supercharger or turbo?

[MANDALAY]

Both Turbo and SC ( centrifugal ) have their benefits and weaknesses.

The Turbo with the high temperatures in the bay.
The careful selection of size so as to get boost down low and still hold up top in the rpm range. Too big and there is lag
Oil lines
The aggressive build and shock to drive line components.
The off/part throttle weakness.
Restrictive on the exhaust manifold thus slowing the air out of the chamber and increasing the chance of detonation.
Just to mention a few.
But what you don't get is the smoothness of a N/A car.
With the correct turbo it can get close and will always have a lot of power under the curve

The SC Doesn't have the heat
Is always on boost so never a lag issue
But only develops peak power at peak rpm.
The area under the curve will always be less especially if a small compressor is used.
It does feel like a N/A just with more power.

I like the SC feel and the way it performs over a turbo BUT i would be convinced on a Turbo if the power delivery was more like an N/A if there was a properly matched turbine.

Now to the things that have been posted that made me laugh :
"They designed an impeller specifically for this car"
Are you serious ?
The SC is just a source of compressed air. You design an impeller to give you the most.
With that and with its Tolerances measured you are given its maximum capabilities.
With that you decide which pulley to use based on the crank pulley diameter.

The power will be gradual as the rpm increase but maximum will only be at the Red Line. So unless you red line every gear all the time the SC will only ever be at half the stated max.
So if its 8 psi at red line well you will only ever be around 3-4 psi
What can and will improve the SC is the way you use the air.
A BOV for of throttle bypassing and a Waste gate so as you can get more pressure " the 8 psi " down lower and then control it all the way to red line. This will require a smaller pulley.

I live across the road literally from AVO . Ill see what it does compared to my properly installed SC and see if it does what i want. If so it will be Turbo. If it doesn't then well back on line with the SC and a Rotrex. And why Rotrex well because the Vortech is noisy as hell and just to big for the pressure they are able to pump.

The BIASED Vortech guy just needs the specs for the Vortech SC and then do the calculations for the pulley and what the engine can handle depending the modifications that have been made or is it stock.
Thats all.
If they say it can do 50,000 rpms , well you just calculate based on the crank pulley diameter the pulley to use for the SC that will yield max at red line.

If that is 8 psi well thats it YOU will only get that at red line, never any more period. Now how about using a Vortech SC that will give you 15 psi at red line. Install a WG and control maximum to 8 psi. What this will do is give you 8 psi down lower most likely around 4,000 rpm. And will net you more area under the curve.

Then if you upgrade you engine components or it is documented that the OEM can handle more you change the WG setting.

Turbo manufacturers give pressure charts , turbine diameters etc , so do SC manufacturers , well at least the ones that have the data. The SC needs to have the relevant maximum capabilities documented if not you are pissing in the wind.....

[RedRocket]

Originally Posted by MANDALAY

Both Turbo and SC ( centrifugal ) have their benefits and weaknesses.

The Turbo with the high temperatures in the bay.
The careful selection of size so as to get boost down low and still hold up top in the rpm range. Too big and there is lag
Oil lines
The aggressive build and shock to drive line components.
The off/part throttle weakness.
Restrictive on the exhaust manifold thus slowing the air out of the chamber and increasing the chance of detonation.
Just to mention a few.
But what you don't get is the smoothness of a N/A car.
With the correct turbo it can get close and will always have a lot of power under the curve

The SC Doesn't have the heat
Is always on boost so never a lag issue
But only develops peak power at peak rpm.
The area under the curve will always be less especially if a small compressor is used.
It does feel like a N/A just with more power.

I like the SC feel and the way it performs over a turbo BUT i would be convinced on a Turbo if the power delivery was more like an N/A if there was a properly matched turbine.

Now to the things that have been posted that made me laugh :
"They designed an impeller specifically for this car"
Are you serious ?
The SC is just a source of compressed air. You design an impeller to give you the most.
With that and with its Tolerances measured you are given its maximum capabilities.
With that you decide which pulley to use based on the crank pulley diameter.

