how long after exhaust and hfc installation does it take to feel the power???
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#4
i installed FI metallic cats + FI exhaust and felt no low end loss - in fact my g-tech rr measured an immediate gain in the 0-60. haven't had time to go do a 1/4 mile run on an open stretch yet... waiting for the 500 mile mark on the exhaust.
i would think the HKS would have better low end gain because of smaller piping - but I've never actually seen a dyno of the HKS.
i would think the HKS would have better low end gain because of smaller piping - but I've never actually seen a dyno of the HKS.
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Originally Posted by rcdash
i installed FI metallic cats + FI exhaust and felt no low end loss - in fact my g-tech rr measured an immediate gain in the 0-60. haven't had time to go do a 1/4 mile run on an open stretch yet... waiting for the 500 mile mark on the exhaust.
i would think the HKS would have better low end gain because of smaller piping - but I've never actually seen a dyno of the HKS.
i would think the HKS would have better low end gain because of smaller piping - but I've never actually seen a dyno of the HKS.
#13
Originally Posted by jiggafree
i didnt know there was a built in waiting period before the hp/torque kicks in
?? im confused
![Confused](https://g35driver.com/forums/images/smilies/confused.gif)
The lower rpm loss is associated with the reduced exhaust velocity from the larger pipes and HFCs. The larger piping greatly reduced the gas velocity in the lower rpms which doesn't allow the gases to get pulled from the heads effectively. The end result is a slower in the lower and midrange rpms.
IMO, if you don't feel much increase right away and you actually feel the loss, you can be pretty certain it's not going get better with time. I think a lot of people that end up feeling increases days later are actually get used to the reduced power and they are confusing the additional noise with an increase in power (ie the power of suggestion).
#14
Originally Posted by DaveB
To make the most of it, some tuning is in order.
The lower rpm loss is associated with the reduced exhaust velocity from the larger pipes and HFCs. The larger piping greatly reduced the gas velocity in the lower rpms which doesn't allow the gases to get pulled from the heads effectively. The end result is a slower in the lower and midrange rpms.
IMO, if you don't feel much increase right away and you actually feel the loss, you can be pretty certain it's not going get better with time. I think a lot of people that end up feeling increases days later are actually get used to the reduced power and they are confusing the additional noise with an increase in power (ie the power of suggestion).
The lower rpm loss is associated with the reduced exhaust velocity from the larger pipes and HFCs. The larger piping greatly reduced the gas velocity in the lower rpms which doesn't allow the gases to get pulled from the heads effectively. The end result is a slower in the lower and midrange rpms.
IMO, if you don't feel much increase right away and you actually feel the loss, you can be pretty certain it's not going get better with time. I think a lot of people that end up feeling increases days later are actually get used to the reduced power and they are confusing the additional noise with an increase in power (ie the power of suggestion).
#15
If you look at the Fast Intentions web site and the dyno plots there, you'll see that the combination on our test car, as well as others, have shown that there is only a drop from about 2150 - 2300 - only 150RPM worth of drop - and gain EVERYWHERE else.
The HKS system was not designed to work with HFC or testpipes, so your augmenting it's design. The FI system, its testpipes and CATS are all designed to specifically compliment each other...and that's why the combination works best as well.
I'm not really trying to sell you guys - just educated why they work better in some cases than others. The big pipe-less back-pressure power loss theory only works in mismatched and poorly designed systems - not specifically match tuned systems - like the FI.
Rick
The HKS system was not designed to work with HFC or testpipes, so your augmenting it's design. The FI system, its testpipes and CATS are all designed to specifically compliment each other...and that's why the combination works best as well.
I'm not really trying to sell you guys - just educated why they work better in some cases than others. The big pipe-less back-pressure power loss theory only works in mismatched and poorly designed systems - not specifically match tuned systems - like the FI.
Rick