Lorax

What are you getting... state your vehicle type, modifications (especially exhaust), mileage etc.

Dougs951

1987 951 Instant RWHP kit, recent engine rebuild with around 10k miles. Stock Exhaust with a cat delete.
18-20 inhg of vac

Lorax

I forgot to mention post your altitude as well.

TurboTommy

Is the assumption stock camshaft; 'cause anything other than stock cam is another situation

Keithr726

86 951, 125k miles, 20mmHg when warm. venturi delete, resealed TB, epoxy sealed ICV, scivision maf +max chips, accuboost mbc, synapse wg, evo bypass, 55# injectors, LR IC, 89 headers+crossover, 2.5" testpipe + B&B catback

supes6

86 951 stock, venturi delete, 18" hg. was reading 20" before I set the idle adjustment screw properly.

jerome951

17mm HG at 1100 rpm idle
Stock 122k mile motor but fresh head, ICV delete, 3" LR exhaust (cat delete).

I install my cat for street driving and notice no difference in vacuum at idle

76 911s

20mmHG idle at sea level. Vitesse stg 2 on a 140,000km motor, Lindsey 3", no cat, adj FPR, 72lb injectors, TiAL 38, MBC, Forge DV, SFR IC Pipes, silicone vaccuum lines, Laust VM for engine mods.

fbgh2o

18-19 inHG at sea level at 950 rpm idle. 85K miles. New vacuum hoses, venturi delete, new Vitesse MAF, Lindsey 3" cat delete, cycling valve still in place.

gregeast

12 inHG. 5000 ft. '87 951. Venturi delete, resealed TB, cat-delete, stock exhaust, Vitesse MAF, rebuilt head.

theedge

At sea level ive always been around 20inHg when warm. Even on my 216k mile engine, and on the engine in my sig as well.

Chris White

23-24" on an MID sleeved engine 800' above sea level.

Mike Lindsey

I see you don't have a catagory for 4-5".

Lorax

lol...

That would be a "Write-in"

Lorax

Mike maybe you can help me. I am trying to find out why I am getting only 16in of vac when most are getting 21. I have gone through every single hose and seal. I have pressure tested my intake and been able to find no leaks. My ICV is epoxied, as well as my AOS.

I am freaking obsessed with boost and exhaust leaks. Really obsessed. I must solve this.

What else could cause low vac with our cars?

I have tested the vac with several gauges at different points in the system as well. I have also blocked off the ICV and tested it so I know that isn't the problem.