The power will be gradual as the rpm increase but maximum will only be at the Red Line. So unless you red line every gear all the time the SC will only ever be at half the stated max.
So if its 8 psi at red line well you will only ever be around 3-4 psi
What can and will improve the SC is the way you use the air.
A BOV for of throttle bypassing and a Waste gate so as you can get more pressure " the 8 psi " down lower and then control it all the way to red line. This will require a smaller pulley.

I live across the road literally from AVO . Ill see what it does compared to my properly installed SC and see if it does what i want. If so it will be Turbo. If it doesn't then well back on line with the SC and a Rotrex. And why Rotrex well because the Vortech is noisy as hell and just to big for the pressure they are able to pump.

The BIASED Vortech guy just needs the specs for the Vortech SC and then do the calculations for the pulley and what the engine can handle depending the modifications that have been made or is it stock.
Thats all.
If they say it can do 50,000 rpms , well you just calculate based on the crank pulley diameter the pulley to use for the SC that will yield max at red line.

If that is 8 psi well thats it YOU will only get that at red line, never any more period. Now how about using a Vortech SC that will give you 15 psi at red line. Install a WG and control maximum to 8 psi. What this will do is give you 8 psi down lower most likely around 4,000 rpm. And will net you more area under the curve.

Then if you upgrade you engine components or it is documented that the OEM can handle more you change the WG setting.

Turbo manufacturers give pressure charts , turbine diameters etc , so do SC manufacturers , well at least the ones that have the data. The SC needs to have the relevant maximum capabilities documented if not you are pissing in the wind.....

I totally agree.. The wastegate is a must, otherwise your really not enjoying your toys as much as you should...

[FreshFRS]

Originally Posted by MANDALAY

Both Turbo and SC ( centrifugal ) have their benefits and weaknesses.

The Turbo with the high temperatures in the bay.
The careful selection of size so as to get boost down low and still hold up top in the rpm range. Too big and there is lag
Oil lines
The aggressive build and shock to drive line components.
The off/part throttle weakness.
Restrictive on the exhaust manifold thus slowing the air out of the chamber and increasing the chance of detonation.
Just to mention a few.
But what you don't get is the smoothness of a N/A car.
With the correct turbo it can get close and will always have a lot of power under the curve

The SC Doesn't have the heat
Is always on boost so never a lag issue
But only develops peak power at peak rpm.
The area under the curve will always be less especially if a small compressor is used.
It does feel like a N/A just with more power.

I like the SC feel and the way it performs over a turbo BUT i would be convinced on a Turbo if the power delivery was more like an N/A if there was a properly matched turbine.

Now to the things that have been posted that made me laugh :
"They designed an impeller specifically for this car"
Are you serious ?
The SC is just a source of compressed air. You design an impeller to give you the most.
With that and with its Tolerances measured you are given its maximum capabilities.
With that you decide which pulley to use based on the crank pulley diameter.

The power will be gradual as the rpm increase but maximum will only be at the Red Line. So unless you red line every gear all the time the SC will only ever be at half the stated max.
So if its 8 psi at red line well you will only ever be around 3-4 psi
What can and will improve the SC is the way you use the air.
A BOV for of throttle bypassing and a Waste gate so as you can get more pressure " the 8 psi " down lower and then control it all the way to red line. This will require a smaller pulley.

I live across the road literally from AVO . Ill see what it does compared to my properly installed SC and see if it does what i want. If so it will be Turbo. If it doesn't then well back on line with the SC and a Rotrex. And why Rotrex well because the Vortech is noisy as hell and just to big for the pressure they are able to pump.

The BIASED Vortech guy just needs the specs for the Vortech SC and then do the calculations for the pulley and what the engine can handle depending the modifications that have been made or is it stock.
Thats all.
If they say it can do 50,000 rpms , well you just calculate based on the crank pulley diameter the pulley to use for the SC that will yield max at red line.

