Force Induction : Any Options for 4AGs?

[1298]

normality78
i was running at 12psi with my sc b4. then 10psi with my turbo...now boost up to 14psi already. hehe.

rollakid
well, yeah, sc has a very good respond due to it's activated by the vacuum thing. I donno how to explain, but instead of have to wait till certain rpm like turbo, sc will kick in at around -2 vacuum if i'm not mistaken. that means whenever u step on the pedal a little bit harder, boost will kick in, and thus more fuel...and it's not easy to control that due to the respond is too good. haha.

-e f i n i-
yep, 1GGZE uses sc14 while 4AGZE uses sc12. the 1G unit has a larger air volume thus if able to mod it into 4AG, it might be able to produce colder boost than 4AG unit. that's what i heard from other forum long time ago... :rolleyes:

 

[-e f i n i-]

What bothering me now is how far the factory SC12/14 unit can take you. like what was said, after high rev, no more power. surely some aftermarket SC units from Rotrex or Vortech or synchron's one be better right?
and turbo will also be cheaper to get more power out of it.

 

[1298]

oh well, the sc12/14 unit is quite old in technology already, and it's root type, it pulls air instead of compress it. that's y it's called or classified as a "blower", and it is least effective amongst the other types.

The Vortech sc is a centrifugal type charger, it compresses air like a turbo...that's y it's more efficient in terms of power output, but in the other hand, it will be lack of low-rpm boost.

 

[synchron]

SC 14 is great for power but it lag a little from the start because the blower is larger than sc12 and also because of its weight of the blower core, they more heavier than sc 12. SC 14 max rpm is less than 10K.

Turbo charger is the cheapest option in the market, because it is mass produce and also it has less expensive internal parts than a sc.

Centrifugal s/c is a getting it porpularity in the market. Vortechs, procharger, powerdyne and Paxton are earlier one's to come out with this centrifugal s/c but somehow their technology is old. Laggist at low rpm, only power after 3000 RPM most of the time.

The later one's are Rotrex, ASA and Novidem, as far as i know. These 3 companies produce much smaller s/c , faster and more powerful s/c. They are all European company. The respond of the s/c is as good as the roots chargers, much easier to control at low rpm.

 

[rollakid]

synchron, bigger blower displacement = lag cuz need more time to fill up the vacuum inside like having too big or long piping with the turbo?

simon,
woi.. 1 whole week didn't see you online msn liau.. where you hide ar?

 

[synchron]

A bigger blower will be more heavier to pull, end up needing more to pull the blower at start. Not too sure about the air filling inside, because the air is compress in the manifold rather than inside the blower. Which also make the air compress hotter.

Different from a centrifugal or turbo unit which compress air in the housing.

 

[rollakid]

yeah but can't deny the fact that sc14 will have overall producing more boost if put in 4ag cuz it can spin slower to produce the same amount of boost... this means its cooler right?

 

[synchron]

It is not spinning slower. Spinning is determine the pulley size. SC14 has a bigger sc pulley, that is why it is spinning slower. No doubt it can still produce more power than the sc 12.

Yes, it doe produce more power than the sc 12, but still it will never get close to the ++50hp mark. You will get 1 bar ( that is what i heard) when you install the sc 14 into a 4agze engine by using both stock pulley in crank and s/c. sc 12 is only 1.2 litter and sc 14 is 1.4 litter. Power increment will be less than 20%. Using a bigger pulley into the crank, the sc 14 will die faster, the bearing inside the sc 14 only can take 8-9k sc speed.

Installation cost will cost more 1K, SC14 does not come cheap anymore, modding bracket, pipings and fabrication work. Is it worth it for the amount of power you are getting with the money spend.

I have tried 1.2 bar and a .95 bar 4agze, not much of a differents. I doubt that the sc 12 is creating anymore even with high boost.

 

[-e f i n i-]

Time to revive a dead but informative topic.
Actually i was gonna ask you more questions on superchargers. been really curious and theres this urge to know the answer.... but after reading what you said...

