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i currently have i/h/e/c and i plan to pick up a vafc this weekend..would getting my 99gsr with those bolt ons dynotuned with a vafc help much? is it worth 100 bucks getting just bolt ons tuned? thanks
DynoTune helpful w/ just boltons & vafc?
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Yes, yes yes!!! I believe SurferX gained 15 or so WHP after he tuned his Hytech setup.
You aren't going to see huge numbers with your setup though...especially with the 2" collector on that header you have.
You aren't going to see huge numbers with your setup though...especially with the 2" collector on that header you have.
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i hear fpr doesnt help out much and is a waste of money..as far as cam gears go..doesnt it not help much without cams..and as of now i dont have the money to buy any type of cams..just sticking with bolt ons..
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Cam gears are pretty much a "need" if you want to tune it precisely.
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thanks for all the replies!
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how is a b&m fpr?
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i have the b&m fpr with guage and i could feel a difference after I adjusted it. I got it over the aem b/c it was cheaper and i was told that the aem ones sometimes broke after extended use.
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Ya but it all depends on each car...
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i dont think he'll need a FPR w/ just bolt-ons b/c the stock ECU runs rich anyways. it'll probably only need to be leaned down which the VAFC can do. IMO, I wouldn't tune it w/ just bolt-ons.kamikazeteg on Feb/25/04 said:
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you can't bump the fuel up with the VAFC alone.
an fpr raises or lowers fp across the entire rpm range from 0 to redline. it cannot selectively isolate only certain rpms to richen or lean. in tuning cases you richen with it.
this is why you need both fpr and vafc. having only 1 severly limits your performance tuning.
you use the fpr to bump up where you need to and then use the VAFC to lean down the other areas that become too rich after the fpr change.
a b&m (with gauge that can be mounted on the fuel filter) is fine.
an fpr raises or lowers fp across the entire rpm range from 0 to redline. it cannot selectively isolate only certain rpms to richen or lean. in tuning cases you richen with it.
this is why you need both fpr and vafc. having only 1 severly limits your performance tuning.
you use the fpr to bump up where you need to and then use the VAFC to lean down the other areas that become too rich after the fpr change.
a b&m (with gauge that can be mounted on the fuel filter) is fine.
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I dont have any of my books right now but i think stock pressure is supposed to be somewhere around 36-38, and mine was at 33 or 34 (cant remember) when I installed the gauge. I first bumped it up to wherever stock pressure was supposed to be and then increased by 2 every run till i felt a slight bog, then i dropped it back 2 psi. This left me at 40 psi. I did not "arbitrarily bump the pressure [to] expect more HP." Every car is different and something is the matter with my fuel flow, which I still have not found out what yet. I made runs in 2nd gear and 40psi is where I found out my car likes to be.
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when you bump the fp up it'll make some rpm too rich and some will get enough.
that's why you are bogging. you haven't leaned down in the rpms that are too rich yet.
every car is different in that which rpms become too rich or too lean varies. However, the fact that only using a fpr alone is inadequate will be true for everyone. it's a blunt tuning tool. it doesn't allow for fine tuning which is what everyone needs.
PS you should specify whether the fpr reading is taken with the vacuum line on or off.
you're just starting out. we were just only talking about wide open throttle tuning. wait until you begin to understand part throttle tuning....it's even more complicated and the fpr/vafc (or any brand fuel controller) combo becomes less and less adequate the further advanced you get. the FI guys know this already.
that's why you are bogging. you haven't leaned down in the rpms that are too rich yet.
every car is different in that which rpms become too rich or too lean varies. However, the fact that only using a fpr alone is inadequate will be true for everyone. it's a blunt tuning tool. it doesn't allow for fine tuning which is what everyone needs.
PS you should specify whether the fpr reading is taken with the vacuum line on or off.
you're just starting out. we were just only talking about wide open throttle tuning. wait until you begin to understand part throttle tuning....it's even more complicated and the fpr/vafc (or any brand fuel controller) combo becomes less and less adequate the further advanced you get. the FI guys know this already.
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havent been on in a while but...
yes it was with the vacuum line on and i dont know if that was directed toward me but embarrassingly i am not just starting out. I do understand the 3 basic concepts of a fuel delivery; one is the rated volume of the pump, the second is the inside diameter of the fuel line, and the third is the pressure (in psi). All the way to.... Warren Johnson being credited with designing a high torque fuel pump in the 80's which changed fuel systems from then on. I have read what i could get a hold of in relation to partial throttle tuning, mainly what you have written. Sorry bout that but yes i do understand and am always open to learning more.
yes it was with the vacuum line on and i dont know if that was directed toward me but embarrassingly i am not just starting out. I do understand the 3 basic concepts of a fuel delivery; one is the rated volume of the pump, the second is the inside diameter of the fuel line, and the third is the pressure (in psi). All the way to.... Warren Johnson being credited with designing a high torque fuel pump in the 80's which changed fuel systems from then on. I have read what i could get a hold of in relation to partial throttle tuning, mainly what you have written. Sorry bout that but yes i do understand and am always open to learning more.
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