if i was to get a 3.73 rear end, with my 700R4 with the .7 OD gear on stock 26" tires, i should easily be able to hit a 100 mph trap speed right? according to my calculations, that combo should be good up to about 110mpg, right? i dont want to over gear(under gear?) my car to the point that it wont hit 100 (MAYBE eventually 105) in the 1/4.

according to what i figured out, theoretically (with drag accounted for) with 3.73s, at 5500 rpm, my top speed should still be 136. also, with this combo, if i was to cross the line at 100mph, i should be spinning 4,000rpm. at 110mph, i would be spinning 4,400rpm.

now i know you are gonna ask how the hell i figured this out...well i used math formulas and i figured out the drag..blah blah blah. anyways...i figured it out to be VERY accurate. i have tested my calculations at a lot off diffrenet gears and different speeds, so i know them to be almost exactly right.


I am not asking if my mods will put me at 100 mph in the 1/4, i am asking if it is theoretically possible. thanks a lot.
-Brian

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1991 Camaro RS
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Ultra Blue Metallic, T-Tops

GM 350 HO Crate Engine - Vortec Heads, Edelbrock Performer Vortec Intake, Holley 670 CFM Throttle Body, Open Air Cleaner w/14"x3" K&N, SLP 1 3/4" Stainless Headers, Edelbrock Victor Series Water Pump, Accell Superstock Wires, Cap, and Rotor, MSD Blaster Coil, Hypertech Fan Switch & Thermomaster Chip, AC Delco Rapidfires, 3" Cat Back, Flowmaster 40 Series Muffler

700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler

Brian's 1991 RS

Central NY F-Body Association

z28boy@twcny.rr.com IM name: Z28 Boy

[This message has been edited by Z28 Boy (edited November 01, 2000).]

[This message has been edited by Z28 Boy (edited November 01, 2000).]

 

Well you shouldn't even be leaving 3rd gear in a 1/4 mile run. 3rd should be good up to around 120mph, so you should be fine.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

supposed 'peanut cammed' car (yeah, right)

Built on Wednesday

 

Your trap speed is determined more by your engine's horsepower. Your gearing has more to do with your ET.

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1984 Silver Z28, 383 cid 4 bolt, ARP Fasteners, 2 1/2" Cowl Induction Hood, 600 cfm Performer Carburetor, Torker II Intake, Performer RPM Heads, XE268H Cam, Magnum Roller Tip Rockers, MSD6AL Ignition, Blaster2 Coil, Recurved HEI Distributor, 700R4, TransGo SK, 2.73:1 Limited Slip Dana 44, Terminator Headers, Custom 3" TIG Welded Stainless Exhaust, Flowmaster Muffler, 4 Wheel Disc Brakes, Oil Cooler

 

yeah but with 3.73s, my top speed in third (at about 5500rpm) will only be about 95. I doubt that my trap speed will be much higher than that anyways, but I just want to make sure hat I shouldn't go with 3.42s. They will give me a tops speed in 3rd of like 105.
-brian

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1991 Camaro RS
----------------------------------------------
Ultra Blue Metallic, T-Tops

GM 350 HO Crate Engine - Vortec Heads, Edelbrock Performer Vortec Intake, Holley 670 CFM Throttle Body, Open Air Cleaner w/14"x3" K&N, SLP 1 3/4" Stainless Headers, Edelbrock Victor Series Water Pump, Accell Superstock Wires, Cap, and Rotor, MSD Blaster Coil, Hypertech Fan Switch & Thermomaster Chip, AC Delco Rapidfires, 3" Cat Back, Flowmaster 40 Series Muffler

700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler

Brian's 1991 RS

Central NY F-Body Association

z28boy@twcny.rr.com IM name: Z28 Boy

 

Are you sure you have worked this out correctly? I have 3.73s and 26.5 tires and I am at about 4700 at 100mph.


