What is a good Vaccume for a Stealth Ram?
04-01-2014, 08:33 PM
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Car: 88 Iroc Z
Engine: L98 350
Transmission: 700 R4
What is a good Vaccume for a Stealth Ram?
I'm tuning my HSR I was wondering what is a good baseline is for Vacuum at idle?
I'm trying to get my set up to idle well and I want to ensure I have enough Vacuum at idle with the Cam I have.
I'm trying to drop my idle speed as low as I can and keep a reasonable Vac for power breaks and the map sensor to work correctly.
I'm trying to get my set up to idle well and I want to ensure I have enough Vacuum at idle with the Cam I have.
I'm trying to drop my idle speed as low as I can and keep a reasonable Vac for power breaks and the map sensor to work correctly.
04-01-2014, 08:34 PM
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: What is a good Vaccume for a Stealth Ram?
It depends on the cam.
04-01-2014, 09:21 PM
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Car: 88 Iroc Z
Engine: L98 350
Transmission: 700 R4
Re: What is a good Vaccume for a Stealth Ram?
But what is a good Vacuum you can increase Vacuum in bigger cam engines by increasing idle speed?
04-02-2014, 07:16 AM
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Car: 89' IROCZ
Engine: 5.7 L98
Transmission: 700r4
Re: What is a good Vaccume for a Stealth Ram?
I get 22" at idle with a HSR and a stock cam. All vac operated devices work correctly.
04-02-2014, 09:13 AM
#5
Re: What is a good Vaccume for a Stealth Ram?
It really depends on the cam. What cam is it? I just swapped cams in my 94gt and went from stock to an aftermarket. Dropped from 19-20 to 14-15 inches at idle. If you are seeing real low you habe a vacume leak. Set idle, set timing, vacume will fall where it will you cant change it.
04-02-2014, 09:18 AM
#6
Re: What is a good Vaccume for a Stealth Ram?
Your tb plate is going to give you fits btw. The iac needs to be between 5-10% correction when Idle is established. You will not get correct readings if there is a hole in the plate. Extra air is needed , the iac will supply it. Put on your stock tb and adjust the settings. Everytime you open the tb blades you have to do a tps reset on the holley hp. Youll get there, its confusing at first but when all said and done youll wonder why you didnt get it before.
04-14-2014, 05:33 AM
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Car: 89 IROC
Engine: 6.8 HSR N2O
Transmission: TKO 600
Axle/Gears: 9" Moser 3.50 True trac
Re: What is a good Vaccume for a Stealth Ram?
Yes, it depends on the cam overlap and engine size, transmission type and idle speed. Raising the idle RPM does help but I didn't notice a difference on the vacuum gauge. Changing the base timing at idle seemed to have a slight affect on vac.
With a 350 and a 212/218 cam on 112LSA (about 42OL) my engine would idle very well at 700RPM and pull about 16" of vacuum.
With my new build, 421cid and a 236/242 cam on 112LSA (about 69OL) I am hoping for about 10-14" vacuum.
From what I can tell you can get away with about 10" vacuum with a manual trans and still have power brakes work well. An automatic may need more vac in neutral to make the accessories (brakes) work well when in gear. It really depends on the whole combination. Since I upgraded to LS1 brakes, the pedal effort was reduced so much that I think I can get away with less vacuum.
With a 350 and a 212/218 cam on 112LSA (about 42OL) my engine would idle very well at 700RPM and pull about 16" of vacuum.
With my new build, 421cid and a 236/242 cam on 112LSA (about 69OL) I am hoping for about 10-14" vacuum.
From what I can tell you can get away with about 10" vacuum with a manual trans and still have power brakes work well. An automatic may need more vac in neutral to make the accessories (brakes) work well when in gear. It really depends on the whole combination. Since I upgraded to LS1 brakes, the pedal effort was reduced so much that I think I can get away with less vacuum.
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