[JIMBO]

This coould be a controversial thread ->) ! But it's a honest assessment question at the least !
I've been talking to a buddy about this topic how a 373 vs 410 gear would compare on a street roll.
We're deciding what is the advantage of a gear trade off.

Lets say you have 2 same model GT500's ....or Mustangs and one makes 20RWHP more.
So say one makes 650FWHP with 410's ....the other 670 with 373 gears.

They are rolling along at 25mph. One has 373's ( likely in 1st maybe 3000rpm?).
The other has 410's ( likely in 2nd maybe 2500rpm?)
Assume they both get traction with MT's or Nittos. They hit it together and go thru to top of 4th gear.
Does the 410 geared car get out and stay out a bit all way to top of 4th ?
Or does the 373 geared car gather up the top end and make it's moves tp pass the winding 410 at the top of each shift ?

We agreed of course at the top of 4th the 373 would have 1-2-300rpm of mph left. We could equalize that by running it to 125mph. We were thinking about effect of 410's even if it's just a 2nd to 3rd wind out.
I'm thinking with all else being equal ( traction) the 410's get the jump using torque and quick revving and stays out
despite giving up the extra 20 HP .

 

[tmoss]

I suspect the driver will make more difference

 

[JIMBO]

Yeah...no doubt driver is a factor. As I think about it...I'm still leaning towards the 410's eating up pavement to move out front of 373's. Gears matter ..especially with these heavy cars.

 

[quikbluewagon]

I've run both 4.10s and 3.73s without changing anything else with the car. While the 4.10s were great from a dig, the 3.73s had way longer legs. My 4.10 car would run out of steam way too quickly especially running to the top of 4th. I went back to a 28 inch tire with the 4.10s just so I could keep up with the cars I had previously bested with 3.73s.

 

[JIMBO]

I have the 4.10's in my '13 and also have a taller 305x20 MT so I imagine the gears actually come out to 3.90's given there's 1.75" more tire height. Maybe that's why I felt such a kick in the pants going from 373 to 410 because the 373's were likely in the 360's range.
What I believe I felt with the 410's was very quick boost build & more power after the shifts.

When we were talking about 4.10 vs 3.73's on a 2nd-4th street roll....the race would very likely be over by top of 4th.
With my own car on an empty rural highway that's 130-135mph . I've only stayed in it that long vs my friend's ZR1.
Otherwise...I'm very likely lifting way before that.
For the track ? I'd probably learn something there and be back to my 3.73's.

I imagine your mph was better with the 373's.
But when you mentioned " keeping up with cars you previously bested" did you feel the 373's pulled harder on the street at top rpms or mostly rather than run out of rpm pulled harder passing the trap ?

 

[quikbluewagon]

Yes, my car pulled harder with the 3.73s. I have some videos on my GoPro of races with a group of cars on 2 separate nights. The night we ran and I was using the 3.73s, I could easily walk these other cars on a 2nd through 4th run. After going to 4.10s, I would just watch them walk away. The 4.10s were great at the track for e.t.s but I never got out of 3rd gear and my 1/8th mile was [email protected] With the 3.73, I typically ran [email protected]

On the highway, I could pull to around 130 in 4th with the 4.10s and 145 with the 3.73s. I ran a T56 and 26" tire. I ended up going to a 28" tire to get some of that top end back. With my new build, I am back to a 3.27 rear gear, a built automatic, and added 350hp so I am really curious to see how the car will respond now.

 

[JIMBO]

Gee..I wonder if you could have been slipping a bit with the 410's on the street given your 8th mile differences ?
Either way it sure sounds like you're putting together a real kick-butt combo now Bud !

 

[JIMBO]

I was out in my buddy's 07 GT500 yesterday. He made 695rwhp on a dynojet with 410's but then switched to 373's . Given his wheels are identical to mine , taller 20" 305 MT's his rear gear comes in around 3.63. His mods are '13-14 Trinity, stock 2.67 upper pulley, 10% lower pulley, stock elbow , CJ 65 TB, JLT 123CAI, headers, hogged out Cats, MCleod RXT, Magnaflow axle backs. He's running the #56 injectors but given the 07 fuel pumps I wish he had Boost-A-Pumps ! But his tuner said not needed. I used my Visa for his Trinity swap for him to avoid the wifey thing which was not an issue. Geeze...he makes great HP for that combo !

My '13 makes 680rwhp on 410's, same dyno, same wheels so my actual rear gear is more like 3.90's, Trinity with 2.4 upper pulley , BPS O-sized plenum, VMP 67 TB, JLT123CAI, stock lower pulley, headers, Mcleod RXT, Corsa Sport axle backs. Only difference might also be I have an ALFW and the '13 has the CF drive shaft...but seat of the pants cannot measure that.

