Turboing the 4AGE (rough draft)

[yoshimitsuspeed]

If you want to run more boost down the road I would suggest just going turbo now. Otherwise you will reach the limits of the SC, you will be blowing massively hot air and need to fork out money for a whole new setup and just bin all the work you put into supercharging it.

As for doing it on the stock ECU. I believe it should be possible to run some boost on it with mild mods. I have never heard of anyone doing it so you would be diving into uncharted territory.
You would have to find out what the MAP sensor is. If it's a 1 bar you will max it out with almost no boost. If say it's a 1.5 bar then you could run half a bar with the ECU still being able to see that. Doesn't mean you wouldn't run into other issues.
I am running 7 PSI on my stock internaled blacktop but I am doing that on a GZE ECU which presumably has softer timing. If you ran into detonation you might be able to just back the dizzy timing off a little bit or maybe not.

The one thing I can tell you for sure. If I had the time and money I would totally do it. I wouldn't even think about doing it without a wideband, pyrometer, and a good and proven knock monitoring system.
IMO one of the best things to do would be to get all that stuff installed then start getting familiar with it.
Next I wold throw in half a tank of mid grade fuel and start monitoring for knock. AFRs and EGTs shouldn't change much at this point. Keep lowering the octane and keep monitoring the results. If you start to get a little knock back the timing off a couple degrees and see if it goes away. Backing the timing off is when you need to start monitoring EGTs. It is effectively letting more heat escape and will increase the chances of burning valve.
If retarding the timing gets rid of the knock keep dropping the octane till you have it running on basic regular. If you can get your octane around 5 points lower than your premium then I expect on premium you should be able to get it to handle 4 PSI pretty easy as long as the ECU can see it and fuel for it.
Since it's a MAP car you could fashion a popoff valve that would popoff at close to zero PSI then you could slowly start turning it up.

One other thing I just remembered and I always forget this when talking about supercharging a 20v is that you will want the throttlebody before the supercharger. This makes it a huge undertaking.

[SCLEVIN]

Thanks for the info but i now have a few more questions?
Do you have adjustable pulleys fitted to your blacktop cause surely the GZE ECU doesn't control the VVT.
Why do i need a throttle body before the SC? Turbos don't.
Would fitting a turbo map sensor work? MR2 or Starlet turbo map sensors are hard to find and expensive. Lots of cheaper RAV 4 sensors around but they might be from turbo diesels. Would they still work? They are 5v.
I'll run through the set up i was thinking. M45 SC running off the power steering and aircon pulley inplace of the aircon pump with a Mini Cooper S supercharger bleed valve witch is open at tick over and low throttle. Then closes when you hit the throttle. A adjustable blow off valve fitted to control boost. Front mounted intercooler and tubing.
I am hoping that once i do go with forged internals stand alone ECU bigger injectors and all the other supporting mods. With custom pulleys made i will be able to get at least 12psi out of this SC. Maybe even as high as 14psi. Which should give it a pretty good HP figure. Then if i do get board with that then i will go with a turbo set up.
As im running the SC like a turbo then all i would need to do to go turbo is remove SC fit turbo manifold and downpipe plum in turbo oil lines ree rought the intercooler tubing a bit and its done.
Also heres that page about map sensors on the old forum. http://forums.club4ag.com/zerothread?id=2384

[SCLEVIN]

Sorry i ment Mini Cooper S Bypass Valve not Bleed Valve. DERR

[yoshimitsuspeed]

I don't have adjustable pulleys. I firmly believe in keeping the VVT as long as possible. Unfortunately you are right, the GZE ECU cannot control the VVT. I currently have it wired to the SC relay so basically I can run it disconnected for better low end power or connected for better top end. I looked at installing an RPM window switch to more closely emulate the stock activation but I decided to just upgrade to MS3. The sad truth is that after starting this business I haven't had the time or money to finish that and my car spends more time on jack stands for R&D than it does being a usable drivable car.

