single turbo,TT, or supercharged

[aaronh2005]

just a quick question...

i am a huge fan of the TT supra, however more and more i am seeing single and supercharged supras. y would someone put a supercharger on a supra? also y would someone only have a single turbo? btw i am talking about the MKIVs.

thanks,

aaron

[SUPER_glu]

the answer MONEY !!!!!! i personally would take a supercharger over a turbo anyday instant boost not to mention if you want moor boost you just change ur pully. i personally own a 7mge that im going to supercharge just because of the money issue to supercharge my car all i have to do is modify the intake manifold i dont have to buy the turbo manifold then the ic then the waste gate then the down pipe then the turbo timer........see its a mony deal plus there is more to go wrong with 2 turbos then 1 big one

[projectsupramk3]

Ok get your ears ready for this one! Two turbos are not always better than one, a single larger more efficient turbo will easily outperform the two stock sequential pea shooters.
SUPER_glu, what do you mean "if you want moor boost you just change ur pully." If I want more boost I just push a single button without getting out of my seat, picking up a wrench, swapping the pulley and getting back in the car. I understand why you've been saying what you've been saying, because you don't drive a turbo so what you know is second hand, don't worry, my old daily was n/a so I know where your coming from, I've thought about SCing it many times but the HP gain and time spent isn't worth the money lost. The only reason to do it is the "ohhh and ahhh" factor. On a turbo you don't have to buy a DP, you don't have to buy an IC, you don't have to do anything. Same with a SC, if you want to truely harness the power your going to have to build or have built a custom header, since the pacesetter will be much to restrictive, you will also need a 3" header back exhaust, you will also need an IC possibly with a sprayer unless you like detonation from high intake temps, a fuel controller is a must unless you plan on going carbed. The only thing you won't need is a WG, Turbo Timer, and boost controller, you might need a BOV depending on what type of SC you use though (centrifugal or positive displacment). All in all your going to spend more money because your doing something different which is not necissarily a bad thing, more power to you if you can acomplish it, but don't think that it's going to be cheaper unless your cheaping out somewhere or your an excellent fabricator and are building everything yourself. Good luck on the project though, I'd definetly like to see pics when it's done as would everyone on SF I'm sure.

[aaronh2005]

now would twin turbos be better than a single if you stage them??? i would think so...because you would have a smaller one for low end and a larger one for high end. can you tell how exactly staging 2 turbos would work?

[Derby]

Paralel turbo's have the advantage that you can keep them small, so the compressor spins up easily. So this gives more torque a low revs...which is needed with multivalve engines. And the exhaust design is simpler and more efficient.

1 turbo or single turbosetup has the advantage that is can displace a lot of air...or high pressure. but it takes some time to get it spinning. there are all kinds of electronics needed to keep the turbolag in a acceptable range...Exhaust design is very hard and works not best...intake on the other hand is more easy to make/design.

serial turbo setup. Four words: there is nothing better...
The new bmw 535d has a serial turbo setup and i really can't wait to drive it...
there is one little turbo it gets it's exhaust gases from a big turbo (BT)...the volume of the exhaust gasses is nog enough to get the biggie spinning enough for pressure. But the small turbo (ST) spins up very fast ( low weight) and is giving pressure, not much but there is pressure. this goes to a IC and enters the intake...
This is all at low revs.

When the rpm is rising the BT begins to spin harder and is begin to pump air. The ST is spinning very fast and is getting close to the max...

At high revs the BT is spinning at most effecient rpm. The exhaust gasses are dumped into the catalyst directly now, otherwise the small turbo is getting to much of an obstruction.

This works better then a VGT. and the respons should be very fast...but i haven't driven one yet...

Derby

[MonsterMiata15]

projectsupramk3, super_glu was talking about the supercharger's ability to change between pulleys, allowing different PSI settings and variations. The diameter of the pulleys varies, so the larger diameter, the more power, theoretically. Although I have seen people try to interchange pulleys from larger superchargers, such as the Weiands which are really meant for only Hot Street or just all-out racing; not for your centrifugal supercharger...and to no avail, they now have to rebuild their engines, top to bottom because the pulley was spinning either: a) way too fast or b) way too slow...therefore you have to find your median.

