[cardinal_creek]

I've been following the topics about turbos and superchargers but I haven't seen any info outlining the positives and negatives of each.

The thought of *more hp* is intoxicating...but which is the better way to go?

I've inferred from other posts that turbos are more expensive, provide more hp and may be more prone to problems. Any of this true?

 

[mrclam]

the turbo is prone to more problems due to more moving parts but turbo provides more power the last time i checked

plus with a turbo you hit full boost at like 3k rpm or 4k(depending on the size of the turbo) where as with a sc you have to wait to bulid up boost then losign it right after you gain it

 

[Mcoupe]

Not only that with a turbo you can adjust the amount of boost you want.

So if you want to blow away that E36 M3 you just turn up the boost and away you go.

Rick

 

[EricK]

Many people say that the supercharger is the boost of the future...Turbo chargers have big noticeable power losses in the hot humid summer weather...With the supercharger you lose a lot of power to the belt...
Eric....

 

[HIBBoyScott]

Actually, I think superchargers were the preferred method of boosting and turbos were seen as inferior until some guy (known in Miata circles I think) popularized the turbo by showing what it can do using mathematics. I'll try to get more info on my current babbling later. =)

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By making this post I am not claiming to be an expert of any sort on the topic and should not be taken as such. It's just my opinion and worth what you paid for it.

[This message has been edited by HIBBoyScott (edited November 13, 2000).]

 

[GPR]

Turbos are more needy, you will have to upgrade more of your engine and accesories for a turbo over a supercharger. Think of it like this, daily driver, you should take a superchager. The power is there once you step on the gas which is good for freeway merging and lights. Turbos are good if you want to race. But it takes time for the turbo to spool up thus you have turbo lag once thats over you have an unlimited amount of boost/hp at your finger tips but just as much as your engine can take. Hope that helps

 

[JW]

What about a small, light pressure turbo? Like the VW 1.8T and turbocharged Volvos?

 

[EricK]

I think TEG will give the nod to Superchargers....

Eric...

 

[GPR]

the smaller the turbo the less lag and less boost you have. The bigger the turbo the more lag you have and more boost. If your not a hp power hungry person a small one will do. I doubt with that you will have to do very many mods, maybe a turbo timer and new oil/fuel pump just to be safe but i doubt even you will need to get those. A small turbo boosting 6psi you don't have to worry about much. You might want to look into lowering the compression ratio though. It will help your engine live longer.

I prefer a superchager over the turbo.

[This message has been edited by GPR (edited November 13, 2000).]

 

[tony]

Ok, this has been hashed out more than any other topic in Miata circles. Visit miataforum.com and do a search in the Power Mods forum for more than a fair dose of discussion.

Here's my take:

For most top-end power (ie, most hp), you'd go with a large turbo. Larger turbos take longer to spool and don't have the greatest low-end response, but make huge power later.

For low-end grunt, a supercharger or a small (particular ball-bearing) turbo will yield better results. Small BB Turbos can be into boost under 2k rpms and most roots-type (screw) superchargers start about there as well.

Mrclam, I'd venture to say that a roots-type supercharger has more moving parts than a turbo. In any case, superchargers generally deliver a more linear power increase, since they are "always-on". But they can also suffer from decreased thermal efficiency as well as parasitic drive loss (from the belt). Superchargers are difficult to intercool well, resulting in maximum boost of around 8-10 psi.

In modern turbo systems, there really isn't the lag that most people refer too. My miata, with its small bb turbo is on boost instantaneously, in fact, it's hard to keep it out of boost.

Both types of systems, with over anything past 6 psi, will require an integrated fuel delivery and timing management system. This could include, either more fuel pressure mapped to boost/vacuum or more fuel volume with larger injectors and electronics. For timing, you need a retard controller and/or knock sensor. Both of these could respond to any combination of boost, rpm and knock sense.

There's no really easy answer except that for HUGE power, you need a turbo. For most of us, the decision really rests not on Turbo vs. Supercharger, but against what kits are available for the car you're looking to FI. You need to weigh the advantages and disadvantages of those kits against each other.


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Tony
'01 Spectra Blue
'94 Turbo Miata

 

[HyperMKIV]

you also have to look at the different types of superchargers there are out there. centrifical ones have gained popularity in the past several years...paxton and vortec are great examples. they basically are the compressor portions of a turbo charger with a belt driven off the car's crank.

then there's a screw type and roots type. netiher of which i personally have tried, but we have done some whipple chargers on 5.0's...i think these are screw type (?) i forget which. another popular brand would be the eaton supercharger which TRD is using. this is another example of the screw type (?). i may be getting mixed up with screw and roots...so someone correct me if i am.

the thing i ponder is this...if turbo's make more power than superchargers, then why are the really big v8's using superchargers to make mad power instead of turbos???

this much i do know though, superchargers are generally safer than turbos, but not as efficient. i had a vortec supercharger in my 5.0 and i loved it. the power was always there, low end as well as on top (couldn't rev that high anyways). my supra is turbo'ed and i love that feeling too...although the two react very differently, i think both has it's good and bads. best thing to do, in my opinion, is to read up on all the different theories behind force induction before you jump into anything for your car. there's some great books out that specifically focus on superchargers and turbos. check um out...

