A6 gears for FI - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

brantley847 · 08-19-2012, 08:17 PM

I am attempting to build a foundation for my auto to go FI in the next year or so... Obviously, many of you have experience with this so my question asthe subject suggests is what ratio is best for not only an A6 but to build me the foundation to eventually go FI.

I was set on the 3.70-3.73 but it is hard to ignore the 3.91 I have heard rumored that is being offered by GM due to the 1LE... And that the cost of parts may come in around 300 without install kit. That is substantially less than aftermarket, but if LPE makes OEM then quality wont be an issue.

Is the 3.91 too much for a street car when coupled with cam and blower? By the way I have narrowed it to Maggie or whipple if that matters....

audiomikej · 08-19-2012, 08:37 PM

3.91 is way too much for the A6, the A6 has a very tall 1st gear vs. M6. Go with 3.45 or 3.7x. 3.45 should cost the same as 3.91. If you are going big cam and big F/I go with 3.45 because you do not want to be shifting into 5th on the 1/4 track. 5th is a weak overdrive only gear. 1/8 track is okay for 3.7x

FloMoCamaro · 08-19-2012, 09:12 PM

3.70 gear + 720rwhp + Slicks = NO Traction. That being said, it really depends on type of FI you are going with and power level you end up with. But topically the more hp the higher the gear...

HufferSS · 08-19-2012, 09:18 PM

Pick up a diff from an M6 car...3.45...perfect.

FloMoCamaro · 08-19-2012, 09:43 PM

Quote:

Originally Posted by HufferSS

Pick up a diff from an M6 car...3.45...perfect.

brantley847 · 08-19-2012, 09:57 PM

My power level will probably top off around 560rwhp... With the future mods I'm mind I never expect 600.

Is there a seat of the pants difference with the 3.45 in a A6? I want to have a lil fun while I save up for the blower

grocerygetter · 08-19-2012, 10:02 PM

3.70s are fun...I have a feeling however that 3.45 may be faster at the track. If you can hook some 3.70s though. Bam. Our local track is 1k feet. Thus I went for fun street factor and figured I would try to hook some 3.70s.

LS7 427 · 08-19-2012, 10:12 PM

I have 737 rwhp + 3.70's + slicks and with proper coil over settings I have no problem hooking. Runs about a 1.5x - 60 foot. The problem is I trap at 5200 rpm in 5th gear at the track. Going to change to an LPE 9.5" rear end this winter with their 3.42 gears. As the fellows have said above the 3.45's from a manual trans is your answer.

Bryan

FloMoCamaro · 08-19-2012, 10:15 PM

3.27 to 3.45 has a real noticeable difference - I think you would be happy and save some money in the long run. Just my 2 cents...

camslambam · 08-19-2012, 11:04 PM

3.45

Pro Stock John · 08-19-2012, 11:07 PM

From a drag racing standpoint you'd look at shifting rpms, max rpm, tire size, rear gear and trans gearing.

LittleMT · 08-20-2012, 12:57 AM

Andy of ADM installed me the 3.45's on my 617rwhp whipple car.

I love it.

Fiftydriver · 08-20-2012, 08:50 AM

Conventional wisdom will tell you 3.73. If your building a strip car, 3.45s may be even better depending on how high you will go in power.

My car is a street only car. So most of my aggressive driving is on the roll so my 3.91 are exactly what I want and I could not be happier with them.

Just comes down to what you want to do with your car.

brantley847 · 08-20-2012, 09:50 AM

Quote:

Originally Posted by Fiftydriver

Conventional wisdom will tell you 3.73. If your building a strip car, 3.45s may be even better depending on how high you will go in power.

My car is a street only car. So most of my aggressive driving is on the roll so my 3.91 are exactly what I want and I could not be happier with them.

Just comes down to what you want to do with your car.

It will be a street car, I don't see myself picking up anything more than radials if I do decide to hit the strip. Unfortunately, I don't have much access to one so we are talking maybe once a year tops...

If it was a weekend or even monthly strip car I would have done 3.45s without asking. Do I launch from a stop on the street at 3 am? Sure... that is where this is becoming a hell of a decision.

08-19-2012, 08:17 PM	#1
brantley847 v It bites. Drives: 2011 IBM 2SS/RS Join Date: May 2008 Location: Orlando, FL Posts: 3,585	A6 gears for FI I am attempting to build a foundation for my auto to go FI in the next year or so... Obviously, many of you have experience with this so my question asthe subject suggests is what ratio is best for not only an A6 but to build me the foundation to eventually go FI. I was set on the 3.70-3.73 but it is hard to ignore the 3.91 I have heard rumored that is being offered by GM due to the 1LE... And that the cost of parts may come in around 300 without install kit. That is substantially less than aftermarket, but if LPE makes OEM then quality wont be an issue. Is the 3.91 too much for a street car when coupled with cam and blower? By the way I have narrowed it to Maggie or whipple if that matters....

