opinion. I would never have paid 6 or 7 thousand and 2 thousand for install, would have just bought a different car. Thats just me because I dont keep cars for more than a couple of years and want to keep my losses to a minimum.
As far as wear and tear goes they are both air pumps and do the same thing, force more air into the motor which allows more fuel to be burned. I would think the only wear and tear factor is going to be the drivers right foot. Once again, my car only goes into boost when I put it there.
Im not sure at what point the turbo makes power, is there lag waiting for them to spool up? I dont know. The belt driven supercharger makes power right away when you stab the gas. As you know the Boxster is dead off the line. The supercharger makes up for the low end lack of power. I would have to ride in a turbo powered Boxster to form an opinion about the differences.

Thanks Nick, this is probably the longest reply to any thread in my life. My opinon would be keep searching or a used kit on the net if your considering forced induction. I honestly looked for months and cant believe I wasnt bidding against other forum members for the kit. I bid against one guy who didnt even own a Boxster but knew it was such a deal and I would have paid more by the way.

Do you have a "on/off" switch for your supercharger?

A used kit just sold for $2.6k
http://sfbay.craigslist.org/pen/pts/238617296.html

Yes, its called my right foot. I can drive my car the rest of its time on this earth without ever going into boost.

Oh ok I thought you installed a switch like in the old Corvettes w/ superchargers.

Superchargers are better for the Boxster because of a lack of room in the engine bay for turbos and a good intercooler kit.

JP,

They claim the boost kicks in at 2500 rpm, so I don't think lag would be a problem.

Ohio,

Sounds like you got quite a deal, plus the fact you did your own install :p

Todd,

Looks like this kit includes the intercooler...

They bring up a good point, Porsche has chosen to add turbochargers to some of their models, but not superchargers :

No forced-air performance application is truly complete without an intercooler. The TurboWerx upgrade kit includes an air-to-air intercooler for not only the safest possible operation, but additional hp. Not only just more horsepower - but just plain smart.

Thanks to the custom ECU programming, the intercooler and an extremely efficient turbocharger, the upgrade boasts a full 6 psi of boost pressure. The system is so efficient, that full boost is achieved at less than 2500 RPM. These performance levels are simply not achievable without taking a systemic approach to the design. The end result is a upgrade package unmatched in performance, reliability, and cost.

Performance and versatility. These are two reasons no others can match the power and boost level of TurboWerx Twin Turbo Upgrades. Using efficient turbochargers and intercooling safely allows 20-50% more boost than supercharging systems can provide - 6 psi vs 4-5psi. For certain applications, such as racing, TurboWerx systems can very easily increase the boost level for even higher performance. On the track or the street, turbochargers are the best choice. And no wonder turbochargers are what Porsche® engineers always chose.

http://www.turbowerx.com/page1/page3/page3.html

Thoughts ?

Nick

Yea and if you ever go for a ride with me you know my car is NEVER under 2500RPMs :D

In the IA video you can hear the SC wine. In mine since it is a 3.2 you cant since they have to add headers. I also have a Cargraphic muffler. It is schduled for cat bypass pipes this week ;)

As for Turbowerks I would feel better about them if they did not use photos from other websites (Techart & Porsche NA) JMHO

I have more plans not this motor but since I like this car so much and it is all but paid off. I hope to find a 3.2 or 3.4 sleeve it out to a 4.1 (alla Todd) do some head work and tune via IA, Tit connecting rods, pistons, Cams and and some N20... I figure I like this car that much and am already knee deep. So anyone who has a line on an engine please keep me in the know...

I will eventually do a wide body kit like an RSR so I can fit bigger meats under it. I already have issues hooking up. 1st is useless and 2nd is almost the same.

I really have no preference. Turbo vs. Supercharger makes no difference for me. I just want more POWER.

