Force Induction : Any Options for 4AGs?

[-e f i n i-]

Sorry to bring up old topic again, but theres just something that i want to confirm.
In order for a centrifugal to pump efficiently, it has to spin very very fast and that is why step up gearboxes are for right? Do roots use step up gearboxes too?
But why do centrifugals have to rev up high to pump efficiently? do roots have to do so too?
and if your centrigual s/c unit supports up to 110000 rpm as stated earlier, tht means your s/c can still pump air at 10,000 rpm engine speed and wont have to worry bout your s/c overspeeding and getting choked where the air enters the speed of sound and stops moving?
are reversions are bad thing for supercharged engines?
are high cams lucrative on supercharged engines? i just know it isnt for turbocharged ones.

 

[LevinTE27]

u can use T3 turbo with .36 exhaust housing for ur 4ag, mine spool 2500rpm full boost @ 6psi on 86 run without intercooler.
around 180hp engine safe to run daily. :)
i recommend run sc for drift cos u wont get alot air to cool ur intercooler from front. sc without ic will work well..

 

[synchron]

Here is the answer to your question

1)In order for a centrifugal to pump efficiently, it has to spin very very fast and that is why step up gearboxes are for right?
YES

2)Do roots use step up gearboxes too?
NO

3)But why do centrifugals have to rev up high to pump efficiently?
Centrifugal s/c needs to certain amount of s/c RPM to make boost. It pump efficiently from low and high RPM as long as it does not rev over it's max supercharger speed.

4)do roots have to do so too?
NO, because they are pumping alot of air from the start and when the RPM get higher it begins to generate heat, so it looses a good amount of cool air. Presure of a roots charger is generated in manifold ( that is why the boost remains the same in high RPM) where the centrifugal s/c generate it pressure in the compressor housing.

5)and if your centrigual s/c unit supports up to 110000 rpm as stated earlier, tht means your s/c can still pump air at 10,000 rpm engine speed and wont have to worry bout your s/c overspeeding and getting choked where the air enters the speed of sound and stops moving?
YES, it can pump air into the engine at high rpm. The other part is that revving more than the s/c speed is also determine from the ratio of the crank pulley and the s/c pulley.

6)are reversions are bad thing for supercharged engines?
If you mean back flow, then the answer is yes. It will spoil the charger.

7)are high cams lucrative on supercharged engines? i just know it isnt for turbocharged.
Supercharger are in a different from turbocharger. The more power the engine generate the more powerful are supercharger. They are belt driven by the engine speed. You can actually run high comp piston on a s/c but the only set back is that you will need alot of fuel.

Smaller CC engine work very well with the centrifugal s/c while the roots or screw type works well with bigger CC engine. If you want to go for roots chargers might as well go for screw chargers, screw charger are more responsive, can boost more , able to go at a higher RPM.

The reasons that i choose centrifugal s/c is that they are much cheaper, able to reach a high rpm for the engine, less stress to the engine, easier installation, does not need to use intercooler. Especially the newer centrifugal s/c because they can spin faster than a turbo because of the high step-up ratio.

 

[-e f i n i-]

May I ask a few dumb questions?
Okay...
A centrifugal pulley works liike its step up gearbox too? to make a single rotation from an outside force seem like a thousand (just exaggerating, dont mind it)?

A turbocharger turbine is propelled by exhaust stream, and a centrifugal is turned by the crankshaft and its step up gearbox.
A centrifugal also needs to spin fast to pump efficiently. However, without step up, a turbocharger can be pumped nicely.
So we can deduce that exhaust stream rotates the impellor faster than directly driven from the crankshaft?

But how come centrifugals must spin fast to pump efficiently, and roots dont have to?
I was told it is the design. How does the design affect it??

 

[synchron]

A centrifugal pulley works liike its step up gearbox too? to make a single rotation from an outside force seem like a thousand (just exaggerating, dont mind it)?

I think you should read the pass thread, I have shown calculation on it.

A turbocharger turbine is propelled by exhaust stream, and a centrifugal is turned by the crankshaft and its step up gearbox.
A centrifugal also needs to spin fast to pump efficiently. However, without step up, a turbocharger can be pumped nicely.
So we can deduce that exhaust stream rotates the impellor faster than directly driven from the crankshaft?

As you can see turbo has lag in low RPM, with the step- up gear centrifugal s/c can reduce the lag time.

But how come centrifugals must spin fast to pump efficiently, and roots dont have to?
I was told it is the design. How does the design affect it??

Centrifugal and Roots are different all together even they are belt driven. I have posted the different in my last posting. At the begining the Roots chargers can pump in more air, but all the air is not compressed in the charger itself but in manifold. Until high RPM the roots tense to loose it grip because they just run out efficientcy because the Roots charger will generate alot of heat.

Centrifugal are different because they need to compress the air in the compressor housing. At high RPM the air inside the compressor housing will have a very high pressure.

It is pretty to understand, you will need to read alot. I cant really explain much myself.

 

[-e f i n i-]

Sorry for replying sooooooooo late. Was thinking of what to ask, and finally I have to gathered a lot to bombard you with :lol: I hope you dont mind.

- A Blacktop 4AGE can be supercharged while keeping its 4 throttle setup right? I mean with the plenum of course.

- Since a 20V silvertop/blacktop already makes 160/165hp stock, adding a supercharger would generate more horsepower than its 4AGZE counterpart right?
And since both share the same block, Im pretty sure 4AGZE block can be used on 20V

- Referring to post #83

7)are high cams lucrative on supercharged engines? i just know it isnt for turbocharged.
Supercharger are in a different from turbocharger. The more power the engine generate the more powerful are supercharger. They are belt driven by the engine speed. You can actually run high comp piston on a s/c but the only set back is that you will need alot of fuel.

So you mean, high cams(like those for NA) can be used on supercharged engines? But wouldnt the flowback of hot exhaust gases kill it??

- Do supercharged engine need turbotimers and boost controllers? A supercharger will just spin and spin proportionally with the engine, so the fast it spins, the more boost it will create right? Wouldnt it overboost if it doesnt have anything to control it? Like for a turbocharger's case, they have wastegates, how bout turbochargers?

- If high end power is all that matters, can we use a lower ratio step up gearbox? If the impellor's max speed is 60000rpm, can we use a step up gearbox that has a lower ratio, like 5:1, enabling us to rev up till 12000rpm of engine speed without overspeeding the impellor? As I know, the later the the peak torque comes in, the more power you can make, but unfortunately, the cams just wouldnt support that sort of RPM range.

- If we use a low mass, low inertia impellor and a lighter crankshaft, we can make more power out of the supercharger right?

- Okay, so we all know centrifugals are thermally effective, but can we still install an intercooler to make it more efficient?

 

[synchron]

Mr. Chin Lee Kun tried supercharging a 20v silvertop about 4-5 years back. The respond was not good at all. You will never idle properly if you use the 4 throttle for s/c usage. I forgot about the problem with this setup. I will ask him after he is back from Europe.

No you cant use high cams from N/A setup to be used in S/C. S/C still needs FI cams setting. The overlapping will kill it.

There is 2 type of s/c setup. First one is to setup the s/c before the throttle body. In this case you would not need to use any bypass valve. The throttle body will control the amount of air going in. This setup is being use for stock 4agze engine.

The second way is to put the s/c after the throttle body. By using this method you will have to use bypass valve. When the throttle body closes, the back flow might damage the s/c if you dont use bypass valve. This setting is similar to the turbo setup.

S/C are much easier to set because you dont need to use alot of stuff which is used in Turbochargers setup. The simpliest way to control boost by the s/c pulley and crank pulley.

Sorry to say that the step- ratio is fixed by the manufacturers.

Yes! the better the engine setup, you will gain more advantage on the s/c.

You can install a intercooler if you want. There is nothing to it. If you are boosting anything below 1 bar. I dont really recommend the usage of a intercooler ( personal opinion).

 

[-e f i n i-]

Type 1

There is 2 type of s/c setup. First one is to setup the s/c before the throttle body. In this case you would not need to use any bypass valve. The throttle body will control the amount of air going in. This setup is being use for stock 4agze engine.

VS.

Type 2

The second way is to put the s/c after the throttle body. By using this method you will have to use bypass valve. When the throttle body closes, the back flow might damage the s/c if you dont use bypass valve. This setting is similar to the turbo setup.

So which type is better? Which do you recommend?

Oh okay, so the step up is determined by the manufacturer.
But how if there are centrifugals with 60000rpm max impellor speed but a step up of 6:1? For racing applications, isn't the higher your engine revs the better, provided your settings compliment the rpm range?

Hmm? how does crank pulley and supercharger pulley limit boost?

How far would the stock GZE supercharger take us? Or is it recommended to be replaced with another supercharger unit?

Oh yeah synchron, can you please tell me how a supercharger is properly selected for an engine? Other than budget and type of application, What other factors must i consider when shopping for a supercharger?

 

[synchron]

Depend which engine u r using. If you are using 4agze then you will have to go with type 1.

