HP vs Gear Ratios: Real World Performance + ROI

Paul4223

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There is but one major change I could make on my car at this point, and I'm not talking about a hotter engine. Mine's a pretty warm 302 hooked up to a close-ratio box, and I'm not remotely inclined to go "wilder" in the engine compartment. The motor is too good and is barely broken in.

That got me thinking again, about the relationship between HP and gearing for "real world" seat-of-the-pants performance in our cars. I'm talking about freeway on ramp exercises, pedal-to-metal when you're certain the "coast is clear" and possibly an occasional visit to a drag strip. I'm not a good enough driver to put my car on a track.

It seems to me, that once you've got a decent engine, that the biggest return on investment would be lower gears, most logically in the transmission.

There's no way I would convert to a 5-speed at this point but a wide-ratio toploader seems to be the simplest, most direct, and most rational performance improvement.

I realize this is a topic often discussed, so please forgive me if this post puts you to sleep. I'm basically thinking out loud, to a community of hard-core Tiger enthusiasts. :)
 
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michael-king

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There is but one major change I could make on my car at this point, and I'm not talking about a hotter engine. Mine's a pretty warm 302 hooked up to a close-ratio box, and I'm not remotely inclined to go "wilder" in the engine compartment. The motor is too good and is barely broken in.

That got me thinking again, about the relationship between HP and gearing for "real world" seat-of-the-pants performance in our cars. I'm talking about freeway on ramp exercises, pedal-to-metal when you're certain the "coast is clear" and possibly an occasional visit to a drag strip. I'm not a good enough driver to put my car on a track.

It seems to me, that once you've got a decent engine, that the biggest return on investment would be lower gears, most logically in the transmission.

There's no way I would convert to a 5-speed at this point but a wide-ratio toploader seems to be the simplest, most direct, and most rational performance improvement.

I realize this is a topic often discussed, so please forgive me if this post puts you to sleep. I'm basically thinking out loud, to a community of hard-core Tiger enthusiasts. :)

Wide ratio gears is the best option after a 5 speed... I have alower rear end.. and really its the worst of both worlds
 

TigerBlue

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827
3.31:1

I love the way our Tigers respond with a close ratio toploader through the gears with the 3.31 gear. Grrreat off the line or from a green light and will run well over 100 mph. (do not try this on public roads) Positraction or a Torsen type geared limited slip help to get going with more acceleration and less smoke.

HP? Blue over 300 (302) and Black 200 + (260) Gas mileage suffers some it is true but the 2.88 is awful with first gear of a close ratio trans.

A wide ratio trans helps first gear but you lose the some of the fun and efficiency of the tight spaced close ratio which keeps engine operation in the power band.

If your priority is gas milage? get a five speed. If your priority is driving? I do not think you can beat a 3.31 and close ratio box.

Rick
 

michael-king

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Hey Rick,

Seesm we have different experience.. i guess this also should assist in th einformation.. what do we want to use the cars for.. and "what" rear end ratio.

For me i have the C/R box and the 3.07 set .. 1st is still quite tall and i dont get the accerlation I would get with a shirt ratio 1st gear. I also dont get relaxed cruising onthe freeway of the 2.88 or an O/D 5th.... I should also note i have 175/60/14's on the car which also lowers the effective overall gearing.

I guess i would liek the 5 speed for the brutal off the line stuff and the relaxed cruise...

I buy intot he C/R box being great on a race track.. it really is.. but the stock tiger doesnt really get the oportunity to use the stacking around the street as 1st is so tall.. and i feel the lower rear end hurts what you use most.. crusing to an event....

Each to their own... i would say that if i had a 5 speed.. i'd probably drop in a 3.31 or 3.54 ... :D ...
 

hottigr

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816
depends on...

A lot of factors. I'm running 2.88's with the close ratio tranny, but, I also have 60 series tires on 13" rims. With this set up, the gearing is just fine.
 

Paul4223

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Messages
159
Wide ratio gears is the best option after a 5 speed... I have alower rear end.. and really its the worst of both worlds

Hi Michael:

So you have a close-ratio box and lower RE. How low, may I ask?