Superchargers and turbos are completely different animals when it comes to throttle input.
With a turbo it cannot make boost if there is not enough exhaust gas to spool the turbo. Letting off the gas causes the turbo to loose all it's drive energy. A SC on the other hand is directly linked to the motor. With a TB after the SC the SC is getting atmospheric air all the time. If you let off the gas the SC will still be trying to pump a fixed volume of air through the system. If you have an ABV then if you let off the gas it should try to bypass that air but you would need a massive ABV to bypass all the air. The problem really comes in partial throttle control. You step on the gas a little bit and the ABV closes and the SC is going to try to deliver x amount of air no matter what your throttle position. So if you are at 20% throttle the SC will try to deliver just as much air as it would at WOT. It doesn't care the throttle is only partially open. This mean the throttle will be a restriction and the pressure before it will be insanely high. The pressure after it will be very hard to control. People have tried this setup before and all say that it's like turning your throttle into an on off switch. There is no modulation. It's either on or off.

MAP sensors are pretty simple. There is voltage range and absolute pressure range. So theoretically you could use any MAP that has the same voltage range and the right pressure range but if you change the pressure range you basically trick the ECU into thinking things are other than they are. If you do this you will need to compensate other things like injectors to make it all balance out. This is a very seat of the pants, play it till you make it kind of theory. Yes in theory it should be able to work if done right but it will take some work.

For a supercharger you need to calculate the amount of air the SC moves, it's VE and efficiency vs how much air the motor uses including it's VE. I would have to do some math to say if the setup you propose would even make boost then try to calculate how much.

IMO spending money on expensive forged internals and making boost with an old inefficient supercharger is going about things backwards.
Yes an Eaton M series compressor could make crazy high boost on a small displacement motor but you have to look at efficiency maps. Superchargers are horribly inefficient. At 55% efficiency and 14 PSI an M45 might be at 315f intake temps but on the ideal turbo you might be able to run 22 PSI at that same 315F. At 14 PSI a more ideal turbo could be closer to 248f. This means you can run more boost, more timing and more compression because the whole system is so much more efficient.

[SCLEVIN]

Hmm more investigating to do i think. I did go and see a tuners last week about getting a standalone fitting and he recommended the Megasquirt 2 v3. Not as good as MS3 but should be good enough. Said he could get it build it fit it and all the other bits required to make it run distributorless ignition etc and tune it for about £1000. Maybe i should just get that done first and go from there.

[Rogue-AE95]

Knock monitor
Running boost on an NA smallport, silvertop or blacktop with stock internals a knock sensor will be all the more vital due to the very high compression that they run. I would not consider those to be very good beginner builds due to the very narrow margin for error you will have before something pops.
I call it a gauge out of simplicity but there are a number of options from DIY detcans at the $20-$50 range, knock lights in the $150-$250 range all the way up to the J&S saeguard which is able to actually pull timing to save your motor but you do have to pay for it. Finding what is the right balance of cost to security will be a choice for you to make.

On a largeport NA turbo I would highly recommend this even for a 6-8 PSI build. I would say it's essential for anything over that.
For the SP or 20Vs I would say it's essential before you throw any positive air pressure at them.


Last is a pyrometer. Again if you are doing a GZE longblock with low boost and a Conservative tune this is not a very vital gauge. The more you plan to push your tune the more important it becomes.
A pyrometer is the most important with the high compression builds because retarding timing leads to higher EGTs. Higher EGTs lead to pistons and valves melting. In a high compression build you may have to retard the timing to keep the engine from knocking. As you do this you need to monitor your EGTs to make sure you don't start melting things.

On a turbo SP or 20v build I would consider this vital for any level of boost.

Question about this, and putting a turbo on a stock smallport. Would something like the MegaSquirt 3 cover these sensors/gauges? I was thinking about building a mostly stock smallport, then fitting it with a turbo after driving it around. Alternately I could have the engine rebuilt again (or at least checked) and use the 8.9:1 pistons I have.

I was curious though what kind of power you can push out of a stock smallport with a turbo. And if that would be worth the trouble (hi-comp, coated cast pistons and less boost) vs swapping out the pistons for the GZE smallport pistons (lo-comp, coated forged pistons and more boost).

[Rogue-AE95]

^ Anyone?

