Took my 91 ZR-1 to the dyno today - Page 2 - ZR-1 Net Registry Forums

Ccmano · 09-05-2018

If that’s a DRM475 I would be hugely disappointed in 371rwhp. A 475hp motor should have 400rwhp.
H

Neat · 09-06-2018

It is a DRM 475 car. However, it's missing the headers that normally come with that package. I'm not sure how much power is being left on the table by continuing to use the stock exhaust manifolds.

The dyno numbers were about what I expected, and certainly not a huge disappointment, lol. It would interest me to install some headers and do the dyno test again. I'm curious how much (if any) stock manifolds are costing me. Maybe that'll be the next "to do" thing for the car.

efnfast · 09-06-2018

I would think headers would get you to about where Hans expects you to be.

ZWILD1 · 09-06-2018

I was surprised to see that your car is the same color exterior and interior as mine. Plus I just installed the chrome five spokes about a week ago with BFG drag radials and the BFG Comp II summer tread up front. Mine was done by Mark Haibeck with the 525 package so there is no limiting the power via the Valet key. It's not like my first 91 that had headers , no cats, B&B 3in exhaust , and 4.10 gears. It still delivered descent gas mileage with the secondary actuators still working. With the Haibeck 525 package when you stomp on it you can almost see the fuel gauge go down, lol.

jss06c6 · 09-07-2018

Quote:

Originally Posted by Neat

It is a DRM 475 car. However, it's missing the headers that normally come with that package. I'm not sure how much power is being left on the table by continuing to use the stock exhaust manifolds.

The dyno numbers were about what I expected, and certainly not a huge disappointment, lol. It would interest me to install some headers and do the dyno test again. I'm curious how much (if any) stock manifolds are costing me. Maybe that'll be the next "to do" thing for the car.

Assuming a proper tune, I would suspect about 25-35 WHP loss by using the stock exhaust manifolds. They are severely pinched at the collector and definitely a source of exhaust restriction.

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09-05-2018	#11
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,843	Re: Took my 91 ZR-1 to the dyno today If that’s a DRM475 I would be hugely disappointed in 371rwhp. A 475hp motor should have 400rwhp. H __________________ [B]90'ZR-1[/B] #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold [B]08 C6 Z51[/B] Crystal Red Metallic Sold Vararam Intake, Tune, Sold [B]05 C6 Z51[/B] Red/Black Sold [B]90'ZR-1[/B] #1723 Black/Gray Sold but not forgotten [B]91' Z51 L98[/B] White Vert. My First, you always remember your first. Sold.

09-06-2018	#12
Neat Join Date: Apr 2018 Location: Raleigh, NC Posts: 41	Re: Took my 91 ZR-1 to the dyno today It is a DRM 475 car. However, it's missing the headers that normally come with that package. I'm not sure how much power is being left on the table by continuing to use the stock exhaust manifolds. The dyno numbers were about what I expected, and certainly not a huge disappointment, lol. It would interest me to install some headers and do the dyno test again. I'm curious how much (if any) stock manifolds are costing me. Maybe that'll be the next "to do" thing for the car. __________________ 1991 ZR-1 #769 - Turquoise / black - DRM 475 - 12.2 @ 121 - 1993 Mustang - White / Black - 5.3 Chevrolet Engine - Twin Turbos - Other Stuff - 8.62 @ 156 -

09-06-2018	#13
efnfast Join Date: Nov 2011 Location: Dunbarton NH Posts: 7,540	Re: Took my 91 ZR-1 to the dyno today I would think headers would get you to about where Hans expects you to be.