As far as the whole "bang for your buck", with tons of power, go with the single turbo. However, if you're looking for alot of power, but also have the ability to spool up fairly quickly, go with the twin-turbo setup. Basically, with the twin-turbo setup, you generally use rather small turbines and housings, which allows the turbine to spool up when you mash the throttle to the floor. Single turbos, like the T88's require time to spool up...I believe that the delay between the "mashing" of the throttle and the actual spool-up is called turbo lag...I believe i've heard that called a few various names at the track, varying from many extremes...the most popular thus far..."You God d*** piece of ****ing ****!" Back to a more serious note...if you're looking for great low-end torque, and if you're a motorhead i'm sure you've heard this from when you were lying in your crib..."Build a motor for torque, and horsepower will follow." The supercharger allows the engine to produce massive amounts of power at fairly low RPMs, which make them very desireable for trucks and SUVs. I've even seen various manufacturers such as Paxton, Powerdyne, etc. make their way into this thriving sport compact market. So, it really depends on your personal preference. In my opinion, for a helluva lot of fun, go with the supercharger. There's nothing like pulling up next to a guy, mashing the throttle and listening to the whistle from the whirring belt coming from your screaming beast that's revving up to 8,000 RPMs...nothing like it.

[projectsupramk3]

Yes, trust me I know about SC's and what's needed to make them work properly, at one time I was going to SC the 7m. It's not so much a set pulley size as the speed relation to the crank speed, underdriven where the crank is turning faster than the SC, overdriven is just the opposite, it's very simple. There are many calculations and airflow charts for determining what drive % you should run for a certain engine, blower, and so on. You can use a gilmer / 8mm / 1/2" pitch belt on a centrifugal with no problem if you figure the right number of teeth to get the blower speed right. People ruin their engines that way the same as they do with turbo's, because of bad tuning or no tuning at all from just tacking on boost. As for twins, they will not spool faster than one equal sized larger turbocharger because of the simple fact your cutting the engine in half. Each smaller turbocharger is only fed by 1.5L, the only way they will build boost faster than a larger single is if all the engine's airflow is diverted to one of the two twins, a sequential setup, or diverted through another turbo like derby already said. Much to complicated and expensive to setup IMO because of the simple fact "lag" is overrated by owners who don't even have or haven't even driven a turbocharged car. If you size the turbine and all other related parts correctly to the engine you will have very little lag, unlike a T88 on a B16 that a ricer installs for the sound. Anyway the saying in the racing world is "build for HP, gear for torque" since torque is multiplied through gearing, lower gearing will make more power at the expense of speed. Of coarse it should come out the same since torque and HP are derrived from each other. There's more than one way to skin a cat.

[longlivetheZ]

Originally Posted by SUPER_glu

i personally would take a supercharger over a turbo anyday instant boost not to mention if you want moor boost you just change ur pully.

Why people think of turbos as horrid, lag ridden creatures is beyond me. A well designed and put together turbo *SYSTEM* will have NO noticable lag at all. I've actually seen a video of a turbo making boost at idle.

Plus...you have to get out and bust out the tool kit to change pullies when you want to change your S/C's boost...all I have to do is turn a knob or hit a button...all from my driver's seat.

Turbos rule, man.

[TcmaBoy]

I think you all are a bit off target. Before making a decision on what kind of forced induction to use you should consider what your usage will be. If all you want is a dyno queen or a drag car than a large single turbo will be fine. The lack of low end power due to the long spool time can be off set with a hit of nos at the launch. Keeping it over 4K RPM to maintain boost won't be a problem after that. In a street/strip or road race aplication the lack of low end torque may not be ideal. A supercharger may not be a bad idea for several reasons. The first is throttle response. Since the SC is driven by the crank boost will vary directly with engine rpm. I should mention I am refering to roots blowers not centrifugal SC. Where as with turbos a BOV is needed for when the trottle is let off. When the trottle is shut exahust gas is also cut. Eventually the turbo slows. The advantage really goes to the SC when you get back on the throttle. Since the SC is crank driven it will still be making boost. If you have been off throttle for an extended period of time, say as in traffic for a street aplication or in cornering in a road race aplication, The turbo will spin down and must be spun back up. Thus trubo lag rears its ugly head. The longer you are off throttle the more it will spin down. With newer turbos lag is minimal but still present. Also there is power band to consider. Again in a dyno/drag car high revs are not a problem. However on the road course or on the street you probably want a power curve lower in the rpm range. I personally have a 1JZ powered Supra. I aim to road race it and as such want a power band between 4K and 6K rpm. I don't want to rev the piss out of the engine for longevity reasons. On the street most of the time you will be operating between 2500 to 3500 rpm. What good is any set up that only makes power over 3500? This is where small turbos and roots blowers have a huge advantage. Turbos do have an distinct advantage in the top end. Roots blowers quickly peak and become massively inefficiant at high revs. Centrifugal blowers are another story. They are essentialy turbos with a crank driven pully They are not the best at the low end but with different gearing or pullys they can easily be tuned for your powerband. I saw a mention of electronic boost control in one of the posts. Increasing boost is easily attainable without changing pullys in a centrifugal blower application. If you have a street/strip car and don't want full boost on the street you can set up the SC for your race pressure and simply bleed off the excess with a BOV for the street. It will be loud as hell but it will work. Then silply adjust the BOV for desired boost at the track.