My main reason for bothering with building a mostly stock smallport (without boosting it at first) is that my drivetrain is in need of a LOT of work. I can't throw 200-300 HP at it or something will explode. I'm sure it can handle a SP's tame 125 HP or whatever it actually is. I need something better than the current 4A-FE for the short term, though!

[yoshimitsuspeed]

160 to 180 WHP should be pretty doable on an all stock SP. The cams would be the biggest thing holding it back.
With some cams and good tuning well over 200 should be doable and reliable.
Just gotta monitor real close for detonation.

[Rogue-AE95]

Thanks. On that note, what cams would benefit a hi-comp turbo build? Poncams? Pretty much any aftermarket cam for an NA build, or specialty cams for turbo? I don't think I've read much about the latter.

I'm guessing the early bigport cams won't make much difference. I had picked up a set to use for my smallport rebuild.

[yoshimitsuspeed]

Thanks. On that note, what cams would benefit a hi-comp turbo build? Poncams? Pretty much any aftermarket cam for an NA build, or specialty cams for turbo? I don't think I've read much about the latter.

I'm guessing the early bigport cams won't make much difference. I had picked up a set to use for my smallport rebuild.

Yeah early cams will not make a big difference.

Turbo cam design is a little different. Generally a lot more lift to duration ratio.
I think the poncams would be pretty dang good but I do think something like a Kelford 193-T or TED turbo cam would be a little better. Whether it's going to be enough better to justify the extra cost is something you need to decide on a case by case basis.

[Rogue-AE95]

I thought I've heard that before, about higher lift but less duration for a turbo build. After I posted that, I did some digging and found this old topic:

http://forums.club4ag.com/zerothread?id ... 485#741485

Using a stock smallport head including the valvetrain... those are some pretty impressive numbers. I might add the early bigport cams that I picked up a while back to my pile of 4A-GE parts that I'll be selling soon. I can't even remember why I bought a set in the first place. Probably because I thought the little extra lift was better than the smallport's cams.

[yoshimitsuspeed]

That is impressive if it's true. Not saying it's not but it is on the outer fringe of plausible. If so then it just goes to show how hard it is to put a number on how much boost a certain setup can run or how much power a certain setup can make.
Honestly to me more surprising than making that kind of power on the stock pistons is doing it on the stock cams. The combination of stock pistons and stock cams running that kind of boost and making that kind of power (at least on pump gas which he doesn't seem to specifically clarify) is a little hard to believe.

[Rogue-AE95]

I'm pretty sure he was using a smallport GZE, so it would be the 8.9:1 pistons, not the 10.3:1 pistons. But the SP GZE would have the same cams as an NA SP.

There's also his custom intakes, which I'm sure helped. A friend of mine who doesn't know much about Toyotas (but does know a lot about other engines like the Honda B series) questioned why I would bother using the 4A-GE throttle body. He didn't like the design of the SP intake or that tiny TB. But I'm sure they can still be used to bring about respectable power.

[yoshimitsuspeed]

I'm pretty sure he was using a smallport GZE, so it would be the 8.9:1 pistons, not the 10.3:1 pistons. But the SP GZE would have the same cams as an NA SP.

There's also his custom intakes, which I'm sure helped. A friend of mine who doesn't know much about Toyotas (but does know a lot about other engines like the Honda B series) questioned why I would bother using the 4A-GE throttle body. He didn't like the design of the SP intake or that tiny TB. But I'm sure they can still be used to bring about respectable power.

SP GZE didn't even occur to me but that would make a lot more sense.

I don't mean to sound insensitive but it doesn't sound like your friend knows much about induction theory or fluid dynamics.
First of all the NA 4AGE TB is the same size as almost all gens of 3SGTE. People make crazy numbers on them with the stock TB.
Second. The Stock TB is oversized for the stock 4AGE.
Third. Boost increases density and not velocity. This means that if the TB is suitable for the motor in NA form it's suitable for the same motor boosted.
Things like cams and increased RPM that increase airflow at the same pressure IE increase velocity will eventually need bigger piping. Throw some 280 cams in a 4AGE, up the redline to 8500 and you might start benefiting from a bigger TB and bigger runners be it NA or boosted.

[wattsupbr86]

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