I made my decision to go with the Turbo on two reasons. I spoke with the guys at Turbowerx and the sounded pretty good about their product (what else would you expect from a guy trying to sell a 7k kit). I also spoke with my service advisor from Beverly Hills Porsche. Although he discouraged me with doing either, he said if it was to be done that I should stick along the line of the Turbo kit. He claims these engines would benefit more from a Turbo than they would with a Supercharger. So I set myself up for a Turbo.

The guys at Turbowerx claim their kit for the 2.7L will add 80HP and 90ft lbs torque to the Wheels. This would put my car at 270+hp at the wheels.

All that really matter is the end result and that won't be known until my pocket is 8k lighter. I will keep you guys updated as the project nears. Right now I’m hoping to have it all done by Mid March to Early April. Hence I will dub it "March Madness" :D

~James

Turbos would have a greater potential than superchargers. You can modify boost so much easier and in theory less strain on the engine (not belt driven, hence no parasitic loss). Now all you will need is some ceramic headers.

I sure would like a set of links for all the supercharger and turbo manufacturers for boxsters. If you've discovered them, please post them to this thread. Thanks!

Both links are located at the lower section of this thread.

Let just say in advance Im not getting defensive but you guys say some funny stuff. The service guy tells you the motor would benefit from a turbo over a supercharger, ok good enough for me. I would never settle for an answer like that.

You can modify boost so much easier and in theory less strain on the engine
Please explain this theory.

I can up my boost with a pulley change and how is one form of FORCED INDUCTION easier on the motor than another? I just wish people would speak from experience rather than what they read on the net. We are talking a couple ponies either way in favor of SC vs. turbo.

Forcing compressed hot air into a motor is just that, period. The delivery is the difference.

www.Imagineauto.com


http://www.turbowerx.com/page1/page3/page3.html

All I have to say is that a reputation is earned. The SC that IA uses is very similar to a turbo but does NOT need a I/C. Many of Stephens (IA) Kaspers’ cars have been in mags and he sits on the board for turbos of the PCA. As for boost adjustment, get it done once and be done do not try to play with it yourselves let those who have Mucho bucks in Cpu testing/programming and dyno time do that. I know I am making a strong point and may seem very biased but if you saw their shop and met the IA crew you would understand. They have cars shipped to their shop from all over North America every week. I just do not want anyone to us a system that has not been tested or has a solid backing behind it.

Preaching to the Choir man.... Ho is a Porsche/audi/VW know what will workbest on the car. They change parts out by the book. Nuances of tuning and upgrading s not their forte.

I agree with you Ohio. I for some reason just like the idea of the Turbo better. It really doesn't make a difference like you said, forced induction is forced induction. I'll let you know how it turns out once its all said and done. I wish I had something to compare it with. I don't know of anyone in my area with a Supercharged 2.7L. Oh well, I shall be the Ginny pig with the Turbo. If all fails ill make the 997 TT my daily driver :)

It is less strain because it doesnt have to drive a pully, not anything to do with forced induction. And with a turbo, you can change the wastegate so it holds more boost.

A turbo converts waste heat into energy to drive a compressor, so it is more efficient. If you don't believe this, measure the temperature of the exhaust gas before and after the turbine.

Now that's what I'm talking about. Making the car a blast to drive. Hell, I'm deep into mine already, so what's a little more $$$. I think I will keep mine around for the race/show vehicle but mod the crap our of it.

Josh, let's go take your car out in the snow. Let's have some fun. :D You said I can drive it anytime, I'll be over in 30 minutes.

-David

Hi,

A Super is Crank Speed dependent ± the Pulley used. Power comes sooner, little spool up time (lag). But, it loses something at the top end over a Turbo due to parasitic loss (you need more boost from a Super to achieve the same HP). Roots type are less efficient than the compressors in a Turbo. Vane type are about the same as a Turbo.

A Turbo comes on later (lag), but creates more power higher in the Tach with less Boost. More complex plumbing and Oil circuit (most Supers use a self-cotained Oil System). Heat Management becomes an issue, especially on a mid-engine.

