http://www.20vmki.com/index1.html?section=20vswap&content=20vswap/20vfaq/20vfaq.html&view=s&q=2

 

hypothetically, if you were going to turbo either engine, and I dont just mean throw a turbo on there and hope you dont detroy the thing. I mean lower compression pistons, beefier rods and wire in a standalone system, would it be best to start of with a ST, saveing the money you would spend on a blacktop? The ST's block is thicker/more similar to a GZE according to club4ag.com's tech spec's, the only advantage the BT offers, turboing considered, according to club4ag.com, would be that it is port polished and running MAP, the TB"s are a little bigger too, but I dont think those would be used if you put some F/I through it, though I would love to hear I'm wrong about that. I'm considering swapping a 20v, and I know I will turbo it sooner than later, possibly before it even gets dropped in, and I'm torn over what motor to buy.

 

If you turbo, all you'll need to do to the st is add the lower comp gze pistons. I've heard from some that the 8:1 pistons will keep the engine non-interferance.

Don't buy a BT if you plan on turboing as you'll have to get rods as well. More money for an engine that will not suite you ultimate goals as well.

Under FI, the benefits of the blacktop disappear.

 

with 8:1, you could run SO MUCH BOOST... I'd like to think with 8:1's the valves would stay plenty far away from the piston it would be rediculous. Does anyone make forged 8:1's?

 

yeah, je and arias make them.

 

If you're talking about replacing rods and pistons and such already, then it won't matter much, as the block is identical, only the internals were diff (rods, pistons). And yes, its the same block as the GZE and every other 4age after 87. So if you de-compress it down to 8.0-1, then all you've done is built a US-spec GZE block. Might as well use that. (ok, a GZE block with oil-squirters, to be fair.)

So then its only about the head. Yes the 20v head flows well and has VVT operated cams. But right off the bat you're going to need an EMS to control VVT and boost. So custom maps all around at this party. And as far as the Blacktop running MAP? Well if you go standalone, then you have your choice of MAP or AFM or whatnot already. And actually i've always come to understand that AFM is more accurate for Forced Induction motors. And then you need to dream up a new intake manifold to attach to the throttle bodies on the 20v. The stock box is no good above a few Psi. And we haven't even gotten into the headache it would be probably to balance tuning for boost and tuning the VVT also on the dyno. Probably lots of time. Boost and VVT are at odds when it comes to timing on a motor (VVT makes big numbers by advancing timing, boost requires it be retarded down to avoid det). Of course, Nissan uses valve-timing on a factory FI motor (S14 & S15 SR20DET).

And will a 20v head on a GZE block really offer more potential than just a 16v GZE block already together? Enuf to be worth it?

Not to say your project can't be done. If you feel the desire, go for it. Just be aware of the difficulty. In fact its already been done more than once i believe. Search on here, and also check out the owners list at 20vMk1's site.

 

And will a 20v head on a GZE block really offer more potential than just a 16v GZE block already together? Enuf to be worth it?

since i have the 7 rib motor, (N/A) wouldnt i be in this boat? ive been thinking about just doing that, as i could probably save

personally the main advantage i can thing bt, and its not even completly relevant, is if it was fitted to the 6 speed

since both ways im sure are do-able, but time consuming, i think its a matter of personal taste, if i did go ST i would end up buying new cames as id rather be using more motor, and part turbo, as im a fan of turbos but not the lag that goes with them

 

Any1 know if the ST & BT heads are mechanically the same? I'm sure I've heard of some1 running an ST on BT electronics but I'm wondering if that would then make the VVT operate like the VVTi on the BT engines.

 

Both silvertop and blacktop use VVT, not VVTi.

 

Both silvertop and blacktop use VVT, not VVTi.

Whatever, they opperate differently bottom line. My question isn't what was called what. It was about mechanical differences of the Variable Valve Timing WITH-IN the head. I don't ever remember seeing different cams for each only for all 20v but go much bigger & you don't use the VVT anyway

 

IIRC, the BT advances the intake cam 30 degrees, and the ST only 15 - might want to confirm those numbers though The VVT is controlled by a simple on/off switch on both of them. It cannot vary the amount of cam advance (like for example, the Beams 3SGE, which can) hence all 20Vs have VVT, not VVT"i"

I'm running my ST on my BT's electronics and yes, the VVT works no differently than it does on the BT. The ST sounds a little different when the VVT is on due to the lesser amount of advance.

 

Do both 20v VVTs operate based on throttle position and RPM?

http://www.club4ag.com/faq and tech_pages/Tech Photos/VVT_SWITCH.gif

Club4ag has that figure only for the blacktop. That may not mean anything though...

 

The figure is right for ST, not sure about blacktop.

Funny, someone in another thread here insists that a blacktop has VVTi. Can the ppl that actually have one confirm that?

 

So if you swap over the electronics to the BT can you just throw some velocity stacks and filters on the silver top or do you still haft to run some sort of afm???

 

So if you swap over the electronics from the BT can you just throw some velocity stacks and filters on the silver top???

Yes.

 

So if you swap over the electronics to the BT can you just throw some velocity stacks and filters on the silver top or do you still haft to run some sort of afm???

Yes, but good luck getting all the blacktop electronics without the engine

 

Those ECUs & stuff gotta be somewhere. I got people in japan. I'll have them start looking

 

I see... I have just been enlightened!! :smile: Now I am about to go and purchace a silvertop and transfer the electronics cause I heard that the intake manifold box hits against the engine latch?... but oh well now I know... I can finally proceed with getting the parts and swapping a 4age 20V! :smile:

 

Which latch does it hit?

 

Supposedly the ST intake plenum hits the engine lid latch, I've heard that too, but I'll be getting a blacktop so no worries

 

Supposedly the ST intake plenum hits the engine lid latch, I've heard that too, but I'll be getting a blacktop so no worries

fit fine without hitting anything on mine. (silvertop)

 

fit fine without hitting anything on mine. (silvertop)

Same here...Although I'm still taking out the hood latch and using hood pins. That latch assembly is heavy.

 

i used to own a ST 20v with BT electronics. i think the main difference between the two VVT systems is the ST works on mainly throttle position on RPM. but the BT setup uses the MAP sensor to figure it as well, taking into account the load(VVT-i(intelligent)) or so toyota thinks, there wasnt a huge difference from what i could tell, only fun thing was crusing in any gear above a certain RPM, you could vary the throttle position and the VVT would switch on and off, and the tone of the motor would change completely, back and forth, fun stuff. another thing that is different, is the ST VVT system advances the intake cam 0-15 degrees, while the BT is 15-30. now i think this might be an actual difference in the gear itself, but i haven't taken apart either to look at them..

but from the info i've gathered, in the VVT system at least, those are the differences...

steve

 

well fellas, differences aside, at this point i'm 99.99 % sure I will be purchaseing a BT this week. I've called everyone in the S/E and finally rounded up the best deal. I'm still nervous about droppin 1000+$ on something.. but it does come with a 60 day warranty on the block and head, which from what I've found is the best you are gonna get, even better than jarco. wish me luck fellas...

 

/jealousy


What does that include for $1k? I'll probably buy from that "Anarchy Motors" on ebay that always has 20vs up. They have a blacktop complete swap for 1100+ shipping and they seem to have really good feedback. I decided it wasn't worth an extra 1k for a 6spd so I'll just be using the c56.