If that is 8 psi well thats it YOU will only get that at red line, never any more period. Now how about using a Vortech SC that will give you 15 psi at red line. Install a WG and control maximum to 8 psi. What this will do is give you 8 psi down lower most likely around 4,000 rpm. And will net you more area under the curve.

Then if you upgrade you engine components or it is documented that the OEM can handle more you change the WG setting.

Turbo manufacturers give pressure charts , turbine diameters etc , so do SC manufacturers , well at least the ones that have the data. The SC needs to have the relevant maximum capabilities documented if not you are pissing in the wind.....

you forgot postive displcement SC these get near full boost under load from say 2000-7400 giving great area under the curve and a much more N/A like power-band.

[drifter]

Originally Posted by MANDALAY

Both Turbo and SC ( centrifugal ) have their benefits and weaknesses.



I live across the road literally from AVO . Ill see what it does compared to my properly installed SC and see if it does what i want. If so it will be Turbo. If it doesn't then well back on line with the SC and a Rotrex. And why Rotrex well because the Vortech is noisy as hell and just to big for the pressure they are able to pump.




If that is 8 psi well thats it YOU will only get that at red line, never any more period. Now how about using a Vortech SC that will give you 15 psi at red line. Install a WG and control maximum to 8 psi. What this will do is give you 8 psi down lower most likely around 4,000 rpm. And will net you more area under the curve.

T.

I, and I"m sure others, look forward to you checking this out and reporting back to us, that would be appreciated.

As far as the suggestion for 15 psi: Wouldn't this scenario require more supporting mods to justify the continual boost and also put faster wear and tear on the motor?

I personally don't mind a boost at only higher rpms. What i'm looking for is to have a little more power at hand for when I occasionally want to jump on it, or to take to the track once in a while. However, if this is going to be just as safe at 15 psi because of the WG, I suppose I wouldn't mind the extra low-end power either.

Also, have to decide if the minimal power of a SC is worth paying 1/5 the cost you paid for your car.

[MANDALAY]

Originally Posted by FreshFRS

you forgot postive displcement SC these get near full boost under load from say 2000-7400 giving great area under the curve and a much more N/A like power-band.

Yes agree, just that most run out of steam.

And adding an intercooler is a must.

Even TRD can get it wrong, the Aussie Avalon was what you would call a diaster for Toyota with sales suspended then a pull out

[FreshFRS]

Originally Posted by MANDALAY

Yes agree, just that most run out of steam.

And adding an intercooler is a must.

Even TRD can get it wrong, the Aussie Avalon was what you would call a diaster for Toyota with sales suspended then a pull out

they only run out of steam if it is slightly too small or the compressor map is ill matched to the engine. intercoolers should be used with both SC anyways and no way i would buy trd. i'll develop my own manifold if necessary.

[MANDALAY]

Originally Posted by drifter

I, and I"m sure others, look forward to you checking this out and reporting back to us, that would be appreciated.

As far as the suggestion for 15 psi: Wouldn't this scenario require more supporting mods to justify the continual boost and also put faster wear and tear on the motor?

I personally don't mind a boost at only higher rpms. What i'm looking for is to have a little more power at hand for when I occasionally want to jump on it, or to take to the track once in a while. However, if this is going to be just as safe at 15 psi because of the WG, I suppose I wouldn't mind the extra low-end power either.

Also, have to decide if the minimal power of a SC is worth paying 1/5 the cost you paid for your car.

OK here is my 2 cents on the subject. On MR2 i have literally spend mega bucks that i could have bought 3 86's. I am not affiliated with any brand at all and dont profit at all.
A 86 will be my next company car.
What i do have is a MR2 SW20. I am so left field than any other SW20 owner. The engine is a limited one with VVTi that was only available in Japan. It loves to rev and has the same power as an 86 200 Hp.
I didnt go Turbo for these reasons
Heat
Turbo removes the feel of a free reving N/A
Part throttle responce
That lag and on/off feeling
Now many say their turbo doesnt do that well i have never seen one that didnt do the above UNLESS OEM and that is the key.
Kits are made to be as cheap as possible to sell items and i dont believe there is much work not necessarily on the kit itself but the Tune
There are cheap and really expensive aftermarket ECU's out there . Mine is a MoTec and total price has been half the price of a 86.
For one moment lets look at the AVO or any other Turbo kit , sure the design might look good and they will sell you the kit based on some beautiful dyno plot. You install the kit and after 2 weeks you wish you went back because of the crap idle,responce , issues with heat etc. They will say its the tune.
A kit is really worth anything if a stand alone ECU is included and properly tuned.

Now if it is a low powered install they could be using the OEM ECU well thats great until the poor little MAF doesnt know what to do. See our cars have a team, really big team in the back doors of Toyota doing all this. Do you honestly believe that some tuner with 5 hrs of tuning can do this ? No, so a real tune could cost $1000,s which blows the price that little addition whether it be Turbo or SC.

Which leeds me to another point Ild ever buy a kit ONLY if it included the ECU. Dearer yes but at least it has the work done.
I would drive or even catch a plane and see and drive the car and confirm the kit.
This will pay off in the long run.

Centrifugal
With a SC the power is MUCH more pedictable. Its just a compressor. It has a limit in what it can blow based on the mechanical factory set limits.
Lets say the shaft can spin 120,000 rpm , you set the pulley calculated on the crank pulley.
see this calculation

http://www.forestryforum.com/members...pulleycalc.htm

Baed on a crank pulley of 135 , 120,000 rpm limit and 7,600 red line the SC pulley will be 85 mm.
That is the maximum, so at 7,600 you will get the most psi, what it is will be determined by the size of the SC.

These are the figures that anyone selling a SC should give, period.
Vortech give these ?
If so calculate it yourself. So is the SC and pulleys at their optimal which are provided with the kit ?
So they say and calculte they are if its 8 psi well there you go you are done BUT at 4,000 rpm you will have only 3-4 psi. Worth it ?
Now lets look at another system when the pulleys are optimized and it blows 15 psi.
Well all you do is put a WG and bleed of the pressure you dont want. In this system you will have an extra 3 psi at idle.

Then and maybe IF the engine can handle a bit more or you build the bottom end you turn up the boost.

This is what i lave gone thru with my build , expensive YES but guess what someone can have a kit like mine on their SW20 at 1/10 th of the price since i did all the work......

What im saying is if the SC kit hasnt done all this work or Turbo for that matter, you cant drive a car they have done stay away from it. You want to drive your car NOT HAVE PROBLEMS because of an incomplete kit.
Will higher pressure ware out the engine faster , well yes in a way but a kit not tested correctly will cause a lot of frustration and could damage the engine.

[MANDALAY]

Originally Posted by FreshFRS

they only run out of steam if it is slightly too small or the compressor map is ill matched to the engine. intercoolers should be used with both SC anyways and no way i would buy trd. i'll develop my own manifold if necessary.

I live in Australia ill probably see Bullet. They know me ( hey they are the Rotrex distributors ) and ill take the 86 for a spin and see if it suits me.

Every FI should have an Intercooler and make sure again its part of the kit and tested. Ask for IAT's and look at logs.

What you are wanting is the best for your car and knowing exactly what you are getting. Lining their pockets for a theoretical responce without data will make them rich ( thats why they are doing it , to sell ) but you will be more out of pocket.

[drifter]

I really hope this thread continues. It seems that others are so sold on a particular method in other threads that they blow a fuse if anything is questioned, or, claim it's off topic if it's not in favor of what they want.

[A5D5TRYR]

Originally Posted by drifter

I really hope this thread continues. It seems that others are so sold on a particular method in other threads that they blow a fuse if anything is questioned, or, claim it's off topic if it's not in favor of what they want.

I agree. I've been enjoying this thread. As much as some people seem to take the decision a little more personally than others it does bring out a number of good points about the benefits of one over the other.

