Another Fast Intentions HFC / Exhaust Review! (WARNING: LOTS OF PICS)

phelan

Dyno results! I did runs on a DynoPack system at Church Automotive (out in the middle of nowhere, but Shawn knows what he's doing, and is very friendly about things. I like going there for all of my tuning and dyno stuff.) And here are the results!





So we're basically looking at a little under +19hp/10lbft of torque with this system. Note that DynaPacks tend to read higher than DynoJets or similar systems. Car is apparently leaned out...I initially assumed an incorrect "proper" AFR for an NA car. Sorry! Still, a tune could probably help out a little here.

The exhaust system has definitely quieted down - but then again, it's still a ridiculous howl when you have high engine load at low rpms... It's still a beast on the road, no doubt about it. However, it's not the raucous roar it was when I first got it. Just a word of warning to those who like theirs LOUD...go with SACLAM or something.

Also, be prepared for some popping to occur from the released backpressure. Makes the car sound 'racey', and some people may NOT like it...I was certainly surprised, so just warnin' you all. See Tony's response on page 2 for better explanations.

Another note: I may or may not do a video with this current configuration. Fusz put an EXCELLENT video up in the main thread.

Yes it has stillen parts in with it but...eh...close enough? I plan to take videos when I get the Injen intakes.


Still loving this system!

F.I. Inc.

Phelan,

Your Air Fuel Ratio is NOT too rich. It is on the leaner side. The higher the number the leaner the A/F. The lower the number, the richer the A/F.

Optimum A/F for a naturally aspirated car is: 12.6:1-13.0:1

You are right in the optimum area.

Now, this makes sense that you car has leaned out. When you relieve back pressure like you have you lean a car out. Now, your mass air meter is designed to compensate for modifications. It does but only to an extent. I am looking at your dyno charts and I can tell you that the car leaned out. They are higher than the previous numbers. Also one thing to keep in mind, A/F numbers will be a different number the further back the reading is taken. The optimum point to take an A/f ratio reading on a dyno is before the catalytic converters. So to recap, I know that a set of aftermarket cats and cat back exhaust system such as ours WILL NOT lean a car out to the point of DANGER. However, it doesn't hurt to get a car tuned after the fact.

The popping noise you hear sometimes on deceleration is the freed up back pressure due to the free flowing exhaust.

One more thing to add, even though you are on a dynapak you are still hooked up to the axles, that is still considered a rear wheel or (at the tires reading)! To record flywheel power you have to dyno an engine on an engine dyno out of the car.

Call me if you need anything...

Thanks, Tony

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drisko

This is one of the things I really like about the exhaust system. The "popping" sounds awesome to me.

Push370zzz

I believe that second graph violates the vertical line test.

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cjr1881

hey uh... a couple of comments. Your rear bumper should be all red, it looks really cheap the way it is. And the second thing is, you said it twice at least that you had carbon fiber resonators. Those are mufflers buddy.

adampetrasek

Your first post on the forums is this?!?

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