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Cosmik Debris

 

****, my '84 hit 135 mph with 3.73s and 27" (235/65/15) diameter tires in third gear (TH700-R4) at about 6250 rpms.

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George P. Lara
1994 Z28 LT1 T56
1984 Z28 High Output
Member: SCCA, SCFB, SC3GFB

 

i'm pretty sure that i have it worked out right. i mean it is really accurate as far as my car goes...i can usually get it within a hundred rpms.

wow...6250 and 135 with 3.73s in 3rd? maybe i am a little off...but i really dont think so. i doubt that that little difference in tire size will throw the numbers off by that much. oh well..i still have some homework to do as far as all these calculations go...but it looks like 3.73s will be fine.
-brian

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1991 Camaro RS
----------------------------------------------
Ultra Blue Metallic, T-Tops

GM 350 HO Crate Engine - Vortec Heads, Edelbrock Performer Vortec Intake, Holley 670 CFM Throttle Body, Open Air Cleaner w/14"x3" K&N, SLP 1 3/4" Stainless Headers, Edelbrock Victor Series Water Pump, Accell Superstock Wires, Cap, and Rotor, MSD Blaster Coil, Hypertech Fan Switch & Thermomaster Chip, AC Delco Rapidfires, 3" Cat Back, Flowmaster 40 Series Muffler

700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler

Brian's 1991 RS

Central NY F-Body Association

z28boy@twcny.rr.com IM name: Z28 Boy

 

ALRIGHT ALREADY!!!!! TIME TO PUT THIS TO REST!!!!

I run 26" slicks with 3.73's and a TCI competition 700R-4 without lockup and I run through the traps at 105MPH at 5300 RPM, check my sig. I have a crap load of timeslips documenting these results so the argument is over. Math is great but there is no substitute for a timeslip and a tach!

Any questions, class is in session.

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

91 Firebird 5.0L TBI

ASE Certified CHEVY DEALER Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

Oh, by the way (FYI) in fourth without lockup I can do 143MPH at 4400RPM.

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

91 Firebird 5.0L TBI

ASE Certified CHEVY DEALER Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

Actually that is correct. Remember I was turning 6250 rpms and 27" tall tires and you are comparing 5500 rpms with 26" tall tires. How are you calculating the top speed in third? You're equation is definately off. I calculated 115 at 5500 rpms using 26" tires in third. So far all the other 3.73 examples are supporting this.

 

yeah i see what you are saying, but isnt there a certain amount of drag that will make the calculated speeds a little lower?

here is the equation to use for a perfect situation (no friction, and all that other crap)..

[(RPM/GEAR RATIO)]*[(CIRC.)/(12)]*[(60)/5280)]

as far as the drag goes, i figured it out this way...

knowing what my gear ratios are, blah blah blah, and getting the actual speed, i figured out the % difference which usually turned out to be about 10%.

is there actually a difference? i mean, there has to be some difference. oh well. i dunno..i guess that after all of this, i realize one thing...(correct me if i am wrong)...

with 26" tires, and 3.73s, my trap speed could theoretically be at least 105mph, in third gear, at (or below)5500rpm. i dont really care too much past that because i wont be going that fast with my setup.

thanks to everyone that helped...

-brian

------------------
1991 Camaro RS
----------------------------------------------
Ultra Blue Metallic, T-Tops

GM 350 HO Crate Engine - Vortec Heads, Edelbrock Performer Vortec Intake, Holley 670 CFM Throttle Body, Open Air Cleaner w/14"x3" K&N, SLP 1 3/4" Stainless Headers, Edelbrock Victor Series Water Pump, Accell Superstock Wires, Cap, and Rotor, MSD Blaster Coil, Hypertech Fan Switch & Thermomaster Chip, AC Delco Rapidfires, 3" Cat Back, Flowmaster 40 Series Muffler

700R4 - 2,400 Stall Converter, Vette Servo, Shift Kit, B&M Super Cooler

Brian's 1991 RS

Central NY F-Body Association

z28boy@twcny.rr.com IM name: Z28 Boy

[This message has been edited by Z28 Boy (edited November 03, 2000).]

 

Drag doesn't affect what the final drive ratio, transmission gear ratio, engine rpm, and tire diameter will calculate to. Drag affects how HIGH your engine can rev up in the given gear (1st, 2nd, 3rd, 4th). Plus as the ratios between the transmission gears change, so does the amount torque available the engine needs to push the vehicle down the road. Example: going 40 mph in 2nd (1.63), your car will accelarate faster than if it was in 4th (.70). Provided you could hold 4th without the trans downshifting. That is where drag comes in, how high the potential rpms will be.

[This message has been edited by MRZ28HO (edited November 03, 2000).]