08-19-2012, 09:12 PM	#3
FloMoCamaro Drives: 2010 Camaro SS Join Date: Dec 2009 Location: Flower Mound, TX Posts: 490 View My Garage	3.70 gear + 720rwhp + Slicks = NO Traction. That being said, it really depends on type of FI you are going with and power level you end up with. But topically the more hp the higher the gear... __________________

08-19-2012, 09:18 PM	#4
HufferSS I Wanna Go Faster!! Drives: 2011 2SS Synergy Green M6 Join Date: Apr 2011 Location: SC Posts: 3,323	Pick up a diff from an M6 car...3.45...perfect. __________________ Built by Vengeance Racing 9.31@154.81 mph Procharger F1-X RPM Level 7 4L80e + Coan Converter Hendrix 9" Rear Axle + 3.50 Gear ARH 2" LTs+3.5" Exhaust Fore Fuel System, Bogarts + Hoosier Slicks Pfadt Drag Pack Suspension My Build Thread \| Best Pass To Date

08-19-2012, 10:02 PM	#7
grocerygetter instigator Drives: 2020 6.2 Trail Boss, 2022 XC90 Join Date: Jan 2010 Location: 72034 Posts: 3,979 View My Garage	3.70s are fun...I have a feeling however that 3.45 may be faster at the track. If you can hook some 3.70s though. Bam. Our local track is 1k feet. Thus I went for fun street factor and figured I would try to hook some 3.70s. __________________ -John S.

08-19-2012, 10:12 PM	#8
LS7 427 10.11 @ 136.32 Drives: Black & Yellow 2SS/RS LPE LS7 427 Join Date: Mar 2010 Location: Redcliff, Alberta Posts: 957 View My Garage	I have 737 rwhp + 3.70's + slicks and with proper coil over settings I have no problem hooking. Runs about a 1.5x - 60 foot. The problem is I trap at 5200 rpm in 5th gear at the track. Going to change to an LPE 9.5" rear end this winter with their 3.42 gears. As the fellows have said above the 3.45's from a manual trans is your answer. Bryan __________________ My Build Journal Built, Tuned and Maintained By........

08-19-2012, 08:37 PM	#2
audiomikej Drives: the wife crazy talking Camaros Join Date: Aug 2010 Location: Lincoln, NE Posts: 277 View My Garage	3.91 is way too much for the A6, the A6 has a very tall 1st gear vs. M6. Go with 3.45 or 3.7x. 3.45 should cost the same as 3.91. If you are going big cam and big F/I go with 3.45 because you do not want to be shifting into 5th on the 1/4 track. 5th is a weak overdrive only gear. 1/8 track is okay for 3.7x

08-19-2012, 09:57 PM	#6
brantley847 v It bites. Drives: 2011 IBM 2SS/RS Join Date: May 2008 Location: Orlando, FL Posts: 3,585	My power level will probably top off around 560rwhp... With the future mods I'm mind I never expect 600. Is there a seat of the pants difference with the 3.45 in a A6? I want to have a lil fun while I save up for the blower

08-19-2012, 10:15 PM	#9
FloMoCamaro Drives: 2010 Camaro SS Join Date: Dec 2009 Location: Flower Mound, TX Posts: 490 View My Garage	3.27 to 3.45 has a real noticeable difference - I think you would be happy and save some money in the long run. Just my 2 cents... __________________

08-19-2012, 11:04 PM	#10
camslambam Account Suspended Drives: 2010 SS, 06 SRT10 Ram Join Date: Nov 2011 Location: C. America Posts: 1,658	3.45

08-19-2012, 11:07 PM	#11
Pro Stock John Writer Drives: 2010 SS / 1967 Camaro Join Date: May 2009 Location: Chicago, IL Posts: 7,216	From a drag racing standpoint you'd look at shifting rpms, max rpm, tire size, rear gear and trans gearing. __________________ PROJECT HEAVY CHEVY Camaro Now: Mods for the Masses Part I \| Part II 13.15@106 1.95 \| 100% Stock 12.37@112 1.85 \| + Kooks Headers/Cats + 20" 555R + CAI + BW TB + UDP + Tune 12.06@113 1.70 \| + CD 3200 + 18" NT05R + RCR Intake + NE OTR + GPI Tune 11.84@115 1.59 \| + 3.91s + Race Star 17x7 Fronts 10.90@125 1.47 \| + GPI VVT Cam + BW Ported Heads + CD 3800

08-20-2012, 12:57 AM	#12
LittleMT user bann'd Drives: Chevy SS Join Date: May 2009 Location: Hepcat City Posts: 1,463	Andy of ADM installed me the 3.45's on my 617rwhp whipple car. I love it. __________________ Chantilly Lace, the 2011 Rockabilly Jukebox..ADM built..617rwhp, geared A6.

08-20-2012, 08:50 AM	#13
Fiftydriver Drives: 2010 Camaro 2SSRS RJT L99 Join Date: Jun 2010 Location: Fort Shaw, Montana Posts: 1,242	Conventional wisdom will tell you 3.73. If your building a strip car, 3.45s may be even better depending on how high you will go in power. My car is a street only car. So most of my aggressive driving is on the roll so my 3.91 are exactly what I want and I could not be happier with them. Just comes down to what you want to do with your car. __________________ Fiftydriver 2010 SSRS, RJTC, L99, Maggie 2300 SC, 3.4" pulley, Roto-Fab CAI, Dynatech Supermaxx LT headers, Dynatech High Flow cats, Corsa Cat back exhaust, Dual Elite Engineering catch can, MSD wires and Jannetty custom tune, JRE custom diff w/ posi mod, 3.91 LPE gears, Pfaht trailing arms, Pfaht trailing arm and Diff bushings, drop springs and sport sway bars front and back, Fesler dual guage pillar pod w/ AM Cobalt Boost and A/F guages. More to come!!