Well i read book on FI called Superchargers,Turbochargers & Nitros. It is stated that small engine normally favour centrifugal s/c because of our light weight engine. 4age is a short stroke engine, meant for high rev. Centrifugal s/c is a high rev chargers compare to the roots chargers which is about 14000RPM and screw type which is 18000 RPM for a small unit.

Boost increament and limiting is just like the stock 4agze which uses the crank pulley which is the cheapest and easiest. Bigger pulley = more boost, smaller pullley= less boost. Unless you want to use the more sofiscated way like ECU control, boost controller and blow-off.

I cant really tell how far the stock s/c can go. If you are running on stock boost, it will last a few year without a problem. If you boosting the charger more than 0.8 bar then it all depends on luck. How many KM you done to the engine also count. Everything s/c have wear and tear, even aftermarket s/c.

You can select any s/c that you want. Trust me that it will all come down to the price. A normal root, centrifugal, and screw type s/c in the USA will cost in a range of 1600-2500 USD which exclude s/c pulley, drive snout, transportation, taxes, bracket fabrication and installation cost. In which after converting to RM everything should be ranging from RM10,000 to RM 15,000. Much more expensive than a turbo setup.

If you are going for ultimate performance, then you should go for screw type. I dont think they are streetable. They are non streetable because they dont have s/c clutch. I can say that they will generate more power than turbo.

I choose the German s/c because they have high RPM and high step-ratio. The next best thing is that they are the only aftermarket s/c which comes s/c clutch. The retail price for these chargers else where is atleast 2000 Euro's and the kit for BMW will cost atleast 4000 euro's.

I have made a deal with ASA to develop kits for Japanese engine by using some of their custom superchargers. I can retail them at a lower price which suites our market. They are rated at a MAX of 350 HP. They are comparable to TO4B setup.

 

[-e f i n i-]

hi synchron and guys... sorry for not replying, was pretty busy and this thread kinda died and i remembered bout it now. hope you dont mind
i have more questions ;)
hmm recently i saw some supercharger pulleys from TRD, i guess, which the site also stated the psi for the pulley. so i guess the psi stated is the maximum boost the supercharger will generate with the pulley?
so its like this pulley A with a max psi of 20. so when the sc turns till 20psi, it will stop producing extra boost?
so with this pulley tht limits boost, we dont need turbo timers and wastegates, do we?
since the name is also turbotime and not supertimer, i guess its not for superchargers huh?

i have some ideas synchron and i wanna ask you bout.
A 4 throttle with forced induction, probably a turbo, just like how RB26s are. But in your previous post, you said it doesnt idle properly? have you asked Mr Chin yet?

Is 20V good for forced induction? I think i read somewhere in this thread saying it isnt, but im actually not sure of what i read. So is it good? or would 16V smallport/bigpport be better?
I was told the AE86 4AGE came with large ports so its good for FI, what do you think?

Looking at parts availability, i also think 16V would be better as most parts i see made for 20V are mostly for NA. So what you guys think?

Also synchron, where can i get parts for GZE? What brands of parts are there for GZE? I see parts such as pistons and cams are pretty limited.

TODA has cams for 4AG. I know long duration ones cannot be used on GTE or GZE, but can i use the 288 or 272 cams made for NA 4AGs?
Thanks

 

[synchron]

I only know there is a few ITB s/c turbo charger has been installed but they could not idle properly. A stock roots with ITB will not get more power than it is now actually. No effect at all. That is all i know! You call Mr. Chin up in Sabah, Sandakan. He can tell you about it, he a pro in Toyota engines.

In term of 20v, i could not really tell if they are good for FI, I haven test it before. Since someone got 1.5 bar boost from it, he is from Kuching as well. And he did a 4 throttle 20v turbo, dunno how he does it but he is good. May be there is something to do with the management system. The only thing troubling is that, how does the valve last under high boost and RPM, the next problem is that the 20v camshafts are overlaping type of camshafts which is only good for N/A.

Well we normally go for 16v big port for FI. Mod oversize valve from 3sgte is one of them. They are close to the formula alantic specs. Performance are pretty easy to get actually, mostly depend on your budget actually. You can use s/c airflow pistons which is good for FI and it is the strongest piston in the 4a series. Camshafts can be easily obtain from KK, Sandakan, Miri and KL.

Toda camshaft are good for N/A engine because for their overlap. If you use a N/A camshafts on a FI engine then, you will not able to idle properly on low RPM because of overlaping and cannot lock the compression properly. I have seen special HKS camshafts for FI, they are called LC cams, 288 degree camshafts with atleast 9.5mm lift.

You dont need turbo timer and wastegate or even blowoff valve for S/C engine.

