pzull

Rob,
How would one reduce the oscillations on the flap? I'll be putting my car on a fuelk mix sensor to see what the A/F mix is across the rpm range. Doing my research on the tuner before taking any plunges, otherwise it's a piggy back first so at least I've got full range maps.

Cupcar#12

Dennis,
a custom chip would do it - but not completly you are still going to have the inherent inaccuracies of the stock A/F sensor. To do a custom chip you would need to re-mapp the GIAC chip to provide a more stable mix in the higher RPM band - but this is rally determinded by the Torque curve. in Joey's car it is pretty consistant but rises when the mix is leaned at 47-4800 rpm to peak and then bottoms as the RPM's rise.
you might get more power out of a leaning the mix sooner as it comes on cam, there is no point adjusting it before it comes on cam as the engine is not working in it's most effecient range.
I believe the 933 A/F sensor works a bit better but the real culprits could be a number of factors, Gas, temp, valve adjustment, etc.

Christer

except you won't get 30hp and 30 lb/ft gains from those alone......

johnfm

He 'may' not get 30 hp & 30 lb/ft gains. But, in my experience, his butt will tell him he has a bit more pull and slightly more 'throttle response', and the sound is fantastic.

Maybe Erick can do a before & after dyno pull and settle whether a small spend on cat bypass & G-pipe is worthwhile VS ££££££££££££ on a GHL -style header system.

Christer

I hope so. Surely I cannot be the only one that actually wants to know what if anything our money actually gets us at the end of the day?

joey bagadonuts

No. I think everyone who reads these threads wants to know "Does this thing actually do anything? Or am I wasting my money?"

I completely understand and appreciate your skepticism, Christer. There are a lot of "snake oil" salesmen out there promising much and delivering very little. Even as I watched my car on the dyno roaring its way up to 6,000 rpm, I thought to myself "Just please let it be over 200." When the tech told me "228" I was simply relieved that I hadn't pissed away a thousand dollars (chip $400, intake $200, g-pipe $150, cat bypass $200). The elation came afterwards.

Thanks for maintaining the balance, C-. Now stop mucking around and go out and get that cone filter!

joey bagadonuts

Erick,

If I was putting together a Christmas list, I'd say your biggest bang for buck would come from the g-pipe and cone filter (as shown on the previous page). Yeah, it seems gimmicky but when you remove the airbox you'll see that the Factory design is VERY restrictive. It's a tiny hole compared to the size of that filter!

Then I'd add the cat bypass--that's a serious commitment to performance. It's not only loud but also a little fumey and hell on gas mileage. It does add some pull but it's not quite as painless as the other two.

Finally, the chip. It's expensive and didn't make a difference in the 0-60 numbers, so that's very questionable. If you ever Club Race your car, you can't use it in stock class so you might be better off sticking with what you have.

Cupcar#12

I think one could draw a specific formula from this thread - we would need another person to do the mod's of course and get it dyno'd. But from a bolt on perspective it seems that Joey's mod's point to a real increase that other can use.
So...
GIAC chip
Cone Filter (K&N or other)
Secondary bypass
Cat Bypass

these together should net you 225 Rear wheel HP which is pretty good given the cost. +/- 2000.00
not to mention you will loose about 50 Lbs in the rear of the car. which is good for another few HP on the road but not on the dyno of course.

My 1.5 Cents

joey bagadonuts

In case folks were wondering, here's what the back side of the airbox looks like. The small rectangular bracket (circled) is where the air exits. With a cone filter, the bracket supplied is rounded and much less restrictive.

dove

I'm due to fit a cat bypass/g-pipe and performance chip to my car and have looked into this a great deal and dont expect to get anymore gain than 20-25 hp fitting these items.The benefit only seems to be in eliminating mid range flat spots which is good,but significant hp gains that vastly improve performance I dont expect.Induction kits & K&N filters seem pointless unless you want a nice noise,there seems to be some gains with a drilled airbox which is good because it costs nothing to do.If you want to go fast the best way is to shed some of the cars weight.I'll be quite happy with my 270-275 bhp 964.
Paul
C2 cab

johnfm

Dove

are you using Wayne Schofield....

....or some guy you know in Suffolk who'll do it for £20 (couldn't resist.....)

Doug H

I am going on the dyno to try out different chips and the what to by pass issues. I'll post my numbers. I am hoping for 290 and fee pretty confident I should see 290. With new clutch and cat by-pass, I am running 5.1s easy and I have a heavy car with big 18 inch Speedlines.

Cupcar#12

can you post the entire graph w/ A/F
thx

Christer

I doubt if these mods save 50lbs. I saved 22kgs/49lbs by replacing the whole original exhaust with a system that uses only one muffler. I had the old system weighed compared to the new one. You will definitely lose some weight though. That is indisputable.

Joey, yes I am only trying to keep a balanced view - I am not trying to be negative about the whole thing.

joey bagadonuts

Not quite, Paul. This is a mod which I evaluated in back-to-back tests with the G-Tech. By switching to the cone filter, I dropped my 0-60 time by 0.3 seconds over the drilled airbox w/ K&N panel filter. The silly thing actually made a significant difference.