Almost finished...Almost. - ZR-1 Net Registry Forums

Paul Workman · 05-11-2009

My "entry fee" to the FBI is almost at hand (and I can't wait!!). The porting is done, the engine is back together, sans the plenum and TB (set aside for painting).

Below is the 3" system laid out, ready to be fitted in place...

Per Phil's system, the chambered "mufflers (used as resonators in this experiment) will be fitted between the SW "X" pipe and the muffler links. Those chambered mufflers are a full 3" inside diameter with "cheese shreader" walls.

The only part that isn't 100% 3" is the mufflers...They neck down to 2-1/2" going in. (I wonder if that can't be "opened up to 3").

View from the input side...

And from the output side. Note the twin pipes are just under 2" in diameter. 2 x the square root of the individual diameters results in 2-7/8 "equivalent cross sectional area. Considering a Corsa is 2-1/2" in diameter throughout, AND they seem to make good power, I hoping this necking down at the end of the tail pipe system won't be a big detractor. BUT! everything is on slip fittings, so I can play "mix and match" to get it right.

Last but not least, because I had to have some welding done, the plenum had to be painted. After much deliberation, I decided to try silver. So, I "rattle canned" the intake to get a feel for how it will look when done later professionally. For now, it looks pretty good to a blind man on a galloping horse. So, for this season I'll live with a rattle-can job. (Truth be known, it looks waaay better than the greanish-gray my engine paint has become, over the years). See what you think. (I think it will be a LOT easier to keep clean, especially since I live on a dirt road and dust is a never-ending chore, round here!)

Gettin' so close I can taste it!! The exhaust might "follow on" in a week or so, but "fer sher", barring the unexpected, I'm gonna try to get it fired up.

More later.

P.

LGAFF · 05-11-2009

Paul do you leave that exhaust sitting out in the yard overnight?....if so I need directions to your house.

jonszr1 · 05-11-2009

paul , i doubt that the necking down at the mufflers will cause you any power at all .

-=Jeff=- · 05-12-2009

Paul what are you planning on doing with the Magnaflow X and Resonator?

even though it necks down I may be interested in it

Paul Workman · 05-12-2009

Quote:

Originally Posted by -=Jeff=-

Paul what are you planning on doing with the Magnaflow X and Resonator?

even though it necks down I may be interested in it

Oh, I'll make ya "such a deal" if ya want 'em.

P.

-=Jeff=- · 05-12-2009

Quote:

Originally Posted by Paul Workman

Oh, I'll make ya "such a deal" if ya want 'em.

P.

PM me with details.. that might flow better then the Borla Resonator

XfireZ51 · 05-12-2009

Paul,

Marc H has said more than once that a 2.5" Corsa v. something 3" makes virtually no difference in hp. In fact, I think he's said that it may make more. Similar to the diff between headers at 1 7/8" v 2".

Paul Workman · 05-12-2009

Quote:

Originally Posted by XfireZ51

Paul,

Marc H has said more than once that a 2.5" Corsa v. something 3" makes virtually no difference in hp. In fact, I think he's said that it may make more. Similar to the diff between headers at 1 7/8" v 2".

Yes, Marc and I touched on this a bit. I wouldn't dispute anything Marc says

However, what is not clear to me is "why"? And, from Marc's web site, he compares the Corsa 2-1/2 with the B&B 3" and points out a couple possible reasons why the B&B might suffer in spite of the larger size, overall.
For example, he show how the new B&B muffler is significantly baffled, AND the resonator pipes are 1.625 in diameter

(This might be why you didn't see any significant power loss when switching to the Magnaflow, as at least the resonator AND the mufflers appear to be much more open in those respects than the B&B, no?)

http://www.zr1specialist.com/HAT%20W...20vs%20b&b.htm

So, I don't know if we're comparing apples to apples between the Corsa and B&B. It would appear the Corsa is hands down more open from end to end that the B&B, especially at the resonator! So, extrapolating a bit, if the Corsa does in fact result in more hp due to less actual restriction, then maybe a little less would be even better...Maybe. I'm hoping the dyno can shed some light on it.

P.

DMark · 05-12-2009

Quote:

Originally Posted by Paul Workman

..... I live on a dirt road.....

05-11-2009	#1
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Almost finished...Almost. My "entry fee" to the FBI is almost at hand (and I can't wait!!). The porting is done, the engine is back together, sans the plenum and TB (set aside for painting). Below is the 3" system laid out, ready to be fitted in place... Per Phil's system, the chambered "mufflers (used as resonators in this experiment) will be fitted between the SW "X" pipe and the muffler links. Those chambered mufflers are a full 3" inside diameter with "cheese shreader" walls. The only part that isn't 100% 3" is the mufflers...They neck down to 2-1/2" going in. (I wonder if that can't be "opened up to 3"). View from the input side... And from the output side. Note the twin pipes are just under 2" in diameter. 2 x the square root of the individual diameters results in 2-7/8 "equivalent cross sectional area. Considering a Corsa is 2-1/2" in diameter throughout, AND they seem to make good power, I hoping this necking down at the end of the tail pipe system won't be a big detractor. BUT! everything is on slip fittings, so I can play "mix and match" to get it right. Last but not least, because I had to have some welding done, the plenum had to be painted. After much deliberation, I decided to try silver. So, I "rattle canned" the intake to get a feel for how it will look when done later professionally. For now, it looks pretty good to a blind man on a galloping horse. So, for this season I'll live with a rattle-can job. (Truth be known, it looks waaay better than the greanish-gray my engine paint has become, over the years). See what you think. (I think it will be a LOT easier to keep clean, especially since I live on a dirt road and dust is a never-ending chore, round here!) Gettin' so close I can taste it!! The exhaust might "follow on" in a week or so, but "fer sher", barring the unexpected, I'm gonna try to get it fired up. More later. P.

05-11-2009	#2
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,180	Re: Almost finished...Almost. Paul do you leave that exhaust sitting out in the yard overnight?....if so I need directions to your house. __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

05-11-2009	#3
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,406	Re: Almost finished...Almost. paul , i doubt that the necking down at the mufflers will cause you any power at all .

05-12-2009	#4
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,156	Re: Almost finished...Almost. Paul what are you planning on doing with the Magnaflow X and Resonator? even though it necks down I may be interested in it __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Shelby Series 1 - Wilwood Brakes Custom Interior NCM Lifetime Member #978

05-12-2009	#7
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,683	Re: Almost finished...Almost. Paul, Marc H has said more than once that a 2.5" Corsa v. something 3" makes virtually no difference in hp. In fact, I think he's said that it may make more. Similar to the diff between headers at 1 7/8" v 2".