As a reminder 4agze engine are pretty hard to maintain because the parts are getting less and less. Problem like driveshafts, air-cond, s/c itself, clutches and it has a petrol & tyre thirst problem.

 

[-e f i n i-]

hmm synchron, u mean we use the valvetrain from 3SGTE? meaning, the springs, shims etc?
hmm camshafts for NA...
Toda has cams for 4AG, but its not stated if its for NA or FI purpose. I have seen 272 and 288 cams for 16V in their website. That can still be used on FI engines right? Seeing that u said HKS also has 288 cams for FI engines, so 288 is a suitable duration for 4AGT/ZE too?
the 272 and 288 cams from TODA for example, wouldnt cause too much of an overlap right? since most FI cars also use cams ranging from 264-272, so i do think the 272 and 288 cams TODA has to offer for 4AG are suitable.
and the 16V 272 has a lift of 9.0mm and 10.3mm and 288 has 9.0mm until 10.5mm lift.
i only know cams like 304 and 320 seriously cant be used on FI engines.
other TODA parts like cam pulleys can still be used on FI engines right?
so what do u think?

I can just get the big port 16V then swap the block for a 4AGZE, AE101 right?
hmm cant the driveshaft be used from other cars? i was also told the AE86 axle isnt that strong, so how bout using the whole drivetrain system from silvia?

oh i also wanna ask.
If without the presence or existence of dyno machines, how do u adjust cam timing? adjust it a little then bring it for a spin until it satisfies you?

 

[synchron]

You can use the valve from 3sgte not the whole valvetrain.

Toda camshafts are very wild and it will overlap. Even HKS or Toda has the same duration but the design of the lobe is diferent, closing and opening of the lobe.All cam pulley can be use, only different is the quality that is all.


Sorry, i never use a dyno machine before. Tuner in east coast dont use dyno machine.

If you boosting stock to about 1 bar , ae86 axle is sufficient enough. Not too sure about SR20 axle.

I only know if you want to change to W gearbox then you will need to use crown axle. And only recommend with high boost and RPM.

 

[-e f i n i-]

hmmm i thought valve is like the "door" for air to come in and go out only? and port is the passageway for air all the way to combustion chamber and also exhaust gas all the way to the manifold right?
so we port and polish the port, so we use bigger valves to cover it??

anyway... can u tell me more about that cams that can be obtained from KK and the other locations you mentioned in one of your previous posts? What is the lift and duration? is it pre-custom made, or can we ask them to custom make one set according to our preferred specs?

speaking bout W gearbox... hmm i see lotsa AE86s using that too...

 

[synchron]

Other than 3sgte valves you can use 7mgte valves. They are about the same as the 3sgte. Use the seat from 3sgte too.

You can get the cams from KK Ah Lun. He has the exact duration as the HKS ones. 264 and 272 with 8.35mm lift. You will have to ask him about the price. I know that Johnie Wu from Miri is using them on his Datsun 4agte.

If you find his price is too high then try calling Mr. Chin in Sandakan. I am sure that he can give you a good pricing. I remember Mr.Chin only got the 272 with 8.7mm lift. Perfect for high boost and RPM. The design is pretty close to the HKS LC camshafts.

You can order custom ones from me. All their camshafts comes from me.

U will need a fairly high horse power to pull the W gearbox. N/A or fairly stock s/c engine will not need to have W gearboxes.

 

[-e f i n i-]

hmmm is 8.7mm lift enough? i see the NA cams are using higher ones, i thought turbo 4AGs could make use of higher lifts too, or maybe tht has to do with overlapping again??

anyway i saw on club4ag website HKS has cams for GZE.
304° - 10.35mm, HKS - p/n 2202-RT037, Can be used on 4AGZE
--
this one for GZE has 10.35mm...
the others from HKS stated in the website and also in the hksusa.com has 8mm+ lift only too....

btw, how much are the cams, normally, made by the workshops in sandakan, miri, KK and mr chin's?

how about pistons??

 

[synchron]

Stock 8.0:1 pistons can be use.

You have to ask them. I do not control their selling price. It is all up to them. Lift does not make a cam overlap, it is the design of the cams lobe.

 

[-e f i n i-]

eh,... i thought cam overlapped is caused by its duration right?

 

[synchron]

2 different cams manufacturer may have 2 type of different cams design. Different camshaft manufacturer have different design.

For example HKS 272 cams and toda 272 cams looks different when you compare them.
Get what i mean. Toda camshaft are much wilder than HKS ones, on my oppinion only.

Toda have much rounder lobes than HKS or any camshafts than i know of.

Duration is also one of the reason.

 

[-e f i n i-]

oh yeah sync...
how much boost can the stock GZE pistons take?
gaskets?