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2001 IS300 Graphite Grey
94 Supra TT/6-speed/HardTop
90 Integra
86 Corolla GTS (AE86)

[This message has been edited by HyperMKIV (edited November 13, 2000).]

 

[HIBBoyScott]

Domestics use a supercharger because they like old technology, just like the rest of their cars.

Just kidding ppl, just kidding...

 

[TEG]

http://www.is300.net/forum_new/Forum2/HTML/000052.html
http://www.is300.net/forum_new/Forum2/HTML/000002.html
http://www.is300.net/forum_archive/read.html?f=1&i=5386&t=5386

 

[tony]

Originally posted by HyperMKIV:
the thing i ponder is this...if turbo's make more power than superchargers, then why are the really big v8's using superchargers to make mad power instead of turbos???

There's a reason for this, but I can't think of what it is at the moment. Big V8's don't need any help with low-end torque, but they can "run out of gas" at higher rpms. I think the supercharger, helps keep the power up. Why the turbo doesn't do this better, I don't know, but there is a reason.

this much i do know though, superchargers are generally safer than turbos, but not as efficient.

This is only because superchargers are usually driven at less boost than turbos.


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Tony
'01 Spectra Blue
'94 Turbo Miata

 

[SupraSport]

The real question is what exactly do you want? What kind of power levels are you looking for? What means do you want to use that power?..daily driving, drag, autox, sleeper? Do you want low-mid end power for getting around town in traffic, or do you want high end power w/no guts on the low end? The turbos on my car are set up to turn on at the same time and I hate driving it around traffic, I get passed up by everybody! Even with full boost coming on at 3800RPM,which they say is fast spooling, it sucks!..but running people from a roll to +100 makes up for it(im sure HyperMKIV knows what im talking about). Also are you willing to sacrafice warrantys and smog laws. Set a powerband level of what you want first and go from there.

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KP
94 6 speed
BPU

 

[TEG]

My biggest argument for supercharging over turbocharing is for drivability. With a supercharger (paritcularly a roots S/C) you maintain better control of power output. Playing with a touchy throttle on a twisy mountain road is alot easier with the linear power of a S/C blown motor as compared to the "rubber band" power output of a turbo'ed motor.

 

[IS300GTE]

actually, the main reason for this is familiarity and ease of use. most kits for v8's are superchargers are cheap.

but if you notice, the fastest mustangs are twin turbo-ed, and so are the fastest firebirds (drag racing) . also, it is very hard to get a turbocharger to work with a carbuerator, not impossible, but hard. the supercharger setup and kits work much better than turbochargers.

Originally posted by webmaster:
This is only because superchargers are usually driven at less boost than turbos.

 

[IS300GTE]

Originally posted by EricK:
Many people say that the supercharger is the boost of the future...Turbo chargers have big noticeable power losses in the hot humid summer weather...With the supercharger you lose a lot of power to the belt...
Eric....

that's not completly true, superchargers do also, all other things being equal. they are still forcing hotter (than cooler months) air into the motor, and hot air is still going to be less dense then cooler air. the denser the air, the more hp, all other things equal.

 

[IS300GTE]

Originally posted by GPR:
Turbos are more needy, you will have to upgrade more of your engine and accesories for a turbo over a supercharger.

that first line is not true. you can make the same amount of hp from a turbo, maybe more actually, as you can with a supercharger. the turbo can push the same amount of CFM into the motor, add that with spark fuel and timing, and the motor can potentially make the same power with either add-on. the turbo might even make more power at the wheels, because it doesn't have parasitic drag like a supercharger does.

 

[SupraSport]

Originally posted by TEG:
My biggest argument for supercharging over turbocharing is for drivability. With a supercharger (paritcularly a roots S/C) you maintain better control of power output. Playing with a touchy throttle on a twisy mountain road is alot easier with the linear power of a S/C blown motor as compared to the "rubber band" power output of a turbo'ed motor.

I totally agree with you. It is scarey when you think about it, driving fast through some twisties, braking for a turn, down shift, going from boost to zero boost, then gasing it and having full boost come on. This is where alot of unexperianced and some experianced drivers lose it. I let 2 friends drive my car and both almost lost it going through a corner. After that nobody drives my car but me. There is also a trick called left foot braking that is used in racing w/ turbo'd car. While going through a corner they would apply the brakes with their left foot and still gas with their right, this would keep a load on the turbos so boost does not fall and come back on drasticly. I think this is only possible with a seqential gear box.