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Discussion Starter #1
The synchros for second and third gear in my 95 GSR are shot. I can't slam second for racing and third gear shift at high rpms causes a nasty crunching sound. I was told it wasn't worth it to rebuild the transmission, to just put a used one in (by mechanics). I'm thinking about rebuilding myself though. I found LS tranny internals at sofast.com. I have the mechanical knowledge to do this project on my own, I have two questions though.
1. Is it true that the LS gear ratios are better for the GSR in the 1/4 mile and can a little light be shed on gear ratios and how the effect the cars performance.
2. Has anyone tried such a project themselves or have any suggestions/comments.
 

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Discussion Starter #3
Wow, was he taking his time or what??? Doesn't happen to be a TI member does he?
 

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Nah, it was some dude working on his bronco, but he had no idea what he was doing and just followed directions. Thats the only instance Iv'e heard of someone doing it though. However if you look on ebay you can find a tranny with like 50k going for pretty cheap.
 

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The LS gear ratios are longer, so it would slow you down in the 1/4 mile. Unless you are running alot of boost, I would look for GSR, or maybe even ITR/B16 gear ratios/tranny.

I am sure it's possible to do, just alot of work :)
 

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the only advantage to having a taller gear is if you have a lot of wheelspin or you have to shift before the 60 ft mark...both of these will slow your 1/4 mile time.

Some believe that launch speed is important since the hole shot or initial speed determines or affects your final trap speed. Start with a higher speed and with all else being equal, you'll finish at a higher speed. This is the "conventional" thinking.

However, a higher final trap speed does NOT mean you will have a lower 1/4 mile time than the other guy. This bends a lot people's noodles. They don't understand it. They think a higher speed must mean you ARE going faster than the other guy. Think again.

Remember this is not the Bonneville salt flats. We are NOT shooting for top speed. We ARE shooting for the highest acceleration.

This is where people misunderstand 1/4 mile runs and gearing. We are going for the lowest time and not the highest speed. Acceleration, by definition (look it up in your dictionary) is how fast your speed climbs. That means how fast that speedometer needle climbs up the dial. So if you get to 100 mph speed faster than the other guy, you will have a lower 1/4 mile time, even though he may end up with a higher final trap speed.

Shorter gearing (where the first number of the ratio is larger or higher like in an ITR) accelerates faster but has a lower top speed. The LS with taller gearing (the first number of the ratio is lower) will have a higher top speed but accelerate less. The advantage of taller gearing of the LS comes in the first 2 gears where it causes less traction and wheelhop problems and eliminates you from spending time shifting at a critical point, the 60 ft mark, especially in big hp cars.

So ideally we would want a tall 1st and maybe 2nd (although not as important) and then have a short 3rd and 4th gear for acceleration.

The last thing you should consider is the relationship of the gears to the powerband of your engine. If your gearing is not spaced correctly between the gears, it may result in your revs dropping below the rpm at which your powerband exists. The gear ratio and the spacing between gears determine if you stay in the powerband...which is the name of the going faster game. You should know from a dyno plot where your highest torque is and how long you stay there...that's your powerband location.

And as we know, powerband location can be controlled by the parts you choose for your engine build up.

So to answer your question, in a N/A car making less than 180 whp, and having a high powerband location, the taller gear ratios will not help accelerate you faster. The LS 1st gear ratio in fact is identical to the GSR and ITR 1 st gear ratio but the LS final drive drops it to a lower level. So you may gain some traction advantage through first from the taller final drive in first but the gears after that drop you into a lower rpm and may drop you out of your powerband. Secondly, the revs climb more slowly through each gear when the gear ratio is taller. So it takes longer to build up your speed. Remember, we want to accelerate faster, meaning we want the speed to build up faster...the faster your speed increases, the lower your et. We aren't at Bonneville where they go farther than a 1/4 mile.
 

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oh yeah, last point...the beauty of owning a 2nd and 3rd gen integra is the fact that the Bseries trannies' gear ratios and final drives can be mixed and matched . So you can swap out ratios and long as you use the right spacer, clearances, and countershaft.

The gearing is dictated by the multiplication (or mathematical product) of the gear ratio and the final drive.

shorter final drives can save you from swapping out gears and can convert a tall gear set into a shorter, faster accelerating gear set.

You all have already seen my acceleration comparison of a stock GSR with GSR tranny but with a JDM ITR final drive as compared to the acceleration graph of a stock ITR. Despite being 25 crank hp down on power to the ITR, the GSR with that final drive accelerates as well as the ITR through to 4th gear.
 

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Discussion Starter #8
Thanks a lot Michael. I've been through the trap speed debate with friends and have trouble making them see how lower e.t. is achieved with a lower trap speed, oh well. And I'm glad to get a definative answer on the LS ratios in a GSR, what I'd been hearing never made sense. I supposed every one I heard that from is in the dreamland of sub 10 second 1/4 miles and gobs of boost. So far I've only been able to find the LS tranny internals. Anyone have links or leads on GSR and ITR (JDM maybe) transmission internals? I'm going to look into the JDM final drive. Thanks Again.
 

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My friend has a 2000 Civic SI with ITR limited slip differential, and he has an LS 5th gear. He upgraded his synchros, and coulnd't you just get new, better synchros instead of rebuilding the whole transmission?
 

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i'm using the y1 cable tranny. it has a 1st gear of 3.166, vs. the ls 1st gear of 3.230 i believe. its really good outta the hole, but the .870 5th gear kinda sucks. good thing the FD is 4.266.

i want to swap out gears and use the
y1 1st gear, 3.166
j1 2nd gear, 2.105
j1 3rd gear, 1.458
j1 4th gear, 1.107
LS 5th gear, 0.742
FD4.400

i'm wondering if i'll wreck my 0-60 ft time by going with the 4.400 FD and the 3.166 1st gear. and i'm also wondering if i should use the y1 2nd gear instead (2.052)
 
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