Trap speed question - ZR-1 Net Registry Forums

9T1 Red ZR1 · 11-11-2015

What trap speed would you expect from a completely stock 1991 ZR-1 in a 1400 foot roll race with a 55 mph starting speed?

Thanks,
Bill

Bob Eyres · 11-15-2015

My guess is about 130 mph.

Real racers go from a dig. A stock 91' will do 107-110 from a standing start in the 1/4 mi. which is 80ft. shorter than your race.

There are too many variables to accurately predict. So, did you try it?

9T1 Red ZR1 · 11-15-2015

Hi,
I did try it, my speed ranged from 115 to 118 on 5 runs. I didn't miss any shifts or anything like that. The car felt strong in first and second, third felt OK, but I don't know since I never run that fast on the street. I thought it was a little slow. I have new injectors, plugs, coils and wires installed. I will have to check my fuel pressure. I can't test it now, my alternator went out as I was 1 mile from my house on the way home. Thanks for your response.
Bill

JFFerner · 11-16-2015

Did you really try to accelerate from a 55 mph starting speed in first gear?

9T1 Red ZR1 · 11-16-2015

No, there was a 240 foot run up to the start line. For the run to count, you had to be at 55 mph plus or minus 5 mph. I was in second at the start line when I opened it up wide open. It was a little tricky not going too fast at the start, but I wasn't real happy with my speed at the end. I'm not sure if I was losing power. When I turn my key on, the vacuum pump only runs for a few seconds, then stays off for about 45 seconds so I think my secondaries were working OK. I was just shifting into 4th by the end, shifting at an indicated 7000 rpm.

vilant · 11-16-2015

I've read before about power loss due to heat soak from the engine. That's why some have they're air temp sensor moved off the air horn and have the radiator fans come on at lower temps. Is your tach calibrated? You can check through the AC display.

9T1 Red ZR1 · 11-16-2015

Those are good suggestions, I will look into that. Thanks, Joe.

Bill

vilant · 11-16-2015

No problem. Forgot to mention, if you still have the original accordion between the filter and air horn and you don't have Marc's rings in there, the accordion could be collapsing under load and restricting air flow. Get the rings or a Samco duct, depending if you like the original look or not. I have the rings.

9T1 Red ZR1 · 11-16-2015

Joe, It's funny that you mentioned those rings. I was on Marc's site and saw them as well as a new chip that has calibration to deal with engine heat. Very good advice.

Thanks,
Bill

Bob Eyres · 11-20-2015

What was the ambient temp when you were running? I wouldn't think you'd have much of a heat problem in Pa. at this time of year.

11-11-2015	#1
9T1 Red ZR1 Join Date: Jun 2013 Location: Warminster, PA Posts: 78	Trap speed question What trap speed would you expect from a completely stock 1991 ZR-1 in a 1400 foot roll race with a 55 mph starting speed? Thanks, Bill __________________ LT5 Red/Red

11-15-2015	#2
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Re: Trap speed question My guess is about 130 mph. Real racers go from a dig. A stock 91' will do 107-110 from a standing start in the 1/4 mi. which is 80ft. shorter than your race. There are too many variables to accurately predict. So, did you try it?

11-15-2015	#3
9T1 Red ZR1 Join Date: Jun 2013 Location: Warminster, PA Posts: 78	Re: Trap speed question Hi, I did try it, my speed ranged from 115 to 118 on 5 runs. I didn't miss any shifts or anything like that. The car felt strong in first and second, third felt OK, but I don't know since I never run that fast on the street. I thought it was a little slow. I have new injectors, plugs, coils and wires installed. I will have to check my fuel pressure. I can't test it now, my alternator went out as I was 1 mile from my house on the way home. Thanks for your response. Bill __________________ LT5 Red/Red

11-16-2015	#4
JFFerner Join Date: Jan 2012 Location: Dallastown, PA Posts: 189	Re: Trap speed question Did you really try to accelerate from a 55 mph starting speed in first gear?

11-16-2015	#5
9T1 Red ZR1 Join Date: Jun 2013 Location: Warminster, PA Posts: 78	Re: Trap speed question No, there was a 240 foot run up to the start line. For the run to count, you had to be at 55 mph plus or minus 5 mph. I was in second at the start line when I opened it up wide open. It was a little tricky not going too fast at the start, but I wasn't real happy with my speed at the end. I'm not sure if I was losing power. When I turn my key on, the vacuum pump only runs for a few seconds, then stays off for about 45 seconds so I think my secondaries were working OK. I was just shifting into 4th by the end, shifting at an indicated 7000 rpm. __________________ LT5 Red/Red

11-16-2015	#6
vilant Join Date: Jun 2012 Location: PA Posts: 772	Re: Trap speed question I've read before about power loss due to heat soak from the engine. That's why some have they're air temp sensor moved off the air horn and have the radiator fans come on at lower temps. Is your tach calibrated? You can check through the AC display. __________________ Joe 1990 Bright Red ZR-1 #2599

11-16-2015	#7
9T1 Red ZR1 Join Date: Jun 2013 Location: Warminster, PA Posts: 78	Re: Trap speed question Those are good suggestions, I will look into that. Thanks, Joe. Bill __________________ LT5 Red/Red

11-16-2015	#8
vilant Join Date: Jun 2012 Location: PA Posts: 772	Re: Trap speed question No problem. Forgot to mention, if you still have the original accordion between the filter and air horn and you don't have Marc's rings in there, the accordion could be collapsing under load and restricting air flow. Get the rings or a Samco duct, depending if you like the original look or not. I have the rings. __________________ Joe 1990 Bright Red ZR-1 #2599

11-16-2015	#9
9T1 Red ZR1 Join Date: Jun 2013 Location: Warminster, PA Posts: 78	Re: Trap speed question Joe, It's funny that you mentioned those rings. I was on Marc's site and saw them as well as a new chip that has calibration to deal with engine heat. Very good advice. Thanks, Bill __________________ LT5 Red/Red

11-20-2015	#10
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 815	Re: Trap speed question What was the ambient temp when you were running? I wouldn't think you'd have much of a heat problem in Pa. at this time of year. __________________ "It's about the car, not the people." 1991 ZR-1 White/Black #1236 (Owner since 1994). Stock engine with bolt-ons: Hurst shifter,"Forced Air" intake, Coplon duct, Bee Cool Radiator, Demon coils, Jeal prom, Watson headers, X pipe, 3" B&B's, Rippie flywheel, 4:10 gears, A molds, Toyo Proxes-R888's 12.06@117mph. 1.76 60ft.