Personally when I started reading these forums months ago I was thinking small turbo for sure. I like the availability of boost (and thus torque) at the lower end and the feel of a turbo spooling is pretty awesome. But at the same time the wait for that spool can be frustrating. Also, turbo engines tend to be much harder on engine oil and the exhaust temps are higher. I think these things tend to be the reasons why SC's have more of a reputation for being more reliable and easier on the engine. Then again it might have something to do with how easy it can be to just up the boost on a turbo application and start detonating. This potentially leads to a lot more blown engines on turbos as opposed to SC's and artificially making all turbos look less reliable even though a properly set up and tuned turbo may in fact have comparable reliability. This is all just conjecture on my part and I have no data to back any of this up. Just throwing out my thoughts.

[Coheed]

I really like the AVO setup, but the fact it removes the factory cats pretty much removes it from my list. I love the idea of the mechanical scavenge pump. And I expect this part will be made separate for purchase down the road.

My favorite kit so far has been the AP kit. Simple. It does use an electric scavenge pump, which I'm not thrilled about. But a GTX2863r would be very responsive, and make just over 300whp on 10psi. With supporting mods this turbo could made over 300whp on 7-8psi and 320-340whp on 10psi. The disco potato coined the term lagless turbo. It spools very quickly and 4000rpm sees a nice surge.

But on similar boost levels, the power delivery of the AP kit and the vortech are somewhat similar. There is no unpredictable or uncontrollable surge of power with a turbo on low psi.

I had a 6262 on my last project car. And I was super happy with the power and response of that turbo. 360whp on 10psi was just incredible, and very fast! But the turbo wasn't happy until 5000rpm, so it really wanted to be revved to 8500-9000. Never felt stressed either. SR20VE FTW.

I would like the same kind of response, but lower boost threshold. My previous experiences with the GT2860rs have been fantastic! The turbo is very lively on the SR20, spools hard and responds quickly. Even low boost feels great, and you don't have to really push the turbo in order to get a lot from it.

My preference for a kit would be the AP kit with the AVO scavenge pump for reliability. GTX2863r on 7psi until clutch and injectors get upgraded. The AP kit keeps the turbo low, and it keeps the cats. The only real downside with the kit is the scavenge pump.

I like the innovate kit as well, but I have doubts the setup will get anywhere close to 300whp.

the Vortech kit looks great. Very simple. Should be very reliable. But the drag of the charger all the time isn't something I've experienced on any of my cars, seeing as how I'm a turbo guy. But I do like the kit, and the powerband is very smooth. I just wish it cured the torque dip and provided a little bit of a bump in power on the low-end. I'm sure on 10psi it's a riot though!

It's great to have to be bouncing back and forth between options for a kit though. With the Sentra I built everything for it, but a kit is a much easier and less time-consuming.

[A5D5TRYR]

Originally Posted by Coheed

the Vortech kit looks great. Very simple. Should be very reliable. .... I just wish it cured the torque dip and provided a little bit of a bump in power on the low-end. I'm sure on 10psi it's a riot though!

I thought the vortech kit did cure the torque dip. I seem to recall the early dyno's that Perrin posted in their build thread showing the torque about stock at 2000 or 2500 and then steadily separating from there as the revs climb but over the torque dip the torque didn't drop with it and just continued on it's linear increase. I could be wrong but I thought I remembered the torque dip being gone. And this was prior to all the tweaks and such so it wasn't a final tune for it.

Edit: Found it in post 486 of their thread and I'm wrong. The torque dip is still kind of there and impedes the upward trend of the torque but it isn't near as pronounced.

[gmookher]

one of the problems with the solutions that mount on top of the manifold is you'll never get a strutbar in there. Its nice to know the SC kit will not interfere with a strutbar and also keeps the heat where it belongs. It was nice to to order the GC strutbar, and know it will fit!

[drifter]

Originally Posted by Coheed

I really like the AVO setup, but the fact it removes the factory cats pretty much removes it from my list. .

But, as Sportsguy stated, are you sure the other set-ups like Vortechs will pass emitions? The idea behind the AVO was simplicity and stealth, eventhough it deletes one of the cats.

So, for me, the best FI system out there for the money is worthless to me if I"m going to get it trouble or issued a fine because I live in CA.