Pete's 1/4 times: 3.45@GLD vs. 4.10@BG - ZR-1 Net Registry Forums

Paul Workman · 01-29-2012

Just an observation:

Pete (in the electric water pump thread) provided his 11.04 & 11.09 sec times at GLD (Great Lakes Dragway) were with his 3.45 ratio differential. And, if I recall correctly, Pete ran an 11.0 "something" (Pete pls correct me) at BG with the 4.10 gear.

Well, the thing that leaps out at me is the ETs were practically the same, yet the weather and gear circumstances were signifcantly different.

Just trying to get a feeling for the effect the weather conditons might have had on Pete's horsepower, I took the liberty of estimating the conditons for each the GLD and BG runs and plugged them into one of the popular calculators, typical of the kind used on dynos.

Using the following:

GLD:

altitude = 600 ft AMSL
temp = 40F
Hg = 29.0
Dew Pt = 30F

Relative HP = 100%
DA = 615'

For BG:

altitude = 547 ft AMSL (at the airport)
temp = 80F
Hg = 29.0
Dew Pt = 60F

Relative HP = 94.4%
DA = 3306'

SO! Relative to the discussion about the difference between quarter mile times with a 3.45 vs. a 4.10 gear (which comes around more times here than a carousel pony), it would appear Pete's 4.10 gear overcame a 5.6% effective HP loss (due to conditions).

OK, one datum (BG) does not a trend make, but isn't it interesting that the ETs were so close - hell, practically the same - when Pete's motor was producing something like 27* rwhp LESS at BG than it did at GLC.

Some claim little or no practical ET difference between the 3.45 vs. the 4.10 gear in the quarter; usually centering around loss due to the extra shift. The debate will go on I'm sure. But, these results of Pete's intrigues me. All things are held as close to common as possible, far as car and driver experience goes. Yet the ETs are pratically the same in spite of significant differences in conditions at the track. It suggests there IS a difference - a difference in favor of the 4.10s, - just like Bob G (aka Gillig Racing) recommends for the 350 ci ZR-1s.

Yeah, bench racing... But, what the heck...It's snowing outside, and I'm having ZR-1 withdrawals!!

P.

01-29-2012	#1
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Pete's 1/4 times: 3.45@GLD vs. 4.10@BG Just an observation: Pete (in the electric water pump thread) provided his 11.04 & 11.09 sec times at GLD (Great Lakes Dragway) were with his 3.45 ratio differential. And, if I recall correctly, Pete ran an 11.0 "something" (Pete pls correct me) at BG with the 4.10 gear. Well, the thing that leaps out at me is the ETs were practically the same, yet the weather and gear circumstances were signifcantly different. Just trying to get a feeling for the effect the weather conditons might have had on Pete's horsepower, I took the liberty of estimating the conditons for each the GLD and BG runs and plugged them into one of the popular calculators, typical of the kind used on dynos. Using the following: GLD: altitude = 600 ft AMSL temp = 40F Hg = 29.0 Dew Pt = 30F Relative HP = 100% DA = 615' For BG: altitude = 547 ft AMSL (at the airport) temp = 80F Hg = 29.0 Dew Pt = 60F Relative HP = 94.4% DA = 3306' SO! Relative to the discussion about the difference between quarter mile times with a 3.45 vs. a 4.10 gear (which comes around more times here than a carousel pony), it would appear Pete's 4.10 gear overcame a 5.6% effective HP loss (due to conditions). OK, one datum (BG) does not a trend make, but isn't it interesting that the ETs were so close - hell, practically the same - when Pete's motor was producing something like 27* rwhp LESS at BG than it did at GLC. Some claim little or no practical ET difference between the 3.45 vs. the 4.10 gear in the quarter; usually centering around loss due to the extra shift. The debate will go on I'm sure. But, these results of Pete's intrigues me. All things are held as close to common as possible, far as car and driver experience goes. Yet the ETs are pratically the same in spite of significant differences in conditions at the track. It suggests there IS a difference - a difference in favor of the 4.10s, - just like Bob G (aka Gillig Racing) recommends for the 350 ci ZR-1s. Yeah, bench racing... But, what the heck...It's snowing outside, and I'm having ZR-1 withdrawals!! P. Last edited by Paul Workman; 01-29-2012 at 10:03 AM.