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Discussion Starter · #1 ·
When I am going 70-75 mph I am about 2500 roughly. I looked on the kenne bell website and the boost starts a 2K so my question is what kind of boost will I be at going those speeds? I know the KB 2.1 has a flat torque/hp curve so I can assume that I will be at 9psi through out the whole rpm band?? the reaon I ask is because town driving I can keep the car under 2K to keep it out of boost to prolong the life of the s/c and my motor but at those speeds I would be worried that I will be running uneeded boost that will just wear out my motor. I googled and searched the forum for about 30 minutes and couldn't find anything. I may have not typed the right thing in the search so if anyone could help with any of these issues that would be fantastic.:D
 

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it goes by throttle postion more than rpm. the bypass closes around 4 or 5" vacuum. You can turn 4000 rpm and still not be in boost. at 2000 rpm cruise and steady throttle, i am around 15" vacuum,push throttle to halfway point I am at around 5 psi boost. Floor it and I am at full boost instantly
 

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Your engine creates a vacuum... you know all those hoses that have a vacuum. Anyways like mentioned it is vacuum that decides boost. like limited said you could be at 5k and tapping on pedal and wont be in boost. Or you can mash it at 2k and be at full boost.
 

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Discussion Starter · #8 ·
gotcha! also to add to my boost questions.. as long as I stay out of boost a reasonable amount of time I wont be hurt on fuel mileage right? also I have 91K fro miles should I be fine to run a 2.1 KB as long as I stay out of boost a good of amount of time I drive?
 

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Check out the FAQ'a on the KB website
Kenne Bell Web Home
There is a ton of useful info about the 2.1L SC for our 4.6 GTs..

"Safety" can be a relative term. Weather or not you use an innercooler, how much Boost are you pullied for, condition of the fuel system, etc.. But most will agree the biggest factor is the tune.

Check out the website- Lots of info to help with your project.
 

· April 2012 ROTM
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+1 you shouldnt be in boost if your accelerating normally or cruising along....when you mat the gas thats when all hell breaks loose lol
 

· April 2012 ROTM
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I think the OP is debating on whether or not to go FI and just has some general questions...so as of right now he probably doesnt have a gauge lol OP...if you have any KB questions feel free to PM me...I was on your quest for knowledge about these blowers for a while too....lol
 

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+1 to these guys.. You wont be boosting at you not at WOT.
This not true with a KB, If i stab the throttle to half, I will see ~5psi. I can control the boost I see instantly by throttle postion and speed at which the pedal gets there
 

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BTW-
I've been wondering what it does if you downshift into a higher RPM?
Does it surge or anything?
 

· I Poop Entirely Way Too Much
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BTW-
I've been wondering what it does if you downshift into a higher RPM?
Does it surge or anything?
IT wont surge, If you loading the engine as your goin into the lower gear youll have boost that will go right into the engine. if not the bypass/bov will be open releasing the air. Unless your power shifting the bypass/bov will be open during the shift/while off throttle and wont close til you hit the gas and load the engine.
 

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Thats not how mine was... Maybe your pedal is adjusted different than mine, but mine didnt have any boost until the pedal was at the floor.
pedal adj. has nothing to do with it lol,you had problems, all KB's and pd type blowers behave the way I described
 

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Ya i start getting boost at like 1/4, don't get full boost till about 3/4-WOT at the throttle position. At about half im at 10psi. Wot 15.5 or so.
 
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