4ag quads

[Pies]

need to know a ouple of things.

1. differences between silvertop and blacktop throttle bodies?

2. can the silvertop throttle bodies be used in a map sensored setup?

thanks

[big_boy]

45mm & 49 or 50mm

yes but from memory most people have trouble getting a stedy reading at idle

[Pies]

and finally, will blacktop bodies bolt on to a silvertop manifold?

[fivebob]

45mm & 49 or 50mm

Are you sure about that, I thought they were 43 & 45mm

[Pies]

i heard 38 and 39 lol

im not overly worried about the size, more the fact that i will be able to seperate them to run on a 6 cyl engine. and also use them in a map sensored environment

[Jebus]

Yep 43 & 45

[Crampy]

The Silvertops are 43mm and the Blacktops are 45mm. The measurements are the butterfly size. They both have a bit of taper in them.

You can bore the Blacktop quads out to a 50mm butterfly, but I would imagine it wouldn't have any taper after that.

As for bolting the Blacktop throttles to a Silvertop manifold, yes you can. BUT. The ports are way different, so you'd need to get it matched. The throttle linkages are set up differently on each of them too.

The Blacktops have a vacuum accumulator, as they are MAP sensored from factory, this gives it a smoother vacuum reading at idle and high vacuum driving.
You can use Silvertop quads with MAP sensor, but it's best to make up a vacuum accumulator for them as well. Don't take the MAP sensor vacuum from a single runner, that is bad!!! OK....

[Pies]

The Silvertops are 43mm and the Blacktops are 45mm. The measurements are the butterfly size. They both have a bit of taper in them.

You can bore the Blacktop quads out to a 50mm butterfly, but I would imagine it wouldn't have any taper after that.

As for bolting the Blacktop throttles to a Silvertop manifold, yes you can. BUT. The ports are way different, so you'd need to get it matched. The throttle linkages are set up differently on each of them too.

The Blacktops have a vacuum accumulator, as they are MAP sensored from factory, this gives it a smoother vacuum reading at idle and high vacuum driving.
You can use Silvertop quads with MAP sensor, but it's best to make up a vacuum accumulator for them as well. Don't take the MAP sensor vacuum from a single runner, that is bad!!! OK....

cheers dude! exactly what i was after

[RomanV]

So jsut for clarification, what engine are you going to run these with, and what computer are you going to run it with?

You know that you cant run ITBs with a stock computer, right?

[soopachargen]

just for the sake of arguing there's a guy on mr20c that claims to be running quads on a 5sfe with standard computer...

[strx7]

with an AFM set up, there is no real reason why quads couldn't work with a factory ecu.

[RomanV]

What about TPS signal? as you've effectively increased your throttle body area massively... 5% open throttle is a lot different between the two, in terms of cross sectional area.

[Crampy]

What about TPS signal? as you've effectively increased your throttle body area massively... 5% open throttle is a lot different between the two, in terms of cross sectional area.

I agree. Having four 45mm throttle is equivalent to a single 90mm throttle, area-wise. (although there are also other factors which will change the tune as well.)

[soopachargen]

i thought (read thought) that with ITBs that its different as you only have one throttle being sucked through at a time???

[Crampy]

i thought (read thought) that with ITBs that its different as you only have one throttle being sucked through at a time???

Yep that's right, that's why I stated it was area wise, it is equivalent to a single 90mm throttle.

[soopachargen]

whats the maths/logic behind that?? (my brain is hibernating)

[Pies]

will be using aftermarket ecu. there is no reason why you cant convert to quads on standard computer. you may need to add a few bits in somewhere in the loom to trick the ecu into thinking its running one. but its do-able.

im opting to use a link/similar purely to accomadate the cams and fueling aswell.

[spencer]

for what your doing dude get what ever throttles are available and just tap into each runner on the original manifold to get your map it'll be fine. how big are your cams going to be?? too big and the map isnt used for WOT anyway.

[iainous]

I've put 20v itb's on an N/A 2JZ, it's not running yet but have got a link G3 to run it, have spoken with several different tuners and they have all said they tune using TPS on itb's so no MAP, they say its hard to get a stable MAP reading with itb's and that cams make it even harder

[strx7]

What about TPS signal? as you've effectively increased your throttle body area massively... 5% open throttle is a lot different between the two, in terms of cross sectional area.

That isn't quite how it works though. Think about this. a GTiR SR20DET runs 4 x 45mm throttle bodies, 1 in each runner. Yet most other 2 Litre turbo engines runing a single 60mm throttle body.

Back in the days of carbies, to make a hearty 2 litre rev to 8000-8500 a pair of 48mm side draft carbies were the go, However if you put a single 90mm carby throat onto that motor it'd be a sack-o-sheit.

Throttle bodies at different stages of the manifold/inlet tract require different sectional areas and therefore different flow rates to achieve the same actual engine inhalation CFM.

Can you grasp what i'm saying?