I once drove a buddy's Tiger quite a long distance including Calif city streets and freeway. 302, close-ratio, and 3.07 RE. It did not feel noticeably better off the line, and at freeway speeds I subconsciously keep reaching for "fifth." Seemed like a waste.

I'm not math wizard, but remember seeing some figures equating first gear in a WR box with about at least 3.30-something or maybe even lower, RE.

Short of going to a 5 speed, that sounded pretty sweet to me.

I should have added that on my car, I'm running 15" Panasports- I'll check tire sizes.
 

XTIGERX

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Messages
501
I'm talking about freeway on ramp exercises, pedal-to-metal when you're certain the "coast is clear"

I enjoy those every chance I get. There used to be a nice little "S" on-ramp with a straight ramp at the top to merge with traffic near the house. I flew up that ramp once while checking my Wink for traffic I was merging with and spotted an LA City police car and sure enough I heard on his loudspeaker "slow that thing down". I wasn't going real crazy fast but faster than he was but he didn't even bother me other than that verbal.
 

0neoffive

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More Fun Than Smarts, BUT . . . .

I enjoy those every chance I get. There used to be a nice little "S" on-ramp with a straight ramp at the top to merge with traffic near the house. I flew up that ramp once while checking my Wink for traffic I was merging with and spotted an LA City police car and sure enough I heard on his loudspeaker "slow that thing down". I wasn't going real crazy fast but faster than he was but he didn't even bother me other than that verbal.

There's a stretch of I-89 over the VT border where you crest a rise and discover 6- 7 miles of gentle curves & straightaways laying out before you. It's almost impossible for guys with gear-head temperament not to test the limits a tad. At the coffee shop/truck stop some miles later the door opened and the two smiling badge wearers queried , " Okay, who owns the little green airplane?" true story
 

michael-king

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Hi Michael:

So you have a close-ratio box and lower RE. How low, may I ask?

I once drove a buddy's Tiger quite a long distance including Calif city streets and freeway. 302, close-ratio, and 3.07 RE. It did not feel noticeably better off the line, and at freeway speeds I subconsciously keep reaching for "fifth." Seemed like a waste.

I'm not math wizard, but remember seeing some figures equating first gear in a WR box with about at least 3.30-something or maybe even lower, RE.

Short of going to a 5 speed, that sounded pretty sweet to me.

I should have added that on my car, I'm running 15" Panasports- I'll check tire sizes.

as in aboive post .. ;-) ..

I have the C/R box and the 3.07 set .. 1st is still quite tall and i dont get the accerlation I would get with a shirt ratio 1st gear. I also dont get relaxed cruising onthe freeway of the 2.88 or an O/D 5th.... I should also note i have 175/60/14's on the car which also lowers the effective overall gearing.

my motor is a 302 340hp roller setup
 

Paul4223

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Messages
159
as in aboive post .. ;-) ..

I have the C/R box and the 3.07 set .. 1st is still quite tall and i dont get the accerlation I would get with a shirt ratio 1st gear. I also dont get relaxed cruising onthe freeway of the 2.88 or an O/D 5th.... I should also note i have 175/60/14's on the car which also lowers the effective overall gearing.

my motor is a 302 340hp roller setup

Your car is, essentially, a motor and drivetrain mirror of my buddy's. NOW I completely understand why it's "the worst of all worlds". :) Thanks.

Dedicated WRF (wide ratio fund) starting NOW!

I checked the specs on my rear tires: 225-50-R15. 23.9" diameter. Doesn't exactly help the car "leap of the line" does it? :)
 
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wag123

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Messages
130
I have the close-ratio gears and a 2.88 rear end. I really dislike this combination for normal street driving because it requires far too much effort and concentration to get the car moving from a dead stop.
I have a buddy that has the close-ratio gears and a 3.31 rear end. His car drives great at low speeds, but the engine literally SCREAMS on the highway. He has decided to go back to the 2.88 rear end and upgrade to the wide-ratio gears.
I have another buddy that has the wide-ratio gears and a 2.88 rear end. I have driven his car and I have to tell you that it is a pleasure to drive compared to mine! Because of the engine's torque and the Tiger's light weight, I didn't find the larger RPM drop between the gears to be any problem at all. So, short of spending the BIG bucs on a 5-speed conversion, IMHO this is the combination to have in a Tiger.
 

