Found my HP problem - Page 2 - ZR-1 Net Registry Forums

Ccmano · 07-12-2009

Thanks for the input guys. As we know not all dynos are equal or accurate for that mater. I suspect this one was not real accurate. In this case, same day same dyno, karterdon put down 358/349 on his 91'. He has similar mods but no headers and is using a full Corsa cat back. So this gives me a point of reference. I have headers and the modded Corsa, but only 10 more HP?

As for my mods, I do not have any head work other than port matching the IH's and the cams have not been timed. Based on several other cars I've seen numbers on, with the same mods, I should be in the 385 to 395HP area.

Paul can you give me the dimensions of that magnaflow resonator you have? Length, width, height and most importantly what is the center to center distance of the piping going in and out. Thanks

H

LGAFF · 07-12-2009

Check this site for options:

http://www.magnaflow.com/02product/u...asp?shape=oval

LGAFF · 07-12-2009

Wonder if this glasspack resonator might work: http://www.classicchambered.com/classic/products.html

Ccmano · 07-12-2009

Paul,

Is that Magnflow resonator out of a Kit or is it just a standard Magnaflow part?

H

-=Jeff=- · 07-12-2009

Quote:

Originally Posted by Ccmano

Paul,

Is that Magnflow resonator out of a Kit or is it just a standard Magnaflow part?

H

his is the one out of the LT4 kit.. Same center section Dominic has on his car

Paul Workman · 07-12-2009

Sorry it took so long to get back, but "duty called", and I had to go in to start one of the crews this morning. (Y'all sleep in WAAAAAY to late anyway!!

)

But, Jeff is right: It is part of an LT4 kit. I kept the mufflers (installed yesterday), but I was looking to "go for performance" first, and then back off (if necessary) for ride comfort. (Right now it has the SWs w/ 3" outlets to a SW X (more like a "merge") pipe to Magnaflow links and mufflers. I need the assistance of someone that can cut and weld stainless tubing so as to install my "Power Stick" "resonators"...Al? Whatcha doin' buddy???.)

P.

XfireZ51 · 07-12-2009

Hans,

If you do decide to try the MFlow system, I'd suggest going to Twisted Pipes. It will take a little work to match the header collector to the
X-pipe, particularly on the passenger side, as there was a slight offset with the Watsons I have.
As for dynos, I week before Bowling Green, I went to Street Stuff and dyno'd the head porting and headers I did. 385rwhp. In BG both Don and I put ours on and I dyno'd 370rwhp. SO to your point re: dynos.
My first suggestion would be to dyno the car as is at a known shop and scan it to eliminate other factors being the culprit for your power loss.
We could even look at tuning it to see if output could be optimized.
Then I'd look at addressing the exhaust if it still isn't performing to expectations. My $.02

LGAFF · 07-12-2009

I would say the 2" stuff needs to go before going to any dyno, think tf95ZR1 could chime in, I can't recall what he picked up when he dumped the Borla resonator but if I recall over 15hp...and it necks to about 2.25"

XfireZ51 · 07-12-2009

Quote:

Originally Posted by LGAFF

I would say the 2" stuff needs to go before going to any dyno, think 95ZR1 could chime in, I can't recall what he picked up when he dumped the Borla resonator but if I recall over 15hp...and it necks to about 2.25"

I would disagree because I believe you would want to establish a benchmark you can measure against as needed. The one in Antioch
wouldn't be something I would depend on replicating. I'm not disagreeing that the exhaust could represent a restriction, but is it the only thing? Is it responsible for 15-20rwhp? I don't think any of us knows that at this point.

rhipsher · 07-12-2009

Personally from my own experiance going from the Borla resonater to straight 2.5 dia pipes in place of it I didn't notice any difference at all in power. At least nothing I could physically feel. Of course I still had the Borla mufflers on it. There was no resonence running with straight pipes. But the exhuast tone sounded like crap and I couldn't wait to put the Borla res back on. Maybe and X pipe would have made a difference. I don't know.

07-12-2009	#11
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Found my HP problem Thanks for the input guys. As we know not all dynos are equal or accurate for that mater. I suspect this one was not real accurate. In this case, same day same dyno, karterdon put down 358/349 on his 91'. He has similar mods but no headers and is using a full Corsa cat back. So this gives me a point of reference. I have headers and the modded Corsa, but only 10 more HP? As for my mods, I do not have any head work other than port matching the IH's and the cams have not been timed. Based on several other cars I've seen numbers on, with the same mods, I should be in the 385 to 395HP area. Paul can you give me the dimensions of that magnaflow resonator you have? Length, width, height and most importantly what is the center to center distance of the piping going in and out. Thanks H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

07-12-2009	#12
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Found my HP problem Check this site for options: http://www.magnaflow.com/02product/u...asp?shape=oval __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

07-12-2009	#13
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Found my HP problem Wonder if this glasspack resonator might work: http://www.classicchambered.com/classic/products.html __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

07-12-2009	#14
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Found my HP problem Paul, Is that Magnflow resonator out of a Kit or is it just a standard Magnaflow part? H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

07-12-2009	#16
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: Found my HP problem Sorry it took so long to get back, but "duty called", and I had to go in to start one of the crews this morning. (Y'all sleep in WAAAAAY to late anyway!!) But, Jeff is right: It is part of an LT4 kit. I kept the mufflers (installed yesterday), but I was looking to "go for performance" first, and then back off (if necessary) for ride comfort. (Right now it has the SWs w/ 3" outlets to a SW X (more like a "merge") pipe to Magnaflow links and mufflers. I need the assistance of someone that can cut and weld stainless tubing so as to install my "Power Stick" "resonators"...Al? Whatcha doin' buddy???.) P. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry

07-12-2009	#17
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Found my HP problem Hans, If you do decide to try the MFlow system, I'd suggest going to Twisted Pipes. It will take a little work to match the header collector to the X-pipe, particularly on the passenger side, as there was a slight offset with the Watsons I have. As for dynos, I week before Bowling Green, I went to Street Stuff and dyno'd the head porting and headers I did. 385rwhp. In BG both Don and I put ours on and I dyno'd 370rwhp. SO to your point re: dynos. My first suggestion would be to dyno the car as is at a known shop and scan it to eliminate other factors being the culprit for your power loss. We could even look at tuning it to see if output could be optimized. Then I'd look at addressing the exhaust if it still isn't performing to expectations. My $.02

07-12-2009	#18
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: Found my HP problem I would say the 2" stuff needs to go before going to any dyno, think tf95ZR1 could chime in, I can't recall what he picked up when he dumped the Borla resonator but if I recall over 15hp...and it necks to about 2.25" __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 Last edited by LGAFF; 07-12-2009 at 11:01 PM.

07-12-2009	#20
rhipsher Join Date: Aug 2008 Location: Houston 90 Red ZR-1 Posts: 2,320	Re: Found my HP problem Personally from my own experiance going from the Borla resonater to straight 2.5 dia pipes in place of it I didn't notice any difference at all in power. At least nothing I could physically feel. Of course I still had the Borla mufflers on it. There was no resonence running with straight pipes. But the exhuast tone sounded like crap and I couldn't wait to put the Borla res back on. Maybe and X pipe would have made a difference. I don't know.