Greddy Vaccum Idle
 

I was jw what greddy turbo'd users vaccum is reading? Mine is kind of low, around 10-12 below 1k at idle. Just curious to see if other turbo'd 8's are holding 10 or so inches of vaccum. Thanks.

17-20" at idle

18-20

Leak :)

Yea...that's what I was thinking. That's no fun.

16-18

-60kpa

Mine sits on the low side as well, though it changes depending on the heat of the oil.
I typically see 60 kPa (17.7 in/Hg) cold and 53 kPa (15.6 in/Hg) hot.
I've found no leaks and the car doesn't behave like it has one, but that does not preclude the possibility of there being a leak somewhere.

Well, I can't figure out where a leak would be comming from either. Just curious, what kind of oil are yall using? I'm still using 5w20, but after some more milage I would like to switch to synthetic and see if it makes a difference.

Changing to synth won't make a difference, but going up on the viscosity will. Try 5w-30 or 10w-30, especially if it is hot where you are.

i don't think you're supposed to use synthetic oil with our renesis motors. stick with regular oil.

Yea well it's definitely getting hotter here, along with alot of humidity since it's springtime. Yea, I agree that upping the viscosity could help since 5w20 is like water. But, I have heard of people running synthetic w/ the turbo kit before on our motors and all is good. Yea, the manual does not reccomend synth, but it doesn't reccomend a turbo either ;).

Try a search before you post stuff like that.

You will see low vacuum at idle if your compression is low due to seal wear etc.
I have started using Mobil 1 since I put the turbo on.It meets the specs as given in my Owners Manual.I see no problem.

Well, they are all new 3mm seals. They were machined to have sum minor clearance as well b/c they expand when heated up. So, maybe since I have diff seals than everyone else the idle will be diff due to that clearance perhaps?? The motor feels too good to have a compression issue, and w/ the turbo the motor only has about 1500 miles or so on it. Also, if the compression was worsening, I feel like my car's ability to start would worsen as well, which it hasn't since I have obtained the new starter kit.

lets say youre in 3nd gear and youre at 3000rpm going 60km/h what should the in/Hg be? or should it be at PSI?



I also noticed that my in/Hg at idle is around 15 in/Hg now.

With 2nd and 3rd gen engines it was not unusual to have improving compression as the seals bed in,in some cases up to 10k miles.

Well, they used these seals in their high hp 7s. They have a machinest do the work for them and they assemble the parts, so maybe I will show sum of those symptoms as the 3rd gen motors did as well.

Ok, here is my line of thinking. When my car was in the shop, I had the guys do MazdaManiac's fixes to the turbo. I'm thinking since it's holding steady vacuum, but low, it is most likely a leak since fix #2 requires installing a vacuum nipple in the outlet pipe and plumbing a line to the wastegate. I bet they breezed through it and b/c of doing so that could easily be the culprit of my low vacuum. What damage can it do or what does it mean...I dunno. I guess it won't hurt anything for now, but I need to get that checked out as at least a possibility.

No, that can't be it. The nipple is before the throttle body. For a leak to show up on your boost gauge, it needs to be after the TB.

oh...well, like i said its not surging drastically or anything, just hangs low. I feel that if it were actually a compression problem, it would not idle w/o turning off and would surge greatly, like at least a difference of 10 inches or so rapidly before stalling. The car doesn't drive like a boost leak is present, and I can't seem to make one out at idle either. It could be spark plug related as well, although it would be kind of a stretch to say that's whats causing this. Maybe it's not hte plugs, but the wires?? I would like to use sum densos or better ngk plugs and then see what's happening so I could at least elimnate one of the causes, b/c now I have the oem plugs w/ the starter kit and I believe the new leading plugs are 6's.

ill have to check mine