I'd have no idea how we'd do vs one another because Holy Moly his car is FAST ! My 410's seem a bit quicker on the hit but the thing is I'd approach ANY roll race from a different RPM with my 410's than when I had 373's. In his car 2nd gear needed at least 2800-3000rpm for a quick burst whereas mine would prefer anywhere from 2000-2400 rom with 410's. Same in 3rd gear. At 3500rpm on a roll my car "explodes" in 3rd gear. His car needs closer to 4000rpm and the power build up is a bit different. I thought I'd be able to tell the difference but not as a passenger getting tossed around and even as a driver I hit it 3 times ...2nd/3rd/4th but.....there's so much going on ->) !
I imagine he's got a better shot out of the hole.....then again....he was rippin them loose no matter where he stabbed 1st gear .

My '13 has the longer 1st gear but no way would I ever stab the pedal in 1st..anywhere on the street. IF I went from the dead I'd turn my TC ON ( it's always off) and pedal it out 2/3 throttle pulling 2nd gear ( no lift) around 5500 before I drop the pedal. Someday this season I'm sure we'll go out and play. That's should be a blast ! I think it would be my advantage to start down low...perhaps 20-25mph as I'd be in 2nd gear in a proven scenario for dead hook. No doubt he'd be in 1st which would likely present a challenge. Both of us power shift and are pretty quick on the stick so that's not to either advantage. Our best exchanges would be from a higher 3rd gear roll....so perhaps it would turn out to be the battle for the " sweet spots! ".

I'm not concerned about top end because I wind out in the 135+ range near 6800rpm......AIN'T NO WAY we're going much faster than that even on a wide open rural road ->) ! Still Luvin my 410's. But ya never know ! I may have answered my own post....that being there are just too many variables.
But Ya Never know...Not likely cause I've had them before ....but....One race could change my mind back to 373's ->) !

 

[TBBC]

Interesting thread, that would be really hard to say, as mentioned driver makes the biggest difference

 

[JIMBO]

Months have passed but the new season and spring mods are soon upon us. I spoke with my local Mustang shop. I was more concerned about rolls since even 373's are a tough one with my TQ. I use TC On if/when that rare event arises.. The shop advised if I can hook 410's anywhere from 15-30mph that should result in a quicker hit and move ahead. Unless goal is top end mph at the very top end he felt the difference would be minimal. Power shifting & driver control help! Power shifting 2-3-4 was never an issue. Street surface is major and I'd not go hard on smooth new asphalt type surfaces anywhere. Staying with the 410's (390 on taller wheels).
Thanks for the advice fellas.
jam

 

[TomR]

If the vehicle can use the additional off the line hit from a high numerical ratio rear, then you want to gear for maximum ratio unless you run out of top end.

If you are tire traction limited when punching it from a roll in low, more gear ratio is a waste of time.

Every car I have ever had since 1966 behaves this way. My 2014 auto GT, 2011, and 2013 behaved this way. My 1989 turbo behaves like this, as does my 1992 chassis car. My 1969 Rambler SC 4 speed and 1983 chassis car with lenco 5 speed were the same, as was my 1966 GT K code and a 409 4 speed Biscayne I had.

If you can just nail it while rolling and spin when on the best surface, any additional gearing will be a waste. It won't do a thing except slow you down.

 

[JIMBO]

Thanks Tom...I have a 5 speed and despite the 2.97 1st gear ratio even 373's are quite a challenge from the dead on the street.
The 410's are a little less manageable but it still comes out feathering with TC on pretty darn good. And I can get to 2nd with minimal tire slip. Am I launching? Heck no. Can't do that with 600ftlbs TQ at 2800rpm on 20" street DR's at 21psi.
With 373's if I hit it on slow roll in 2nd at 15mph there's a slight lag but it's only monetary then it's off! From 25-30 it comes on the moment it's stabbed. With the 410's it's around 2200rpm at 15-20mph and it hits hard, lifts and hooks which makes these gears lotsa fun on the street. If it's a good pavement 25-30 mph it's right there in the tq band it's game on. An important thing about this type of street stuff is the stab. I've had guys drive my car and all they say is it slips everywhere...overpowered. My response is stab it like a mad hornet...dent the floor! But unless it's your car it's difficult to get "that feel". An MT DR on the street is best when it's shocked.
Ready for new tires later this season and I'm being told the Nitto NT05R hooks better than the MT on the street. Like all the cars you mentioned which seem like kick-ass cars....you need to get to the point where everything works together and stay with that combo. The 410's are working for me especially with new LCA's set at an aggressive angle. The Nitto swap would be a big investment I'm pondering for a bit. It's not easy to part with what you know! MY '13 GT500 is 2tons of fun....but at 3900lbs it's a heavy ass car!
Sometimes a little more gear gets the big tug boats going! Haven't been to the track yet but calculations figure with my tall tire it will be around 6800rpm thru the traps. The redline not to be visited too often ->) is 7K.

 

[BadAndy]

I initially had 3.73s installed in my '08 GT500 and loved them but jesus fuk they were LOUD. Tried another set and same problem. Ended up dropping to 3.55s with slightly less noise but still far better than the 3.31s.

 

[midnightlaundry]

They are both useless in 1st gear on the street..

 

[BadAndy]

They are both useless in 1st gear on the street..

LOL yep!! Even with better tires, 1st gear is a pain.