Yes, it doe produce more power than the sc 12, but still it will never get close to the ++50hp mark. You will get 1 bar ( that is what i heard) when you install the sc 14 into a 4agze engine by using both stock pulley in crank and s/c. sc 12 is only 1.2 litter and sc 14 is 1.4 litter. Power increment will be less than 20%. Using a bigger pulley into the crank, the sc 14 will die faster, the bearing inside the sc 14 only can take 8-9k sc speed.

... i suddenly cringe in fear... but i'll try to quench my curiosity anyway.
So OEM Toyota superchargers really can't add more power?
Can the SC14 bearing be changed for higher SC speeds?

Supercharger pulleys doesn't control boost right? Because if it just spin and spin and spin, how does it regulate boost pressure?? But whats that pressure rating as advertised on supercharger pulleys? Like Pulley A, 15psi. What does that mean?

If you wanna squeeze every bit of power out of your supercharged engine, is it wise to use a smaller pulley? This is what I think and synchron, I'll leave you to judge whether what i have in my mind now is true. Okay here it goes, when using a smaller pulley, max boost will come in later, as the supercharger is also spinning slower.And since higher duration cams can be used on supercharged engines, and the higher the duration and lift, the later peak power will come in but usually in a larger number, if we can make the max boost come in later like say 8000 or 10000RPM, we can make more power out of it.
is my theory true? This theory is based on the combination of NA tuning but a little of forced fed tuning.
But if we make boost come in so late like in the scenario given, wouldnt it be equal to a large sized turbo response or worse?

but since u said SC14 cant take any more than 9K sc speed... erh, does 1rpm engine speed translate to 1 or higher rpm SC speed depending on the pulley size?
I forgot already but i think u told me this once, roots type doesnt require a step up gearbox as it is pumping air in faster than a centrifugal, right?

I kinda dig superchargers, but the price is a bit expensive...
like what u said last time, if i dont have RM10K in hand, i better not play SC.

Oh yeah, this is also something that is bothering me for quite awhile, say we use W55 gearbox, how bout the other drivetrain bits? rear axle and all those? can we use the whole drivetrain system from the 1G Supra models? I dont think Silvia drivetrain can be fitted... for waht reason, i dunno...

Okay enuf stupid questions for the day.
^_^

 

[synchron]

The s/c 14 bearing be change, it will a bomb first thing. Second thing the charger will still produce the same amount of hot air. It does not matter what you do to the charger,unless you mod it into a screw type.

Stock s/c always has a limitation to it. It is meant the way when it is build.

S/c pulley can only set the max amount of boost that your engine get. Pulley A 15 means that the it can only boost 15 psi with pulley A and with the charger it suppose to be.


For s/c the boost comes in the same time actually, just the amount of boost you will be getting at the same time. Example:- instead of getting 6 psi of boost in 3000 RPM, you will be getting 10 psi with a larger crank pulley.

The smaller pulley you meant is the crank pulley or the s/c pulley? There is no way the boost will be cmg in at 8000 or 10000 RPM. Our engine does not REV so high anyway, 7600 RPM is the redline. You must make clear that you are using a s/c not a turbo charger.

Roots s/c are well known for it responds not Top end power.

The engine RPM speed and the s/c RPM speed are different but they are related. The equation is the diameter of crank pulley divided by s/c pulley diameter.

Example:- 4agze oversize pulley 175mm is divided by s/c pulley diameter 124mm. You will get 1.41 ratio. At 1000 RPM engine speed the s/c will be spinning at 1410 RPM. At 2000 RPM engine speed the s/c will spinning at 2820 RPM. Do you get what i mean?

Stock s/c parts are not cheap and they rare now adays. Aftermarket part are definately expensive. As i say before it all comes down to budget. Dont expect a RM 1000 budget engine to beat the a RM 10000 budget engine.

If you are using the stock roots charger you can use the T50 gearbox since you will not be generating too much power. You can look 4.1 diff rear axle, it should not be too hard to find. W55 gearbox, 1g rear axle or silvia axle are over kill if you dont mod your until the extent.

 

[rollakid]

4.1 final diff isn't hard, but i heard it will hurt the wallet on the fuel consumtion topic..

is it posible to find a 3.9:1 final drive or 3.7:1? read from somewhere that use 3.7:1 for good fuel economy and 3.9:1 to tapau b18c vtec. :D

 

[synchron]

3.7 or the 3.9 are more suitable for the turbocharger engines. They provide more top for the car and they dont need to shift gear so often and much easier to launch the car.