I'm not yet convinced of using either on the Boxster w/o Intercooling due to the high CR and variability of available fuel. I'm skeptical of the longevity of a Boosted M96 engine. There are few high-mileage examples, so it is yet to be proven to my mind.

But, for simplicity, the Super kits are the better of the two for the Boxster IMHO...

Happy Motoring!... Jim'99

I can spin the tires thru 3 in the rain and you want me to go out in snow...hahahahaha

I would not even make it up the hill on my street. :cheers:

Jim,

Found another thread about this subject :

http://986forum.com/forums/performance-technical-chat/4189-turbo-supercharge.html

Look like your opinion hasn't changed much in the past year.

I am surprised you prefer the supercharger over the turbo for the Boxster, though...

Nick

Hi,

Doesn't surprise me that my information (or opinion) hasn't changed at all. I have had a fair amount of experience with Forced Induction both in Aircraft and Automotive applications. Each has their advantages and disadvantages. But these are not generic, rather, they often depend upon the application.

With the Boxster, being mid-engined, I think the Heat Management issues alone (let alone the plumbing issues) would outweigh the advantages of a Turbo. So, I would most likely choose the Supercharger route.

That's not an endorsement, at least without Intercooling, or some other way to prevent detonation given the high CR that the Boxster has...

Happy Motoring!... Jim'99

Trigem2k!

When you get your turbo set up, lets hook up and you can compair it to an NA 3.4l :dance: :cheers: :D

If you will get 270 to the wheels, it should be close to mine. I am in San Diego and would love an excuse to get up there to drive some of the canyons in Malibu!!

If you guys are spending 7k for the kit, and 2k for install, why not just go with a 3.4 conversion, with no detonation potential, no real heat issues, and no worries about going to FI on a high CR motor?

Theres no way I would go to FI on with the CR the M96 has with no IC.

I have an eaton SC on my E36 318i with no IC and the CR is 10:1. And that is pushing it but it only gets up to 6 psi. But it kicks ass when a E36M3 can't pull on me in a little ol 318 :dance:

I would imagine that they tune the ECU to accomodate the additional fuel required to match the FI, for either system, right?

Yes Jim but what do you do if the car doesnt detonate? You know even when my car continues to run for trouble free mile after mile I have a feeling there are people that will say "Fluke" or "Lucky". I just dont understand why several people say the car will detonate due to the compression ration. I drive my car everyday without issue. Let me clarify, Im not looking for an endorsement or even convince you of anything but just want you be aware 5 lbs of boost does not make the car detonate.

Upgrading a 3.2 to a 3.4 doesn't seem a logical choice for what you get. I mean, my 3.2 only has 24000 miles. Why would I want to upgrade that to a 3.4? Adding a SC to a 3.2 sounds like a good choice for me.

-David

Hi,

I never said your car detonates. What I said was that at anything over 8.5:1 CR, detonation becomes a concern. At 11.7:1 CR, it becomes a major concern.

Your car may be detonating at certain times and you're unaware of it, it may be doing so under certain conditions (Ambient Temp, Load, Fuel Quality, etc.). The DME may be compensating for it by using a detuned MAP, I don't know, I haven't studied your specific installation and all it's pertinent parts and those of the motor itself. But, if you are at times detonating, it's probably not enough to grenade the engine, but what are the longterm effects?

The rule of thumb is that anything over 10:1 CR requires Intercooling to be safe from detonation. Porsche doesn't force the M96 engine in any of their cars, what do they know that we don't? The Turbo uses a different engine. The TT engine (M96/70) is similar to the M96, but also very different - 8.4:1 CR.