Paul4223

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Messages
159
I have the close-ratio gears and a 2.88 rear end. I really dislike this combination for normal street driving because it requires far too much effort and concentration to get the car moving from a dead stop.
I have a buddy that has the close-ratio gears and a 3.31 rear end. His car drives great at low speeds, but the engine literally SCREAMS on the highway. He has decided to go back to the 2.88 rear end and upgrade to the wide-ratio gears.
I have another buddy that has the wide-ratio gears and a 2.88 rear end. I have driven his car and I have to tell you that it is a pleasure to drive compared to mine! Because of the engine's torque and the Tiger's light weight, I didn't find the larger RPM drop between the gears to be any problem at all. So, short of spending the BIG bucs on a 5-speed conversion, IMHO this is the combination to have in a Tiger.

Thanks for your post. Now that I have a much better understanding of the "gearing issues" on our cars, the solution in my situation is to retain the 2.88's and go with a wide-ratio Toploader.

It offers the largest ROI by far. It's the most affordable solution for me, and the results should prove to make the car much more enjoyable to drive.

Thanks to all who contributed to this thread. Once I find a hard top, and install the wide-ratio, my car will finally be finished, after all these years. :D
 

dude234

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Messages
182
I have another buddy that has the wide-ratio gears and a 2.88 rear end. I have driven his car and I have to tell you that it is a pleasure to drive compared to mine! Because of the engine's torque and the Tiger's light weight, I didn't find the larger RPM drop between the gears to be any problem at all. So, short of spending the BIG bucs on a 5-speed conversion, IMHO this is the combination to have in a Tiger.

What size tires does your friend have on his Tiger?
 

hottigr

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more than one way to change your gearing...

According to the shop manual, the diameter of the stock tires (5.90-13) is 24.1". The 205/60-13 tires I'm currently running have a diameter of 22.7". That makes my stock rear end (2.88) the equivalent of having 3.06 gears (rounded off). Like I said, just about perfect. I really don't have any trouble getting off the line- unless it's uphill- then I just use the hand brake! I still prefer the close ratio gear set for driving...
 

steven

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Messages
875
Thanks for the replies, I have the original unmolested close ratio still bolted to the 260. Also have a close ratio from a 64 Mustang. Bought a rebuild kit and will be swapping gears once my 289 is reassembled. After all this, will have to see if my bid on a LSD diff was successful. :D
 

Paul4223

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Messages
159
Another Way to Change Gearing:Question

According to the shop manual, the diameter of the stock tires (5.90-13) is 24.1". The 205/60-13 tires I'm currently running have a diameter of 22.7". That makes my stock rear end (2.88) the equivalent of having 3.06 gears (rounded off). Like I said, just about perfect. I really don't have any trouble getting off the line- unless it's uphill- then I just use the hand brake! I still prefer the close ratio gear set for driving...

Interesting you mention this- I was wondering about this very thing. It certainly would be an easier method rather than dealing with the gearbox and/or differential.

I did a quick Google search for a calculator but no luck. I'll try again when I have more time. Do you by chance have such a calculator? I never was good at math. :)

I called Tire Rack but the guy I spoke to did not have a clue WTF I was talking about. My rear tires are 225-50-15 23.9" diameter. RE is standard 2.88.

Thanks for any guidance.
Paul
 

66TigerMK1A

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Messages
1,129
Interesting you mention this- I was wondering about this very thing. It certainly would be an easier method rather than dealing with the gearbox and/or differential.

I did a quick Google search for a calculator but no luck. I'll try again when I have more time. Do you by chance have such a calculator? I never was good at math. :)

I called Tire Rack but the guy I spoke to did not have a clue WTF I was talking about. My rear tires are 225-50-15 23.9" diameter. RE is standard 2.88.

Thanks for any guidance.
Paul

Here's a chart of tire sizes that are more or less pertinent to Tigers... They may not all be available and may vary slightly between manufacturers but give you some idea anyway...
Paul.. I sent you a calc. by email... :cool:


Jim
B382000446
 
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