I recently installed a new malloy reman engine and so far i've put about 600 miles on it. The problem is that I'm only getting about 15-16 inHG of vac at 800rpms. I have eliminated all my emissions since where i live doesn't require testing. I've also done the seq simplification. I'm hoping that the engine isn't bad and it's only a vac leak but i doubled check everything esp the vac lines when reinstalling the thing. any suggestions? thank you.. oh one more thing I am also running pretty rich, everytime i turn off the car and the motor gets cold, when i restart it grey fuel smelling smoke comes out but clears up after a few min or so once the car reaches temp. I'm still running the stock ECU.

 

thats ok vacuume as far as i know.. anything between 12-18 should be ok... also, its a new motor so it doesnt have full compression yet.. but if your worried, get a compression check done... my car pulls 13inHG vac at idle...

 

I agree. That is normal for the car.

 

yeah i get about 18-19 of vac at idle

 

Yeah 15-16 sounds fine.

^ I usually get about 18-19 as well.

 

vacuum w increase w miles. you are probably o k.

howard coleman

 

cool thank you i'll keep watching as i put more miles on the car

 

If you removed emissions, that means you also got rid of the air pump. The stock ECU will idle rough, have low vacuum, and have bad throttle transition without the air pump. If you get a PowerFC or something, that problem will go away.

If you got rid of the emissions, that means you have no cats on the car, and no cats + stock ECU = buy another motor. Get an aftermarket ECU pronto.

Dale

 

16 is normal, that's what i had when my reman went in, i ask my mechanic, and he said that's how all them read.

 

I am dissapointed to see someone who is apparently knowledgeable spill that babble. Don't you realize that myth has been disproven MANY times on end now?

Just give the engine time Brian , it will come up with more miles as spoken before. As well if you have the stock ECU and the airpump is off it will cause a rough idle...also as said before. But the new engine comment is totally incorrect as long as you stay at or under 10 PSI. As proven many many many times. By myself included. Rynberg and many others

 

well right now the WG pill has been take out so running no pill in that line hopefully will limit the boost. Plus I have been keeping in check and no WOT or anything of the sort. haha it's kind of hard trying to stay underboost when going onto the freeway (hawaii's freeways are really badly designed) so yah trying my best to break this dam engine in right. thank you for all the relpies tho

 

Hey hobbez, do you live on oahu, if so did you install the motor yourself or take it to a shop?

 

i have 20-21 vacuum at 650 rpms

 

I seriously doubt that. Are you being serious? if so that is some kind of record.

 

I'm not sure that vacuum number... or even actual compression numbers are the end all be all of engine health or even power potential on a turbocharged rotary.... so long as it's within a certain spec. Also, vacuum at idle can be affected by alot of variable, including tuning, load, how the bleed screw is set, etc.

My mild streetport, with open exhaust, and almost zero accessories (no PS, AC, or AP) pulls about 14 lbs. With a hiflo cat, airpump, PS, AC, it pulled about 16 lbs.

 

The problem with an open exhaust (Is that what you have?) is that you most likely will have boost CREEP (the WG is not large enough to limit the boost), so even without pills you can over-boost and incur all of the related problems (detonation due to running lean, etc.).

 

going by the vaccum reading off the boost gauge is not very accurate. It will be different from place to place. The higher you are the more it will read.

 

thank you for all the replies. Yes I watch very carefully for boost creep. I have yet to go WOT on the engine probably by the time it's fully broken in i'll have a PFC. I have yet to take it over 4k too since i only have 700ish miles on the car. Well as for like altitude live in hawaii, so I would assume i'm not living in a very high altitude area.

 

IMO, anything greater than 14inHg on a stock port motor is fine vacuum. I've never seen a rotary with a properly set idle (below 900rpm) pull more than 17", even in cases where compression measured well over 120psi.

A streetported engine can pull anywhere from 15-10inHg of vacuum depending on the port style and idle rpm.

Vacuum reading comparisons are generally only useful on the same engine, not from engine to engine or gauge to gauge. IF, for instance, you've had the same engine and gauge for 2 years and are accustomed to seeing 15", yet one day you see only 12", you might have a good cause for concern. Yet, if you compare one car/engine/gauge to another, you'll likely get different readings, due to differences in engine compression, porting, gauge accuracy, and elevation.

 

Ya i do have 20-21 at 650 rpms. My buddy with a single turbo(nieto) helped me put in my new defi boost gauge and the car hits 12 10 12 boost with my mods.I was kinda freaked out by it myself! the vacuum does go down to 18-19 when i turn the ac on.BTW i am the guy that bought the 93 base with 8300 original miles on it.

 

At 650rpms?! I find that REALLY difficult to believe (unless your boost gauge is reading vaccum incorrectly). At what elevation were you measuring this much vaccum at such a low RPM?

 

i am located in charleston sc we are sea level,we are called the low country for that reason.l I doubt that my new defi gauge is inaccurate,but any thing is possible i guess.here are some more stats, i got over 27 mpg on a hwy trip to fla 321 miles one way running on cruise at 70. rpms were 2600-2700.The car has not burned 1 drop of oil in 2000 miles,my oil pressure is at 80 at 2700 rpm. The car now has 10, 400 miles on it. When i bought it the battery was dead,we replaced it and the car ran perfect after sitting in a barn for its whole life only being driven like 700 miles a year.Every one in chas that has seen my car is blown away,it even still smells new.I got real lucky.Any more doubters are free to pm any rx7 club members here in chas.I am having the next meeting at my house. All rx7 club members on this forum are welcome to attend our cookout/meeting on june 11,and you can check my car out for yourself.

 

i had 20-21 when i first got the car when it had 15k miles on it and was stock. i think the car idles slightly higher when it has less than 20k miles. i think i read that somewhere, hence more vac.

 

Thanks man,i am glad someone believes me w/o seeing it.The only thing that puzzles me is that when i did my mods and swapped out the stock ecu for a m2 stage 3 the idle went from 900 to 650.So my idle is actually too low,but when i turn on the ac the idle goes up to 900 and the vac at idle drops to 18-19.So is the lower idle giving me a higher vac? Like i said i get 12-10-12 boost,but when i am just driving normal it is always in runs in neg boost.

 

Not saying you are wrong, but a lot of people say Defi makes quality gauges - not saying they do not, but I bought a brand new boost gauge from them and it reads about 1 psi low.

I may come to that meeting, I live in Charlotte.