ALFAGTV6.COM

Greg Gordon · Post by **Greg Gordon** » Tue Mar 22, 2005 3:15 pm

That's really great.

Mats · Post by **Mats** » Wed Mar 23, 2005 1:06 am

93dbA at the track with no muffler?? That sounds like an impossible dream to me.

What is your intake like, some kind on muffling going on there?
How is the test done, at idle or something?

Reale · Post by **Reale** » Wed Mar 23, 2005 5:39 am

Well, it helps that most of time they are taking sound from the driver's LEFT-so the tailpipe exits away. But, I have been to tracks where sound is on the right, and we are still under 100 dB-usually 95-98dB. Most people comment that the car sounds GREAT, as we all already know. I have talked to other guys who run similar open exhaust arrangements, and they have had no sound problems.
SCCA sound limit is 103dB.
Now, the CSC primaries merge together into 2 1/2" OD pipes under the car. I run these together into a home-made 2 into 1 merge just under where the driveshaft center support bearing would be. A 3" pipe exits the merge and runs that way out the side. So, some expansion is going on.
Richard Jemison ran straight pipes out the side individually on his 3L GT2 car, and he never had sound problems, either.

Has anybody experimented with different length primary/secondary pipes, merge/no merge, or an H-pipe to equalize the banks?
I know all about the math involved, but I am interested in actual hard data. I am looking to take a couple of different configurations to the dyno next time.

-Al

Post by **Zamani** » Wed Mar 23, 2005 6:28 am

3" intake pipe sounds good. Some of the peeps here laughed at me when I had a 4" intake pipe running into the throttle body. Now I've modified the stock airbox to accomodate a 4" pipe. I am also not using an AFM.

As for headers, I only have the SZ. I asked Beninca about headers and he said short and big primaries are the way to go for a fast road car. He said longer primaries are good for high rpm racers. I trust him because he himself is a machinst and have extensive dyno time (he has 1-2 dynoes at his shop).

I'm using a merge collector from burnsstainless.com. But I have no hard data (no dyno time).

Greg Gordon · Post by **Greg Gordon** » Wed Mar 23, 2005 7:17 am

My money is on the "X" pipe at dyno time for most power under the curve. Probably a good "Y" pipe for top end power. I have no hard data though, just guessing based on experience.

Murray · Post by **Murray** » Mon Apr 11, 2005 1:09 pm

Well I thought I'd just post a conclusion to this experience of rebuilding my 85 GTV6 2.5L engine.This weekend I put it to the test.I spent two days on the track and ran up 250 miles.At one point I was concentrating on a pass and noticed my Tach was buried .Won't let that happen again ! No problems no oil consumption and she's definitely putting out a bit more power.Total miles on rebuild is now about 2000 . I'm guessing that if she didn't spit out any metal parts under these conditions all should be well for a long time.Greg's suggestion of rotating pistons 90 deg.and using Total Seal rings seems to be working out perfectly.
Thank you all for your input and suggestions it made the task a lot easier than I had anticipated.I'll run it on a Dyno this summer to see how the numbers compare to pre-rebuild ones.

93dB