My Custom 2.5 Inch Down Pipe 3100

[AWeb80]

Since nobody makes an aftermarket one.....which is fine w/ me....I'd rather to my own stuff......





Got the pipe from here
http://www.speedwaymotors.com/p/5423...side%20exhaust


I live 10 mins from the warehouse ...... :high5:








Stock 3100 DP.......BARELY 1.5" inside Diam.........that is horrible....















Stock Flange ready to weld.........





Not much room there.....~1" either side...so my measurements had to be RIGHT








Now the ugliest welds in the world...........But I don't care, nobody will see them, they work, and I have the satisfaction of doing it myself....














Didn't take any measurements.....ran out of time...was too busy fitting and such to worry about that....




Here it is drying w/ the VHT High Temp Coating.....
















Here it is installed.............................PERFECT FIT............that made my day great........















This is one of my fav mods......it opened up the mid and HIGH range like no other........4-6K RPM is just crazy......and 1/2 throttle off the line is effortless.....

I will eventually do 2.5" back to the Y and then 2.25 from the Y back w/ mufflers and a rez up in the 2.5"

I thought it would be pointless to do the larger exhaust w/ a DP that is 1.5" in Diam.....so this will open it up a lot when I get the full exhaust on.








Here is the vid of my doing some WOT's and Down shifts..........it is soooooooooooo loud now....I LOVE IT


http://www.youtube.com/watch?v=frqLNcXFZFg

[Superdave]

I can honestly say i've never seen welds like that.. but good job shaping the bends.

[onefastV6]

I can honestly say i've never seen welds like that.. but good job shaping the bends.

Me either, it looks like he smeared JB Weld on the joints and called it a day haha.

This makes me want to order a 2.5" DP for one of my cars now.

[Azrael]

That dual-wall pipe is really misleading. When I had my exhaust done, the guy at the shop convinced me it wasn't worth replacing on the grounds that it "looked" big enough. If only I knew that then.

[AWeb80]

ya the welds are ugly.....but they work...I'm no professional.....never had any instruction...just learned as I went over the years.....


I got better as the day went on...

I had a tendency to blow holes through the pipe, so I had to layer it on thick just to make sure there were no leaks.....LOL

[1meanz]

im no professional but if your blowing holes through it you need to trun the heat down.

[AWeb80]

im no professional but if your blowing holes through it you need to trun the heat down.

I understand that....but, then it was getting too cold and not welding right.....I'm not got at keeping a constant speed either....lol

[19Cutlass94]

looks ugly! but as long as it works the way you need it to I guess thats all that matters!

[94GPGTP]

How long did it take to make it?? I have an extra DP laying around somewhere for the 3100 that i should do this to.. It does sound loud inside the car.. i saw the tach just move like hell from 4-6 then shift.. WOW!! Props to you for doing it yourself!!

Oh and you made that with just them two pipes or did you use more?

Does anyone know what the 3.4 DOHC DP is like?? Is it like the 3100?? I just got 3" Cat back exhaust from d.o.h.c which is being shipped but its like pointless to put it on if the 3.4 DP is like the 3100 DP

[1995 Gold Ciera]

Very cool! I hope to get my car to the shop in the next week to get an estimate on doing a whole exhaust to my 95 Olds (3100 also). I was gonna do 2.5 all the way back.

I wonder what kind of power your DP opened up? I can only imagine what a full exhaust would do. I would guess about 7-10 hp...sorry, just thinking out loud here.

Anywho, why in the hell would GM put such a restrictive system on their cars, yeah it's quieter but man it's like blowing through a frickin' straw!

[AWeb80]

Took me about 6 hrs....the first hr was jacking the car up and figuring out how to get the stock DP off the freaking car...

15mm socket w/ ~16 inches of extensions....

a lot of the time was in the fitting and such....I'd cut a piece, weld it and put it back on to make sure it was going to clear eveything.....only an inch on either side of the DP is all you have for clearance....

took about 45 mins for the spray coating to dry too.....

[Nick-G]

Looking good now thats my kind of welding

[Monzsta]

What year car is that? When I built my 2.5" exhaust I had to install a flex in mine, but I see you have a ball/socket joint made on the manifold end.

If I don't turbo this pig, I may move to that set up next time this flex pipe splits.

[AWeb80]

94 GP

I didn't use a ball/socket on the end, that is a 2.5" to 2" Reducer to fit my stock pipe......I then welded them together....

I will upgrade to 2.5 back soon though....

[ForcedFirebird]

It's OK if you burn holes in the pipe now and again, that just means you need to make bigger cirles to fill it in. Keeping the tip of the wire in the "bubble" can proove difficult. Also when you are welding thin pipe to a thick flange, it helps if you make a "V" groove between the pipe and flange and fill it with the molten wire while favoring the flange side.

Looks like it works well, tough Doesn't have to be pretty to go fast