Adiabatic Heating (a Gas rises in Temp if it is compressed) raises the Charge Temp 11°/1 PSI (10.9°/1 PSI to be precise). So, at 5 PSI, your intake charge is 55° hotter than the Ambient Air entering the Intake. On a 60° day, this means a lot less than on a 98° day, because the Charge temp would be 115° on the 60° day, but 153° on the 98° one. This heated charge will reach a detonation threshold (approx. 268°) a lot sooner in the compression stroke (where it is further compressed and heated) than Ambient Air charge would, which is what the engine was designed for (Pistons, Bore, CR). This means the engine must produce a spark sooner to compensate. How much sooner is it capable of? I don't know. How soon is too soon? Again, I don't know. But, it's the not knowing which concerns me.

Also, one bad batch of fuel and you could have serious problems. That's just too much risk management for me I guess...

Happy Motoring!... Jim'99

Why dont we all cool down. I am a fun loving teenager who is popular and a practical joker, thats my personality. Others may be recluse, obnoxious, meticulous, or just plain grouchy, but thats who we are and we cant change that. The problem arises when 2 grouchy people get into it and gripe at each other, so when the person accuses the other of being grouchy, they themselves are grouchy. Its just a forum, chill out, words dont hurt anyone unless you choose to react to them. We are all smart people on this forum (cant say the same for the integra forum, lol) due to the fact we drive a boxster in the first place. We are all adults, lets act like it.

Sorry but I can't see what problem you are referring to. Personally, I enjoyed the information and opinions shared in this thread.

Boggtown,
Jim and I have a difference in opinion and I dont believe we are out to hurt each others feelings. We have not made inflamatory comments to each other and I cant speak for Jim but Im not looking for a fight. If these comments were directed at us you are mistaken, if not disregard.

I am reffering to the entire forum, not a particular incidence, sometimes people can act a little strange sometimes. Im just trying to remind people that the more friends you have, the easier your life is. Life is your time spent with people you like and dislike, if you dont dislike anyone, your life will be much better. I just want you all to know your all my friends and if I take a long trip, I will try and stop by and say Hi to you all.

I think it is not a matter of like or dislike. People have differing opinions. These differing opinions differ because of the knowledge base they come from, and more knowledge is one main reason to visit a board like this.

While I have differed with Jim on one matter, I tend to think (based on his background) that he knows probably more than anybody on this board about what we speak to.

But that does not mean Ohio is bashing or unfriendly because he disagrees (or wrong for that matter).

But I too enjoy the exchanges on the board because it (hopefully) results in knowledge being spread about the Boxster, the car near and dear to all of our hearts.

So let the debating (friendly of course) rage, and let each state his facts.

but on the detonation issue, I am with Jim on this. Read this book called "Supercharger" written by Corky Bell, and you will understand much about how FI works in an engine. I have read it, and what Jim is saying is spot on about the ambient heat rise, detonation, and altering the ignition to avoid it.

Detonation is bad, and it IS very possible that the SC Box is detonating and you dont know it. Hopefully the ECU remap retards the timing when the knock sensors detect it. But even if it does, the fact it is trying to happen is a very bad thing, and does not bode well for the setup.

I wonder how (if any) of the IA SC systems have blown up the engine? Do they tell you? Do they warm you when you buy it?

My vote is for the supercharger due to the heat issue with turbos. I also will second the use of an intercooler, larger injectors, appropriate fuel pump, intake, etc...

Hi,

OH, I'm not sure our opinions are that different. Detonation is a well-known phenomena and is caused under certain conditions whether it's in a Diesel, Aircraft or Boxster.

It's also true that the DME can respond so quickly to the knock sensors that you may be detonating and not know it. Or, detonating at some times and conditions and not others.

Again, I'm not saying that you are, but I also think that you cannot with 100% certainty say that you're not either. You'd need a data stream from the DME to see if the Knock Sensors are detecting anything.

No malice, it's all good fun and learning. It's about truth, either it is or it isn't. Problem in this case is that there's 'evidence' on both sides of the arguement. Glad you're being the Test Bed on this... Keep up the Good Work!

Happy Motoring!... Jim'99

I drive mine every day I can with not one issue!

:cheers:

Liar, you didn't want to take it out in the snow with me. :D