Bathurst

Just did a rebuild and installed a single turbo... The engine seems ok and everything but the vaccum at idle seems a little low..it shows around -298 to -350 mmhg on thePowerfc i think...if i let it idle for a while it keeps building vaccum and goes to around -400 to -450...

I have all the twin turbo vaccums blocked now... i mean the ones that need to be blocked... is it a vaccum leak??

thanks

BigIslandSevens

iTrader: (4)

are you ported at all. I f I am correct, 350mmhg is equal to around 13.***inHg.

For a street ported engine vaccum is usually a bit lower. And if you just rebuilt it and it is not broken in/ seals seated, then the compression/vaccum can be a little low. Usually it increases with the engine as it seats in.

Does the engine shake at all( more than normal, I mean semi- violently) Usually if there is a big enough vaccum leak the engine will shake quite a bit.


If you could take pics of your vaccum set-up that would probably help out deciding if you have all the correct nipples capped.Also maybe posting this in the single section may be more helpfull. As the vaccum diagrams are way different, and most here still have twins.

As well do you have all the block off plates needed? Or are they not needed do to your location, and the engine not requiring them.( ACV, EGR,Etc..)

Bathurst

I do not have the block off plates.. and my engine has done around 1000 kms now i.e 625 miles i am giving it slight boosts now... can it be that the vaccum will build up eventually..this friend on mine who did a rebuild on his car the same week as i did has better vaccum but he used old seals and rotor housings.. i used new seals and almost new rotor housings...

Tim Benton

iTrader: (1)

like the big kahuna asked, was the engine ported any?

Tim

oakridgerx7

every single engine ive had in my 7(3 engines) only had about 12-14inHg of vacuum. some people say that is normal, others say 18-30 inHg is normal.

BTW that is a mazda reman with stock ports

Sonny

My Mazda reman with stock ports pulls about 18" of vacuum at idle. Accuracy of your gauge and your elevation will effect this number a lot. My in-laws live at 4500 ft. I always see less vacuum there as well as a big hit in power. That's why I gotta live it sea level.

Sonny