New Dansk euro pre-muffler and sport exhaust. Do I need new chip because of mods.?

joeb · 07-31-2004, 03:41 PM

I just installed a new muffler and pre-muffler on my 1985 3.2. Great sound but my seat of the pants dyno can detect little or no difference in power. I currently have a Euro chip. ( That's what the receipt from the PO called it.) Should I get a new chip programmed for my new exhaust system? The car ran strong before the changes and maybe I'm expecting too much but will a new chip help? Should I replace my O2 sensor. Thanks for any advice.

aways · 07-31-2004, 08:09 PM

I'm no expert here, but I've been told that the chip should be
programmed for a premuffler+sport muffler. Apparently they
program to be a little richer at high RPM. Contact Steve Wong,
and he'll be able to help you.

chuckr · 08-01-2004, 05:21 AM

Do a search here on chips.... or go to www.911chips.com

Wavey · 08-01-2004, 05:44 AM

A Steve Wong chip (911chips.com) will really wake the car up and put that exhaust system to work. It's the best money you could spend at this point. No more Carrera lag, immediate throttle response across the power band, more power everywhere. Do it, you won't be sorry.

JeremyD · JeremyD's Garage

joeb - not required, but you will be glad you did.

NY65912 · 08-01-2004, 07:09 AM

You NEED the Steve W chip! (Sold here by our hosts)

Mike

Wil Ferch · 08-02-2004, 06:26 AM

I hope Steve W chimes-in here, because my dense head can't understand something ...

Steve offers a wonderful product in his chip, and I am entirely satisfied with my set up that includes his chip as well as a Euro pre-muffler, a dual-out muffler mod and a cup/KN air filter arrangement ( the last item of no particular HP value)....more of an access issue.

But... I was under the impression that progressive opening-up of the exhaust and/or intake requires progressively more fuel....to avoid going lean. Steve said as much in my eariler conversations with him. Later posts by Steve indicate , however, that the stock chip is "too rich" at WOT...and that his custom tuning actually leans-out that portion of the stock over-enrichment a bit....to net more hp.

So Steve.... if you're out there....can you clarify ?? Would the stock programming at WOT be safe ( i.e...not "too lean")...but is simply not optimized for HP ( being a bit too rich?).

--Wil

Steve W · Steve W's Garage

Wil, it actually is a bit more complicated than that. Basically 88-89 Carreras are programmed very at WOT in the upper rpm zones. Cutting back on fuel here raises the hp. I think on one of our dyno runs, we actually gained something like 20-25 hp at 6300 rpm over the stock chip. I will post it soon when I get a chance. On the 24 pin 84-84 Carreras, they are not as rich, but actually need extra fuel at WOT below 5000 rpm. A premuffler/bypass pipe seems to create some type of exhaust resonance around 5000 rpm which requires extra fuel here to keep from going lean. In part throttle situations, all chips benefit from extra fuel in the part throttle regions, to lean low rpm bog and exhaust popping from the more open exhaust, and improving response and torque here, plus the extra fuel allows additional tweaking of the ignition maps. On all chips, above 6200 rpm, the fuel goes super rich, killing hp so you actually feel like hitting a wall in power.

The OEMs do this intentionally because the rich mixtures at WOT cools the cat preventing the meltdown of the cells. While not as important in the U.S., it probably is more of an concern driving on the autobahn at sustained WOT in the max rpm zone.

Wil Ferch · 08-02-2004, 08:27 AM

Thanks for the clarification, Steve....
-Wil

08-02-2004, 09:19 AM

joeb,

I have an 89 euro w/ a similar set-up. I think the car would run better overall with a chip programmed for what I have.

I recommend to read the reviews on Steve Wong's website, they will help with your decision. I did, my chip will hopefully be here tomorrow.

dickster · 05:17 AM

joeb,

LOL, FORGET "seat of the pants dyno"!!! the only way you're gonna know is to get it done properly.

i have the same system as you and measured about 12-14hp more on the dyno

- but it doesn't feel any quicker.

i'll have to get a steve w chip one day and dyno that.

the biggest difference will be putting the premuffler in place of the oe cat. from what i've read low comp. engines without the cat (swiss models apparently, although mine had one) made the same power as higher comp engines.

jabb · 08-03-2004, 05:12 AM

Whats the difference between a pre Muffler and Just Gutting out your old Cat. Is there any additional benefit to the pre muffler ?

Purrybonker · 08-03-2004, 07:36 AM

Quote:

Originally posted by joeb
I just installed a new muffler and pre-muffler on my 1985 3.2. Great sound but my seat of the pants dyno can detect little or no difference in power. I currently have a Euro chip. ( That's what the receipt from the PO called it.) Should I get a new chip programmed for my new exhaust system? The car ran strong before the changes and maybe I'm expecting too much but will a new chip help? Should I replace my O2 sensor. Thanks for any advice.

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