[projectsupramk3]

We are all a bit off target if that's what you mean, the original question was "y would someone put a supercharger on a supra? also y would someone only have a single turbo?", and it has been answered. Why are you still complaining about lag? Were talking about 2-3 seconds at the most with a big turbo waiting on full boost, then between shifts there is no lag for the most part so why do you see it as such a problem? IMO a turbocharger is much better for the streets, the setup is perfect if it makes all it's power over 3500rpm, ontop of that the power comes on and grows smoothly unlike a roots blower where it basicly just hits then dies off. If your driving in the rain you don't want 500hp when you barely push the throttle at low RPM's, where you could accidentally blip the throttle and wrap the car around a tree. Why wouldn't you need all the power at high RPM for the streets anyway, for daily driving you don't need more than 150hp to move the car along with traffic. I don't know about you but how often do you go around flooring it between stoplights like the soccer mom in the minivan beside you, where you require 500hp to get to 45mph. Whatever the case is the simple fact is that the turbocharger will always beat a supercharger, in versitility, in efficiency, in cost, almost every way possible. Good luck with competitivly racing the 1jz, got any pics of it by the way?

[TcmaBoy]

I have pics of my starting point. Nothing recent. The car is in pieces. I havn't decided on where to go with the engine yet. There aren't many tuners working with this motor. most of what I have found is based arround a T04E. A little big for me. I am aiming for a fat midrange. I was thinking maybe a pair of GT25s. Cheap and simple. I wish I had the compressor map for the CT12A. It would make it easier if I could compare different turbos to the stock ones. I am even toying with the a few other ideas. Like using a 2Jcrank in the 1J block to make a stroker. I have no clue if it will fit. I have also considered bumping compression to help the bottom and mid range. After all an engine lives a lot longer at lower revs, and I can't afford a new motor every race. Compound boost would be realy cool, but way to complex at this stage.

[TcmaBoy]

Out with the old

[TcmaBoy]

Behold the new.

[projectsupramk3]

Forget stroking the 1jz, just buy a 2jz bottom end new from toyota if you want to do that. Have you looked into upgrading the CT12A's with a 1g exhaust wheel? You'll be able to boost higher where the ceramic wheels would be flying apart. It wouldn't be much power but it would have excellent spool time, great for circuit racing. A to4e isn't what I would consider big anyway, if you size it correctly it should only have margionally more lag than a CT26 on a 7m with alot more potential. I don't think the life of the engine will be much effected by low vs. high RPM's, since you'll be racing it your going to be putting alot of stress on it regardless of the RPM, even the mighty JZ is going to give out eventually. Car looks good though, very clean. What do you plan on running in anyway? SCCA of coarse? I know the rules allow engine swaps if they came in the same car for SM/SM2 but they might like to argue it didn't come in the same car here in the US, might want to check that one out to get the details.

[TcmaBoy]

Hopefully with JDM engine swapping becoming more common the SCCA will accept it. I know that in some venues such as the Speed World Chalange they have been running forgin models of some of the cars. Either way I will find a way to run it. Even if all I can do is local auto cross. I just want to build cars that not everyone has, and what good is a soprts car if you can't go out and play? I have a few others in the planning stages such as a VW Bug with an old 911 air cooled flat 6 and maybe an old 260 or 280 Z with an RB series motor. Eventually I want to get my hands on an early 70s Skyline GTR.