S/c engine are power base on torque on low till mid range. Cant possibly use the the 4.3 diff because have shift gear very often and also it will kill the diff because of the torque produce by the charger engine.

Not pretty sure fuel economy of these rear axle.

 

[normality78]

hm.. i think for our model toyota, SC kit is quite easy to get and i think its cheaper thn turbokit. why is it SC is more expensive?

 

[synchron]

Used stock sc12 s/c are pretty to get but they are getting rare now adays.

You cant compare a new s/c, new turbo and a used s/c. They are totally a different thing.

 

[-e f i n i-]

Hmmm....
I thought when u use high cams, power will only come in at a much higer RPM range...
Cuz u see, for NA engines, the way they make a lot of power is by pushing the torque to the later range in the rpm, like based on the equation:
(Torque x RPM)/5252 = Horsepower

but then there are some 4AGEs making power in the 11000rpm, why cant our engine rev that high??
Erm sorry for not stating it very clearly. I meant Supercharger pulley. But after looking at the formula u used to calculate the ratio, i dont think my theory i made earlier can be applied anymore.
so based on your formula, crank pulley(??) diameter/sc pulley = the ratio of the spinning SC,
the bigger the diameter of the SC pulley with the crank pulley diameter still the same at for example 175mm, the slower it will spin...
hmmm, yeah i think i get the picture now.

At which power level is it recommended to use W55 so as it wont be too much of a burden for ur engine to pull it?

After much moments of deep thoughts, Im starting to believe that a correctly sized modern turbocharger is better. besides, there are turbocharged formula one engines in the 80s if im not mistaken running 1500HP on a 1.5litre engine.

Hey i also wanna ask, if we smoothen the sharp edges on the crankshaft, i presume its called counterweight, how much can we increase the durability of the crankshaft??
Since smoothening or rounding the sharp edges helps prevent cracks and all sorts of high pressure and force caused damages on it, to focus on the small-area counterweight edges.

 

[synchron]

Yes and no for the high cams functions, it comes down to how you tune the cams actually.

The only 4age making power at 11,000 RPM in Malaysia that I have seen is turbochargered.

W55 gearbox is more suitable when you have alot of power to the engine like 300 HP and above.

Not too sure about F1 engine in the 80's. Cant answer u much on turbo stuff either because i dont have much knowleadge on them.

I have never done lightening of the crankshafts and or counter weight balancing before. So i cant answer this question as well.

 

[-e f i n i-]

wow turbo 4AGE running 11000rpm?? how does it perform? what turbo is it running on?
hey idling when using high cams is set on the ECU or does the engine itself adjusts the idling by its self after installation?

 

[synchron]

4agte turbo runs more than 10k in the East coast. I think there is more than 3-5 ae86 in the East Coast which runs their engine more than 10k RPM. Most of them more than 400HP. TO4E turbo are most common and widely use in the 4agte.

Not sure on what u were saying on the last few sentences regarding cams and ECU.

 

[rollakid]

simon, about having smaller sc pulley to make sc spin slower so engine can rev faster without hitting the sc's rpm limit, seems like it will only be the case of centrifugal s/c. root type blower make power at low end, it reach its max boost even before it ran out of boost, so fundamentally it is not design for high rpm power.

i can't tell the power just by thinking about the theories, have to put the cars on the treadmill to dyno it :D

talk about root type charger, there's one design for mustang's v8, as you can see from the chart, the power come mostly at 2-3.5k, above that the torque drop like mad... and mustang revs to 5k+

 

[-e f i n i-]

hmm T04E quite expensive...
can a turbo cam support that RPM range? i mean like 10K rpm.... i thought normally those 272 or 264 cams normally make power up to a certain stage and then performance drop as you go above the higher RPM range. I might be wrong though.
Hmm what i meant was...
U see, when you install high cams, idling will surely need to be high to prevent engine stall right? say a car with 302 cams and 2000RPM idling....
that 2000RPM idle, is it auto-set by the ECU as in self-adjustment after camshaft installation or you have to set it yourself on a programmable ECU?

wah chris...
okay lor, so turbocharger definitely sounds better as a long term investment for power.