4AGZE Guru or at least Repair Manual Owner wanted.

[ra23celica]

Can someone please tell me what the inlet manifold vacuum spec's are for a 4AGZE engine please?
Measured after the throttle body how many inches of mercury should it be? Or hectopascals or millibarbars or whatever units the TSRM / BGB says...thanks.

[Ben Wilson]

Measured at the inlet manifold, I'm getting around 20 inHg at idle.

Mine's not standard, but the vacuum should be around the same.

[Hen]

I concur with Ben above. I'm running stock smallport head, cams and intake mani.

Hen

[myne]

ditto, 20 on idle.

[ra23celica]

Thanks guys, very good to know. The reason i ask is that I have an old ToyMods Tech article that talks about 8 to 10 inches and that did not seem right at all, so I needed real life feedback.
Cheers,
Mitch

[myne]

8 and uh... above is when the supercharger kicks in.

[ra23celica]

OK.
So I should re-set my logic....its about 20mmHg at idle and 8 to 10mmHg once S/C clutch engages - yes?

[myne]

Yup. Once the gauge climbs above 8, the SC relay switches the SC on.

[myne]

~
10psi ^v boost v^
9
~
2
1psi ^ boost ^
0"hg (Naturally aspirated WOT)
1"hg
~
7"hg
8"hg ^ power (SC kicks in) ^
9"hg v cruise v
10"hg
~
18"hg
19"hg ^ cruise ^
20"hg Idle
21"hg v compression braking v
~
26"hg ^ compression braking ^