pre dyno pull question - ZR-1 Net Registry Forums

ghlkal · 07-18-2013

Now that I have #2180 running well (at least I think I do), I want to do a base line dyno pull before I do any mods.

The local place has a Mustang dyno, and like pushrod was, I’m hoping for about 320rwhp (375crank * .85). If I got numbers like pushrod did, I’d be very happy (see http://www.zr1.net/forum/showthread.php?t=20712)

The shop said I should have AF measured during the run. I don’t think that’s necessary since this isn’t a dyno tune. They’d have to weld a bung in (and charge for that), but once I replace the manifolds with headers, that would be useless.

So here’s my question – is there any reason to have AF measured during the dyno pull? (What haven’t I considered?)

Thanks

Jagdpanzer · 07-18-2013

If you are going with headers no need to do an AF now.
Spend your money on a good dyno tune after the mods.

GOLDCYLON · 07-18-2013

Quote:

Originally Posted by Jagdpanzer

If you are going with headers no need to do an AF now.
Spend your money on a good dyno tune after the mods.

Agreed

Karl · 07-18-2013

During my dyno run they didn't connect a a/f meter which was fine with me.

Good luck and record a video!

LGAFF · 07-18-2013

should have a pipe sniffer they can stick in the end

XfireZ51 · 07-18-2013

I want a WB on any dyno run I do simply to make sure it isn't getting lean at WOT. Whenever I have done tuning, I baseline the car and tell the operator to get out of the throttle if he sees AFR going above say 13.4-13.5. Surprised they don't have a WB that simply fits into the tailpipe. I would agree that the bung on the collector is more accurate. My ZT-2 is located there and I have compared readings from it to the one at the dyno shop. I know where my WB has been and you don't really know what motors or fuels have been used w the dyno shop WB. But better safe than sorry IMO. Stock motor and stock calibration, its likely WOT will be rich which isn't a problem. But these are 20+ year old cars.

ghlkal · 07-19-2013

Thanks for the feedback y'all.

I agree with LGAFF and XfireZ51 that I wouldn't want the engine to go lean at WOT. I'm hoping they can test via a tail pipe probe. But, if not I'm not going to add a bung and pay extra for the wideband monitoring.

I'll let you know how it goes.

Karl · 07-19-2013

Dont get me wrong, i'de prefer a wideband too but considering my car is stock and I've beat on it plenty of times I felt good about my run.

My headers will have a extra o2 bung for dyno tuning. Next time my car see's a dyno it will be modified and not stock so o2 monitoring will be necessary.

XfireZ51 · 07-20-2013

There shouldn't be any reason to add a bung when going to a dyno. Never run into a dyno shop without a tailpipe sniffer.

07-18-2013	#1
ghlkal Join Date: Jan 2012 Location: Wisconsin Posts: 887	pre dyno pull question Now that I have #2180 running well (at least I think I do), I want to do a base line dyno pull before I do any mods. The local place has a Mustang dyno, and like pushrod was, I’m hoping for about 320rwhp (375crank * .85). If I got numbers like pushrod did, I’d be very happy (see http://www.zr1.net/forum/showthread.php?t=20712) The shop said I should have AF measured during the run. I don’t think that’s necessary since this isn’t a dyno tune. They’d have to weld a bung in (and charge for that), but once I replace the manifolds with headers, that would be useless. So here’s my question – is there any reason to have AF measured during the dyno pull? (What haven’t I considered?) Thanks

07-18-2013	#4
Karl Join Date: May 2013 Location: Chicago Posts: 980	Re: pre dyno pull question During my dyno run they didn't connect a a/f meter which was fine with me. Good luck and record a video! __________________ 1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black Sold 1985 L98 Blue On Blue Sold

07-18-2013	#5
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: pre dyno pull question should have a pipe sniffer they can stick in the end __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

07-18-2013	#6
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: pre dyno pull question I want a WB on any dyno run I do simply to make sure it isn't getting lean at WOT. Whenever I have done tuning, I baseline the car and tell the operator to get out of the throttle if he sees AFR going above say 13.4-13.5. Surprised they don't have a WB that simply fits into the tailpipe. I would agree that the bung on the collector is more accurate. My ZT-2 is located there and I have compared readings from it to the one at the dyno shop. I know where my WB has been and you don't really know what motors or fuels have been used w the dyno shop WB. But better safe than sorry IMO. Stock motor and stock calibration, its likely WOT will be rich which isn't a problem. But these are 20+ year old cars. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

07-19-2013	#7
ghlkal Join Date: Jan 2012 Location: Wisconsin Posts: 887	Re: pre dyno pull question Thanks for the feedback y'all. I agree with LGAFF and XfireZ51 that I wouldn't want the engine to go lean at WOT. I'm hoping they can test via a tail pipe probe. But, if not I'm not going to add a bung and pay extra for the wideband monitoring. I'll let you know how it goes.

07-18-2013	#2
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,661	Re: pre dyno pull question If you are going with headers no need to do an AF now. Spend your money on a good dyno tune after the mods. __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake

07-19-2013	#8
Karl Join Date: May 2013 Location: Chicago Posts: 980	Re: pre dyno pull question Dont get me wrong, i'de prefer a wideband too but considering my car is stock and I've beat on it plenty of times I felt good about my run. My headers will have a extra o2 bung for dyno tuning. Next time my car see's a dyno it will be modified and not stock so o2 monitoring will be necessary. __________________ 1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black Sold 1985 L98 Blue On Blue Sold Last edited by Karl; 07-19-2013 at 11:58 PM.

07-20-2013	#9
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: pre dyno pull question There shouldn't be any reason to add a bung when going to a dyno. Never run into a dyno shop without a tailpipe sniffer. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX