i just wanted to compare notes, i just finished putting my car together with a garret TS04 turbo and rebuilt street ported motor. i used 89 turbo II low compression rotors with 3mm seals. with this setup im getting about 14 to 15 psi vacume with a slight miss when in idle. sometimes it gets real bad and drops to like 10 or 11 psi and a real nasty miss. i thought maybe this motoe was blown but you check the vacume sepererately front and back and they are the same.

thanks in advance
ROB

 

on my stock port engine I get ~17 at 850rpm. I would think your idle vacuum is fine. btw it's inhg not psi

 

I get around 11in/hg at 1000rpm idle, with a small miss. With no load the idle drops down to about 750 and i pull about 9in/hg with moderate missing.

The Motor is a Pineapple Racing Stage 3 with Large Race Port, stock turbo's. Sounds like your Vacuum numbers are good to me.

 

r u guys using stock or aftermarket ECU's. Right now im using the stock ECU, but i do have a Haltec E6K that i plan on installing soon. its just that that vacume and miss has had me worried. the mech that built the engine said i might have slightly curved the apex seals causing the vacume to drop, but that didnt really make much sense to me. Motor pulls real hard in boost so i really cant explain it

 

You are running a ported motor and single turbo on the stock ECU?

Vacuum on a ported motor is usually between 11-14

Jason

 

I have a mild/moderate port with a T04S and I run anywhere from 14-16 inches Hg depending on the AFR. Try running your AFR at around 12.8 at idle and see if your vacuum picks up some.

Brian

 

i usually see around 15-16inHg on my ported motor

 

just got mine back from pineapple 1800 miles ago. "road race" street port (not race port), 11-12 inhg at idle ~850rpm or so. looks ok to me too.

 

Half bridge , 1500 rpm idle and 9-10 " Hg vacuum.

 

-60 psi at 1000 RPMs on Profec B Spec II which equals about 12.5 inches of Hg on a "very large" streetport.

 

well... based on all your posts so far. it looks like my engine is fine. im at 13hg at 1100 rpm just checked last night.

thanks for all the responses

rob

 

The miss is from the stock ECU being to rich and timing too retarded at idle for that vacume range. Your idle vacume is ok if everything else checks out find.